Spatio-Temporal Changes of Net Primary Productivity and its Response to Phenology in Northeast China during 2000-2015

NASA Astrophysics Data System (ADS)

Qiu, Y.; Zhang, L.; Fan, D.

2018-04-01

The relationship between net primary productivity (NPP) and phenological changes is of great significance to the study of regional ecosystem processes. In this study, firstly, NPP was estimated with the remote sensing model based on the SPOT-VGT NDVI dataset (2000-2015), meteorological data and the vegetation map in Northeast China. Then, using NDVI time series data which was reconstructed by polynomial fitting, phenology was extracted with the dynamic threshold method. Finally, the relationship between NPP and phenology was analyzed. The results showed that NPP mainly increased in the cropland, grassland, forestland and shrubland; however, vegetation NPP decreased in the ecotone among cropland, grassland and forestland. Correlation analysis suggested that the relationships between NPP and phenological metrics (i.e., the start of the growing season (SOS), the end of the growing season (EOS), the length of the growing season (LOS)) were different due to geographical location. On the whole, there was a positive correlation between NPP and the LOS in the forestland, and negative in the cropland and grassland, indicating that extended LOS can promote the accumulation of forestland NPP. By analyzing the monthly NDVI data during the vigorous growth period, the increase of NPP in the grassland and cropland was mainly due to the better growth from June to August, and shortened LOS did not lead to reduce the NPP. Generally, the response of NPP to phenology in Northeast China were more complex, showing obvious difference of vegetation types and spatial variability, we need to consider topography, community structure and other factors in the further studies.

Optical and Acoustic Device Applications of Ferroelastic Crystals

NASA Astrophysics Data System (ADS)

Meeks, Steven Wayne

This dissertation presents the discovery of a means of creating uniformly periodic domain gratings in a ferroelastic crystal of neodymium pentaphosphate (NPP). The uniform and non-uniform domain structures which can be created in NPP have the potential applications as tunable active gratings for lasers, tunable diffraction gratings, tunable Bragg reflection gratings, tunable acoustic filters, optical modulators, and optical domain wall memories. The interaction of optical and acoustic waves with ferroelastic domain walls in NPP is presented in detail. Acoustic amplitude reflection coefficients from a single domain wall in NPP are much larger than other ferroelastic-ferroelectrics such as gadolinium molybdate (GMO). Domain walls of NPP are used to make two demonstration acoustic devices: a tunable comb filter and a tunable delay line. The tuning process is accomplished by moving the position of the reflecting surface (the domain wall). A theory of the reflection of optical waves from NPP domain walls is discussed. The optical reflection is due to a change in the polarization of the wave, and not a change in the index, as the wave crosses the domain wall. Theoretical optical power reflection coefficients show good agreement with the experimentally measured values. The largest optical reflection coefficient of a single domain wall is at a critical angle and is 2.2% per domain wall. Techniques of injecting periodic and aperiodic domain walls into NPP are presented. The nucleation process of the uniformly periodic domain gratings in NPP is described in terms of a newly-discovered domain structure, namely the ferroelastic bubble. A ferroelastic bubble is the elastic analogue to the well-known magnetic bubble. The period of the uniformly periodic domain grating is tunable from 100 to 0.5 microns and the grating period may be tuned relatively rapidly. The Bragg efficiency of these tunable gratings is 77% for an uncoated crystal. Several demonstration devices which use these periodic structures are discussed. These devices are a tunable active grating laser (TAG laser), a tunable active grating (TAG), and a tunable acoustic bulk wave filter.

Infrared, Raman and density functional characterization and structural study of 2-Nitro-2-phenyl-propane-1,3-diol

NASA Astrophysics Data System (ADS)

Kaya, Mehmet Fatih; Bağlayan, Özge; Kaya, Esma Güneş; Alver, Özgür

2017-12-01

Nitro compound and nitro derivatives are industrially important to produce rubber and agricultural chemicals. In this study, one of the promising derivatives of nitro compound 2-Nitro-2-phenyl-propane-1,3-diol (2NPP) is examined in detail. FT-Infrared and dispersive Raman spectra of 2NPP (C9H11NO4) were respectively recorded in 4000-10 cm-1 and 4000-100 cm-1. The bond distances and angles, conformational distributions, vibrational frequencies and the assignment of each mode, some thermodynamic parameters and reactivity descriptors: total energy, hardness, chemical potential, electrophilicity index, electronegativity, frontier orbitals energy gap of 2NPP were investigated by using DFT/B3LYP method with 6-31++G (d,p) basis set. In order to locate the global minimum on the potential energy surface of 2NPP, a beforehand conformational examinations were carried out using Spartan 10 along with semi-emprical PM6 method. The results of conformational analyses showed that there are five possible conformations having energies under 2 kcal/mol. Comparison of the theoretical and experimental results clearly indicates that density functional hybrid B3LYP/6-31++G (d,p) level of theory can be used to predict vibrational frequencies and structural parameters of 2NPP. Further, C1 geometry is considered to be the global minimum conformation of 2NPP.

Effects of vegetation heterogeneity and surface topography on spatial scaling of net primary productivity

NASA Astrophysics Data System (ADS)

Chen, J. M.; Chen, X.; Ju, W.

2013-03-01

Due to the heterogeneous nature of the land surface, spatial scaling is an inevitable issue in the development of land models coupled with low-resolution Earth system models (ESMs) for predicting land-atmosphere interactions and carbon-climate feedbacks. In this study, a simple spatial scaling algorithm is developed to correct errors in net primary productivity (NPP) estimates made at a coarse spatial resolution based on sub-pixel information of vegetation heterogeneity and surface topography. An eco-hydrological model BEPS-TerrainLab, which considers both vegetation and topographical effects on the vertical and lateral water flows and the carbon cycle, is used to simulate NPP at 30 m and 1 km resolutions for a 5700 km2 watershed with an elevation range from 518 m to 3767 m in the Qinling Mountain, Shaanxi Province, China. Assuming that the NPP simulated at 30 m resolution represents the reality and that at 1 km resolution is subject to errors due to sub-pixel heterogeneity, a spatial scaling index (SSI) is developed to correct the coarse resolution NPP values pixel by pixel. The agreement between the NPP values at these two resolutions is improved considerably from R2 = 0.782 to R2 = 0.884 after the correction. The mean bias error (MBE) in NPP modeled at the 1 km resolution is reduced from 14.8 g C m-2 yr-1 to 4.8 g C m-2 yr-1 in comparison with NPP modeled at 30 m resolution, where the mean NPP is 668 g C m-2 yr-1. The range of spatial variations of NPP at 30 m resolution is larger than that at 1 km resolution. Land cover fraction is the most important vegetation factor to be considered in NPP spatial scaling, and slope is the most important topographical factor for NPP spatial scaling especially in mountainous areas, because of its influence on the lateral water redistribution, affecting water table, soil moisture and plant growth. Other factors including leaf area index (LAI), elevation and aspect have small and additive effects on improving the spatial scaling between these two resolutions.

Effects of vegetation heterogeneity and surface topography on spatial scaling of net primary productivity

NASA Astrophysics Data System (ADS)

Chen, J. M.; Chen, X.; Ju, W.

2013-07-01

Due to the heterogeneous nature of the land surface, spatial scaling is an inevitable issue in the development of land models coupled with low-resolution Earth system models (ESMs) for predicting land-atmosphere interactions and carbon-climate feedbacks. In this study, a simple spatial scaling algorithm is developed to correct errors in net primary productivity (NPP) estimates made at a coarse spatial resolution based on sub-pixel information of vegetation heterogeneity and surface topography. An eco-hydrological model BEPS-TerrainLab, which considers both vegetation and topographical effects on the vertical and lateral water flows and the carbon cycle, is used to simulate NPP at 30 m and 1 km resolutions for a 5700 km2 watershed with an elevation range from 518 m to 3767 m in the Qinling Mountain, Shanxi Province, China. Assuming that the NPP simulated at 30 m resolution represents the reality and that at 1 km resolution is subject to errors due to sub-pixel heterogeneity, a spatial scaling index (SSI) is developed to correct the coarse resolution NPP values pixel by pixel. The agreement between the NPP values at these two resolutions is improved considerably from R2 = 0.782 to R2 = 0.884 after the correction. The mean bias error (MBE) in NPP modelled at the 1 km resolution is reduced from 14.8 g C m-2 yr-1 to 4.8 g C m-2 yr-1 in comparison with NPP modelled at 30 m resolution, where the mean NPP is 668 g C m-2 yr-1. The range of spatial variations of NPP at 30 m resolution is larger than that at 1 km resolution. Land cover fraction is the most important vegetation factor to be considered in NPP spatial scaling, and slope is the most important topographical factor for NPP spatial scaling especially in mountainous areas, because of its influence on the lateral water redistribution, affecting water table, soil moisture and plant growth. Other factors including leaf area index (LAI) and elevation have small and additive effects on improving the spatial scaling between these two resolutions.

Simulating effects of fire disturbance and climate change on boreal forest productivity and evapotranspiration.

PubMed

Kang, Sinkyu; Kimball, John S; Running, Steven W

2006-06-01

We used a terrestrial ecosystem process model, BIOME-BGC, to investigate historical climate change and fire disturbance effects on regional carbon and water budgets within a 357,500 km(2) portion of the Canadian boreal forest. Historical patterns of increasing atmospheric CO2, climate change, and regional fire activity were used as model drivers to evaluate the relative effects of these impacts to spatial patterns and temporal trends in forest net primary production (NPP) and evapotranspiration (ET). Historical trends of increasing atmospheric CO2 resulted in overall 13% and 5% increases in annual NPP and ET from 1994 to 1996, respectively. NPP was found to be relatively sensitive to changes in air temperature (T(a)), while ET was more sensitive to precipitation (P) change within the ranges of observed climate variability (e.g., +/-2 degrees C for T(a) and +/-20% for P). In addition, the potential effect of climate change related warming on NPP is exacerbated or offset depending on whether these changes are accompanied by respective decreases or increases in precipitation. Historical fire activity generally resulted in reductions of both NPP and ET, which consumed an average of approximately 6% of annual NPP from 1959 to 1996. Areas currently occupied by dry conifer forests were found to be subject to more frequent fire activity, which consumed approximately 8% of annual NPP. The results of this study show that the North American boreal ecosystem is sensitive to historical patterns of increasing atmospheric CO2, climate change and regional fire activity. The relative impacts of these disturbances on NPP and ET interact in complex ways and are spatially variable depending on regional land cover and climate gradients.

Does climate directly influence NPP globally?

PubMed

Chu, Chengjin; Bartlett, Megan; Wang, Youshi; He, Fangliang; Weiner, Jacob; Chave, Jérôme; Sack, Lawren

2016-01-01

The need for rigorous analyses of climate impacts has never been more crucial. Current textbooks state that climate directly influences ecosystem annual net primary productivity (NPP), emphasizing the urgent need to monitor the impacts of climate change. A recent paper challenged this consensus, arguing, based on an analysis of NPP for 1247 woody plant communities across global climate gradients, that temperature and precipitation have negligible direct effects on NPP and only perhaps have indirect effects by constraining total stand biomass (Mtot ) and stand age (a). The authors of that study concluded that the length of the growing season (lgs ) might have a minor influence on NPP, an effect they considered not to be directly related to climate. In this article, we describe flaws that affected that study's conclusions and present novel analyses to disentangle the effects of stand variables and climate in determining NPP. We re-analyzed the same database to partition the direct and indirect effects of climate on NPP, using three approaches: maximum-likelihood model selection, independent-effects analysis, and structural equation modeling. These new analyses showed that about half of the global variation in NPP could be explained by Mtot combined with climate variables and supported strong and direct influences of climate independently of Mtot , both for NPP and for net biomass change averaged across the known lifetime of the stands (ABC = average biomass change). We show that lgs is an important climate variable, intrinsically correlated with, and contributing to mean annual temperature and precipitation (Tann and Pann ), all important climatic drivers of NPP. Our analyses provide guidance for statistical and mechanistic analyses of climate drivers of ecosystem processes for predictive modeling and provide novel evidence supporting the strong, direct role of climate in determining vegetation productivity at the global scale. © 2015 John Wiley & Sons Ltd.

Drivers and uncertainties of future global marine primary production in marine ecosystem models

NASA Astrophysics Data System (ADS)

Laufkötter, C.; Vogt, M.; Gruber, N.; Aita-Noguchi, M.; Aumont, O.; Bopp, L.; Buitenhuis, E.; Doney, S. C.; Dunne, J.; Hashioka, T.; Hauck, J.; Hirata, T.; John, J.; Le Quéré, C.; Lima, I. D.; Nakano, H.; Seferian, R.; Totterdell, I.; Vichi, M.; Völker, C.

2015-12-01

Past model studies have projected a global decrease in marine net primary production (NPP) over the 21st century, but these studies focused on the multi-model mean rather than on the large inter-model differences. Here, we analyze model-simulated changes in NPP for the 21st century under IPCC's high-emission scenario RCP8.5. We use a suite of nine coupled carbon-climate Earth system models with embedded marine ecosystem models and focus on the spread between the different models and the underlying reasons. Globally, NPP decreases in five out of the nine models over the course of the 21st century, while three show no significant trend and one even simulates an increase. The largest model spread occurs in the low latitudes (between 30° S and 30° N), with individual models simulating relative changes between -25 and +40 %. Of the seven models diagnosing a net decrease in NPP in the low latitudes, only three simulate this to be a consequence of the classical interpretation, i.e., a stronger nutrient limitation due to increased stratification leading to reduced phytoplankton growth. In the other four, warming-induced increases in phytoplankton growth outbalance the stronger nutrient limitation. However, temperature-driven increases in grazing and other loss processes cause a net decrease in phytoplankton biomass and reduce NPP despite higher growth rates. One model projects a strong increase in NPP in the low latitudes, caused by an intensification of the microbial loop, while NPP in the remaining model changes by less than 0.5 %. While models consistently project increases NPP in the Southern Ocean, the regional inter-model range is also very substantial. In most models, this increase in NPP is driven by temperature, but it is also modulated by changes in light, macronutrients and iron as well as grazing. Overall, current projections of future changes in global marine NPP are subject to large uncertainties and necessitate a dedicated and sustained effort to improve the models and the concepts and data that guide their development.

Vegetation turnover and nitrogen feedback drive temperate forest carbon sequestration in response to elevated CO[2]. A multi-model structural analysis

NASA Astrophysics Data System (ADS)

Walker, A. P.; Zaehle, S.; Medlyn, B. E.; De Kauwe, M. G.; Asao, S.; Hickler, T.; Lomas, M. R.; Pak, B. C.; Parton, W. J.; Quegan, S.; Ricciuto, D. M.; Wang, Y.; Warlind, D.; Norby, R. J.

2013-12-01

Predicting forest carbon (C) sequestration requires understanding the processes leading to rates of biomass C accrual (net primary productivity; NPP) and loss (turnover). In temperate forest ecosystems, experiments and models have shown that feedback via progressive nitrogen limitation (PNL) is a key driver of NPP responses to elevated CO[2]. In this analysis we show that while still important, PNL may not be as severe a constraint on NPP as indicated by some studies and that the response of turnover to elevated CO[2] could be as important, especially in the near to medium term. Seven terrestrial ecosystem and biosphere models that couple C and N cycles with varying assumptions and complexity were used to simulate responses over 300 years to a step change in CO[2] to 550 ppmv. Simulations were run for the evergreen needleleaf Duke forest and the deciduous broadleaf Oak Ridge forest FACE experiments. Whether or not a model simulated PNL under elevated CO[2] depended on model structure and the timescale of observation. Avoiding PNL depended on mechanisms that reduced ecosystem N losses. The two key assumptions that reduced N losses were whether plant N uptake was based on plant N demand and whether ecosystem N losses (volatisation and leaching) were dependent on the concentration of N in the soil solution. Assumptions on allocation and turnover resulted in very different responses of turnover to elevated CO[2], which had profound implications for C sequestration. For example, at equilibrium CABLE2.0 predicted an increase in vegetation C sequestration despite decreased NPP, while O-CN predicted much less vegetation C sequestration than would be expected from predicted NPP increases alone. Generally elevated CO[2] favoured a shift in C partitioning towards longer lived wood biomass, which increased vegetation turnover and enhanced C sequestration. Enhanced wood partitioning was overlaid by increases or decreases in self-thinning depended on whether self-thinning was simply a function of forest structure, or structure and NPP. Self-thinning assumptions altered equilibrium C sequestration and were extremely important for the immediate transient response and near-term prediction of C sequestration.

Comparison of Modeling Approaches for Carbon Partitioning: Impact on Estimates of Global Net Primary Production and Equilibrium Biomass of Woody Vegetation from MODIS GPP

NASA Astrophysics Data System (ADS)

Ise, T.; Litton, C. M.; Giardina, C. P.; Ito, A.

2009-12-01

Plant partitioning of carbon (C) to above- vs. belowground, to growth vs. respiration, and to short vs. long lived tissues exerts a large influence on ecosystem structure and function with implications for the global C budget. Importantly, outcomes of process-based terrestrial vegetation models are likely to vary substantially with different C partitioning algorithms. However, controls on C partitioning patterns remain poorly quantified, and studies have yielded variable, and at times contradictory, results. A recent meta-analysis of forest studies suggests that the ratio of net primary production (NPP) and gross primary production (GPP) is fairly conservative across large scales. To illustrate the effect of this unique meta-analysis-based partitioning scheme (MPS), we compared an application of MPS to a terrestrial satellite-based (MODIS) GPP to estimate NPP vs. two global process-based vegetation models (Biome-BGC and VISIT) to examine the influence of C partitioning on C budgets of woody plants. Due to the temperature dependence of maintenance respiration, NPP/GPP predicted by the process-based models increased with latitude while the ratio remained constant with MPS. Overall, global NPP estimated with MPS was 17 and 27% lower than the process-based models for temperate and boreal biomes, respectively, with smaller differences in the tropics. Global equilibrium biomass of woody plants was then calculated from the NPP estimates and tissue turnover rates from VISIT. Since turnover rates differed greatly across tissue types (i.e., metabolically active vs. structural), global equilibrium biomass estimates were sensitive to the partitioning scheme employed. The MPS estimate of global woody biomass was 7-21% lower than that of the process-based models. In summary, we found that model output for NPP and equilibrium biomass was quite sensitive to the choice of C partitioning schemes. Carbon use efficiency (CUE; NPP/GPP) by forest biome and the globe. Values are means for 2001-2006.

Variation in stem mortality rates determines patterns of above-ground biomass in Amazonian forests: implications for dynamic global vegetation models.

PubMed

Johnson, Michelle O; Galbraith, David; Gloor, Manuel; De Deurwaerder, Hannes; Guimberteau, Matthieu; Rammig, Anja; Thonicke, Kirsten; Verbeeck, Hans; von Randow, Celso; Monteagudo, Abel; Phillips, Oliver L; Brienen, Roel J W; Feldpausch, Ted R; Lopez Gonzalez, Gabriela; Fauset, Sophie; Quesada, Carlos A; Christoffersen, Bradley; Ciais, Philippe; Sampaio, Gilvan; Kruijt, Bart; Meir, Patrick; Moorcroft, Paul; Zhang, Ke; Alvarez-Davila, Esteban; Alves de Oliveira, Atila; Amaral, Ieda; Andrade, Ana; Aragao, Luiz E O C; Araujo-Murakami, Alejandro; Arets, Eric J M M; Arroyo, Luzmila; Aymard, Gerardo A; Baraloto, Christopher; Barroso, Jocely; Bonal, Damien; Boot, Rene; Camargo, Jose; Chave, Jerome; Cogollo, Alvaro; Cornejo Valverde, Fernando; Lola da Costa, Antonio C; Di Fiore, Anthony; Ferreira, Leandro; Higuchi, Niro; Honorio, Euridice N; Killeen, Tim J; Laurance, Susan G; Laurance, William F; Licona, Juan; Lovejoy, Thomas; Malhi, Yadvinder; Marimon, Bia; Marimon, Ben Hur; Matos, Darley C L; Mendoza, Casimiro; Neill, David A; Pardo, Guido; Peña-Claros, Marielos; Pitman, Nigel C A; Poorter, Lourens; Prieto, Adriana; Ramirez-Angulo, Hirma; Roopsind, Anand; Rudas, Agustin; Salomao, Rafael P; Silveira, Marcos; Stropp, Juliana; Ter Steege, Hans; Terborgh, John; Thomas, Raquel; Toledo, Marisol; Torres-Lezama, Armando; van der Heijden, Geertje M F; Vasquez, Rodolfo; Guimarães Vieira, Ima Cèlia; Vilanova, Emilio; Vos, Vincent A; Baker, Timothy R

2016-12-01

Understanding the processes that determine above-ground biomass (AGB) in Amazonian forests is important for predicting the sensitivity of these ecosystems to environmental change and for designing and evaluating dynamic global vegetation models (DGVMs). AGB is determined by inputs from woody productivity [woody net primary productivity (NPP)] and the rate at which carbon is lost through tree mortality. Here, we test whether two direct metrics of tree mortality (the absolute rate of woody biomass loss and the rate of stem mortality) and/or woody NPP, control variation in AGB among 167 plots in intact forest across Amazonia. We then compare these relationships and the observed variation in AGB and woody NPP with the predictions of four DGVMs. The observations show that stem mortality rates, rather than absolute rates of woody biomass loss, are the most important predictor of AGB, which is consistent with the importance of stand size structure for determining spatial variation in AGB. The relationship between stem mortality rates and AGB varies among different regions of Amazonia, indicating that variation in wood density and height/diameter relationships also influences AGB. In contrast to previous findings, we find that woody NPP is not correlated with stem mortality rates and is weakly positively correlated with AGB. Across the four models, basin-wide average AGB is similar to the mean of the observations. However, the models consistently overestimate woody NPP and poorly represent the spatial patterns of both AGB and woody NPP estimated using plot data. In marked contrast to the observations, DGVMs typically show strong positive relationships between woody NPP and AGB. Resolving these differences will require incorporating forest size structure, mechanistic models of stem mortality and variation in functional composition in DGVMs. © 2016 The Authors. Global Change Biology Published by John Wiley & Sons Ltd.

International rehabilitation project for the territories contaminated as a result of the ChNPP accident

DOE Office of Scientific and Technical Information (OSTI.GOV)

Polyakov, A.S.; Raginsky, L.S.; Rybakov, K.A.

1993-12-31

The international rehabilitation project for the territories contaminated as a result of the ChNPP accident is described. The project includes the development of techniques and hardware for decontamination of soils in the suffered regions Russia, the Ukraina, and Byelorussia, in view of differences in composition of soils, their structure, landscape and geological characteristic properties.

Shifting plant species composition in response to climate change stabilizes grassland primary production.

PubMed

Liu, Huiying; Mi, Zhaorong; Lin, Li; Wang, Yonghui; Zhang, Zhenhua; Zhang, Fawei; Wang, Hao; Liu, Lingli; Zhu, Biao; Cao, Guangmin; Zhao, Xinquan; Sanders, Nathan J; Classen, Aimée T; Reich, Peter B; He, Jin-Sheng

2018-04-17

The structure and function of alpine grassland ecosystems, including their extensive soil carbon stocks, are largely shaped by temperature. The Tibetan Plateau in particular has experienced significant warming over the past 50 y, and this warming trend is projected to intensify in the future. Such climate change will likely alter plant species composition and net primary production (NPP). Here we combined 32 y of observations and monitoring with a manipulative experiment of temperature and precipitation to explore the effects of changing climate on plant community structure and ecosystem function. First, long-term climate warming from 1983 to 2014, which occurred without systematic changes in precipitation, led to higher grass abundance and lower sedge abundance, but did not affect aboveground NPP. Second, an experimental warming experiment conducted over 4 y had no effects on any aspect of NPP, whereas drought manipulation (reducing precipitation by 50%), shifted NPP allocation belowground without affecting total NPP. Third, both experimental warming and drought treatments, supported by a meta-analysis at nine sites across the plateau, increased grass abundance at the expense of biomass of sedges and forbs. This shift in functional group composition led to deeper root systems, which may have enabled plant communities to acquire more water and thus stabilize ecosystem primary production even with a changing climate. Overall, our study demonstrates that shifting plant species composition in response to climate change may have stabilized primary production in this high-elevation ecosystem, but it also caused a shift from aboveground to belowground productivity.

Validation of MCNP NPP Activation Simulations for Decommissioning Studies by Analysis of NPP Neutron Activation Foil Measurement Campaigns

NASA Astrophysics Data System (ADS)

Volmert, Ben; Pantelias, Manuel; Mutnuru, R. K.; Neukaeter, Erwin; Bitterli, Beat

2016-02-01

In this paper, an overview of the Swiss Nuclear Power Plant (NPP) activation methodology is presented and the work towards its validation by in-situ NPP foil irradiation campaigns is outlined. Nuclear Research and consultancy Group (NRG) in The Netherlands has been given the task of performing the corresponding neutron metrology. For this purpose, small Aluminium boxes containing a set of circular-shaped neutron activation foils have been prepared. After being irradiated for one complete reactor cycle, the sets have been successfully retrieved, followed by gamma-spectrometric measurements of the individual foils at NRG. Along with the individual activities of the foils, the reaction rates and thermal, intermediate and fast neutron fluence rates at the foil locations have been determined. These determinations include appropriate corrections for gamma self-absorption and neutron self-shielding as well as corresponding measurement uncertainties. The comparison of the NPP Monte Carlo calculations with the results of the foil measurements is done by using an individual generic MCNP model functioning as an interface and allowing the simulation of individual foil activation by predetermined neutron spectra. To summarize, the comparison between calculation and measurement serve as a sound validation of the Swiss NPP activation methodology by demonstrating a satisfying agreement between measurement and calculation. Finally, the validation offers a chance for further improvements of the existing NPP models by ensuing calibration and/or modelling optimizations for key components and structures.

Effects of climate change and shifts in forest composition on forest net primary production

Treesearch

Jyh-Min Chiang; Louts [Louis] R. Iverson; Anantha Prasad; Kim J. Brown

2008-01-01

Forests are dynamic in both structure and species composition, and these dynamics are strongly influenced by climate. However, the net effects of future tree species composition on net primary production (NPP) are not well understood. The objective of this work was to model the potential range shifts of tree species (DISTRIB Model) and predict their impacts on NPP (...

Evaluation of NPP-VIIRS Nighttime Light Data for Mapping Global Fossil Fuel Combustion CO2 Emissions: A Comparison with DMSP-OLS Nighttime Light Data.

PubMed

Ou, Jinpei; Liu, Xiaoping; Li, Xia; Li, Meifang; Li, Wenkai

2015-01-01

Recently, the stable light products and radiance calibrated products from Defense Meteorological Satellite Program's (DMSP) Operational Linescan System (OLS) have been useful for mapping global fossil fuel carbon dioxide (CO2) emissions at fine spatial resolution. However, few studies on this subject were conducted with the new-generation nighttime light data from the Visible Infrared Imaging Radiometer Suite (VIIRS) sensor on the Suomi National Polar-orbiting Partnership (NPP) Satellite, which has a higher spatial resolution and a wider radiometric detection range than the traditional DMSP-OLS nighttime light data. Therefore, this study performed the first evaluation of the potential of NPP-VIIRS data in estimating the spatial distributions of global CO2 emissions (excluding power plant emissions). Through a disaggregating model, three global emission maps were then derived from population counts and three different types of nighttime lights data (NPP-VIIRS, the stable light data and radiance calibrated data of DMSP-OLS) for a comparative analysis. The results compared with the reference data of land cover in Beijing, Shanghai and Guangzhou show that the emission areas of map from NPP-VIIRS data have higher spatial consistency of the artificial surfaces and exhibit a more reasonable distribution of CO2 emission than those of other two maps from DMSP-OLS data. Besides, in contrast to two maps from DMSP-OLS data, the emission map from NPP-VIIRS data is closer to the Vulcan inventory and exhibits a better agreement with the actual statistical data of CO2 emissions at the level of sub-administrative units of the United States. This study demonstrates that the NPP-VIIRS data can be a powerful tool for studying the spatial distributions of CO2 emissions, as well as the socioeconomic indicators at multiple scales.

Evaluation of NPP-VIIRS Nighttime Light Data for Mapping Global Fossil Fuel Combustion CO2 Emissions: A Comparison with DMSP-OLS Nighttime Light Data

PubMed Central

Ou, Jinpei; Liu, Xiaoping; Li, Xia; Li, Meifang; Li, Wenkai

2015-01-01

Recently, the stable light products and radiance calibrated products from Defense Meteorological Satellite Program’s (DMSP) Operational Linescan System (OLS) have been useful for mapping global fossil fuel carbon dioxide (CO2) emissions at fine spatial resolution. However, few studies on this subject were conducted with the new-generation nighttime light data from the Visible Infrared Imaging Radiometer Suite (VIIRS) sensor on the Suomi National Polar-orbiting Partnership (NPP) Satellite, which has a higher spatial resolution and a wider radiometric detection range than the traditional DMSP-OLS nighttime light data. Therefore, this study performed the first evaluation of the potential of NPP-VIIRS data in estimating the spatial distributions of global CO2 emissions (excluding power plant emissions). Through a disaggregating model, three global emission maps were then derived from population counts and three different types of nighttime lights data (NPP-VIIRS, the stable light data and radiance calibrated data of DMSP-OLS) for a comparative analysis. The results compared with the reference data of land cover in Beijing, Shanghai and Guangzhou show that the emission areas of map from NPP-VIIRS data have higher spatial consistency of the artificial surfaces and exhibit a more reasonable distribution of CO2 emission than those of other two maps from DMSP-OLS data. Besides, in contrast to two maps from DMSP-OLS data, the emission map from NPP-VIIRS data is closer to the Vulcan inventory and exhibits a better agreement with the actual statistical data of CO2 emissions at the level of sub-administrative units of the United States. This study demonstrates that the NPP-VIIRS data can be a powerful tool for studying the spatial distributions of CO2 emissions, as well as the socioeconomic indicators at multiple scales. PMID:26390037

Development of an NDA system for high-level waste from the Chernobyl new safe confinement construction site

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Sang-yoon; Browne, Michael C; Rael, Carlos D

2010-01-01

In early 2009, preliminary excavation work has begun in preparation for the construction of the New Safe Confinement (NSC) at the Chernobyl Nuclear Power Plant (ChNPP) in Ukraine. The NSC is the structure that will replace the present containment structure and will confine the radioactive remains of the ChNPP Unit-4 reactor for the next 100 years. It is expected that special nuclear material (SNM) that was ejected from the Unit-4 reactor during the accident in 1986 could be uncovered and would therefore need to be safeguarded. ChNPP requested the assistance of the United States Department of Energy/National Nuclear Security Administrationmore » (NNSA) with developing a new non-destructive assay (NDA) system that is capable of assaying radioactive debris stored in 55-gallon drums. The design of the system has to be tailored to the unique circumstances and work processes at the NSC construction site and the ChNPP. This paper describes the Chernobyl Drum Assay System (CDAS), the solution devised by Los Alamos National Laboratory, Sonalysts Inc., and the ChNPP, under NNSA's International Safeguards and Engagement Program (INSEP). The neutron counter measures the spontaneous fission neutrons from the {sup 238}U, {sup 240}Pu, {sup 244}Cm in a waste drum and estimates the mass contents of the SNMs in the drum by using of isotopic compositions determined by fuel burnup. The preliminary evaluation on overall measurement uncertainty shows that the system meets design performance requirements imposed by the facility.« less

Shifting plant species composition in response to climate change stabilizes grassland primary production

PubMed Central

Liu, Huiying; Mi, Zhaorong; Lin, Li; Wang, Yonghui; Zhang, Zhenhua; Zhang, Fawei; Wang, Hao; Liu, Lingli; Zhu, Biao; Cao, Guangmin; Zhao, Xinquan; Sanders, Nathan J.; Reich, Peter B.

2018-01-01

The structure and function of alpine grassland ecosystems, including their extensive soil carbon stocks, are largely shaped by temperature. The Tibetan Plateau in particular has experienced significant warming over the past 50 y, and this warming trend is projected to intensify in the future. Such climate change will likely alter plant species composition and net primary production (NPP). Here we combined 32 y of observations and monitoring with a manipulative experiment of temperature and precipitation to explore the effects of changing climate on plant community structure and ecosystem function. First, long-term climate warming from 1983 to 2014, which occurred without systematic changes in precipitation, led to higher grass abundance and lower sedge abundance, but did not affect aboveground NPP. Second, an experimental warming experiment conducted over 4 y had no effects on any aspect of NPP, whereas drought manipulation (reducing precipitation by 50%), shifted NPP allocation belowground without affecting total NPP. Third, both experimental warming and drought treatments, supported by a meta-analysis at nine sites across the plateau, increased grass abundance at the expense of biomass of sedges and forbs. This shift in functional group composition led to deeper root systems, which may have enabled plant communities to acquire more water and thus stabilize ecosystem primary production even with a changing climate. Overall, our study demonstrates that shifting plant species composition in response to climate change may have stabilized primary production in this high-elevation ecosystem, but it also caused a shift from aboveground to belowground productivity. PMID:29666319

Longtime variation of phytoplankton in the South China Sea from the perspective of carbon fixation

NASA Astrophysics Data System (ADS)

Li, Teng; Bai, Yan; Chen, Xiaoyan; Zhu, Qiankun; Gong, Fang; Wang, Difeng

2017-10-01

The ocean is a huge carbon pool in the earth, and about half of the anthropogenic emissions of carbon dioxide are absorbed by the ocean each year. By converting inorganic carbon into organic carbon, the photosynthesis process of phytoplankton affords an important way for carbon sequestration in the ocean. According to previous researches, primary production (NPP) and the structure of phytoplankton community are important in regulate the efficiency of biological carbon pump. This study examined the spatiotemporal variability of satellite remote sensing derived chlorophyll a concentration (Chla), phytoplankton carbon biomass (Carbon), composition ratio of micro-, nano- and pico- phytoplankton, NPP and integrated particulate organic carbon (IPOC) during 1998-2007 in the South China Sea (SCS). Micro-, nano-phytoplankton and NPP showed similar seasonal variation with highest values in winter (January) (especially in the western ocean of Luzon Strait) and lowest values in summer (July) in SCS. Chla, phytoplankton carbon biomass, and IPOC showed different seasonal trends with one peak values occurred in winter and lowest in spring. Two sampling areas (A, N:17-21°, E:117.5-120° and B, N:12.5-15°, E:112-119°) in SCS were selected based on spatial distribution of the standard deviation of research parameters mentioned above. Compared to Chla, phytoplankton carbon biomass, NPP and IPOC, the interannual changes of phytoplankton community structure were remarkable in the two areas. The fraction of micro- and nano- phytoplankton in SCS tend to rise when La Nina events occur. Our results contribute to an understanding of the response of phytoplankton to climate change in the marginal sea. To quantify the efficiency of biological carbon pump in this area, more attention should be paid to the development of remote sensing algorithms of export NPP (or POC export flux) as well as the regulate mechanism of export NPP.

Performance assessment of conventional and base-isolated nuclear power plants for earthquake and blast loadings

NASA Astrophysics Data System (ADS)

Huang, Yin-Nan

Nuclear power plants (NPPs) and spent nuclear fuel (SNF) are required by code and regulations to be designed for a family of extreme events, including very rare earthquake shaking, loss of coolant accidents, and tornado-borne missile impacts. Blast loading due to malevolent attack became a design consideration for NPPs and SNF after the terrorist attacks of September 11, 2001. The studies presented in this dissertation assess the performance of sample conventional and base isolated NPP reactor buildings subjected to seismic effects and blast loadings. The response of the sample reactor building to tornado-borne missile impacts and internal events (e.g., loss of coolant accidents) will not change if the building is base isolated and so these hazards were not considered. The sample NPP reactor building studied in this dissertation is composed of containment and internal structures with a total weight of approximately 75,000 tons. Four configurations of the reactor building are studied, including one conventional fixed-base reactor building and three base-isolated reactor buildings using Friction Pendulum(TM), lead rubber and low damping rubber bearings. The seismic assessment of the sample reactor building is performed using a new procedure proposed in this dissertation that builds on the methodology presented in the draft ATC-58 Guidelines and the widely used Zion method, which uses fragility curves defined in terms of ground-motion parameters for NPP seismic probabilistic risk assessment. The new procedure improves the Zion method by using fragility curves that are defined in terms of structural response parameters since damage and failure of NPP components are more closely tied to structural response parameters than to ground motion parameters. Alternate ground motion scaling methods are studied to help establish an optimal procedure for scaling ground motions for the purpose of seismic performance assessment. The proposed performance assessment procedure is used to evaluate the vulnerability of the conventional and base-isolated NPP reactor buildings. The seismic performance assessment confirms the utility of seismic isolation at reducing spectral demands on secondary systems. Procedures to reduce the construction cost of secondary systems in isolated reactor buildings are presented. A blast assessment of the sample reactor building is performed for an assumed threat of 2000 kg of TNT explosive detonated on the surface with a closest distance to the reactor building of 10 m. The air and ground shock waves produced by the design threat are generated and used for performance assessment. The air blast loading to the sample reactor building is computed using a Computational Fluid Dynamics code Air3D and the ground shock time series is generated using an attenuation model for soil/rock response. Response-history analysis of the sample conventional and base isolated reactor buildings to external blast loadings is performed using the hydrocode LS-DYNA. The spectral demands on the secondary systems in the isolated reactor building due to air blast loading are greater than those for the conventional reactor building but much smaller than those spectral demands associated with Safe Shutdown Earthquake shaking. The isolators are extremely effective at filtering out high acceleration, high frequency ground shock loading.

Methodology and measures for preventing unacceptable flow-accelerated corrosion thinning of pipelines and equipment of NPP power generating units

NASA Astrophysics Data System (ADS)

Tomarov, G. V.; Shipkov, A. A.; Lovchev, V. N.; Gutsev, D. F.

2016-10-01

Problems of metal flow-accelerated corrosion (FAC) in the pipelines and equipment of the condensate- feeding and wet-steam paths of NPP power-generating units (PGU) are examined. Goals, objectives, and main principles of the methodology for the implementation of an integrated program of AO Concern Rosenergoatom for the prevention of unacceptable FAC thinning and for increasing operational flow-accelerated corrosion resistance of NPP EaP are worded (further the Program). A role is determined and potentialities are shown for the use of Russian software packages in the evaluation and prediction of FAC rate upon solving practical problems for the timely detection of unacceptable FAC thinning in the elements of pipelines and equipment (EaP) of the secondary circuit of NPP PGU. Information is given concerning the structure, properties, and functions of the software systems for plant personnel support in the monitoring and planning of the inservice inspection of FAC thinning elements of pipelines and equipment of the secondary circuit of NPP PGUs, which are created and implemented at some Russian NPPs equipped with VVER-1000, VVER-440, and BN-600 reactors. It is noted that one of the most important practical results of software packages for supporting NPP personnel concerning the issue of flow-accelerated corrosion consists in revealing elements under a hazard of intense local FAC thinning. Examples are given for successful practice at some Russian NPP concerning the use of software systems for supporting the personnel in early detection of secondary-circuit pipeline elements with FAC thinning close to an unacceptable level. Intermediate results of working on the Program are presented and new tasks set in 2012 as a part of the updated program are denoted. The prospects of the developed methods and tools in the scope of the Program measures at the stages of design and construction of NPP PGU are discussed. The main directions of the work on solving the problems of flow-accelerated corrosion of pipelines and equipment in Russian NPP PGU are defined.

Effects of long-term nutrient additions on Arctic tundra, stream, and lake ecosystems: beyond NPP.

PubMed

Gough, Laura; Bettez, Neil D; Slavik, Karie A; Bowden, William B; Giblin, Anne E; Kling, George W; Laundre, James A; Shaver, Gaius R

2016-11-01

Primary producers form the base of food webs but also affect other ecosystem characteristics, such as habitat structure, light availability, and microclimate. Here, we examine changes caused by 5-30+ years of nutrient addition and resulting increases in net primary productivity (NPP) in tundra, streams, and lakes in northern Alaska. The Arctic provides an important opportunity to examine how ecosystems characterized by low diversity and low productivity respond to release from nutrient limitation. We review how responses of algae and plants affect light availability, perennial biotic structures available for consumers, oxygen levels, and temperature. Sometimes, responses were similar across all three ecosystems; e.g., increased NPP significantly reduced light to the substrate following fertilization. Perennial biotic structures increased in tundra and streams but not in lakes, and provided important new habitat niches for consumers as well as other producers. Oxygen and temperature responses also differed. Life history traits (e.g., longevity) of the primary producers along with the fate of detritus drove the responses and recovery. As global change persists and nutrients become more available in the Arctic and elsewhere, incorporating these factors as response variables will enable better prediction of ecosystem changes and feedbacks in this biome and others.

Comparison of modeling approaches for carbon partitioning: Impact on estimates of global net primary production and equilibrium biomass of woody vegetation from MODIS GPP

NASA Astrophysics Data System (ADS)

Ise, Takeshi; Litton, Creighton M.; Giardina, Christian P.; Ito, Akihiko

2010-12-01

Partitioning of gross primary production (GPP) to aboveground versus belowground, to growth versus respiration, and to short versus long-lived tissues exerts a strong influence on ecosystem structure and function, with potentially large implications for the global carbon budget. A recent meta-analysis of forest ecosystems suggests that carbon partitioning to leaves, stems, and roots varies consistently with GPP and that the ratio of net primary production (NPP) to GPP is conservative across environmental gradients. To examine influences of carbon partitioning schemes employed by global ecosystem models, we used this meta-analysis-based model and a satellite-based (MODIS) terrestrial GPP data set to estimate global woody NPP and equilibrium biomass, and then compared it to two process-based ecosystem models (Biome-BGC and VISIT) using the same GPP data set. We hypothesized that different carbon partitioning schemes would result in large differences in global estimates of woody NPP and equilibrium biomass. Woody NPP estimated by Biome-BGC and VISIT was 25% and 29% higher than the meta-analysis-based model for boreal forests, with smaller differences in temperate and tropics. Global equilibrium woody biomass, calculated from model-specific NPP estimates and a single set of tissue turnover rates, was 48 and 226 Pg C higher for Biome-BGC and VISIT compared to the meta-analysis-based model, reflecting differences in carbon partitioning to structural versus metabolically active tissues. In summary, we found that different carbon partitioning schemes resulted in large variations in estimates of global woody carbon flux and storage, indicating that stand-level controls on carbon partitioning are not yet accurately represented in ecosystem models.

Simulated and Inferred LAI, NPP, and Biomes in North America Since the Last Glacial Maximum.

NASA Astrophysics Data System (ADS)

Zajac, L. M.; Williams, J. W.; Kaplan, J.

2004-12-01

Vegetation structure and productivity are sensitive to climate change and are an important source of feedbacks to the climate system. Here we employ multiple lines of evidence to reconstruct variations in leaf area index (LAI), net primary productivity (NPP), and biomes. LAI determines the total canopy surface area available for light interception, gas exchange, and water loss, and NPP, the increase in plant carbon per unit area, measures the flux of carbon into the terrestrial biosphere. BIOME4, an equilibrium biogeography and biogeochemistry vegetation model, is used to simulate LAI, NPP, and biome distributions in North America for the past 21,000 years at 1,000-year time-steps. BIOME4 was coupled asynchronously to the Hadley Center Unified Model with a mixed-layer ocean model forced by variations in orbital boundary conditions, physiography, and atmospheric CO2 concentration (Kaplan et al. 2002). BIOME4 models LAI as a trade-off between maximizing light interception and minimizing water loss and assigns the LAI that maximizes NPP. Past LAI's and biomes, independently estimated from fossil pollen assemblages using the modern analogue technique, are compared to model results. In unglaciated eastern North America, canopy closure of the full-glacial conifer forests and woodlands in response to ameliorating climatic conditions resulted in a 80% increase in LAI's between 21 ka and 11 ka. After 8 ka, large areas of tundra and forest-tundra developed in deglaciated regions. The BIOME4 simulations show good agreement with the LAI's and biome distribution inferred from fossil pollen records. Sensitivity analyses with BIOME4 indicate that both climate and CO2 played important roles in regulating vegetation structure and productivity.

Radiation tolerance of boron doped dendritic web silicon solar cells

NASA Technical Reports Server (NTRS)

Rohatgi, A.

1980-01-01

The potential of dendritic web silicon for giving radiation hard solar cells is compared with the float zone silicon material. Solar cells with n(+)-p-P(+) structure and approximately 15% (AMl) efficiency were subjected to 1 MeV electron irradiation. Radiation tolerance of web cell efficiency was found to be at least as good as that of the float zone silicon cell. A study of the annealing behavior of radiation-induced defects via deep level transient spectroscopy revealed that E sub v + 0.31 eV defect, attributed to boron-oxygen-vacancy complex, is responsible for the reverse annealing of the irradiated cells in the temperature range of 150 to 350 C.

Controls of vegetation structure and net primary production in restored grasslands

USGS Publications Warehouse

Munson, Seth M.; Lauenroth, William K.

2014-01-01

1. Vegetation structure and net primary production (NPP) are fundamental properties of ecosystems. Understanding how restoration practices following disturbance interact with environmental factors to control these properties can provide insight on how ecosystems recover and guide management efforts. 2. We assessed the relative contribution of environmental and restoration factors in controlling vegetation structure, above- and below-ground investment in production across a chronosequence of semiarid Conservation Reserve Program (CRP) fields recovering from dryland wheat cropping relative to undisturbed grassland. Importantly, we determined the role of plant diversity and how seeding either native or introduced perennial grasses influenced the recovery of vegetation properties. 3. Plant basal cover increased with field age and was highest in CRP fields seeded with native perennial grasses. In contrast, fields seeded with introduced perennial grasses had tall-growing plants with relatively low basal cover. These vegetation structural characteristics interacted with precipitation, but not soil characteristics, to influence above-ground NPP (ANPP). Fields enrolled in the CRP program for >7 years supported twice as much ANPP as undisturbed shortgrass steppe in the first wet year of the study, but all CRP fields converged on a common low amount of ANPP in the following dry year and invested less than half as much as the shortgrass steppe in below-ground biomass. 4. ANPP in CRP fields seeded with native perennial grasses for more than 7 years was positively related to species richness, whereas ANPP in CRP fields seeded with introduced perennial grasses were controlled more by dominant species. 5. Synthesis and applications. Seeding with introduced, instead of native, perennial grasses had a strong direct influence on vegetation structure, including species richness, which indirectly affected NPP through time. However, the effects of restoring either native or introduced grasses on NPP were secondary to low water availability. Therefore, restoration strategies that maximize basal cover and below-ground biomass, which promote water acquisition, may lead to high resilience in semiarid and arid regions.

Comparing the Performance of Three Land Models in Global C Cycle Simulations: A Detailed Structural Analysis: Structural Analysis of Land Models

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rafique, Rashid; Xia, Jianyang; Hararuk, Oleksandra

Land models are valuable tools to understand the dynamics of global carbon (C) cycle. Various models have been developed and used for predictions of future C dynamics but uncertainties still exist. Diagnosing the models’ behaviors in terms of structures can help to narrow down the uncertainties in prediction of C dynamics. In this study three widely used land surface models, namely CSIRO’s Atmosphere Biosphere Land Exchange (CABLE) with 9 C pools, Community Land Model (version 3.5) combined with Carnegie-Ames-Stanford Approach (CLM-CASA) with 12 C pools and Community Land Model (version 4) (CLM4) with 26 C pools were driven by themore » observed meteorological forcing. The simulated C storage and residence time were used for analysis. The C storage and residence time were computed globally for all individual soil and plant pools, as well as net primary productivity (NPP) and its allocation to different plant components’ based on these models. Remotely sensed NPP and statistically derived HWSD, and GLC2000 datasets were used as a reference to evaluate the performance of these models. Results showed that CABLE exhibited better agreement with referenced C storage and residence time for plant and soil pools, as compared with CLM-CASA and CLM4. CABLE had longer bulk residence time for soil C pools and stored more C in roots, whereas, CLM-CASA and CLM4 stored more C in woody pools due to differential NPP allocation. Overall, these results indicate that the differences in C storage and residence times in three models are largely due to the differences in their fundamental structures (number of C pools), NPP allocation and C transfer rates. Our results have implications in model development and provide a general framework to explain the bias/uncertainties in simulation of C storage and residence times from the perspectives of model structures.« less

Thick Concrete Specimen Construction, Testing, and Preliminary Analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Clayton, Dwight A.; Hoegh, Kyle; Khazanovich, Lev

The purpose of the U.S. Department of Energy Office of Nuclear Energy’s Light Water Reactor Sustainability (LWRS) Program is to develop technologies and other solutions that can improve the reliability, sustain the safety, and extend the operating lifetimes of nuclear power plants (NPPs) beyond 60 years. Since many important safety structures in an NPP are constructed of concrete, inspection techniques must be developed and tested to evaluate the internal condition. In-service containment structures generally do not allow for the destructive measures necessary to validate the accuracy of these inspection techniques. This creates a need for comparative testing of the variousmore » nondestructive evaluation (NDE) measurement techniques on concrete specimens with known material properties, voids, internal microstructure flaws, and reinforcement locations. A preliminary report detailed some of the challenges associated with thick reinforced concrete sections and prioritized conceptual designs of specimens that could be fabricated to represent NPP concrete structures for using in NDE evaluation comparisons. This led to the construction of the concrete specimen presented in this report, which has sufficient reinforcement density and cross-sectional size to represent an NPP containment wall. Details on how a suitably thick concrete specimen was constructed are presented, including the construction materials, final nominal design schematic, as well as formwork and rigging required to safely meet the desired dimensions of the concrete structure. The report also details the type and methods of forming the concrete specimen as well as information on how the rebar and simulated defects were embedded. Details on how the resulting specimen was transported, safely anchored, and marked to allow access for systematic comparative NDE testing of defects in a representative NPP containment wall concrete specimen are also given. Data collection using the MIRA Ultrasonic NDE equipment and initial results are also presented along with a discussion of the preliminary findings. Comparative NDE of various defects in reinforced concrete specimens is a key component in identifying the most promising techniques and directing the research and development efforts needed to characterize concrete degradation in commercial NPPs. This requires access to the specimens for data collection using state-of-the-art technology. The construction of the specimen detailed in this report allows for an evaluation of how different NDE techniques may interact with the size and complexities of NPP concrete structures. These factors were taken into account when determining specimen size and features to ensure a realistic design. The lateral dimensions of the specimen were also chosen to mitigate unrealistic boundary effects that would not affect the results of field NPP concrete testing. Preliminary results show that, while the current methods are able to identify some of the deeper defects, improvements in data processing or hardware are necessary to be able to achieve the precision and reliability achieved in evaluating thinner and less heavily reinforced concrete structures.« less

Uranium speciation as a function of depth in contaminated hanford sediments--a micro-XRF, micro-XRD, and micro- and bulk-XAFS study.

PubMed

Singer, David M; Zachara, John M; Brown, Gordon E

2009-02-01

The distribution and speciation of U and Cu in contaminated vadose zone and aquifer sediments from the U.S. DOE Hanford site (300 Area) were determined using a combination of synchrotron-based micro-X-ray fluorescence (microXRF) imaging, micro-X-ray absorption near edge structure (microXANES) spectroscopy, and micro-X-ray diffraction (microXRD) techniques combined with bulk U LIII-edge X-ray absorption fine structure (XAFS) spectroscopy. Samples were collected from within the inactive North Process Pond (NPP2) at 8 ft (2.4 m, NPP2-8) depth and 12 ft (3.7 m, NPP2-12) depth in the vadose zone, and fines were isolated from turbid groundwater just below the water Table (12-14 ft, approximately 4 m, NPP2-GW). microXRF imaging, microXRD, and microXANES spectroscopy revealed two major U occurrences within the vadose and groundwater zones: (1) low to moderate concentrations of U(VI) associated with fine-textured grain coatings that were consistently found to contain clinochlore (referred to here as chlorite) observed in all three samples, and (2) U(VI)-Cu(II) hotspots consisting of micrometer-sized particles associated with surface coatings on grains of muscovite and chlorite observed in samples NPP2-8' and NPP2-GW. In the aquifer fines (NPP2-GW), these particles were identified as cuprosklodowskite (cps: Cu[(UO2)(SiO2OH)]2 x 6H2O) and metatorbernite (mtb: Cu(UO2)2(PO4)2 x 8H2O). In contrast, the U-Cu-containing particles in the vadose zone were X-ray amorphous. Analyses of U LIII-edge XAFS spectra by linear-combination fitting indicated that U speciation consisted of (1) approximately 75% uranyl sorbed to chlorite and approximately 25% mtb-like X-ray amorphous U-Cu-phosphates (8 ft depth), (2) nearly 100% sorbed uranyl (12 ft depth), and (3) approximately 70% uranyl sorbed to chlorite and approximately 30% cps/mtb (groundwater zone). These findings suggest that dissolution of U(VI)-Cu(II)-bearing solids as well as desorption of U(VI), mainly from phyllosilicates, are important persistent sources of U(VI) to the associated uranium groundwater plume in Hanford Area 300.

Shifts in biomass and productivity for a subtropical dry forest in response to simulated elevated hurricane disturbances

DOE Office of Scientific and Technical Information (OSTI.GOV)

Holm, Jennifer A.; Van Bloem, Skip J.; Larocque, Guy R.

Caribbean tropical forests are subject to hurricane disturbances of great variability. In addition to natural storm incongruity, climate change can alter storm formation, duration, frequency, and intensity. This model -based investigation assessed the impacts of multiple storms of different intensities and occurrence frequencies on the long-term dynamics of subtropical dry forests in Puerto Rico. Using the previously validated individual-based gap model ZELIG-TROP, we developed a new hurricane damage routine and parameterized it with site- and species-specific hurricane effects. A baseline case with the reconstructed historical hurricane regime represented the control condition. Ten treatment cases, reflecting plausible shifts in hurricane regimes,more » manipulated both hurricane return time (i.e. frequency) and hurricane intensity. The treatment-related change in carbon storage and fluxes were reported as changes in aboveground forest biomass (AGB), net primary productivity (NPP), and in the aboveground carbon partitioning components, or annual carbon accumulation (ACA). Increasing the frequency of hurricanes decreased aboveground biomass by between 5% and 39%, and increased NPP between 32% and 50%. Decadal-scale biomass fluctuations were damped relative to the control. In contrast, increasing hurricane intensity did not create a large shift in the long-term average forest structure, NPP, or ACA from that of historical hurricane regimes, but produced large fluctuations in biomass. Decreasing both the hurricane intensity and frequency by 50% produced the highest values of biomass and NPP. For the control scenario and with increased hurricane intensity, ACA was negative, which indicated that the aboveground forest components acted as a carbon source. However, with an increase in the frequency of storms or decreased storms, the total ACA was positive due to shifts in leaf production, annual litterfall, and coarse woody debris inputs, indicating a carbon sink into the forest over the long-term. The carbon loss from each hurricane event, in all scenarios, always recovered over sufficient time. Our results suggest that subtropical dry forests will remain resilient to hurricane disturbance. However carbon stocks will decrease if future climates increase hurricane frequency by 50% or more.« less

Shifts in biomass and productivity for a subtropical dry forest in response to simulated elevated hurricane disturbances

NASA Astrophysics Data System (ADS)

Holm, Jennifer A.; Van Bloem, Skip J.; Larocque, Guy R.; Shugart, Herman H.

2017-02-01

Caribbean tropical forests are subject to hurricane disturbances of great variability. In addition to natural storm incongruity, climate change can alter storm formation, duration, frequency, and intensity. This model-based investigation assessed the impacts of multiple storms of different intensities and occurrence frequencies on the long-term dynamics of subtropical dry forests in Puerto Rico. Using the previously validated individual-based gap model ZELIG-TROP, we developed a new hurricane damage routine and parameterized it with site- and species-specific hurricane effects. A baseline case with the reconstructed historical hurricane regime represented the control condition. Ten treatment cases, reflecting plausible shifts in hurricane regimes, manipulated both hurricane return time (i.e. frequency) and hurricane intensity. The treatment-related change in carbon storage and fluxes were reported as changes in aboveground forest biomass (AGB), net primary productivity (NPP), and in the aboveground carbon partitioning components, or annual carbon accumulation (ACA). Increasing the frequency of hurricanes decreased aboveground biomass by between 5% and 39%, and increased NPP between 32% and 50%. Decadal-scale biomass fluctuations were damped relative to the control. In contrast, increasing hurricane intensity did not create a large shift in the long-term average forest structure, NPP, or ACA from that of historical hurricane regimes, but produced large fluctuations in biomass. Decreasing both the hurricane intensity and frequency by 50% produced the highest values of biomass and NPP. For the control scenario and with increased hurricane intensity, ACA was negative, which indicated that the aboveground forest components acted as a carbon source. However, with an increase in the frequency of storms or decreased storms, the total ACA was positive due to shifts in leaf production, annual litterfall, and coarse woody debris inputs, indicating a carbon sink into the forest over the long-term. The carbon loss from each hurricane event, in all scenarios, always recovered over sufficient time. Our results suggest that subtropical dry forests will remain resilient to hurricane disturbance. However carbon stocks will decrease if future climates increase hurricane frequency by 50% or more.

Shifts in biomass and productivity for a subtropical dry forest in response to simulated elevated hurricane disturbances

DOE PAGES

Holm, Jennifer A.; Van Bloem, Skip J.; Larocque, Guy R.; ...

2017-02-07

Caribbean tropical forests are subject to hurricane disturbances of great variability. In addition to natural storm incongruity, climate change can alter storm formation, duration, frequency, and intensity. This model -based investigation assessed the impacts of multiple storms of different intensities and occurrence frequencies on the long-term dynamics of subtropical dry forests in Puerto Rico. Using the previously validated individual-based gap model ZELIG-TROP, we developed a new hurricane damage routine and parameterized it with site- and species-specific hurricane effects. A baseline case with the reconstructed historical hurricane regime represented the control condition. Ten treatment cases, reflecting plausible shifts in hurricane regimes,more » manipulated both hurricane return time (i.e. frequency) and hurricane intensity. The treatment-related change in carbon storage and fluxes were reported as changes in aboveground forest biomass (AGB), net primary productivity (NPP), and in the aboveground carbon partitioning components, or annual carbon accumulation (ACA). Increasing the frequency of hurricanes decreased aboveground biomass by between 5% and 39%, and increased NPP between 32% and 50%. Decadal-scale biomass fluctuations were damped relative to the control. In contrast, increasing hurricane intensity did not create a large shift in the long-term average forest structure, NPP, or ACA from that of historical hurricane regimes, but produced large fluctuations in biomass. Decreasing both the hurricane intensity and frequency by 50% produced the highest values of biomass and NPP. For the control scenario and with increased hurricane intensity, ACA was negative, which indicated that the aboveground forest components acted as a carbon source. However, with an increase in the frequency of storms or decreased storms, the total ACA was positive due to shifts in leaf production, annual litterfall, and coarse woody debris inputs, indicating a carbon sink into the forest over the long-term. The carbon loss from each hurricane event, in all scenarios, always recovered over sufficient time. Our results suggest that subtropical dry forests will remain resilient to hurricane disturbance. However carbon stocks will decrease if future climates increase hurricane frequency by 50% or more.« less

Light Water Reactor Sustainability Program: Survey of Models for Concrete Degradation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Spencer, Benjamin W.; Huang, Hai

Concrete is widely used in the construction of nuclear facilities because of its structural strength and its ability to shield radiation. The use of concrete in nuclear facilities for containment and shielding of radiation and radioactive materials has made its performance crucial for the safe operation of the facility. As such, when life extension is considered for nuclear power plants, it is critical to have predictive tools to address concerns related to aging processes of concrete structures and the capacity of structures subjected to age-related degradation. The goal of this report is to review and document the main aging mechanismsmore » of concern for concrete structures in nuclear power plants (NPPs) and the models used in simulations of concrete aging and structural response of degraded concrete structures. This is in preparation for future work to develop and apply models for aging processes and response of aged NPP concrete structures in the Grizzly code. To that end, this report also provides recommendations for developing more robust predictive models for aging effects of performance of concrete.« less

Inspection of Nuclear Power Plant Containment Structures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Graves, H.L.; Naus, D.J.; Norris, W.E.

1998-12-01

Safety-related nuclear power plant (NPP) structures are designed to withstand loadings from a number of low-probability external and interval events, such as earthquakes, tornadoes, and loss-of-coolant accidents. Loadings incurred during normal plant operation therefore generally are not significant enough to cause appreciable degradation. However, these structures are susceptible to aging by various processes depending on the operating environment and service conditions. The effects of these processes may accumulate within these structures over time to cause failure under design conditions, or lead to costly repair. In the late 1980s and early 1990s several occurrences of degradation of NPP structures were discoveredmore » at various facilities (e.g., corrosion of pressure boundary components, freeze- thaw damage of concrete, and larger than anticipated loss of prestressing force). Despite these degradation occurrences and a trend for an increasing rate of occurrence, in-service inspection of the safety-related structures continued to be performed in a somewhat cursory manner. Starting in 1991, the U.S. Nuclear Regulatory Commission (USNRC) published the first of several new requirements to help ensure that adequate in-service inspection of these structures is performed. Current regulatory in-service inspection requirements are reviewed and a summary of degradation experience presented. Nondestructive examination techniques commonly used to inspect the NPP steel and concrete structures to identify and quantify the amount of damage present are reviewed. Finally, areas where nondestructive evaluation techniques require development (i.e., inaccessible portions of the containment pressure boundary, and thick heavily reinforced concrete sections are discussed.« less

Alkaline sphingomyelinase (NPP7) in hepatobiliary diseases: A field that needs to be closely studied.

PubMed

Duan, Rui-Dong

2018-02-27

Alkaline sphingomyelinase cleaves phosphocholine from sphingomyelin, platelet-activating factor, lysophosphatidylcholine, and less effectively phosphatidylcholine. The enzyme shares no structure similarities with acid or neutral sphingomyelinase but belongs to ecto-nucleotide pyrophosphatase/phosphodiesterase (NPP) family and therefore is also called NPP7 nowadays. The enzyme is expressed in the intestinal mucosa in many species and additionally in human liver. The enzyme in the intestinal tract has been extensively studied but not that in human liver. Studies on intestinal alkaline sphingomyelinase show that it inhibits colonic tumorigenesis and inflammation, hydrolyses dietary sphingomyelin, and stimulates cholesterol absorption. The review aims to summarize the current knowledge on liver alkaline sphingomyelinase in human and strengthen the necessity for close study on this unique human enzyme in hepatobiliary diseases.

Leasing of Nuclear Power Plants With Using Floating Technologies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kuznetsov, Yu.N.; Gabaraev, B.A.; Reshetov, V.A.

2002-07-01

The proposal to organize and realize the international program on leasing of Nuclear Power Plant (NPP) reactor compartments is brought to the notice of potential partners. The proposal is oriented to the construction of new NPPs or to replacement of worked-out reactor units of the NPPs in operation on the sites situated near water area and to the use of afloat technologies for construction, mounting and transportation of reactor units as a Reactor Compartment Block Module (RCBM). According to the offered project the RCBM is fabricated in factory conditions at the largest Russian defense shipbuilding plant - State Unitary Enterprisemore » 'Industrial Association SEVMASHPREDPRIYATIE' (SEVMASH) in the city of Severodvinsk of the Arkhangelsk region. After completion of assembling, testing and preliminary licensing the RCBM is given buoyancy by means of hermetic sealing and using pontoons and barges. The RCBM delivery to the NPP site situated near water area is performed by sea route. The RCBM is brought to the place of its installation with the use of appropriate hydraulic structures (canals, shipping locks), then is lowered on the basement constructed beforehand and incorporated into NPP scheme, of which the components are installed in advance. Floating means can be detached from the RCBM and used repeatedly for other RCBMs. Further procedure of NPP commissioning and its operation is carried out according to traditional method by power company in the framework of RCBM leasing with enlisting the services of firm-manufacturer's specialists either to provide reactor plant operation and concomitant processes or to perform author's supervision of operation. After completion of lifetime and reactor unloading the RCBM is dismantled with using the same afloat technology and taken away from NPP site to sea area entirely, together with its structures (reactor vessel, heat exchangers, pumps, pipelines and other equipment). Then RCBM is transported by shipping route to a firm-manufacturer, for subsequent reprocessing, utilization and storage. Nuclear fuel and radioactive wastes are removed from NPP site also. Use of leasing method removes legal problems connected with the transportation of radioactive materials through state borders as the RCBM remains a property of the state-producer at all stages of its life cycle. (authors)« less

Anoxia-induced release of colloid- and nanoparticle-bound phosphorus in grassland soils.

PubMed

Henderson, R; Kabengi, N; Mantripragada, N; Cabrera, M; Hassan, S; Thompson, A

2012-11-06

Particle-facilitated transport is a key mechanism of phosphorus (P) loss in agroecosystems. We assessed contributions of colloid- and nanoparticle-bound P (nPP; 1-415 nm) to total P released from grassland soils receiving biannual poultry litter applications since 1995. In laboratory incubations, soils were subjected to 7 days of anoxic conditions or equilibrated at pH 6 and 8 under oxic conditions and then the extract was size fractionated by differential centrifugation/ultrafiltration for analysis of P, Al, Fe, Si, Ti, and Ca. Selected samples were characterized by transmission electron microscopy-energy dispersive spectroscopy (TEM-EDS) and field flow fractionation (FFF-ICP-MS). Particles released were present as nanoaggregates with a mean diameter of 200-250 nm, composed of ~50-nm aluminosilicate flakes studded with Fe and Ti-rich clusters (<10 nm) that contained most of the P detected by EDS. Anoxic incubation of stimulated nPP release with seasonally saturated soils released more nPP and Fe(2+)(aq) than well-drained soils; whereas, nonreductive particle dispersion, accomplished by raising the pH, yielded no increase in nPP release. This suggests Fe acts as a cementing agent, binding to the bulk soil P-bearing colloids that can be released during reducing conditions. Furthermore, it suggests prior periodic exposure to anoxic conditions increases susceptibility to redox-induced P mobilization.

The problems of using a high-temperature sodium coolant in nuclear power plants for the production of hydrogen and other innovative applications

NASA Astrophysics Data System (ADS)

Sorokin, A. P.; Alexeev, V. V.; Kuzina, Ju. A.; Konovalov, M. A.

2017-11-01

The intensity of the hydrogen sources arriving from the third contour of installation in second in comparison with the hydrogen sources on NPP BN-600 increases by two - three order at using of high-temperature nuclear power plants with the sodium coolant (HT-NPP) for drawing of hydrogen and other innovative applications (gasification and a liquefaction of coal, profound oil refining, transformation of biomass to liquid fuel, in the chemical industry, metallurgy, the food-processing industry etc.). For these conditions basic new technological solutions are offered. The main condition of their implementation is raise of hydrogen concentration in the sodium coolant on two - three order in comparison with the modern NPP, in a combination to hydrogen removal from sodium and its pumping out through membranes from vanadium or niobium. The researches with use diffusive model have shown possibility to expel a casium inflow in sodium through a leakproof shell of fuel rods if vary such parameters as a material of fuel rods shell, its thickness and maintenance time at design of fuel rods for high-temperature NPP. However maintenance of high-temperature NPP in the presence of casium in sodium is inevitable at loss of leakproof of a fuel rods shell. In these conditions for minimisation of casium diffusion in structural materials it is necessary to provide deep clearing of sodium from cesium.

Biochemical and molecular characterization of a novel choline-specific glycerophosphodiester phosphodiesterase belonging to the nucleotide pyrophosphatase/phosphodiesterase family.

PubMed

Sakagami, Hideki; Aoki, Junken; Natori, Yumiko; Nishikawa, Kiyotaka; Kakehi, Yoshiyuki; Natori, Yasuhiro; Arai, Hiroyuki

2005-06-17

Nucleotide pyrophosphatases/phosphodiesterases (NPPs) are ubiquitous membrane-associated or secreted ectoenzymes that release nucleoside 5'-monophosphate from a variety of nucleotides and nucleotide derivatives. The mammalian NPP family comprises seven members, but only three of these (NPP1-3) have been studied in some detail. Previously we showed that lysophospholipase D, which hydrolyzes lysophosphatidylcholine (LPC) to produce lysophosphatidic acid, is identical to NPP2. More recently an uncharacterized novel NPP member (NPP7) was shown to have alkaline sphingomyelinase activity. These findings raised the possibility that other members of the NPP family act on phospholipids. Here we show that the sixth member of the NPP family, NPP6, is a choline-specific glycerophosphodiester phosphodiesterase. The sequence of NPP6 encodes a transmembrane protein containing an NPP domain with significant homology to NPP4, NPP5, and NPP7/alkaline sphingomyelinase. When expressed in HeLa cells, NPP6 was detected in both the cells and the cell culture medium as judged by Western blotting and by enzymatic activity. Recombinant NPP6 efficiently hydrolyzed the classical substrate for phospholipase C, p-nitrophenyl phosphorylcholine, but not the classical nucleotide phosphodiesterase substrate, p-nitrophenyl thymidine 5'-monophosphate. In addition, NPP6 hydrolyzed LPC to form monoacylglycerol and phosphorylcholine but not lysophosphatidic acid, showing it has a lysophospholipase C activity. NPP6 showed a preference for LPC with short (12:0 and 14:0) or polyunsaturated (18:2 and 20:4) fatty acids. It also hydrolyzed glycerophosphorylcholine and sphingosylphosphorylcholine efficiently. In mice, NPP6 mRNA was predominantly detected in kidney with a lesser expression in brain and heart, and in human it was detected in kidney and brain. The present results suggest that NPP6 has a specific role through the hydrolysis of polyunsaturated LPC, glycerophosphorylcholine, or sphingosylphosphorylcholine in these organs.

Application of laser-induced breakdown spectroscopy to zirconium in aqueous solution

NASA Astrophysics Data System (ADS)

Ruas, Alexandre; Matsumoto, Ayumu; Ohba, Hironori; Akaoka, Katsuaki; Wakaida, Ikuo

2017-05-01

In the context of the Fukushima Dai-ichi Nuclear Power Plant (F1-NPP) decommissioning process, laser-induced breakdown spectroscopy (LIBS) has many advantages. The purpose of the present work is to demonstrate the on-line monitoring capability of the LIBS coupled with the ultra-thin liquid jet sampling method. The study focuses on zirconium in aqueous solution, considering that it is a major element in the F1-NPP fuel debris that has been subject to only a few LIBS studies in the past. The methodology of data acquisition and processing are described. In particular, two regions of interest with many high intensity zirconium lines have been observed around 350 nm in the case of the ionic lines and 478 nm in the case of atomic lines. The best analytical conditions for zirconium are different depending on the analysis of ionic lines or atomic lines. A low LOD of about 4 mg L- 1 could be obtained, showing that LIBS coupled with the ultra-thin liquid jet sampling technique is a promising alternative for more complex solutions found in the F1-NPP, namely mixtures containing zirconium.

Progress in Decommissioning of Ignalina NPP Unit 1

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ancius, Darius; Krenevicius, Rimantas; Kutas, Saulius

2002-07-01

The aim of the paper is to present the Lithuanian legal framework regarding the nuclear safety in Decommissioning and Waste Management, and the progress in the Decommissioning Programme of the unit 1 of Ignalina Nuclear Power Plant (INPP). INPP is the only nuclear plant in Lithuania. It comprises two RBMK-1500 reactors. After Lithuania has restored its independence, responsibility for Ignalina NPP was transferred to the Republic of Lithuania. To ensure the control of the Nuclear Safety in Lithuania, The State Nuclear Power Safety Inspectorate (VATESI) was created on 18 October 1991, by a resolution of the Lithuanian Government. Significant workmore » has been performed over the last decade, aiming at upgrading the safety level of the Ignalina NPP with reference to the International standards. On 5 October 1999 the Seimas (Parliament) adopted the National Energy Strategy: It has been decided that unit 1 of Ignalina NPP will be closed down before 2005, The conditions and precise final date of the decommissioning of Unit 2 will be stated in the updated National Energy strategy in 2004. On 20-21 June 2000, the International Donors' Conference for the Decommissioning of Ignalina NPP took place in Vilnius. More than 200 Millions Euro were pledged of which 165 M funded directly from the European Union's budget, as financial support to the Decommissioning projects. The Decommissioning Program encompasses legal, organizational, financial and technical means including the social and economical impacts in the region of Ignalina. The Program is financed from International Support Fund, State budget, National Decommissioning Fund of Ignalina NPP and other funds. Decommissioning of Ignalina NPP is subject to VATESI license according to the Law on Nuclear Energy. The Government established the licensing procedure in the so-called 'Procedure for licensing of Nuclear Activities'; and the document 'General Requirements for Decommissioning of the Ignalina NPP' has been issued by VATESI. A very important issue is the technical support to VATESI and the Lithuanian TSO's (Technical Support Organisations) in their activities within the licensing process related to the Decommissioning of INPP. This includes regulatory assistance in the preparation of decommissioning and radioactive waste management regulatory documents, and technical assistance in the review of the safety case presented by the operator. The Institute for Radioprotection and Nuclear Safety (IRSN, France) and the French Nuclear Safety Authority (DSIN) as well as Swedish International Project (SIP) are providing their support to VATESI in these areas. (authors)« less

Status and Prospects for Low-Light Visible Sensing from the VIIRS Day/Night Band on Suomi NPP and JPSS-1

NASA Astrophysics Data System (ADS)

Miller, S. D.; Seaman, C.; Combs, C.; Solbrig, J. E.; Straka, W. C.; Walther, A.; NOH, Y. J.; Heidinger, A.

2016-12-01

Since its launch in October 2011, the Visible/Infrared Imaging Radiometer Suite (VIIRS) Day/Night Band (DNB) on the Suomi National Polar-orbiting Partnership (S-NPP) satellite has delivered above and beyond expectations, revolutionizing our ability to observe and characterize the nocturnal environment. Taking advantage of natural and artificial (man-made) light sources, the DNB offers unique information content ranging from the surface to the upper atmosphere. Notable developments include the quantitative use of moonlight for cloud property retrievals and the discovery of nightglow sensitivity revealing the signatures of gravity waves. The DNB represents a remarkable advance to the heritage low-light visible sensing of the Operational Linescan System (OLS), providing spatial and radiometric resolution unprecedented to the space platform. Soon, we will have yet another dimension of resolution to consider—temporal. In early 2017, NOAA's Joint Polar Satellite System-1 (J1) will join S-NPP in early afternoon (1330 local time, ascending node) sun-synchronous orbital plane, displaced ½ orbit ( 50 min) from S-NPP. Having two DNB sensors will offer an expanded ability (lower latitudes) to examine the temporal properties of various light sources, track the motion of ships, low-level clouds and dust storms, fire line evolution, cloud optical properties, and even the dynamics of mesospheric gravity wave structures such as thunderstorm-induced concentric gravity waves and mesospheric bores. This presentation will provide an update to the science and application-oriented research involving the S-NPP/DNB, examples of key capabilities, first results of lunar irradiance model validation, and a look ahead toward the new research opportunities to be afforded by tandem S-NPP/J1 observations. The AGU is well-positioned for anticipating these capabilities "on the eve" of the J1 launch.

Policy shifts influence the functional changes of the CNH systems on the Mongolian plateau

NASA Astrophysics Data System (ADS)

Chen, Jiquan; John, Ranjeet; Shao, Changliang; Fan, Yi; Zhang, Yaoqi; Amarjargal, Amartuvshin; Brown, Daniel G.; Qi, Jiaguo; Han, Juanjuan; Lafortezza, Raffaele; Dong, Gang

2015-08-01

By applying the concept of the coupled natural and human system (CNH), we compared spatiotemporal changes in livestock (LSK), land cover, and ecosystem production to understand the relative roles that natural and social driving forces have on CNH dynamics on the Mongolia plateau. We used socioeconomic and physical data at prefecture level for Inner Mongolia and Mongolia from 1981 through 2010 to represent changes in net primary productivity (NPP), enhanced vegetation index (EVI), precipitation, annual average temperature, LSK, livestock density (LSKD), land cover change (LCC), gross domestic production (GDP), and population (POP). The ratios such as LSK:NPP, LSKD: EVI, LSKD:albedo, LSK:POP, and LSK:GDP were examined and compared between Inner Mongolia and Mongolia, and structural equation modeling (SEM) was applied to quantify the complex interactions. Substantial differences in LSK, POP, and economic development were found among the biomes and between Inner Mongolia and Mongolia. When various indicators for policy shifts—such as the World Trade Organization (WTO) for China, the Third Campaign to Reclaim Abandoned Agriculture Lands (ATAR-3), and the Grain for Green Program for China (GFG)—were added into our SEM, the results showed significant change in the strength of the above relationships. After China joined the WTO, the relationships in Inner Mongolia between LSKD:LCC and LSKD:NPP were immensely strengthened, whereas relationships in NPP:LCC were weakened. In Mongolia, the ATAR-3 program first appeared to be an insignificant policy, but the Collapse of the Soviet Union enhanced the correlation between LSKD:LCC, weakened the connection of LCC:NPP, and did not affect LSKD:NPP. We conclude that human influences on the Mongolian CNH system exceeded those of the biophysical changes, but that the significance varies in time and per biome, as well as between Inner Mongolia and Mongolia.

QUANTIFYING UNCERTAINTY IN NET PRIMARY PRODUCTION MEASUREMENTS

EPA Science Inventory

Net primary production (NPP, e.g., g m-2 yr-1), a key ecosystem attribute, is estimated from a combination of other variables, e.g. standing crop biomass at several points in time, each of which is subject to errors in their measurement. These errors propagate as the variables a...

Imidazopyridine- and purine-thioacetamide derivatives: potent inhibitors of nucleotide pyrophosphatase/phosphodiesterase 1 (NPP1).

PubMed

Chang, Lei; Lee, Sang-Yong; Leonczak, Piotr; Rozenski, Jef; De Jonghe, Steven; Hanck, Theodor; Müller, Christa E; Herdewijn, Piet

2014-12-11

Nucleotide pyrophosphatase/phosphodiesterase 1 (NPP1) belongs to the family of ecto-nucleotidases, which control extracellular nucleotide, nucleoside, and (di)phosphate levels. To study the (patho)physiological roles of NPP1 potent and selective inhibitors with drug-like properties are required. Therefore, a compound library was screened for NPP1 inhibitors using a colorimetric assay with p-nitrophenyl 5'-thymidine monophosphate (p-Nph-5'-TMP) as an artificial substrate. This led to the discovery of 2-(3H-imidazo[4,5-b]pyridin-2-ylthio)-N-(3,4-dimethoxyphenyl)acetamide (5a) as a hit compound with a Ki value of 217 nM. Subsequent structure-activity relationship studies led to the development of purine and imidazo[4,5-b]pyridine analogues with high inhibitory potency (Ki values of 5.00 nM and 29.6 nM, respectively) when assayed with p-Nph-5'-TMP as a substrate. Surprisingly, the compounds were significantly less potent when tested versus ATP as a substrate, with Ki values in the low micromolar range. A prototypic inhibitor was investigated for its mechanism of inhibition and found to be competitive versus both substrates.

Monitoring of spatiotemporal patterns of Net and Gross Primary Productivity (NPP & GPP) and their ratios (NPP/GPP) derived from MODIS data: assessment natural drivers and their effects on NDVI anomalies in arid and semi-arid zones of Central Asia.

NASA Astrophysics Data System (ADS)

Aralova, Dildora; Jarihani, Ben; Khujanazarov, Timur; Toderich, Kristina; Gafurov, Dilshod; Gismatulina, Liliya

2017-04-01

Previous studies have shown that precipitation anomalies and raising of temperature trends were deteriorate affected on large-scale of vegetation surveys in Central Asia (CA). Nowadays, remote sensing techniques can provide estimation of Net and Gross Primary Productivity (NPP & GPP) for regional and global scales, and selected zones in CA (Kazakhstan, Kyrgyzstan, Tajikistan, Turkmenistan and Uzbekistan) dominated by C4 plants (biomes) what it reveals more accurately simulate C4 carbon. The estimation of NPP & GPP from source (MOD17A2/A3) would be beneficial to determine natural driver factors, whether on rangeland ecosystem is a carbon sink or source, such as a vast area of the selected zones incorporates exacerbate regional drought-risk factors nowadays. Generally, we have combined last available NPP & GPP (2000-2015) with 1 km resolution from MODIS, with investigation of long-term vegetation patterns under Normalized Difference Vegetation Indices (NDVI) with 8 km resolution from AVHRR-GIMMS 3g sources (2001-2015) within aim to estimate potential values of rangeland ecosystems. Interaction ratios of NPP/GPP are integrating more accurately describe carbon sink process under natural or anthropogenic factors, specifically last results of NDVI trends were described as decreasing trends due to climate anomalies, besides the eastern and northern parts of CA (mostly boreal forest zones) where accumulated or indicated of raising trends of NDVI in last three years (2012-2015). Results revealed that, in CA were averaged annually value NDVI ranges from 0.19-0.21; (Kyrgyzstan: 0.23-0.26; Kazakhstan: 0.21-0.24; Tajikistan: 0.19-0.21); and resting countries as low NDVI accumulated areas were Turkmenistan and Uzbekistan ranges 0.13-0.16; Comparing datasets of GPP given the response dynamic change structures of NDVI values and explicit carbon uptake (CO2) in arid ecosystems and average GPPyearlyin CA ranges 2.42 kg C/m2; including to Tajikistan, Uzbekistan (3.09 kg C/m2) and Turkmenistan (3.59 kg C/m2); Kazakhstan and Kyrgyzstan 0.88 & 1.46 kg C /m2. The ratings of dynamical GPP & NPP were similar for each 5 years (2000-2005, 2005-2010 and 2010-2015) and ranges GPP ≈ 2.42 kg C/m2 and NPP ≈ 2.36 kg C/m2. NPP is more accuracy in desert zones, basically, the bare areas shown a high values. The results shown that meanwhile values of NPP/GPP is relatively illustrated same results as NDVI annual trends, and NPP/GPP average value of 1.03, and incorporating well for sparsely vegetated ecosystems of CA. MODIS derived primary production datasets could improve a better estimate ecosystem process and vegetation/carbon change anomalies during water-stressed conditions in the regional level.

Net Primary Productivity and Edaphic Fertility in Two Pluvial Tropical Forests in the Chocó Biogeographical Region of Colombia

PubMed Central

Quinto-Mosquera, Harley

2017-01-01

The net primary productivity (NPP) of tropical forests is a key process of the carbon cycle and therefore for the mitigation of global climate change. It has been proposed that NPP is limited by the availability of soil nutrients in lowland tropical forests and that belowground NPP decreases as edaphic fertility increases. This hypothesis was evaluated in two localities (Opogodó and Pacurita) of the Chocó Biogeographical region, one of the rainiest of the world, where the aboveground (litter and wood) and belowground (fine and coarse roots) components of NPP were measured. Fertility parameters (pH, nutrients, and texture) were also determined and related to NPP. Total NPP was similar between locations (23.7 vs. 24.2 t ha-1 year-1 for Opogodó and Pacurita, respectively). However, components of NPP showed differences: in Pacurita, with steeper topography, NPP of wood and coarse roots were higher; therefore, differences of topography and drainage between localities probably affected the NPP of wood. On the other hand, soils of Opogodó, where NPP of fine roots was higher, showed higher contents of sand, N+, and organic matter (OM). With the increase of pH, OM, N+, K, Mg, and sand, the NPP of leaves and fine roots as well as the percentage of NPP belowground also increased, which suggests NPP limitation by multiple nutrients. The increase of NPP belowground with the availability of edaphic nutrients evidenced a redistribution of the aboveground and belowground components of NPP with the increase of soil fertility in oligotrophic systems, probably as a mechanism to improve the capture of resources. PMID:28114418

Net Primary Productivity and Edaphic Fertility in Two Pluvial Tropical Forests in the Chocó Biogeographical Region of Colombia.

PubMed

Quinto-Mosquera, Harley; Moreno, Flavio

2017-01-01

The net primary productivity (NPP) of tropical forests is a key process of the carbon cycle and therefore for the mitigation of global climate change. It has been proposed that NPP is limited by the availability of soil nutrients in lowland tropical forests and that belowground NPP decreases as edaphic fertility increases. This hypothesis was evaluated in two localities (Opogodó and Pacurita) of the Chocó Biogeographical region, one of the rainiest of the world, where the aboveground (litter and wood) and belowground (fine and coarse roots) components of NPP were measured. Fertility parameters (pH, nutrients, and texture) were also determined and related to NPP. Total NPP was similar between locations (23.7 vs. 24.2 t ha-1 year-1 for Opogodó and Pacurita, respectively). However, components of NPP showed differences: in Pacurita, with steeper topography, NPP of wood and coarse roots were higher; therefore, differences of topography and drainage between localities probably affected the NPP of wood. On the other hand, soils of Opogodó, where NPP of fine roots was higher, showed higher contents of sand, N+, and organic matter (OM). With the increase of pH, OM, N+, K, Mg, and sand, the NPP of leaves and fine roots as well as the percentage of NPP belowground also increased, which suggests NPP limitation by multiple nutrients. The increase of NPP belowground with the availability of edaphic nutrients evidenced a redistribution of the aboveground and belowground components of NPP with the increase of soil fertility in oligotrophic systems, probably as a mechanism to improve the capture of resources.

NPOESS Preparatory Project (NPP) Science Overview

NASA Technical Reports Server (NTRS)

Butler, James J.

2011-01-01

NPP Instruments are: (1) well understood thanks to instrument comprehensive test, characterization and calibration programs. (2) Government team ready for October 25 launch followed by instrument activation and Intensive Calibration/Validation (ICV). NPP Data Products preliminary work includes: (1) JPSS Center for Satellite Applications and Research (STAR) team ready to support NPP ICV and operational data products. (2) NASA NPP science team ready to support NPP ICV and EOS data continuity.

N-Glycomic and Microscopic Subcellular Localization Analyses of NPP1, 2 and 6 Strongly Indicate that trans-Golgi Compartments Participate in the Golgi to Plastid Traffic of Nucleotide Pyrophosphatase/Phosphodiesterases in Rice

PubMed Central

Kaneko, Kentaro; Takamatsu, Takeshi; Inomata, Takuya; Oikawa, Kazusato; Itoh, Kimiko; Hirose, Kazuko; Amano, Maho; Nishimura, Shin-Ichiro; Toyooka, Kiminori; Matsuoka, Ken; Pozueta-Romero, Javier; Mitsui, Toshiaki

2016-01-01

Nucleotide pyrophosphatase/phosphodiesterases (NPPs) are widely distributed N-glycosylated enzymes that catalyze the hydrolytic breakdown of numerous nucleotides and nucleotide sugars. In many plant species, NPPs are encoded by a small multigene family, which in rice are referred to NPP1–NPP6. Although recent investigations showed that N-glycosylated NPP1 is transported from the endoplasmic reticulum (ER)–Golgi system to the chloroplast through the secretory pathway in rice cells, information on N-glycan composition and subcellular localization of other NPPs is still lacking. Computer-assisted analyses of the amino acid sequences deduced from different Oryza sativa NPP-encoding cDNAs predicted all NPPs to be secretory glycoproteins. Confocal fluorescence microscopy observation of cells expressing NPP2 and NPP6 fused with green fluorescent protein (GFP) revealed that NPP2 and NPP6 are plastidial proteins. Plastid targeting of NPP2–GFP and NPP6–GFP was prevented by brefeldin A and by the expression of ARF1(Q71L), a dominant negative mutant of ADP-ribosylation factor 1 that arrests the ER to Golgi traffic, indicating that NPP2 and NPP6 are transported from the ER–Golgi to the plastidial compartment. Confocal laser scanning microscopy and high-pressure frozen/freeze-substituted electron microscopy analyses of transgenic rice cells ectopically expressing the trans-Golgi marker sialyltransferase fused with GFP showed the occurrence of contact of Golgi-derived membrane vesicles with cargo and subsequent absorption into plastids. Sensitive and high-throughput glycoblotting/mass spectrometric analyses showed that complex-type and paucimannosidic-type glycans with fucose and xylose residues occupy approximately 80% of total glycans of NPP1, NPP2 and NPP6. The overall data strongly indicate that the trans-Golgi compartments participate in the Golgi to plastid trafficking and targeting mechanism of NPPs. PMID:27335351

[Estimation of net primary productivity in arid region based on coupling model.

PubMed

Yang, Hui Jin; Li, Xiao Yu; Liu, Li Juan; Ma, Jin Long; Wang, Jin

2016-06-01

Net primary productivity (NPP), as the base for the research of matter recycling and energy flow in terrestrial ecosystem, is sensitive to the changes of environment and climate in arid region, and also is an important indicator of eco-environmental characteristics. Based on remote sensing (RS) and geographic information system (GIS), using meteorological data, eddy cova-riance data, Landsat 8 and MODIS data, this study coupled SEBAL model and light utility efficiency model to estimate the NPP of vegetation in Manas River Watershed, and the spatial pattern of NPP and the relationships between NPP and terrain factors (elevation and slope) were analyzed. Results showed that the estimated result of NPP in Manas River Watershed by coupling model was reasonable and could actually reflect the NPP of vegetation. The total annual NPP of vegetation and the mean annual NPP in Manas River Watershed in 2013 were 7066.72 Tg C·a -1 and 278.06 g C·m -2 ·a -1 respectively. With the variation of geomorphic type and land cover, the NPP changed remarkably from south to north in a trend of increase-decrease-increase-decrease pattern. The temporal variations of NPP were also obvious, with the NPP in July and August accounting for 52.2% of total annual NPP. With the increase of the elevation and slope, the mean annual NPP decreased as a whole with fluctuations induced by different land covers and environmental factors.

Exploring the response of net primary productivity variations to urban expansion and climate change: a scenario analysis for Guangdong Province in China.

PubMed

Pei, Fengsong; Li, Xia; Liu, Xiaoping; Lao, Chunhua; Xia, Gengrui

2015-03-01

Urban land development alters landscapes and carbon cycle, especially net primary productivity (NPP). Despite projections that NPP is often reduced by urbanization, little is known about NPP changes under future urban expansion and climate change conditions. In this paper, terrestrial NPP was calculated by using Biome-BGC model. However, this model does not explicitly address urban lands. Hence, we proposed a method of NPP-fraction to detect future urban NPP, assuming that the ratio of real NPP to potential NPP for urban cells remains constant for decades. Furthermore, NPP dynamics were explored by integrating the Biome-BGC and the cellular automata (CA), a widely used method for modeling urban growth. Consequently, urban expansion, climate change and their associated effects on the NPP were analyzed for the period of 2010-2039 using Guangdong Province in China as a case study. In addition, four scenarios were designed to reflect future conditions, namely baseline, climate change, urban expansion and comprehensive scenarios. Our analyses indicate that vegetation NPP in urban cells may increase (17.63 gC m(-2) year(-1)-23.35 gC m(-2) year(-1)) in the climate change scenario. However, future urban expansion may cause some NPP losses of 241.61 gC m(-2) year(-1), decupling the NPP increase of the climate change factor. Taking into account both climate change and urban expansion, vegetation NPP in urban area may decrease, minimally at a rate of 228.54 gC m(-2) year(-1) to 231.74 gC m(-2) year(-1). Nevertheless, they may account for an overall NPP increase of 0.78 TgC year(-1) to 1.28 TgC year(-1) in the whole province. All these show that the provincial NPP increase from climate change may offset the NPP decrease from urban expansion. Despite these results, it is of great significance to regulate reasonable expansion of urban lands to maintain carbon balance. Copyright © 2014 Elsevier Ltd. All rights reserved.

Phytoplankton absorption predicts patterns in primary productivity in Australian coastal shelf waters

NASA Astrophysics Data System (ADS)

Robinson, C. M.; Cherukuru, N.; Hardman-Mountford, N. J.; Everett, J. D.; McLaughlin, M. J.; Davies, K. P.; Van Dongen-Vogels, V.; Ralph, P. J.; Doblin, M. A.

2017-06-01

The phytoplankton absorption coefficient (aPHY) has been suggested as a suitable alternate first order predictor of net primary productivity (NPP). We compiled a dataset of surface bio-optical properties and phytoplankton NPP measurements in coastal waters around Australia to examine the utility of an in-situ absorption model to estimate NPP. The magnitude of surface NPP (0.20-19.3 mmol C m-3 d-1) across sites was largely driven by phytoplankton biomass, with higher rates being attributed to the microplankton (>20 μm) size class. The phytoplankton absorption coefficient aPHY for PAR (photosynthetically active radiation; āPHY)) ranged from 0.003 to 0.073 m-1, influenced by changes in phytoplankton community composition, physiology and environmental conditions. The aPHY coefficient also reflected changes in NPP and the absorption model-derived NPP could explain 73% of the variability in measured surface NPP (n = 41; RMSE = 2.49). The absorption model was applied to two contrasting coastal locations to examine NPP dynamics: a high chlorophyll-high variation (HCHV; Port Hacking National Reference Station) and moderate chlorophyll-low variation (MCLV; Yongala National Reference Station) location in eastern Australia using the GIOP-DC satellite aPHY product. Mean daily NPP rates between 2003 and 2015 were higher at the HCHV site (1.71 ± 0.03 mmol C m-3 d-1) with the annual maximum NPP occurring during the austral winter. In contrast, the MCLV site annual NPP peak occurred during the austral wet season and had lower mean daily NPP (1.43 ± 0.03 mmol C m-3 d-1) across the time-series. An absorption-based model to estimate NPP is a promising approach for exploring the spatio-temporal dynamics in phytoplankton NPP around the Australian continental shelf.

The NPOESS Community Collaborative Calibration/Validation Program for the NPOESS Preparatory Project

NASA Astrophysics Data System (ADS)

Kilcoyne, H.; Feeley, J.; Guenther, B.; Hoffman, C. W.; Reed, B.; St. Germain, K.; Zhou, L.; Plonski, M.; Hauss, B.

2009-12-01

The National Polar-orbiting Operational Environmental Satellite System (NPOESS) Preparatory Project (NPP) Calibration and Validation (Cal/Val) team is currently executing pre-launch activities and planning post-launch activities to efficiently integrate the NPOESS Sensor Data Records (SDRs) and Environmental Data Records (EDRs) into Customer applications to reduce risk in achieving NPOESS Mission Success. The NPP Cal/Val Team, led by the Integrated Program Office (IPO), includes members from the Contractor team producing the data products and subject matter experts from the Customer and User communities, bringing together the expertise with the production algorithms, product use, and science community. This presentation will highlight the progress made in the past year in defining the post-launch activity schedule, involvement of the science and operational data users, and techniques and correlative data used.

North Anna Nuclear Power Plant Strong Motion Records of the Mineral, Virginia Earthquake of August 23, 2011

NASA Astrophysics Data System (ADS)

Graizer, V.

2012-12-01

The MW 5.8 Mineral, Virginia earthquake was recorded at a relatively short epicentral distance of about 18 km at the North Anna Nuclear Power Plant (NPP) by the SMA-3 magnetic tape digital accelerographs installed inside the plant's containment at the foundation and deck levels. The North Anna NPP is operated by the Virginia Electric and Power Company (VEPCO) and has two pressurized water reactors (PWR) units that began operation in 1978 and 1980, respectively. Following the earthquake, both units were safely shutdown. The strong-motion records were processed to get velocity, displacement, Fourier and 5% damped response spectra. The basemat record demonstrated relatively high amplitudes of acceleration of 0.26 g and velocity of 13.8 cm/sec with a relatively short duration of strong motion of 2-3 sec. Recorded 5% damped Response Spectra exceed Design Basis Earthquake for the existing Units 1 and 2, while comprehensive plant inspections performed by VEPCO and U.S. Nuclear Regulatory Commission have concluded that the damage to the plant was minimal not affecting any structures and equipment significant to plant operation. This can be explained in part by short duration of the earthquake ground motion at the plant. The North Anna NPP did not have free-field strong motion instrumentation at the time of the earthquake. Since the containment is founded on rock there is a tendency to consider basemat record as an approximation of the free-field recording. However, comparisons of deck and basemat records demonstrate that the basemat recording is also affected by structural resonance frequencies higher than 3 Hz. Structural resonances in the frequency range of 3-4 Hz can at least partially explain significant exceedance of observed motions relative to ground motion calculated using ground motion prediction equations.cceleration, velocity and displacement at the North Anna NPP basemat level. Amplitudes of acceleration, velocity and displacement at basemat and deck levels

Managing nuclear power plant induced disasters.

PubMed

Kyne, Dean

2015-01-01

To understand the management process of nuclear power plant (NPP) induced disasters. The study shields light on phases and issues associated with the NPP induced disaster management. This study uses Palo Verde Nuclear Generation Station as study subject and Arizona State as study area. This study uses the Radiological Assessment System for Consequence Analysis (RASCAL) Source Term to Dose (STDose) of the Nuclear Regulatory Commission, a computer software to project and assess the source term dose and release pathway. This study also uses ArcGIS, a geographic information system to analyze geospatial data. A detailed case study of Palo Verde Nuclear Power Generation (PVNPG) Plant was conducted. The findings reveal that the NPP induced disaster management process is conducted by various stakeholders. To save lives and to minimize the impacts, it is vital to relate planning and process of the disaster management. Number of people who expose to the radioactive plume pathway and level of radioactivity could vary depending on the speed and direction of wind on the day the event takes place. This study findings show that there is a need to address the burning issue of different racial and ethnic groups' unequal exposure and unequal protection to potential risks associated with the NPPs.

Assessing the impact of urbanization on net primary productivity using multi-scale remote sensing data: a case study of Xuzhou, China

NASA Astrophysics Data System (ADS)

Tan, Kun; Zhou, Songyang; Li, Erzhu; Du, Peijun

2015-06-01

An improved Carnegie Ames Stanford Approach (CASA) model based on two kinds of remote sensing (RS) data, Landsat Enhanced Thematic Mapper Plus (ETM +) and Moderate Resolution Imaging Spectro-radiometer (MODIS), and climate variables were applied to estimate the Net Primary Productivity (NPP) of Xuzhou in June of each year from 2001 to 2010. The NPP of the study area decreased as the spatial scale increased. The average NPP of terrestrial vegetation in Xuzhou showed a decreasing trend in recent years, likely due to changes in climate and environment. The study area was divided into four sub-regions, designated as highest, moderately high, moderately low, and lowest in NPP. The area designated as the lowest sub-region in NPP increased with expanding scale, indicating that the NPP distribution varied with different spatial scales. The NPP of different vegetation types was also significantly influenced by scale. In particular, the NPP of urban woodland produced lower estimates because of mixed pixels. Similar trends in NPP were observed with different RS data. In addition, expansion of residential areas and reduction of vegetated areas were the major reasons for NPP change. Land cover changes in urban areas reduced NPP, which could chiefly be attributed to human-induced disturbance.

Impacts of Climate Change/Variability and Human Activities on Contemporary Vegetation Productivity across Africa

NASA Astrophysics Data System (ADS)

Ugbaje, S. U.; Odeh, I. A.; Bishop, T.

2015-12-01

Vegetation productivity is increasingly being impacted upon by climate change/variability and anthropogenic activities, especially in developing countries, where many livelihoods depend on the natural resource base. Despite these impacts, the individual and combined roles of climate and anthropogenic factors on vegetation dynamics have rarely been quantified in many ecosystems and regions of the world. This paper analyzes recent trend in vegetation productivity across Africa and quantified the relative roles of climate change/variability and human activities in driving this trend over 2000-2014 using net primary productivity (NPP) as an indicator. The relative roles of these factors to vegetation productivity change were quantified by comparing the trend slope (p<0.1) and total change in interannual actual NPP (NPPA), potential NPP (NPPP), and human appropriated NPP (NPPH). NPP significantly increased across Africa relative to NPP decline, though the extent of NPP decline is also quite appreciable. Whereas estimated NPP declined by 207 Tg C over 140 X 104 km of land area, vegetation productivity was estimated to improve by 1415 Tg C over 786 X 104 km of land area. NPP improvement is largely concentrated in equatorial and northern hemispheric Africa, while subequatorial Africa exhibited the most NPP decline. Generally, anthropogenic activities dominated climate change/variability in improving or degrading vegetation productivity. Of the estimated total NPP gained over the study period, 32.6, 8.8, and 58.6 % were due to individual human, climate and combined impacts respectively. The contributions of the factors to NPP decline in the same order are: 50.7, 16.0 and 33.3 %. The Central Africa region is where human activities had the greatest impact on NPP improvement; whereas the Sahel and the coastlines of west northern Africa are areas associated with the greatest influence of climate-driven NPP gain. Areas with humans dominating NPP degradation include eastern Angola, western Zambia, and Liberia; whereas climate-driven NPP loss is pronounced in Zambia and Mozambique. Results from this study indicate that, compared to climate change/variability, contemporary anthropogenic activities are contributing more to the decline of Africa's vegetation productivity than to vegetation improvement.

Temporal variability of the NPP-GPP ratio at seasonal and interannual time scales in a temperate beech forest

NASA Astrophysics Data System (ADS)

Campioli, M.; Gielen, B.; Göckede, M.; Papale, D.; Bouriaud, O.; Granier, A.

2011-09-01

The allocation of carbon (C) taken up by the tree canopy for respiration and production of tree organs with different construction and maintenance costs, life span and decomposition rate, crucially affects the residence time of C in forests and their C cycling rate. The carbon-use efficiency, or ratio between net primary production (NPP) and gross primary production (GPP), represents a convenient way to analyse the C allocation at the stand level. In this study, we extend the current knowledge on the NPP-GPP ratio in forests by assessing the temporal variability of the NPP-GPP ratio at interannual (for 8 years) and seasonal (for 1 year) scales for a young temperate beech stand, reporting dynamics for both leaves and woody organs, in particular stems. NPP was determined with biometric methods/litter traps, whereas the GPP was estimated via the eddy covariance micrometeorological technique. The interannual variability of the proportion of C allocated to leaf NPP, wood NPP and leaf plus wood NPP (on average 11% yr-1, 29% yr-1 and 39% yr-1, respectively) was significant among years with up to 12% yr-1 variation in NPP-GPP ratio. Studies focusing on the comparison of NPP-GPP ratio among forests and models using fixed allocation schemes should take into account the possibility of such relevant interannual variability. Multiple linear regressions indicated that the NPP-GPP ratio of leaves and wood significantly correlated with environmental conditions. Previous year drought and air temperature explained about half of the NPP-GPP variability of leaves and wood, respectively, whereas the NPP-GPP ratio was not decreased by severe drought, with large NPP-GPP ratio on 2003 due mainly to low GPP. During the period between early May and mid June, the majority of GPP was allocated to leaf and stem NPP, whereas these sinks were of little importance later on. Improved estimation of seasonal GPP and of the contribution of previous-year reserves to stem growth, as well as reduction of data uncertainty, will be of relevance to increase the accuracy of the seasonal assessment of the NPP-GPP ratio in forests.

Effects of climate warming on net primary productivity in China during 1961-2010.

PubMed

Gu, Fengxue; Zhang, Yuandong; Huang, Mei; Tao, Bo; Guo, Rui; Yan, Changrong

2017-09-01

The response of ecosystems to different magnitudes of climate warming and corresponding precipitation changes during the last few decades may provide an important reference for predicting the magnitude and trajectory of net primary productivity (NPP) in the future. In this study, a process-based ecosystem model, Carbon Exchange between Vegetation, Soil and Atmosphere (CEVSA), was used to investigate the response of NPP to warming at both national and subregional scales during 1961-2010. The results suggest that a 1.3°C increase in temperature stimulated the positive changing trend in NPP at national scale during the past 50 years. Regardless of the magnitude of temperature increase, warming enhanced the increase in NPP; however, the positive trend of NPP decreased when warming exceeded 2°C. The largest increase in NPP was found in regions where temperature increased by 1-2°C, and this rate of increase also contributed the most to the total increase in NPP in China's terrestrial ecosystems. Decreasing precipitation depressed the positive trend in NPP that was stimulated by warming. In northern China, warming depressed the increasing trend of NPP and warming that was accompanied by decreasing precipitation led to negative changing trends in NPP in large parts of northern China, especially when warming exceeded 2°C. However, warming stimulated the increase in NPP until warming was greater than 2°C, and decreased precipitation helped to increase the NPP in southern China.

Spatial and seasonal characterization of net primary productivity and climate variables in southeastern China using MODIS data*

PubMed Central

Peng, Dai-liang; Huang, Jing-feng; Huete, Alfredo R.; Yang, Tai-ming; Gao, Ping; Chen, Yan-chun; Chen, Hui; Li, Jun; Liu, Zhan-yu

2010-01-01

We developed a sophisticated method to depict the spatial and seasonal characterization of net primary productivity (NPP) and climate variables. The role of climate variability in the seasonal variation of NPP exerts delayed and continuous effects. This study expands on this by mapping the seasonal characterization of NPP and climate variables from space using geographic information system (GIS) technology at the pixel level. Our approach was developed in southeastern China using moderate-resolution imaging spectroradiometer (MODIS) data. The results showed that air temperature, precipitation and sunshine percentage contributed significantly to seasonal variation of NPP. In the northern portion of the study area, a significant positive 32-d lagged correlation was observed between seasonal variation of NPP and climate (P<0.01), and the influences of changing climate on NPP lasted for 48 d or 64 d. In central southeastern China, NPP showed 16-d, 48-d, and 96-d lagged correlation with air temperature, precipitation, and sunshine percentage, respectively (P<0.01); the influences of air temperature and precipitation on NPP lasted for 48 d or 64 d, while sunshine influence on NPP only persisted for 16 d. Due to complex topography and vegetation distribution in the southern part of the study region, the spatial patterns of vegetation-climate relationship became complicated and diversiform, especially for precipitation influences on NPP. In the northern part of the study area, all vegetation NPP had an almost similar response to seasonal variation of air temperature except for broad crops. The impacts of seasonal variation of precipitation and sunshine on broad and cereal crop NPP were slightly different from other vegetation NPP. PMID:20349524

Decreases in net primary production and net ecosystem production along a repeated-fires induced forest/grassland gradient

NASA Astrophysics Data System (ADS)

Cheng, C. H.; Huang, Y. H.; Chung-Yu, L.; Menyailo, O.

2016-12-01

Fire is one of the most important disturbances in ecosystems. Fire rapidly releases stored carbon into atmosphere and also plays critical roles on soil properties, light and moisture regimes, and plant structures and communities. With the interventions of climate change and human activities, fire regimes become more severe and frequent. In many parts of world, forest fire regimes can be further altered by grass invasion because the invasive grasses create a positive feedback cycle through their rapid recovery after fires and their high flammability during dry periods and allow forests to be burned repeatedly in a relatively short time. For such invasive grass-fire cycle, a great change of native vegetation community can occur. In this study, we examined a C4 invasive grass () fire-induced forest/grassland gradient to quantify the changes of net primary production (NPP) and net ecosystem production (NEP) from an unburned forest to repeated fire grassland. Our results demonstrated negative effects of repeated fires on NPP and NEP. Within 4 years of the onset of repeated fires on the unburned forest, NPP declined by 14%, mainly due to the reduction in aboveground NPP but offset by increase of belowground NPP. Subsequent fires cumulatively caused reductions in both aboveground and belowground NPP. A total of 40% reduction in the long-term repeated fire induced grassland was found. Soil respiration rate were not significantly different along the forest/grassland gradient. Thus, a great reduction in NEP were shown in grassland, which shifted from 4.6 Mg C ha-1 yr-1 in unburnt forest to -2.6 Mg C ha-1 yr-1. Such great losses are critical within the context of forest carbon cycling and long-term sustainability. Forest management practices that can effectively reduce the likelihood of repeated fires and consequent likelihood of establishment of the grass fire cycle are essential for protecting the forest.

The potential effects of climate change on the distribution and productivity of Cunninghamia lanceolata in China.

PubMed

Liu, Yupeng; Yu, Deyong; Xun, Bin; Sun, Yun; Hao, Ruifang

2014-01-01

Climate changes may have immediate implications for forest productivity and may produce dramatic shifts in tree species distributions in the future. Quantifying these implications is significant for both scientists and managers. Cunninghamia lanceolata is an important coniferous timber species due to its fast growth and wide distribution in China. This paper proposes a methodology aiming at enhancing the distribution and productivity of C. lanceolata against a background of climate change. First, we simulated the potential distributions and establishment probabilities of C. lanceolata based on a species distribution model. Second, a process-based model, the PnET-II model, was calibrated and its parameterization of water balance improved. Finally, the improved PnET-II model was used to simulate the net primary productivity (NPP) of C. lanceolata. The simulated NPP and potential distribution were combined to produce an integrated indicator, the estimated total NPP, which serves to comprehensively characterize the productivity of the forest under climate change. The results of the analysis showed that (1) the distribution of C. lanceolata will increase in central China, but the mean probability of establishment will decrease in the 2050s; (2) the PnET-II model was improved, calibrated, and successfully validated for the simulation of the NPP of C. lanceolata in China; and (3) all scenarios predicted a reduction in total NPP in the 2050s, with a markedly lower reduction under the a2 scenario than under the b2 scenario. The changes in NPP suggested that forest productivity will show a large decrease in southern China and a mild increase in central China. All of these findings could improve our understanding of the impact of climate change on forest ecosystem structure and function and could provide a basis for policy-makers to apply adaptive measures and overcome the unfavorable influences of climate change.

Agricultural conversion reduces biospheric vegetation productivity in the absence of external inputs

NASA Astrophysics Data System (ADS)

Smith, W. K.; Cleveland, C. C.; Reed, S.; Running, S. W.

2013-12-01

Increasing global population, energy demand, and standard of living has driven humanity to co-opt a growing share of the planet's natural resources resulting in many well-known environmental trade-offs. Here, we explored the impact of global-scale agricultural production on a basic resource fundamental to life on Earth: global terrestrial vegetation growth (net primary production; NPP). First, we compared current rates of agricultural NPP - derived from crop-specific agricultural statistics - with rates of natural NPP - derived from satellite measurements. Next, we disaggregated our results by climate zone, conversion type, crop type, management intensity, and region to identify where agricultural conversion has driven significant degradation of biospheric NPP. At the global-scale, our data indicate that agricultural conversion has resulted in a ~7% reduction in biospheric NPP (ΔNPP), although the impact varied widely at the pixel level. Positive ΔNPP values, signifying an increase in NPP due to agricultural conversion, occurred only in areas receiving significant external water and nutrient inputs (i.e., intensively managed areas). Conversely, negative ΔNPP values, signifying a reduction in NPP due to agricultural conversion, occurred over ~90% of agricultural lands globally, with the largest reductions in areas formerly occupied by tropical forests and savannas (71% and 66% reductions in NPP, respectively). Without new global-scale policies that explicitly consider changes in NPP due to land cover conversion, future demand-driven increases in agricultural output - likely dependent on some level of expansion into natural ecosystems - could continue to drive net declines in biospheric NPP, with potential detrimental consequences for global carbon storage. A spatially explicit estimate of the effect of agricultural land cover conversion on natural primary production for 20 staple crops. ΔNPP was estimated independently for a) irrigated, b) high input, c) low input, and d) subsistence management intensities. All remaining vegetated land is represented in grey, while barren land is represented in white. Globally, agricultural land cover conversion has reduced natural primary production by 3.0 × 0.68 Pg C y-1 (i.e., a ~7% reduction in biospheric NPP), with a disproportionately large percentage of this reduction attributable to the conversion of temperate (~44%) and tropical (~50%) ecosystems.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vinnikov, B.; NRC Kurchatov Inst.

According to Scientific and Technical Cooperation between the USA and Russia in the field of nuclear engineering the Idaho National Laboratory has transferred to the possession of the National Research Center ' Kurchatov Inst. ' the SAPHIRE software without any fee. With the help of the software Kurchatov Inst. developed a Pilot Living PSA- Model of Leningrad NPP Unit 1. Computations of core damage frequencies were carried out for additional Initiating Events. In the submitted paper such additional Initiating Events are fires in various compartments of the NPP. During the computations of each fire, structure of the PSA - Modelmore » was not changed, but Fault Trees for the appropriate systems, which are removed from service during the fire, were changed. It follows from the computations, that for ten fires Core Damaged Frequencies (CDF) are not changed. Other six fires will cause additional core damage. On the basis of the calculated results it is possible to determine a degree of importance of these fires and to establish sequence of performance of fire-prevention measures in various places of the NPP. (authors)« less

Determining the contributions of urbanisation and climate change to NPP variations over the last decade in the Yangtze River Delta, China.

PubMed

Wu, Shaohua; Zhou, Shenglu; Chen, Dongxiang; Wei, Zongqiang; Dai, Liang; Li, Xingong

2014-02-15

Terrestrial net primary production (NPP) is an important measure of global change, and identifying the relative contributions of urbanisation and climate change to NPP is important for understanding the impact of human and natural influences on terrestrial systems and the carbon cycle. The objective of this study was to reveal how urbanisation and climate drive changes in NPP. Satellite-based estimates of NPP collected over a 12-year period (1999-2010) were analysed to identify NPP variations in the Yangtze River Delta. Temporal and spatial analysis methods were used to identify the relationships among NPP, nighttime light urbanisation index values, and climatic factors from pixel to regional scales. The NPP of the entire Yangtze River Delta decreased slightly at a rate of -0.5 g C m(-2)a(-1) from 1999 to 2010, but this change was not significant. However, in the urban region, NPP decreased significantly (p<0.05) at a rate of -4.7 g C m(-2)a(-1) due to urbanisation processes. A spatially explicit method was proposed to partition the relative contributions of urbanisation and climate change to NPP variation. The results revealed that the urbanisation factor is the main driving force for NPP change in high-speed urbanisation areas, and the factor accounted for 47% of the variations. However, in the forest and farm regions, the NPP variation was mainly controlled by climate change and residual factors. Copyright © 2013 Elsevier B.V. All rights reserved.

Stabilization of different types of transition states in a single enzyme active site: QM/MM analysis of enzymes in the alkaline phosphatase superfamily.

PubMed

Hou, Guanhua; Cui, Qiang

2013-07-17

The first step for the hydrolysis of a phosphate monoester (pNPP(2-)) in enzymes of the alkaline phosphatase (AP) superfamily, R166S AP and wild-type NPP, is studied using QM/MM simulations based on an approximate density functional theory (SCC-DFTBPR) and a recently introduced QM/MM interaction Hamiltonian. The calculations suggest that similar loose transition states are involved in both enzymes, despite the fact that phosphate monoesters are the cognate substrates for AP but promiscuous substrates for NPP. The computed loose transition states are clearly different from the more synchronous ones previously calculated for diester reactions in the same AP enzymes. Therefore, our results explicitly support the proposal that AP enzymes are able to recognize and stabilize different types of transition states in a single active site. Analysis of the structural features of computed transition states indicates that the plastic nature of the bimetallic site plays a minor role in accommodating multiple types of transition states and that the high degree of solvent accessibility of the AP active site also contributes to its ability to stabilize diverse transition-state structures without the need of causing large structural distortions of the bimetallic motif. The binding mode of the leaving group in the transition state highlights that vanadate may not always be an ideal transition state analog for loose phosphoryl transfer transition states.

Importance of vegetation dynamics for future terrestrial carbon cycling

NASA Astrophysics Data System (ADS)

Ahlström, Anders; Xia, Jianyang; Arneth, Almut; Luo, Yiqi; Smith, Benjamin

2015-05-01

Terrestrial ecosystems currently sequester about one third of anthropogenic CO2 emissions each year, an important ecosystem service that dampens climate change. The future fate of this net uptake of CO2 by land based ecosystems is highly uncertain. Most ecosystem models used to predict the future terrestrial carbon cycle share a common architecture, whereby carbon that enters the system as net primary production (NPP) is distributed to plant compartments, transferred to litter and soil through vegetation turnover and then re-emitted to the atmosphere in conjunction with soil decomposition. However, while all models represent the processes of NPP and soil decomposition, they vary greatly in their representations of vegetation turnover and the associated processes governing mortality, disturbance and biome shifts. Here we used a detailed second generation dynamic global vegetation model with advanced representation of vegetation growth and mortality, and the associated turnover. We apply an emulator that describes the carbon flows and pools exactly as in simulations with the full model. The emulator simulates ecosystem dynamics in response to 13 different climate or Earth system model simulations from the Coupled Model Intercomparison Project Phase 5 ensemble under RCP8.5 radiative forcing. By exchanging carbon cycle processes between these 13 simulations we quantified the relative roles of three main driving processes of the carbon cycle; (I) NPP, (II) vegetation dynamics and turnover and (III) soil decomposition, in terms of their contribution to future carbon (C) uptake uncertainties among the ensemble of climate change scenarios. We found that NPP, vegetation turnover (including structural shifts, wild fires and mortality) and soil decomposition rates explained 49%, 17% and 33%, respectively, of uncertainties in modelled global C-uptake. Uncertainty due to vegetation turnover was further partitioned into stand-clearing disturbances (16%), wild fires (0%), stand dynamics (7%), reproduction (10%) and biome shifts (67%) globally. We conclude that while NPP and soil decomposition rates jointly account for 83% of future climate induced C-uptake uncertainties, vegetation turnover and structure, dominated by biome shifts, represent a significant fraction globally and regionally (tropical forests: 40%), strongly motivating their representation and analysis in future C-cycle studies.

Water availability limits tree productivity, carbon stocks, and carbon residence time in mature forests across the western US

NASA Astrophysics Data System (ADS)

Berner, Logan T.; Law, Beverly E.; Hudiburg, Tara W.

2017-01-01

Water availability constrains the structure and function of terrestrial ecosystems and is projected to change in many parts of the world over the coming century. We quantified the response of tree net primary productivity (NPP), live biomass (BIO), and mean carbon residence time (CRT = BIO / NPP) to spatial variation in water availability in the western US. We used forest inventory measurements from 1953 mature stands (> 100 years) in Washington, Oregon, and California (WAORCA) along with satellite and climate data sets covering the western US. We summarized forest structure and function in both domains along a 400 cm yr-1 hydrologic gradient, quantified with a climate moisture index (CMI) based on the difference between precipitation and reference evapotranspiration summed over the water year (October-September) and then averaged annually from 1985 to 2014 (CMIwy). Median NPP, BIO, and CRT computed at 10 cm yr-1 intervals along the CMIwy gradient increased monotonically with increasing CMIwy across both WAORCA (rs = 0.93-0.96, p < 0.001) and the western US (rs = 0.93-0.99, p < 0.001). Field measurements from WAORCA showed that median NPP increased from 2.2 to 5.6 Mg C ha-1 yr-1 between the driest and wettest 5 % of sites, while BIO increased from 26 to 281 Mg C ha-1 and CRT increased from 11 to 49 years. The satellite data sets revealed similar changes over the western US, though these data sets tended to plateau in the wettest areas, suggesting that additional efforts are needed to better quantify NPP and BIO from satellites in high-productivity, high-biomass forests. Our results illustrate that long-term average water availability is a key environmental constraint on tree productivity, carbon storage, and carbon residence time in mature forests across the western US, underscoring the need to assess potential ecosystem response to projected warming and drying over the coming century.

Information systems - Issues in global habitability

NASA Technical Reports Server (NTRS)

Norman, S. D.; Brass, J. A.; Jones, H.; Morse, D. R.

1984-01-01

The present investigation is concerned with fundamental issues, related to information considerations, which arise in an interdisciplinary approach to questions of global habitability. Information system problems and issues are illustrated with the aid of an example involving biochemical cycling and biochemical productivity. The estimation of net primary production (NPP) as an important consideration in the overall global habitability issue is discussed. The NPP model requires three types of data, related to meteorological information, a land surface inventory, and the vegetation structure. Approaches for obtaining and processing these data are discussed. Attention is given to user requirements, information system requirements, workstations, network communications, hardware/software access, and data management.

Comparing cropland net primary production estimates from inventory, a satellite-based model, and a process-based model in the Midwest of the United States

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Zhengpeng; Liu, Shuguang; Tan, Zhengxi

2014-04-01

Accurately quantifying the spatial and temporal variability of net primary production (NPP) for croplands is essential to understand regional cropland carbon dynamics. We compared three NPP estimates for croplands in the Midwestern United States: inventory-based estimates using crop yield data from the U.S. Department of Agriculture (USDA) National Agricultural Statistics Service (NASS); estimates from the satellite-based Moderate Resolution Imaging Spectroradiometer (MODIS) NPP product; and estimates from the General Ensemble biogeochemical Modeling System (GEMS) process-based model. The three methods estimated mean NPP in the range of 469–687 g C m -2 yr -1 and total NPP in the range of 318–490more » Tg C yr -1 for croplands in the Midwest in 2007 and 2008. The NPP estimates from crop yield data and the GEMS model showed the mean NPP for croplands was over 650 g C m -2 yr -1 while the MODIS NPP product estimated the mean NPP was less than 500 g C m -2 yr -1. MODIS NPP also showed very different spatial variability of the cropland NPP from the other two methods. We found these differences were mainly caused by the difference in the land cover data and the crop specific information used in the methods. Our study demonstrated that the detailed mapping of the temporal and spatial change of crop species is critical for estimating the spatial and temporal variability of cropland NPP. Finally, we suggest that high resolution land cover data with species–specific crop information should be used in satellite-based and process-based models to improve carbon estimates for croplands.« less

Comparing cropland net primary production estimates from inventory, a satellite-based model, and a process-based model in the Midwest of the United States

USGS Publications Warehouse

Li, Zhengpeng; Liu, Shuguang; Tan, Zhengxi; Bliss, Norman B.; Young, Claudia J.; West, Tristram O.; Ogle, Stephen M.

2014-01-01

Accurately quantifying the spatial and temporal variability of net primary production (NPP) for croplands is essential to understand regional cropland carbon dynamics. We compared three NPP estimates for croplands in the Midwestern United States: inventory-based estimates using crop yield data from the U.S. Department of Agriculture (USDA) National Agricultural Statistics Service (NASS); estimates from the satellite-based Moderate Resolution Imaging Spectroradiometer (MODIS) NPP product; and estimates from the General Ensemble biogeochemical Modeling System (GEMS) process-based model. The three methods estimated mean NPP in the range of 469–687 g C m−2 yr−1and total NPP in the range of 318–490 Tg C yr−1 for croplands in the Midwest in 2007 and 2008. The NPP estimates from crop yield data and the GEMS model showed the mean NPP for croplands was over 650 g C m−2 yr−1 while the MODIS NPP product estimated the mean NPP was less than 500 g C m−2 yr−1. MODIS NPP also showed very different spatial variability of the cropland NPP from the other two methods. We found these differences were mainly caused by the difference in the land cover data and the crop specific information used in the methods. Our study demonstrated that the detailed mapping of the temporal and spatial change of crop species is critical for estimating the spatial and temporal variability of cropland NPP. We suggest that high resolution land cover data with species–specific crop information should be used in satellite-based and process-based models to improve carbon estimates for croplands.

Materials Data on NpP (SG:225) by Materials Project

DOE Data Explorer

Kristin Persson

2015-02-09

Computed materials data using density functional theory calculations. These calculations determine the electronic structure of bulk materials by solving approximations to the Schrodinger equation. For more information, see https://materialsproject.org/docs/calculations

Assessing the impact of the urbanization process on net primary productivity in China in 1989-2000.

PubMed

Tian, Guangjin; Qiao, Zhi

2014-01-01

Urban development affects the material circulation and energy flow of ecosystems, thereby affecting the Net Primary Productivity (NPP). The loss of NPP due to urban expansion was calculated integrating GLO-PEM with remote sensing and GIS techniques in China during the period of 1989-2000. Using urban expansion and the mean NPP for the different land use types in the fourteen regions, the total loss of NPP was calculated as 0.95 Tg C, which accounted for 0.03% of the national NPP of 1989. The total loss of NPP due to the transformation from cropland to urban land accounted for 91.93%, followed by forest (7.17%) and grassland (0.69%). However, the conversion from unused land, industrial and construction land, and water bodies to urban land resulted in an increase in the NPP. The regions locating in eastern China and middle China had large reductions in the total NPP due to urban expansion. Copyright © 2013 Elsevier Ltd. All rights reserved.

Psychophysiological characteristics in the ChNPP accident clean-up workers, exclusion zone evacuees and anti-terrorist operation servicemen.

PubMed

Loganovsky, K M; Gresko, M V

2017-12-01

Evaluation of interdependencies between psychometric parameters and spontaneous cerebral electric activity in the ChNPP accident clean up workers, evacuees from exclusion zone, and anti terrorist operation service men. Psychometric and neurophysiological parameters were reviewed in the study subjects retro spectively and in comparison. Study population included the ChNPP accident clean up workers (ACUW), evacuees from the 30 kilometer exclusion zone, specifically in a sample from a cohort of the NRCRM Clinical Epidemiological Register (n=316), and anti terrorist operation servicemen (n=81) undergoing rehabilitation in the NRCRM Radiation psychoneurology department. A control group of persons (n=84) was also involved in the study. Diagnostic method ology for the characteristic personality features, namely the personality test of character accentuation by G. Shmishek and K. Leonhard, and Eysenck Personality Inventory (by H. J. Eysenck) were applied. Computer EEGs were registered and analyzed on the 16 channel electroencephalograph DX 4000 (Kharkiv, Ukraine). In the aftermath of the emergency period, a personality deformation occurs in the clean up workers and survivors of the ChNPP accident, which is characterized by aggravation of such personality traits as jam (fixedness), emotiveness, pedantry, anxiety, cyclothymia, excitability and disthymia, with diminished hyperthymia and ostenta tion (demonstrability). Increased incidence of fixedness, pedantry, cyclothymia, affectability and disthymia with decreased hyperthymia were revealed in the group of ATO participants. Cerebral bioelectrical activity in the ChNPP ACUW was characterized by an increased delta activity power with decreased beta and theta activity power and dom inant frequency in comparison with all groups of survivors and control group. The ATO group was different from groups of survivors and control group with a lower power of delta, theta and beta activity, and a higher dominant frequency. Introversion featured a negative correlation with delta and theta activity index along with positive cor relation with alpha activity index. The absolute spectral power of beta, alpha and theta bands positively correlated with introversion. Increase in neuroticism featured a decrease in theta activity index and an increase in beta activ ity index along with decreased theta and delta band absolute spectral power. There is a deformation of personality in the group of ChNPP ACUW, evacuees from the 30 kilometer zone and ATO servicemen. Deformation of personality correlates with abnormal cerebral bioelectrical activity. K.M. Loganovsky, M.V. Gresko.

Assessing the Spatiotemporal Variation and Impact Factors of Net Primary Productivity in China

NASA Astrophysics Data System (ADS)

Wang, Xue; Tan, Kun; Chen, Baozhang; Du, Peijun

2017-03-01

In this study, the net primary productivity (NPP) in China from 2001 to 2012 was estimated based on the Carnegie-Ames-Stanford Approach (CASA) model using Moderate Resolution Imaging Spectroradiometer (MODIS) and meteorological datasets, and the accuracy was verified by a ChinaFLUX dataset. It was found that the spatiotemporal variations in NPP present a downward trend with the increase of latitude and longitude. Moreover, the influence of climate change on the evolution of NPP shows that NPP has had different impact factors in different regions and periods over the 12 years. The eastern region has shown the largest increase in gross regional product (GRP) and a significant fluctuation in NPP over the 12 years. Meanwhile, NPP in the eastern and central regions is significantly positively correlated with annual solar radiation, while NPP in these two regions is significantly negatively correlated with the growth rate of GRP. It is concluded that both the development of the economy and climate change have influenced NPP evolution in China. In addition, NPP has shown a steadily rising trend over the 12 years as a result of the great importance attributed to ecological issues when developing the economy.

Nutritional geometry of calcium and phosphorus nutrition in broiler chicks. Growth performance, skeletal health and intake arrays.

PubMed

Bradbury, E J; Wilkinson, S J; Cronin, G M; Thomson, P C; Bedford, M R; Cowieson, A J

2014-07-01

The interaction between calcium (Ca) and non-phytate phosphorus (nPP) in broiler nutrition and skeletal health is highly complex with many factors influencing their digestion, absorption and utilisation. The use of an investigative model such as the geometric framework allows a graphical approach to explore these complex interactions. A total of 600 Ross 308-day-old male broiler chicks were allocated to one of 15 dietary treatments with five replicates and eight birds per replicate. Dietary treatments were formulated to one of three total densities of total Ca+nPP; high (15 g/kg), medium (13.5 g/kg) and low (12 g/kg) and at each density there were five different ratios of Ca : nPP (4, 2.75, 2.1, 1.5 and 1.14 : 1). Weekly performance data was collected and at the end of the experiment birds were individually weighed and the right leg removed for tibia ash analysis. Skeletal health was assessed using the latency to lie (LTL) at day 27. At low Ca and high nPP as well as high Ca and low nPP diets, birds had reduced feed intake, BW gain, poorer feed efficiency and lower tibia ash, resulting in a significant interaction between dietary Ca and nPP (P<0.05). LTL times were negatively influenced by diets having either a broad ratio (high Ca, low nPP) or too narrow a ratio (low Ca, high nPP) indicating that shorter LTL times may be influenced by the ratio of Ca : nPP rather than absolute concentrations of either mineral. The calculated intake arrays show that broilers more closely regulate Ca intake than nPP intake. Broilers are willing to over consume nPP to defend a Ca intake target more so than they are willing to over consume Ca to defend an nPP target. Overall dietary nPP was more influential on performance metrics, however, from the data it may appear that birds prioritise Ca intake over nPP and broadly ate to meet this requirement. As broilers are more willing to eat to a Ca intake target rather than an nPP intake target, this emphasises the importance of formulating diets to a accurately balanced density of Ca : nPP considering the biological importance of both minerals.

[Variation trends of natural vegetation net primary productivity in China under climate change scenario].

PubMed

Zhao, Dong-sheng; Wu, Shao-hong; Yin, Yun-he

2011-04-01

Based on the widely used Lund-Potsdam-Jena Dynamic Global Vegetation Model (LPJ) for climate change study, and according to the features of natural environment in China, the operation mechanism of the model was adjusted, and the parameters were modified. With the modified LPJ model and taking 1961-1990 as baseline period, the responses of natural vegetation net primary productivity (NPP) in China to climate change in 1991-2080 were simulated under the Special Report on Emissions Scenarios (SRES) B2 scenario. In 1961-1990, the total NPP of natural vegetation in China was about 3.06 Pg C a(-1); in 1961-2080, the total NPP showed a fluctuant decreasing trend, with an accelerated decreasing rate. Under the condition of slight precipitation change, the increase of mean air temperature would have definite adverse impact on the NPP. Spatially, the NPP decreased from southeast coast to northwest inland, and this pattern would have less variation under climate change. In eastern China with higher NPP, especially in Northeast China, east of North China, and Loess Plateau, the NPP would mainly have a decreasing trend; while in western China with lower NPP, especially in the Tibetan Plateau and Tarim Basin, the NPP would be increased. With the intensive climate change, such a variation trend of NPP would be more obvious.

Impacts of sea ice retreat, thinning, and melt-pond proliferation on the summer phytoplankton bloom in the Chukchi Sea, Arctic Ocean

NASA Astrophysics Data System (ADS)

Palmer, Molly A.; Saenz, Benjamin T.; Arrigo, Kevin R.

2014-07-01

In 2011, a massive phytoplankton bloom was observed in the Chukchi Sea under first-year sea ice (FYI), an environment in which primary productivity (PP) has historically been low. In this paper, we use a 1-D biological model of the Chukchi shelf ecosystem, in conjunction with in situ chemical and physiological data, to better understand the conditions that facilitated the development of such an unprecedented bloom. In addition, to assess the effects of changing Arctic environmental conditions on net PP (NPP), we perform model runs with varying sea ice and snow thickness, timing of melt, melt ponds, and biological parameters. Results from model runs with conditions similar to 2011 indicate that first-year ice (FYI) with at least 10% melt pond coverage transmits sufficient light to support the growth of shade-adapted Arctic phytoplankton. Increasing pond fraction by 20% enhanced peak under-ice NPP by 26% and produced rates more comparable to those measured during the 2011 bloom, but there was no effect of further increasing pond fraction. One of the important consequences of large under-ice blooms is that they consume a substantial fraction of surface nutrients such that NPP is greatly diminished in the marginal ice zone (MIZ) following ice retreat, where NPP has historically been the highest. In contrast, in model runs with <10% ponds, no under-ice bloom formed, and although peak MIZ NPP increased by 18-30%, this did not result in higher total annual NPP. This suggests that under-ice blooms contribute importantly to total annual NPP. Indeed, in all runs exhibiting under-ice blooms, total annual NPP was higher than in runs with the majority of NPP based in open water. Consistent with this, in model runs where ice melted one month earlier, peak under-ice NPP decreased 30%, and annual NPP was lower as well. The only exception was the case with no sea ice in the region: a weak bloom in early May was followed by low but sustained NPP throughout the entire growth season (almost all of which occurred in deep, subsurface layers), resulting in higher total annual NPP than in cases with sea ice present. Our results also show that both ultraviolet radiation and zooplankton grazers reduce peak open water NPP but have little impact on under-ice NPP, which has important implications for the relative proportion of NPP concentrated in pelagic vs. benthic food webs. Finally, the shift in the relative amount of NPP occurring in under-ice vs. open-water environments may affect total ecosystem productivity.

Ecosystem Reversals of Fortune in Response to Long-Term Experimental N Deposition.

NASA Astrophysics Data System (ADS)

Vourlitis, G. L.

2017-12-01

Anthropogenic nitrogen (N) deposition has the capacity to alter terrestrial ecosystem structure and function; however, short-term (months-years) responses may be fundamentally different than long-term (years-decades) responses. Here the results of a 14 year field N addition experiment are reported for two different Southern Californian semi-arid shrublands, a post-fire chaparral and a mature coastal sage scrub (CSS), that have been exposed to 50 kgN ha-1 yr-1 since 2003. Since >90% of the anthropogenic N in this region consists of dry deposition, N was added during the late-summer or early-fall each year to assess how dry N inputs alter ecosystem processes. Both shrublands experienced complete reversals in their response to experimental N input. For example, post-fire chaparral plots exposed to added N had significantly lower net primary production (NPP) than control plots over the first 3 years of the experiment, but thereafter, the NPP in N plots increased consistently each year and became significantly higher than in control plots after 7 years of N fertilization. In CSS, NPP and the abundance of Artemisia californica, a co-dominant shrub, increased significantly in N plots over the first 6 years, but thereafter, NPP and the abundance of A. californica and Salvia mellifera, the other co-dominant shrub, declined. Now the N plots have a lower NPP and are dominated by the invasive annual Brassica nigra. These transient responses, and interactions between N accumulation and other factors such as post-fire succession (chaparral) and chronic drought (CSS), would have been missed if the experiment was ended after the end of a typical funding cycle, and highlighting the importance of long-duration field experiments in assessing ecosystem responses to chronic N enrichment.

Global and regional ecosystem modeling: comparison of model outputs and field measurements

NASA Astrophysics Data System (ADS)

Olson, R. J.; Hibbard, K.

2003-04-01

The Ecosystem Model-Data Intercomparison (EMDI) Workshops provide a venue for global ecosystem modeling groups to compare model outputs against measurements of net primary productivity (NPP). The objective of EMDI Workshops is to evaluate model performance relative to observations in order to improve confidence in global model projections terrestrial carbon cycling. The questions addressed by EMDI include: How does the simulated NPP compare with the field data across biome and environmental gradients? How sensitive are models to site-specific climate? Does additional mechanistic detail in models result in a better match with field measurements? How useful are the measures of NPP for evaluating model predictions? How well do models represent regional patterns of NPP? Initial EMDI results showed general agreement between model predictions and field measurements but with obvious differences that indicated areas for potential data and model improvement. The effort was built on the development and compilation of complete and consistent databases for model initialization and comparison. Database development improves the data as well as models; however, there is a need to incorporate additional observations and model outputs (LAI, hydrology, etc.) for comprehensive analyses of biogeochemical processes and their relationships to ecosystem structure and function. EMDI initialization and NPP data sets are available from the Oak Ridge National Laboratory Distributed Active Archive Center http://www.daac.ornl.gov/. Acknowledgements: This work was partially supported by the International Geosphere-Biosphere Programme - Data and Information System (IGBP-DIS); the IGBP-Global Analysis, Interpretation and Modelling Task Force (GAIM); the National Center for Ecological Analysis and Synthesis (NCEAS); and the National Aeronautics and Space Administration (NASA) Terrestrial Ecosystem Program. Oak Ridge National Laboratory is managed by UT-Battelle LLC for the U.S. Department of Energy under contract DE-AC05-00OR22725

KSC-2011-7546

NASA Image and Video Library

2011-10-26

VANDENBERG AIR FORCE BASE, Calif. -- Andrew Carson, NPP program executive, NASA Headquarters, Washington, DC, participates in the prelaunch news conference at Vandenberg Air Force Base, Calif., for NASA’s National Polar-orbiting Operational Environmental Satellite System Preparatory Project (NPP) spacecraft. NPP represents a critical first step in building the next-generation of Earth-observing satellites. NPP will carry the first of the new sensors developed for this satellite fleet, now known as the Joint Polar Satellite System (JPSS), to be launched in 2016. NPP is the bridge between NASA's Earth Observing System (EOS) satellites and the forthcoming series of JPSS satellites. The mission will test key technologies and instruments for the JPSS missions. NPP is targeted to launch Oct. 28 from Space Launch Complex-2 aboard a United Launch Alliance Delta II rocket. For more information, visit http://www.nasa.gov/NPP. Photo credit: NASA/VAFB

KSC-2011-7547

NASA Image and Video Library

2011-10-26

VANDENBERG AIR FORCE BASE, Calif. -- Ken Schwer, NPP project manager, Goddard Space Flight Center, Greenbelt, Md., participates in the prelaunch news conference at Vandenberg Air Force Base, Calif., for NASA’s National Polar-orbiting Operational Environmental Satellite System Preparatory Project (NPP) spacecraft. NPP represents a critical first step in building the next-generation of Earth-observing satellites. NPP will carry the first of the new sensors developed for this satellite fleet, now known as the Joint Polar Satellite System (JPSS), to be launched in 2016. NPP is the bridge between NASA's Earth Observing System (EOS) satellites and the forthcoming series of JPSS satellites. The mission will test key technologies and instruments for the JPSS missions. NPP is targeted to launch Oct. 28 from Space Launch Complex-2 aboard a United Launch Alliance Delta II rocket. For more information, visit http://www.nasa.gov/NPP. Photo credit: NASA/VAFB

Relative importance of climate changes at different time scales on net primary productivity-a case study of the Karst area of northwest Guangxi, China.

PubMed

Liu, Huiyu; Zhang, Mingyang; Lin, Zhenshan

2017-10-05

Climate changes are considered to significantly impact net primary productivity (NPP). However, there are few studies on how climate changes at multiple time scales impact NPP. With MODIS NPP product and station-based observations of sunshine duration, annual average temperature and annual precipitation, impacts of climate changes at different time scales on annual NPP, have been studied with EEMD (ensemble empirical mode decomposition) method in the Karst area of northwest Guangxi, China, during 2000-2013. Moreover, with partial least squares regression (PLSR) model, the relative importance of climatic variables for annual NPP has been explored. The results show that (1) only at quasi 3-year time scale do sunshine duration and temperature have significantly positive relations with NPP. (2) Annual precipitation has no significant relation to NPP by direct comparison, but significantly positive relation at 5-year time scale, which is because 5-year time scale is not the dominant scale of precipitation; (3) the changes of NPP may be dominated by inter-annual variabilities. (4) Multiple time scales analysis will greatly improve the performance of PLSR model for estimating NPP. The variable importance in projection (VIP) scores of sunshine duration and temperature at quasi 3-year time scale, and precipitation at quasi 5-year time scale are greater than 0.8, indicating important for NPP during 2000-2013. However, sunshine duration and temperature at quasi 3-year time scale are much more important. Our results underscore the importance of multiple time scales analysis for revealing the relations of NPP to changing climate.

NSR&D Program Fiscal Year (FY) 2015 Call for Proposals Mitigation of Seismic Risk at Nuclear Facilities using Seismic Isolation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Coleman, Justin

2015-02-01

Seismic isolation (SI) has the potential to drastically reduce seismic response of structures, systems, or components (SSCs) and therefore the risk associated with large seismic events (large seismic event could be defined as the design basis earthquake (DBE) and/or the beyond design basis earthquake (BDBE) depending on the site location). This would correspond to a potential increase in nuclear safety by minimizing the structural response and thus minimizing the risk of material release during large seismic events that have uncertainty associated with their magnitude and frequency. The national consensus standard America Society of Civil Engineers (ASCE) Standard 4, Seismic Analysismore » of Safety Related Nuclear Structures recently incorporated language and commentary for seismically isolating a large light water reactor or similar large nuclear structure. Some potential benefits of SI are: 1) substantially decoupling the SSC from the earthquake hazard thus decreasing risk of material release during large earthquakes, 2) cost savings for the facility and/or equipment, and 3) applicability to both nuclear (current and next generation) and high hazard non-nuclear facilities. Issue: To date no one has evaluated how the benefit of seismic risk reduction reduces cost to construct a nuclear facility. Objective: Use seismic probabilistic risk assessment (SPRA) to evaluate the reduction in seismic risk and estimate potential cost savings of seismic isolation of a generic nuclear facility. This project would leverage ongoing Idaho National Laboratory (INL) activities that are developing advanced (SPRA) methods using Nonlinear Soil-Structure Interaction (NLSSI) analysis. Technical Approach: The proposed study is intended to obtain an estimate on the reduction in seismic risk and construction cost that might be achieved by seismically isolating a nuclear facility. The nuclear facility is a representative pressurized water reactor building nuclear power plant (NPP) structure. Figure 1: Project activities The study will consider a representative NPP reinforced concrete reactor building and representative plant safety system. This study will leverage existing research and development (R&D) activities at INL. Figure 1 shows the proposed study steps with the steps in blue representing activities already funded at INL and the steps in purple the activities that would be funded under this proposal. The following results will be documented: 1) Comparison of seismic risk for the non-seismically isolated (non-SI) and seismically isolated (SI) NPP, and 2) an estimate of construction cost savings when implementing SI at the site of the generic NPP.« less

Forecasting carbon budget under climate change and CO2 fertilization for subtropical region in China using integrated biosphere simulator (IBIS) model

USGS Publications Warehouse

Zhu, Q.; Jiang, H.; Liu, J.; Peng, C.; Fang, X.; Yu, S.; Zhou, G.; Wei, X.; Ju, W.

2011-01-01

The regional carbon budget of the climatic transition zone may be very sensitive to climate change and increasing atmospheric CO2 concentrations. This study simulated the carbon cycles under these changes using process-based ecosystem models. The Integrated Biosphere Simulator (IBIS), a Dynamic Global Vegetation Model (DGVM), was used to evaluate the impacts of climate change and CO2 fertilization on net primary production (NPP), net ecosystem production (NEP), and the vegetation structure of terrestrial ecosystems in Zhejiang province (area 101,800 km2, mainly covered by subtropical evergreen forest and warm-temperate evergreen broadleaf forest) which is located in the subtropical climate area of China. Two general circulation models (HADCM3 and CGCM3) representing four IPCC climate change scenarios (HC3AA, HC3GG, CGCM-sresa2, and CGCM-sresb1) were used as climate inputs for IBIS. Results show that simulated historical biomass and NPP are consistent with field and other modelled data, which makes the analysis of future carbon budget reliable. The results indicate that NPP over the entire Zhejiang province was about 55 Mt C yr-1 during the last half of the 21st century. An NPP increase of about 24 Mt C by the end of the 21st century was estimated with the combined effects of increasing CO2 and climate change. A slight NPP increase of about 5 Mt C was estimated under the climate change alone scenario. Forests in Zhejiang are currently acting as a carbon sink with an average NEP of about 2.5 Mt C yr-1. NEP will increase to about 5 Mt C yr-1 by the end of the 21st century with the increasing atmospheric CO2 concentration and climate change. However, climate change alone will reduce the forest carbon sequestration of Zhejiang's forests. Future climate warming will substantially change the vegetation cover types; warm-temperate evergreen broadleaf forest will be gradually substituted by subtropical evergreen forest. An increasing CO2 concentration will have little contribution to vegetation changes. Simulated NPP shows geographic patterns consistent with temperature to a certain extent, and precipitation is not the limiting factor for forest NPP in the subtropical climate conditions. There is no close relationship between the spatial pattern of NEP and climate condition.

Forecasting carbon budget under climate change and CO 2 fertilization for subtropical region in China using integrated biosphere simulator (IBIS) model

USGS Publications Warehouse

Zhu, Q.; Jiang, H.; Liu, J.; Peng, C.; Fang, X.; Yu, S.; Zhou, G.; Wei, X.; Ju, W.

2011-01-01

The regional carbon budget of the climatic transition zone may be very sensitive to climate change and increasing atmospheric CO 2 concentrations. This study simulated the carbon cycles under these changes using process-based ecosystem models. The Integrated Biosphere Simulator (IBIS), a Dynamic Global Vegetation Model (DGVM), was used to evaluate the impacts of climate change and CO 2 fertilization on net primary production (NPP), net ecosystem production (NEP), and the vegetation structure of terrestrial ecosystems in Zhejiang province (area 101,800 km 2, mainly covered by subtropical evergreen forest and warm-temperate evergreen broadleaf forest) which is located in the subtropical climate area of China. Two general circulation models (HADCM3 and CGCM3) representing four IPCC climate change scenarios (HC3AA, HC3GG, CGCM-sresa2, and CGCM-sresb1) were used as climate inputs for IBIS. Results show that simulated historical biomass and NPP are consistent with field and other modelled data, which makes the analysis of future carbon budget reliable. The results indicate that NPP over the entire Zhejiang province was about 55 Mt C yr -1 during the last half of the 21 st century. An NPP increase of about 24 Mt C by the end of the 21 st century was estimated with the combined effects of increasing CO 2 and climate change. A slight NPP increase of about 5 Mt C was estimated under the climate change alone scenario. Forests in Zhejiang are currently acting as a carbon sink with an average NEP of about 2.5 Mt C yr -1. NEP will increase to about 5 Mt C yr -1 by the end of the 21 st century with the increasing atmospheric CO 2 concentration and climate change. However, climate change alone will reduce the forest carbon sequestration of Zhejiang's forests. Future climate warming will substantially change the vegetation cover types; warm-temperate evergreen broadleaf forest will be gradually substituted by subtropical evergreen forest. An increasing CO 2 concentration will have little contribution to vegetation changes. Simulated NPP shows geographic patterns consistent with temperature to a certain extent, and precipitation is not the limiting factor for forest NPP in the subtropical climate conditions. There is no close relationship between the spatial pattern of NEP and climate condition.

Experience, use, and performance measurement of the Hadoop File System in a typical nuclear physics analysis workflow

NASA Astrophysics Data System (ADS)

Sangaline, E.; Lauret, J.

2014-06-01

The quantity of information produced in Nuclear and Particle Physics (NPP) experiments necessitates the transmission and storage of data across diverse collections of computing resources. Robust solutions such as XRootD have been used in NPP, but as the usage of cloud resources grows, the difficulties in the dynamic configuration of these systems become a concern. Hadoop File System (HDFS) exists as a possible cloud storage solution with a proven track record in dynamic environments. Though currently not extensively used in NPP, HDFS is an attractive solution offering both elastic storage and rapid deployment. We will present the performance of HDFS in both canonical I/O tests and for a typical data analysis pattern within the RHIC/STAR experimental framework. These tests explore the scaling with different levels of redundancy and numbers of clients. Additionally, the performance of FUSE and NFS interfaces to HDFS were evaluated as a way to allow existing software to function without modification. Unfortunately, the complicated data structures in NPP are non-trivial to integrate with Hadoop and so many of the benefits of the MapReduce paradigm could not be directly realized. Despite this, our results indicate that using HDFS as a distributed filesystem offers reasonable performance and scalability and that it excels in its ease of configuration and deployment in a cloud environment.

Net primary productivity of China's terrestrial ecosystems from a process model driven by remote sensing.

PubMed

Feng, X; Liu, G; Chen, J M; Chen, M; Liu, J; Ju, W M; Sun, R; Zhou, W

2007-11-01

The terrestrial carbon cycle is one of the foci in global climate change research. Simulating net primary productivity (NPP) of terrestrial ecosystems is important for carbon cycle research. In this study, China's terrestrial NPP was simulated using the Boreal Ecosystem Productivity Simulator (BEPS), a carbon-water coupled process model based on remote sensing inputs. For these purposes, a national-wide database (including leaf area index, land cover, meteorology, vegetation and soil) at a 1 km resolution and a validation database were established. Using these databases and BEPS, daily maps of NPP for the entire China's landmass in 2001 were produced, and gross primary productivity (GPP) and autotrophic respiration (RA) were estimated. Using the simulated results, we explore temporal-spatial patterns of China's terrestrial NPP and the mechanisms of its responses to various environmental factors. The total NPP and mean NPP of China's landmass were 2.235 GtC and 235.2 gCm(-2)yr(-1), respectively; the total GPP and mean GPP were 4.418 GtC and 465 gCm(-2)yr(-1); and the total RA and mean RA were 2.227 GtC and 234 gCm(-2)yr(-1), respectively. On average, NPP was 50.6% of GPP. In addition, statistical analysis of NPP of different land cover types was conducted, and spatiotemporal patterns of NPP were investigated. The response of NPP to changes in some key factors such as LAI, precipitation, temperature, solar radiation, VPD and AWC are evaluated and discussed.

Suomi NPP VIIRS spectral characterization: understanding multiple RSR releases

NASA Astrophysics Data System (ADS)

Moeller, Chris; McIntire, Jeff; Schwarting, Tom; Moyer, Dave; Costa, Juliette

2012-09-01

The Suomi National Polar-orbiting Partnership (S-NPP) satellite was successfully launched on October 28, 2011, beginning the on-orbit era of the Visible Infrared Imager Radiometer Suite (VIIRS). In support of atlaunch readiness, VIIRS underwent a rigorous pre-launch test program to characterize its spatial, radiometric, and spectral performance. Spectral measurements, the subject of this paper, were collected during instrument level testing at Raytheon Corp. (summer 2009), and then again in a special spectral test for VisNIR bands during spacecraft level testing at Ball Aerospace and Technologies Corp. (spring 2010). These spectral performance measurements were analyzed by industry (Northrop Grumman, NG) and by the Relative Spectral Response (RSR) subgroup of the Government team, (NASA, Aerospace Corp., MIT/Lincoln Lab, Univ. Wisconsin) leading to releases of the S-NPP VIIRS RSR characterization by both NG and the Government team. The NG RSR analysis was planned to populate the Look-Up-Tables (LUTs) that support the various VIIRS operational products, while the Government team analysis was initially intended as a verification of the NG RSR product as well as an early release RSR characterization for the science community's pre-launch application. While the Government team deemed the NG December 2010 RSR release as acceptable for the "at-launch" RSR characterization during the pre-launch phase, the Government team has now (post-launch checkout phase) recommended for using the NG October 2011 RSR release as an update for the LUTs used in VIIRS SDR and EDR operational processing. Meanwhile the Government team RSR releases remain available to the community for their investigative interests, and may evolve if new understanding of VIIRS spectral performance is revealed in the S-NPP post-launch era.

Estimating crop net primary production using inventory data and MODIS-derived parameters

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bandaru, Varaprasad; West, Tristram O.; Ricciuto, Daniel M.

2013-06-03

National estimates of spatially-resolved cropland net primary production (NPP) are needed for diagnostic and prognostic modeling of carbon sources, sinks, and net carbon flux. Cropland NPP estimates that correspond with existing cropland cover maps are needed to drive biogeochemical models at the local scale and over national and continental extents. Existing satellite-based NPP products tend to underestimate NPP on croplands. A new Agricultural Inventory-based Light Use Efficiency (AgI-LUE) framework was developed to estimate individual crop biophysical parameters for use in estimating crop-specific NPP. The method is documented here and evaluated for corn and soybean crops in Iowa and Illinois inmore » years 2006 and 2007. The method includes a crop-specific enhanced vegetation index (EVI) from the Moderate Resolution Imaging Spectroradiometer (MODIS), shortwave radiation data estimated using Mountain Climate Simulator (MTCLIM) algorithm and crop-specific LUE per county. The combined aforementioned variables were used to generate spatially-resolved, crop-specific NPP that correspond to the Cropland Data Layer (CDL) land cover product. The modeling framework represented well the gradient of NPP across Iowa and Illinois, and also well represented the difference in NPP between years 2006 and 2007. Average corn and soybean NPP from AgI-LUE was 980 g C m-2 yr-1 and 420 g C m-2 yr-1, respectively. This was 2.4 and 1.1 times higher, respectively, for corn and soybean compared to the MOD17A3 NPP product. Estimated gross primary productivity (GPP) derived from AgI-LUE were in close agreement with eddy flux tower estimates. The combination of new inputs and improved datasets enabled the development of spatially explicit and reliable NPP estimates for individual crops over large regional extents.« less

Exploring Global Patterns in Human Appropriation of Net Primary Production Using Earth Observation Satellites and Statistical Data

NASA Astrophysics Data System (ADS)

Imhoff, M.; Bounoua, L.

2004-12-01

A unique combination of satellite and socio-economic data were used to explore the relationship between human consumption and the carbon cycle. Biophysical models were applied to consumption data to estimate the annual amount of Earth's terrestrial net primary production humans require for food, fiber and fuel using the same modeling architecture as satellite-supported NPP measurements. The amount of Earth's NPP required to support human activities is a powerful measure of the aggregate human impacts on the biosphere and indicator of societal vulnerability to climate change. Equations were developed estimating the amount of landscape-level NPP required to generate all the products consumed by 230 countries including; vegetal foods, meat, milk, eggs, wood, fuel-wood, paper and fiber. The amount of NPP required was calculated on a per capita basis and projected onto a global map of population to create a spatially explicit map of NPP-carbon demand in units of elemental carbon. NPP demand was compared to a map of Earth's average annual net primary production or supply created using 17 years (1982-1998) of AVHRR vegetation index to produce a geographically accurate balance sheet of terrestrial NPP-carbon supply and demand. Globally, humans consume 20 percent of Earth's total net primary production on land. Regionally the NPP-carbon balance percentage varies from 6 to over 70 percent and locally from near 0 to over 30,000 percent in major urban areas. The uneven distribution of NPP-carbon supply and demand, indicate the degree to which various human populations rely on NPP imports, are vulnerable to climate change and suggest policy options for slowing future growth in NPP demand.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rafique, Rashid; Zhao, Fang; de Jong, Rogier

The net primary productivity (NPP) is commonly used for understanding the dynamics of terrestrial ecosystems and their role in carbon cycle. We used a combination of the most recent NDVI and model–based NPP estimates (from five models of the TRENDY project) for the period 1982-2012, to study the role of terrestrial ecosystems in carbon cycle under the prevailing climate conditions. We found that 80% and 67% of the global land area showed positive NPP and NDVI values, respectively, for this period. The global NPP was estimated to be about 63 Pg C y -1, with an increase of 0.214 Pgmore » C y -1 y -1. Similarly, the global mean NDVI was estimated to be 0.33, with an increasing trend of 0.00041 y-1. The spatial patterns of NPP and NDVI demonstrated substantial variability, especially at the regional level, for most part of the globe. However, on temporal scale, both global NPP and NDVI showed a corresponding pattern of increase (decrease) for the duration of this study except for few years (e.g. 1990 and 1995-98). Generally, the Northern Hemisphere showed stronger NDVI and NPP increasing trends over time compared to the Southern Hemisphere; however, NDVI showed larger trends in Temperate regions while NPP showed larger trends in Boreal regions. Among the five models, the maximum and minimum NPP were produced by JULES (72.4 Pg C y -1) and LPJ (53.72 Pg C y -1) models, respectively. At latitudinal level, the NDVI and NPP ranges were ~0.035 y -1 to ~-0.016 y -1 and ~0.10 Pg C y -1 y -1 to ~-0.047 Pg C y -1 y -1, respectively. Overall, the results of this study suggest that the modeled NPP generally correspond to the NDVI trends in the temporal dimension. Lastly, the significant variability in spatial patterns of NPP and NDVI trends points to a need for research to understand the causes of these discrepancies between molded and observed ecosystem dynamics, and the carbon cycle.« less

Changing NPP consumption patterns in the Holocene: from Megafauna "liberated" NPP to "ecological bankruptcy"

NASA Astrophysics Data System (ADS)

Doughty, C.

2015-12-01

There have been vast changes in how net primary production (NPP) is consumed by humans and animals during the Holocene beginning with a potential increase in availability following the Pleistocene megafauna extinctions. This was followed by the development of agriculture which began to gradually restrict availability of NPP for wild animals. Finally, humans entered the industrial era using non-plant based energies to power societies. Here I ask the following questions about these three energy transitions: 1. How much NPP energy may have become available following the megafauna extinctions? 2. When did humans, through agriculture and domestic animals, consume more NPP than wild mammals in each country? 3. When did humans and wild mammals use more energy than was available in total NPP in each country? To answer this last question I calculate NPP consumed by wild animals, crops, livestock, and energy use (all converted to units of MJ) and compare this with the total potential NPP (also in MJ) for each country. We develop the term "ecological bankruptcy" to refer to the level of consumption where not all energy needs can be met by the country's NPP. Currently, 82 countries and a net population of 5.4 billion are in the state of ecologically bankruptcy, crossing this threshold at various times over the past 40 years. By contrast, only 52 countries with a net population of 1.2 billion remain ecologically solvent. Overall, the Holocene has seen remarkable changes in consumption patterns of NPP, passing through three distinct phases. Humans began in a world where there was 1.6-4.1% unclaimed NPP to consume. From 1700-1850, humans began to consume more than wild animals (globally averaged). At present, >82% of people live in countries where not even all available plant matter could satisfy our energy demands.

Changes of net primary productivity in China during recent 11 years detected using an ecological model driven by MODIS data

NASA Astrophysics Data System (ADS)

Liu, Yibo; Ju, Weimin; He, Honglin; Wang, Shaoqiang; Sun, Rui; Zhang, Yuandong

2013-03-01

Net primary productivity (NPP) is an important component of the terrestrial carbon cycle. Accurately mapping the spatial-temporal variations of NPP in China is crucial for global carbon cycling study. In this study the process-based Boreal Ecosystem Productivity Simulator (BEPS) was employed to study the changes of NPP in China's ecosystems for the period from 2000 to 2010. The BEPS model was first validated using gross primary productivity (GPP) measured at typical flux sites and forest NPP measured at different regions. Then it was driven with leaf area index (LAI) inversed from the Moderate Resolution Imaging Spectroradiometer (MODIS) reflectance and land cover products and meteorological data interpolated from observations at 753 national basic meteorological stations to simulate NPP at daily time steps and a spatial resolution of 500 m from January 1, 2000 to December 31, 2010. Validations show that BEPS is able to capture the seasonal variations of tower-based GPP and the spatial variability of forest NPP in different regions of China. Estimated national total of annual NPP varied from 2.63 to 2.84Pg C·yr-1, averaging 2.74 Pg C·yr-1 during the study period. Simulated terrestrial NPP shows spatial patterns decreasing from the east to the west and from the south to the north, in association with land cover types and climate. South-west China makes the largest contribution to the national total of NPP while NPP in the North-west account for only 3.97% of the national total. During the recent 11 years, the temporal changes of NPP were heterogamous. NPP increased in 63.8% of China's landmass, mainly in areas north of the Yangtze River and decreased in most areas of southern China, owing to the low temperature freezing in early 2008 and the severe drought in late 2009.

Estimates of Global Rangeland Net Primary Productivity and its Consumption Based on Climate and Livestock Distribution Data

NASA Astrophysics Data System (ADS)

Asrar, G.; Wolf, J.; Rafique, R.; West, T. O.; Ogle, S. M.

2016-12-01

Rangelands play an important role in providing ecosystem services such as food, forage, and fuels in many parts of the world. The net primary productivity (NPP), a difference between CO2 fixed by plants and CO2 lost to autotrophic respiration, is a good indicator of the productivity of rangeland ecosystems, and their contribution to the cycling of carbon in the Earth system. In this study, we estimated the NPP of global rangelands, the consumption thereof by grazing livestock, and associated uncertainties, to better understand and quantify the contribution of rangelands to land-based carbon storage. We estimated rangeland NPP using mean annual precipitation data from Climate Research Unit (CRU), and a regression model based on global observations (Del Grosso et al., 2008). Spatial distributions of annual livestock consumption of rangeland NPP (Wolf et al., 2015) were combined with gridded annual rangeland NPP for the years 2000 - 2011. The uncertainty analysis of these estimates was conducted using a Monte Carlo approach. The rangeland NPP estimates with associated uncertainties were also compared with the total modeled GPP estimates obtained from vegetation dynamic model simulations. Our results showed that mean above-ground NPP of rangelands is 1017.5 MgC/km2, while mean below-ground NPP is 847.6 MgC/km2. The total rangeland NPP represents a significant portion of the total NPP of the terrestrial ecosystem. The livestock area requirements used to geographically distribute livestock spatially are based on optimal pasturage and are low relative to area requirements on less productive land. Even so, ca. 90% of annual livestock consumption of rangeland NPP were met with no adjustment of livestock distributions. Moreover, the results of this study allowed us to explicitly quantify the temporal and spatial variations of rangeland NPP under different climatic conditions. Uncertainty analysis was helpful in identifying the strength and weakness of the methods used to estimate rangeland NPP. Overall, the results from this study are useful in quantifying the contribution of rangelands to the carbon cycle and for providing geospatially distributed carbon fluxes associated with the production and consumption of rangeland biomass.

Ecosystem response to climatic variables - air temperature and precipitation: How can these variables alter plant productions in C4-grass dominant ecosystem?

NASA Astrophysics Data System (ADS)

Jung, C. G.; Jiang, L.; Luo, Y.

2017-12-01

Understanding net primary production (NPP) response to the key climatic variables, temperature and precipitation, is essential since the response could be represented by one of future consequences from ecosystem responses. Under future climatic warming, fluctuating precipitation is expected. In addition, NPP solely could not explain whole ecosystem response; therefore, not only NPP, but also above- and below-ground NPP (ANPP and BNPP, respectively) need to be examined. This examination needs to include how the plant productions response along temperature and precipitation gradients. Several studies have examined the response of NPP against each of single climatic variable, but understanding the response of ANPP and BNPP to the multiple variables is notably poor. In this study, we used the plant productions data (NPP, ANPP, and BNPP) with climatic variables, i.e., air temperature and precipitation, from 1999 to 2015 under warming and clipping treatments (mimicking hay-harvesting) in C4-grass dominant ecosystem located in central Oklahoma, United States. Firstly, we examined the nonlinear relationships with the climatic variables for NPP, ANPP and BNPP; and then predicted possible responses in the temperature - precipitation space by using a linear mixed effect model. Nonlinearities of NPP, ANPP and BNPP to the climatic variables have been found to show unimodal curves, and nonlinear models have better goodness of fit as shown lower Akaike information criterion (AIC) than linear models. Optimum condition for NPP is represented at high temperature and precipitation level whereas BNPP is maximized at moderate precipitation levels while ANPP has same range of NPP's optimum condition. Clipping significantly reduced ANPP while there was no clipping effect on NPP and BNPP. Furthermore, inclining NPP and ANPP have shown in a range from moderate to high precipitation level with increasing temperature while inclining pattern for BNPP was observed in moderate precipitation level. Overall, the C4-grass dominant ecosystem has a potential for considerable increases in NPP in hotter and wetter conditions as shown a range from moderate to high temperature and precipitation levels; ANPP has peaked at the high temperature and precipitation level, but maximum BNPP needs moderate precipitation level and high temperature.

Nutritional geometry of calcium and phosphorus nutrition in broiler chicks. The effect of different dietary calcium and phosphorus concentrations and ratios on nutrient digestibility.

PubMed

Wilkinson, S J; Bradbury, E J; Thomson, P C; Bedford, M R; Cowieson, A J

2014-07-01

A total of 600 Ross 308-day-old male broiler chicks were used in a 28 day digestibility study to investigate the interaction between dietary calcium (Ca) and non-phytate phosphorus (nPP) on the digestibility of minerals and amino acids. Diets were formulated to be nutritionally adequate except for Ca and nPP. Fifteen mash diets based on corn and soya bean meal with varying concentrations of Ca (6.4 to 12.0 g/kg) and nPP (2.4 to 7.0 g/kg) were used. Diets were clustered around total densities of Ca and nPP of 12, 13.5 or 15.0 (g/kg) and within each density, a range of five Ca : nPP ratios (1.14 : 1, 1.5 : 1, 2.0 : 1, 2.75 : 1 and 4.0 : 1) were fed. Birds had free access to feed and water throughout the study. At day 28, birds were euthanised for the determination of apparent ileal mineral and amino acid digestibility. Data were modelled in R version 2.15 using a linear mixed-effects model and interrogation of the data was performed by fitting a low order polynomial function. At high Ca concentrations, increasing nPP led to an increase in the apparent digestibility of minerals. Apparent ileal digestibility of phosphorus (P) was enhanced with increasing dietary nPP up to 5.5 g/kg beyond which no improvements were found. Maximal Ca digestibility was found in diets with >8.0 g/kg Ca with concomitant low concentrations of nPP. Diets with a broader Ca : nPP ratio improved the digestibility of Ca but were deleterious to the digestibility of P. In this study, apparent digestibility of amino acids was broadly unaffected by dietary Ca and nPP concentrations. However, interactions between Ca and nPP were observed for the digestibility of glutamine, tyrosine and methionine (all P<0.001). Nitrogen digestibility showed discrete optima around 10.0 and 5.0 g/kg nPP and Na digestibility was maximised around 8 to 9.0 g/kg Ca and 4.5 to 5.4 g/kg nPP. These data show that the ratio of Ca : nPP is more influential to mineral digestibility than the absolute dietary concentration of each macro mineral.

Relationships between net primary productivity and stand age for several forest types and their influence on China's carbon balance.

PubMed

Wang, Shaoqiang; Zhou, Lei; Chen, Jingming; Ju, Weimin; Feng, Xianfeng; Wu, Weixing

2011-06-01

Affected by natural and anthropogenic disturbances such as forest fires, insect-induced mortality and harvesting, forest stand age plays an important role in determining the distribution of carbon pools and fluxes in a variety of forest ecosystems. An improved understanding of the relationship between net primary productivity (NPP) and stand age (i.e., age-related increase and decline in forest productivity) is essential for the simulation and prediction of the global carbon cycle at annual, decadal, centurial, or even longer temporal scales. In this paper, we developed functions describing the relationship between national mean NPP and stand age using stand age information derived from forest inventory data and NPP simulated by the BEPS (Boreal Ecosystem Productivity Simulator) model in 2001. Due to differences in ecobiophysical characteristics of different forest types, NPP-age equations were developed for five typical forest ecosystems in China (deciduous needleleaf forest (DNF), evergreen needleleaf forest in tropic and subtropical zones (ENF-S), deciduous broadleaf forest (DBF), evergreen broadleaf forest (EBF), and mixed broadleaf forest (MBF)). For DNF, ENF-S, EBF, and MBF, changes in NPP with age were well fitted with a common non-linear function, with R(2) values equal to 0.90, 0.75, 0.66, and 0.67, respectively. In contrast, a second order polynomial was best suitable for simulating the change of NPP for DBF, with an R(2) value of 0.79. The timing and magnitude of the maximum NPP varied with forest types. DNF, EBF, and MBF reached the peak NPP at the age of 54, 40, and 32 years, respectively, while the NPP of ENF-S maximizes at the age of 13 years. The highest NPP of DBF appeared at 122 years. NPP was generally lower in older stands with the exception of DBF, and this particular finding runs counter to the paradigm of age-related decline in forest growth. Evaluation based on measurements of NPP and stand age at the plot-level demonstrates the reliability and applicability of the fitted NPP-age relationships. These relationships were used to replace the normalized NPP-age relationship used in the original InTEC (Integrated Terrestrial Ecosystem Carbon) model, to improve the accuracy of estimated carbon balance for China's forest ecosystems. With the revised NPP-age relationship, the InTEC model simulated a larger carbon source from 1950-1980 and a larger carbon sink from 1985-2001 for China's forests than the original InTEC model did because of the modification to the age-related carbon dynamics in forests. This finding confirms the importance of considering the dynamics of NPP related to forest age in estimating regional and global terrestrial carbon budgets. Copyright © 2011 Elsevier Ltd. All rights reserved.

Research subjects for analytical estimation of core degradation at Fukushima-Daiichi nuclear power plant

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nagase, F.; Ishikawa, J.; Kurata, M.

2013-07-01

Estimation of the accident progress and status inside the pressure vessels (RPV) and primary containment vessels (PCV) is required for appropriate conductance of decommissioning in the Fukushima-Daiichi NPP. For that, it is necessary to obtain additional experimental data and revised models for the estimation using computer codes with increased accuracies. The Japan Atomic Energy Agency (JAEA) has selected phenomena to be reviewed and developed, considering previously obtained information, conditions specific to the Fukushima-Daiichi NPP accident, and recent progress of experimental and analytical technologies. As a result, research and development items have been picked up in terms of thermal-hydraulic behavior inmore » the RPV and PCV, progression of fuel bundle degradation, failure of the lower head of RPV, and analysis of the accident. This paper introduces the selected phenomena to be reviewed and developed, research plans and recent results from the JAEA's corresponding research programs. (authors)« less

Comparison of Aerial and Terrestrial Remote Sensing Techniques for Quantifying Forest Canopy Structural Complexity and Estimating Net Primary Productivity

NASA Astrophysics Data System (ADS)

Fahey, R. T.; Tallant, J.; Gough, C. M.; Hardiman, B. S.; Atkins, J.; Scheuermann, C. M.

2016-12-01

Canopy structure can be an important driver of forest ecosystem functioning - affecting factors such as radiative transfer and light use efficiency, and consequently net primary production (NPP). Both above- (aerial) and below-canopy (terrestrial) remote sensing techniques are used to assess canopy structure and each has advantages and disadvantages. Aerial techniques can cover large geographical areas and provide detailed information on canopy surface and canopy height, but are generally unable to quantitatively assess interior canopy structure. Terrestrial methods provide high resolution information on interior canopy structure and can be cost-effectively repeated, but are limited to very small footprints. Although these methods are often utilized to derive similar metrics (e.g., rugosity, LAI) and to address equivalent ecological questions and relationships (e.g., link between LAI and productivity), rarely are inter-comparisons made between techniques. Our objective is to compare methods for deriving canopy structural complexity (CSC) metrics and to assess the capacity of commonly available aerial remote sensing products (and combinations) to match terrestrially-sensed data. We also assess the potential to combine CSC metrics with image-based analysis to predict plot-based NPP measurements in forests of different ages and different levels of complexity. We use combinations of data from drone-based imagery (RGB, NIR, Red Edge), aerial LiDAR (commonly available medium-density leaf-off), terrestrial scanning LiDAR, portable canopy LiDAR, and a permanent plot network - all collected at the University of Michigan Biological Station. Our results will highlight the potential for deriving functionally meaningful CSC metrics from aerial imagery, LiDAR, and combinations of data sources. We will also present results of modeling focused on predicting plot-level NPP from combinations of image-based vegetation indices (e.g., NDVI, EVI) with LiDAR- or image-derived metrics of CSC (e.g., rugosity, porosity), canopy density, (e.g., LAI), and forest structure (e.g., canopy height). This work builds toward future efforts that will use other data combinations, such as those available at NEON sites, and could be used to inform and test popular ecosystem models (e.g., ED2) incorporating structure.

Fertility intentions, power relations and condom use within intimate and other non-paying partnerships of women in sex work in Bagalkot District, South India.

PubMed

Deering, Kathleen N; Shaw, Souradet Y; Thompson, Laura H; Ramanaik, Satyanarayana; Raghavendra, T; Doddamane, Mahesh; Bhattacharjee, Parinita; Moses, Stephen; Lorway, Robert

2015-01-01

This study aimed to: (1) examine the relationship between interpersonal as well as social-demographic, cultural and structural factors, and condom non-use by sex workers' main intimate or other non-paying male sex partners (NPPs), as reported by a sample of sex workers (SWs); and (2) understand HIV/sexually transmitted infections (STIs) risk (e.g., numbers of sexual partners; condom use with different partners) among couples comprised of a sub-set of SWs and their NPPs. Bivariate and multivariable logistic regression was used to identify factors associated with condom non-use at last sex by the main NPP, as reported by SWs. Adjusted odds ratios and 95% confidence intervals are reported (AOR[95%CIs]). Data were drawn from cross-sectional surveys in Bagalkot District, Karnataka State, South India. Responses by SWs whose main NPPs agreed to enrol in the study and the main NPP enroled were linked; these responses by couples (pairs of SWs and NPPs) were examined to assess sexual risk for HIV/STIs. Overall, this study included 257 SWs and 76 NPPs. The data from 67 couples (88.2%) could be linked. In over a quarter of partnerships, at least one (SW or NPP) partner reported having another type of partner besides each other (and clients of SWs). In multivariable analysis, significantly increased odds of condom non-use at last sex with the main NPP were found for the following key factors: planning to have a child with their main NPP (AOR = 3.71[1.44-9.58]); and having decisions about condom use made by their main NPP (AOR = 9.87[4.03-24.16]) or both equally (AOR = 3.18[1.39-7.80]) (versus by the SWs herself). Our study highlights the potential risk for HIV/STI acquisition and transmission between NPPs and SWs, and between NPPs and their non-SWs wives and other sex partners. Study results underscore the need for HIV/STI prevention approaches that incorporate informed decision-making about childbearing and parenting, and empowerment strategies for SWs in the context of their relationships with NPPs.

NPP4 is a procoagulant enzyme on the surface of vascular endothelium

PubMed Central

Albright, Ronald A.; Chang, William C.; Robert, Donna; Ornstein, Deborah L.; Cao, Wenxiang; Liu, Lynn; Redick, Meredith E.; Young, J. Isaac; De La Cruz, Enrique M.

2012-01-01

Ap3A is a platelet-dense granule component released into the extracellular space during the second wave of platelet aggregation on activation. Here, we identify an uncharacterized enzyme, nucleotide pyrophosphatase/phosphodiesterase-4 (NPP4), as a potent hydrolase of Ap3A capable of stimulating platelet aggregation and secretion. We demonstrate that NPP4 is present on the surface of vascular endothelium, where it hydrolyzes Ap3A into AMP and ADP, and Ap4A into AMP and ATP. Platelet aggregation assays with citrated platelet-rich plasma reveal that the primary and secondary waves of aggregation and dense granule release are strongly induced by nanomolar NPP4 in a concentration-dependent manner in the presence of Ap3A, while Ap3A alone initiates a primary wave of aggregation followed by rapid disaggregation. NPP2 and an active site NPP4 mutant, neither of which appreciably hydrolyzes Ap3A, have no effect on platelet aggregation and secretion. Finally, by using ADP receptor blockade we confirm that NPP4 mediates platelet aggregation via release of ADP from Ap3A and activation of ADP receptors. Collectively, these studies define the biologic and enzymatic basis for NPP4 and Ap3A activity in platelet aggregation in vitro and suggest that NPP4 promotes hemostasis in vivo by augmenting ADP-mediated platelet aggregation at the site of vascular injury. PMID:22995898

Ectonucleotide pyrophosphatase/phosphodiesterase (E-NPP) and adenosine deaminase (ADA) activities in prostate cancer patients: influence of Gleason score, treatment and bone metastasis.

PubMed

Battisti, Vanessa; Maders, Liési D K; Bagatini, Margarete D; Battisti, Iara E; Bellé, Luziane P; Santos, Karen F; Maldonado, Paula A; Thomé, Gustavo R; Schetinger, Maria R C; Morsch, Vera M

2013-04-01

The relation between adenine nucleotides and cancer has already been described in literature. Considering that the enzymes ectonucleotide pyrophosphatase/phosphodiesterase (E-NPP) and adenosine deaminase (ADA) act together to control nucleotide levels, we aimed to investigate the role of these enzymes in prostate cancer (PCa). E-NPP and ADA activities were determined in serum and platelets of PCa patients and controls. We also verified the influence of the Gleason score, bone metastasis and treatment in the enzyme activities. Platelets and serum E-NPP activity increased, whereas ADA activity in serum decreased in PCa patients. In addition, Gleason score, metastasis and treatment influenced E-NPP and ADA activities. We may propose that E-NPP and ADA are involved in the development of PCa. Moreover, E-NPP and ADA activities are modified in PCa patients with distinct Gleason score, with bone metastasis, as well as in patients under treatment. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

Technology for NPP decantate treatment realized at Kola NPP

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stakhiv, Michael; Avezniyazov, Slava; Savkin, Alexander

2007-07-01

At Moscow SIA 'Radon' jointly with JSC 'Alliance Gamma', the technology for NPP Decantate Treatment was developed, tested and realized at Kola NPP. This technology consists of dissolving the salt residue and subsequent treatment by ozonization, separation of the deposits formed from ozonization and selective cleaning by ferro-cyanide sorbents. The nonactive salt solution goes to an industrial waste disposal site or a repository specially developed at NPP sites for 'exempt waste' products by IAEA classification. This technology was realized at Kola NPP in December 2006 year. At this time more than 1000 m{sup 3} of decantates log time stored aremore » treated. It allows solving very old problem to empty decantates' tanks at NPPs in environmentally safe manner and with high volume reduction factor. (authors)« less

Early Assessment of VIIRS On-Orbit Calibration and Support Activities

NASA Technical Reports Server (NTRS)

Xiong, Xiaoxiong; Chiang, Kwofu; McIntire, Jeffrey; Oudrari, Hassan; Wu, Aisheng; Schwaller, Mathew; Butler, James

2012-01-01

The Suomi National Polar-orbiting Partnership (S-NPP) satellite, formally the National Polar-orbiting Operational Environmental Satellite System (NPOESS) Preparatory Project (NPP), provides a bridge between current and future low-Earth orbiting weather and environmental observation satellite systems. The NASA s NPP VIIRS Characterization Support Team (VCST) is designed to assess the long term geometric and radiometric performance of the Visible Infrared Imaging Radiometer Suite (VIIRS) instrument onboard the S-NPP spacecraft and to support NPP Science Team Principal Investigators (PI) for their independent evaluation of VIIRS Environmental Data Records (EDRs). This paper provides an overview of Suomi NPP VIIRS on-orbit calibration activities and examples of sensor initial on-orbit performance. It focuses on the radiometric calibration support activities and capabilities provided by the NASA VCST.

Estimating cropland NPP using national crop inventory and MODIS derived crop specific parameters

NASA Astrophysics Data System (ADS)

Bandaru, V.; West, T. O.; Ricciuto, D. M.

2011-12-01

Estimates of cropland net primary production (NPP) are needed as input for estimates of carbon flux and carbon stock changes. Cropland NPP is currently estimated using terrestrial ecosystem models, satellite remote sensing, or inventory data. All three of these methods have benefits and problems. Terrestrial ecosystem models are often better suited for prognostic estimates rather than diagnostic estimates. Satellite-based NPP estimates often underestimate productivity on intensely managed croplands and are also limited to a few broad crop categories. Inventory-based estimates are consistent with nationally collected data on crop yields, but they lack sub-county spatial resolution. Integrating these methods will allow for spatial resolution consistent with current land cover and land use, while also maintaining total biomass quantities recorded in national inventory data. The main objective of this study was to improve cropland NPP estimates by using a modification of the CASA NPP model with individual crop biophysical parameters partly derived from inventory data and MODIS 8day 250m EVI product. The study was conducted for corn and soybean crops in Iowa and Illinois for years 2006 and 2007. We used EVI as a linear function for fPAR, and used crop land cover data (56m spatial resolution) to extract individual crop EVI pixels. First, we separated mixed pixels of both corn and soybean that occur when MODIS 250m pixel contains more than one crop. Second, we substituted mixed EVI pixels with nearest pure pixel values of the same crop within 1km radius. To get more accurate photosynthetic active radiation (PAR), we applied the Mountain Climate Simulator (MTCLIM) algorithm with the use of temperature and precipitation data from the North American Land Data Assimilation System (NLDAS-2) to generate shortwave radiation data. Finally, county specific light use efficiency (LUE) values of each crop for years 2006 to 2007 were determined by application of mean county inventory NPP and EVI-derived APAR into the Monteith equation. Results indicate spatial variability in LUE values across Iowa and Illinois. Northern regions of both Iowa and Illinois have higher LUE values than southern regions. This trend is reflected in NPP estimates. Results also show that corn has higher LUE values than soybean, resulting in higher NPP for corn than for soybean. Current NPP estimates were compared with NPP estimates from MOD17A3 product and with county inventory-based NPP estimates. Results indicate that current NPP estimates closely agree with inventory-based estimates, and that current NPP estimates are higher than those of the MOD17A3 product. It was also found that when mixed pixels were substituted with nearest pure pixels, revised NPP estimates were improved showing better agreement with inventory-based estimates.

An Algorithm For Climate-Quality Atmospheric Profiling Continuity From EOS Aqua To Suomi-NPP

NASA Astrophysics Data System (ADS)

Moncet, J. L.

2015-12-01

We will present results from an algorithm that is being developed to produce climate-quality atmospheric profiling earth system data records (ESDRs) for application to hyperspectral sounding instrument data from Suomi-NPP, EOS Aqua, and other spacecraft. The current focus is on data from the S-NPP Cross-track Infrared Sounder (CrIS) and Advanced Technology Microwave Sounder (ATMS) instruments as well as the Atmospheric InfraRed Sounder (AIRS) on EOS Aqua. The algorithm development at Atmospheric and Environmental Research (AER) has common heritage with the optimal estimation (OE) algorithm operationally processing S-NPP data in the Interface Data Processing Segment (IDPS), but the ESDR algorithm has a flexible, modular software structure to support experimentation and collaboration and has several features adapted to the climate orientation of ESDRs. Data record continuity benefits from the fact that the same algorithm can be applied to different sensors, simply by providing suitable configuration and data files. The radiative transfer component uses an enhanced version of optimal spectral sampling (OSS) with updated spectroscopy, treatment of emission that is not in local thermodynamic equilibrium (non-LTE), efficiency gains with "global" optimal sampling over all channels, and support for channel selection. The algorithm is designed for adaptive treatment of clouds, with capability to apply "cloud clearing" or simultaneous cloud parameter retrieval, depending on conditions. We will present retrieval results demonstrating the impact of a new capability to perform the retrievals on sigma or hybrid vertical grid (as opposed to a fixed pressure grid), which particularly affects profile accuracy over land with variable terrain height and with sharp vertical structure near the surface. In addition, we will show impacts of alternative treatments of regularization of the inversion. While OE algorithms typically implement regularization by using background estimates from climatological or numerical forecast data, those sources are problematic for climate applications due to the imprint of biases from past climate analyses or from model error.

Effect of dietary phosphorus, phytase, and 25-hydroxycholecalciferol on broiler chicken bone mineralization, litter phosphorus, and processing yields.

PubMed

Angel, R; Saylor, W W; Mitchell, A D; Powers, W; Applegate, T J

2006-07-01

Three floor pen experiments (Exp) were conducted to evaluate low nonphytin P (NPP) concentrations and the NPP sparing effect of phytase (PHY) and 25-hydroxycholecalciferol (25D) on bone mineralization, bone breaking during commercial processing, litter P, and water-soluble P (WSP) concentrations. Tested treatments (TRT) were control, National Research Council NPP; University of Maryland (UMD) NPP; UMD + PHY, UMD NPP reduced by 0.064% NPP + 600 U of PHY/kg; UMD + PHY + 25D, UMD NPP reduced by 0.090% NPP + 600 U of PHY and 70 microg of 25D/kg; control + PHY mimicked the industry practice of diets by 0.1% when PHY is added; and negative control with 90% UMD NPP concentrations. UMD + PHY and control + PHY diets contained 600 U of PHY/kg, and UMD + PHY + 25D contained 600 U of PHY + 70 microg of 25D/kg. Performance results were presented separately. After each Exp, litter P and WSP were determined, and bone measurements were obtained on 8 or 10 broilers per pen. Tested TRT did not affect broiler BW. Femur ash weight of broilers fed the UMD and UMD + PHY + 25D was lower in all Exp compared with that of broilers fed the control diet. Femur ash was similar for control and UMD + PHY broilers, yet averaged over all Exp, UMD + PHY broilers consumed 39% less NPP and required less NPP per gram of femur ash than those on the control (4.87 and 7.77 g of NPP/g of ash, Exp 3). At the end of Exp 3, broilers were processed in a commercial facility. Despite reductions in NPP intake and bone mineralization, no differences were observed in measurements of economic importance (parts lost, carcass yield, and incidence of broken bones). The P excretion per bird was lowest for birds fed the UMD + PHY + 25D diet followed by those fed the UMD + PHY and negative control diets (10.44, 12.00, and 13.78 g of P/bird, respectively) and were highest for those fed the control diet (19.55 g of P/bird). These results suggest that feeding diets low in P together with PHY and 25D will not affect performance or increase losses at processing while resulting in improved P retention and reductions in P and WSP excreted.

Global and regional variability and change in terrestrial ecosystems net primary production and NDVI: A model-data comparison

DOE PAGES

Rafique, Rashid; Zhao, Fang; de Jong, Rogier; ...

2016-02-25

The net primary productivity (NPP) is commonly used for understanding the dynamics of terrestrial ecosystems and their role in carbon cycle. We used a combination of the most recent NDVI and model–based NPP estimates (from five models of the TRENDY project) for the period 1982-2012, to study the role of terrestrial ecosystems in carbon cycle under the prevailing climate conditions. We found that 80% and 67% of the global land area showed positive NPP and NDVI values, respectively, for this period. The global NPP was estimated to be about 63 Pg C y -1, with an increase of 0.214 Pgmore » C y -1 y -1. Similarly, the global mean NDVI was estimated to be 0.33, with an increasing trend of 0.00041 y-1. The spatial patterns of NPP and NDVI demonstrated substantial variability, especially at the regional level, for most part of the globe. However, on temporal scale, both global NPP and NDVI showed a corresponding pattern of increase (decrease) for the duration of this study except for few years (e.g. 1990 and 1995-98). Generally, the Northern Hemisphere showed stronger NDVI and NPP increasing trends over time compared to the Southern Hemisphere; however, NDVI showed larger trends in Temperate regions while NPP showed larger trends in Boreal regions. Among the five models, the maximum and minimum NPP were produced by JULES (72.4 Pg C y -1) and LPJ (53.72 Pg C y -1) models, respectively. At latitudinal level, the NDVI and NPP ranges were ~0.035 y -1 to ~-0.016 y -1 and ~0.10 Pg C y -1 y -1 to ~-0.047 Pg C y -1 y -1, respectively. Overall, the results of this study suggest that the modeled NPP generally correspond to the NDVI trends in the temporal dimension. Lastly, the significant variability in spatial patterns of NPP and NDVI trends points to a need for research to understand the causes of these discrepancies between molded and observed ecosystem dynamics, and the carbon cycle.« less

[Characteristics of terrestrial ecosystem primary productivity in East Asia based on remote sensing and process-based model].

PubMed

Zhang, Fang-Min; Ju, Wei-Min; Chen, Jing-Ming; Wang, Shao-Qiang; Yu, Gui-Rui; Han, Shi-Jie

2012-02-01

Based on the bi-linearly interpolated meteorological reanalysis data from National Centers for Environmental Prediction, USA and by using the leaf area index data derived from the GIMMS NDVI to run the process-based Boreal Ecosystems Productivity Simulator (BEPS) model, this paper simulated and analyzed the spatiotemporal characteristics of the terrestrial ecosystem gross primary productivity (GPP) and net primary productivity (NPP) in East Asia in 2000-2005. Before regional simulating and calculating, the observation GPP data of different terrestrial ecosystem in 15 experimental stations of AsiaFlux network and the inventory measurements of NPP at 1300 sampling sites were applied to validate the BEPS GPP and NPP. The results showed that BEPS could well simulate the changes in GPP and NPP of different terrestrial ecosystems, with the R2 ranging from 0.86 to 0.99 and the root mean square error (RMSE) from 0.2 to 1.2 g C x m(-2) x d(-1). The simulated values by BEPS could explain 78% of the changes in annual NPP, and the RMSE was 118 g C x m(-2) x a(-1). In 2000-2005, the averaged total GPP and total NPP of the terrestrial ecosystems in East Asia were 21.7 and 10.5 Pg C x a(-1), respectively, and the GPP and NPP exhibited similar spatial and temporal variation patterns. During the six years, the total NPP of the terrestrial ecosystems varied from 10.2 to 10.7 Pg C x a(-1), with a coefficient of variation being 2. 2%. High NPP (above 1000 g C x m(-2) x a(-1)) occurred in the southeast island countries, while low NPP (below 30 g C x m(-2) x a(-1)) occurred in the desert area of Northwest China. The spatial patterns of NPP were mainly attributed to the differences in the climatic variables across East Asia. The NPP per capita also varied greatly among different countries, which was the highest (70217 kg C x a(-1)) in Mongolia, far higher than that (1921 kg C x a(-1)) in China, and the lowest (757 kg C x a(-1)) in India.

Record of C4 Photosynthesis Through the Late Neogene and Pleistocene

NASA Astrophysics Data System (ADS)

Cerling, T. E.

2016-12-01

C4 photosynthesis is an adaptation to the low atmospheric carbon dioxide concentrations experienced in the Neogene; it is found principally in tropical to sub-tropical/temperate regions where temperatures are high in the growing season. Although C4 photosynthesis makes up about 50% of Net Primary Productivity in tropical regions, its macroscopic fossil record is extremely sparse. Therefore, inferences to its significance in local ecosystems are based primarily on stable isotopes, with phytoliths become more important as phytolith morphology becomes better associated with plant structure and classification. Stable isotopes have been the principal recorder for understanding the history of C4 photosynthesis; however, different materials record different aspects of the C4 contribution to ecosystem structure and thus are telling different parts of the same story. With the fossil record so poorly known, we often assume similar ecosystem structures and functions as we observe in modern analogues. It is likely that large evolutionary changes have taken place within C4 plants as they went from < 1% tropical NPP to > 50% tropical NPP in the late Neogene.

Metabolic engineering of monoterpene biosynthesis in tomato fruits via introduction of the non-canonical substrate neryl diphosphate.

PubMed

Gutensohn, Michael; Nguyen, Thuong T H; McMahon, Richard D; Kaplan, Ian; Pichersky, Eran; Dudareva, Natalia

2014-07-01

Recently it was shown that monoterpenes in tomato trichomes (Solanum lycopersicum) are synthesized by phellandrene synthase 1 (PHS1) from the non-canonical substrate neryl diphosphate (NPP), the cis-isomer of geranyl diphosphate (GPP). As PHS1 accepts both NPP and GPP substrates forming different monoterpenes, it was overexpressed in tomato fruits to test if NPP is also available in a tissue highly active in carotenoid production. However, transgenic fruits overexpressing PHS1 produced only small amounts of GPP-derived PHS1 monoterpene products, indicating the absence of endogenous NPP. Therefore, NPP formation was achieved by diverting the metabolic flux from carotenoids via expression of tomato neryl diphosphate synthase 1 (NDPS1). NDPS1 transgenic fruits produced NPP-derived monoterpenes, including nerol, neral and geranial, while displaying reduced lycopene content. NDPS1 co-expression with PHS1 resulted in a monoterpene blend, including β-phellandrene, similar to that produced from NPP by PHS1 in vitro and in trichomes. Unexpectedly, PHS1×NDPS1 fruits showed recovery of lycopene levels compared to NDPS1 fruits, suggesting that redirection of metabolic flux is only partially responsible for the reduction in carotenoids. In vitro assays demonstrated that NPP serves as an inhibitor of geranylgeranyl diphosphate synthase, thus its consumption by PHS1 leads to recovery of lycopene levels. Monoterpenes produced in PHS1×NDPS1 fruits contributed to direct plant defense negatively affecting feeding behavior of the herbivore Helicoverpa zea and displaying antifungal activity against Botrytis cinerea. These results show that NPP-derived terpenoids can be produced in plant tissues; however, NPP has to be consumed to avoid negative impacts on plant metabolism. Copyright © 2014 International Metabolic Engineering Society. Published by Elsevier Inc. All rights reserved.

An assessment of net primary productivity estimates using coupled physical-biogeochemical/earth system models in the Arctic Ocean

NASA Astrophysics Data System (ADS)

Lee, Y. J.; Matrai, P.; Friedrichs, M. A.; Saba, V. S.

2016-02-01

Net primary production (NPP) is the major source of energy for the Arctic Ocean (AO) ecosystem, as in most ecosystems. Reproducing current patterns of NPP is essential to understand the physical and biogeochemical controls in the present and the future AO. The Primary Productivity Algorithm Round Robin (PPARR) activity provides a framework to evaluate the skill and sensitivity of NPP as estimated by coupled global/regional climate models and earth system models in the AO. Here we compare results generated from 18 global/regional climate models and three earth system models with observations from a unique pan-Arctic data set (1959-2011) that includes in situ NPP (N=928 stations) and nitrate (N=678 stations). Models results showed a distribution similar to the in situ data distribution, except for the high values of integrated NPP data. Model skill of integrated NPP exhibited little difference as a function of sea ice condition (ice-free vs. ice-covered) and depth (shallow vs. deep), but performance of models varied significantly as a function of seasons. For example, simulated integrated NPP was underestimated in the beginning of the production season (April-June) compared to mid-summer (July and August) and had the highest variability in late summer and early fall (September-October). While models typically underestimated mean NPP, nitrate concentrations were overestimated. Overall, models performed better in reproducing nitrate than NPP in terms of differences in variability. The model performance was similar at all depths within the top 100 m, both in NPP and nitrate. Continual feedback, modification and improvement of the participating models and the resulting increase in model skill are the primary goals of the PPARR-5 AO exercise.

KSC-2011-6567

NASA Image and Video Library

2011-07-28

VANDENBERG AIR FORCE BASE, Calif. -- At Vandenberg Air Force Base in California, a solid rocket motor for the United Launch Alliance Delta II that will carry NASA's National Polar-orbiting Operational Environmental Satellite System Preparatory Project (NPP) satellite is hoisted up at NASA's Space Launch Complex-2. NPP represents a critical first step in building the next-generation of Earth-observing satellites. NPP will carry the first of the new sensors developed for this satellite fleet, now known as the Joint Polar Satellite System (JPSS) to be launched in 2016. NPP is the bridge between NASA's Earth Observing System (EOS) satellites and the forthcoming series of JPSS satellites. The mission will test key technologies and instruments for the JPSS missions. NPP is targeted to launch Oct. 25. For more information, visit http://www.nasa.gov/NPP. Photo credit: NASA/VAFB, Dan Liberotti

KSC-2011-6570

NASA Image and Video Library

2011-07-28

VANDENBERG AIR FORCE BASE, Calif. -- At Vandenberg Air Force Base in California, technicians check the position of a solid rocket motor for the United Launch Alliance Delta II that will carry NASA's National Polar-orbiting Operational Environmental Satellite System Preparatory Project (NPP) satellite at NASA's Space Launch Complex-2. NPP represents a critical first step in building the next-generation of Earth-observing satellites. NPP will carry the first of the new sensors developed for this satellite fleet, now known as the Joint Polar Satellite System (JPSS) to be launched in 2016. NPP is the bridge between NASA's Earth Observing System (EOS) satellites and the forthcoming series of JPSS satellites. The mission will test key technologies and instruments for the JPSS missions. NPP is targeted to launch Oct. 25. For more information, visit http://www.nasa.gov/NPP. Photo credit: NASA/VAFB, Dan Liberotti

KSC-2011-6574

NASA Image and Video Library

2011-07-28

VANDENBERG AIR FORCE BASE, Calif. -- At Vandenberg Air Force Base in California, technicians use a crane to lift a solid rocket motor for the United Launch Alliance Delta II that will carry NASA's National Polar-orbiting Operational Environmental Satellite System Preparatory Project (NPP) satellite at NASA's Space Launch Complex-2. NPP represents a critical first step in building the next-generation of Earth-observing satellites. NPP will carry the first of the new sensors developed for this satellite fleet, now known as the Joint Polar Satellite System (JPSS) to be launched in 2016. NPP is the bridge between NASA's Earth Observing System (EOS) satellites and the forthcoming series of JPSS satellites. The mission will test key technologies and instruments for the JPSS missions. NPP is targeted to launch Oct. 25. For more information, visit http://www.nasa.gov/NPP. Photo credit: NASA/VAFB, Dan Liberotti

KSC-2011-6576

NASA Image and Video Library

2011-07-28

VANDENBERG AIR FORCE BASE, Calif. -- At Vandenberg Air Force Base in California, technicians use a crane to lift a solid rocket motor for the United Launch Alliance Delta II that will carry NASA's National Polar-orbiting Operational Environmental Satellite System Preparatory Project (NPP) satellite at NASA's Space Launch Complex-2. NPP represents a critical first step in building the next-generation of Earth-observing satellites. NPP will carry the first of the new sensors developed for this satellite fleet, now known as the Joint Polar Satellite System (JPSS) to be launched in 2016. NPP is the bridge between NASA's Earth Observing System (EOS) satellites and the forthcoming series of JPSS satellites. The mission will test key technologies and instruments for the JPSS missions. NPP is targeted to launch Oct. 25. For more information, visit http://www.nasa.gov/NPP. Photo credit: NASA/VAFB, Dan Liberotti

KSC-2011-6575

NASA Image and Video Library

2011-07-28

VANDENBERG AIR FORCE BASE, Calif. -- At Vandenberg Air Force Base in California, technicians use a crane to lift a solid rocket motor for the United Launch Alliance Delta II that will carry NASA's National Polar-orbiting Operational Environmental Satellite System Preparatory Project (NPP) satellite at NASA's Space Launch Complex-2. NPP represents a critical first step in building the next-generation of Earth-observing satellites. NPP will carry the first of the new sensors developed for this satellite fleet, now known as the Joint Polar Satellite System (JPSS) to be launched in 2016. NPP is the bridge between NASA's Earth Observing System (EOS) satellites and the forthcoming series of JPSS satellites. The mission will test key technologies and instruments for the JPSS missions. NPP is targeted to launch Oct. 25. For more information, visit http://www.nasa.gov/NPP. Photo credit: NASA/VAFB, Dan Liberotti

KSC-2011-7545

NASA Image and Video Library

2011-10-26

VANDENBERG AIR FORCE BASE, Calif. -- Tim Dunn, NASA launch director, Kennedy Space Center, Fla., participates in the prelaunch news conference at Vandenberg Air Force Base, Calif., for NASA’s National Polar-orbiting Operational Environmental Satellite System Preparatory Project (NPP) spacecraft. NPP represents a critical first step in building the next-generation of Earth-observing satellites. NPP will carry the first of the new sensors developed for this satellite fleet, now known as the Joint Polar Satellite System (JPSS), to be launched in 2016. NPP is the bridge between NASA's Earth Observing System (EOS) satellites and the forthcoming series of JPSS satellites. The mission will test key technologies and instruments for the JPSS missions. NPP is targeted to launch Oct. 28 from Space Launch Complex-2 aboard a United Launch Alliance Delta II rocket. For more information, visit http://www.nasa.gov/NPP. Photo credit: NASA/VAFB

KSC-2011-7542

NASA Image and Video Library

2011-10-26

VANDENBERG AIR FORCE BASE, Calif. -- A model of the NASA’s National Polar-orbiting Operational Environmental Satellite System Preparatory Project (NPP) spacecraft is displayed during the prelaunch news conference at Vandenberg Air Force Base, Calif. NPP represents a critical first step in building the next-generation of Earth-observing satellites. NPP will carry the first of the new sensors developed for this satellite fleet, now known as the Joint Polar Satellite System (JPSS), to be launched in 2016. NPP is the bridge between NASA's Earth Observing System (EOS) satellites and the forthcoming series of JPSS satellites. The mission will test key technologies and instruments for the JPSS missions. NPP is targeted to launch Oct. 28 from Space Launch Complex-2 aboard a United Launch Alliance Delta II rocket. For more information, visit http://www.nasa.gov/NPP. Photo credit: NASA/VAFB

Satellite Supported Estimates of Human Rate of NPP Carbon Use on Land: Challenges Ahead

NASA Astrophysics Data System (ADS)

Imhoff, M. L.; Bounoua, L.; Zhang, P.; Wolfe, R. E.

2010-12-01

The human demand for products of photosynthesis is a powerful measure of the aggregate impact of human action on the biosphere and indicator of societal vulnerability to climate change. We show results from several studies that use satellite and statistical data to estimate the amount of Earth’s net primary production (NPP) on land required to support regional and global use of food, fiber and NPP-based fuel products across a ten-year period. Earth’s planetary NPP ‘supply’ was estimated using AVHRR vegetation index and MODIS derived NPP products to establish a baseline extending from 1982 - 2005. NPP carbon ‘demand’ was estimated by applying biophysical models to consumption data from the UN Food and Agriculture Organization to calculate the annual amount of NPP required for the products consumed. Results show that globally, humans consume more than 20% of Earth’s total net primary production on land and that both populations and per capita consumption increased between 1995 and 2005. Regionally, the NPP-carbon balance percentage varies from 6% to over 70% and locally from near 0% to over 30,000% in major urban areas. Large uncertainties exist in both supply and demand calculations but while the supply trend varies in sign demand continues to rise. Scenarios modeling the impact of per capita consumption, population growth, and technology suggest that NPP demand as percent of supply is likely to increase substantially in the next 40 years despite better harvesting and processing efficiencies.

An Accurate Absorption-Based Net Primary Production Model for the Global Ocean

NASA Astrophysics Data System (ADS)

Silsbe, G.; Westberry, T. K.; Behrenfeld, M. J.; Halsey, K.; Milligan, A.

2016-02-01

As a vital living link in the global carbon cycle, understanding how net primary production (NPP) varies through space, time, and across climatic oscillations (e.g. ENSO) is a key objective in oceanographic research. The continual improvement of ocean observing satellites and data analytics now present greater opportunities for advanced understanding and characterization of the factors regulating NPP. In particular, the emergence of spectral inversion algorithms now permits accurate retrievals of the phytoplankton absorption coefficient (aΦ) from space. As NPP is the efficiency in which absorbed energy is converted into carbon biomass, aΦ measurements circumvents chlorophyll-based empirical approaches by permitting direct and accurate measurements of phytoplankton energy absorption. It has long been recognized, and perhaps underappreciated, that NPP and phytoplankton growth rates display muted variability when normalized to aΦ rather than chlorophyll. Here we present a novel absorption-based NPP model that parameterizes the underlying physiological mechanisms behind this muted variability, and apply this physiological model to the global ocean. Through a comparison against field data from the Hawaii and Bermuda Ocean Time Series, we demonstrate how this approach yields more accurate NPP measurements than other published NPP models. By normalizing NPP to satellite estimates of phytoplankton carbon biomass, this presentation also explores the seasonality of phytoplankton growth rates across several oceanic regions. Finally, we discuss how future advances in remote-sensing (e.g. hyperspectral satellites, LIDAR, autonomous profilers) can be exploited to further improve absorption-based NPP models.

Measurements and simulation of forest leaf area index and net primary productivity in Northern China.

PubMed

Wang, P; Sun, R; Hu, J; Zhu, Q; Zhou, Y; Li, L; Chen, J M

2007-11-01

Large scale process-based modeling is a useful approach to estimate distributions of global net primary productivity (NPP). In this paper, in order to validate an existing NPP model with observed data at site level, field experiments were conducted at three sites in northern China. One site is located in Qilian Mountain in Gansu Province, and the other two sites are in Changbaishan Natural Reserve and Dunhua County in Jilin Province. Detailed field experiments are discussed and field data are used to validate the simulated NPP. Remotely sensed images including Landsat Enhanced Thematic Mapper plus (ETM+, 30 m spatial resolution in visible and near infrared bands) and Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER, 15m spatial resolution in visible and near infrared bands) are used to derive maps of land cover, leaf area index, and biomass. Based on these maps, field measured data, soil texture and daily meteorological data, NPP of these sites are simulated for year 2001 with the boreal ecosystem productivity simulator (BEPS). The NPP in these sites ranges from 80 to 800 gCm(-2)a(-1). The observed NPP agrees well with the modeled NPP. This study suggests that BEPS can be used to estimate NPP in northern China if remotely sensed images of high spatial resolution are available.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pantelias, M.; Volmert, B.; Caruso, S.

MCNP models of all Swiss Nuclear Power Plants have been developed by the National Cooperative for the Disposal of Radioactive Waste (Nagra), in collaboration with the utilities and ETH Zurich, for the 2011 decommissioning cost study. The estimation of the residual radionuclide inventories and corresponding activity levels of irradiated structures and components following the NPP shut-down is of crucial importance for the planning of the dismantling process, the waste packaging concept and, consequently, for the estimation of the decommissioning costs. Based on NPP specific data, the neutron transport simulations lead to the best yet knowledge of the neutron spectra necessarymore » for the ensuing activation calculations. In this paper, the modeling concept towards the MCNP-NPPs is outlined and the resulting flux distribution maps are presented. (authors)« less

KSC-2011-6571

NASA Image and Video Library

2011-07-28

VANDENBERG AIR FORCE BASE, Calif. -- At Vandenberg Air Force Base in California, technicians monitor the progress as a solid rocket motor is attached to a United Launch Alliance Delta II rocket at NASA’s Space Launch Complex-2. The Delta II will carry NASA's National Polar-orbiting Operational Environmental Satellite System Preparatory Project (NPP) satellite. NPP represents a critical first step in building the next-generation of Earth-observing satellites. NPP will carry the first of the new sensors developed for this satellite fleet, now known as the Joint Polar Satellite System (JPSS) to be launched in 2016. NPP is the bridge between NASA's Earth Observing System (EOS) satellites and the forthcoming series of JPSS satellites. The mission will test key technologies and instruments for the JPSS missions. NPP is targeted to launch Oct. 25. For more information, visit http://www.nasa.gov/NPP. Photo credit: NASA/VAFB, Dan Liberotti

KSC-2011-7015

NASA Image and Video Library

2011-08-30

VANDENBERG AIR FORCE BASE, Calif. – In the Astrotech Payload Processing Facility at Vandenberg Air Force Base in California, technicians remove the lifting crane and harnesses from the container holding NASA’s National Polar-orbiting Operational Environmental Satellite System Preparatory Project (NPP). NPP represents a critical first step in building the next-generation of Earth-observing satellites. NPP will carry the first of the new sensors developed for this satellite fleet, now known as the Joint Polar Satellite System (JPSS), to be launched in 2016. NPP is the bridge between NASA’s Earth Observing System (EOS) satellites and the forthcoming series of JPSS satellites. The mission will test key technologies and instruments for the JPSS missions. NPP is targeted to launch Oct. 25 from Space Launch Complex-2 aboard a United Launch Alliance Delta II rocket. For more information, visit http://www.nasa.gov/NPP. Photo credit: NASA/30th Communications Squadron, VAFB

KSC-2011-7025

NASA Image and Video Library

2011-09-08

VANDENBERG AIR FORCE BASE, Calif. – In a clean room inside the Astrotech Payload Processing Facility at Vandenberg Air Force Base in California, Ball Aerospace technicians rotate NASA’s National Polar-orbiting Operational Environmental Satellite System Preparatory Project (NPP) into the vertical position during a solar array frangible bolt pre-load verification test. NPP represents a critical first step in building the next-generation of Earth-observing satellites. NPP will carry the first of the new sensors developed for this satellite fleet, now known as the Joint Polar Satellite System (JPSS), to be launched in 2016. NPP is the bridge between NASA’s Earth Observing System (EOS) satellites and the forthcoming series of JPSS satellites. The mission will test key technologies and instruments for the JPSS missions. NPP is targeted to launch Oct. 25 from Space Launch Complex-2 aboard a United Launch Alliance Delta II rocket. For more information, visit http://www.nasa.gov/NPP. Photo credit: NASA/30th Communications Squadron, VAFB

KSC-2011-7014

NASA Image and Video Library

2011-08-30

VANDENBERG AIR FORCE BASE, Calif. – In the Astrotech Payload Processing Facility at Vandenberg Air Force Base in California, technicians monitor the progress as a crane begins to lift the container holding NASA’s National Polar-orbiting Operational Environmental Satellite System Preparatory Project (NPP). NPP represents a critical first step in building the next-generation of Earth-observing satellites. NPP will carry the first of the new sensors dev eloped for this satellite fleet, now known as the Joint Polar Satellite System (JPSS), to be launched in 2016. NPP is the bridge between NASA’s Earth Observing System (EOS) satellites and the forthcoming series of JPSS satellites. The mission will test key technologies and instruments for the JPSS missions. NPP is targeted to launch Oct. 25 from Space Launch Complex-2 aboard a United Launch Alliance Delta II rocket. For more information, visit http://www.nasa.gov/NPP. Photo credit: NASA/30th Communications Squadron, VAFB

KSC-2011-7017

NASA Image and Video Library

2011-09-01

VANDENBERG AIR FORCE BASE, Calif. – NASA’s National Polar-orbiting Operational Environmental Satellite System Preparatory Project (NPP) is positioned on a test platform in a clean room inside the Astrotech Payload Processing Facility at Vandenberg Air Force Base in California. NPP represents a critical first step in building the next-generation of Earth-observing satellites. NPP will carry the first of the new sensors developed for this satellite fleet, now known as the Joint Polar Satellite System (JPSS), to be launched in 2016. NPP is the bridge between NASA’s Earth Observing System (EOS) satellites and the forthcoming series of JPSS satellites. The mission will test key technologies and instruments for the JPSS missions. NPP is targeted to launch Oct. 25 from Space Launch Complex-2 aboard a United Launch Alliance Delta II rocket. For more information, visit http://www.nasa.gov/NPP. Photo credit: NASA/30th Communications Squadron, VAFB

KSC-2011-7011

NASA Image and Video Library

2011-08-30

VANDENBERG AIR FORCE BASE, Calif. – In the Astrotech Payload Processing Facility at Vandenberg Air Force Base in California, technicians attach a crane to the container holding NASA’s National Polar-orbiting Operational Environmental Satellite System Preparatory Project (NPP). NPP represents a critical first step in building the next-generation of Earth-observing satellites. NPP will carry the first of the new sensors developed for this satellite fleet, now known as the Joint Polar Satellite System (JPSS), to be launched in 2016. NPP is the bridge between NASA’s Earth Observing System (EOS) satellites and the forthcoming series of JPSS satellites. The mission will test key technologies and instruments for the JPSS missions. NPP is targeted to launch Oct. 25 from Space Launch Complex-2 aboard a United Launch Alliance Delta II rocket. For more information, visit http://www.nasa.gov/NPP. Photo credit: NASA/30th Communications Squadron, VAFB

KSC-2011-7027

NASA Image and Video Library

2011-09-08

VANDENBERG AIR FORCE BASE, Calif. – In a clean room inside the Astrotech Payload Processing Facility at Vandenberg Air Force Base in California, Ball Aerospace technicians rotate NASA’s National Polar-orbiting Operational Environmental Satellite System Preparatory Project (NPP) into the vertical position during a solar array frangible bolt pre-load verification test. NPP represents a critical first step in building the next-generation of Earth-observing satellites. NPP will carry the first of the new sensors developed for this satellite fleet, now known as the Joint Polar Satellite System (JPSS), to be launched in 2016. NPP is the bridge between NASA’s Earth Observing System (EOS) satellites and the forthcoming series of JPSS satellites. The mission will test key technologies and instruments for the JPSS missions. NPP is targeted to launch Oct. 25 from Space Launch Complex-2 aboard a United Launch Alliance Delta II rocket. For more information, visit http://www.nasa.gov/NPP. Photo credit: NASA/30th Communications Squadron, VAFB

KSC-2011-7022

NASA Image and Video Library

2011-09-08

VANDENBERG AIR FORCE BASE, Calif. – In a clean room inside the Astrotech Payload Processing Facility at Vandenberg Air Force Base in California, Ball Aerospace technicians position NASA’s National Polar-orbiting Operational Environmental Satellite System Preparatory Project (NPP) for a solar array frangible bolt pre-load verification test. NPP represents a critical first step in building the next-generation of Earth-observing satellites. NPP will carry the first of the new sensors developed for this satellite fleet, now known as the Joint Polar Satellite System (JPSS), to be launched in 2016. NPP is the bridge between NASA’s Earth Observing System (EOS) satellites and the forthcoming series of JPSS satellites. The mission will test key technologies and instruments for the JPSS missions. NPP is targeted to launch Oct. 25 from Space Launch Complex-2 aboard a United Launch Alliance Delta II rocket. For more information, visit http://www.nasa.gov/NPP. Photo credit: NASA/30th Communications Squadron, VAFB

KSC-2011-7023

NASA Image and Video Library

2011-09-08

VANDENBERG AIR FORCE BASE, Calif. – NASA’s National Polar-orbiting Operational Environmental Satellite System Preparatory Project (NPP) is positioned on a test platform in a clean room inside the Astrotech Payload Processing Facility at Vandenberg Air Force Base in California, awaiting a solar array frangible bolt pre-load verification test. NPP represents a critical first step in building the next-generation of Earth-observing satellites. NPP will carry the first of the new sensors developed for this satellite fleet, now known as the Joint Polar Satellite System (JPSS), to be launched in 2016. NPP is the bridge between NASA’s Earth Observing System (EOS) satellites and the forthcoming series of JPSS satellites. The mission will test key technologies and instruments for the JPSS missions. NPP is targeted to launch Oct. 25 from Space Launch Complex-2 aboard a United Launch Alliance Delta II rocket. For more information, visit http://www.nasa.gov/NPP. Photo credit: NASA/30th Communications Squadron, VAFB

KSC-2011-7026

NASA Image and Video Library

2011-09-08

VANDENBERG AIR FORCE BASE, Calif. – In a clean room inside the Astrotech Payload Processing Facility at Vandenberg Air Force Base in California, Ball Aerospace technicians rotate NASA’s National Polar-orbiting Operational Environmental Satellite System Preparatory Project (NPP) into the vertical position during a solar array frangible bolt pre-load verification test. NPP represents a critical first step in building the next-generation of Earth-observing satellites. NPP will carry the first of the new sensors developed for this satellite fleet, now known as the Joint Polar Satellite System (JPSS), to be launched in 2016. NPP is the bridge between NASA’s Earth Observing System (EOS) satellites and the forthcoming series of JPSS satellites. The mission will test key technologies and instruments for the JPSS missions. NPP is targeted to launch Oct. 25 from Space Launch Complex-2 aboard a United Launch Alliance Delta II rocket. For more information, visit http://www.nasa.gov/NPP. Photo credit: NASA/30th Communications Squadron, VAFB

KSC-2011-7018

NASA Image and Video Library

2011-09-01

VANDENBERG AIR FORCE BASE, Calif. – In a clean room inside the Astrotech Payload Processing Facility at Vandenberg Air Force Base in California, technicians position NASA’s National Polar-orbiting Operational Environmental Satellite System Preparatory Project (NPP) for test and checkout. NPP represents a critical first step in building the next-generation of Earth-observing satellites. NPP will carry the first of the new sensors developed for this satellite fleet, now known as the Joint Polar Satellite System (JPSS), to be launched in 2016. NPP is the bridge between NASA’s Earth Observing System (EOS) satellites and the forthcoming series of JPSS satellites. The mission will test key technologies and instruments for the JPSS missions. NPP is targeted to launch Oct. 25 from Space Launch Complex-2 aboard a United Launch Alliance Delta II rocket. For more information, visit http://www.nasa.gov/NPP. Photo credit: NASA/30th Communications Squadron, VAFB

KSC-2011-7016

NASA Image and Video Library

2011-09-01

VANDENBERG AIR FORCE BASE, Calif. – In a clean room inside the Astrotech Payload Processing Facility at Vandenberg Air Force Base in California, technicians position NASA’s National Polar-orbiting Operational Environmental Satellite System Preparatory Project (NPP) for test and checkout. NPP represents a critical first step in building the next-generation of Earth-observing satellites. NPP will carry the first of the new sensors developed for this satellite fleet, now known as the Joint Polar Satellite System (JPSS), to be launched in 2016. NPP is the bridge between NASA’s Earth Observing System (EOS) satellites and the forthcoming series of JPSS satellites. The mission will test key technologies and instruments for the JPSS missions. NPP is targeted to launch Oct. 25 from Space Launch Complex-2 aboard a United Launch Alliance Delta II rocket. For more information, visit http://www.nasa.gov/NPP. Photo credit: NASA/30th Communications Squadron, VAFB

KSC-2011-6630

NASA Image and Video Library

2011-08-30

VANDENBERG AIR FORCE BASE, Calif. -- The environmentally controlled transportation container holding NASA's National Polar-orbiting Operational Environmental Satellite System Preparatory Project (NPP) satellite arrives outside the Astrotech payload processing facility on Vandenberg Air Force Base in California. NPP represents a critical first step in building the next-generation of Earth-observing satellites. NPP will carry the first of the new sensors developed for this satellite fleet, now known as the Joint Polar Satellite System (JPSS), to be launched in 2016. NPP is the bridge between NASA's Earth Observing System (EOS) satellites and the forthcoming series of JPSS satellites. The mission will test key technologies and instruments for the JPSS missions. NPP is targeted to launch Oct. 25 from Space Launch Complex-2 aboard a United Launch Alliance Delta II rocket. For more information, visit http://www.nasa.gov/NPP. Photo credit: USAF 30th Space Communications Squadron/Doug Gruben, VAFB

KSC-2011-7010

NASA Image and Video Library

2011-08-30

VANDENBERG AIR FORCE BASE, Calif. – In the Astrotech Payload Processing Facility at Vandenberg Air Force Base in California, technicians prepare to attach a crane to the container holding NASA’s National Polar-orbiting Operational Environmental Satellite System Preparatory Project (NPP). NPP represents a critical first step in building the next-generation of Earth-observing satellites. NPP will carry the first of the new sensors developed for this satellite fleet, now known as the Joint Polar Satellite System (JPSS), to be launched in 2016. NPP is the bridge between NASA’s Earth Observing System (EOS) satellites and the forthcoming series of JPSS satellites. The mission will test key technologies and instruments for the JPSS missions. NPP is targeted to launch Oct. 25 from Space Launch Complex-2 aboard a United Launch Alliance Delta II rocket. For more information, visit http://www.nasa.gov/NPP. Photo credit: NASA/30th Communications Squadron, VAFB

KSC-2011-7013

NASA Image and Video Library

2011-08-30

VANDENBERG AIR FORCE BASE, Calif. – In the Astrotech Payload Processing Facility at Vandenberg Air Force Base in California, technicians monitor the progress as a crane begins to lift the container holding NASA’s National Polar-orbiting Operational Environmental Satellite System Preparatory Project (NPP). NPP represents a critical first step in building the next-generation of Earth-observing satellites. NPP will carry the first of the new sensors developed for this satellite fleet, now known as the Joint Polar Satellite System (JPSS), to be launched in 2016. NPP is the bridge between NASA’s Earth Observing System (EOS) satellites and the forthcoming series of JPSS satellites. The mission will test key technologies and instruments for the JPSS missions. NPP is targeted to launch Oct. 25 from Space Launch Complex-2 aboard a United Launch Alliance Delta II rocket. For more information, visit http://www.nasa.gov/NPP. Photo credit: NASA/30th Communications Squadron, VAFB

KSC-2011-7024

NASA Image and Video Library

2011-09-08

VANDENBERG AIR FORCE BASE, Calif. – In a clean room inside the Astrotech Payload Processing Facility at Vandenberg Air Force Base in California, Ball Aerospace technicians position NASA’s National Polar-orbiting Operational Environmental Satellite System Preparatory Project (NPP) for a solar array frangible bolt pre-load verification test. NPP represents a critical first step in building the next-generation of Earth-observing satellites. NPP will carry the first of the new sensors developed for this satellite fleet, now known as the Joint Polar Satellite System (JPSS), to be launched in 2016. NPP is the bridge between NASA’s Earth Observing System (EOS) satellites and the forthcoming series of JPSS satellites. The mission will test key technologies and instruments for the JPSS missions. NPP is targeted to launch Oct. 25 from Space Launch Complex-2 aboard a United Launch Alliance Delta II rocket. For more information, visit http://www.nasa.gov/NPP. Photo credit: NASA/30th Communications Squadron, VAFB

KSC-2011-7504

NASA Image and Video Library

2011-10-04

The Dynamic Ionosphere Cubesat Experiment DICE is prepared for launch aboard the Delta II rocket that will carry NASA’s National Polar-orbiting Operational Environmental Satellite System Preparatory Project NPP spacecraft. DICE is a National Science Foundation Project conducted by Utah State University in conjunction with the Atmospheric and Space Technology Research Associates ASTRA. NPP represents a critical first step in building the next-generation of Earth-observing satellites. NPP will carry the first of the new sensors developed for this satellite fleet, now known as the Joint Polar Satellite System JPSS, to be launched in 2016. NPP is the bridge between NASA's Earth Observing System EOS satellites and the forthcoming series of JPSS satellites. The mission will test key technologies and instruments for the JPSS missions. NPP is targeted to launch Oct. 28 from Space Launch Complex-2 aboard a United Launch Alliance Delta II rocket. For more information, visit http://www.nasa.gov/NPP. Photo credit: NASA/VAFB

KSC-2011-6633

NASA Image and Video Library

2011-08-30

VANDENBERG AIR FORCE BASE, Calif. -- The environmentally controlled transportation container holding NASA's National Polar-orbiting Operational Environmental Satellite System Preparatory Project (NPP) satellite comes to rest on the floor of the Astrotech payload processing facility on Vandenberg Air Force Base in California. NPP represents a critical first step in building the next-generation of Earth-observing satellites. NPP will carry the first of the new sensors developed for this satellite fleet, now known as the Joint Polar Satellite System (JPSS), to be launched in 2016. NPP is the bridge between NASA's Earth Observing System (EOS) satellites and the forthcoming series of JPSS satellites. The mission will test key technologies and instruments for the JPSS missions. NPP is targeted to launch Oct. 25 from Space Launch Complex-2 aboard a United Launch Alliance Delta II rocket. For more information, visit http://www.nasa.gov/NPP. Photo credit: NASA/Jerry Nagy, VAFB

KSC-2011-7008

NASA Image and Video Library

2011-08-30

VANDENBERG AIR FORCE BASE, Calif. – Transported by truck, the environmentally controlled transportation container holding NASA’s National Polar-orbiting Operational Environmental Satellite System Preparatory Project (NPP) arrives at the Astrotech Payload Processing Facility at Vandenberg Air Force Base in California. NPP represents a critical first step in building the next-generation of Earth-observing satellites. NPP will carry the first of the new sensors developed for this satellite fleet, now known as the Joint Polar Satellite System (JPSS), to be launched in 2016. NPP is the bridge between NASA’s Earth Observing System (EOS) satellites and the forthcoming series of JPSS satellites. The mission will test key technologies and instruments for the JPSS missions. NPP is targeted to launch Oct. 25 from Space Launch Complex-2 aboard a United Launch Alliance Delta II rocket. For more information, visit http://www.nasa.gov/NPP. Photo credit: NASA/30th Communications Squadron, VAFB

KSC-2011-7007

NASA Image and Video Library

2011-08-30

VANDENBERG AIR FORCE BASE, Calif. – Transported by truck, the environmentally controlled transportation container holding NASA’s National Polar-orbiting Operational Environmental Satellite System Preparatory Project (NPP) arrives at the Astrotech Payload Processing Facility at Vandenberg Air Force Base in California. NPP represents a critical first step in building the next-generation of Earth-observing satellites. NPP will carry the first of the new sensors developed for this satellite fleet, now known as the Joint Polar Satellite System (JPSS), to be launched in 2016. NPP is the bridge between NASA’s Earth Observing System (EOS) satellites and the forthcoming series of JPSS satellites. The mission will test key technologies and instruments for the JPSS missions. NPP is targeted to launch Oct. 25 from Space Launch Complex-2 aboard a United Launch Alliance Delta II rocket. For more information, visit http://www.nasa.gov/NPP. Photo credit: NASA/30th Communications Squadron, VAFB

KSC-2011-6631

NASA Image and Video Library

2011-08-30

VANDENBERG AIR FORCE BASE, Calif. -- The environmentally controlled transportation container holding NASA's National Polar-orbiting Operational Environmental Satellite System Preparatory Project (NPP) satellite is delivered into the Astrotech payload processing facility on Vandenberg Air Force Base in California. NPP represents a critical first step in building the next-generation of Earth-observing satellites. NPP will carry the first of the new sensors developed for this satellite fleet, now known as the Joint Polar Satellite System (JPSS), to be launched in 2016. NPP is the bridge between NASA's Earth Observing System (EOS) satellites and the forthcoming series of JPSS satellites. The mission will test key technologies and instruments for the JPSS missions. NPP is targeted to launch Oct. 25 from Space Launch Complex-2 aboard a United Launch Alliance Delta II rocket. For more information, visit http://www.nasa.gov/NPP. Photo credit: USAF 30th Space Communications Squadron/Doug Gruben, VAFB

KSC-2011-6632

NASA Image and Video Library

2011-08-30

VANDENBERG AIR FORCE BASE, Calif. -- The environmentally controlled transportation container holding NASA's National Polar-orbiting Operational Environmental Satellite System Preparatory Project (NPP) satellite is lifted from its delivery truck at the Astrotech payload processing facility on Vandenberg Air Force Base in California. NPP represents a critical first step in building the next-generation of Earth-observing satellites. NPP will carry the first of the new sensors developed for this satellite fleet, now known as the Joint Polar Satellite System (JPSS), to be launched in 2016. NPP is the bridge between NASA's Earth Observing System (EOS) satellites and the forthcoming series of JPSS satellites. The mission will test key technologies and instruments for the JPSS missions. NPP is targeted to launch Oct. 25 from Space Launch Complex-2 aboard a United Launch Alliance Delta II rocket. For more information, visit http://www.nasa.gov/NPP. Photo credit: NASA/Jerry Nagy, VAFB

KSC-2011-7005

NASA Image and Video Library

2011-08-30

VANDENBERG AIR FORCE BASE, Calif. – The Astrotech Payload Processing Facility at Vandenberg Air Force Base in California awaits delivery of the environmentally controlled transportation container holding NASA’s National Polar-orbiting Operational Environmental Satellite System Preparatory Project (NPP). NPP represents a critical first step in building the next-generation of Earth-observing satellites. NPP will carry the first of the new sensors developed for this satellite fleet, now known as the Joint Polar Satellite System (JPSS), to be launched in 2016. NPP is the bridge between NASA’s Earth Observing System (EOS) satellites and the forthcoming series of JPSS satellites. The mission will test key technologies and instruments for the JPSS missions. NPP is targeted to launch Oct. 25 from Space Launch Complex-2 aboard a United Launch Alliance Delta II rocket. For more information, visit http://www.nasa.gov/NPP. Photo credit: NASA/30th Communications Squadron, VAFB

KSC-2011-7006

NASA Image and Video Library

2011-08-30

VANDENBERG AIR FORCE BASE, Calif. – Transported by truck, the environmentally controlled transportation container holding NASA’s National Polar-orbiting Operational Environmental Satellite System Preparatory Project (NPP) arrives at the Astrotech Payload Processing Facility at Vandenberg Air Force Base in California. NPP represents a critical first step in building the next-generation of Earth-observing satellites. NPP will carry the first of the new sensors developed for this satellite fleet, now known as the Joint Polar Satellite System (JPSS), to be launched in 2016. NPP is the bridge between NASA’s Earth Observing System (EOS) satellites and the forthcoming series of JPSS satellites. The mission will test key technologies and instruments for the JPSS missions. NPP is targeted to launch Oct. 25 from Space Launch Complex-2 aboard a United Launch Alliance Delta II rocket. For more information, visit http://www.nasa.gov/NPP. Photo credit: NASA/30th Communications Squadron, VAFB

KSC-2011-7550

NASA Image and Video Library

2011-10-26

VANDENBERG AIR FORCE BASE, Calif. -- Participants in the prelaunch news conference at Vandenberg Air Force Base, Calif., for NASA’s National Polar-orbiting Operational Environmental Satellite System Preparatory Project (NPP) spacecraft prepare to address members of the news media gathered at Vandenberg Air Force Base, Calif. NPP represents a critical first step in building the next-generation of Earth-observing satellites. NPP will carry the first of the new sensors developed for this satellite fleet, now known as the Joint Polar Satellite System (JPSS), to be launched in 2016. NPP is the bridge between NASA's Earth Observing System (EOS) satellites and the forthcoming series of JPSS satellites. The mission will test key technologies and instruments for the JPSS missions. NPP is targeted to launch Oct. 28 from Space Launch Complex-2 aboard a United Launch Alliance Delta II rocket. For more information, visit http://www.nasa.gov/NPP. Photo credit: NASA/VAFB

KSC-2011-7009

NASA Image and Video Library

2011-08-30

VANDENBERG AIR FORCE BASE, Calif. – Transported by truck, the environmentally controlled transportation container holding NASA’s National Polar-orbiting Operational Environmental Satellite System Preparatory Project (NPP) arrives at the Astrotech Payload Processing Facility at Vandenberg Air Force Base in California. NPP represents a critical first step in building the next-generation of Earth-observing satellites. NPP will carry the first of the new sensors developed for this satellite fleet, now known as the Joint Polar Satellite System (JPSS), to be launched in 2016. NPP is the bridge between NASA’s Earth Observing System (EOS) satellites and the forthcoming series of JPSS satellites. The mission will test key technologies and instruments for the JPSS missions. NPP is targeted to launch Oct. 25 from Space Launch Complex-2 aboard a United Launch Alliance Delta II rocket. For more information, visit http://www.nasa.gov/NPP. Photo credit: NASA/30th Communications Squadron, VAFB

KSC-2011-7549

NASA Image and Video Library

2011-10-26

VANDENBERG AIR FORCE BASE, Calif. -- Vernon Thorp, program manager, NASA missions, United Launch Alliance, Cape Canaveral, Fla., participates in the prelaunch news conference at Vandenberg Air Force Base, Calif., for NASA’s National Polar-orbiting Operational Environmental Satellite System Preparatory Project (NPP) spacecraft. NPP represents a critical first step in building the next-generation of Earth-observing satellites. NPP will carry the first of the new sensors developed for this satellite fleet, now known as the Joint Polar Satellite System (JPSS), to be launched in 2016. NPP is the bridge between NASA's Earth Observing System (EOS) satellites and the forthcoming series of JPSS satellites. The mission will test key technologies and instruments for the JPSS missions. NPP is targeted to launch Oct. 28 from Space Launch Complex-2 aboard a United Launch Alliance Delta II rocket. For more information, visit http://www.nasa.gov/NPP. Photo credit: NASA/VAFB

Modeling the spatial-temporal dynamics of net primary production in Yangtze River Basin using IBIS model

USGS Publications Warehouse

Zhang, Z.; Jiang, H.; Liu, J.; Zhu, Q.; Wei, X.; Jiang, Z.; Zhou, G.; Zhang, X.; Han, J.

2011-01-01

The climate change has significantly affected the carbon cycling in Yangtze River Basin. To better understand the alternation pattern for the relationship between carbon cycling and climate change, the net primary production (NPP) were simulated in the study area from 1956 to 2006 by using the Integrated Biosphere Simulator (IBIS). The results showed that the average annual NPP per square meter was about 0.518 kg C in Yangtze River Basin. The high NPP levels were mainly distributed in the southeast area of Sichuan, and the highest value reached 1.05 kg C/m2. The NPP increased based on the simulated temporal trends. The spatiotemporal variability of the NPP in the vegetation types was obvious, and it was depended on the climate and soil condition. We found the drought climate was one of critical factor that impacts the alterations of the NPP in the area by the simulation. ?? 2011 IEEE.

KSC-2011-7012

NASA Image and Video Library

2011-08-30

VANDENBERG AIR FORCE BASE, Calif. – In the Astrotech Payload Processing Facility at Vandenberg Air Force Base in California, technicians monitor the progress as a crane begins to lift the container holding NASA’s National Polar-orbiting Operational Environmental Satellite System Preparatory Project (NPP). NPP represents a critical first step in building the next-generation of Earth-observing satellites. NPP will carry the first of the new sensors developed for this satellite fleet, now known as the Joint Polar Satellite System (JPSS), to be launched in 2016. NPP is the bridge between NASA’s Earth Observing System (EOS) satellites and the forthcoming series of JPSS satellites. The mission will test key technologies and instruments for the JPSS missions. NPP is targeted to launch Oct. 25 from Space Launch Complex-2 aboard a United Launch Alliance Delta II rocket. For more information, visit http://www.nasa.gov/NPP. Photo credit: NASA/30th Communications Squadron, VAFB

KSC-2011-7543

NASA Image and Video Library

2011-10-26

VANDENBERG AIR FORCE BASE, Calif. -- A model of the NASA’s National Polar-orbiting Operational Environmental Satellite System Preparatory Project (NPP) spacecraft and the United Launch Alliance Delta II rocket are displayed during the prelaunch news conference at Vandenberg Air Force Base, Calif. NPP represents a critical first step in building the next-generation of Earth-observing satellites. NPP will carry the first of the new sensors developed for this satellite fleet, now known as the Joint Polar Satellite System (JPSS), to be launched in 2016. NPP is the bridge between NASA's Earth Observing System (EOS) satellites and the forthcoming series of JPSS satellites. The mission will test key technologies and instruments for the JPSS missions. NPP is targeted to launch Oct. 28 from Space Launch Complex-2 aboard a United Launch Alliance Delta II rocket. For more information, visit http://www.nasa.gov/NPP. Photo credit: NASA/VAFB

Spatial and temporal patterns of net primary productivity in the duration of 1981-2000 in Guangdong, China

USGS Publications Warehouse

Liu, Hai-Gui; Tang, Xu-Li; Zhou, Guo-Yi; Liu, Shu-Guang

2007-01-01

The knowledge of net primary production (NPP) dynamics at regional scale will help to understand terrestrial carbon cycling, especially with respect to land use and global climate change. Guangdong province has high plant growth potential because of plenty of light, heat, and water resources in this region. Forest coverage increased significantly from less than 30% in the early l980s to approximately 60% in 2000 owing to the launching of the "Greening Guangdong in 10 years", a provincial afforestation and reforestation project started in 1985. Meanwhile, economy growth has been fast in Guangdong province during the past 20 years. Long-term spatial and temporal NPP dynamics in Guangdong province are not well-known. To fill this knowledge gap, the spatial and temporal patterns of annual NPP from 1981 to 2000, derived from the global production efficiency model (GLO-PEM), were analyzed in this study. NPP patterns were compared at three spatial scales (i. e. , province, region, and city) and among three major forest types (i. e. , broadleaf, coniferous, and mixed). The results showed that for the entire province annual NPP varied between (1360 ±431) and (1626 ± 471) g/(m^2•a), with a mean value of (1480 ±407)g/(m^2•a). NPP increased to the maximum value (1534 ±121 g/(m^2•a)) in late 1980s (1986~1990) while decreased in early 1990s (1991~1995), and then recovered slightly in late 1990s (1996~2000). NPP differed distinctly across geographic regions, with the highest in the southwest coastal region, followed by the southeast coastal region, and the lowest in the inner land region. The differences were probably caused by vegetation composition, heat and water resources, and the distribution of the cropland. NPP dynamics of 21 cities were divided into three types. NPP kept stable in 12 cities including Shaoguan, Qingyuan, and Meizhou etc. NPP increased in Chaozhou, Shanwei, Zhanjiang and Jieyang, and decreased significantly (p<0.05) in 5 cities (i. e. , Foshan, Zhongshan, Shenzhen, Dongguan and Zhuhai). The decrease of NPP in these 5 cites can partly be explained by land cover and land use changes (e. g. , urbanization) driven by the economy development in the Pearl River Delta. NPP varied among the three major forest types. The mixed forest had the highest NPP, followed by the broadleaf forest and the conifer forest. Long-term mean NPP were (1364 ± 390) g/(m^2•a), (1391 ± 372) g/(m^2•a), and (1704 ± 450) g/(m^2•a) in the conifer, the broadleaf, and the mixed forest, respectively.

A new approach to evaluate the MODIS annual NPP product (MOD17A3) using forest field data from Turkey

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gulbeyaz, Onder; Bond-Lamberty, Ben; Akyurek, Zuhal

In this study we present the first evaluation of the MODIS (MODerate resolution Imaging Spectroradiometer) annual Net Primary Product (NPP) for Turkey's forest ecosystems using field measurements. Due to lack of country scale field measurements (i.e. flux tower for forest ecosystems), tree DBH (Diameter at Breast Height) dataset provided by Ministry of Forest and Water Affair (MFWA) of Turkey is used to calculate NPP of Turkey’s forest ecosystems. The lack of a reliable NPP dataset leads the researchers to use global NPP models such as MODIS annual NPP product. The MODIS MOD17A3 product of vegetation net primary production (NPP) ismore » one of the most highly used data sources for studies of global carbon 25 cycle. However, it is still necessary to test its predictions in multiple biomes, especially for heterogeneous areas in terms of its accuracy and potential bias. Here, we studied a new approach to evaluate coarse scale NPP estimates from the MODIS NPP- MOD17A3 data product, using 2008-2013 field measurements of tree growth throughout Turkey. There different methods were used to calculate field NPP, including standardized growth coefficients (MC), growth coefficients from North America (JC) and annual expected increment (AEI). The average NPP values for all the country is calculated as 2.06 kgC m-2(5years)-1 (0.412 kgC m-2 year-1) (SD = 1.15 kgC m-2 (5years)-1) from MOD17A3, 0.90 kgC m-2(5years)-1 (0.18 kgC m-2 year-1) (SD = 0.57 kgC m-2(5years)-1) with MC, 0.63 kgC m-2(5years)-1 (0.126 kgC m-2 year-1) (SD = 0.37 kgC m-2(5years)-1) with JC and 0.58 kgC m-2 year-1 (SD = 0.29 kgC m-2(5years)-1) with AEI for the studied plots. We found that the MODIS NPP product has a clear relation with both the NPP estimates obtained by using MC (R36 2 = 0.34, RMSE=1.51 kgC m-2(5years)-1) and JC (R37 2 = 0.32, RMSE = 1.73 kgC m-2(5years)-1). In addition to that, the relation between MOD17A3 product and AEI-derived NPP is relatively strong (R39 2 = 0.48, RMSE = 0.26 kgC m-2 year-1). We discuss possible reasons for these trade-offs among different methods. This study lays out a new approach to validate coarse scale MODIS product using field data directly, including for highly heterogeneous areas.« less

Modeled responses of terrestrial ecosystems to elevated atmospheric CO2: a comparison of simulations by the biogeochemistry models of the Vegetation/Ecosystem Modeling and Analysis Project (VEMAP).

PubMed

Pan, Yude; Melillo, Jerry M; McGuire, A David; Kicklighter, David W; Pitelka, Louis F; Hibbard, Kathy; Pierce, Lars L; Running, Steven W; Ojima, Dennis S; Parton, William J; Schimel, David S

1998-04-01

Although there is a great deal of information concerning responses to increases in atmospheric CO 2 at the tissue and plant levels, there are substantially fewer studies that have investigated ecosystem-level responses in the context of integrated carbon, water, and nutrient cycles. Because our understanding of ecosystem responses to elevated CO 2 is incomplete, modeling is a tool that can be used to investigate the role of plant and soil interactions in the response of terrestrial ecosystems to elevated CO 2 . In this study, we analyze the responses of net primary production (NPP) to doubled CO 2 from 355 to 710 ppmv among three biogeochemistry models in the Vegetation/Ecosystem Modeling and Analysis Project (VEMAP): BIOME-BGC (BioGeochemical Cycles), Century, and the Terrestrial Ecosystem Model (TEM). For the conterminous United States, doubled atmospheric CO 2 causes NPP to increase by 5% in Century, 8% in TEM, and 11% in BIOME-BGC. Multiple regression analyses between the NPP response to doubled CO 2 and the mean annual temperature and annual precipitation of biomes or grid cells indicate that there are negative relationships between precipitation and the response of NPP to doubled CO 2 for all three models. In contrast, there are different relationships between temperature and the response of NPP to doubled CO 2 for the three models: there is a negative relationship in the responses of BIOME-BGC, no relationship in the responses of Century, and a positive relationship in the responses of TEM. In BIOME-BGC, the NPP response to doubled CO 2 is controlled by the change in transpiration associated with reduced leaf conductance to water vapor. This change affects soil water, then leaf area development and, finally, NPP. In Century, the response of NPP to doubled CO 2 is controlled by changes in decomposition rates associated with increased soil moisture that results from reduced evapotranspiration. This change affects nitrogen availability for plants, which influences NPP. In TEM, the NPP response to doubled CO 2 is controlled by increased carboxylation which is modified by canopy conductance and the degree to which nitrogen constraints cause down-regulation of photosynthesis. The implementation of these different mechanisms has consequences for the spatial pattern of NPP responses, and represents, in part, conceptual uncertainty about controls over NPP responses. Progress in reducing these uncertainties requires research focused at the ecosystem level to understand how interactions between the carbon, nitrogen, and water cycles influence the response of NPP to elevated atmospheric CO 2 .

Modeled responses of terrestrial ecosystems to elevated atmospheric CO2: A comparison of simulations by the biogeochemistry models of the Vegetation/Ecosystem Modeling and Analysis Project (VEMAP)

USGS Publications Warehouse

Pan, Y.; Melillo, J.M.; McGuire, A.D.; Kicklighter, D.W.; Pitelka, Louis F.; Hibbard, K.; Pierce, L.L.; Running, S.W.; Ojima, D.S.; Parton, W.J.; Schimel, D.S.; Borchers, J.; Neilson, R.; Fisher, H.H.; Kittel, T.G.F.; Rossenbloom, N.A.; Fox, S.; Haxeltine, A.; Prentice, I.C.; Sitch, S.; Janetos, A.; McKeown, R.; Nemani, R.; Painter, T.; Rizzo, B.; Smith, T.; Woodward, F.I.

1998-01-01

Although there is a great deal of information concerning responses to increases in atmospheric CO2 at the tissue and plant levels, there are substantially fewer studies that have investigated ecosystem-level responses in the context of integrated carbon, water, and nutrient cycles. Because our understanding of ecosystem responses to elevated CO2 is incomplete, modeling is a tool that can be used to investigate the role of plant and soil interactions in the response of terrestrial ecosystems to elevated CO2. In this study, we analyze the responses of net primary production (NPP) to doubled CO2 from 355 to 710 ppmv among three biogeochemistry models in the Vegetation/Ecosystem Modeling and Analysis Project (VEMAP): BIOME-BGC (BioGeochemical Cycles), Century, and the Terrestrial Ecosystem Model (TEM). For the conterminous United States, doubled atmospheric CO2 causes NPP to increase by 5% in Century, 8% in TEM, and 11% in BIOME-BGC. Multiple regression analyses between the NPP response to doubled CO2 and the mean annual temperature and annual precipitation of biomes or grid cells indicate that there are negative relationships between precipitation and the response of NPP to doubled CO2 for all three models. In contrast, there are different relationships between temperature and the response of NPP to doubled CO2 for the three models: there is a negative relationship in the responses of BIOME-BGC, no relationship in the responses of Century, and a positive relationship in the responses of TEM. In BIOME-BGC, the NPP response to doubled CO2 is controlled by the change in transpiration associated with reduced leaf conductance to water vapor. This change affects soil water, then leaf area development and, finally, NPP. In Century, the response of NPP to doubled CO2 is controlled by changes in decomposition rates associated with increased soil moisture that results from reduced evapotranspiration. This change affects nitrogen availability for plants, which influences NPP. In TEM, the NPP response to doubled CO2 is controlled by increased carboxylation which is modified by canopy conductance and the degree to which nitrogen constraints cause down-regulation of photosynthesis. The implementation of these different mechanisms has consequences for the spatial pattern of NPP responses, and represents, in part, conceptual uncertainty about controls over NPP responses. Progress in reducing these uncertainties requires research focused at the ecosystem level to understand how interactions between the carbon, nitrogen, and water cycles influence the response of NPP to elevated atmospheric CO2.

Psychosocial state of the adult evacuees and risk factors of negative change.

PubMed

Buzunov, V O; Loganovsky, K M; Krasnikova, L I; Bomko, M O; Belyayev, Yu M; Yaroshenko, Zh S; Domashevska, T E

2017-12-01

Numerous scientific studies have been carried out since the ChNPP accident indicating that the last one has caused a severe psychosocial stress in survivors. Population of radioactively contaminated territories, people migrated from the areas of strict radiation control, and accident consequences clean up participants in 1986 1987 were covered by the conducted research projects. Nature of the stress herewith is polygenic and includes factors directly related to the Chernobyl catastrophe, and factors being a result of social and economic circumstances. This report is devot ed to the results of research on psychosocial state of population evacuated from the 30 km zone of the ChNPP. Study and evaluation of psychosocial state of population evacuated from the 30 km ChNPP zone at the age of 18 years and older; identification of potential psychosocial risk factors for the health loss. The sampling epidemiological study of psychosocial state of population aged 18-50 years evacuated from the 30 km zone of ChNPP was conducted at the NRCRM Radiation Registry Outpatient Clinic and Radiation Psychoneurology Department. The study subjects (n=258) were mostly (98%) females. Study was con ducted from October 2013 till May 2015. All the sample members were registered since 1992 in the system of life long health monitoring, i.e. the NRCRM Clinical and Epidemiological Registry. Study subjects were interviewed through the method using an original «Questioning Inventory». Mathematical processing of study results was held using the Epi Info 7 software package. According to the study results, a nuclear accident at the Chornobyl NPP has become a powerful psychoso cial stress for evacuated people. Psychosocial state of the evacuees, formed during the post accident period, with full reason can be defined as a state of stable, chronic psychosocial stress. Nature of factors that caused the stress development is polygenic. Block of stressors directly related to the accident was determined, namely there were «change of radiation and ecological situation», «ionizing irradiation», «evacuation», and «radical breaking of dynamic stereotype of behavior and life». In parallel there was selected a block of stress factors generated by that background, i.e. psychological, social, economic, and cultural, on which a nuclear disaster was imposed upon. The effects of stress have manifested as a persistent syndrome of «anxiety» for the personal health and health of fami ly members, primarily the children, and as a stable state of «dissatisfaction» with fullness and quality of life. The nuclear accident at the ChNPP has been the cause of a strong psychosocial stress in adult evacu ated population, especially in women. Further in a remote period the stress was transformed into a stable, chronic form. Nature of stress is polygenic and includes stressors directly related to the accident, and stressors that are not directly related to the accident consequences, but are due to the level of social, economic, medical, and informa tional protection of survivors. Data presented in the paper are rather enough important for the formation of strate gies and measures for social and psychological protection of population in an event of nuclear accidents and incidents. V. O. Buzunov, K. M. Loganovsky, L. I. Krasnikova, M. O. Bomko, Yu. M. Belyayev, Zh. S. Yaroshenko, T. E. Domashevska.

Proteoliposomes harboring alkaline phosphatase and nucleotide pyrophosphatase as matrix vesicle biomimetics.

PubMed

Simão, Ana Maria S; Yadav, Manisha C; Narisawa, Sonoko; Bolean, Mayte; Pizauro, Joao Martins; Hoylaerts, Marc F; Ciancaglini, Pietro; Millán, José Luis

2010-03-05

We have established a proteoliposome system as an osteoblast-derived matrix vesicle (MV) biomimetic to facilitate the study of the interplay of tissue-nonspecific alkaline phosphatase (TNAP) and NPP1 (nucleotide pyrophosphatase/phosphodiesterase-1) during catalysis of biomineralization substrates. First, we studied the incorporation of TNAP into liposomes of various lipid compositions (i.e. in pure dipalmitoyl phosphatidylcholine (DPPC), DPPC/dipalmitoyl phosphatidylserine (9:1 and 8:2), and DPPC/dioctadecyl-dimethylammonium bromide (9:1 and 8:2) mixtures. TNAP reconstitution proved virtually complete in DPPC liposomes. Next, proteoliposomes containing either recombinant TNAP, recombinant NPP1, or both together were reconstituted in DPPC, and the hydrolysis of ATP, ADP, AMP, pyridoxal-5'-phosphate (PLP), p-nitrophenyl phosphate, p-nitrophenylthymidine 5'-monophosphate, and PP(i) by these proteoliposomes was studied at physiological pH. p-Nitrophenylthymidine 5'-monophosphate and PLP were exclusively hydrolyzed by NPP1-containing and TNAP-containing proteoliposomes, respectively. In contrast, ATP, ADP, AMP, PLP, p-nitrophenyl phosphate, and PP(i) were hydrolyzed by TNAP-, NPP1-, and TNAP plus NPP1-containing proteoliposomes. NPP1 plus TNAP additively hydrolyzed ATP, but TNAP appeared more active in AMP formation than NPP1. Hydrolysis of PP(i) by TNAP-, and TNAP plus NPP1-containing proteoliposomes occurred with catalytic efficiencies and mild cooperativity, effects comparable with those manifested by murine osteoblast-derived MVs. The reconstitution of TNAP and NPP1 into proteoliposome membranes generates a phospholipid microenvironment that allows the kinetic study of phosphosubstrate catabolism in a manner that recapitulates the native MV microenvironment.

Proteoliposomes Harboring Alkaline Phosphatase and Nucleotide Pyrophosphatase as Matrix Vesicle Biomimetics*

PubMed Central

Simão, Ana Maria S.; Yadav, Manisha C.; Narisawa, Sonoko; Bolean, Mayte; Pizauro, Joao Martins; Hoylaerts, Marc F.; Ciancaglini, Pietro; Millán, José Luis

2010-01-01

We have established a proteoliposome system as an osteoblast-derived matrix vesicle (MV) biomimetic to facilitate the study of the interplay of tissue-nonspecific alkaline phosphatase (TNAP) and NPP1 (nucleotide pyrophosphatase/phosphodiesterase-1) during catalysis of biomineralization substrates. First, we studied the incorporation of TNAP into liposomes of various lipid compositions (i.e. in pure dipalmitoyl phosphatidylcholine (DPPC), DPPC/dipalmitoyl phosphatidylserine (9:1 and 8:2), and DPPC/dioctadecyl-dimethylammonium bromide (9:1 and 8:2) mixtures. TNAP reconstitution proved virtually complete in DPPC liposomes. Next, proteoliposomes containing either recombinant TNAP, recombinant NPP1, or both together were reconstituted in DPPC, and the hydrolysis of ATP, ADP, AMP, pyridoxal-5′-phosphate (PLP), p-nitrophenyl phosphate, p-nitrophenylthymidine 5′-monophosphate, and PPi by these proteoliposomes was studied at physiological pH. p-Nitrophenylthymidine 5′-monophosphate and PLP were exclusively hydrolyzed by NPP1-containing and TNAP-containing proteoliposomes, respectively. In contrast, ATP, ADP, AMP, PLP, p-nitrophenyl phosphate, and PPi were hydrolyzed by TNAP-, NPP1-, and TNAP plus NPP1-containing proteoliposomes. NPP1 plus TNAP additively hydrolyzed ATP, but TNAP appeared more active in AMP formation than NPP1. Hydrolysis of PPi by TNAP-, and TNAP plus NPP1-containing proteoliposomes occurred with catalytic efficiencies and mild cooperativity, effects comparable with those manifested by murine osteoblast-derived MVs. The reconstitution of TNAP and NPP1 into proteoliposome membranes generates a phospholipid microenvironment that allows the kinetic study of phosphosubstrate catabolism in a manner that recapitulates the native MV microenvironment. PMID:20048161

An assessment of phytoplankton primary productivity in the Arctic Ocean from satellite ocean color/in situ chlorophyll‐a based models

PubMed Central

Matrai, Patricia A.; Friedrichs, Marjorie A. M.; Saba, Vincent S.; Antoine, David; Ardyna, Mathieu; Asanuma, Ichio; Babin, Marcel; Bélanger, Simon; Benoît‐Gagné, Maxime; Devred, Emmanuel; Fernández‐Méndez, Mar; Gentili, Bernard; Hirawake, Toru; Kang, Sung‐Ho; Kameda, Takahiko; Katlein, Christian; Lee, Sang H.; Lee, Zhongping; Mélin, Frédéric; Scardi, Michele; Smyth, Tim J.; Tang, Shilin; Turpie, Kevin R.; Waters, Kirk J.; Westberry, Toby K.

2015-01-01

Abstract We investigated 32 net primary productivity (NPP) models by assessing skills to reproduce integrated NPP in the Arctic Ocean. The models were provided with two sources each of surface chlorophyll‐a concentration (chlorophyll), photosynthetically available radiation (PAR), sea surface temperature (SST), and mixed‐layer depth (MLD). The models were most sensitive to uncertainties in surface chlorophyll, generally performing better with in situ chlorophyll than with satellite‐derived values. They were much less sensitive to uncertainties in PAR, SST, and MLD, possibly due to relatively narrow ranges of input data and/or relatively little difference between input data sources. Regardless of type or complexity, most of the models were not able to fully reproduce the variability of in situ NPP, whereas some of them exhibited almost no bias (i.e., reproduced the mean of in situ NPP). The models performed relatively well in low‐productivity seasons as well as in sea ice‐covered/deep‐water regions. Depth‐resolved models correlated more with in situ NPP than other model types, but had a greater tendency to overestimate mean NPP whereas absorption‐based models exhibited the lowest bias associated with weaker correlation. The models performed better when a subsurface chlorophyll‐a maximum (SCM) was absent. As a group, the models overestimated mean NPP, however this was partly offset by some models underestimating NPP when a SCM was present. Our study suggests that NPP models need to be carefully tuned for the Arctic Ocean because most of the models performing relatively well were those that used Arctic‐relevant parameters. PMID:27668139

Net primary productivity and rain-use efficiency as affected by warming, altered precipitation, and clipping in a mixed-grass prairie.

PubMed

Xu, Xia; Sherry, Rebecca A; Niu, Shuli; Li, Dejun; Luo, Yiqi

2013-09-01

Grassland productivity in response to climate change and land use is a global concern. In order to explore the effects of climate change and land use on net primary productivity (NPP), NPP partitioning [fBNPP , defined as the fraction of belowground NPP (BNPP) to NPP], and rain-use efficiency (RUE) of NPP, we conducted a field experiment with warming (+3 °C), altered precipitation (double and half), and annual clipping in a mixed-grass prairie in Oklahoma, USA since July, 2009. Across the years, warming significantly increased BNPP, fBNPP , and RUEBNPP by an average of 11.6%, 2.8%, and 6.6%, respectively. This indicates that BNPP was more sensitive to warming than aboveground NPP (ANPP) since warming did not change ANPP and RUEANPP much. Double precipitation stimulated ANPP, BNPP, and NPP but suppressed RUEANPP , RUEBNPP , and RUENPP while half precipitation decreased ANPP, BNPP, and NPP but increased RUEANPP , RUEBNPP , and RUENPP . Clipping interacted with altered precipitation in impacting RUEANPP , RUEBNPP , and RUENPP , suggesting land use could confound the effects of precipitation changes on ecosystem processes. Soil moisture was found to be a main factor in regulating variation in ANPP, BNPP, and NPP while soil temperature was the dominant factor influencing fBNPP . These findings suggest that BNPP is critical point to future research. Additionally, results from single-factor manipulative experiments should be treated with caution due to the non-additive interactive effects of warming with altered precipitation and land use (clipping). © 2013 John Wiley & Sons Ltd.

Assessment of NPP VIIRS Ocean Color Data Products: Hope and Risk

NASA Technical Reports Server (NTRS)

Turpie, Kevin R.; Meister, Gerhard; Eplee, Gene; Barnes, Robert A.; Franz, Bryan; Patt, Frederick S.; Robinson, Wayne d.; McClain, Charles R.

2010-01-01

For several years, the NASA/Goddard Space Flight Center (GSFC) NPP VIIRS Ocean Science Team (VOST) provided substantial scientific input to the NPP project regarding the use of Visible Infrared Imaging Radiometer Suite (VIIRS) to create science quality ocean color data products. This work has culminated into an assessment of the NPP project and the VIIRS instrument's capability to produce science quality Ocean Color data products. The VOST concluded that many characteristics were similar to earlier instruments, including SeaWiFS or MODIS Aqua. Though instrument performance and calibration risks do exist, it was concluded that programmatic and algorithm issues dominate concerns. Keywords: NPP, VIIRS, Ocean Color, satellite remote sensing, climate data record.

Most Amazing High Definition Image of Earth - Blue Marble 2012

NASA Image and Video Library

2017-12-08

January 25, 2012 *Updated February 2, 2012: According to Flickr, "The western hemisphere Blue Marble 2012 image has rocketed up to over 3.1 million views making it one of the all time most viewed images on the site after only one week." A 'Blue Marble' image of the Earth taken from the VIIRS instrument aboard NASA's most recently launched Earth-observing satellite - Suomi NPP. This composite image uses a number of swaths of the Earth's surface taken on January 4, 2012. The NPP satellite was renamed 'Suomi NPP' on January 24, 2012 to honor the late Verner E. Suomi of the University of Wisconsin. Suomi NPP is NASA's next Earth-observing research satellite. It is the first of a new generation of satellites that will observe many facets of our changing Earth. Suomi NPP is carrying five instruments on board. The biggest and most important instrument is The Visible/Infrared Imager Radiometer Suite or VIIRS. To read more about NASA's Suomi NPP go to: www.nasa.gov/npp Credit: NASA/NOAA/GSFC/Suomi NPP/VIIRS/Norman Kuring NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

Substrate-Dependence of Competitive Nucleotide Pyrophosphatase/Phosphodiesterase1 (NPP1) Inhibitors

PubMed Central

Lee, Sang-Yong; Sarkar, Soumya; Bhattarai, Sanjay; Namasivayam, Vigneshwaran; De Jonghe, Steven; Stephan, Holger; Herdewijn, Piet; El-Tayeb, Ali; Müller, Christa E.

2017-01-01

Nucleotide pyrophosphatase/phosphodiesterase type 1 (NPP1) is a membrane glycoprotein involved in the hydrolysis of extracellular nucleotides. Its major substrate is ATP which is converted to AMP and diphosphate. NPP1 was proposed as a new therapeutic target in brain cancer and immuno-oncology. Several NPP1 inhibitors have been reported to date, most of which were evaluated vs. the artificial substrate p-nitrophenyl 5′-thymidine monophosphate (p-Nph-5′-TMP). Recently, we observed large discrepancies in inhibitory potencies for a class of competitive NPP1 inhibitors when tested vs. the artificial substrate p-Nph-5′-TMP as compared to the natural substrate ATP. Therefore, the goal of the present study was to investigate whether inhibitors of human NPP1 generally display substrate-dependent inhibitory potency. Systematic evaluation of nucleotidic as well as non-nucleotidic NPP1 inhibitors revealed significant differences in determined Ki values for competitive, but not for non- and un-competitive inhibitors when tested vs. the frequently used artificial substrate p-Nph-5′-TMP as compared to ATP. Allosteric modulation of NPP1 by p-Nph-5′-TMP may explain these discrepancies. Results obtained using the AMP derivative p-nitrophenyl 5′-adenosine monophosphate (p-Nph-5′-AMP) as an alternative artificial substrate correlated much better with those employing the natural substrate ATP. PMID:28261095

Sensitivity of Spruce/Moss Boreal Forest Net Ecosystem Productivity to Seasonal Anomalies in Weather

NASA Technical Reports Server (NTRS)

Frolking, Steve

1997-01-01

Abstract. A process-oriented, daily time step model of a spruce/moss boreal ecosystem simulated 1994 and 1995 productivity for a Boreal Ecosystem-Atmosphere Study site near Thompson, Manitoba. Simulated black spruce net primary productivity (NPP) was 139 g C m(exp -2) in 1994 and 112 in 1995; feathermoss NPP was 13.0 g C m(exp -2) in 1994 and 9.7 in 1995; decomposition was 126 g C m(exp -2) in 1994 and 130 in 1995; net ecosystem productivity (NEP) was an uptake of 26.3 g C m(exp -2)in 1994 and 2.5 in 1995. A very dry period for the first half of the 1995 summer was the major cause of that year's lower productivity. Sensitivity simulations explored the impact of 2-month long warmer, cooler, wetter, and drier spells on ecosystem productivity. Warmer summers decreased spruce NPP, moss NPP, and NEP; cooler summers had the opposite effect. Earlier snowmelt (due to either warmer spring temperatures or reduced winter precipitation) increased moss and spruce NPP; later snowmelt had the opposite effect. The largest effect on decomposition was a 5% reduction due to a drier summer. One-month droughts (April through October) were also imposed on 1975 base year weather. Early summer droughts reduced moss annual NPP by -30-40%; summer droughts reduced spruce annual NPP by 10%; late summer droughts increased moss NPP by about 20% due to reduced respiration; May to September monthly droughts reduced heterotrophic respiration by about 10%. Variability in NEP was up to roughly +/- 35%. Finally, 1975 growing season precipitation was redistributed into frequent, small rainstorms and infrequent, large rainstorms. These changes had no effect on spruce NPP. Frequent rainstorms increased decomposition by a few percent, moss NPP by 50%, and NEP by 20%. Infrequent rainstorms decreased decomposition by 5%, moss NPP by 50% and NEP by 15%. The impact of anomalous weather patterns on productivity of this ecosystem depended on their timing during the year. Multiyear data sets are necessary to understand this behavior and test these types of models.

Estimating primary productivity of tropical oil palm in Malaysia using remote sensing technique and ancillary data

NASA Astrophysics Data System (ADS)

Kanniah, K. D.; Tan, K. P.; Cracknell, A. P.

2014-10-01

The amount of carbon sequestration by vegetation can be estimated using vegetation productivity. At present, there is a knowledge gap in oil palm net primary productivity (NPP) at a regional scale. Therefore, in this study NPP of oil palm trees in Peninsular Malaysia was estimated using remote sensing based light use efficiency (LUE) model with inputs from local meteorological data, upscaled leaf area index/fractional photosynthetically active radiation (LAI/fPAR) derived using UK-DMC 2 satellite data and a constant maximum LUE value from the literature. NPP values estimated from the model was then compared and validated with NPP estimated using allometric equations developed by Corley and Tinker (2003), Henson (2003) and Syahrinudin (2005) with diameter at breast height, age and the height of the oil palm trees collected from three estates in Peninsular Malaysia. Results of this study show that oil palm NPP derived using a light use efficiency model increases with respect to the age of oil palm trees, and it stabilises after ten years old. The mean value of oil palm NPP at 118 plots as derived using the LUE model is 968.72 g C m-2 year-1 and this is 188% - 273% higher than the NPP derived from the allometric equations. The estimated oil palm NPP of young oil palm trees is lower compared to mature oil palm trees (<10 years old), as young oil palm trees contribute to lower oil palm LAI and therefore fPAR, which is an important variable in the LUE model. In contrast, it is noted that oil palm NPP decreases with respect to the age of oil palm trees as estimated using the allomeric equations. It was found in this study that LUE models could not capture NPP variation of oil palm trees if LAI/fPAR is used. On the other hand, tree height and DBH are found to be important variables that can capture changes in oil palm NPP as a function of age.

Study on Net Primary Productivity over Complicated Mountainous Area based on Multi-Source Remote Sensing Data

NASA Astrophysics Data System (ADS)

Guan, X.; Shen, H.; Li, X.; Gan, W.

2017-12-01

Mountainous area hosts approximately a quarter of the global land surface, with complex climate and ecosystem conditions. More knowledge about mountainous ecosystem could highly advance our understanding of the global carbon cycle and climate change. Net Primary Productivity (NPP), the biomass increment of plants, is a widely used ecological indicator that can be obtained by remote sensing methods. However, limited by the defective characteristic of sensors, which cannot be long-term with enough spatial details synchronously, the mountainous NPP was far from being understood. In this study, a multi-sensor fusion framework was applied to synthesize a 1-km NPP series from 1982 to 2014 in mountainous southwest China, where elevation ranged from 76m to 6740m. The validation with field-measurements proved this framework greatly improved the accuracy of NPP (r=0.79, p<0.01). The detailed spatial and temporal analysis indicated that NPP variation trends changed from decreasing to increasing with the ascending elevation, as a result of a warmer and drier climate over the region. The correlation of NPP and temperature varied from negative to positive almost at the same elevation break-point of NPP trends, but the opposite for precipitation. This phenomenon was determined by the altitudinal and seasonally uneven allocation of climatic factors, as well as the downward run-off. What is more, it was indicated that the NPP variation showed three distinct stages at the year break-point of 1992 and 2002 over the region. The NPP in low-elevation area varied almost triple more drastic than the high-elevation area for all the three stages, due to the much greater change rate of precipitation. In summary, this study innovatively conducted a long-term and accurate NPP study on the not understood mountainous ecosystem with multi-source data, the framework and conclusions will be beneficial for the further cognition of global climate change.

Subsequent bone and metabolic responses of broilers to high-non-phytate phosphorus diets in the starter period.

PubMed

Baradaran, N; Shahir, M H; Asadi Kermani, Z

2017-08-01

1. An experiment was performed to elucidate the subsequent effects of high-non-phytate phosphorus (NPP) diets on growth performance, blood metabolites, bone characteristics and P retention of broilers fed on low-NPP grower diets. The 42-d study was designed as a 2 × 2 × 2 + 1 factorial, which included two starter NPP concentrations (4.5 and 5.5 g/kg; d 0-21), two grower NPP concentrations (1.5 and 2.3 g/kg; d 22-42), with or without phytase (1000 FTU/kg), with a reference diet containing an adequate NPP concentration over the course of the trial. 2. In the starter period, growth performance and P retention were not affected by experimental diets. The high-NPP diet increased plasma P concentration, increased tibia ash and tibia P contents and decreased plasma alkaline phosphatase (ALP) activity at d 21. 3. No significant interaction was observed between NPP concentrations in the starter and grower periods and phytase. The main effect data indicated that the increase in NPP concentration in the starter diets had no effects on growth performance in the grower period and overall. The high-NPP diet in the early stage of growth reduced plasma P concentration, plasma ALP activity and tibia ash content at d 42. The main effect data also showed that exogenous phytase increased body weight gain in the grower period and overall. 4. It can be concluded that feeding increased NPP diets have no effects on growth performance in the starter period. This feeding strategy results in negative effects on plasma P concentration and bone ash content at d 42. Also, exogenous phytase is effective in improving growth performance, bone characteristics and apparent P retention of growing broilers fed diets that are inadequate in phosphorus.

Investigating the Contribution of Climate Variables to Estimates of Net Primary Productivity in a Tropical Ecosystem in India

NASA Astrophysics Data System (ADS)

Tripathi, P.; Behera, M. D.; Behera, S. K.; Sahu, N.

2016-12-01

Investigating the impact of climate variables on net primary productivity is crucial to evaluate the ecosystem health and the status of forest type response to climate change. The objective of this paper is (1) to analyze the spatio-temporal pattern of net primary productivity (NPP) in a tropical forest ecosystem situated along the Himalayan foothills in India and (2) to investigate the continuous and delayed effects of climatic variables. Weapplied simple Monteith equation based Light use efficiency model for two dominant plant functional types; sal (Shorea robusta) forest and teak (Tectona grandis) plantation to estimate the NPP for a decadal period from 2001 to 2010. The impact of climate variables on NPP for these 10 years was seen by applying two correlation analyses; generalized linear modelling (GLM) and time lag correlation approach.The impact of different climate variables was observed to vary throughout the study period.A decline in mean NPP during 2002-2003, 2005 and 2008 to 2010 could be attributed to drought, increased vapour pressure deficit, and decreased humidity and solar radiation. In time lag correlation analysis, precipitation and humidity were observed to be the major variables affecting NPP; whereas combination of temperature, humidity and VPD showed dominant effect on NPP in GLM. Shorea robusta forest showed slightly higher NPP than that of Tectona grandis plantation throughout the study period. Highest decrease in NPP was observed during 2010,pertaining to lower solar radiation, humidity and precipitation along with increased VPD.Higher gains in NPP by sal during all years indicates their better adaptability to climate compared to teak. Contribution of different climatic variables through some link process is revealed in statistical analysis clearly indicates the co-dominance of all the variables in explaining NPP. Lacking of site specific meteorological observations and microclimate put constraint on broad level analyses.

Interactions between CO2 enhancement and N addition on net primary productivity and water-use efficiency in a mesocosm with multiple subtropical tree species.

PubMed

Yan, Junhua; Zhang, Deqiang; Liu, Juxiu; Zhou, Guoyi

2014-07-01

Carbon dioxide (CO2 ) enhancement (eCO2 ) and N addition (aN) have been shown to increase net primary production (NPP) and to affect water-use efficiency (WUE) for many temperate ecosystems, but few studies have been made on subtropical tree species. This study compared the responses of NPP and WUE from a mesocosm composing five subtropical tree species to eCO2 (700 ppm), aN (10 g N m(-2) yr(-1) ) and eCO2 × aN using open-top chambers. Our results showed that mean annual ecosystem NPP did not changed significantly under eCO2 , increased by 56% under aN and 64% under eCO2 × aN. Ecosystem WUE increased by 14%, 55%, and 61% under eCO2 , aN and eCO2 × aN, respectively. We found that the observed responses of ecosystem WUE were largely driven by the responses of ecosystem NPP. Statistical analysis showed that there was no significant interactions between eCO2 and aN on ecosystem NPP (P = 0.731) or WUE (P = 0.442). Our results showed that increasing N deposition was likely to have much stronger effects on ecosystem NPP and WUE than increasing CO2 concentration for the subtropical forests. However, different tree species responded quite differently. aN significantly increased annual NPP of the fast-growing species (Schima superba). Nitrogen-fixing species (Ormosia pinnata) grew significantly faster only under eCO2 × aN. eCO2 had no effects on annual NPP of those two species but significantly increased annual NPP of other two species (Castanopsis hystrix and Acmena acuminatissima). Differential responses of the NPP among different tree species to eCO2 and aN will likely have significant implications on the species composition of subtropical forests under future global change. © 2013 John Wiley & Sons Ltd.

NPP estimation and seasonal change research of Gansu province in northwest China

NASA Astrophysics Data System (ADS)

Han, Tao; Wang, Dawei; Hao, Xiaocui; Jiang, Youyan

2018-03-01

Based on GIS and remote sensing technology, this paper estimates the NPP of the 2015 year-round and every season of Gansu province in northwest China by using the CASA(Carnegie Ames Stanford Approach) light energy utilization model. The result shows that the total annual NPP of Gansu province gradually decline from southeast to northwest in the space, which is in accordance with the water and heat condition in Gansu province. The results show that the summer NPP in Gansu Province is the maximum in each season. The maximum value of summer NPP in Gansu Province reached 695 (gCm-2•season-1), and the maximum value was 473 in spring, and 288 in the autumn, and the NPP in the winter in Gansu province were under 60. The fluctuation range of NPP value is large, this is due to the diversity of ecosystem types in Gansu province, including desert, grassland, farmland and forest, among them, the grassland area is the largest, and the grassland type is very diverse, the grassland coverage is obviously different, especially the low coverage grassland growth is affected by precipitation and temperature and other meteorological factors obviously.

Investigation on the inclusion interaction of 4-sulfonatocalix[n]arenes with 1-(4-nitrophenyl)piperazine

NASA Astrophysics Data System (ADS)

Zhang, Yongbin; Chao, Jianbin; Zhao, Shuhui; Xu, Penghao; Wang, Hongfang; Guo, Zhiqiang; Liu, Diansheng

2014-11-01

The inclusion behaviors of 4-Sulfonatocalix[n]arenes (SCXn) (n = 4, 6, 8) with 1-(4-nitrophenyl)piperazine (NPP) were investigated by UV spectroscopy and fluorescence spectroscopy at different pH values (pH = 3.05, 6.50, 8.40). The UV absorption and fluorescence intensity of NPP remarkably increased in presence of SCXn revealing formation of the inclusion complexes between NPP and SCXn. Moreover, the formation constants (K) of inclusion complexes were also determined by the non-linear fitting method, and the obtained data showed that the formation constants decreased gradually with the increasing of the pH value. When the pH value was 3.05, the formation constant of NPP with SCX8 reached a maximum of 1.7 × 107 L mol-1. The stoichiometric ratio was verified to be 1:1 by the continuous variation method. Meanwhile FT-IR and DSC analysis also indicated that NPP could form the inclusion complex with SCXn. In order to explore the inclusion mechanism of NPP with SCXn, 1H NMR and molecular modeling studies were carried out and experimental results showed that the part of benzene ring of NPP penetrated into the hydrophobic cavity of SCXn.

The utility of estimating net primary productivity over Alaska using baseline AVHRR data

USGS Publications Warehouse

Markon, C.J.; Peterson, Kim M.

2002-01-01

Net primary productivity (NPP) is a fundamental ecological variable that provides information about the health and status of vegetation communities. The Normalized Difference Vegetation Index, or NDVI, derived from the Advanced Very High Resolution Radiometer (AVHRR) is increasingly being used to model or predict NPP, especially over large remote areas. In this article, seven seasonally based metrics calculated from a seven-year baseline NDVI dataset were used to model NPP over Alaska, USA. For each growing season, they included maximum, mean and summed NDVI, total days, product of total days and maximum NDVI, an integral estimate of NDVI and a summed product of NDVI and solar radiation. Field (plot) derived NPP estimates were assigned to 18 land cover classes from an Alaskan statewide land cover database. Linear relationships between NPP and each NDVI metric were analysed at four scales: plot, 1-km, 10-km and 20-km pixels. Results show moderate to poor relationship between any of the metrics and NPP estimates for all data sets and scales. Use of NDVI for estimating NPP may be possible, but caution is required due to data seasonality, the scaling process used and land surface heterogeneity.

NPP Satellite Launch

NASA Image and Video Library

2011-10-28

The Satellite Operations Facility of the National Oceanic and Atmospheric Administration (NOAA) is seen here minutes before the launch of the National Polar-orbiting Operational Environmental Satellite System Preparatory Project (NPP) on Friday, Oct. 28, 2011 in Suitland, Md. NPP is a joint venture between NASA and NOAA, and is the nation's newest Earth-observing satellite, which will provide data on climate change science, allow for accurate weather forecasts and advance warning for severe weather. NPP was launched from Vandenberg Air Force Base in California. Photo Credit: (NASA/Carla Cioffi)

Net primary productivity, allocation pattern and carbon use efficiency in an apple orchard assessed by integrating eddy covariance, biometric and continuous soil chamber measurements

NASA Astrophysics Data System (ADS)

Zanotelli, D.; Montagnani, L.; Manca, G.; Tagliavini, M.

2013-05-01

Carbon use efficiency (CUE), the ratio of net primary production (NPP) over gross primary production (GPP), is a functional parameter that could possibly link the current increasingly accurate global GPP estimates with those of net ecosystem exchange, for which global predictors are still unavailable. Nevertheless, CUE estimates are actually available for only a few ecosystem types, while information regarding agro-ecosystems is scarce, in spite of the simplified spatial structure of these ecosystems that facilitates studies on allocation patterns and temporal growth dynamics. We combined three largely deployed methods, eddy covariance, soil respiration and biometric measurements, to assess monthly values of CUE, NPP and allocation patterns in different plant organs in an apple orchard during a complete year (2010). We applied a measurement protocol optimized for quantifying monthly values of carbon fluxes in this ecosystem type, which allows for a cross check between estimates obtained from different methods. We also attributed NPP components to standing biomass increments, detritus cycle feeding and lateral exports. We found that in the apple orchard, both net ecosystem production and gross primary production on a yearly basis, 380 ± 30 g C m-2 and 1263 ± 189 g C m-2 respectively, were of a magnitude comparable to those of natural forests growing in similar climate conditions. The largest differences with respect to forests are in the allocation pattern and in the fate of produced biomass. The carbon sequestered from the atmosphere was largely allocated to production of fruit: 49% of annual NPP was taken away from the ecosystem through apple production. Organic material (leaves, fine root litter, pruned wood and early fruit falls) contributing to the detritus cycle was 46% of the NPP. Only 5% was attributable to standing biomass increment, while this NPP component is generally the largest in forests. The CUE, with an annual average of 0.71 ± 0.12, was higher than the previously suggested constant values of 0.47-0.50. Low nitrogen investment in fruit, the limited root apparatus, and the optimal growth temperature and nutritional condition observed at the site are suggested to be explanatory variables for the high CUE observed.

Tegumental Phosphodiesterase SmNPP-5 Is a Virulence Factor for Schistosomes ▿

PubMed Central

Bhardwaj, Rita; Krautz-Peterson, Greice; Da'dara, Akram; Tzipori, Saul; Skelly, Patrick J.

2011-01-01

The intravascular trematode Schistosoma mansoni is a causative agent of schistosomiasis, a disease that constitutes a major health problem globally. In this study we cloned and characterized the schistosome tegumental phosphodiesterase SmNPP-5 and evaluated its role in parasite virulence. SmNPP-5 is a 52.5-kDa protein whose gene is rapidly turned on in the intravascular parasitic life stages, following invasion of the definitive host. Highest expression is found in mated adult males. As revealed by immunofluorescence analysis, SmNPP-5 protein is found prominently in the dorsal surface of the tegument of males. Localization by immuno-electron microscopy illustrates a unique pattern of immunogold-labeled SmNPP-5 within the tegument; some immunogold particles are scattered throughout the tissue, but many are clustered in tight arrays. To determine the importance of the protein for the parasites, RNA interference (RNAi) was employed to knock down expression of the SmNPP-5-encoding gene in schistosomula and adult worms. Both quantitative real-time PCR (qRT-PCR) and Western blotting confirmed successful and robust gene suppression. In addition, the suppression and the ectolocalization of this enzyme in live parasites were evident because of a significantly impaired ability of the suppressed parasites to hydrolyze exogenously added phosphodiesterase substrate p-nitrophenyl 5′-dTMP (p-Nph-5′-TMP). The effects of suppressing expression of the SmNPP-5 gene in vivo were tested by injecting parasites into mice. It was found that, unlike controls, parasites whose SmNPP-5 gene was demonstrably suppressed at the time of host infection were greatly impaired in their ability to establish infection. These results demonstrate that SmNPP-5 is a virulence factor for schistosomes. PMID:21825060

Estimation of the possible influence of future climate changes on biodiversity in terrestrial ecosystem

NASA Astrophysics Data System (ADS)

Noda, H. M.; Nishina, K.; Ito, A.

2015-12-01

In recent decades, climate change has progressed worldwide and their influences on ecosystem structure and function that provide various goods and services to humans' well-being are of the greatest concerns. The ecosystem function and services are tightly coupled with the biodiversity, particularly via food web and biogeochemical cycles and here carbon is one of the central elements. The photosynthetic carbon fixation by plants, which forms the basis of the food web, is known to be highly sensitive to meteorological changes including radiation, temperature, precipitation and CO2 concentration. Thus an analysis of the effect of future climate change on the carbon cycle processes including photosynthetic production in a biogeographical region, which is important from the viewpoint of the biodiversity conservation, such as "biodiversity hotspot", might enable us to discuss the relevance between climate change and biodiversity.In ISI-MIP (Inter-Sectoral Impact Model Intercomparison Project) phase 1, we have estimated NPP (net primary production), plant biomass and soil organic carbon by seven global biome models under climate conditions from 1901 to 2100 based on four RCPs (Representative Concentration Pathways for 2.6, 4.5, 6.0, and 8.5 W m-2 stabilization targets) and five global climate models. In the present study, we analyzed these outputs to reveal the effects of changes on NPP, plant biomass and soil organic carbon in 20 biodiversity hotspots in various climatic regions. Although NPP of whole world tended to increase under RCP 8.5 W m-2 scenario, some biome models have shown that NPP of the hotspots in tropical regions decrease.

[Collaborative application of BEPS at different time steps.

PubMed

Lu, Wei; Fan, Wen Yi; Tian, Tian

2016-09-01

BEPSHourly is committed to simulate the ecological and physiological process of vegetation at hourly time steps, and is often applied to analyze the diurnal change of gross primary productivity (GPP), net primary productivity (NPP) at site scale because of its more complex model structure and time-consuming solving process. However, daily photosynthetic rate calculation in BEPSDaily model is simpler and less time-consuming, not involving many iterative processes. It is suitable for simulating the regional primary productivity and analyzing the spatial distribution of regional carbon sources and sinks. According to the characteristics and applicability of BEPSDaily and BEPSHourly models, this paper proposed a method of collaborative application of BEPS at daily and hourly time steps. Firstly, BEPSHourly was used to optimize the main photosynthetic parameters: the maximum rate of carboxylation (V c max ) and the maximum rate of photosynthetic electron transport (J max ) at site scale, and then the two optimized parameters were introduced into BEPSDaily model to estimate regional NPP at regional scale. The results showed that optimization of the main photosynthesis parameters based on the flux data could improve the simulate ability of the model. The primary productivity of different forest types in descending order was deciduous broad-leaved forest, mixed forest, coniferous forest in 2011. The collaborative application of carbon cycle models at different steps proposed in this study could effectively optimize the main photosynthesis parameters V c max and J max , simulate the monthly averaged diurnal GPP, NPP, calculate the regional NPP, and analyze the spatial distribution of regional carbon sources and sinks.

The kinetics of aerosol particle formation and removal in NPP severe accidents

NASA Astrophysics Data System (ADS)

Zatevakhin, Mikhail A.; Arefiev, Valentin K.; Semashko, Sergey E.; Dolganov, Rostislav A.

2016-06-01

Severe Nuclear Power Plant (NPP) accidents are accompanied by release of a massive amount of energy, radioactive products and hydrogen into the atmosphere of the NPP containment. A valid estimation of consequences of such accidents can only be carried out through the use of the integrated codes comprising a description of the basic processes which determine the consequences. A brief description of a coupled aerosol and thermal-hydraulic code to be used for the calculation of the aerosol kinetics within the NPP containment in case of a severe accident is given. The code comprises a KIN aerosol unit integrated into the KUPOL-M thermal-hydraulic code. Some features of aerosol behavior in severe NPP accidents are briefly described.

The kinetics of aerosol particle formation and removal in NPP severe accidents

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zatevakhin, Mikhail A.; Arefiev, Valentin K.; Semashko, Sergey E.

2016-06-08

Severe Nuclear Power Plant (NPP) accidents are accompanied by release of a massive amount of energy, radioactive products and hydrogen into the atmosphere of the NPP containment. A valid estimation of consequences of such accidents can only be carried out through the use of the integrated codes comprising a description of the basic processes which determine the consequences. A brief description of a coupled aerosol and thermal–hydraulic code to be used for the calculation of the aerosol kinetics within the NPP containment in case of a severe accident is given. The code comprises a KIN aerosol unit integrated into themore » KUPOL-M thermal–hydraulic code. Some features of aerosol behavior in severe NPP accidents are briefly described.« less

Simulating Spatiotemporal Dynamics of Sichuan Grassland Net Primary Productivity Using the CASA Model and In Situ Observations

PubMed Central

Tang, Chuanjiang; Fu, Xinyu; Jiang, Dong; Zhang, Xinyue; Zhou, Su

2014-01-01

Net primary productivity (NPP) is an important indicator for grassland resource management and sustainable development. In this paper, the NPP of Sichuan grasslands was estimated by the Carnegie-Ames-Stanford Approach (CASA) model. The results were validated with in situ data. The overall precision reached 70%; alpine meadow had the highest precision at greater than 75%, among the three types of grasslands validated. The spatial and temporal variations of Sichuan grasslands were analyzed. The absorbed photosynthetic active radiation (APAR), light use efficiency (ε), and NPP of Sichuan grasslands peaked in August, which was a vigorous growth period during 2011. High values of APAR existed in the southwest regions in altitudes from 2000 m to 4000 m. Light use efficiency (ε) varied in the different types of grasslands. The Sichuan grassland NPP was mainly distributed in the region of 3000–5000 m altitude. The NPP of alpine meadow accounted for 50% of the total NPP of Sichuan grasslands. PMID:25250396

KSC-2011-7020

NASA Image and Video Library

2011-09-06

VANDENBERG AIR FORCE BASE, Calif. – In a clean room inside the Astrotech Payload Processing Facility at Vandenberg Air Force Base in California, a technician performs a torque bolt stress test on NASA’s National Polar-orbiting Operational Environmental Satellite System Preparatory Project (NPP). Technicians will perform many tests and checkouts on the satellite system to prepare it for launch. NPP represents a critical first step in building the next-generation of Earth-observing satellites. NPP will carry the first of the new sensors developed for this satellite fleet, now known as the Joint Polar Satellite System (JPSS), to be launched in 2016. NPP is the bridge between NASA’s Earth Observing System (EOS) satellites and the forthcoming series of JPSS satellites. The mission will test key technologies and instruments for the JPSS missions. NPP is targeted to launch Oct. 25 from Space Launch Complex-2 aboard a United Launch Alliance Delta II rocket. For more information, visit http://www.nasa.gov/NPP. Photo credit: NASA/30th Communications Squadron, VAFB

KSC-2011-7019

NASA Image and Video Library

2011-09-01

VANDENBERG AIR FORCE BASE, Calif. – In a clean room inside the Astrotech Payload Processing Facility at Vandenberg Air Force Base in California, a large sign is placed on the test stand holding NASA’s National Polar-orbiting Operational Environmental Satellite System Preparatory Project (NPP). The satellite system is awaiting test and checkout procedures to prepare it for launch. NPP represents a critical first step in building the next-generation of Earth-observing satellites. NPP will carry the first of the new sensors developed for this satellite fleet, now known as the Joint Polar Satellite System (JPSS), to be launched in 2016. NPP is the bridge between NASA’s Earth Observing System (EOS) satellites and the forthcoming series of JPSS satellites. The mission will test key technologies and instruments for the JPSS missions. NPP is targeted to launch Oct. 25 from Space Launch Complex-2 aboard a United Launch Alliance Delta II rocket. For more information, visit http://www.nasa.gov/NPP. Photo credit: NASA/30th Communications Squadron, VAFB

KSC-2011-7021

NASA Image and Video Library

2011-09-06

VANDENBERG AIR FORCE BASE, Calif. – In a clean room inside the Astrotech Payload Processing Facility at Vandenberg Air Force Base in California, technicians perform a torque bolt stress test on NASA’s National Polar-orbiting Operational Environmental Satellite System Preparatory Project (NPP). Technicians will perform many tests and checkouts on the satellite system to prepare it for launch. NPP represents a critical first step in building the next-generation of Earth-observing satellites. NPP will carry the first of the new sensors developed for this satellite fleet, now known as the Joint Polar Satellite System (JPSS), to be launched in 2016. NPP is the bridge between NASA’s Earth Observing System (EOS) satellites and the forthcoming series of JPSS satellites. The mission will test key technologies and instruments for the JPSS missions. NPP is targeted to launch Oct. 25 from Space Launch Complex-2 aboard a United Launch Alliance Delta II rocket. For more information, visit http://www.nasa.gov/NPP. Photo credit: NASA/30th Communications Squadron, VAFB

Monitoring Bio-Optical Processes Using NPP-VIIRS and MODIS-Aqua Ocean Color Products

DTIC Science & Technology

2013-01-01

shall be subject to any penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number...account for satellite sensor and solar zenith angles. Additionally, the Bidirectional Reflectance Distribution Function ( BRDF ) of the water particles is...similarly dependent on satellite and solar zenith and azimuth angles 4 . The influence of BRDF is more pronounced in a high scattering environment

Patterns of new versus recycled primary production in the terrestrial biosphere

PubMed Central

Cleveland, Cory C.; Houlton, Benjamin Z.; Smith, W. Kolby; Marklein, Alison R.; Reed, Sasha C.; Parton, William; Del Grosso, Stephen J.; Running, Steven W.

2013-01-01

Nitrogen (N) and phosphorus (P) availability regulate plant productivity throughout the terrestrial biosphere, influencing the patterns and magnitude of net primary production (NPP) by land plants both now and into the future. These nutrients enter ecosystems via geologic and atmospheric pathways and are recycled to varying degrees through the plant–soil–microbe system via organic matter decay processes. However, the proportion of global NPP that can be attributed to new nutrient inputs versus recycled nutrients is unresolved, as are the large-scale patterns of variation across terrestrial ecosystems. Here, we combined satellite imagery, biogeochemical modeling, and empirical observations to identify previously unrecognized patterns of new versus recycled nutrient (N and P) productivity on land. Our analysis points to tropical forests as a hotspot of new NPP fueled by new N (accounting for 45% of total new NPP globally), much higher than previous estimates from temperate and high-latitude regions. The large fraction of tropical forest NPP resulting from new N is driven by the high capacity for N fixation, although this varies considerably within this diverse biome; N deposition explains a much smaller proportion of new NPP. By contrast, the contribution of new N to primary productivity is lower outside the tropics, and worldwide, new P inputs are uniformly low relative to plant demands. These results imply that new N inputs have the greatest capacity to fuel additional NPP by terrestrial plants, whereas low P availability may ultimately constrain NPP across much of the terrestrial biosphere. PMID:23861492

Divergence in Forest-Type Response to Climate and Weather: Evidence for Regional Links Between Forest-Type Evenness and Net Primary Productivity

USGS Publications Warehouse

Bradford, J.B.

2011-01-01

Climate change is altering long-term climatic conditions and increasing the magnitude of weather fluctuations. Assessing the consequences of these changes for terrestrial ecosystems requires understanding how different vegetation types respond to climate and weather. This study examined 20 years of regional-scale remotely sensed net primary productivity (NPP) in forests of the northern Lake States to identify how the relationship between NPP and climate or weather differ among forest types, and if NPP patterns are influenced by landscape-scale evenness of forest-type abundance. These results underscore the positive relationship between temperature and NPP. Importantly, these results indicate significant differences among broadly defined forest types in response to both climate and weather. Essentially all weather variables that were strongly related to annual NPP displayed significant differences among forest types, suggesting complementarity in response to environmental fluctuations. In addition, this study found that forest-type evenness (within 8 ?? 8 km2 areas) is positively related to long-term NPP mean and negatively related to NPP variability, suggesting that NPP in pixels with greater forest-type evenness is both higher and more stable through time. This is landscape- to subcontinental-scale evidence of a relationship between primary productivity and one measure of biological diversity. These results imply that anthropogenic or natural processes that influence the proportional abundance of forest types within landscapes may influence long-term productivity patterns. ?? 2011 Springer Science+Business Media, LLC (outside the USA).

Assessment of safety distance between components of nuclear plant and study of the vulnerabiliy of the damage caused by an explosion

NASA Astrophysics Data System (ADS)

Ismaila, Aminu; Md Kasmani, Rafiziana; Meng-Hock, Koh; Termizi Ramli, Ahmad

2017-10-01

This paper deals with the assessment of external explosion, resulting from accidental release of jet fuel from the large commercial airliner in the nuclear power plant (NPP). The study used three widely prediction methods such as Trinitrotoluene (TNT), multi energy (TNO) and Baker-strehow (BST) to determine the unconfined vapour cloud explosion (UVCE) overpressure within the distances of 100-1400 m from the first impact location. The containment building was taken as the reference position. The fatalities of persons and damage of structures was estimated using probit methodology. Analysis of the results shows that both reactor building and control-room will be highly damaged with risk consequences and probability, depending on the assumed position of the crash. The structures at the radial distance of 600 m may suffer major structural damage with probability ranging from 25 to 100%. The minor structural damage was observed throughout the bounds of the plant complex. The people working within 250 m radius may get affected with different fatality ranging from 28 to 100%. The findings of this study is valuable to evaluate the safety improvement needed on the NPP site and on the risk and consequences associated with the hydrocarbon fuel release/fires due to external hazards.

Critical soil water period for primary production in Chihuahuan Desert ecosystems

USDA-ARS?s Scientific Manuscript database

In desert ecosystems where water is the main limiting factor, it is expected that net primary production (NPP) is largely determined by precipitation. However, precipitation alone often explains only a small portion of the variation in NPP, and the critical precipitation period for NPP varies by pla...

76 FR 46330 - NUREG-1934, Nuclear Power Plant Fire Modeling Application Guide (NPP FIRE MAG); Second Draft...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-08-02

... NUCLEAR REGULATORY COMMISSION [NRC-2009-0568] NUREG-1934, Nuclear Power Plant Fire Modeling Application Guide (NPP FIRE MAG); Second Draft Report for Comment AGENCY: Nuclear Regulatory Commission... 1023259), ``Nuclear Power Plant Fire Modeling Application Guide (NPP FIRE MAG), Second Draft Report for...

Effects of topography on simulated net primary productivity at landscape scale.

PubMed

Chen, X F; Chen, J M; An, S Q; Ju, W M

2007-11-01

Local topography significantly affects spatial variations of climatic variables and soil water movement in complex terrain. Therefore, the distribution and productivity of ecosystems are closely linked to topography. Using a coupled terrestrial carbon and hydrological model (BEPS-TerrainLab model), the topographic effects on the net primary productivity (NPP) are analyzed through four modelling experiments for a 5700 km(2) area in Baohe River basin, Shaanxi Province, northwest of China. The model was able to capture 81% of the variability in NPP estimated from tree rings, with a mean relative error of 3.1%. The average NPP in 2003 for the study area was 741 gCm(-2)yr(-1) from a model run including topographic effects on the distributions of climate variables and lateral flow of ground water. Topography has considerable effect on NPP, which peaks near 1350 m above the sea level. An elevation increase of 100 m above this level reduces the average annual NPP by about 25 gCm(-2). The terrain aspect gives rise to a NPP change of 5% for forests located below 1900 m as a result of its influence on incident solar radiation. For the whole study area, a simulation totally excluding topographic effects on the distributions of climatic variables and ground water movement overestimated the average NPP by 5%.

Differential detergent resistance of the apical and basolateral NPPases: relationship with polarized targeting.

PubMed

Delaunay, Jean-Louis; Breton, Michelyne; Goding, James W; Trugnan, Germain; Maurice, Michèle

2007-03-15

Targeting of glycosylphosphatidylinositol-anchored proteins to the apical surface of epithelial cells involves clustering in Triton X-100-resistant membrane microdomains or rafts. The role of these microdomains in sorting transmembrane proteins is more questionable because, unlike glycosylphosphatidylinositol-anchored proteins, apical transmembrane proteins are rather soluble in Triton X-100. They are, however, resistant to milder detergents such as Lubrol WX or Tween 20. It has been proposed that specific membrane microdomains, defined by resistance to these detergents, would carry transmembrane proteins to the apical surface. We have used MDCK cells stably transfected with the apical and basolateral pyrophosphatases/phosphodiesterases, NPP3 and NPP1, to examine the relationship between detergent resistance and apical targeting. The apically expressed wild-type NPP3 was insoluble in Lubrol WX whereas wild-type NPP1, which is expressed basolaterally, was essentially soluble. By using tail mutants and chimeric constructs that combine the cytoplasmic, transmembrane and extracellular domains of NPP1 and NPP3, we show that there is not a strict correlation between detergent resistance and apical targeting. Lubrol resistance is an intrinsic property of NPP3, which is acquired early during the biosynthetic process irrespective of its final destination, and depends on positively charged residues in its cytoplasmic tail.

Modeling and statistical analysis of feedback between NPP (MODIS NPP) and temperature for forest area Yenisei River

NASA Astrophysics Data System (ADS)

Kukoba, Nikolay; Ivanova, Yulia; Saltykov, Mikhail

Assimilation of carbon by green plants or net primary production (NPP) is one of the most important processes. It provide qualitative and quantitative estimates of the events occurring in the biosphere. Carbon assimilated by plants is used by them to increase their biomass and is a main process of food chains on Earth. NPP is highly variable in time and space. It may depend on physical factors such as temperature, humidity and concentration of nutrients in the soil, etc. And also depends on the types of vegetation (woody, herbaceous, coniferous, and deciduous, etc.). In this regard, it is very important to understand what kind of climate factor is a limiting factor of NPP in the given time and place. For this aim a statistical analysis of the feedback between NPP (MODIS NPP) and the temperature of the forest zone Yenisey River has been performed. We used the time series of NPP for studied territory between 2000 and 2012. The time series of temperature were calculated using the data from the satellite measurements (MODISTERRA) and the global network of weather stations. The considered territory is situated in the Yenisey River basin with diverse natural landscapes - from forest-tundra in the North to alpine meadows in the West Sayan Mountains in the South. This territory extends along the Yenisey River from north to south for about 2000 km. Plains and mountainous areas have been investigated separately. Mountain forests are located in the West Sayan and altitudinal zonation varies from 500 to 2000 m a.s.l. In order to investigate the causal relationships between temperature and NPP we applied the method of Convergent Cross-Mapping (CCM) (Sugihara et al., Science. 2012. V. 338. P. 496-500). This method in some case allows to determine what is a reason and what is consequence, that cannot be definded by simple correlation. It has been shown that the best results are obtained for the 8 -day composite satellite data during the growing season (MOD17A2, MOD11A2). By means of this method we obtained estimates of feedback strength between NPP and temperature. Application of this method for the study of CCM link between temperature and NPP was held for the first time.

Impact of response criteria (tibia ash weight vs. percent) on phytase relative non phytate phosphorus equivalance.

PubMed

Li, W; Angel, R; Kim, S-W; Jiménez-Moreno, E; Proszkowiec-Weglarz, M; Plumstead, P W

2015-09-01

The current study was conducted to evaluate the impacts of using tibia ash percentage or ash weight as the response criteria on estimated phytase relative equivalence. Straight run broilers were fed treatment (Trt) diets from 7 to 21 d age (6 birds/pen, 8 pens/Trt). The corn-soy based Trt were formulated to contain 0.80% Ca and 4 non-phytate phosphorus (nPP) concentrations (0.20, 0.27, 0.34, and 0.40%). Monocalcium phosphate was the inorganic phosphate source added to achieve 4 different dietary nPP concentrations and against which the nPP relative equivalence of phytase was determined. A 6-phytase (Danisco Animal Nutrition, DuPont Industrial Biosciences, Marlborough, UK) was added at 500 or 1,000 phytase unit ( FTU: )/kg to the 0.20% nPP diet resulting 6 total Trts. Tibia ash was determined at 21 d age. Phytase fed at 500 or 1,000 FTU/kg increased tibia ash weight and ash percentage compared to that of birds fed 0.20% nPP diet without phytase (P<0.05). Graded nPP were log transformed and regressed against tibia ash (weight and percentage) to calculate phytase nPP relative equivalence. The R2 obtained from pen value regressions were 0.81 and 0.84, for tibia ash weight and percentage, respectively. Ash percentage from birds fed 500 and 1,000 FTU phytase/kg fell within the range obtained with the MCP additions. Ash weight (842 mg/tibia) from birds fed 1,000 FTU phytase/kg exceeded (P<0.05) maximum weight (773 mg/tibia) measured in birds fed the greatest nPP Trt (0.40%), thus the nPP relative equivalence was only calculated in birds fed 500 FTU phytase/kg Trt. The nPP relative equivalence in birds fed 500 FTU phytase/kg were 0.117 and 0.168% based on ash percentage and weight, respectively (P<0.05). The nPP relative equivalence in birds fed 1,000 FTU phytase/kg was 0.166% for ash percentage. Results suggested that ash weight better reflects the amount of bone mineralization as compared to ash percentage and using ash percentage may lead to an underestimation of phytase efficacy. © 2015 Poultry Science Association Inc.

[Worker heat disorders at the Fukushima Daiichi nuclear power plant].

PubMed

Tsuji, Masayoshi; Kakamu, Takeyasu; Hayakawa, Takehito; Kumagai, Tomohiro; Hidaka, Tomoo; Kanda, Hideyuki; Fukushima, Tetsuhito

2013-01-01

Ever since the Fukushima Daiichi nuclear power plant (NPP) accident, every day about 3,000 workers have been working to repair the situation. The frequent occurrence of heat disorders has been a concern for the workers wearing protective clothing with poor ventilation. We have been analyzing the heat disorder problem since the accident in order to come up with a solution to prevent future heat disorder incidents among Fukushima Daiichi NPP accident clean-up workers. From March 22 to September 16, 2011, the Fukushima Labor Bureau assessed 43 cases of nuclear power plant workers with heat disorders. Age of subject, month and time of occurrence, temperature, and humidity were examined for each case, as well as the severity of heat disorders. The grade of severity was divided into Grade I and Grade II or higher. Then, age, temperature, and humidity were analyzed using the Mann-Whitney Utest, and age, temperature, humidity, and presence or absence of a cool-vest were analyzed using the χ(2) test and logistic regression analysis. SPSS version 17.0 statistical software was used with a level of significance of p< 0.05. Heat disorders occurred most frequently in subjects in their 40s (30.2%), followed by those in their 30s (25.6%), mostly in July (46.5%) between 7 am and 12 pm (69.8%). Heat disorders occurred most frequently in environments with temperatures more than 25°C (76.7%) and humidity of 70-80% (39.5%). Heat disorders of Grade II or higher occurred in 10 cases, 5 of which were in June. According to statistical analysis, there were no significant differences in difference of severity for all factors. Heat disorders usually occur in workers aged 45-60; however, cases of heat disorders at the Fukushima Daiichi NPP occurred in clean-up workers at the relatively younger ages of 30-40, suggesting the need for heat disorder prevention measures for these younger workers. Heat disorder cases primarily occurred in the morning, necessitating preventive measures for the early hours of the day. In addition, because heat disorders of Grade II or higher occurred in June in 5 of 10 cases, we believe heat disorder precautions should be implemented from June. The lack of significant difference in severity difference may be attributable to the small number of cases or other factors. We think Fukushima Daiichi NPP accident clean-up workers need heat disorder prevention measures for their safety, based on the results of this study.

Elevated carbon dioxide and ozone alter productivity and ecosystem carbon content in northern temperate forests.

PubMed

Talhelm, Alan F; Pregitzer, Kurt S; Kubiske, Mark E; Zak, Donald R; Campany, Courtney E; Burton, Andrew J; Dickson, Richard E; Hendrey, George R; Isebrands, J G; Lewin, Keith F; Nagy, John; Karnosky, David F

2014-08-01

Three young northern temperate forest communities in the north-central United States were exposed to factorial combinations of elevated carbon dioxide (CO2 ) and tropospheric ozone (O3 ) for 11 years. Here, we report results from an extensive sampling of plant biomass and soil conducted at the conclusion of the experiment that enabled us to estimate ecosystem carbon (C) content and cumulative net primary productivity (NPP). Elevated CO2 enhanced ecosystem C content by 11%, whereas elevated O3 decreased ecosystem C content by 9%. There was little variation in treatment effects on C content across communities and no meaningful interactions between CO2 and O3 . Treatment effects on ecosystem C content resulted primarily from changes in the near-surface mineral soil and tree C, particularly differences in woody tissues. Excluding the mineral soil, cumulative NPP was a strong predictor of ecosystem C content (r(2) = 0.96). Elevated CO2 enhanced cumulative NPP by 39%, a consequence of a 28% increase in canopy nitrogen (N) content (g N m(-2) ) and a 28% increase in N productivity (NPP/canopy N). In contrast, elevated O3 lowered NPP by 10% because of a 21% decrease in canopy N, but did not impact N productivity. Consequently, as the marginal impact of canopy N on NPP (∆NPP/∆N) decreased through time with further canopy development, the O3 effect on NPP dissipated. Within the mineral soil, there was less C in the top 0.1 m of soil under elevated O3 and less soil C from 0.1 to 0.2 m in depth under elevated CO2 . Overall, these results suggest that elevated CO2 may create a sustained increase in NPP, whereas the long-term effect of elevated O3 on NPP will be smaller than expected. However, changes in soil C are not well-understood and limit our ability to predict changes in ecosystem C content. © 2014 The Authors Global Change Biology Published by John Wiley & Sons Ltd.

Importance of disturbance history on net primary productivity in the world's most productive forests and implications for the global carbon cycle.

PubMed

Volkova, Liubov; Roxburgh, Stephen H; Weston, Christopher J; Benyon, Richard G; Sullivan, Andrew L; Polglase, Philip J

2018-05-14

Analysis of growth and biomass turnover in natural forests of Eucalyptus regnans, the world's tallest angiosperm, reveals it is also the world's most productive forest type, with fire disturbance an important mediator of net primary productivity (NPP). A comprehensive empirical database was used to calculate the averaged temporal pattern of NPP from regeneration to 250 years age. NPP peaks at 23.1 ± 3.8 (95% interquantile range) Mg C ha -1  year -1 at age 14 years, and declines gradually to about 9.2 ± 0.8 Mg C ha -1  year -1 at 130 years, with an average NPP over 250 years of 11.4 ± 1.1 Mg C ha -1  year -1 , a value similar to the most productive temperate and tropical forests around the world. We then applied the age-class distribution of E. regnans resulting from relatively recent historical fires to estimate current NPP for the forest estate. Values of NPP were 40% higher (13 Mg C ha -1  year -1 ) than if forests were assumed to be at maturity (9.2 Mg C ha -1  year -1 ). The empirically derived NPP time series for the E. regnans estate was then compared against predictions from 21 global circulation models, showing that none of them had the capacity to simulate a post-disturbance peak in NPP, as found in E. regnans. The potential importance of disturbance impacts on NPP was further tested by applying a similar approach to the temperate forests of conterminous United States and of China. Allowing for the effects of disturbance, NPP summed across both regions was on average 11% (or 194 Tg C/year) greater than if all forests were assumed to be in a mature state. The results illustrate the importance of accounting for past disturbance history and growth stage when estimating forest primary productivity, with implications for carbon balance modelling at local to global scales. © 2018 John Wiley & Sons Ltd.

Degradation of net primary production in a semiarid rangeland

NASA Astrophysics Data System (ADS)

Jackson, Hasan; Prince, Stephen D.

2016-08-01

Anthropogenic land degradation affects many biogeophysical processes, including reductions of net primary production (NPP). Degradation occurs at scales from small fields to continental and global. While measurement and monitoring of NPP in small areas is routine in some studies, for scales larger than 1 km2, and certainly global, there is no regular monitoring and certainly no attempt to measure degradation. Quantitative and repeatable techniques to assess the extent of deleterious effects and monitor changes are needed to evaluate its effects on, for example, economic yields of primary products such as crops, lumber, and forage, and as a measure of land surface properties which are currently missing from dynamic global vegetation models, assessments of carbon sequestration, and land surface models of heat, water, and carbon exchanges. This study employed the local NPP scaling (LNS) approach to identify patterns of anthropogenic degradation of NPP in the Burdekin Dry Tropics (BDT) region of Queensland, Australia, from 2000 to 2013. The method starts with land classification based on the environmental factors presumed to control (NPP) to group pixels having similar potential NPP. Then, satellite remotely sensing data were used to compare actual NPP with its potential. The difference in units of mass of carbon and percentage loss were the measure of degradation. The entire BDT (7.45 × 106 km2) was investigated at a spatial resolution of 250 × 250 m. The average annual reduction in NPP due to anthropogenic land degradation in the entire BDT was -2.14 MgC m-2 yr-1, or 17 % of the non-degraded potential, and the total reduction was -214 MgC yr-1. Extreme average annual losses of 524.8 gC m-2 yr-1 were detected. Approximately 20 % of the BDT was classified as "degraded". Varying severities and rates of degradation were found among the river basins, of which the Belyando and Suttor were highest. Interannual, negative trends in reductions of NPP occurred in 7 % of the entire region, indicating ongoing degradation. There was evidence of areas that were in a permanently degraded condition. The findings provide strong evidence and quantitative data for reductions in NPP related to anthropogenic land degradation in the BDT.

[Effect of climate change on net primary productivity of Korean pine (Pinus koraiensis) at different successional stages of broad-leaved Korean pine forest].

PubMed

Qiu, Yang; Gao, Lu-Shuang; Zhang, Xue; Guo, Jing; Ma, Zhi-Yuan

2014-07-01

Pinus koraiensis in broad-leaved Korean pine forests of Changbai Mountain at different successional stages (secondary poplar-birch forest, secondary coniferous and broad-leaved forest and the primitive Korean pine forest) were selected in this paper as the research objects. In this research, the annual growth of net primary productivity (NPP) (1921-2006) of P. koraiensis was obtained by combining the tree-ring chronology and relative growth formulae, the correlation between NPP of P. koraiensis and climatic factors was developed, and the annual growth of NPP of P. koraiensis at different successional stages in relation to climatic variation within different climate periods were analyzed. The results showed that, in the research period, the correlations between climatic factors and NPP of P. koraiensis at different successional stages were different. With increasing the temperature, the correlations between NPP of P. koraiensis in the secondary poplar-birch forest and the minimum temperatures of previous and current growing seasons changed from being significantly negative to being significantly positive. The positive correlation between NPP of P. koraiensis in the secondary coniferous and broad-leaved forest and the minimum temperature in current spring changed into significantly positive correlation between NPP of P. koraiensis and the temperatures in previous and current growing seasons. The climatic factors had a stronger hysteresis effect on NPP of P. koraiensis in the secondary coniferous and broad-leaved forest, but NPP of P. koraiensis in the primitive Korean pine forest had weaker correlation with temperature but stronger positive correlation with the precipitation of previous growing season. The increases of minimum and mean temperatures were obvious, but no significant variations of the maximum temperature and precipitation were observed at our site. The climatic variation facilitated the increase of the NPP of P. koraiensis in the secondary poplar-birch forest at the initial successional stage and in secondary coniferous and broad-leaved forest at the intermediate successional stage, and this effect was especially obvious for the secondary coniferous and broad-leaved forest, but very small for the primitive Korean pine forest which was at the climax phase.

Predicting the conditions under which vibroacoustic resonances with external periodic loads occur in the primary coolant circuits of VVER-based NPPs

NASA Astrophysics Data System (ADS)

Proskuryakov, K. N.; Fedorov, A. I.; Zaporozhets, M. V.

2015-08-01

The accident at the Japanese Fukushima Daiichi nuclear power plant (NPP) caused by an earthquake showed the need of taking further efforts aimed at improving the design and engineering solutions for ensuring seismic resistance of NPPs with due regard to mutual influence of the dynamic processes occurring in the NPP building structures and process systems. Resonance interaction between the vibrations of NPP equipment and coolant pressure pulsations leads to an abnormal growth of dynamic stresses in structural materials, accelerated exhaustion of equipment service life, and increased number of sudden equipment failures. The article presents the results from a combined calculation-theoretical and experimental substantiation of mutual amplification of two kinds of external periodic loads caused by rotation of the reactor coolant pump (RCP) rotor and an earthquake. The data of vibration measurements at an NPP are presented, which confirm the predicted multiple amplification of vibrations in the steam generator and RCP at a certain combination of coolant thermal-hydraulic parameters. It is shown that the vibration frequencies of the main equipment may fall in the frequency band corresponding to the maximal values in the envelope response spectra constructed on the basis of floor accelerograms. The article presents the results from prediction of conditions under which vibroacoustic resonances with external periodic loads take place, which confirm the occurrence of additional earthquake-induced multiple growth of pressure pulsation intensity in the steam generator at the 8.3 Hz frequency and additional multiple growth of vibrations of the RCP and the steam generator cold header at the 16.6 Hz frequency. It is shown that at the elastic wave frequency equal to 8.3 Hz in the coolant, resonance occurs with the frequency of forced vibrations caused by the rotation of the RCP rotor. A conclusion is drawn about the possibility of exceeding the design level of equipment vibrations under the effect of external periodic loads caused by an earthquake when the vibration frequency of the reactor plant main equipment and the frequency of elastic waves fall in the frequency band corresponding to the maximal values of envelope response spectra.

[Responses of Pinus tabulaeformis forest ecosystem in North China to climate change and elevated CO2: a simulation based on BIOME-BGC model and tree-ring data].

PubMed

He, Jun-Jie; Peng, Xing-Yuan; Chen, Zhen-Ju; Cui, Ming-Xing; Zhang, Xian-Liang; Zhou, Chang-Hong

2012-07-01

Based on BIOME-BGC model and tree-ring data, a modeling study was conducted to estimate the dynamic changes of the net primary productivity (NPP) of Pinus tabulaeformis forest ecosystem in North China in 1952-2008, and explore the responses of the radial growth and NPP to regional climate warming as well as the dynamics of the NPP in the future climate change scenarios. The simulation results indicated the annual NPP of the P. tabulaeformis ecosystem in 1952-2008 fluctuated from 244.12 to 645.31 g C x m(-2) x a(-1), with a mean value of 418.6 g C x m(-2) x a(-1) The mean air temperature in May-June and the precipitation from previous August to current July were the main factors limiting the radial growth of P. tabulaeformis and the NPP of P. tabulaeformis ecosystem. In the study period, both the radial growth and the NPP presented a decreasing trend due to the regional warming and drying climate condition. In the future climate scenarios, the NPP would have positive responses to the increase of air temperature, precipitation, and their combination. The elevated CO2 would benefit the increase of the NPP, and the increment would be about 16.1% due to the CO2 fertilization. At both ecosystem and regional scales, the tree-ring data would be an ideal proxy to predict the ecosystem dynamic change, and could be used to validate and calibrate the process-based ecosystem models including BIOME-BGC.

Grassland Npp Monitoring Based on Multi-Source Remote Sensing Data Fusion

NASA Astrophysics Data System (ADS)

Cai, Y. R.; Zheng, J. H.; Du, M. J.; Mu, C.; Peng, J.

2018-04-01

Vegetation is an important part of the terrestrial ecosystem. It plays an important role in the energy and material exchange of the ground-atmosphere system and is a key part of the global carbon cycle process.Climate change has an important influence on the carbon cycle of terrestrial ecosystems. Net Primary Productivity (Net Primary Productivity)is an important parameter for evaluating global terrestrial ecosystems. For the Xinjiang region, the study of grassland NPP has gradually become a hot issue in the ecological environment.Increasing the estimation accuracy of NPP is of great significance to the development of the ecosystem in Xinjiang. Based on the third-generation GIMMS AVHRR NDVI global vegetation dataset and the MODIS NDVI (MOD13A3) collected each month by the United States Atmospheric and Oceanic Administration (NOAA),combining the advantages of different remotely sensed datasets, this paper obtained the maximum synthesis fusion for New normalized vegetation index (NDVI) time series in 2006-2015.Analysis of Net Primary Productivity of Grassland Vegetation in Xinjiang Using Improved CASA Model The method described in this article proves the feasibility of applying data processing, and the accuracy of the NPP calculation using the fusion processed NDVI has been greatly improved. The results show that: (1) The NPP calculated from the new normalized vegetation index (NDVI) obtained from the fusion of GIMMS AVHRR NDVI and MODIS NDVI is significantly higher than the NPP calculated from these two raw data; (2) The grassland NPP in Xinjiang Interannual changes show an overall increase trend; interannual changes in NPP have a certain relationship with precipitation.

Inferring biome-scale net primary productivity from tree-ring isotopes

NASA Astrophysics Data System (ADS)

Pederson, N.; Levesque, M.; Williams, A. P.; Hobi, M. L.; Smith, W. K.; Andreu-Hayles, L.

2017-12-01

Satellite estimates of vegetation growth (net primary productivity; NPP), tree-ring records, and forest inventories indicate that ongoing climate change and rising atmospheric CO2 concentration are altering productivity and carbon storage of forests worldwide. The impact of global change on the trends of NPP, however, remain unknown because of the lack of long-term high-resolution NPP data. For the first time, we tested if annually resolved carbon (δ13C) and oxygen (δ18O) stable isotopes from the cellulose of tree rings from trees in temperate regions could be used as a tool for inferring NPP across spatiotemporal scales. We compared satellite NPP estimates from the moderate-resolution imaging spectroradiometer sensor (MODIS, product MOD17A) and a newly developed global NPP dataset derived from the Global Inventory Modeling and Mapping Studies (GIMMS) dataset to annually resolved tree-ring width and δ13C and δ18O records from four sites along a hydroclimatic gradient in Eastern and Central United States. We found strong correlations across large geographical regions between satellite-derived NPP and tree-ring isotopes that ranged from -0.40 to -0.91. Notably, tree-ring derived δ18O had the strongest relation to climate. The results were consistent among the studied tree species (Quercus rubra and Liriodendron tulipifera) and along the hydroclimatic conditions of our network. Our study indicates that tree-ring isotopes can potentially be used to reconstruct NPP in time and space. As such, our findings represent an important breakthrough for estimating long-term changes in vegetation productivity at the biome scale.

75 FR 5355 - Notice of Extension of Comment Period for NUREG-1934, Nuclear Power Plant Fire Modeling...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-02-02

..., Nuclear Power Plant Fire Modeling Application Guide (NPP FIRE MAG), Draft Report for Comment AGENCY... 1019195), Nuclear Power Plant Fire Modeling Application Guide (NPP FIRE MAG), Draft Report for Comment... Plant Fire Modeling Application Guide (NPP FIRE MAG)'' is available electronically under ADAMS Accession...

NPP/NPOESS Status

NASA Astrophysics Data System (ADS)

Stockton, D.

2009-12-01

In this presentation, the NPOESS Integrated Program Office will provide a status update on the NPOESS Preparatory Project (NPP) and the NPOESS program. This update will include information on sensors, data products, and the spacecraft as well as the current schedules for NPP and NPOESS. The presentation will also touch on cooperation with EUMETSAT, both current and future.

Channel Nucleoporins Recruit PLK-1 to Nuclear Pore Complexes to Direct Nuclear Envelope Breakdown in C. elegans.

PubMed

Martino, Lisa; Morchoisne-Bolhy, Stéphanie; Cheerambathur, Dhanya K; Van Hove, Lucie; Dumont, Julien; Joly, Nicolas; Desai, Arshad; Doye, Valérie; Pintard, Lionel

2017-10-23

In animal cells, nuclear envelope breakdown (NEBD) is required for proper chromosome segregation. Whereas mitotic kinases have been implicated in NEBD, how they coordinate their activity to trigger this event is unclear. Here, we show that both in human cells and Caenorhabditis elegans, the Polo-like kinase 1 (PLK-1) is recruited to the nuclear pore complexes, just prior to NEBD, through its Polo-box domain (PBD). We provide evidence that PLK-1 localization to the nuclear envelope (NE) is required for efficient NEBD. We identify the central channel nucleoporins NPP-1/Nup58, NPP-4/Nup54, and NPP-11/Nup62 as the critical factors anchoring PLK-1 to the NE in C. elegans. In particular, NPP-1, NPP-4, and NPP-11 primed at multiple Polo-docking sites by Cdk1 and PLK-1 itself physically interact with the PLK-1 PBD. We conclude that nucleoporins play an unanticipated regulatory role in NEBD, by recruiting PLK-1 to the NE thereby facilitating phosphorylation of critical downstream targets. Copyright © 2017 Elsevier Inc. All rights reserved.

Changes in interannual climate sensitivities of terrestrial carbon fluxes during the 21st century predicted by CMIP5 Earth System Models

NASA Astrophysics Data System (ADS)

Liu, Yongwen; Wang, Tao; Huang, Mengtian; Yao, Yitong; Ciais, Philippe; Piao, Shilong

2016-03-01

Terrestrial carbon fluxes are sensitive to climate change, but the interannual climate sensitivity of the land carbon cycle can also change with time. We analyzed the changes in responses of net biome production (NBP), net primary production (NPP), and heterotrophic respiration (Rh) to interannual climate variations over the 21st century in the Earth System Models (ESMs) from the Coupled Model Intercomparison Project 5. Under Representative Concentration Pathway (RCP) 4.5, interannual temperature sensitivities of NBP (γTempNBP), NPP (γTempNPP), and Rh (γTempRh) remain relatively stable at global scale, yet with large differences among ESMs and spatial heterogeneity. Modeled γTempNPP and γTempRh appear to increase in parallel in boreal regions, resulting in unchanged γTempNBP. Tropical γTempNBP decreases in most models, due to decreasing γTempNPP and relatively stable γTempRh. Across models, the changes in γTempNBP can be mainly explained by changes in γTempNPP rather than changes in γTempRh, at both global and regional scales. Interannual precipitation sensitivities of global NBP (γPrecNBP), NPP (γPrecNPP), and Rh (γPrecRh) are predicted not to change significantly, with large differences among ESMs. Across models, the changes in γPrecNBP can be mainly explained by changes in γPrecNPP rather than changes in γPrecRh in temperate regions, but not in other regions. Changes in the interannual climate sensitivities of carbon fluxes are consistent across RCPs 4.5, 6.0, and 8.5 but larger in more intensive scenarios. More effort should be considered to improve terrestrial carbon flux responses to interannual climate variability, e.g., incorporating biogeochemical processes of nutrient limitation, permafrost dynamics, and microbial decomposition.

The Influences of Drought and Land-Cover Conversion on Inter-Annual Variation of NPP in the Three-North Shelterbelt Program Zone of China Based on MODIS Data

PubMed Central

Wu, Chaoyang; Zhang, Bing; Huete, Alfredo; Zhang, Xiaoyang; Sun, Rui; Lei, Liping; Huang, Wenjing; Liu, Liangyun; Liu, Xinjie; Li, Jun; Luo, Shezhou; Fang, Bin

2016-01-01

Terrestrial ecosystems greatly contribute to carbon (C) emission reduction targets through photosynthetic C uptake.Net primary production (NPP) represents the amount of atmospheric C fixed by plants and accumulated as biomass. The Three-North Shelterbelt Program (TNSP) zone accounts for more than 40% of China’s landmass. This zone has been the scene of several large-scale ecological restoration efforts since the late 1990s, and has witnessed significant changes in climate and human activities.Assessing the relative roles of different causal factors on NPP variability in TNSP zone is very important for establishing reasonable local policies to realize the emission reduction targets for central government. In this study, we examined the relative roles of drought and land cover conversion(LCC) on inter-annual changes of TNSP zone for 2001–2010. We applied integrated correlation and decomposition analyses to a Standardized Evapotranspiration Index (SPEI) and MODIS land cover dataset. Our results show that the 10-year average NPP within this region was about 420 Tg C. We found that about 60% of total annual NPP over the study area was significantly correlated with SPEI (p<0.05). The LCC-NPP relationship, which is especially evident for forests in the south-central area, indicates that ecological programs have a positive impact on C sequestration in the TNSP zone. Decomposition analysis generally indicated that the contributions of LCC, drought, and other Natural or Anthropogenic activities (ONA) to changes in NPP generally had a consistent distribution pattern for consecutive years. Drought and ONA contributed about 74% and 23% to the total changes in NPP, respectively, and the remaining 3% was attributed to LCC. Our results highlight the importance of rainfall supply on NPP variability in the TNSP zone. PMID:27348303

Reduction of net primary productivity in southern China caused by abnormal low-temperature freezing in winter of 2008 detected by a remote sensing-driven ecosystem model

NASA Astrophysics Data System (ADS)

Ju, W.; Liu, Y.; Zhou, Y.; Zhu, G.

2011-12-01

Terrestrial carbon cycle is an important determinant of global climate change and affected by various factors, including climate, CO2 concentration, atmospheric nitrogen deposition and human activities. Extreme weather events can significantly regulate short-term even long-term carbon exchanges between terrestrial ecosystems and the atmosphere. During the period from the middle January to the middle February 2008, Southern China was seriously hit by abnormal low-temperature freezing, which caused serous damages to forests and crops. However, the reduction of net primary productivity (NPP) of terrestrial ecosystems caused by this extremely abnormal weather event has not been quantitatively investigated. In this study, the Boreal Ecosystem Productivity Simulator (BEPS) model was employed to assess the reduction of NPP in Southern China caused by the abnormal low-temperature freezing. Prior to the regional simulation, the BEPS model was validated using measured NPP in different ecosystems, demonstrating the ability of this model to simulate NPP reliably in China. Then, it was forced using meteorological data interpolated from observations of weather stations and leaf area index inversed from MODIS reflectance data to simulate national wide NPP at a 500 m resolution for the period from 2003 to 2008. The departures of NPP in 2008 from the means during 2003-2007 were used as the indicator of NPP reduction caused by the low-temperature freezing. It was found out that NPP in 2008 decreased significantly in forests of Southern China, especially in Guangdong, Fujian, Zhejiang, Guangxi, Jiangxi, and Hunan Provinces, in which the low-temperature freeing was more serious. The annul reduction of NPP was above 150 g C/m^2/yr in these areas. Key words: Net Primary Productivity, low-temperature freezing, BEPS model, MODIS Correspondence author: Weimin Ju Email:juweimin@nju.edu.cn

NASA's NPOESS Preparatory Project Science Data Segment: A Framework for Measurement-based Earth Science Data Systems

NASA Technical Reports Server (NTRS)

Schwaller, Mathew R.; Schweiss, Robert J.

2007-01-01

The NPOESS Preparatory Project (NPP) Science Data Segment (SDS) provides a framework for the future of NASA s distributed Earth science data systems. The NPP SDS performs research and data product assessment while using a fully distributed architecture. The components of this architecture are organized around key environmental data disciplines: land, ocean, ozone, atmospheric sounding, and atmospheric composition. The SDS thus establishes a set of concepts and a working prototypes. This paper describes the framework used by the NPP Project as it enabled Measurement-Based Earth Science Data Systems for the assessment of NPP products.

NPP Satellite Launch

NASA Image and Video Library

2011-10-28

NASA Deputy Administrator Lori Garver, left, watches the launch of the National Polar-orbiting Operational Environmental Satellite System Preparatory Project (NPP) at the National Oceanic and Atmospheric Administration (NOAA) Satellite Operations Center on Friday, Oct. 28, 2011 in Suitland, Md. U.S Congresswoman Donna Edwards, D-Md., is seen next to Garver. NPP is a joint venture between NASA and NOAA, and is the nation's newest Earth-observing satellite, which will provide data on climate change science, allow for accurate weather forecasts and advance warning for severe weather. NPP was launched from Vandenberg Air Force Base in California. Photo Credit: (NASA/Carla Cioffi)

NPP Satellite Launch

NASA Image and Video Library

2011-10-28

Dr. Kathy Sullivan, center, Deputy Administrator of the National Oceanic and Atmospheric Administration (NOAA) and former NASA astronaut is interviewed by a local television network at NOAA's Satellite Operations Facility in Suitland, Md. after the successful launch of the National Polar-orbiting Operational Environmental Satellite System Preparatory Project (NPP) on Friday, Oct. 28, 2011. NPP is a joint venture between NASA and NOAA, and is the nation's newest Earth-observing satellite, which will provide data on climate change science, allow for accurate weather forecasts and advance warning for severe weather. NPP was launched from Vandenberg Air Force Base in California. Photo Credit: (NASA/Carla Cioffi)

Carbon allocation to biomass production of leaves, fruits and woody organs at seasonal and annual scale in a deciduous- and evergreen temperate forest

NASA Astrophysics Data System (ADS)

Campioli, M.; Gielen, B.; Granier, A.; Verstraeten, A.; Neirynck, J.; Janssens, I. A.

2010-10-01

Carbon taken up by the forest canopy is allocated to tree organs for biomass production and respiration. Because tree organs have different life span and decomposition rate, the tree C allocation determines the residence time of C in the ecosystem and its C cycling rate. The study of the carbon-use efficiency, or ratio between net primary production (NPP) and gross primary production (GPP), represents a convenient way to analyse the C allocation at the stand level. Previous studies mostly focused on comparison of the annual NPP-GPP ratio among forests of different functional types, biomes and age. In this study, we extend the current knowledge by assessing (i) the annual NPP-GPP ratio and its interannual variability (for five years) for five tree organs (leaves, fruits, branches, stem and coarse roots), and (ii) the seasonal dynamic of NPP-GPP ratio of leaves and stems, for two stands dominated by European beech and Scots pine. The average NPP-GPP ratio for the beech stand (38%) was similar to previous estimates for temperate deciduous forests, whereas the NPP-GPP ratio for the pine stand (17%) is the lowest recorded till now in the literature. The proportion of GPP allocated to leaf NPP was similar for both species, whereas beech allocated a remarkable larger proportion of GPP to wood NPP than pine (29% vs. 6%, respectively). The interannual variability of the NPP-GPP ratio for wood was substantially larger than the interannual variability of the NPP-GPP ratio for leaves, fruits and overall stand and it is likely to be controlled by previous year air temperature (both species), previous year drought intensity (beech) and thinning (pine). Seasonal pattern of NPP-GPP ratio greatly differed between beech and pine, with beech presenting the largest ratio in early season, and pine a more uniform ratio along the season. For beech, NPP-GPP ratio of leaves and stems peaked during the same period in the early season, whereas they peaked in opposite periods of the growing season for pine. Seasonal differences in C allocation are likely due to functional differences between deciduous and evergreen species and temporal variability of the sink strength. The similar GPP and autotrophic respiration between stands and the remarkable larger C allocation to wood at the beech stand indicate that at the beech ecosystem C has a longer residence time than at the pine ecosystem. Further research on belowground production and particularly on fine roots and ectomycorrhizal fungi likely represents the most important step to progress our knowledge on C allocation dynamics.

The role of nutrients, productivity and climate in determining tree fruit production in European forests.

PubMed

Fernández-Martínez, Marcos; Vicca, Sara; Janssens, Ivan A; Espelta, Josep Maria; Peñuelas, Josep

2017-01-01

Fruit production (NPP f ), the amount of photosynthates allocated to reproduction (%GPP f ) and their controls for spatial and species-specific variability (e.g. nutrient availability, climate) have been poorly studied in forest ecosystems. We characterized fruit production and its temporal behaviour for several tree species and resolved the effects of gross primary production (GPP), climate and foliar nutrient concentrations. We used data for litterfall and foliar nutrient concentration from 126 European forests and related them to climatic data. GPP was estimated for each forest using a regression model. Mean NPP f ranged from c. 10 to 40 g C m -2  yr -1 and accounted for 0.5-3% of GPP. Forests with higher GPPs produced larger fruit crops. Foliar zinc (Zn) and phosphorus (P) concentrations were associated positively with NPP f , whereas foliar Zn and potassium (K) were negatively related to its temporal variability. Maximum NPP f and interannual variability of NPP f were higher in Fagaceae than in Pinaceae species. NPP f and %GPP f were similar amongst the studied species despite the different reproductive temporal behaviour of Fagaceae and Pinaceae species. We report that foliar concentrations of P and Zn are associated with %GPP f , NPP f and its temporal behaviour. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

The CAFE model: A net production model for global ocean phytoplankton

NASA Astrophysics Data System (ADS)

Silsbe, Greg M.; Behrenfeld, Michael J.; Halsey, Kimberly H.; Milligan, Allen J.; Westberry, Toby K.

2016-12-01

The Carbon, Absorption, and Fluorescence Euphotic-resolving (CAFE) net primary production model is an adaptable framework for advancing global ocean productivity assessments by exploiting state-of-the-art satellite ocean color analyses and addressing key physiological and ecological attributes of phytoplankton. Here we present the first implementation of the CAFE model that incorporates inherent optical properties derived from ocean color measurements into a mechanistic and accurate model of phytoplankton growth rates (μ) and net phytoplankton production (NPP). The CAFE model calculates NPP as the product of energy absorption (QPAR), and the efficiency (ϕμ) by which absorbed energy is converted into carbon biomass (CPhyto), while μ is calculated as NPP normalized to CPhyto. The CAFE model performance is evaluated alongside 21 other NPP models against a spatially robust and globally representative set of direct NPP measurements. This analysis demonstrates that the CAFE model explains the greatest amount of variance and has the lowest model bias relative to other NPP models analyzed with this data set. Global oceanic NPP from the CAFE model (52 Pg C m-2 yr-1) and mean division rates (0.34 day-1) are derived from climatological satellite data (2002-2014). This manuscript discusses and validates individual CAFE model parameters (e.g., QPAR and ϕμ), provides detailed sensitivity analyses, and compares the CAFE model results and parameterization to other widely cited models.

Bamboo Expansion Alters Ecosystem NPP and N Cycling of Evergreen Broad-leaved Forest in Subtropical China

NASA Astrophysics Data System (ADS)

Lu, H.; Song, Q. N.; Wang, W.

2016-12-01

Background and Aims The bamboo (Phyllostachys pubescens) expansion into adjacent forests is a widespread phenomenon in subtropical region, and it has imposed great effects on the species compositions and community structures of cloned ecosystems. This shift in dominant plant life form, from trees to bamboos, may be accompanied by changes in the productivity, standing accumulation of biomass and nutrients and biogeochemical cycles. Methods We compared the net primary production (NPP) and major pools and fluxes of nitrogen (N) in bamboo-dominant forest (BDF) and neighboring secondary evergreen broadleaved forest (EBF) in South China using the space-for-time substitution method. Results The mean annual NPP of BDF was 30.0 t ha-1 a-1, which was 51.5 % greater than that of the EBF (19.8 t ha-1 a-1), with fine root contributed more than 8.2 kg ha-1. The plant N pool for BDF was 37.5% larger than that of the EBF, because of higher N content in P. pubescens tissues relative to that in trees, whereas the soil inorganic N pool significantly decreased in the EBF by 31.2 % compared with that in the BDF. Additionally, the ratio of N return to N uptake was 0.69 in the BDF and 0.88 in the EBF because of the lower litter N return of the BDF compared with that of the EBF. Conclusion These results indicated that the expansion of P. pubescens significantly increased the NPP and plant N accumulation but reduced the soil N available pool and slowed the N cycling rate, which could lead to soil degradation. These findings have great additional information for the assessment of P. pubescens expansion, and enrich our understanding of bamboo expansion into neighboring forests in subtropical China.

Epitaxial solar-cell fabrication, phase 2

NASA Technical Reports Server (NTRS)

Daiello, R. V.; Robinson, P. H.; Kressel, H.

1977-01-01

Dichlorosilane (SiH2Cl2) was used as the silicon source material in all of the epitaxial growths. Both n/p/p(+) and p/n/n(+) structures were studied. Correlations were made between the measured profiles and the solar cell parameters, especially cell open-circuit voltage. It was found that in order to obtain consistently high open-circuit voltage, the epitaxial techniques used to grow the surface layer must be altered to obtain very abrupt doping profiles in the vicinity of the junction. With these techniques, it was possible to grow reproducibly both p/n/n(+) and n/p/p(+) solar cell structures having open-circuit voltages in the 610- to 630-mV range, with fill-factors in excess of 0.80 and AM-1 efficiencies of about 13%. Combinations and comparisons of epitaxial and diffused surface layers were also made. Using such surface layers, we found that the blue response of epitaxial cells could be improved, resulting in AM-1 short-circuit current densities of about 30 mA/cm sq. The best cells fabricated in this manner had AM-1 efficiency of 14.1%.

Climate change risk to forests in China associated with warming.

PubMed

Yin, Yunhe; Ma, Danyang; Wu, Shaohong

2018-01-11

Variations in forest net primary productivity (NPP) reflects the combined effects of key climate variables on ecosystem structure and function, especially on the carbon cycle. We performed risk analysis indicated by the magnitude of future negative anomalies in NPP in comparison with the natural interannual variability to investigate the impact of future climatic projections on forests in China. Results from the multi-model ensemble showed that climate change risk of decreases in forest NPP would be more significant in higher emission scenario in China. Under relatively low emission scenarios, the total area of risk was predicted to decline, while for RCP8.5, it was predicted to first decrease and then increase after the middle of 21st century. The rapid temperature increases predicted under the RCP8.5 scenario would be probably unfavorable for forest vegetation growth in the long term. High-level risk area was likely to increase except RCP2.6. The percentage area at high risk was predicted to increase from 5.39% (2021-2050) to 27.62% (2071-2099) under RCP8.5. Climate change risk to forests was mostly concentrated in southern subtropical and tropical regions, generally significant under high emission scenario of RCP8.5, which was mainly attributed to the intensified dryness in south China.

Asymmetric warming significantly affects net primary production, but not ecosystem carbon balances of forest and grassland ecosystems in northern China

NASA Astrophysics Data System (ADS)

Su, Hongxin; Feng, Jinchao; Axmacher, Jan C.; Sang, Weiguo

2015-03-01

We combine the process-based ecosystem model (Biome-BGC) with climate change-scenarios based on both RegCM3 model outputs and historic observed trends to quantify differential effects of symmetric and asymmetric warming on ecosystem net primary productivity (NPP), heterotrophic respiration (Rh) and net ecosystem productivity (NEP) of six ecosystem types representing different climatic zones of northern China. Analysis of covariance shows that NPP is significant greater at most ecosystems under the various environmental change scenarios once temperature asymmetries are taken into consideration. However, these differences do not lead to significant differences in NEP, which indicates that asymmetry in climate change does not result in significant alterations of the overall carbon balance in the dominating forest or grassland ecosystems. Overall, NPP, Rh and NEP are regulated by highly interrelated effects of increases in temperature and atmospheric CO2 concentrations and precipitation changes, while the magnitude of these effects strongly varies across the six sites. Further studies underpinned by suitable experiments are nonetheless required to further improve the performance of ecosystem models and confirm the validity of these model predictions. This is crucial for a sound understanding of the mechanisms controlling the variability in asymmetric warming effects on ecosystem structure and functioning.

Asymmetric warming significantly affects net primary production, but not ecosystem carbon balances of forest and grassland ecosystems in northern China.

PubMed

Su, Hongxin; Feng, Jinchao; Axmacher, Jan C; Sang, Weiguo

2015-03-13

We combine the process-based ecosystem model (Biome-BGC) with climate change-scenarios based on both RegCM3 model outputs and historic observed trends to quantify differential effects of symmetric and asymmetric warming on ecosystem net primary productivity (NPP), heterotrophic respiration (Rh) and net ecosystem productivity (NEP) of six ecosystem types representing different climatic zones of northern China. Analysis of covariance shows that NPP is significant greater at most ecosystems under the various environmental change scenarios once temperature asymmetries are taken into consideration. However, these differences do not lead to significant differences in NEP, which indicates that asymmetry in climate change does not result in significant alterations of the overall carbon balance in the dominating forest or grassland ecosystems. Overall, NPP, Rh and NEP are regulated by highly interrelated effects of increases in temperature and atmospheric CO2 concentrations and precipitation changes, while the magnitude of these effects strongly varies across the six sites. Further studies underpinned by suitable experiments are nonetheless required to further improve the performance of ecosystem models and confirm the validity of these model predictions. This is crucial for a sound understanding of the mechanisms controlling the variability in asymmetric warming effects on ecosystem structure and functioning.

Asymmetric warming significantly affects net primary production, but not ecosystem carbon balances of forest and grassland ecosystems in northern China

PubMed Central

Su, Hongxin; Feng, Jinchao; Axmacher, Jan C.; Sang, Weiguo

2015-01-01

We combine the process-based ecosystem model (Biome-BGC) with climate change-scenarios based on both RegCM3 model outputs and historic observed trends to quantify differential effects of symmetric and asymmetric warming on ecosystem net primary productivity (NPP), heterotrophic respiration (Rh) and net ecosystem productivity (NEP) of six ecosystem types representing different climatic zones of northern China. Analysis of covariance shows that NPP is significant greater at most ecosystems under the various environmental change scenarios once temperature asymmetries are taken into consideration. However, these differences do not lead to significant differences in NEP, which indicates that asymmetry in climate change does not result in significant alterations of the overall carbon balance in the dominating forest or grassland ecosystems. Overall, NPP, Rh and NEP are regulated by highly interrelated effects of increases in temperature and atmospheric CO2 concentrations and precipitation changes, while the magnitude of these effects strongly varies across the six sites. Further studies underpinned by suitable experiments are nonetheless required to further improve the performance of ecosystem models and confirm the validity of these model predictions. This is crucial for a sound understanding of the mechanisms controlling the variability in asymmetric warming effects on ecosystem structure and functioning. PMID:25766381

Comparison of Tropical Ozone from SHADOZ with Remote Sensing Retrievals from Suomi-npp Ozone Mapping Profile Suite (OMPS)

NASA Technical Reports Server (NTRS)

Witte, Jacquelyn C.; Thompson, Anne M.; Ziemke, Jerald R.; Wargan, Krzysztof

2014-01-01

The Ozone Mapping Profile Suite (OMPS) was launched October 28, 2011 on-board the Suomi NPP satellite (http://npp.gsfc.nasa.gov). OMPS is the next generation total column ozone mapping instrument for monitoring the global distribution of stratospheric ozone. OMPS includes a limb profiler to measure the vertical structure of stratosphere ozone down to the mid-troposphere. This study uses tropical ozonesonde profile measurements from the Southern Hemisphere Additional Ozonesondes (SHADOZ, http://croc.gsfc.nasa.gov/shadoz) archive to evaluate total column ozone retrievals from OMPS and concurrent measurements from the Aura Ozone Monitoring Instrument (OMI), the predecessor of OMPS with a data record going back to 2004. We include ten SHADOZ stations that contain data overlapping the OMPS time period (2012-2013). This study capitalizes on the ozone profile measurements from SHADOZ to evaluate OMPS limb profile retrievals. Finally, we use SHADOZ sondes and OMPS retrievals to examine the agreement with the GEOS-5 Ozone Assimilation System (GOAS). The GOAS uses data from the OMI and the Microwave Limb Sounder (MLS) to constrain the total column and stratospheric profiles of ozone. The most recent version of the assimilation system is well constrained to the total column compared with SHADOZ ozonesonde data.

Net primary productivity, allocation pattern and carbon use efficiency in an apple orchard assessed by integrating eddy-covariance, biometric and continuous soil chamber measurements

NASA Astrophysics Data System (ADS)

Zanotelli, D.; Montagnani, L.; Manca, G.; Tagliavini, M.

2012-10-01

Carbon use efficiency (CUE) is a functional parameter that could possibly link the current increasingly accurate global estimates of gross primary production with those of net ecosystem exchange, for which global predictors are still unavailable. Nevertheless, CUE estimates are actually available for only a few ecosystem types, while information regarding agro-ecosystems is scarce, in spite of the simplified spatial structure of these ecosystems that facilitates studies on allocation patterns and temporal growth dynamics. We combined three largely deployed methods, eddy covariance, soil respiration and biometric measurements, to assess monthly values of CUE, net primary production (NPP) and allocation patterns in different plant organs in an apple orchard during a complete year (2010). We applied a~measurement protocol optimized for quantifying monthly values of carbon fluxes in this ecosystem type, which allows for a cross-check between estimates obtained from different methods. We also attributed NPP components to standing biomass increments, detritus cycle feeding and lateral exports. We found that in the apple orchard both net ecosystem production and gross primary production on yearly basis, 380 ± 30 g C m-2 and 1263 ± 189 g C m-2 respectively, were of a magnitude comparable to those of natural forests growing in similar climate conditions. The largest differences with respect to forests are in the allocation pattern and in the fate of produced biomass. The carbon sequestered from the atmosphere was largely allocated to production of fruits: 49% of annual NPP was taken away from the ecosystem through apple production. Organic material (leaves, fine root litter, pruned wood and early fruit falls) contributing to the detritus cycle was 46% of the NPP. Only 5% was attributable to standing biomass increment, while this NPP component is generally the largest in forests. The CUE, with an annual average of 0.71 ± 0.09, was higher than the previously suggested constant values of 0.47-0.50. Low nitrogen investment in fruits, the limited root-apparatus, and the optimal growth temperature and nutritional condition observed at the site are suggested to be explanatory variables for the high CUE observed.

Adaptive response of broilers to dietary phosphorus and calcium restrictions.

PubMed

Rousseau, Xavière; Valable, Anne-Sophie; Létourneau-Montminy, Marie-Pierre; Même, Nathalie; Godet, Estelle; Magnin, Michel; Nys, Yves; Duclos, Michel J; Narcy, Agnès

2016-12-01

The aim of this study was to evaluate the capacity of chickens to adapt to and compensate for early dietary restriction of non-phytate P ( NPP: ) and/or Ca (10 to 21 d) in a later phase (22 to 35 d), and to determine whether compensatory processes depend on the P and Ca concentrations in the finisher diet. Four diets were formulated and fed to broilers from 10 to 21 d in order to generate birds with different mineral status: L 1 (0.6% Ca, 0.30% NPP), L 2 (0.6% Ca, 0.45% NPP), H 1 (1.0% Ca, 0.30% NPP), and H 2 (1.0% Ca, 0.45% NPP). On d 22, each group was divided into three groups which received a low (L, 0.48% Ca, 0.24% NPP), moderate (M, 0.70% Ca, 0.35% NPP), or high (H, 0.90% Ca, 0.35% NPP) finisher diet until 35 d, resulting in a total of 12 treatments. Lowering the Ca level enhanced apparent ileal digestibility of P (P AID) at 21 d especially with the high NPP level (Ca × NPP, P < 0.01). The lower bone mineralization observed at 21 d in broilers fed the L 1 diet compared to those fed the H 2 diet had disappeared by 35 d with long-term stimulation of the P AID with the low NPP level (P < 0.001). Although P AID and growth performance were improved in birds fed the L 1 L compared to the L 1 H and H 2 H treatments, tibia characteristics tended to be lower in birds fed the L 1 L compared to those fed the L 1 H treatment. Birds fed the H 1 M treatment had higher P AID, growth performance and tibia ash content than those fed the H 1 H treatment. A significant increase in the mRNA levels of several genes encoding Ca and P transporters was observed at 35 d in birds fed the L 1 followed by the L diet compared to birds fed the L 1 followed by the M diet. In conclusion, chickens are able to adapt to early dietary changes in P and Ca through improvement of digestive efficiency in a later phase, and the extent of the compensation in terms of growth performance and bone mineralization depends on the P and Ca levels in the subsequent diet. © 2016 Poultry Science Association Inc.

Effects of precipitation and clipping intensity on net primary productivity and composition of a Leymus chinensis temperate grassland steppe.

PubMed

He, Feng; Wang, Kun; Hannaway, David B; Li, Xianglin

2017-01-01

Leymus chinensis (Trin.) is the dominant vegetation type in eastern Eurasian temperate grasslands but is decreasing due to the combined pressure of reduced precipitation and overgrazing. This study evaluated the separate and combined effects of precipitation and defoliation on net primary productivity (NPP) and composition of a L. chinensis steppe to promote the sustainable development of temperate grasslands through improved management practices. The effects of three precipitation gradients (precipitation unchanged, reduced by 50%, and increased by 50%) and two clipping intensities (clipping once or twice per year) were examined on NPP and composition of the L. chinensis community using a 7-year in situ controlled trial at the Guyuan State Key Monitoring and Research Station of Grassland Ecosystem in China. The results showed that: (1) a 50% reduction in natural precipitation significantly decreased NPP; a 50% increase in precipitation did not significantly increase NPP, but it decreased the importance value of L. chinensis because more water promoted the growth of competing species. (2) Clipping twice per year increased NPP, but the increase was from the dry matter of other species (DMO) component, and not from the dry matter of L. chinensis. (3) The standardized coefficients of a regression model (β) for DMO, NPP, and the importance value of L. chinensis were 0.685, 0.532, and -0.608 for precipitation, and 0.369, 0.419, and -0.276 for clipping mode, respectively. This study demonstrated that variation in precipitationis the key driver of NPP and composition of a L. chinensis steppe under the precipitation range and clipping intensities evaluated. This improved understanding of the effects of precipitation and clipping on NPP and composition will allow for improved, sustainable management of L. chinensis temperate grassland steppes.

Effects of precipitation and clipping intensity on net primary productivity and composition of a Leymus chinensis temperate grassland steppe

PubMed Central

Wang, Kun; Hannaway, David B.; Li, Xianglin

2017-01-01

Leymus chinensis (Trin.) is the dominant vegetation type in eastern Eurasian temperate grasslands but is decreasing due to the combined pressure of reduced precipitation and overgrazing. This study evaluated the separate and combined effects of precipitation and defoliation on net primary productivity (NPP) and composition of a L. chinensis steppe to promote the sustainable development of temperate grasslands through improved management practices. The effects of three precipitation gradients (precipitation unchanged, reduced by 50%, and increased by 50%) and two clipping intensities (clipping once or twice per year) were examined on NPP and composition of the L. chinensis community using a 7-year in situ controlled trial at the Guyuan State Key Monitoring and Research Station of Grassland Ecosystem in China. The results showed that: (1) a 50% reduction in natural precipitation significantly decreased NPP; a 50% increase in precipitation did not significantly increase NPP, but it decreased the importance value of L. chinensis because more water promoted the growth of competing species. (2) Clipping twice per year increased NPP, but the increase was from the dry matter of other species (DMO) component, and not from the dry matter of L. chinensis. (3) The standardized coefficients of a regression model (β) for DMO, NPP, and the importance value of L. chinensis were 0.685, 0.532, and −0.608 for precipitation, and 0.369, 0.419, and −0.276 for clipping mode, respectively. This study demonstrated that variation in precipitationis the key driver of NPP and composition of a L. chinensis steppe under the precipitation range and clipping intensities evaluated. This improved understanding of the effects of precipitation and clipping on NPP and composition will allow for improved, sustainable management of L. chinensis temperate grassland steppes. PMID:29287115

Performance and bone mineralisation in broiler chicks fed on diets with different concentrations of cholecalciferol at a constant ratio of calcium to non-phytate phosphorus.

PubMed

Rama Rao, S V; Raju, M V L N; Panda, A K; Shyam Sunder, G; Sharma, R P

2009-07-01

1. An experiment was conducted with broiler female chicks (720) to study the effects of graded concentrations (75, 15, 225 or 30 microg/kg) of cholecalciferol (CC) in diets containing varying levels of calcium (Ca) and non-phytate phosphorus (NPP) at a 2:1 ratio (4:2, 5:25, 6:3 or 7:35 g/kg, respectively), on the performance (2-35 d of age), bone mineralisation and mineral (Ca, P, Mn, Fe, Cu) concentration in excreta. 2. Body weight gain, food intake, tibia density and tibia ash increased, and leg abnormality score decreased with dietary increase of CC from 75 to 30 microg at 4 g Ca and 2 g NPP. However, this improvement was not comparable with the birds receiving the highest concentrations of CC, Ca and NPP (30 microg, 7 g and 3.5 g, respectively/kg diet). 3. Significant improvements in the majority of parameters noted with increasing CC up to 225 microg at 5 g Ca and 25 g NPP/kg, which was comparable to those fed the highest levels of CC, Ca and NPP. 4. Concentrations of Ca, P, Mn, Fe and Cu in excreta decreased significantly with increasing CC at all Ca:NPP ratios tested. 5. The predicted requirement of CC for most of the parameters ranged between 1625 and 25 microg/kg diet at 5 g Ca and 25 g NPP. 6. Considering the performance, bone mineralisation, and mineral concentration in excreta, it can be concluded that Ca and NPP levels in broiler diet could be reduced to 5 and 25 g, respectively, while maintaining CC at 25 microg/kg.

KSC-2011-6564

NASA Image and Video Library

2011-07-21

VANDENBERG AIR FORCE BASE, Calif. -- At Vandenberg Air Force Base in California, the interstage of the United Launch Alliance Delta II that will carry NASA's National Polar-orbiting Operational Environmental Satellite System Preparatory Project (NPP) satellite into space is lifted up the side of NASA's Space Launch Complex-2. The interstage provides an interface between the launch vehicle's first and second stages. NPP represents a critical first step in building the next-generation of Earth-observing satellites. NPP will carry the first of the new sensors developed for this satellite fleet, now known as the Joint Polar Satellite System (JPSS) to be launched in 2016. NPP is the bridge between NASA's Earth Observing System (EOS) satellites and the forthcoming series of JPSS satellites. The mission will test key technologies and instruments for the JPSS missions. For more information, visit http://www.nasa.gov/NPP. Photo credit: NASA/VAFB, Rudy Bledsoe

KSC-2011-6563

NASA Image and Video Library

2011-07-21

VANDENBERG AIR FORCE BASE, Calif. -- At Vandenberg Air Force Base in California, the interstage of the United Launch Alliance Delta II that will carry NASA's National Polar-orbiting Operational Environmental Satellite System Preparatory Project (NPP) satellite into space is lifted up the side of NASA's Space Launch Complex-2. The interstage provides an interface between the launch vehicle's first and second stages. NPP represents a critical first step in building the next-generation of Earth-observing satellites. NPP will carry the first of the new sensors developed for this satellite fleet, now known as the Joint Polar Satellite System (JPSS) to be launched in 2016. NPP is the bridge between NASA's Earth Observing System (EOS) satellites and the forthcoming series of JPSS satellites. The mission will test key technologies and instruments for the JPSS missions. For more information, visit http://www.nasa.gov/NPP. Photo credit: NASA/VAFB, Rudy Bledsoe

KSC-2011-6560

NASA Image and Video Library

2011-07-21

VANDENBERG AIR FORCE BASE, Calif. -- At NASA's Space Launch Complex-2 on Vandenberg Air Force Base in California, spacecraft technicians prepare to attach the interstage of the United Launch Alliance Delta II that will carry NASA's National Polar-orbiting Operational Environmental Satellite System Preparatory Project (NPP) satellite into space to a lifting device. The interstage provides an interface between the launch vehicle's first and second stages. NPP represents a critical first step in building the next-generation of Earth-observing satellites. NPP will carry the first of the new sensors developed for this satellite fleet, now known as the Joint Polar Satellite System (JPSS) to be launched in 2016. NPP is the bridge between NASA's Earth Observing System (EOS) satellites and the forthcoming series of JPSS satellites. The mission will test key technologies and instruments for the JPSS missions. For more information, visit http://www.nasa.gov/NPP. Photo credit: NASA/VAFB, Rudy Bledsoe

KSC-2011-6558

NASA Image and Video Library

2011-07-21

VANDENBERG AIR FORCE BASE, Calif. -- At Vandenberg Air Force Base in California, preparations are under way to lift the interstage of the United Launch Alliance Delta II that will carry NASA's National Polar-orbiting Operational Environmental Satellite System Preparatory Project (NPP) satellite into space at NASA's Space Launch Complex-2. The interstage provides an interface between the launch vehicle's first and second stages. NPP represents a critical first step in building the next-generation of Earth-observing satellites. NPP will carry the first of the new sensors developed for this satellite fleet, now known as the Joint Polar Satellite System (JPSS) to be launched in 2016. NPP is the bridge between NASA's Earth Observing System (EOS) satellites and the forthcoming series of JPSS satellites. The mission will test key technologies and instruments for the JPSS missions. For more information, visit http://www.nasa.gov/NPP. Photo credit: NASA/VAFB, Rudy Bledsoe

A probabilistic seismic risk assessment procedure for nuclear power plants: (II) Application

USGS Publications Warehouse

Huang, Y.-N.; Whittaker, A.S.; Luco, N.

2011-01-01

This paper presents the procedures and results of intensity- and time-based seismic risk assessments of a sample nuclear power plant (NPP) to demonstrate the risk-assessment methodology proposed in its companion paper. The intensity-based assessments include three sets of sensitivity studies to identify the impact of the following factors on the seismic vulnerability of the sample NPP, namely: (1) the description of fragility curves for primary and secondary components of NPPs, (2) the number of simulations of NPP response required for risk assessment, and (3) the correlation in responses between NPP components. The time-based assessment is performed as a series of intensity-based assessments. The studies illustrate the utility of the response-based fragility curves and the inclusion of the correlation in the responses of NPP components directly in the risk computation. ?? 2011 Published by Elsevier B.V.

Relationships between net primary productivity and forest stand age in U.S. forests

Treesearch

Liming He; Jing M. Chen; Yude Pan; Richard Birdsey; Jens Kattge

2012-01-01

Net primary productivity (NPP) is a key flux in the terrestrial ecosystem carbon balance, as it summarizes the autotrophic input into the system. Forest NPP varies predictably with stand age, and quantitative information on the NPP-age relationship for different regions and forest types is therefore fundamentally important for forest carbon cycle modeling. We used four...

Synthesis and biological evaluation of novel quinazoline-4-piperidinesulfamide derivatives as inhibitors of NPP1.

PubMed

Forcellini, Elsa; Boutin, Sophie; Lefebvre, Carole-Anne; Shayhidin, Elnur Elyar; Boulanger, Marie-Chloé; Rhéaume, Gabrielle; Barbeau, Xavier; Lagüe, Patrick; Mathieu, Patrick; Paquin, Jean-François

2018-03-10

The ecto-nucleotide pyrophosphatase/phosphodiesterase-1 (NPP1) was recently shown to promote mineralization of the aortic valve, hence, its inhibition represents a significant target. A quinazoline-4-piperidine sulfamide compound (QPS1) has been described as a specific and non-competitive inhibitor of NPP1. We report herein the synthesis and in vitro inhibition studies of novel quinazoline-4-piperidine sulfamide analogues using QPS1 as the lead compound. Of the 26 derivatives prepared, four compounds were found to have K i  < 105 nM against human NPP1. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

Global land-surface primary productivity based upon Nimbus-7 37 GHz data

NASA Technical Reports Server (NTRS)

Choudhury, B. J.

1988-01-01

Accumulation and renewal of organic matter as quantified through net primary productivity (NPP) is considered a very major function of the biosphere, and its estimation is crucial in understanding the carbon cycle. A physically-based model relating NPP to the difference of vertically and horizontally polarized brightness temperatures (Delta T) observed at 37 GHz frequency of the scanning multichannel microwave radiometer on board the Nimbus-7 satellite is used for fitting areally averaged values of NPP and Delta T for five biomes. The land-surface NPP within 80 deg N to 55 deg S is then calculated using the Delta T data and compared with other estimates.

Nonlinear, interacting responses to climate limit grassland production under global change.

PubMed

Zhu, Kai; Chiariello, Nona R; Tobeck, Todd; Fukami, Tadashi; Field, Christopher B

2016-09-20

Global changes in climate, atmospheric composition, and pollutants are altering ecosystems and the goods and services they provide. Among approaches for predicting ecosystem responses, long-term observations and manipulative experiments can be powerful approaches for resolving single-factor and interactive effects of global changes on key metrics such as net primary production (NPP). Here we combine both approaches, developing multidimensional response surfaces for NPP based on the longest-running, best-replicated, most-multifactor global-change experiment at the ecosystem scale-a 17-y study of California grassland exposed to full-factorial warming, added precipitation, elevated CO2, and nitrogen deposition. Single-factor and interactive effects were not time-dependent, enabling us to analyze each year as a separate realization of the experiment and extract NPP as a continuous function of global-change factors. We found a ridge-shaped response surface in which NPP is humped (unimodal) in response to temperature and precipitation when CO2 and nitrogen are ambient, with peak NPP rising under elevated CO2 or nitrogen but also shifting to lower temperatures. Our results suggest that future climate change will push this ecosystem away from conditions that maximize NPP, but with large year-to-year variability.

Responses of Terrestrial Ecosystems’ Net Primary Productivity to Future Regional Climate Change in China

PubMed Central

Zhao, Dongsheng; Wu, Shaohong; Yin, Yunhe

2013-01-01

The impact of regional climate change on net primary productivity (NPP) is an important aspect in the study of ecosystems’ response to global climate change. China’s ecosystems are very sensitive to climate change owing to the influence of the East Asian monsoon. The Lund–Potsdam–Jena Dynamic Global Vegetation Model for China (LPJ-CN), a global dynamical vegetation model developed for China’s terrestrial ecosystems, was applied in this study to simulate the NPP changes affected by future climate change. As the LPJ-CN model is based on natural vegetation, the simulation in this study did not consider the influence of anthropogenic activities. Results suggest that future climate change would have adverse effects on natural ecosystems, with NPP tending to decrease in eastern China, particularly in the temperate and warm temperate regions. NPP would increase in western China, with a concentration in the Tibetan Plateau and the northwest arid regions. The increasing trend in NPP in western China and the decreasing trend in eastern China would be further enhanced by the warming climate. The spatial distribution of NPP, which declines from the southeast coast to the northwest inland, would have minimal variation under scenarios of climate change. PMID:23593325

Responses of terrestrial ecosystems' net primary productivity to future regional climate change in China.

PubMed

Zhao, Dongsheng; Wu, Shaohong; Yin, Yunhe

2013-01-01

The impact of regional climate change on net primary productivity (NPP) is an important aspect in the study of ecosystems' response to global climate change. China's ecosystems are very sensitive to climate change owing to the influence of the East Asian monsoon. The Lund-Potsdam-Jena Dynamic Global Vegetation Model for China (LPJ-CN), a global dynamical vegetation model developed for China's terrestrial ecosystems, was applied in this study to simulate the NPP changes affected by future climate change. As the LPJ-CN model is based on natural vegetation, the simulation in this study did not consider the influence of anthropogenic activities. Results suggest that future climate change would have adverse effects on natural ecosystems, with NPP tending to decrease in eastern China, particularly in the temperate and warm temperate regions. NPP would increase in western China, with a concentration in the Tibetan Plateau and the northwest arid regions. The increasing trend in NPP in western China and the decreasing trend in eastern China would be further enhanced by the warming climate. The spatial distribution of NPP, which declines from the southeast coast to the northwest inland, would have minimal variation under scenarios of climate change.

Estimating Vegetation Primary Production in the Heihe River Basin of China with Multi-Source and Multi-Scale Data.

PubMed

Cui, Tianxiang; Wang, Yujie; Sun, Rui; Qiao, Chen; Fan, Wenjie; Jiang, Guoqing; Hao, Lvyuan; Zhang, Lei

2016-01-01

Estimating gross primary production (GPP) and net primary production (NPP) are significant important in studying carbon cycles. Using models driven by multi-source and multi-scale data is a promising approach to estimate GPP and NPP at regional and global scales. With a focus on data that are openly accessible, this paper presents a GPP and NPP model driven by remotely sensed data and meteorological data with spatial resolutions varying from 30 m to 0.25 degree and temporal resolutions ranging from 3 hours to 1 month, by integrating remote sensing techniques and eco-physiological process theories. Our model is also designed as part of the Multi-source data Synergized Quantitative (MuSyQ) Remote Sensing Production System. In the presented MuSyQ-NPP algorithm, daily GPP for a 10-day period was calculated as a product of incident photosynthetically active radiation (PAR) and its fraction absorbed by vegetation (FPAR) using a light use efficiency (LUE) model. The autotrophic respiration (Ra) was determined using eco-physiological process theories and the daily NPP was obtained as the balance between GPP and Ra. To test its feasibility at regional scales, our model was performed in an arid and semi-arid region of Heihe River Basin, China to generate daily GPP and NPP during the growing season of 2012. The results indicated that both GPP and NPP exhibit clear spatial and temporal patterns in their distribution over Heihe River Basin during the growing season due to the temperature, water and solar influx conditions. After validated against ground-based measurements, MODIS GPP product (MOD17A2H) and results reported in recent literature, we found the MuSyQ-NPP algorithm could yield an RMSE of 2.973 gC m(-2) d(-1) and an R of 0.842 when compared with ground-based GPP while an RMSE of 8.010 gC m(-2) d(-1) and an R of 0.682 can be achieved for MODIS GPP, the estimated NPP values were also well within the range of previous literature, which proved the reliability of our modelling results. This research suggested that the utilization of multi-source data with various scales would help to the establishment of an appropriate model for calculating GPP and NPP at regional scales with relatively high spatial and temporal resolution.

Estimating Vegetation Primary Production in the Heihe River Basin of China with Multi-Source and Multi-Scale Data

PubMed Central

Cui, Tianxiang; Wang, Yujie; Sun, Rui; Qiao, Chen; Fan, Wenjie; Jiang, Guoqing; Hao, Lvyuan; Zhang, Lei

2016-01-01

Estimating gross primary production (GPP) and net primary production (NPP) are significant important in studying carbon cycles. Using models driven by multi-source and multi-scale data is a promising approach to estimate GPP and NPP at regional and global scales. With a focus on data that are openly accessible, this paper presents a GPP and NPP model driven by remotely sensed data and meteorological data with spatial resolutions varying from 30 m to 0.25 degree and temporal resolutions ranging from 3 hours to 1 month, by integrating remote sensing techniques and eco-physiological process theories. Our model is also designed as part of the Multi-source data Synergized Quantitative (MuSyQ) Remote Sensing Production System. In the presented MuSyQ-NPP algorithm, daily GPP for a 10-day period was calculated as a product of incident photosynthetically active radiation (PAR) and its fraction absorbed by vegetation (FPAR) using a light use efficiency (LUE) model. The autotrophic respiration (Ra) was determined using eco-physiological process theories and the daily NPP was obtained as the balance between GPP and Ra. To test its feasibility at regional scales, our model was performed in an arid and semi-arid region of Heihe River Basin, China to generate daily GPP and NPP during the growing season of 2012. The results indicated that both GPP and NPP exhibit clear spatial and temporal patterns in their distribution over Heihe River Basin during the growing season due to the temperature, water and solar influx conditions. After validated against ground-based measurements, MODIS GPP product (MOD17A2H) and results reported in recent literature, we found the MuSyQ-NPP algorithm could yield an RMSE of 2.973 gC m-2 d-1 and an R of 0.842 when compared with ground-based GPP while an RMSE of 8.010 gC m-2 d-1 and an R of 0.682 can be achieved for MODIS GPP, the estimated NPP values were also well within the range of previous literature, which proved the reliability of our modelling results. This research suggested that the utilization of multi-source data with various scales would help to the establishment of an appropriate model for calculating GPP and NPP at regional scales with relatively high spatial and temporal resolution. PMID:27088356

Complex spatiotemporal responses of global terrestrial primary production to climate change and increasing atmospheric CO2 in the 21st century.

PubMed

Pan, Shufen; Tian, Hanqin; Dangal, Shree R S; Zhang, Chi; Yang, Jia; Tao, Bo; Ouyang, Zhiyun; Wang, Xiaoke; Lu, Chaoqun; Ren, Wei; Banger, Kamaljit; Yang, Qichun; Zhang, Bowen; Li, Xia

2014-01-01

Quantitative information on the response of global terrestrial net primary production (NPP) to climate change and increasing atmospheric CO2 is essential for climate change adaptation and mitigation in the 21st century. Using a process-based ecosystem model (the Dynamic Land Ecosystem Model, DLEM), we quantified the magnitude and spatiotemporal variations of contemporary (2000s) global NPP, and projected its potential responses to climate and CO2 changes in the 21st century under the Special Report on Emission Scenarios (SRES) A2 and B1 of Intergovernmental Panel on Climate Change (IPCC). We estimated a global terrestrial NPP of 54.6 (52.8-56.4) PgC yr(-1) as a result of multiple factors during 2000-2009. Climate change would either reduce global NPP (4.6%) under the A2 scenario or slightly enhance NPP (2.2%) under the B1 scenario during 2010-2099. In response to climate change, global NPP would first increase until surface air temperature increases by 1.5 °C (until the 2030s) and then level-off or decline after it increases by more than 1.5 °C (after the 2030s). This result supports the Copenhagen Accord Acknowledgement, which states that staying below 2 °C may not be sufficient and the need to potentially aim for staying below 1.5 °C. The CO2 fertilization effect would result in a 12%-13.9% increase in global NPP during the 21st century. The relative CO2 fertilization effect, i.e. change in NPP on per CO2 (ppm) bases, is projected to first increase quickly then level off in the 2070s and even decline by the end of the 2080s, possibly due to CO2 saturation and nutrient limitation. Terrestrial NPP responses to climate change and elevated atmospheric CO2 largely varied among biomes, with the largest increases in the tundra and boreal needleleaf deciduous forest. Compared to the low emission scenario (B1), the high emission scenario (A2) would lead to larger spatiotemporal variations in NPP, and more dramatic and counteracting impacts from climate and increasing atmospheric CO2.

Complex Spatiotemporal Responses of Global Terrestrial Primary Production to Climate Change and Increasing Atmospheric CO2 in the 21st Century

PubMed Central

Pan, Shufen; Tian, Hanqin; Dangal, Shree R. S.; Zhang, Chi; Yang, Jia; Tao, Bo; Ouyang, Zhiyun; Wang, Xiaoke; Lu, Chaoqun; Ren, Wei; Banger, Kamaljit; Yang, Qichun; Zhang, Bowen; Li, Xia

2014-01-01

Quantitative information on the response of global terrestrial net primary production (NPP) to climate change and increasing atmospheric CO2 is essential for climate change adaptation and mitigation in the 21st century. Using a process-based ecosystem model (the Dynamic Land Ecosystem Model, DLEM), we quantified the magnitude and spatiotemporal variations of contemporary (2000s) global NPP, and projected its potential responses to climate and CO2 changes in the 21st century under the Special Report on Emission Scenarios (SRES) A2 and B1 of Intergovernmental Panel on Climate Change (IPCC). We estimated a global terrestrial NPP of 54.6 (52.8–56.4) PgC yr−1 as a result of multiple factors during 2000–2009. Climate change would either reduce global NPP (4.6%) under the A2 scenario or slightly enhance NPP (2.2%) under the B1 scenario during 2010–2099. In response to climate change, global NPP would first increase until surface air temperature increases by 1.5°C (until the 2030s) and then level-off or decline after it increases by more than 1.5°C (after the 2030s). This result supports the Copenhagen Accord Acknowledgement, which states that staying below 2°C may not be sufficient and the need to potentially aim for staying below 1.5°C. The CO2 fertilization effect would result in a 12%–13.9% increase in global NPP during the 21st century. The relative CO2 fertilization effect, i.e. change in NPP on per CO2 (ppm) bases, is projected to first increase quickly then level off in the 2070s and even decline by the end of the 2080s, possibly due to CO2 saturation and nutrient limitation. Terrestrial NPP responses to climate change and elevated atmospheric CO2 largely varied among biomes, with the largest increases in the tundra and boreal needleleaf deciduous forest. Compared to the low emission scenario (B1), the high emission scenario (A2) would lead to larger spatiotemporal variations in NPP, and more dramatic and counteracting impacts from climate and increasing atmospheric CO2. PMID:25401492

Increased diffuse radiation fraction does not significantly accelerate plant growth

NASA Astrophysics Data System (ADS)

Angert, Alon; Krakauer, Nir

2010-05-01

A recent modelling study (Mercado et al., 2009) claims that increased numbers of scattering aerosols are responsible for a substantial fraction of the terrestrial carbon sink in recent decades because higher diffuse light fraction enhances plant net primary production (NPP). Here we show that observations of atmospheric CO2 seasonal cycle and tree ring data indicate that the relation between diffuse light and NPP is actually quite weak on annual timescales. The inconsistency of these data with the modelling results may arise because the relationships used to quantify the enhancement of NPP were calibrated with eddy covariance measurements of hourly carbon uptake. The effect of diffuse-light fraction on carbon uptake could depend on timescale, since this effect varies rapidly as sun angle and cloudiness change, and since plants can respond dynamically over various timescales to change in incoming radiation. Volcanic eruptions, such as the eruption of Mount Pinatubo in 1991, provide the best available tests for the effect of an annual-scale increase in the diffuse light fraction. Following the Pinatubo Eruption, in 1992 and 1993, a sharp decrease in the atmospheric CO2 growth rate was observed. This could have resulted from enhanced plant carbon uptake. Mercado et al. (2009) argue that largely as a result of the (volcanic aerosol driven) increase in diffuse light fraction, NPP was elevated in 1992, particularly between 25° N-45° N where annual NPP was modelled to be ~0.8 PgC (~10%) above average. In a previous study (Angert et al., 2004) a biogeochemical model (CASA) linked to an atmospheric tracer model (MATCH), was used to show that a diffuse-radiation driven increase in NPP in the extratropics will enhance carbon uptake mostly in summer, leading to a lower CO2 seasonal minimum. Here we use a 'toy model' to show that this conclusion is general and model-independent. The model shows that an enhanced sink of 0.8 PgC, similar to that modelled by Mercado et al. (2009), will result in a measurable decrease (~0.6ppm) in the seasonal CO2 minimum. This holds regardless of whether the sink is the result of 1) An increase in NPP, or 2) The combined effect of a temperature-driven decrease in heterotrophic respiration (Rh) and no change in NPP. This is since both NPP and Rh peak in summer. By contrast, observations from the NOAA global CO2 monitoring network show the opposite change in the seasonal minimum in 1992 and 1993 (~0.2ppm increase) both at Mauna Loa, and in the Marine Boundary Layer mean (>20° N), which is hard to reconcile with increased NPP in northern summer. Another indicator of annual NPP is tree wood increment. Previous work (Krakauer et al., 2003) showed that the average response in tree ring series after past Pinatubo-size volcanic eruptions implied lower NPP north of 45° N, presumably as a result of shorter growing season and lower total irradiance induced by scattering aerosols, and no significant change in NPP at lower latitudes. Here we show that In 1992, after the Pinatubo eruption, ring width in the 25° N-45° N band was 99.3±2.9% of average (n=351 sites), similar to the average of 100.4±2.2% over past eruptions (n=15 eruptions) (Uncertainty is given as 2 SE.). These results are also inconsistent with substantial NPP enhancement, although a limitation of the tree-ring approach is that available measurements do not uniformly sample the latitude band. The combined evidence of tree rings and the CO2 seasonal cycle shows that the enhancement of NPP by scattering aerosols on annual timescales is weak. This result suggests that reducing aerosols through stricter pollution controls may strengthen the land carbon sink, while geo-engineering schemes which aim to mitigate global warming by spreading scattering aerosols in the stratosphere may weaken it.

The NPOESS Preparatory Project Science Data Segment: Brief Overview

NASA Technical Reports Server (NTRS)

Schweiss, Robert J.; Ho, Evelyn; Ullman, Richard; Samadi, Shahin

2006-01-01

The NPOESS Preparatory Project (NPP) provides remotely-sensed land, ocean, atmospheric, ozone, and sounder data that will serve the meteorological and global climate change scientific communities while also providing risk reduction for the National Polar-orbiting Operational Environmental Satellite System (NPOESS), the U.S. Government s future low-Earth orbiting satellite system monitoring global weather and environmental conditions. NPOESS and NPP are a new era, not only because the sensors will provide unprecedented quality and volume of data but also because it is a joint mission of three federal agencies, NASA, NOAA, and DoD. NASA's primary science role in NPP is to independently assess the quality of the NPP science and environmental data records. Such assessment is critical for making NPOESS products the best that they can be for operational use and ultimately for climate studies. The Science Data Segment (SDS) supports science assessment by assuring the timely provision of NPP data to NASA s science teams organized by climate measurement themes. The SDS breaks down into nine major elements, an input element that receives data from the operational agencies and acts as a buffer, a calibration analysis element, five elements devoted to measurement based quality assessment, an element used to test algorithmic improvements, and an element that provides overall science direction. This paper will describe how the NPP SDS will leverage on NASA experience to provide a mission-reliable research capability for science assessment of NPP derived measurements.

Circumpolar arctic tundra biomass and productivity dynamics in response to projected climate change and herbivory.

PubMed

Yu, Qin; Epstein, Howard; Engstrom, Ryan; Walker, Donald

2017-09-01

Satellite remote sensing data have indicated a general 'greening' trend in the arctic tundra biome. However, the observed changes based on remote sensing are the result of multiple environmental drivers, and the effects of individual controls such as warming, herbivory, and other disturbances on changes in vegetation biomass, community structure, and ecosystem function remain unclear. We apply ArcVeg, an arctic tundra vegetation dynamics model, to estimate potential changes in vegetation biomass and net primary production (NPP) at the plant community and functional type levels. ArcVeg is driven by soil nitrogen output from the Terrestrial Ecosystem Model, existing densities of Rangifer populations, and projected summer temperature changes by the NCAR CCSM4.0 general circulation model across the Arctic. We quantified the changes in aboveground biomass and NPP resulting from (i) observed herbivory only; (ii) projected climate change only; and (iii) coupled effects of projected climate change and herbivory. We evaluated model outputs of the absolute and relative differences in biomass and NPP by country, bioclimate subzone, and floristic province. Estimated potential biomass increases resulting from temperature increase only are approximately 5% greater than the biomass modeled due to coupled warming and herbivory. Such potential increases are greater in areas currently occupied by large or dense Rangifer herds such as the Nenets-occupied regions in Russia (27% greater vegetation increase without herbivores). In addition, herbivory modulates shifts in plant community structure caused by warming. Plant functional types such as shrubs and mosses were affected to a greater degree than other functional types by either warming or herbivory or coupled effects of the two. © 2017 John Wiley & Sons Ltd.

Modeling of Carbon Sequestration on Eucalyptus Plantation in Brazililian Cerrado Region for Better Characterization of Net Primary Productivity

NASA Astrophysics Data System (ADS)

Echeverri, J. D.; Siqueira, M. B.

2013-05-01

Managed Forests have important roles in climate change due to their contribution to CO2 sequestration stored in their biomass, soils and products therefrom. Terrestrial net primary production (NPP, kgC/m2), equal to gross primary production minus autotrophic respiration, represents the carbon available for plant allocation to leaves, stems, roots, defensive compounds, and reproduction and is the basic measure of biological productivity. Tree growth, food production, fossil fuel production, and atmospheric CO2 levels are all strongly controlled by NPP. Accurate quantification of NPP at local to global scales is therefore central topic for carbon cycle researchers, foresters, land and resource managers, and politicians. For recent or current NPP estimates, satellite remote sensing can be used but for future climate scenarios, simulation models are required. There is an increasing trend to displace natural Brazilian Cerrado to Eucalyptus for paper mills and energy conversion from biomass. The objective of this research exercise is to characterize NPP from managed Eucalyptus plantation in the Brazilian Cerrado. The models selected for this study were the 3-PG and Biome-BGC. The selection of these models aims to cover a range of complexity that allow the evaluation of the processes modeled as to its relevance to a best estimate of productivity in eucalyptus forests. 3-PG model is the simplest of the models chosen for this exercise. Its main purpose is to estimate productivity of forests in timber production. The model uses the relationship of quantum efficiency in the transformation of light energy into biomass for vegetative growth calculations in steps in time of one month. Adverse weather conditions are treated with reduction factors applied in the top efficiency. The second model is the Biome-BGC that uses biology and geochemistry principles to estimate leaf-level photosynthesis based on limiting factors such as availability of light and nutrient constraints. The model does not consider any vertical structure, and the extrapolation of leaf scale is the scale of the ecosystem, which is accomplished by using leaf area index to variable on a temporal resolution of a day. Carbon allocation is computed by complex interactions between multiples carbon pools. Therefore the results obtained in modeling, it was possible to verify the applicability of the two models 3PG and Biome-BGC in estimate of NPP to eucalyptus energy forest in a Brazilian cerrado region, having a strong correlation to the sixth year of forest growth between the two models. The study also revealed that have input parameters in models that need to be measured with a good accuracy, because in function of these parameters, the NPP variation is very large. Finally the study revealed the importance of confronting the data obtained by 3PG and Biome-BGC with experimental data to improve performance modeled-based estimation.

Prolonged elevated body mass index in preschool children after the Great East Japan Earthquake.

PubMed

Isojima, Tsuyoshi; Yokoya, Susumu; Ono, Atsushi; Kato, Noriko; Tanaka, Toshiaki; Yokomichi, Hiroshi; Yamagata, Zentaro; Tanaka, Soichiro; Matsubara, Hiroko; Ishikuro, Mami; Kikuya, Masahiro; Chida, Shoichi; Hosoya, Mitsuaki; Kuriyama, Shinichi; Kure, Shigeo

2017-09-01

The Great East Japan Earthquake followed by tsunamis and the Fukushima Daiichi Nuclear Power Plant (NPP) accident caused catastrophic damage. The effects of the disaster on the growth of affected children are of great concern but remain unknown. The subject group was derived from two Japanese nationwide retrospective cohorts (historical control and exposure groups, respectively). The exposure group experienced the disaster at 47-59 months of age. We analyzed longitudinal changes in standard deviation score (SDS) for height and body mass index (BMI) using normal Japanese children's standards. Moreover, we analyzed the details of the affected children in Fukushima using Fukushima-specific growth charts established with the historical control data to clarify any indirect effect of the disaster on growth. Affected children in Fukushima had significantly higher BMI SDS than the historical control group (difference, 0.13; 95% CI: 0.044-0.21, P = 0.0029) and the regional controls (difference, 0.14; 95% CI: 0.074-0.20, P < 0.0001) 1.5 years after the disaster. Similar sustained increases in BMI SDS were also found with Fukushima-specific growth charts, but the phenomenon was detected only in boys. Notably, the BMI SDS of affected children who lived near the NPP had been increasing after the disaster, whereas those in distant areas had not changed. In contrast, height SDS had not changed throughout the analysis. Prolonged elevated BMI SDS was detected only in affected children in Fukushima. This phenomenon may be explained by an indirect effect of the NPP accident. © 2017 Japan Pediatric Society.

The ratio of NPP to GPP: evidence of change over the course of stand development

Treesearch

Annikki Makela; Harry T. Valentine

2001-01-01

Using Scots pine (Pinus sylvestris L.) in Fenno-Scandia as a case study, we investigate whether net primary production (NPP) and maintenance respiration are constant fractions of gross primary production (GPP) as even-aged mono-specific stands progress from initiation to old age. A model of the ratio of NPP to GPP is developed based on (1) the...

Environmental problems associated with decommissioning the Chernobyl Nuclear Power Plant Cooling Pond.

PubMed

Oskolkov, B Ya; Bondarkov, M D; Gaschak, S P; Maksymenko, A M; Maksymenko, V M; Martynenko, V I; Farfán, E B; Jannik, G T; Marra, J C

2010-11-01

Decommissioning of nuclear power plants and other nuclear fuel cycle facilities associated with residual radioactive contamination of their territories is an imperative issue. Significant problems may result from decommissioning of cooling ponds with residual radioactive contamination. The Chernobyl Nuclear Power Plant (ChNPP) Cooling Pond is one of the largest self-contained water reservoirs in the Chernobyl region and Ukrainian and Belorussian Polesye region. The 1986 ChNPP Reactor Unit Number Four significantly contaminated the ChNPP Cooling Pond. The total radionuclide inventory in the ChNPP Cooling Pond bottom deposits are as follows: ¹³⁷Cs: 16.28 ± 2.59 TBq; ⁹⁰Sr: 2.4 ± 0.48 TBq; and ²³⁹+²⁴⁰Pu: 0.00518 ± 0.00148 TBq. The ChNPP Cooling Pond is inhabited by over 500 algae species and subspecies, over 200 invertebrate species, and 36 fish species. The total mass of the living organisms in the ChNPP Cooling Pond is estimated to range from about 60,000 to 100,000 tons. The territory adjacent to the ChNPP Cooling Pond attracts many birds and mammals (178 bird species and 47 mammal species were recorded in the Chernobyl Exclusion Zone). This article describes several options for the ChNPP Cooling Pond decommissioning and environmental problems associated with its decommissioning. The article also provides assessments of the existing and potential exposure doses for the shoreline biota. For the 2008 conditions, the estimated total dose rate values were 11.4 40 μGy h⁻¹ for amphibians, 6.3 μGy h⁻¹ for birds, 15.1 μGy h⁻¹ for mammals, and 10.3 μGy h⁻¹ for reptiles, with the recommended maximum dose rate being equal to 40 μGy h⁻¹. However, drying the ChNPP Cooling Pond may increase the exposure doses to 94.5 μGy h⁻¹ for amphibians, 95.2 μGy h⁻¹ for birds, 284.0 μGy h⁻¹ for mammals, and 847.0 μGy h⁻¹ for reptiles. All of these anticipated dose rates exceed the recommended values.

Dietary non-phytate phosphorus requirement of broilers fed a conventional corn-soybean meal diet from 1 to 21 d of age.

PubMed

Liu, S B; Liao, X D; Lu, L; Li, S F; Wang, L; Zhang, L Y; Jiang, Y; Luo, X G

2017-01-01

An experiment was conducted to investigate the effect of dietary non-phytate phosphorus (NPP) level on growth performance, bone characteristics and phosphorus metabolism-related gene expressions, so as to evaluate the dietary NPP requirement of broiler chicks fed a conventional corn-soybean meal diet from 1 to 21 d of age. A total of 540 day-old Arbor Acres male chicks were randomly allocated to one of nine treatments with six replicate cages of 10 birds per cage in a completely randomized design, and fed a basal corn-soybean meal diet (containing 0.08% of NPP) supplemented with 0.10, 0.15, 0.25, 0.30, 0.35, 0.40, 0.45, or 0.50% of inorganic phosphorus in the form of CaHPO 4 ·2H 2 O, respectively. Each diet contained the constant calcium content of about 1.0%. The results showed that daily weight gain, serum inorganic P, tibia bone strength, tibia ash percentage, tibia bone mineral content (BMC) and density (BMD), middle toe ash percentage, middle toe BMC and BMD were affected (P < 0.0001) by dietary NPP level, and increased linearly (P < 0.0001) and quadraticly (P < 0.004) as dietary NPP levels increased. The gene expression of type IIb sodium-phosphate cotransporter (NaPi-IIb) in the duodenum was affected (P < 0.03) and decreased linearly (P < 0.002) as dietary NPP levels increased. Dietary NPP requirements estimated based on fitted broken-line models (P < 0.0001) of the sensitive indices including daily weight gain, tibia bone strength, tibia ash percentage, tibia BMC and BMD as well as middle toe ash percentage were 0.34∼0.39%. The results from this study indicate that tibia BMC and BMD might be new, sensitive, and noninvasive criteria to evaluate the dietary NPP requirements of broilers, and the dietary NPP requirement is 0.39% for broiler chicks fed a conventional corn-soybean meal diet from 1 to 21 d of age. © 2016 Poultry Science Association Inc.

Quantifying the effect of trend, fluctuation, and extreme event of climate change on ecosystem productivity.

PubMed

Liu, Yupeng; Yu, Deyong; Su, Yun; Hao, Ruifang

2014-12-01

Climate change comprises three fractions of trend, fluctuation, and extreme event. Assessing the effect of climate change on terrestrial ecosystem requires an understanding of the action mechanism of these fractions, respectively. This study examined 11 years of remotely sensed-derived net primary productivity (NPP) to identify the impacts of the trend and fluctuation of climate change as well as extremely low temperatures caused by a freezing disaster on ecosystem productivity in Hunan province, China. The partial least squares regression model was used to evaluate the contributions of temperature, precipitation, and photosynthetically active radiation (PAR) to NPP variation. A climatic signal decomposition and contribution assessment model was proposed to decompose climate factors into trend and fluctuation components. Then, we quantitatively evaluated the contributions of each component of climatic factors to NPP variation. The results indicated that the total contribution of the temperature, precipitation, and PAR to NPP variation from 2001 to 2011 in Hunan province is 85 %, and individual contributions of the temperature, precipitation, and PAR to NPP variation are 44 % (including 34 % trend contribution and 10 % fluctuation contribution), 5 % (including 4 % trend contribution and 1 % fluctuation contribution), and 36 % (including 30 % trend contribution and 6 % fluctuation contribution), respectively. The contributions of temperature fluctuation-driven NPP were higher in the north and lower in the south, and the contributions of precipitation trend-driven NPP and PAR fluctuation-driven NPP are higher in the west and lower in the east. As an instance of occasionally triggered disturbance in 2008, extremely low temperatures and a freezing disaster produced an abrupt decrease of NPP in forest and grass ecosystems. These results prove that the climatic trend change brought about great impacts on ecosystem productivity and that climatic fluctuations and extreme events can also alter the ecosystem succession process, even resulting in an alternative trajectory. All of these findings could improve our understanding of the impacts of climate change on the provision of ecosystem functions and services and can also provide a basis for policy makers to apply adaptive measures to overcome the unfavorable influence of climate change.

Human-Induced Vegetation Degradation in a Semi-Arid Rangeland

NASA Astrophysics Data System (ADS)

Jackson, Hasan

Current assessments of anthropogenic land degradation and its impact on vegetation at regional scales are prone to large uncertainties due to the lack of an objective, transferable, spatially and temporally explicit measure of land degradation. These uncertainties have resulted in contradictory estimates of degradation extent and severity and the role of human activities. The uncertainties limit the ability to assess the effects on the biophysical environment and effectiveness of past, current, and future policies of land use. The overall objective of the dissertation is to assess degradation in a semi-arid region at a regional scale where the process of anthropogenic land degradation is evident. Net primary productivity (NPP) is used as the primary indicator to measure degradation. It is hypothesized that land degradation resulting from human factors on the landscape irreversibly reduces NPP below the potential set by environmental conditions. It is also hypothesized that resulting reductions in NPP are distinguishable from natural, spatial and temporal, variability in NPP. The specific goals of the dissertation are to (1) identify the extent and severity of degradation using productivity as the primary surrogate, (2) compare the degradation of productivity to other known mechanisms of degradation, and (3) relate the expression of degradation to components of vegetation and varying environmental conditions. This dissertation employed the Local NPP Scaling (LNS) approach to identify patterns of anthropogenic degradation of NPP in the Burdekin Dry Tropics (BDT) region of Queensland (14 million hectares), Australia from 2000 to 2013. The method started with land classification based on the environmental factors presumed to control NPP to group pixels having similar potential NPP. Then, satellite remotely sensing data were used to compare actual NPP with its potential. The difference, in units of mass of carbon fixed in NPP per unit area per monitoring interval and per year, also its percentage of the potential, were the measures of degradation. Degradation was then compared to non-green components of vegetation (e.g. wood, stems, leaf litter, dead biomass) to determine their relationship in space and time. Finally, the symptoms of degradation were compared to land management patterns and the environmental variability (e.g. drought, non-drought conditions). Nearly 20% of the region was identified as degraded and another 7% had significant negative trends. The average annual reduction in NPP due to anthropogenic degradation was -17% of the non-degraded potential, although the severity of degradation varied substantially throughout the region. Non-green vegetation cover was strongly correlated with the inter-annual and intra-annual temporal trends of degradation. The dynamics of degradation in drought and non-drought years provided evidence of multiple stables states of degradation.

How does trust affect acceptance of a nuclear power plant (NPP): A survey among people living with Qinshan NPP in China

PubMed Central

Feldman, Marcus W.

2017-01-01

It is difficult to know whether different dimensions of trust have different effects on local residents’ acceptance of nuclear power plants (NPPs). In previous research such trust has been considered as a single dimensional concept. This paper divides trust into goodwill trust and competence trust, and we explore the ways in which trust affects acceptance of NPPs through structural equation modeling. A survey of 491 people was conducted in Haiyan County, China, where the Qinshan nuclear power plant is located. We find that goodwill trust is significantly correlated with competence trust, and each can indirectly promote residents’ acceptance of NPPs but by different paths. Goodwill trust improves acceptance of NPPs by decreasing risk perception, while competence trust improves acceptance of NPPs by increasing benefit perception. However, the associations between goodwill trust and benefit perception, competence trust and risk perception, are not significant. PMID:29176852

How does trust affect acceptance of a nuclear power plant (NPP): A survey among people living with Qinshan NPP in China.

PubMed

Xiao, Qunying; Liu, Huijun; Feldman, Marcus W

2017-01-01

It is difficult to know whether different dimensions of trust have different effects on local residents' acceptance of nuclear power plants (NPPs). In previous research such trust has been considered as a single dimensional concept. This paper divides trust into goodwill trust and competence trust, and we explore the ways in which trust affects acceptance of NPPs through structural equation modeling. A survey of 491 people was conducted in Haiyan County, China, where the Qinshan nuclear power plant is located. We find that goodwill trust is significantly correlated with competence trust, and each can indirectly promote residents' acceptance of NPPs but by different paths. Goodwill trust improves acceptance of NPPs by decreasing risk perception, while competence trust improves acceptance of NPPs by increasing benefit perception. However, the associations between goodwill trust and benefit perception, competence trust and risk perception, are not significant.

Developing Land Surface Type Map with Biome Classification Scheme Using Suomi NPP/JPSS VIIRS Data

NASA Astrophysics Data System (ADS)

Zhang, Rui; Huang, Chengquan; Zhan, Xiwu; Jin, Huiran

2016-08-01

Accurate representation of actual terrestrial surface types at regional to global scales is an important element for a wide range of applications, such as land surface parameterization, modeling of biogeochemical cycles, and carbon cycle studies. In this study, in order to meet the requirement of the retrieval of global leaf area index (LAI) and fraction of photosynthetically active radiation absorbed by the vegetation (fPAR) and other studies, a global map generated from Suomi National Polar- orbiting Partnership (S-NPP) Visible Infrared Imaging Radiometer Suite (VIIRS) surface reflectance data in six major biome classes based on their canopy structures, which include: Grass/Cereal Crops, Shrubs, Broadleaf Crops, Savannas, Broadleaf Forests, and Needleleaf Forests, was created. The primary biome classes were converted from an International Geosphere-Biosphere Program (IGBP) legend global surface type data that was created in previous study, and the separation of two crop types are based on a secondary classification.

Morphological defects in native Japanese fir trees around the Fukushima Daiichi Nuclear Power Plant

PubMed Central

Watanabe, Yoshito; Ichikawa, San’ei; Kubota, Masahide; Hoshino, Junko; Kubota, Yoshihisa; Maruyama, Kouichi; Fuma, Shoichi; Kawaguchi, Isao; Yoschenko, Vasyl I.; Yoshida, Satoshi

2015-01-01

After the accident at the Fukushima Daiichi Nuclear Power Plant (F1NPP) in March 2011, much attention has been paid to the biological consequences of the released radionuclides into the surrounding area. We investigated the morphological changes in Japanese fir, a Japanese endemic native conifer, at locations near the F1NPP. Japanese fir populations near the F1NPP showed a significantly increased number of morphological defects, involving deletions of leader shoots of the main axis, compared to a control population far from the F1NPP. The frequency of the defects corresponded to the radioactive contamination levels of the observation sites. A significant increase in deletions of the leader shoots became apparent in those that elongated after the spring of 2012, a year after the accident. These results suggest possibility that the contamination by radionuclides contributed to the morphological defects in Japanese fir trees in the area near the F1NPP. PMID:26314382

Inter-annual variability and spatial coherence of net primary productivity across a western Oregon Cascades landscape

Treesearch

Travis J. Woolley; Mark E. Harmon; Kari B. O’Connell

2015-01-01

Inter-annual variability (IAV) of forest Net Primary Productivity (NPP) is a function of both extrinsic (e.g., climate) and intrinsic (e.g., stand dynamics) drivers. As estimates of NPP in forests are scaled from trees to stands to the landscape, an understanding of the relative effects of these factors on spatial and temporal behavior of NPP is important. Although a...

Analysis of the Relationship Between Climate and NDVI Variability at Global Scales

NASA Technical Reports Server (NTRS)

Zeng, Fan-Wei; Collatz, G. James; Pinzon, Jorge; Ivanoff, Alvaro

2011-01-01

interannual variability in modeled (CASA) C flux is in part caused by interannual variability in Normalized Difference Vegetation Index (NDVI) Fraction of Photosynthetically Active Radiation (FPAR). This study confirms a mechanism producing variability in modeled NPP: -- NDVI (FPAR) interannual variability is strongly driven by climate; -- The climate driven variability in NDVI (FPAR) can lead to much larger fluctuation in NPP vs. the NPP computed from FPAR climatology

Characterizing uncertainties in recent trends of global terrestrial net primary production through ensemble modeling

NASA Astrophysics Data System (ADS)

Wang, W.; Hashimoto, H.; Ganguly, S.; Votava, P.; Nemani, R. R.; Myneni, R. B.

2010-12-01

Large uncertainties exist in our understanding of the trends and variability in global net primary production (NPP) and its controls. This study attempts to address this question through a multi-model ensemble experiment. In particular, we drive ecosystem models including CASA, LPJ, Biome-BGC, TOPS-BGC, and BEAMS with a long-term climate dataset (i.e., CRU-NCEP) to estimate global NPP from 1901 to 2009 at a spatial resolution of 0.5 x 0.5 degree. We calculate the trends of simulated NPP during different time periods and test their sensitivities to climate variables of solar radiation, air temperature, precipitation, vapor pressure deficit (VPD), and atmospheric CO2 levels. The results indicate a large diversity among the simulated NPP trends over the past 50 years, ranging from nearly no trend to an increasing trend of ~0.1 PgC/yr. Spatial patterns of the NPP generally show positive trends in boreal forests, induced mainly by increasing temperatures in these regions; they also show negative trends in the tropics, although the spatial patterns are more diverse. These diverse trends result from different climatic sensitivities of NPP among the tested models. Depending the ecological processes (e.g., photosynthesis or respiration) a model emphasizes, it can be more or less responsive to changes in solar radiation, temperatures, water, or atmospheric CO2 levels. Overall, these results highlight the limit of current ecosystem models in simulating NPP, which cannot be easily observed. They suggest that the traditional single-model approach is not ideal for characterizing trends and variability in global carbon cycling.

Metabolic rate and environmental productivity: Well-provisioned animals evolved to run and idle fast

PubMed Central

Mueller, Pamela; Diamond, Jared

2001-01-01

Even among vertebrate species of the same body mass and higher-level taxonomic group, metabolic rates exhibit substantial differences, for which diverse explanatory factors—such as dietary energy content, latitude, altitude, temperature, and rainfall—have been postulated. A unifying underlying factor could be food availability, in turn controlled by net primary productivity (NPP) of the animal's natural environment. We tested this possibility by studying five North American species of Peromyscus mice, all of them similar in diet (generalist omnivores) and in gut morphology but differing by factors of up to 13 in NPP of their habitat of origin. We maintained breeding colonies of all five species in the laboratory under identical conditions and consuming identical diets. Basal metabolic rate (BMR) and daily ad libitum food intake both increased with NPP, which explained 88% and 90% of their variances, respectively. High-metabolism mouse species from high-NPP environments were behaviorally more active than were low-metabolism species from low-NPP environments. Intestinal glucose uptake capacity also increased with NPP (and with BMR and food intake), because species of high-NPP environments had larger small intestines and higher uptake rates. For metabolic rates of our five species, the driving environmental variable is environmental productivity itself (and hence food availability), rather than temporal variability of productivity. Thus, species that have evolved in the presence of abundant food run their metabolism “fast,” both while active and while idling, as compared with species of less productive environments, even when all species are given access to unlimited food. PMID:11606744

Grassland Production Change Due Comparison of NPP Estimates by Theoretical Model and Satellite Data from MODIS

NASA Astrophysics Data System (ADS)

Campbell, E. E.; Oliveira, J. D. C.; Lamparelli, R.; Soares, J.; Monteiro, L. A.; Jaiswal, D.; Sheehan, J. J.; Figueiredo, G. K. D. A.; Lynd, L. R.

2017-12-01

Accessing the changes in net primary production (NPP) from grassland in the globe has important applications, e.g. can identify where land have been degraded or in opposite site have been intensified. The aim of this study is to identify the changes occurred in grassland production due management practices and climate change. A recent comparison between a theoretical model of aboveground NPP and satellite data will be performed for the years 2000 to 2003. The theoretical model links NPP to climate, defined as total annual rainfall. Satellite data will use the total annual NPP from MODIS sensor (MOD17A3), that each pixel (spatial resolution of 1 km) include biome type information, daily meteorological data and the fraction absorbed of photosynthetic active radiation (FPAR) and leaf area index (LAI). Both NPP results were set in pastureland that is occupied by ruminants based on year 2000. The correlation between total NPP's values on year 2000 was 0.77. Therefore, the change in the differences between these models can reflect management practices and climate change impacts on grassland biomass production and also the reasonability of using both databases for predicting yield gap. The different from both NPP estimates will be then classified in three groups: no significant difference, significant increase and significant decrease. The outcome results will show the fluctuations in biomass from grassland worldwide. The regions with ongoing pasture degradation will be indentified, and can suggest a need for improvement. In the other hand, pastureland with significant increase in biomass will offer an example of intensification potential. The tendency of the pastureland in each region can give a support for policy makers in order to achieve a sustainability use of the land. Financial Support: FAPESP process 2017/06037-4, 2016/08741-8, 2017/08970-0, 2016/08742-4 and 2014/26767-9

Wave disturbance overwhelms top-down and bottom-up control of primary production in California kelp forests.

PubMed

Reed, Daniel C; Rassweiler, Andrew; Carr, Mark H; Cavanaugh, Kyle C; Malone, Daniel P; Siegel, David A

2011-11-01

We took advantage of regional differences in environmental forcing and consumer abundance to examine the relative importance of nutrient availability (bottom-up), grazing pressure (top-down), and storm waves (disturbance) in determining the standing biomass and net primary production (NPP) of the giant kelp Macrocystis pyrifera in central and southern California. Using a nine-year data set collected from 17 sites we show that, despite high densities of sea urchin grazers and prolonged periods of low nutrient availability in southern California, NPP by giant kelp was twice that of central California where nutrient concentrations were consistently high and sea urchins were nearly absent due to predation by sea otters. Waves associated with winter storms were consistently higher in central California, and the loss of kelp biomass to winter wave disturbance was on average twice that of southern California. These observations suggest that the more intense wave disturbance in central California limited NPP by giant kelp under otherwise favorable conditions. Regional patterns of interannual variation in NPP were similar to those of wave disturbance in that year-to-year variation in disturbance and NPP were both greater in southern California. Our findings provide strong evidence that regional differences in wave disturbance overwhelmed those of nutrient supply and grazing intensity to determine NPP by giant kelp. The important role of disturbance in controlling NPP revealed by our study is likely not unique to giant kelp forests, as vegetation dynamics in many systems are dominated by post-disturbance succession with climax communities being relatively uncommon. The effects of disturbance frequency may be easier to detect in giant kelp because it is fast growing and relatively short lived, with cycles of disturbance and recovery occurring on time scales of years. Much longer data sets (decades to centuries) will likely be needed to properly evaluate the role of disturbance relative to other processes in determining patterns of NPP in other systems.

Variations of Global Terrestrial Primary Production Observed by Moderate Resolution Imaging Spectroradiometer (MODIS) From 2000 to 2005

NASA Astrophysics Data System (ADS)

Zhao, M.; Running, S.; Heinsch, F. A.

2006-12-01

Since the first Earth Observing System (EOS) satellite Terra was launched in December 1999 and Moderate Resolution Imaging Spectroradiometer (MODIS) sensor onboard Terra began to provide data in February 2000, we have had six-year MODIS global 1-km terrestrial Gross and Net Primary Production (GPP &NPP) datasets. In this article, we present the variations (seasonality and inter-annual variability) of global GPP/NPP from the latest improved Collection 4.8 (C4.8) MODIS datasets for the past six-year (2000 - 2005), as well as improvements of the algorithm, validations of GPP and NPP. Validation results show that the C4.8 data have higher accuracy and quality than the previous version. Analyses of the variations in GPP/NPP show that GPP not only can reflect strong seasonality of photosynthesis activities by plants in mid- and high-latitude, but importantly, can reveal enhanced growth of Amazon rainforests during dry season, consistent with the reports by Huete et al. (2006) on GRL. Spatially, plants over mid- and high-latitude (north to 22.5°N) are the major contributor of global GPP seasonality. Inter-annual variability of MODIS NPP for 2000 - 2005 reveals the negative effects of major droughts on carbon sequestration at the regional and continental scales. A striking phenomenon is that the severe drought in 2005 over Amazon reduced NPP, indicating water availability becomes the dominant limiting factor rather than solar radiation under normal conditions. GMAO and NCEP driven global total NPPs have the similar interannual anomalies, and they generally follow the inverted CO2 growth rate anomaly with correlation of 0.85 and 0.91, respectively, which are higher than the correlation of 0.7 found by Nemani et al. (2003) on Science. Though there are only 6 years of MODIS data, results show that global NPP decreased from 2000 to 2005, and spatially most decreased NPP areas are in tropic and south hemisphere.

Net primary productivity distribution in the BOREAS region from a process model using satellite and surface data

NASA Astrophysics Data System (ADS)

Liu, J.; Chen, J. M.; Cihlar, J.; Chen, W.

1999-11-01

The purpose of this paper is to upscale tower measurements of net primary productivity (NPP) to the Boreal Ecosystem-Atmosphere Study (BOREAS) study region by means of remote sensing and modeling. The Boreal Ecosystem Productivity Simulator (BEPS) with a new daily canopy photosynthesis model was first tested in one coniferous and one deciduous site. The simultaneous CO2 flux measurements above and below the tree canopy made it possible to isolate daily net primary productivity of the tree canopy for model validation. Soil water holding capacity and gridded daily meteorological data for the region were used as inputs to BEPS, in addition to 1 km resolution land cover and leaf area index (LAI) maps derived from the advanced very high resolution radiometer (AVHRR) data. NPP statistics for the various cover types in the BOREAS region and in the southern study area (SSA) and the northern study area (NSA) are presented. Strong dependence of NPP on LAI was found for the three major cover types: coniferous forest, deciduous forest and cropland. Since BEPS can compute total photosynthetically active radiation absorbed by the canopy in each pixel, light use efficiencies for NPP and gross primary productivity could also be analyzed. From the model results, the following area-averaged statistics were obtained for 1994: (1) mean NPP for the BOREAS region of 217 g C m-2 yr-1; (2) mean NPP of forests (excluding burnt areas in the region) equal to 234 g C m-2 yr-1; (3) mean NPP for the SSA and the NSA of 297 and 238 g C m-2 yr-1, respectively; and (4) mean light use efficiency for NPP equal to 0.40, 0.20, and 0.33 g C (MJ APAR)-1 for deciduous forest, coniferous forest, and crops, respectively.

MODIS GPP/NPP for complex land use area: a case study of comparison between MODIS GPP/NPP and ground-based measurements over Korea

NASA Astrophysics Data System (ADS)

Shim, C.

2013-12-01

The Moderate Resolution Imaging Radiometer (MODIS) Gross Primary Productivity (GPP)/Net Primary Productivity (NPP) has been widely used for the study on global terrestrial ecosystem and carbon cycle. The current MODIS product with ~ 1 km spatial resolution, however, has limitation on the information on local scale environment (< 1km), particularly on the regions with complex land-use types. Here we try to test the performance of MODIS annual GPP/NPP for a case of Korea, where the vegetation types are mostly heterogeneous within a size of MODIS products (~1km). We selected the sites where the ground/tower flux measurements and MODIS retrievals were simultaneously available and the land classification of sites agreed the forest type map (~71m) (1 site over Gwangneung flux tower (GDK) for 2006-2008 and 2 sites of ground measurements over Cheongju (CJ1 and CJ2) for 2011). The MODIS GPP are comparable to that of GDK (largely deciduous forest) within -6.3 ~ +2.3% of bias (-104.5 - 37.9 gCm-2yr-1). While the MODIS NPP of CJ1 at Cheongju (largely Larix leptolepis) underestimated NPP by 34% (-224.5 gCm-2yr-1), the MODIS NPP of CJ2 (largely Pinus densiflora) agreed well with -0.2% of bias (1.6 gCm-2yr-1). The fairly comparable values of the MODIS here however, cannot assure the quality of the MOD17 over the complex vegetation area of Korea since the ground measurements except the eddy covariance tower flux measurements are highly inconsistent. Therefore, the comprehensive experiments to represents GPP/NPP over diverse vegetation types for a comparable scale of MODIS with a consistent measurement technique are necessary in order to evaluate the MODIS vegetation productivity data over Korea, which contains a large portion of highly heterogeneous vegetation area.

Vulnerability of tropical forest ecosystems and forest dependent communities to droughts.

PubMed

Vogt, D J; Vogt, K A; Gmur, S J; Scullion, J J; Suntana, A S; Daryanto, S; Sigurðardóttir, R

2016-01-01

Energy captured by and flowing through a forest ecosystem can be indexed by its total Net Primary Productivity (NPP). This forest NPP can also be a reflection of its sensitivity to, and its ability to adapt to, any climate change while also being harvested by humans. However detecting and identifying the vulnerability of forest and human ecosystems to climate change requires information on whether these coupled social and ecological systems are able to maintain functionality while responding to environmental variability. To better understand what parameters might be representative of environmental variability, we compiled a metadata analysis of 96 tropical forest sites. We found that three soil textural classes (i.e., sand, sandy loam and clay) had significant but different relationships between NPP and precipitation levels. Therefore, assessing the vulnerability of forests and forest dependent communities to drought was carried out using data from those sites that had one of those three soil textural classes. For example, forests growing on soil textures of sand and clay had NPP levels decreasing as precipitation levels increased, in contrast to those forest sites that had sandy loam soils where NPP levels increased. Also, forests growing on sandy loam soil textures appeared better adapted to grow at lower precipitation levels compared to the sand and clay textured soils. In fact in our tropical database the lowest precipitation level found for the sandy loam soils was 821 mm yr(-1) compared to sand at 1739 mm yr(-1) and clay at 1771 mm yr(-1). Soil texture also determined the level of NPP reached by a forest, i.e., forest growing on sandy loam and clay reached low-medium NPP levels while higher NPP levels (i.e., medium, high) were found on sand-textured soils. Intermediate precipitation levels (>1800-3000 mm yr(-1)) were needed to grow forests at the medium and high NPP levels. Low thresholds of NPP were identified at both low (∼750 mm) and high precipitation (>3500 mm) levels. By combining data on the ratios of precipitation to the amount of biomass produced in a year with how much less precipitation input occurs during a drought year, it is possible to estimate whether productivity levels are sufficient to support forest growth and forest dependent communities following a drought. In this study, the ratios of annual precipitation inputs required to produce 1 Mg ha(-1) yr(-1) biomass by soil texture class varied across the three soil textural classes. By using a conservative estimate of 20% of productivity collected or harvested by people and 30% precipitation reduction level as triggering a drought, it was possible to estimate a potential loss of annual productivity due to a drought. In this study, the total NPP unavailable due to drought and harvest by forest dependent communities per year was 10.2 Mg ha(-1) yr(-1) for the sandy textured soils (64% of NPP still available), 8.4 Mg ha(-1) yr(-1) for the sandy loam textured soils (60% available) and 12.7 Mg ha(-1) yr(-1) for the clay textured soils (29% available). Forests growing on clay textured soils would be most vulnerable to drought triggered reductions in productivity so NPP levels would be inadequate to maintain ecosystem functions and would potentially cause a forest-to-savanna shift. Further, these forests would not be able to provide sufficient NPP to satisfy the requirements of forest dependent communities. By predicting the productivity responses of different tropical forest ecosystems to changes in precipitation patterns coupled with edaphic data, it could be possible to spatially identify where tropical forests are most vulnerable to climate change impacts and where mitigation efforts should be concentrated. Copyright © 2015 Elsevier Inc. All rights reserved.

Drought stress and carbon uptake in an Amazon forest measured with spaceborne imaging spectroscopy

PubMed Central

Asner, Gregory P.; Nepstad, Daniel; Cardinot, Gina; Ray, David

2004-01-01

Amazônia contains vast stores of carbon in high-diversity ecosystems, yet this region undergoes major changes in precipitation affecting land use, carbon dynamics, and climate. The extent and structural complexity of Amazon forests impedes ground studies of ecosystem functions such as net primary production (NPP), water cycling, and carbon sequestration. Traditional modeling and remote-sensing approaches are not well suited to tropical forest studies, because (i) biophysical mechanisms determining drought effects on canopy water and carbon dynamics are poorly known, and (ii) remote-sensing metrics of canopy greenness may be insensitive to small changes in leaf area accompanying drought. New spaceborne imaging spectroscopy may detect drought stress in tropical forests, helping to monitor forest physiology and constrain carbon models. We combined a forest drought experiment in Amazônia with spaceborne imaging spectrometer measurements of this area. With field data on rainfall, soil water, and leaf and canopy responses, we tested whether spaceborne hyperspectral observations quantify differences in canopy water and NPP resulting from drought stress. We found that hyperspectral metrics of canopy water content and light-use efficiency are highly sensitive to drought. Using these observations, forest NPP was estimated with greater sensitivity to drought conditions than with traditional combinations of modeling, remote-sensing, and field measurements. Spaceborne imaging spectroscopy will increase the accuracy of ecological studies in humid tropical forests. PMID:15071182

Analysing Trends in Light-Use Efficiency and Their Influence on Seasonal CO2 Amplitude Using a Simple Land Ecosystem Model

NASA Astrophysics Data System (ADS)

Thomas, R.; Prentice, I. C. C.; Graven, H. D.

2016-12-01

A simple model for gross primary production (GPP), the P-model, is used to analyse the recent increase in the amplitude of the seasonal cycle of CO2 (ASC) at high northern latitudes. Current terrestrial biosphere models and Earth System Models generally underestimate the observed increase in ASC since 1960. The increased ASC is primarily driven by an increase in net primary productivity (NPP), rather than respiration, so models are likely underestimating increases in NPP. In a recent study of process-based terrestrial biosphere models from the Multi-scale Synthesis and Terrestrial Model Intercomparison Project (MsTMIP), we showed that the concept of light-use efficiency can be used to separate modelled NPP changes into structural and physiological components (Thomas et al, 2016). The structural component (leaf area) can be tested against observations of greening, while the physiological component (light-use efficiency) is an emergent model property. The analysis suggests that current models are capturing the increases in vegetation greenness, but underestimating the increases in light-use efficiency and NPP. We test this hypothesis using the P-model, which explicitly uses greenness data and includes the effects of rising CO2 and climate change. In the P-model, GPP is calculated using only a few equations, which are based on a strong empirical and theoretical framework, and vegetation is not separated into plant functional types. The model is driven by observed greenness, CO2, temperature and vapour pressure, and modelled photosynthetically active radiation at a monthly time-step. Photosynthetic assimilation is based on two key assumptions: the co-limitation hypothesis (electron transport- and Rubisco-limited photosynthetic rates are equal), and the least-cost hypothesis (optimal ci:ca ratio), and is limited by modelled soil moisture. We present simulated changes in GPP over the satellite period (1982-2011) in the P-model, and assess the associated changes in light-use efficiency and ASC. Our results have implications for the attribution of drivers of ecosystem change and the formulation of prognostic and diagnostic biosphere models. Thomas, R. T. et al. 2016, CO2 and greening observations indicate increasing light-use efficiency in Northern terrestrial ecosystems, Geophys Res Lett, in review.

Application of Nonlinear Seismic Soil-Structure Interaction Analysis for Identification of Seismic Margins at Nuclear Power Plants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Varma, Amit H.; Seo, Jungil; Coleman, Justin Leigh

2015-11-01

Seismic probabilistic risk assessment (SPRA) methods and approaches at nuclear power plants (NPP) were first developed in the 1970s and aspects of them have matured over time as they were applied and incrementally improved. SPRA provides information on risk and risk insights and allows for some accounting for uncertainty and variability. As a result, SPRA is now used as an important basis for risk-informed decision making for both new and operating NPPs in the US and in an increasing number of countries globally. SPRAs are intended to provide best estimates of the various combinations of structural and equipment failures thatmore » can lead to a seismic induced core damage event. However, in some instances the current SPRA approach contains large uncertainties, and potentially masks other important events (for instance, it was not the seismic motions that caused the Fukushima core melt events, but the tsunami ingress into the facility). INL has an advanced SPRA research and development (R&D) activity that will identify areas in the calculation process that contain significant uncertainties. One current area of focus is the use of nonlinear soil-structure interaction (NLSSI) analysis methods to accurately capture: 1) nonlinear soil behavior and 2) gapping and sliding between the NPP and soil. The goal of this study is to compare numerical NLSSI analysis results with recorded earthquake ground motions at Fukushima Daichii (Great Tohuku Earthquake) and evaluate the sources of nonlinearity contributing to the observed reduction in peak acceleration. Comparisons are made using recorded data in the free-field (soil column with no structural influence) and recorded data on the NPP basemat (in-structure response). Results presented in this study should identify areas of focus for future R&D activities with the goal of minimizing uncertainty in SPRA calculations. This is not a validation activity since there are too many sources of uncertainty that a numerical analysis would need to consider (variability in soil material properties, structural material properties, etc.). Rather the report will determine if the NLSSI calculations are following similar trends observed in the recorded data (i.e. reductions in maximum acceleration between the free-field and basemat) Numerical NLSSI results presented show maximum accelerations between the free field and basemat were reduced the EW and NS directions. The maximum acceleration in the UD direction increased slightly. The largest reduction in maximum accelerations between the modeled free-field and the NPP basemat resulted in nearly 50% reduction. The observation in reduction of numerical maximum accelerations in the EW and NS directions follows the observed trend in the recorded data. The maximum reductions observed in these NLSSI studies were due to soil nonlinearities, not gapping and sliding (although additional R&D is needed to develop an appropriate approach to model gapping and sliding). This exploratory study highlights the need for additional R&D on developing: (i) improved modeling of soil nonlinearities (soil constitutive models that appropriately capture cyclic soil behavior), (ii) improved modeling of gapping and sliding at the soil-structure interface (to appropriately capture the dissipation of energy at this interface), and (iii) experimental laboratory test data to calibrate the items (i) and (ii).« less

Environmental Problems Associated with Decommissioning of Chernobyl Power Plant Cooling Pond

NASA Astrophysics Data System (ADS)

Foley, T. Q.; Oskolkov, B. Y.; Bondarkov, M. D.; Gashchak, S. P.; Maksymenko, A. M.; Maksymenko, V. M.; Martynenko, V. I.; Jannik, G. T.; Farfan, E. B.; Marra, J. C.

2009-12-01

Decommissioning of nuclear power plants and other nuclear fuel cycle facilities associated with residual radioactive contamination is a fairly pressing issue. Significant problems may result from decommissioning of cooling ponds. The Chernobyl Nuclear Power Plant (ChNPP) Cooling Pond is one of the largest self-contained bodies of water in the Chernobyl Region and Ukrainian Polesye with a water surface area of 22.9 km2. The major hydrological feature of the ChNPP Cooling Pond is that its water level is 6-7 m higher than the water level in the Pripyat River and water losses due to seepage and evaporation are replenished by pumping water from the Pripyat River. In 1986, the accident at the ChNPP #4 Reactor Unit significantly contaminated the ChNPP Cooling Pond. According to the 2001 data, the total radionuclide inventory in the ChNPP Cooling Pond bottom deposits was as follows: 16.28 ± 2.59 TBq for 137Cs; 2.4 ± 0.48 TBq for 90Sr, and 0.00518 ± 0.00148 TBq for 239+240Pu. Since ChNPP is being decommissioned, the ChNPP Cooling Pond of such a large size will no longer be needed and cost effective to maintain. However, shutdown of the water feed to the Pond would expose the contaminated bottom deposits and change the hydrological features of the area, destabilizing the radiological and environmental situation in the entire region in 2007 - 2008, in order to assess potential consequences of draining the ChNPP Cooling Pond, the authors conducted preliminary radio-ecological studies of its shoreline ecosystems. The radioactive contamination of the ChNPP Cooling Pond shoreline is fairly variable and ranges from 75 to 7,500 kBq/m2. Three areas with different contamination levels were selected to sample soils, vegetation, small mammals, birds, amphibians, and reptilians in order to measure their 137Cs and 90Sr content. Using the ERICA software, their dose exposures were estimated. For the 2008 conditions, the estimated dose rates were found to be as follows: amphibians - 11.4 µGy/hr; birds - 6.3 µGy/hr; mammals - 15.1 µGy/hr; reptilians - 10.3 µGy/hr, with the recommended maximum allowable limit of 40 µGy/hr. The conservative risk coefficient ranged from 0.51 for birds to 1.82 for amphibians. In spite of a high contamination level of the shoreline areas, the current total doses received by the animals do not reach the recommended maximum allowable doses. However, drainage of the ChNPP Cooling Pond is likely to increase the dose rates as follows: amphibians - 94.5, birds - 95.2, mammals - 284.0, reptilians - 847.0 µGy/hr, which will significantly exceed the maximum allowable values. These predictions are conservative and prior to making the final decision on the fate of the ChNPP Cooling Pond, a detailed radio-ecological assessment of its drainage will have to be performed.

The Pseudomonas aeruginosa PA14 ABC Transporter NppA1A2BCD Is Required for Uptake of Peptidyl Nucleoside Antibiotics.

PubMed

Pletzer, Daniel; Braun, Yvonne; Dubiley, Svetlana; Lafon, Corinne; Köhler, Thilo; Page, Malcolm G P; Mourez, Michael; Severinov, Konstantin; Weingart, Helge

2015-07-01

Analysis of the genome sequence of Pseudomonas aeruginosa PA14 revealed the presence of an operon encoding an ABC-type transporter (NppA1A2BCD) showing homology to the Yej transporter of Escherichia coli. The Yej transporter is involved in the uptake of the peptide-nucleotide antibiotic microcin C, a translation inhibitor that targets the enzyme aspartyl-tRNA synthetase. Furthermore, it was recently shown that the Opp transporter from P. aeruginosa PAO1, which is identical to Npp, is required for uptake of the uridyl peptide antibiotic pacidamycin, which targets the enzyme translocase I (MraY), which is involved in peptidoglycan synthesis. We used several approaches to further explore the substrate specificity of the Npp transporter. Assays of growth in defined minimal medium containing peptides of various lengths and amino acid compositions as sole nitrogen sources, as well as Biolog Phenotype MicroArrays, showed that the Npp transporter is not required for di-, tri-, and oligopeptide uptake. Overexpression of the npp operon increased susceptibility not just to pacidamycin but also to nickel chloride and the peptidyl nucleoside antibiotic blasticidin S. Furthermore, heterologous expression of the npp operon in a yej-deficient mutant of E. coli resulted in increased susceptibility to albomycin, a naturally occurring sideromycin with a peptidyl nucleoside antibiotic. Additionally, heterologous expression showed that microcin C is recognized by the P. aeruginosa Npp system. Overall, these results suggest that the NppA1A2BCD transporter is involved in the uptake of peptidyl nucleoside antibiotics by P. aeruginosa PA14. One of the world's most serious health problems is the rise of antibiotic-resistant bacteria. There is a desperate need to find novel antibiotic therapeutics that either act on new biological targets or are able to bypass known resistance mechanisms. Bacterial ABC transporters play an important role in nutrient uptake from the environment. These uptake systems could also be exploited by a Trojan horse strategy to facilitate the transport of antibiotics into bacterial cells. Several natural antibiotics mimic substrates of peptide uptake routes. In this study, we analyzed an ABC transporter involved in the uptake of nucleoside peptidyl antibiotics. Our data might help to design drug conjugates that may hijack this uptake system to gain access to cells. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Effects of phosphorus level and phytase in broiler breeder rearing and laying diets on live performance and phosphorus excretion.

PubMed

Plumstead, P W; Romero-Sanchez, H; Maguire, R O; Gernat, A G; Brake, J

2007-02-01

The effects of a reduced dietary nonphytate phosphorus (NPP) level and inclusion of phytase on broiler breeder performance and P concentrations in the litter and manure were investigated. Ross 308 broiler breeder pullets and Ross 344 cockerels were placed sex-separate in a blackout growing house and fed standard starter and grower diets to 9 wk of age. At 10 wk of age, 4 treatments (A, B, C, D) were assigned to each of 4 floor pens of 68 pullets and 1 pen of 50 cockerels. From 10 to 21 wk, treatments A to D contained 0.37, 0.27, 0.27, and 0.17% NPP, respectively, with 300 phytase units (FTU)/kg of phytase added to treatments B and D. At 21 wk of age, birds were photostimulated and transferred to a two-thirds slat-litter breeder house with 16 pens of 60 pullets and 6 cockerels. A laying diet was fed from 22 to 64 wk and NPP levels of treatments A to D were adjusted to 0.37, 0.27, 0.19, and 0.09%, respectively, and phytase addition to treatments B and D was increased to 500 FTU/kg. Analysis of the litter from growing pens showed no effect on litter total P when phytase replaced 0.1% of NPP. However, decreasing the dietary NPP by 0.1% without phytase reduced the litter total P by 18%. Water-soluble P (WSP) and the WSP:total P ratio decreased when the grower dietary NPP level was reduced to 0.17% with added phytase and was correlated with litter moisture levels in growing pens. During the laying period, a reduction in NPP from 0.37 to 0.09% with added phytase reduced both the manure total P and WSP by 42%. Hen-day egg production was highest on the lowest NPP diet with phytase, but fertility decreased when the dietary NPP was reduced below 0.37%. Results showed that phytase inclusion in a broiler breeder laying diet at the expense of all added P from dicalcium phosphate reduced the manure total P and WSP concentrations by 42%, with no effect on the number of chicks produced per hen housed.

Testing for a CO2 fertilization effect on growth of Canadian boreal forests

NASA Astrophysics Data System (ADS)

Girardin, Martin P.; Bernier, Pierre Y.; Raulier, FréDéRic; Tardif, Jacques C.; Conciatori, France; Guo, Xiao Jing

2011-03-01

The CO2 fertilization hypothesis stipulates that rising atmospheric CO2 has a direct positive effect on net primary productivity (NPP), with experimental evidence suggesting a 23% growth enhancement with a doubling of CO2. Here, we test this hypothesis by comparing a bioclimatic model simulation of NPP over the twentieth century against tree growth increment (TGI) data of 192 Pinus banksiana trees from the Duck Mountain Provincial Forest in Manitoba, Canada. We postulate that, if a CO2 fertilization effect has occurred, climatically driven simulations of NPP and TGI will diverge with increasing CO2. We use a two-level scaling approach to simulate NPP. A leaf-level model is first used to simulate high-frequency responses to climate variability. A canopy-level model of NPP is then adjusted to the aggregated leaf-level results and used to simulate yearly plot-level NPP. Neither model accounts for CO2 fertilization. The climatically driven simulations of NPP for 1912-2000 are effective for tracking the measured year-to-year variations in TGI, with 47.2% of the variance in TGI reproduced by the simulation. In addition, the simulation reproduces without divergence the positive linear trend detected in TGI over the same period. Our results therefore do not support the attribution of a portion of the historical linear trend in TGI to CO2 fertilization at the level suggested by current experimental evidence. A sensitivity analysis done by adding an expected CO2 fertilization effect to simulations suggests that the detection limit of the study is for a 14% growth increment with a doubling of atmospheric CO2 concentration.

Spatio-temporal variations in climate, primary productivity and efficiency of water and carbon use of the land cover types in Sudan and Ethiopia.

PubMed

Khalifa, Muhammad; Elagib, Nadir Ahmed; Ribbe, Lars; Schneider, Karl

2018-05-15

The impact of climate variability on the Net Primary Productivity (NPP) of different land cover types and the reaction of NPP to drought conditions are still unclear, especially in Sub-Saharan Africa. This research utilizes public-domain data for the period 2000 through 2013 to analyze these aspects for several land cover types in Sudan and Ethiopia, as examples of data-scarce countries. Spatio-temporal variation in NPP, water use efficiency (WUE) and carbon use efficiency (CUE) for several land covers were correlated with variations in precipitation, temperature and drought at different time scales, i.e. 1, 3, 6 and 12months using Standardized Precipitation Evapotranspiration Index (SPEI) datasets. WUE and CUE were estimated as the ratios of NPP to actual evapotranspiration and NPP to Gross Primary Productivity (GPP), respectively. Results of this study revealed that NPP, WUE and CUE of the different land cover types in Ethiopia have higher magnitudes than their counterparts in Sudan. Moreover, they exhibit higher sensitivity to drought and variation in precipitation. Whereas savannah represents the most sensitive land cover to drought, croplands and permanent wetlands are the least sensitive ones. The inter-annual variation in NPP, WUE and CUE in Ethiopia is likely to be driven by a drought of time scale of three months. No statistically significant correlation was found for Sudan between the inter-annual variations in these indicators with drought at any of the time scales considered in the study. Our findings are useful from the view point of both food security for a growing population and mitigation to climate change as discussed in the present study. Copyright © 2017 Elsevier B.V. All rights reserved.

Lessons Learned from the Deployment and Integration of a Microwave Sounder Based Tropical Cyclone Intensity and Surface Wind Estimation Algorithm into NOAA/NESDIS Satellite Product Operations

NASA Astrophysics Data System (ADS)

Longmore, S. P.; Knaff, J. A.; Schumacher, A.; Dostalek, J.; DeMaria, R.; Chirokova, G.; Demaria, M.; Powell, D. C.; Sigmund, A.; Yu, W.

2014-12-01

The Colorado State University (CSU) Cooperative Institute for Research in the Atmosphere (CIRA) has recently deployed a tropical cyclone (TC) intensity and surface wind radii estimation algorithm that utilizes Suomi National Polar-orbiting Partnership (S-NPP) satellite Advanced Technology Microwave Sounder (ATMS) and Advanced Microwave Sounding Unit (AMSU) from the NOAA18, NOAA19 and METOPA polar orbiting satellites for testing, integration and operations for the Product System Development and Implementation (PSDI) projects at NOAA's National Environmental Satellite, Data, and Information Service (NESDIS). This presentation discusses the evolution of the CIRA NPP/AMSU TC algorithms internally at CIRA and its migration and integration into the NOAA Data Exploitation (NDE) development and testing frameworks. The discussion will focus on 1) the development cycle of internal NPP/AMSU TC algorithms components by scientists and software engineers, 2) the exchange of these components into the NPP/AMSU TC software systems using the subversion version control system and other exchange methods, 3) testing, debugging and integration of the NPP/AMSU TC systems both at CIRA/NESDIS and 4) the update cycle of new releases through continuous integration. Lastly, a discussion of the methods that were effective and those that need revision will be detailed for the next iteration of the NPP/AMSU TC system.

Effects of fire and CO2 on biogeography and primary production in glacial and modern climates.

PubMed

Martin Calvo, Maria; Prentice, Iain Colin

2015-11-01

Dynamic global vegetation models (DGVMs) can disentangle causes and effects in the control of vegetation and fire. We used a DGVM to analyse climate, CO2 and fire influences on biome distribution and net primary production (NPP) in last glacial maximum (LGM) and pre-industrial (PI) times. The Land surface Processes and eXchanges (LPX) DGVM was run in a factorial design with fire 'off' or 'on', CO2 at LGM (185 ppm) or PI (280 ppm) concentrations, and LGM (modelled) or recent climates. Results were analysed by Stein-Alpert decomposition to separate primary effects from synergies. Fire removal causes forests to expand and global NPP to increase slightly. Low CO2 greatly reduces forest area (dramatically in a PI climate; realistically under an LGM climate) and global NPP. NPP under an LGM climate was reduced by a quarter as a result of low CO2 . The reduction in global NPP was smaller at low temperatures, but greater in the presence of fire. Global NPP is controlled by climate and CO2 directly through photosynthesis, but also through biome distribution, which is strongly influenced by fire. Future vegetation simulations will need to consider the coupled responses of vegetation and fire to CO2 and climate. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

Net Primary Production of Terrestrial Ecosystems from 2000 to 2009

NASA Technical Reports Server (NTRS)

Potter, Christopher; Klooster, Steven; Genovese, Vanessa

2012-01-01

The CASA (Carnegie-Ames-Stanford) ecosystem model has been used to estimate monthly carbon fluxes in terrestrial ecosystems from 2000 to 2009, with global data inputs from NASA's Terra Moderate Resolution Imaging Spectroradiometer (MODIS) vegetation cover mapping. Net primary production (NPP) flux for atmospheric carbon dioxide has varied slightly from year-to-year, but was predicted to have increased over short multi-year periods in the regions of the high-latitude Northern Hemisphere, South Asia, Central Africa, and the western Amazon since the year 2000. These CASA results for global NPP were found to be in contrast to other recently published modeling trends for terrestrial NPP with high sensitivity to regional drying patterns. Nonetheless, periodic declines in regional NPP were predicted by CASA for the southern and western Untied States, the southern Amazon, and southern and eastern Africa. NPP in tropical forest zones was examined in greater detail to discover lower annual production values than previously reported in many global models across the tropical rainforest zones, likely due to the enhanced detection of lower production ecosystems replacing primary rainforest.

Multiyear predictability of tropical marine productivity

PubMed Central

Séférian, Roland; Bopp, Laurent; Gehlen, Marion; Swingedouw, Didier; Mignot, Juliette; Guilyardi, Eric; Servonnat, Jérôme

2014-01-01

With the emergence of decadal predictability simulations, research toward forecasting variations of the climate system now covers a large range of timescales. However, assessment of the capacity to predict natural variations of relevant biogeochemical variables like carbon fluxes, pH, or marine primary productivity remains unexplored. Among these, the net primary productivity (NPP) is of particular relevance in a forecasting perspective. Indeed, in regions like the tropical Pacific (30°N–30°S), NPP exhibits natural fluctuations at interannual to decadal timescales that have large impacts on marine ecosystems and fisheries. Here, we investigate predictions of NPP variations over the last decades (i.e., from 1997 to 2011) with an Earth system model within the tropical Pacific. Results suggest a predictive skill for NPP of 3 y, which is higher than that of sea surface temperature (1 y). We attribute the higher predictability of NPP to the poleward advection of nutrient anomalies (nitrate and iron), which sustain fluctuations in phytoplankton productivity over several years. These results open previously unidentified perspectives to the development of science-based management approaches to marine resources relying on integrated physical-biogeochemical forecasting systems. PMID:25071174

Simulation of Hydrogen Distribution in Ignalina NPP ALS Compartments During BDBA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Babilas, Egidijus; Urbonavicius, Egidijus; Rimkevicius, Sigitas

2006-07-01

Accident Localisation System (ALS) of Ignalina NPP is a 'pressure suppression' type confinement, which protects the population, employees and environment from the radiation hazards. According to the Safety Analysis Report for Ignalina NPP {approx}110 m{sup 3} of hydrogen is released to ALS compartments during the Maximum Design Basis Accident. However in case of beyond design basis accident, when the oxidation of zirconium starts, the amount of generated hydrogen could be significantly higher. If the volume concentration of hydrogen in the compartment reaches 4%, there is a possibility for a combustible mixture to appear. To prevent the possible hydrogen accumulation inmore » the ALS of the Ignalina NPP during an accident the H{sub 2} control system is installed. The results of the performed analysis derived the places of the possible H{sub 2} accumulation in the ALS compartments during the transient processes and assessed the mixture combustibility in these places for a beyond design basis accident scenario. Such analysis of H{sub 2} distribution in the ALS of Ignalina NPP in case of BDBA was not performed before. (authors)« less

Modified Light Use Efficiency Model for Assessment of Carbon Sequestration in Grasslands of Kazakhstan: Combining Ground Biomass Data and Remote-sensing

NASA Technical Reports Server (NTRS)

Propastin, Pavel A.; Kappas, Martin W.; Herrmann, Stefanie M.; Tucker, Compton J.

2012-01-01

A modified light use efficiency (LUE) model was tested in the grasslands of central Kazakhstan in terms of its ability to characterize spatial patterns and interannual dynamics of net primary production (NPP) at a regional scale. In this model, the LUE of the grassland biome (en) was simulated from ground-based NPP measurements, absorbed photosynthetically active radiation (APAR) and meteorological observations using a new empirical approach. Using coarse-resolution satellite data from the Sea-viewing Wide Field-of-view Sensor (SeaWiFS), monthly NPP was calculated from 1998 to 2008 over a large grassland region in Kazakhstan. The modelling results were verified against scaled up plot-level observations of grassland biomass and another available NPP data set derived from a field study in a similar grassland biome. The results indicated the reliability of productivity estimates produced by the model for regional monitoring of grassland NPP. The method for simulation of en suggested in this study can be used in grassland regions where no carbon flux measurements are accessible.

[The distribution of radiation-induced breaks in the chromosomes of irradiated subjects].

PubMed

Shemetun, O V; Pidlins'ka, M A; Shemetun, H M

2000-01-01

Distribution of radiation-induced breakpoints in chromosomes and its bands in persons recovered from acute radiation sickness and personnel from Chernobyl NPP were investigated using G-banding staining. The frequency of damaged bands and breakpoints in groups exposed to radiation was significantly higher as compared with the control group. It was shown that in exposed to radiation persons damage depends on its length. Most frequently damaged bands in the observed groups were determined. The G-negative bands and telomeres of chromosomes were more sensitive to radiation.

Transfusion of Plasma Collected at Late Phase after Preconditioning Reduces Myocardial Infarct Size Induced by Ischemia-reperfusion in Rats In vivo.

PubMed

Zhao, Yang; Zheng, Zhi-Nan; Cheung, Chi-Wai; Zuo, Zhi-Yi; Jin, San-Qing

2017-02-05

Plasma transfusion is a common clinical practice. Remote ischemic preconditioning (RIPC) protects organs against ischemia-reperfusion (IR) injury. Whether preconditioned plasma (PP), collected at late phase after RIPC, could protect organs against IR injury in vivo is unknown. This study explored whether transfusion of PP could reduce myocardial infarct size (IS) after IR in rat in vivo. Eighty Lewis rats were randomized to eight groups (n = 10 for each group). Two groups of plasma donor rats donated plasma at 48 h after transient limb ischemia (PP) or control protocol (nonpreconditioned plasma [NPP]). Six groups of recipient rats received normal saline (NS; NS-IR 1, and NS-IR 24 groups), NPP (NPP-IR 1 and NPP-IR 24 groups), or PP (PP-IR 1 and PP-IR 24 groups) at one or 24 h before myocardial IR. Myocardial IR consisted of 30-min left anterior descending (LAD) coronary artery occlusion and 180-min reperfusion. The area at risk (AAR) and infarct area were determined by double-staining with Evans blue and triphenyltetrazolium chloride. IS was calculated by infarct area divided by AAR. This was a 3 × 2 factorial design study, and factorial analysis was used to evaluate the data. If an interaction between the fluid and transfusion time existed, one-way analysis of variance with Bonferroni correction for multiple comparisons was used to analyze the single effects of fluid type when the transfusion time was fixed. IS in the NPP-IR 1 and PP-IR 1 groups was smaller than in the NS-IR 1 group (F = 6.838, P = 0.005; NPP-IR 1: 57 ± 8% vs. NS-IR1: 68 ± 6%, t = 2.843, P = 0.020; PP-IR 1: 56 ± 8% vs. NS-IR 1: 68 ± 6%, t = 3.102, P = 0.009), but no significant difference was detected between the NPP-IR 1 and PP-IR 1 groups (57 ± 8% vs. 56 ± 8%, t = 0.069, P = 1.000). IS in the NPP-IR 24 and PP-IR 24 groups was smaller than in the NS-IR 24 group (F = 24.796, P< 0.001; NPP-IR 24: 56% ± 7% vs. NS-IR 24: 68 ± 7%, t = 3.102, P = 0.026; PP-IR 24: 40 ± 9% vs. NS-IR 24: 68 ± 7%, t = 7.237, P< 0.001); IS in the PP-IR 24 group was smaller than in the NPP-IR 24 group (40 ± 9% vs. 56 ± 7%, t = 4.135, P = 0.002). Transfusion of PP collected at late phase after remote ischemic preconditioning could reduce IS, suggesting that late-phase cardioprotection was transferable in vivo.

Effects of active forest fire on terrestrial ecosystem production and greenhouse gas emissions

NASA Astrophysics Data System (ADS)

Sannigrahi, Srikanta; Rahmat, Shahid; Bhatt, Sandeep; Rana, Virendra

2017-04-01

The forest fire is one of the most catalysing agents which degrade an ecosystems leading to the loss of net and gross primary productivity (NPP & GPP) and carbon sequestration service. Additionally, it can suppress the efficiency of service providing capacity of an ecosystem throughout the time and space. Remote sensing-based forest fire estimation in a diverse ecosystem is very much essential for mitigating the biodiversity and productivity losses due to the forest fire. Satellite-based Land Surface Temperature (LST) has been calculated for the pre-fire and fire years to identify the burn severity hotspot across all eco-regions in the Lower Himalaya region. Several burn severity indices: Normalized Burn Ratio (NBR), Burnt Area Index (BAI), Normalized Multiband Drought Index (NMDI), Soil Adjusted Vegetation Index (SAVI), Global Environmental Monitoring Index (GEMI), Enhance Vegetation Index (EVI) have been used in this study to quantify the spatial and temporal changes (delta) of the selected indices. Two Light Use Efficiency (LUE) models: Carnegie- Ames-Stanford-Approach (CASA) and Vegetation Photosynthesis Model (VPM) have been used to quantify the terrestrial Net Primary Productivity (NPP) in the pre-fire and fire years across all biomes of the region. A novel approach has been preceded in this field to demonstrate the correlation between forest fire density (FFD) and NPP. A strong positive correlation was found between burn severity indices and predicted NPP: BAI and NPP (r = 0.49), NBR and NPP: (r = 0.58), EVI and NPP: (r = 0.72), SAVI and NPP: (r = 0.67), whereas, a negative association has noted between the NMDI and NPP: (r = -0.36) during the both studied years. Results have shown that the NPP is highly correlated with the forest fire density (R2 = 0.75, RMSE = 5.03 gC m-2 month-1). The estimated LST of the individual fire days has witnessed a sharp temperature increase by > 6oC - 9oC in comparison to the non-fire days clearly indicates high fire risk (in Uttarakhand) due to the subtle water stress condition with lesser soil moisture content into the ground. Among the 13 districts, the maximum net emissions of carbon and nitrogen compounds have been observed in 7 districts (accounting for high biomass and forest cover loss by the 2016 forest fire), whereas, the rest of the 6 districts acts as the sequester of greenhouse compounds. This new approach having the potentiality of quantifying the losses of ecosystem productivity due to forest fires and could be used in broader aspects if more accurate field based observation can be obtained in the near future.

A GeoServices Infrastructure for Near-Real-Time Access to Suomi NPP Satellite Data

NASA Astrophysics Data System (ADS)

Evans, J. D.; Valente, E. G.; Hao, W.; Chettri, S.

2012-12-01

The new Suomi National Polar-orbiting Partnership (NPP) satellite extends NASA's moderate-resolution, multispectral observations with a suite of powerful imagers and sounders to support a broad array of research and applications. However, NPP data products consist of a complex set of data and metadata files in highly specialized formats; which NPP's operational ground segment delivers to users only with several hours' delay. This severely limits their use in critical applications such as weather forecasting, emergency / disaster response, search and rescue, and other activities that require near-real-time access to satellite observations. Alternative approaches, based on distributed Direct Broadcast facilities, can reduce the delay in NPP data delivery from hours to minutes, and can make products more directly usable by practitioners in the field. To assess and fulfill this potential, we are developing a suite of software that couples Direct Broadcast data feeds with a streamlined, scalable processing chain and geospatial Web services, so as to permit many more time-sensitive applications to use NPP data. The resulting geoservices infrastructure links a variety of end-user tools and applications to NPP data from different sources, and to other rapidly-changing geospatial data. By using well-known, standard software interfaces (such as OGC Web Services or OPeNDAP), this infrastructure serves a variety of end-user analysis and visualization tools, giving them access into datasets of arbitrary size and resolution and allowing them to request and receive tailored products on demand. The standards-based approach may also streamline data sharing among independent satellite receiving facilities, thus helping them to interoperate in providing frequent, composite views of continent-scale or global regions. To enable others to build similar or derived systems, the service components we are developing (based in part on the Community Satellite Processing Package (CSPP) from the University of Wisconsin and the International Polar-Orbiter Processing Package (IPOPP) from NASA) are being released as open source software. Furthermore, they are configured to operate in a cloud computing environment, so as to allow even small organizations to process and serve NPP data without large hardware investments; and to maintain near-real-time performance cost-effectively by growing and shrinking their use of computing resources to meet large, rapid fluctuations in end-user demand, data availability, and processing needs. (This is especially important for polar-orbiting satellites like NPP, which pass within range of a receiver only a few times each day.) We will discuss the design of the infrastructure, highlight its capabilities, and sketch its potential to facilitate broad access to satellite data processing and visualization, and to enhance near-real-time applications via distributed NPP data streams.

NPP After Launch: Characterizing ATMS Performance

NASA Technical Reports Server (NTRS)

Lambrigtsen, Bjorn

2011-01-01

The NPOESS Preparatory Project (NPP) mission is scheduled to launch in the fall of 2011. Although several teams from the government and the instrument contractor will be assessing and characterizing the performance of the Advanced Technology Microwave Sounder (ATMS) and the Cross-track Infrared Sounder (CrIS) sounding suite, the NASA NPP Science Team will be paying particular attention to the aspects of these sensors that affect their utility for atmospheric and climate research. In this talk we discuss relevant aspects of ATMS and our post launch analysis approach.

Terrestrial ecosystem model performance for net primary productivity and its vulnerability to climate change in permafrost regions

NASA Astrophysics Data System (ADS)

Xia, J.; McGuire, A. D.; Lawrence, D. M.; Burke, E.; Chen, X.; Delire, C. L.; Koven, C. D.; MacDougall, A. H.; Peng, S.; Rinke, A.; Saito, K.; Zhang, W.; Alkama, R.; Bohn, T. J.; Ciais, P.; Decharme, B.; Gouttevin, I.; Hajima, T.; Ji, D.; Krinner, G.; Lettenmaier, D. P.; Miller, P. A.; Moore, J. C.; Smith, B.; Sueyoshi, T.; Shi, Z.; Yan, L.; Liang, J.; Jiang, L.; Luo, Y.

2014-12-01

A more accurate prediction of future climate-carbon (C) cycle feedbacks requires better understanding and improved representation of the carbon cycle in permafrost regions within current earth system models. Here, we evaluated 10 terrestrial ecosystem models for their estimated net primary productivity (NPP) and its vulnerability to climate change in permafrost regions in the Northern Hemisphere. Those models were run retrospectively between 1960 and 2009. In comparison with MODIS satellite estimates, most models produce higher NPP (310 ± 12 g C m-2 yr-1) than MODIS (240 ± 20 g C m-2 yr-1) over the permafrost regions during 2000‒2009. The modeled NPP was then decomposed into gross primary productivity (GPP) and the NPP/GPP ratio (i.e., C use efficiency; CUE). By comparing the simulated GPP with a flux-tower-based database [Jung et al. Journal of Geophysical Research 116 (2011) G00J07] (JU11), we found although models only produce 10.6% higher mean GPP than JU11 over 1982‒2009, there was a two-fold disparity among models (397 to 830 g C m-2 yr-1). The model-to-model variation in GPP mainly resulted from the seasonal peak GPP and in low-latitudinal permafrost regions such as the Tibetan Plateau. Most models overestimate the CUE in permafrost regions in comparison to calculated CUE from the MODIS NPP and JU11 GPP products and observation-based estimates at 8 forest sites. The models vary in their sensitivities of NPP, GPP and CUE to historical changes in air temperature, atmospheric CO2 concentration and precipitation. For example, climate warming enhanced NPP in four models via increasing GPP but reduced NPP in two other models by decreasing both GPP and CUE. The results indicate that the model predictability of C cycle in permafrost regions can be improved by better representation of those processes controlling the seasonal maximum GPP and the CUE as well as their sensitivity to climate change.

Carbon lost and carbon gained: a study of vegetation and carbon trade-offs among diverse land uses in Phoenix, Arizona.

PubMed

McHale, Melissa R; Hall, Sharon J; Majumdar, Anandamayee; Grimm, Nancy B

2017-03-01

Human modification and management of urban landscapes drastically alters vegetation and soils, thereby altering carbon (C) storage and rates of net primary productivity (NPP). Complex social and ecological processes drive vegetation cover in cities, leading to heterogeneity in C dynamics depending on regional climate, land use, and land cover. Recent work has demonstrated homogenization in ecological processes within human-dominated landscapes (the urban convergence hypothesis) in soils and biotic communities. However, a lack of information on vegetation in arid land cities has hindered an understanding of potential C storage and NPP convergence across a diversity of ecosystem types. We estimated C storage and NPP of trees and shrubs for six different land-use types in the arid metropolis of Phoenix, Arizona, USA, and compared those results to native desert ecosystems, as well as other urban and natural systems around the world. Results from Phoenix do not support the convergence hypothesis. In particular, C storage in urban trees and shrubs was 42% of that found in desert vegetation, while NPP was only 20% of the total NPP estimated for comparable natural ecosystems. Furthermore, the overall estimates of C storage and NPP associated with urban trees in the CAP ecosystem were much lower (8-63%) than the other cities included in this analysis. We also found that C storage (175.25-388.94 g/m 2 ) and NPP (8.07-15.99 g·m -2 ·yr -1 ) were dominated by trees in the urban residential land uses, while in the desert, shrubs were the primary source for pools (183.65 g/m 2 ) and fluxes (6.51 g·m -2 ·yr -1 ). These results indicate a trade-off between shrubs and trees in arid ecosystems, with shrubs playing a major role in overall C storage and NPP in deserts and trees serving as the dominant C pool in cities. Our research supports current literature that calls for the development of spatially explicit and standardized methods for analyzing C dynamics associated with vegetation in urbanizing areas. © 2016 by the Ecological Society of America.

Response of broiler chickens to different levels of calcium, non-phytate phosphorus and phytase.

PubMed

Akter, M; Graham, H; Iji, P A

2016-12-01

1. Five hundred and seventy six-d old Ross 308 broiler chicks (6 cages per diet, 8 birds per cage in 3 × 2 × 2 factorial arrangement) were fed on maize-soybean meal-based diets containing three concentrations of Ca (6, 8 or 10 g/kg), two concentrations of non-phytate phosphorus (NPP) (3 or 4 g/kg) and two levels of exogenous microbial phytase (0 or 500 FTU/kg) from d 0 to 35. 2. Body weight (BW), feed intake (FI) and mortality records were collected. Two birds per replicate were killed at 24 d of age to obtain tibia samples. 3. Increasing Ca level significantly reduced the FI and body weight gain (BWG) between hatch and 10 and 24 d, especially with the phytase-supplemented diets. However, phytase supplementation of the diet containing 4 g NPP/kg improved the FI and BWG at d 10 and 24. At d 24, phytase supplementation improved feed conversion ratio (FCR) of birds that consumed diets containing high NPP. The overall FCR was better in birds offered the phytase-supplemented, medium-Ca diet. 4. There was a significant reduction in length, width and breaking strength of the tibia bone in birds fed on a diet with high Ca and low NPP. Phytase supplementation improved the tibia ash content and bone breaking strength of chicks fed on the diet containing 8 and 4 g/kg Ca and NPP, respectively. The Ca content of the tibia bone was low in birds fed on diets with 6 and 4 g/kg Ca and NPP, respectively, but this was counteracted by phytase supplementation. 5. Birds fed on diets with 4 g/kg NPP had the best carcass percentage and parts yield. Phytase supplementation to high-Ca diets significantly reduced the carcass yield of birds. 6. These results confirmed the detrimental effect of high dietary Ca on phytase activity and subsequent growth and bone development of birds, especially when NPP is in short supply.

Emerging Environmental Justice Issues in Nuclear Power and Radioactive Contamination.

PubMed

Kyne, Dean; Bolin, Bob

2016-07-12

Nuclear hazards, linked to both U.S. weapons programs and civilian nuclear power, pose substantial environment justice issues. Nuclear power plant (NPP) reactors produce low-level ionizing radiation, high level nuclear waste, and are subject to catastrophic contamination events. Justice concerns include plant locations and the large potentially exposed populations, as well as issues in siting, nuclear safety, and barriers to public participation. Other justice issues relate to extensive contamination in the U.S. nuclear weapons complex, and the mining and processing industries that have supported it. To approach the topic, first we discuss distributional justice issues of NPP sites in the U.S. and related procedural injustices in siting, operation, and emergency preparedness. Then we discuss justice concerns involving the U.S. nuclear weapons complex and the ways that uranium mining, processing, and weapons development have affected those living downwind, including a substantial American Indian population. Next we examine the problem of high-level nuclear waste and the risk implications of the lack of secure long-term storage. The handling and deposition of toxic nuclear wastes pose new transgenerational justice issues of unprecedented duration, in comparison to any other industry. Finally, we discuss the persistent risks of nuclear technologies and renewable energy alternatives.

Observation and simulation of net primary productivity in Qilian Mountain, western China.

PubMed

Zhou, Y; Zhu, Q; Chen, J M; Wang, Y Q; Liu, J; Sun, R; Tang, S

2007-11-01

We modeled net primary productivity (NPP) at high spatial resolution using an advanced spaceborne thermal emission and reflection radiometer (ASTER) image of a Qilian Mountain study area using the boreal ecosystem productivity simulator (BEPS). Two key driving variables of the model, leaf area index (LAI) and land cover type, were derived from ASTER and moderate resolution imaging spectroradiometer (MODIS) data. Other spatially explicit inputs included daily meteorological data (radiation, precipitation, temperature, humidity), available soil water holding capacity (AWC), and forest biomass. NPP was estimated for coniferous forests and other land cover types in the study area. The result showed that NPP of coniferous forests in the study area was about 4.4 tCha(-1)y(-1). The correlation coefficient between the modeled NPP and ground measurements was 0.84, with a mean relative error of about 13.9%.

Large divergence of satellite and Earth system model estimates of global terrestrial CO2 fertilization

USGS Publications Warehouse

Smith, W. Kolby; Reed, Sasha C.; Cleveland, Cory C.; Ballantyne, Ashley P; Anderegg, William R. L.; Wieder, William R.; Liu, Yi Y; Running, Steven W.

2015-01-01

Atmospheric mass balance analyses suggest that terrestrial carbon (C) storage is increasing, partially abating the atmospheric [CO2] growth rate, although the continued strength of this important ecosystem service remains uncertain. Some evidence suggests that these increases will persist owing to positive responses of vegetation growth (net primary productivity; NPP) to rising atmospheric [CO2] (that is, ‘CO2 fertilization’). Here, we present a new satellite-derived global terrestrial NPP data set, which shows a significant increase in NPP from 1982 to 2011. However, comparison against Earth system model (ESM) NPP estimates reveals a significant divergence, with satellite-derived increases (2.8 ± 1.50%) less than half of ESM-derived increases (7.6  ±  1.67%) over the 30-year period. By isolating the CO2 fertilization effect in each NPP time series and comparing it against a synthesis of available free-air CO2 enrichment data, we provide evidence that much of the discrepancy may be due to an over-sensitivity of ESMs to atmospheric [CO2], potentially reflecting an under-representation of climatic feedbacks and/or a lack of representation of nutrient constraints. Our understanding of CO2 fertilization effects on NPP needs rapid improvement to enable more accurate projections of future C cycle–climate feedbacks; we contend that better integration of modelling, satellite and experimental approaches offers a promising way forward.

NPP Runs the Gauntlet of Environmental Testing

NASA Image and Video Library

2017-12-08

NPP is lowered into the thermal vacuum chamber. Once inside the Iron Maiden (visible in the lower left) is fitted in place. Then air is pumped out of the chamber and temperature extremes are applied to replicate orbit conditions. Credit: Ball Aerospace The NPP satellite sits surrounded by 144 rock concert speakers. They're stacked in a circle 16 feet high in a testing room at Ball Aerospace in Boulder, Colorado. As engineers set up for the environmental test, Pink Floyd's song "Money" plays gently in the background. The music stops. The room clears. Then the sound engineer wearing earplugs and headphones in the control room next door flips a switch. Slowly, the noise of thousands of pounds of exploding rocket fuel builds louder and louder until it blasts the satellite at a deafening 143.6 decibels -- loud enough to cause serious damage and pain to unprotected ears. "I was outside the building when they did the full level acoustics," says Glenn Iona, NPP Chief Engineer at NASA Goddard Space Flight Center, Greenbelt, Md. "and I could feel the ground shaking." To read more go to: www.nasa.gov/mission_pages/NPP/news/npp-testing.html NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

Assessing the impact of urbanization on regional net primary productivity in Jiangyin County, China.

PubMed

Xu, C; Liu, M; An, S; Chen, J M; Yan, P

2007-11-01

Urbanization is one of the most important aspects of global change. The process of urbanization has a significant impact on the terrestrial ecosystem carbon cycle. The Yangtze Delta region has one of the highest rates of urbanization in China. In this study, carried out in Jiangyin County as a representative region within the Yangtze Delta, land use and land cover changes were estimated using Landsat TM and ETM+ imagery. With these satellite data and the BEPS process model (Boreal Ecosystem Productivity Simulator), the impacts of urbanization on regional net primary productivity (NPP) and annual net primary production were assessed for 1991 and 2002. Landsat-based land cover maps in 1991 and 2002 showed that urban development encroached large areas of cropland and forest. Expansion of residential areas and reduction of vegetated areas were the major forms of land transformation in Jiangyin County during this period. Mean NPP of the total area decreased from 818 to 699 gCm(-2)yr(-1) during the period of 1991 to 2002. NPP of cropland was only reduced by 2.7% while forest NPP was reduced by 9.3%. Regional annual primary production decreased from 808 GgC in 1991 to 691 GgC in 2002, a reduction of 14.5%. Land cover changes reduced regional NPP directly, and the increasing intensity and frequency of human-induced disturbance in the urbanized areas could be the main reason for the decrease in forest NPP.

Systemic analysis of desertification processes taking place in the Limpopo river basin

NASA Astrophysics Data System (ADS)

Messina, Mario; Attorre, Fabio; Vitale, Marcello

2016-04-01

Desertification and land degradation are phenomena that ranks among the greatest environmental challenges of our time. Desertification is a global issue, with serious implications worldwide for biodiversity, socio-economic stability and sustainable development. Biophysical indicators of land degradation and desertification, like Net Primary Productivity (NPP) and Total Ecosystem Respiration (Reco) were provided by remote sensing technology (MODIS). The study aims to evaluate the dynamical changes of NPP and Reco in the Limpopo river basin, a Southern African region that includes, Botswana, Mozambique, South Africa and Zimbabwe, during the time period 2001-2010. In particular, the relations between NPP, Reco, environmental, physiological and land use parameters have been widely investigated through the application of a new and powerful statistical classifier, the Random Forest Analysis (RFA), and a general non-linear model, the Response Surface Regression Model (GRM). RFA highlighted that Temperature is one of the most important predictors affecting NPP and Reco in the Limpopo river basin. Conversely, other environmental parameters like, Precipitation, Evapotranspiration and Vegetation cover rarely influence NPP and Reco. Our results provide information on desertification and land degradation phenomena and a first step for identifying practices to mitigate their negative impacts. However, it must be taken into account that NPP and Reco depend by a multitude of factors (e.g. human activities, socio-economic policies) and can vary in relation to spatial and temporal scale. In order to achieve a better understanding of land degradation and desertification processes, land use and socio-economic variables should be considered.

Surveillance of Strontium-90 in Foods after the Fukushima Daiichi Nuclear Power Plant Accident.

PubMed

Nabeshi, Hiromi; Tsutsumi, Tomoaki; Uekusa, Yoshinori; Hachisuka, Akiko; Matsuda, Rieko; Teshima, Reiko

2015-01-01

As a result of the Fukushima Daiichi nuclear power plant (NPP) accident, various radionuclides were released into the environment. In this study, we surveyed strontium-90 ((90)Sr) concentrations in several foodstuffs. Strontium-90 is thought to be the third most important residual radionuclide in food collected after the Fukushima Daiichi, NPP accident after following cesium-137 ((137)Cs) and cesium-134 ((134)Cs). Results of (90)Sr analyses indicated that (90)Sr was detect in 25 of the 40 radioactive cesium (r-Cs) positive samples collected in areas around the Fukushima Daiichi NPP, ranging in distance from 50 to 250 km. R-Cs positive samples were defined as containing both (134)Cs and (137)Cs which are considered to be indicators of the after-effects of the Fukushima Daiichi NPP accident. We also detected (90)Sr in 8 of 13 r-Cs negative samples, in which (134)Cs was not detected. Strontium-90 concentrations in the r-Cs positive samples did not significantly exceed the (90)Sr concentrations in r-Cs negative samples or the (90)Sr concentration ranges in comparable food groups found in previous surveys before the Fukushima Daiichi NPP accident. Thus, (90)Sr concentrations in r-Cs positive samples were indistinguishable from the background (90)Sr concentrations arising from global fallout prior to the Fukushima accident, suggesting that no marked increase of (90)Sr concentrations has occurred in r-Cs positive samples as a result of the Fukushima Daiichi NPP accident.

An optimal dietary non-phytate phosphorus level of broilers fed a conventional corn-soybean meal diet from 4 to 6 weeks of age.

PubMed

Jiang, Y; Lu, L; Li, S F; Wang, L; Zhang, L Y; Liu, S B; Luo, X G

2016-10-01

It is imperative to evaluate precise nutrient requirements of animals in order to optimize productivity and minimize feed cost and nutrient excretions. The current non-phytate phosphorus (NPP) recommendation for broilers is based on the papers published 30 years ago. However, today's commercial birds are quite different from those before 30 years. Therefore, the present experiment was conducted with growing male broiler chickens to evaluate an optimal dietary NPP level of broiler chickens fed a conventional corn-soybean meal diet from 4 to 6 weeks of age. The 1-day-old chicks were fed corn-soybean meal diet containing 0.39% NPP from 1 to 3 weeks of age. At 22 days of age, 360 birds were selected and randomly allotted by BW to one of 10 dietary treatments with six replicate cages of six birds per cage for each treatment. Birds were fed the P-unsupplemented corn-soybean meal basal diet and the basal diet supplemented with inorganic P as CaHPO4·H2O ranging from 0.00% to 0.45% with 0.05% increment from 4 to 6 weeks of age. The dietary NPP levels were 0.09%, 0.14%, 0.20%, 0.24%, 0.30%, 0.34%, 0.38%, 0.45%, 0.49% and 0.54%, respectively, and the dietary Ca level was fixed at 0.90% for all treatments. The results showed that average daily gain, serum inorganic P concentration, tibia bone strength, tibia ash percentage and P percentage, tibia bone mineral content (BMC) and density (BMD), middle toe ash percentage and P percentage, middle toe BMC, total body BMC and BMD were affected (P<0.0001) by dietary NPP level, and increased linearly (P<0.0001) and quadratically (P<0.003) as dietary NPP levels increased. Optimal dietary NPP levels estimated based on fitted broken-line models (P<0.0001) of the above indices are 0.21%, 0.29%, 0.29%, 0.29%, 0.29%, 0.31%, 0.29%, 0.30%, 0.27%, 0.29% and 0.28%, respectively. It is suggested that the total body BMC and BMD, and middle toe ash P and BMC might be new, sensitive and non-invasive criteria to evaluate the dietary NPP requirements of broilers. The optimal dietary NPP level would be 0.31% for broiler chickens fed a conventional corn-soybean meal diet from 4 to 6 weeks of age.

STAR Algorithm Integration Team - Facilitating operational algorithm development

NASA Astrophysics Data System (ADS)

Mikles, V. J.

2015-12-01

The NOAA/NESDIS Center for Satellite Research and Applications (STAR) provides technical support of the Joint Polar Satellite System (JPSS) algorithm development and integration tasks. Utilizing data from the S-NPP satellite, JPSS generates over thirty Environmental Data Records (EDRs) and Intermediate Products (IPs) spanning atmospheric, ocean, cryosphere, and land weather disciplines. The Algorithm Integration Team (AIT) brings technical expertise and support to product algorithms, specifically in testing and validating science algorithms in a pre-operational environment. The AIT verifies that new and updated algorithms function in the development environment, enforces established software development standards, and ensures that delivered packages are functional and complete. AIT facilitates the development of new JPSS-1 algorithms by implementing a review approach based on the Enterprise Product Lifecycle (EPL) process. Building on relationships established during the S-NPP algorithm development process and coordinating directly with science algorithm developers, the AIT has implemented structured reviews with self-contained document suites. The process has supported algorithm improvements for products such as ozone, active fire, vegetation index, and temperature and moisture profiles.

Suomi NPP VIIRS Ocean Color Data Product Early Mission Assessment

NASA Technical Reports Server (NTRS)

Turpie, Kevin R.; Robinson, Wayne D.; Franz, Bryan A.; Eplee, Robert E., Jr.; Meister, Gerhard; Fireman, Gwyn F.; Patt, Frederick S.; Barnes, Robert A.; McClain, Charles R.

2013-01-01

Following the launch of the Visible Infrared Imaging Radiometer Suite (VIIRS) aboard the Suomi National Polarorbiting Partnership (NPP) spacecraft, the NASA NPP VIIRS Ocean Science Team (VOST) began an evaluation of ocean color data products to determine whether they could continue the existing NASA ocean color climate data record (CDR). The VOST developed an independent evaluation product based on NASA algorithms with a reprocessing capability. Here we present a preliminary assessment of both the operational ocean color data products and the NASA evaluation data products regarding their applicability to NASA science objectives.

Mechanical properties and microstructure of long term thermal aged WWER 440 RPV steel

NASA Astrophysics Data System (ADS)

Kolluri, M.; Kryukov, A.; Magielsen, A. J.; Hähner, P.; Petrosyan, V.; Sevikyan, G.; Szaraz, Z.

2017-04-01

The integrity assessment of the Reactor Pressure Vessel (RPV) is essential for the safe and Long Term Operation (LTO) of a Nuclear Power Plant (NPP). Hardening and embrittlement of RPV caused by neutron irradiation and thermal ageing are main reasons for mechanical properties degradation during the operation of an NPP. The thermal ageing-induced degradation of RPV steels becomes more significant with extended operational lives of NPPs. Consequently, the evaluation of thermal ageing effects is important for the structural integrity assessments required for the lifetime extension of NPPs. As a part of NRG's research programme on Structural Materials for safe-LTO of Light Water Reactor (LWR) RPVs, WWER-440 surveillance specimens, which have been thermal aged for 27 years (∼200,000 h) at 290 °C in a surveillance channel of Armenian-NPP, are investigated. Results from the mechanical and microstructural examination of these thermal aged specimens are presented in this article. The results indicate the absence of significant long term thermal ageing effect of 15Cr2MoV-A steel. No age hardening was detected in aged tensile specimens compared with the as-received condition. There is no difference between the impact properties of as-received and thermal aged weld metals. The upper shelf energy of the aged steel remains the same as for the as-received material at a rather high level of about 120 J. The T41 value did not change and was found to be about 10 °C. The microstructure of thermal aged weld, consisting carbides, carbonitrides and manganese-silicon inclusions, did not change significantly compared to as-received state. Grain-boundary segregation of phosphorus in long term aged weld is not significant either which has been confirmed by the absence of intergranular fracture increase in the weld. Negligible hardening and embrittlement observed after such long term thermal ageing is attributed to the optimum chemical composition of 15Cr2MoV-A for high thermal stability.

The allocation of ecosystem net primary productivity in tropical forests

PubMed Central

Malhi, Yadvinder; Doughty, Christopher; Galbraith, David

2011-01-01

The allocation of the net primary productivity (NPP) of an ecosystem between canopy, woody tissue and fine roots is an important descriptor of the functioning of that ecosystem, and an important feature to correctly represent in terrestrial ecosystem models. Here, we collate and analyse a global dataset of NPP allocation in tropical forests, and compare this with the representation of NPP allocation in 13 terrestrial ecosystem models. On average, the data suggest an equal partitioning of allocation between all three main components (mean 34 ± 6% canopy, 39 ± 10% wood, 27 ± 11% fine roots), but there is substantial site-to-site variation in allocation to woody tissue versus allocation to fine roots. Allocation to canopy (leaves, flowers and fruit) shows much less variance. The mean allocation of the ecosystem models is close to the mean of the data, but the spread is much greater, with several models reporting allocation partitioning outside of the spread of the data. Where all main components of NPP cannot be measured, litterfall is a good predictor of overall NPP (r2 = 0.83 for linear fit forced through origin), stem growth is a moderate predictor and fine root production a poor predictor. Across sites the major component of variation of allocation is a shifting allocation between wood and fine roots, with allocation to the canopy being a relatively invariant component of total NPP. This suggests the dominant allocation trade-off is a ‘fine root versus wood’ trade-off, as opposed to the expected ‘root–shoot’ trade-off; such a trade-off has recently been posited on theoretical grounds for old-growth forest stands. We conclude by discussing the systematic biases in estimates of allocation introduced by missing NPP components, including herbivory, large leaf litter and root exudates production. These biases have a moderate effect on overall carbon allocation estimates, but are smaller than the observed range in allocation values across sites. PMID:22006964

Annual climate variation modifies nitrogen induced carbon accumulation of Pinus sylvestris forests.

PubMed

Lim, Hyungwoo; Oren, Ram; Linder, Sune; From, Fredrik; Nordin, Annika; Fahlvik, Nils; Lundmark, Tomas; Näsholm, Torgny

2017-09-01

We report results from long-term simulated external nitrogen (N) input experiments in three northern Pinus sylvestris forests, two of moderately high and one of moderately low productivity, assessing effects on annual net primary production (NPP) of woody mass and its interannual variation in response to variability in weather conditions. A sigmoidal response of wood NPP to external N inputs was observed in the both higher and lower productivity stands, reaching a maximum of ~65% enhancement regardless of the native site productivity, saturating at an external N input of 4-5 g N·m -2 ·yr -1 . The rate of increase in wood NPP and the N response efficiency (RE N , increase in wood NPP per external N input) were maximized at an external N input of ~3 g N·m -2 ·yr -1 , regardless of site productivity. The maximum RE N was greater in the higher productivity than the lower productivity stand (~20 vs. ~14 g C/g N). The N-induced enhancement of wood NPP and its RE N were, however, markedly contingent on climatic variables. In both of the higher and lower productivity stands, wood NPP increased with growing season precipitation (P), but only up to ~400 mm. The sensitivity of the response to P increased with increasing external N inputs. Increasing growing season temperature (T) somewhat increased the N-induced drought effect, whereas decreasing T reduced the drought effect. These responses of wood NPP infused a large temporal variation to RE N , making the use of a fixed value unadvisable. Based on these results, we suggest that regional climate conditions and future climate scenarios should be considered when modeling carbon sequestration in response to N deposition in boreal P. sylvestris, and possibly other forests. © 2017 by the Ecological Society of America.

Quantifying Human Appropriated Net Primary Productivity (HANPP) in a Ghanaian Cocoa System

NASA Astrophysics Data System (ADS)

Morel, A.; Adu-Bredu, S.; Adu Sasu, M.; Ashley Asare, R.; Boyd, E.; Hirons, M. A.; Malhi, Y.; Mason, J.; Norris, K.; Robinson, E. J. Z.; McDermott, C. L.

2015-12-01

Ghana is the second largest producer of cocoa (Theobroma cacoa), exporting approximately 18 percent of global volumes. These cocoa farms are predominantly small-scale, ranging in size from 2-4 hectares (ha). Traditionally, the model of cocoa expansion in Ghana relied on clearing new areas of forest and establishing a farm under remnant forest trees. This is increasingly less practical due to few unprotected forest areas remaining and management practices favoring close to full sun cocoa to maximize short-term yields. This study is part of a larger project, ECOLMITS, which is an interdisciplinary, ESPA-funded[1] initiative exploring the ecological limits of ecosystem system services (ESS) for alleviating poverty in small-scale agroforestry systems. The ecological study plots are situated within and around the Kakum National Forest, a well-protected, moist-evergreen forest of the Lower Guinea Forest region. Net primary productivity (NPP) is a measure of the rate at which carbon dioxide (CO2) is incorporated into plant tissues (e.g. canopy, stem and root). For this study, NPP was monitored in situ using methods developed by the Global Environmental Monitoring Network (GEM, http://gem.tropicalforests.ox.ac.uk/). By comparing NPP measured in intact forest and farms, the human appropriated NPP (HANPP) of this system can be estimated. The forest measures provide the "potential" NPP of the region, and then the reduction in NPP for farm plots is calculated for both land-cover change (HANPPLUC) and cocoa harvesting (HANPPHARV). The results presented are of the first year of NPP measurements across the cocoa landscape, including measurements from intact forest, logged forest and cocoa farms across a shade gradient and located at varying distances from the forest edge (e.g. 100 m, 500 m, 1 km and 5 km). These measures will have implications for carbon sequestration potential over the region and long-term sustainability of the Ghanaian cocoa sector. [1] Ecosystem Services for Poverty Alleviation grant program, http://www.espa.ac.uk/

MODIS-Derived Terrestrial Primary Production

NASA Astrophysics Data System (ADS)

Zhao, Maosheng; Running, Steven; Heinsch, Faith Ann; Nemani, Ramakrishna

Temporal and spatial changes in terrestrial biological productivity have a large impact on humankind because terrestrial ecosystems not only create environments suitable for human habitation, but also provide materials essential for survival, such as food, fiber and fuel. A recent study estimated that consumption of terrestrial net primary production (NPP; a list of all the acronyms is available in the appendix at the end of the chapter) by the human population accounts for about 14-26% of global NPP (Imhoff et al. 2004). Rapid global climate change is induced by increased atmospheric greenhouse gas concentration, especially CO2, which results from human activities such as fossil fuel combustion and deforestation. This directly impacts terrestrial NPP, which continues to change in both space and time (Melillo et al. 1993; Prentice et al. 2001; Nemani et al. 2003), and ultimately impacts the well-being of human society (Milesi et al. 2005). Additionally, substantial evidence show that the oceans and the biosphere, especially terrestrial ecosystems, currently play a major role in reducing the rate of the atmospheric CO2 increase (Prentice et al. 2001; Schimel et al. 2001). NPP is the first step needed to quantify the amount of atmospheric carbon fixed by plants and accumulated as biomass. Continuous and accurate measurements of terrestrial NPP at the global scale are possible using satellite data. Since early 2000, for the first time, the MODIS sensors onboard the Terra and Aqua satellites, have operationally provided scientists with near real-time global terrestrial gross primary production (GPP) and net photosynthesis (PsnNet) data. These data are provided at 1 km spatial resolution and an 8-day interval, and annual NPP covers 109,782,756 km2 of vegetated land. These GPP, PsnNet and NPP products are collectively known as MOD17 and are part of a larger suite of MODIS land products (Justice et al. 2002), one of the core Earth System or Climate Data Records (ESDR or CDR).

Water-soluble phosphorus in fresh broiler litter is dependent upon phosphorus concentration fed but not on fungal phytase supplementation.

PubMed

Applegate, T J; Joern, B C; Nussbaum-Wagler, D L; Angel, R

2003-06-01

This experiment determined the effects of different phosphorus (P) feeding programs on total and water-soluble P excretion by broilers. Ross 308, male broilers were fed an industry (IND) diet (0.48, 0.35, 0.31, and 0.30% nonphytate P; NPP), an industry diet with reduced NPP and supplemental phytase [IND + PT; 600 phytase units (FTU)/kg; 0.36, 0.26, 0.20, and 0.19% NPP], a diet to more closely meet the birds' NPP requirements in which NPP was reduced further with supplemental phytase (REQ + P; 600 FTU/kg; 0.36, 0.26, 0.19, and 0.09% NPP), or a diet with low-phytate(lpa 1-1) corn with supplemental phytase (LPA + P; 600 FTU/kg; 0.37, 0.29, 0.19, 0.19% NPP). These diets were fed from hatch to 17 d, 17 to 31 d, 31 to 42 d, and 42 to 49 d of age, respectively. Fungal phytase was analyzed prior to diet formulation. Diets were fed to six replicate pens of 39 birds per pen. Litter samples were collected at 49 d of age and frozen prior to analyses. Diet did not significantly affect broiler performance (average BW at 49 d = 3.03 kg), tibia, or toe ash throughout the study (P > 0.05). Litter from broilers fed the IND diet was significantly higher (P < or = 0.05) in total and water-soluble P (1.11 and 0.22% of DM, respectively) compared with litter from broilers fed IND + PT (0.84 and 0.14% of DM, respectively), REQ + P (0.78 and 0.11% of DM, respectively), or LPA + PT (0.64 and 0.12% of DM, respectively). Litter total and water-soluble P were not significantly different among broilers fed IND + PT, REQ + PT, or LPA + PT. In conclusion, phytase supplementation did not affect the solubility of P in the litter regardless of P feeding program.

Accounting for land use in life cycle assessment: The value of NPP as a proxy indicator to assess land use impacts on ecosystems.

PubMed

Taelman, Sue Ellen; Schaubroeck, Thomas; De Meester, Steven; Boone, Lieselot; Dewulf, Jo

2016-04-15

Terrestrial land and its resources are finite, though, for economic and socio-cultural needs of humans, these natural resources are further exploited. It highlights the need to quantify the impact humans possibly have on the environment due to occupation and transformation of land. As a starting point of this paper (1(st) objective), the land use activities, which may be mainly socio-culturally or economically oriented, are identified in addition to the natural land-based processes and stocks and funds that can be altered due to land use. To quantify the possible impact anthropogenic land use can have on the natural environment, linked to a certain product or service, life cycle assessment (LCA) is a tool commonly used. During the last decades, many indicators are developed within the LCA framework in an attempt to evaluate certain environmental impacts of land use. A second objective of this study is to briefly review these indicators and to categorize them according to whether they assess a change in the asset of natural resources for production and consumption or a disturbance of certain ecosystem processes, i.e. ecosystem health. Based on these findings, two enhanced proxy indicators are proposed (3(rd) objective). Both indicators use net primary production (NPP) loss (potential NPP in the absence of humans minus remaining NPP after land use) as a relevant proxy to primarily assess the impact of land use on ecosystem health. As there are two approaches to account for the natural and productive value of the NPP remaining after land use, namely the Human Appropriation of NPP (HANPP) and hemeroby (or naturalness) concepts, two indicators are introduced and the advantages and limitations compared to state-of-the-art NPP-based land use indicators are discussed. Exergy-based spatially differentiated characterization factors (CFs) are calculated for several types of land use (e.g., pasture land, urban land). Copyright © 2016 Elsevier B.V. All rights reserved.

Results of operation and current safety performance of nuclear facilities located in the Russian Federation

NASA Astrophysics Data System (ADS)

Kuznetsov, V. M.; Khvostova, M. S.

2016-12-01

After the NPP radiation accidents in Russia and Japan, a safety statu of Russian nuclear power plants causes concern. A repeated life time extension of power unit reactor plants, designed at the dawn of the nuclear power engineering in the Soviet Union, power augmentation of the plants to 104-109%, operation of power units in a daily power mode in the range of 100-70-100%, the use of untypical for NPP remixed nuclear fuel without a careful study of the results of its application (at least after two operating periods of the research nuclear installations), the aging of operating personnel, and many other management actions of the State Corporation "Rosatom", should attract the attention of the Federal Service for Ecological, Technical and Atomic Supervision (RosTekhNadzor), but this doesn't happen. The paper considers safety issues of nuclear power plants operating in the Russian Federation. The authors collected statistical information on violations in NPP operation over the past 25 years, which shows that even after repeated relaxation over this period of time of safety regulation requirements in nuclear industry and highly expensive NPP modernization, the latter have not become more safe, and the statistics confirms this. At a lower utilization factor high-power pressure-tube reactors RBMK-1000, compared to light water reactors VVER-440 and 1000, have a greater number of violations and that after annual overhauls. A number of direct and root causes of NPP mulfunctions is still high and remains stable for decades. The paper reveals bottlenecks in ensuring nuclear and radiation safety of nuclear facilities. Main outstanding issues on the storage of spent nuclear fuel are defined. Information on emissions and discharges of radioactive substances, as well as fullness of storages of solid and liquid radioactive waste, located at the NPP sites are presented. Russian NPPs stress test results are submitted, as well as data on the coming removal from operation of NPP units is analyzed.

Response of net primary production to land use and land cover change in mainland China since the late 1980s.

PubMed

Li, Jun; Wang, Zhaoli; Lai, Chengguang; Wu, Xiaoqing; Zeng, Zhaoyang; Chen, Xiaohong; Lian, Yanqing

2018-05-19

Land use and land cover patterns in mainland China have substantially changed in the recent decades under the economic reform policies of the government. The terrestrial carbon cycle, particularly the net primary productivity (NPP), has been substantially changed on both local and national scales. With the growing concern over the effects of the terrestrial carbon cycle on global climate changes, the impacts of land use and cover change (LUCC) on NPP need to be understood. In this study, variations in NPP caused by LUCC (e.g., urbanization and conversion of other land use to forest and grassland) in mainland China from the late 1980s to 2015 were evaluated based on land cover datasets and NPPs simulated from the Carnegie-Ames-Stanford Approach model. The results indicate that the national total losses in NPP attributed to urbanization reached 1.695 TgC between the late 1980s and 2015. A large proportion (63.02%) of the total losses was due to the transformation from cropland to urban land. Urban expansion decreased the monthly and total NPPs over southern China, which includes the South China Region, Southwest China Region, and the middle and lower regions of the Yangtze River. However, the total NPP increased in the majority of urbanized areas in Northern China, including the Huang-Huai-Hai Region, Inner Mongolia Region (MGR), Gan-Xin Region (GXR), and Northeast China Region; monthly NPP in GXR and MGR increased throughout the year. By contrast, the conversion to grassland or forestland increased the monthly and total NPPs of Northern China, suggesting that returning to forestland and grassland could increase the carbon sequestration capacity of terrestrial ecosystems in mainland China. Among the sub-regions, the Loess Plateau Region contributed the largest increase in NPP, which was prompted by the conversion to grassland and forestland. Copyright © 2018 Elsevier B.V. All rights reserved.

Convergence of terrestrial plant production across global climate gradients.

PubMed

Michaletz, Sean T; Cheng, Dongliang; Kerkhoff, Andrew J; Enquist, Brian J

2014-08-07

Variation in terrestrial net primary production (NPP) with climate is thought to originate from a direct influence of temperature and precipitation on plant metabolism. However, variation in NPP may also result from an indirect influence of climate by means of plant age, stand biomass, growing season length and local adaptation. To identify the relative importance of direct and indirect climate effects, we extend metabolic scaling theory to link hypothesized climate influences with NPP, and assess hypothesized relationships using a global compilation of ecosystem woody plant biomass and production data. Notably, age and biomass explained most of the variation in production whereas temperature and precipitation explained almost none, suggesting that climate indirectly (not directly) influences production. Furthermore, our theory shows that variation in NPP is characterized by a common scaling relationship, suggesting that global change models can incorporate the mechanisms governing this relationship to improve predictions of future ecosystem function.

A more productive, but different, ocean after mitigation

NASA Astrophysics Data System (ADS)

John, Jasmin G.; Stock, Charles A.; Dunne, John P.

2015-11-01

Reversibility studies suggest a lagged recovery of global mean sea surface temperatures after mitigation, raising the question of whether a similar lag is likely for marine net primary production (NPP). Here we assess NPP reversibility with a mitigation scenario in which projected Representative Concentration Pathway (RCP) 8.5 forcings are applied out to 2100 and then reversed over the course of the following century in a fully coupled carbon-climate Earth System Model. In contrast to the temperature lag, we find a rapid increase in global mean NPP, including an overshoot to values above contemporary means. The enhanced NPP arises from a transient imbalance between the cooling surface ocean and continued warming in subsurface waters, which weakens upper ocean density gradients, resulting in deeper mixing and enhanced surface nitrate. We also find a marine ecosystem regime shift as persistent silicate depletion results in increased prevalence of large, non-diatom phytoplankton.

Algorithm and Software for Calculating Optimal Regimes of the Process Water Supply System at the Kalininskaya NPP{sup 1}

DOE Office of Scientific and Technical Information (OSTI.GOV)

Murav’ev, V. P., E-mail: murval@mail.ru; Kochetkov, A. V.; Glazova, E. G.

An algorithm and software for calculating the optimal operating regimes of the process water supply system at the Kalininskaya NPP are described. The parameters of the optimal regimes are determined for time varying meteorological conditions and condensation loads of the NPP. The optimal flow of the cooling water in the turbines is determined computationally; a regime map with the data on the optimal water consumption distribution between the coolers and displaying the regimes with an admissible heat load on the natural cooling lakes is composed. Optimizing the cooling system for a 4000-MW NPP will make it possible to conserve atmore » least 155,000 MW · h of electricity per year. The procedure developed can be used to optimize the process water supply systems of nuclear and thermal power plants.« less

An Extreme Meteorological Events Analysis For Nuclear Power Plant (NPP) Siting Project at Bangka Island, Indonesia

NASA Astrophysics Data System (ADS)

Septiadi, Deni; S, Yarianto Sugeng B.; Sriyana; Anzhar, Kurnia; Suntoko, Hadi

2018-03-01

The potential sources of meteorological phenomena in Nuclear Power Plant (NPP) area of interest are identified and the extreme values of the possible resulting hazards associated which such phenomena are evaluated to derive the appropriate design bases for the NPP. The appropriate design bases shall be determined according to the Nuclear Energy Regulatory Agency (Bapeten) applicable regulations, which presently do not indicate quantitative criteria for purposes of determining the design bases for meteorological hazards. These meteorological investigations are also carried out to evaluate the regional and site specific meteorological parameters which affect the transport and dispersion of radioactive effluents on the environment of the region around the NPP site. The meteorological hazards are to be monitored and assessed periodically over the lifetime of the plant to ensure that consistency with the design assumptions is maintained throughout the full lifetime of the facility.

Designing a SCADA system simulator for fast breeder reactor

NASA Astrophysics Data System (ADS)

Nugraha, E.; Abdullah, A. G.; Hakim, D. L.

2016-04-01

SCADA (Supervisory Control and Data Acquisition) system simulator is a Human Machine Interface-based software that is able to visualize the process of a plant. This study describes the results of the process of designing a SCADA system simulator that aims to facilitate the operator in monitoring, controlling, handling the alarm, accessing historical data and historical trend in Nuclear Power Plant (NPP) type Fast Breeder Reactor (FBR). This research used simulation to simulate NPP type FBR Kalpakkam in India. This simulator was developed using Wonderware Intouch software 10 and is equipped with main menu, plant overview, area graphics, control display, set point display, alarm system, real-time trending, historical trending and security system. This simulator can properly simulate the principle of energy flow and energy conversion process on NPP type FBR. This SCADA system simulator can be used as training media for NPP type FBR prospective operators.

Direct in situ measurement of Carbon Allocation to Mycorrhizal Fungi in a California Mixed-Conifer Forest

NASA Astrophysics Data System (ADS)

Allen, M.

2012-04-01

Mycorrhizal fungi consume fixed C in ecosystems in exchange for soil resources. We used sensor and observation platforms belowground to quantify belowground dynamics in a California mixed-conifer ecosystem. We directly observed growth and mortality of mycorrhizal fungi in situ on a daily basis using an automated minirhizotron. We measured soil CO2, T and soil moisture at 5-min intervals into the soil profile. These data are coupled with sensors measuring eddy flux of water and CO2, sapflow for water fluxes and C fixation activity, and photographs for leaf phenology. We used DayCent modeling for net primary productivity (NPP) and measured NPP of rhizomorphs, and fungal hyphae. In an arbuscular mycorrhizal (AM) meadow, NPP was 141g/m2/y, with a productivity of fine root NPP of 76.5g C/m2/y, an estimated 10 percent of which is AM fungal C (7.7 g/m2/y). Extramatrical AM hyphal peak standing crop was 4.4g/m2, with a lifespan of 46 days, with active hyphae persisting for 240 days per year. The extramatrical AM fungal hyphal C was 22.9g/m2/y, for a total net allocation to AM fungi of 30.5 C/m2/y, or 22 percent of the estimated NPP. In the ectomycorrhizal (EM) forest, root standing crop (200g C/m2/y) and rhizomorph (2mg C/m2/y) was 33 percent of the NPP (600g C/m2/y). EM fungal hyphae standing crop was 18g/m2/y, with a 48day lifespan, persisting throughout the year, or 59 g C/m2/y. EM root tips and rhizomorph life spans were nearly a year. Assuming that EM fungi represent 40 percent of the fine root EM NPP (of 200g C/m2/y) or 80g C/m2/y, most of the rhizomorph (in the mineral soil) mass being EM (or 2mg C), and 57 percent of the soil fungal NPP or 80 g C/m2/y, then the EM NPP is 139 C/m2/y, or 23 percent of the estimated NPP (600g C/m2/y). As an independent check on the allocation of C, we applied the Hobbie and Hobbie isotopic fractionation d15N model to C allocation. Using d15N of Chantarellus sp. (10.6) and Rhizopogon sp. (9.1), with a leaf d15N of -4.9, we estimated that 35 percent of the plant N came from mycorrhizal fungi, with 16 percent of the NPP -C allocated to EM fungi. This may represent an underestimate, as many EM fungi present on site do not show a measurable d15N value from saprotrophic fungi. The next step is to incorporate hyphal dynamic events into the annual dynamics. We observed no correlation with soil temperature or moisture. In these forests, production of new hyphae occurs between T of 5C and 10C. During this T change, moisture ranges between 20 and 25 percent. Peak mortality occurs between T of 8C to 15C, with soil moisture of 15 to 20 percent. These correspond to the drying and wetting periods in these Mediterranean forests. Small shifts in soil T or soil moisture with global change could have major impacts on C allocation to mycorrhizal fungi which could feed back to plant species composition.

[Projected changes in vegetation net primary productivity of grassland in Inner Mongolia, China during 2011-2050.

PubMed

Guo, Ling Hui; Hao, Cheng Yuan; Wu, Shao Hong; Gao, Jiang Bo; Zhao, Dong Sheng

2016-03-01

In this paper, the CENTURY-based modeling system (complying CENTURY model from a site-based model into spatial model) after being systematically calibrated was used to investigate future climate change under Representative Concentration Pathways Scenario (RCP, 4.5 and 8.5) driven spatio-temporal changes in vegetation net primary productivity (NPP) of Inner Mongolia grassland during 2011-2050. The simulation showed that Inner Mongolia grassland NPP would greatly decrease with a rate of 0.57 g C·m -2 ·a -1 (RCP4.5) and 0.89 g C·m -2 ·a -1 (RCP8.5). NPP of Inner Mongolia grassland appeared to decrease by approximately 11.6% (2020s), 12.0% (2030s) and 18.0% (2040s) under the RCP4.5 in relation to baseline period, while its reduction could be exacerbated as 23.8% (2020s), 21.2% (2030s) and 30.1% (2040s) in the RCP8.5 at the regional scale. In addition, grassland NPP induced by future climate changes varied between different grassland types and times, strongly correlating with climate scenario. Even for the RCP4.5, however, a great majority (89.7%) of the grassland exhibited a decreasing trend in annual NPP, with 15.6% of the area decreasing by more than 20% compared with the baseline term. Therefore, although future precipitation rising could benefit vegetation growth, it might be still not enough to compensate for the negative effect of warming on the NPP of Inner Mongolia grassland, and the sustainable development of grassland resources might face a greater challenge.

Development of Surface-Variable Polymeric Nanoparticles for Drug Delivery to Tumors.

PubMed

Han, Ning; Pang, Liang; Xu, Jun; Hyun, Hyesun; Park, Jinho; Yeo, Yoon

2017-05-01

To develop nanoparticle drug carriers that interact with cells specifically in the mildly acidic tumor microenvironment, we produced polymeric nanoparticles modified with amidated TAT peptide via a simple surface modification method. Two types of core poly(lactic-co-glycolic acid) nanoparticles (NL and NP) were prepared with a phospholipid shell as an optional feature and covered with polydopamine that enabled the conjugation of TAT peptide on the surface. Subsequent treatment with acid anhydrides such as cis-aconitic anhydride (CA) and succinic anhydride (SA) converted amines of lysine residues in TAT peptide to β-carboxylic amides, introducing carboxylic groups that undergo pH-dependent protonation and deprotonation. The nanoparticles modified with amidated TAT peptide (NLpT-CA and NPpT-CA) avoided interactions with LS174T colon cancer cells and J774A.1 macrophages at pH 7.4 but restored the ability to interact with LS174T cells at pH 6.5, delivering paclitaxel efficiently to the cells following a brief contact time. In LS174T tumor-bearing nude mice, NPpT-CA showed less accumulation in the lung than NPpT, reflecting the shielding effect of amidation, but tumor accumulation of NPpT and NPpT-CA was equally minimal. Comparison of particle stability and protein corona formation in media containing sera from different species suggests that NPpT-CA has been activated and opsonized in mouse blood to a greater extent than those in bovine serum-containing medium, thus losing the benefits of pH-sensitivity expected from in vitro experiments.

Reliability ensemble averaging of 21st century projections of terrestrial net primary productivity reduces global and regional uncertainties

NASA Astrophysics Data System (ADS)

Exbrayat, Jean-François; Bloom, A. Anthony; Falloon, Pete; Ito, Akihiko; Smallman, T. Luke; Williams, Mathew

2018-02-01

Multi-model averaging techniques provide opportunities to extract additional information from large ensembles of simulations. In particular, present-day model skill can be used to evaluate their potential performance in future climate simulations. Multi-model averaging methods have been used extensively in climate and hydrological sciences, but they have not been used to constrain projected plant productivity responses to climate change, which is a major uncertainty in Earth system modelling. Here, we use three global observationally orientated estimates of current net primary productivity (NPP) to perform a reliability ensemble averaging (REA) method using 30 global simulations of the 21st century change in NPP based on the Inter-Sectoral Impact Model Intercomparison Project (ISIMIP) business as usual emissions scenario. We find that the three REA methods support an increase in global NPP by the end of the 21st century (2095-2099) compared to 2001-2005, which is 2-3 % stronger than the ensemble ISIMIP mean value of 24.2 Pg C y-1. Using REA also leads to a 45-68 % reduction in the global uncertainty of 21st century NPP projection, which strengthens confidence in the resilience of the CO2 fertilization effect to climate change. This reduction in uncertainty is especially clear for boreal ecosystems although it may be an artefact due to the lack of representation of nutrient limitations on NPP in most models. Conversely, the large uncertainty that remains on the sign of the response of NPP in semi-arid regions points to the need for better observations and model development in these regions.

Assessing the impacts of droughts on net primary productivity in China.

PubMed

Pei, Fengsong; Li, Xia; Liu, Xiaoping; Lao, Chunhua

2013-01-15

Frequency and severity of droughts were projected to increase in many regions. However, their effects of temporal dynamics on the terrestrial carbon cycle remain uncertain, and hence deserve further investigation. In this paper, the droughts that occurred in China during 2001-2010 were identified by using the standardized precipitation index (SPI). Standardized anomaly index (SAI), which has been widely employed in reflecting precipitation, was extended to evaluate the anomalies of net primary productivity (NPP). In addition, influences of the droughts on vegetation were explored by examining the temporal dynamics of SAI-NPP along with area-weighted drought intensity at different time scales (1, 3, 6, 9 and 12 months). Year-to-year variability of NPP with several factors, including droughts, NDVI, radiation and temperature, was analyzed as well. Consequently, the droughts in the years 2001, 2006 and 2009 were well reconstructed. This indicates that SPI could be applied to the monitoring of the droughts in China during the past decade (2001-2010) effectively. Moreover, strongest correlations between droughts and NPP anomalies were found during or after the drought intensities reached their peak values. In addition, some droughts substantially reduced the countrywide NPP, whereas the others did not. These phenomena can be explained by the regional diversities of drought intensity, drought duration, areal extents of the droughts, as well as the cumulative and lag responses of vegetation to the precipitation deficits. Besides the drought conditions, normalized difference vegetation index (NDVI), radiation and temperature also contribute to the interannual variability of NPP. Copyright © 2012 Elsevier Ltd. All rights reserved.

Assessment of Export Efficiency Equations in the Southern Ocean Applied to Satellite-Based Net Primary Production

NASA Astrophysics Data System (ADS)

Arteaga, Lionel; Haëntjens, Nils; Boss, Emmanuel; Johnson, Kenneth S.; Sarmiento, Jorge L.

2018-04-01

Carbon export efficiency (e-ratio) is defined as the fraction of organic carbon fixed through net primary production (NPP) that is exported out of the surface productive layer of the ocean. Recent observations for the Southern Ocean suggest a negative e-ratio versus NPP relationship, and a reduced dependency of export efficiency on temperature, different than in the global domain. In this study, we complement information from a passive satellite sensor with novel space-based lidar observations of ocean particulate backscattering to infer NPP over the entire annual cycle, and estimate Southern Ocean export rates from five different empirical models of export efficiency. Inferred Southern Ocean NPP falls within the range of previous studies, with a mean estimate of 15.8 (± 3.9) Pg C yr-1 for the region south of 30°S during the 2005-2016 period. We find that an export efficiency model that accounts for silica(Si)-ballasting, which is constrained by observations with a negative e-ratio versus NPP relationship, shows the best agreement with in situ-based estimates of annual net community production (annual export of 2.7 ± 0.6 Pg C yr-1 south of 30°S). By contrast, models based on the analysis of global observations with a positive e-ratio versus NPP relationship predict annually integrated export rates that are ˜ 33% higher than the Si-dependent model. Our results suggest that accounting for Si-induced ballasting is important for the estimation of carbon export in the Southern Ocean.

Assessing the effect of human-induced land degradation on ecosystem function in the former homelands of South Africa

NASA Astrophysics Data System (ADS)

Wessels, K. J.; Prince, S. D.

2004-12-01

The communal homelands in north-eastern South Africa, created during the apartheid-era, are widely regarded as severely degraded as a result of human utilization. The impacts of degradation on net primary production (NPP) were studied using a time-series (1985 to 2003) of Advanced Very High Resolution Radiometer (AVHRR) NDVI and modeled NPP data for degraded rangelands identified by the National Land Cover (using Landsat TM imagery) and non-degraded rangelands within the same land capability units (LCUs). The NPP of degraded areas was significantly lower than in non-degraded parts of most of the LCUs and the difference between degraded and non-degraded areas did not diminish in years with high rainfall, although NPP in degraded areas in wet years exceeded that of non-degraded areas in drier years. Thus degraded areas had the same resilience as non-degraded areas. The Rain-Use Efficiency (RUE) of degraded areas (NPP per unit rainfall) was also consistently lower than non-degraded areas. The persistence of the effect on the NPP indicated that the degradation is stable at the time scale of 18 years. These results indicate that, while there has not been a catastrophic reduction in ecosystem function within the former homelands, degradation results in a stable state with reduced productivity and RUE. The results highlight the importance of multi-temporal analyses of ecosystem function to understanding land degradation and illustrate how long time-series of terrestrial data might be used in a national land degradation monitoring system.

An Overview of NPP VIIRS Pre-Launch and On-Orbit Calibration and Characterization

NASA Technical Reports Server (NTRS)

Butler, Jim; Gleason, Jim; Xiong, Jack; Chang, Vincent; Lee, Shih Yan

2011-01-01

NPP Visible Infrared Imaging Radiometer Suite (VIIRS) test program at the instrument and observatory level is complete and has provided an extensive amount of high quality data to enable the assessment of sensor performance.

Maternally derived anti-fibroblast growth factor 23 antibody as new tool to reduce phosphorus requirement of chicks.

PubMed

Ren, Zhouzheng; Bütz, Daniel E; Sand, Jordan M; Cook, Mark E

2017-04-01

Novel means to reduce phosphate input into poultry feeds and increase its retention would preserve world phosphate reserves and reduce environmental impact of poultry production. Here we show that a maternally derived antibody to a fibroblast growth factor-23 (FGF-23) peptide (GMNPPPYS) alleviated phosphorus deficiency in chicks fed low non-phytate phosphorus (nPP) diets. White Leghorn laying hens were vaccinated with either an adjuvant control or the synthetic FGF-23 peptide, and chicks with control or anti-FGF-23 maternal antibodies were fed a diet containing either 0.13 or 0.45% nPP (experiment 1), and 0.20 or 0.45% nPP (experiment 2) for 14 d. In both experiments, decreasing nPP from 0.45 to 0.13 or 0.20% decreased BW gain, G:F, excreta phosphorus, plasma phosphate, and plasma FGF-23 at all time periods examined (nPP main effect, P < 0.05). In experiment 1, chicks with maternal anti-FGF-23 antibody had increased tibiotarsi ash (d 14), and decreased excreta phosphate (d 7, 14) and plasma intact parathyroid hormone (d 7) when compared to chicks with control antibody (antibody main effect, P < 0.05). Mortality (d 7 to 14, 1 to 14), posture scores (d 7, 14) and bone lesion scores (d 14) decreased and plasma phosphate (d 14) increased in anti-FGF-23 chicks fed 0.13% nPP, compared to those with control antibody on the same diet (P < 0.05). In experiment 2, chicks with maternal anti-FGF-23 antibody had increased tibiotarsi ash (d 14), and plasma phosphate (d 14) and 1,25(OH)2D3 (d 14) levels, compared to chicks with control antibody (antibody main effect, P < 0.05). BW gain and G:F were increased in chicks with anti-FGF-23 antibody fed 0.20% nPP, compared to control antibody chicks on the same diet, at all time periods examined (P < 0.05). In conclusion, maternally-derived anti-FGF-23 antibody increased phosphorus retention in chicks fed diets containing either 0.13 or 0.20% nPP and thereby, reduced signs of phosphorus deficiency. © 2016 Poultry Science Association Inc.

Satellite-based Tropical Cyclone Monitoring Capabilities

NASA Astrophysics Data System (ADS)

Hawkins, J.; Richardson, K.; Surratt, M.; Yang, S.; Lee, T. F.; Sampson, C. R.; Solbrig, J.; Kuciauskas, A. P.; Miller, S. D.; Kent, J.

2012-12-01

Satellite remote sensing capabilities to monitor tropical cyclone (TC) location, structure, and intensity have evolved by utilizing a combination of operational and research and development (R&D) sensors. The microwave imagers from the operational Defense Meteorological Satellite Program [Special Sensor Microwave/Imager (SSM/I) and the Special Sensor Microwave Imager Sounder (SSMIS)] form the "base" for structure observations due to their ability to view through upper-level clouds, modest size swaths and ability to capture most storm structure features. The NASA TRMM microwave imager and precipitation radar continue their 15+ yearlong missions in serving the TC warning and research communities. The cessation of NASA's QuikSCAT satellite after more than a decade of service is sorely missed, but India's OceanSat-2 scatterometer is now providing crucial ocean surface wind vectors in addition to the Navy's WindSat ocean surface wind vector retrievals. Another Advanced Scatterometer (ASCAT) onboard EUMETSAT's MetOp-2 satellite is slated for launch soon. Passive microwave imagery has received a much needed boost with the launch of the French/Indian Megha Tropiques imager in September 2011, basically greatly supplementing the very successful NASA TRMM pathfinder with a larger swath and more frequent temporal sampling. While initial data issues have delayed data utilization, current news indicates this data will be available in 2013. Future NASA Global Precipitation Mission (GPM) sensors starting in 2014 will provide enhanced capabilities. Also, the inclusion of the new microwave sounder data from the NPP ATMS (Oct 2011) will assist in mapping TC convective structures. The National Polar orbiting Partnership (NPP) program's VIIRS sensor includes a day night band (DNB) with the capability to view TC cloud structure at night when sufficient lunar illumination exits. Examples highlighting this new capability will be discussed in concert with additional data fusion efforts.

Suomi NPP OMPS limb profiler initial sensor performance assessment

NASA Astrophysics Data System (ADS)

Jaross, Glen; Chen, Grace; Kowitt, Mark; Warner, Jeremy; Xu, Philippe; Kelly, Thomas; Linda, Michael; Flittner, David

2012-11-01

Following the successful launch of the Ozone Mapping and Profiler Suite (OMPS) aboard the Suomi National Polar-orbiting Partnership (NPP) spacecraft, the NASA OMPS Limb team began an evaluation of sensor and data product performance in relation to the original goals for this instrument. Does the sensor design work as well as expected, and can limb scatter measurements by NPP OMPS and successor instruments form the basis for accurate long-term monitoring of ozone vertical profiles? While this paper does not address the latter question, the answer to the former is a qualified Yes given this early stage of the mission.

Seven surefire ways to start a nonphysician practitioner off right.

PubMed

Toth, Cheryl

2014-01-01

With the proper planning and preparation, nonphysician practitioners (NPPs) can improve physician productivity and increase patient access to the practice. A thorough training and orientation program is vital to optimizing the effectiveness and retention of an NPP. An organized approach to understanding payer reimbursement guidelines will ensure that his or her services are documented and billed correctly, and paid appropriately. And proper communication and marketing will go a long way toward building the NPP's patient base. This article offers seven proven ideas for getting an NPP off to a great start in any physician practice.

NASA Sees Severe Weather from Central to Eastern US

NASA Image and Video Library

2017-12-08

Suomi NPP capture this true-color image of the storms over the Midwest and US South on April 30, 2017. This images comes from the Visible Infrared Imaging Radiometer Suite (VIIRS) instrument on @NASA.NPP Credit: NASA/NOAA/NPP/VIIRS NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

Monitoring of Typical Steppe Desertification Based on Time Series of Net Primary Productivity Data

NASA Astrophysics Data System (ADS)

Wang, Hongyan; Li, Qiangzi; Gao, Zhihai

2014-11-01

Monitoring of grassland condition is a basic prerequisite for finding the degradation of a territory under climatic and human pressures leading to desertification. The temporal change in vegetation productivity is a key indicator of grassland degradation. In this paper, taking the Xilin Gol League as a case, the net primary production (NPP) dynamic trends during 2001-2010 were analyzed, with the Mann-Kendall test. In this paper, in the study area where precipitation and NPP has significantly positive correlation, the residual trend method (RESTREND) was used to remove the annual NPP fluctuation caused by rainfall fluctuation and reduce the effect of precipitation on vegetation monitoring indicators. The results showed that An overall strong liner correlation between NPP and precipitation was observed in the Xilin Gol grassland, with 68.52% of the pixels analyzed being significantly correlated (α =0.1). The statistical analysis reveals that the NPP trend estimation generally shows a decreasing trend, with 13.02% of the Xilin Gol grassland being analyzed showing a significant trend (11.47% decrease and 1.55% increase). However, the Xilin Gol grassland desertification was not serious in the past ten years, only 5.16% of the study area where the vegetation productivity was significantly decreases (reducing the effect of precipitation).

Topographical effects of climate dataset and their impacts on the estimation of regional net primary productivity

NASA Astrophysics Data System (ADS)

Sun, L. Qing; Feng, Feng X.

2014-11-01

In this study, we first built and compared two different climate datasets for Wuling mountainous area in 2010, one of which considered topographical effects during the ANUSPLIN interpolation was referred as terrain-based climate dataset, while the other one did not was called ordinary climate dataset. Then, we quantified the topographical effects of climatic inputs on NPP estimation by inputting two different climate datasets to the same ecosystem model, the Boreal Ecosystem Productivity Simulator (BEPS), to evaluate the importance of considering relief when estimating NPP. Finally, we found the primary contributing variables to the topographical effects through a series of experiments given an overall accuracy of the model output for NPP. The results showed that: (1) The terrain-based climate dataset presented more reliable topographic information and had closer agreements with the station dataset than the ordinary climate dataset at successive time series of 365 days in terms of the daily mean values. (2) On average, ordinary climate dataset underestimated NPP by 12.5% compared with terrain-based climate dataset over the whole study area. (3) The primary climate variables contributing to the topographical effects of climatic inputs for Wuling mountainous area were temperatures, which suggest that it is necessary to correct temperature differences for estimating NPP accurately in such a complex terrain.

Ground-based grasslands data to support remote sensing and ecosystem modeling of terrestrial primary production

NASA Technical Reports Server (NTRS)

Olson, R. J.; Scurlock, J. M. O.; Turner, R. S.; Jennings, S. V.

1995-01-01

Estimating terrestrial net primary production (NPP) using remote-sensing tools and ecosystem models requires adequate ground-based measurements for calibration, parameterization, and validation. These data needs were strongly endorsed at a recent meeting of ecosystem modelers organized by the International Geosphere-Biosphere Program's (IGBP's) Data and Information System (DIS) and its Global Analysis, Interpretation, and Modelling (GAIM) Task Force. To meet these needs, a multinational, multiagency project is being coordinated by the IGBP DIS to compile existing NPP data from field sites and to regionalize NPP point estimates to various-sized grid cells. Progress at Oak Ridge National Laboratory (ORNL) on compiling NPP data for grasslands as part of the IGBP DIS data initiative is described. Site data and associated documentation from diverse field studies are being acquired for selected grasslands and are being reviewed for completeness, consistency, and adequacy of documentation, including a description of sampling methods. Data are being compiled in a database with spatial, temporal, and thematic characteristics relevant to remote sensing and global modeling. NPP data are available from the ORNL Distributed Active Archive Center (DAAC) for biogeochemical dynamics. The ORNL DAAC is part of the Earth Observing System Data and Information System, of the US National Aeronautics and Space Administration.

Grassland ecosystem responses to climate change and human activities within the Three-River Headwaters region of China.

PubMed

Han, Ze; Song, Wei; Deng, Xiangzheng; Xu, Xinliang

2018-06-13

The Three-River Headwaters region (TRHR) of China is an important part of the Qinghai-Tibetan Plateau. Although the TRHR is rich in grassland resources, the ecosystem of this area is extremely fragile. Natural and artificial interference have been key to the development of grassland ecosystem spatiotemporal heterogeneity, although the intensity and mode of their influence on ecological processes varies depending on scale; analyses in this area are therefore also scale-dependent. We use multi-scale nested data to analyze the mechanisms underlying the influence of climate change and human activities on grassland net primary productivity (NPP) by applying a multi-level modeling approach. The results of this study show that: (1) The annual grassland NPP of the TRHR has risen in a wavelike pattern over time, increasing by 39.88% overall; (2) Differences of 54.9% and 41.1% in temporal grassland NPP can be attributed to variations between these watersheds as well as county characteristics, and; (3) Although the 'warm and moist' climate trend seen over the course of this study has proved beneficial in enhancing grassland NPP, the rate of increase has tended to be faster in relatively dry and warm regions. Economic development and population growth have both exerted negative impacts on grassland NPP.

The virtual digital nuclear power plant: A modern tool for supporting the lifecycle of VVER-based nuclear power units

NASA Astrophysics Data System (ADS)

Arkadov, G. V.; Zhukavin, A. P.; Kroshilin, A. E.; Parshikov, I. A.; Solov'ev, S. L.; Shishov, A. V.

2014-10-01

The article describes the "Virtual Digital VVER-Based Nuclear Power Plant" computerized system comprising a totality of verified initial data (sets of input data for a model intended for describing the behavior of nuclear power plant (NPP) systems in design and emergency modes of their operation) and a unified system of new-generation computation codes intended for carrying out coordinated computation of the variety of physical processes in the reactor core and NPP equipment. Experiments with the demonstration version of the "Virtual Digital VVER-Based NPP" computerized system has shown that it is in principle possible to set up a unified system of computation codes in a common software environment for carrying out interconnected calculations of various physical phenomena at NPPs constructed according to the standard AES-2006 project. With the full-scale version of the "Virtual Digital VVER-Based NPP" computerized system put in operation, the concerned engineering, design, construction, and operating organizations will have access to all necessary information relating to the NPP power unit project throughout its entire lifecycle. The domestically developed commercial-grade software product set to operate as an independently operating application to the project will bring about additional competitive advantages in the modern market of nuclear power technologies.

Cognitive decision errors and organization vulnerabilities in nuclear power plant safety management: Modeling using the TOGA meta-theory framework

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cappelli, M.; Gadomski, A. M.; Sepiellis, M.

In the field of nuclear power plant (NPP) safety modeling, the perception of the role of socio-cognitive engineering (SCE) is continuously increasing. Today, the focus is especially on the identification of human and organization decisional errors caused by operators and managers under high-risk conditions, as evident by analyzing reports on nuclear incidents occurred in the past. At present, the engineering and social safety requirements need to enlarge their domain of interest in such a way to include all possible losses generating events that could be the consequences of an abnormal state of a NPP. Socio-cognitive modeling of Integrated Nuclear Safetymore » Management (INSM) using the TOGA meta-theory has been discussed during the ICCAP 2011 Conference. In this paper, more detailed aspects of the cognitive decision-making and its possible human errors and organizational vulnerability are presented. The formal TOGA-based network model for cognitive decision-making enables to indicate and analyze nodes and arcs in which plant operators and managers errors may appear. The TOGA's multi-level IPK (Information, Preferences, Knowledge) model of abstract intelligent agents (AIAs) is applied. In the NPP context, super-safety approach is also discussed, by taking under consideration unexpected events and managing them from a systemic perspective. As the nature of human errors depends on the specific properties of the decision-maker and the decisional context of operation, a classification of decision-making using IPK is suggested. Several types of initial situations of decision-making useful for the diagnosis of NPP operators and managers errors are considered. The developed models can be used as a basis for applications to NPP educational or engineering simulators to be used for training the NPP executive staff. (authors)« less

Effects of carbon turnover time on terrestrial ecosystem carbon storage

NASA Astrophysics Data System (ADS)

Yan, Yaner; Zhou, Xuhui; Jiang, Lifeng; Luo, Yiqi

2017-12-01

Carbon (C) turnover time is a key factor in determining C storage capacity in various plant and soil pools as well as terrestrial C sink in a changing climate. However, the effects of C turnover time on ecosystem C storage have not been well explored. In this study, we compared mean C turnover times (MTTs) of ecosystem and soil, examined their variability to climate, and then quantified the spatial variation in ecosystem C storage over time from changes in C turnover time and/or net primary production (NPP). Our results showed that mean ecosystem MTT based on gross primary production (GPP; MTTEC_GPP = Cpool/GPP, 25.0 ± 2.7 years) was shorter than soil MTT (MTTsoil = Csoil/NPP, 35.5 ± 1.2 years) and NPP-based ecosystem MTT (MTTEC_NPP = Cpool/NPP, 50.8 ± 3 years; Cpool and Csoil referred to ecosystem or soil C storage, respectively). On the biome scale, temperature is the best predictor for MTTEC (R2 = 0.77, p < 0.001) and MTTsoil (R2 = 0.68, p < 0.001), while the inclusion of precipitation in the model did not improve the performance of MTTEC (R2 = 0.76, p < 0.001). Ecosystem MTT decreased by approximately 4 years from 1901 to 2011 when only temperature was considered, resulting in a large C release from terrestrial ecosystems. The resultant terrestrial C release caused by the decrease in MTT only accounted for about 13.5 % of that due to the change in NPP uptake (159.3 ± 1.45 vs. 1215.4 ± 11.0 Pg C). However, the larger uncertainties in the spatial variation of MTT than temporal changes could lead to a greater impact on ecosystem C storage, which deserves further study in the future.

A Model-based Approach to Scaling GPP and NPP in Support of MODIS Land Product Validation

NASA Astrophysics Data System (ADS)

Turner, D. P.; Cohen, W. B.; Gower, S. T.; Ritts, W. D.

2003-12-01

Global products from the Earth-orbiting MODIS sensor include land cover, leaf area index (LAI), FPAR, 8-day gross primary production (GPP), and annual net primary production (NPP) at the 1 km spatial resolution. The BigFoot Project was designed specifically to validate MODIS land products, and has initiated ground measurements at 9 sites representing a wide array of vegetation types. An ecosystem process model (Biome-BGC) is used to generate estimates of GPP and NPP for each 5 km x 5 km BigFoot site. Model inputs include land cover and LAI (from Landsat ETM+), daily meteorological data (from a centrally located eddy covariance flux tower), and soil characteristics. Model derived outputs are validated against field-measured NPP and flux tower-derived GPP. The resulting GPP and NPP estimates are then aggregated to the 1 km resolution for direct spatial comparison with corresponding MODIS products. At the high latitude sites (tundra and boreal forest), the MODIS GPP phenology closely tracks the BigFoot GPP, but there is a high bias in the MODIS GPP. In the temperate zone sites, problems with the timing and magnitude of the MODIS FPAR introduce differences in MODIS GPP compared to the validation data at some sites. However, the MODIS LAI/FPAR data are currently being reprocessed (=Collection 4) and new comparisons will be made for 2002. The BigFoot scaling approach permits precise overlap in spatial and temporal resolution between the MODIS products and BigFoot products, and thus permits the evaluation of specific components of the MODIS NPP algorithm. These components include meteorological inputs from the NASA Data Assimilation Office, LAI and FPAR from other MODIS algorithms, and biome-specific parameters for base respiration rate and light use efficiency.

Implementing a Nuclear Power Plant Model for Evaluating Load-Following Capability on a Small Grid

NASA Astrophysics Data System (ADS)

Arda, Samet Egemen

A pressurized water reactor (PWR) nuclear power plant (NPP) model is introduced into Positive Sequence Load Flow (PSLF) software by General Electric in order to evaluate the load-following capability of NPPs. The nuclear steam supply system (NSSS) consists of a reactor core, hot and cold legs, plenums, and a U-tube steam generator. The physical systems listed above are represented by mathematical models utilizing a state variable lumped parameter approach. A steady-state control program for the reactor, and simple turbine and governor models are also developed. Adequacy of the isolated reactor core, the isolated steam generator, and the complete PWR models are tested in Matlab/Simulink and dynamic responses are compared with the test results obtained from the H. B. Robinson NPP. Test results illustrate that the developed models represents the dynamic features of real-physical systems and are capable of predicting responses due to small perturbations of external reactivity and steam valve opening. Subsequently, the NSSS representation is incorporated into PSLF and coupled with built-in excitation system and generator models. Different simulation cases are run when sudden loss of generation occurs in a small power system which includes hydroelectric and natural gas power plants besides the developed PWR NPP. The conclusion is that the NPP can respond to a disturbance in the power system without exceeding any design and safety limits if appropriate operational conditions, such as achieving the NPP turbine control by adjusting the speed of the steam valve, are met. In other words, the NPP can participate in the control of system frequency and improve the overall power system performance.

Trends of Training Courses Conducted in the Human Resources Development Center of the National Institute for Quantum and Radiological Science and Technology After the Fukushima Dai-Ichi Nuclear Power Plant Accident.

PubMed

Shimizu, Yuko; Iida, Haruzo; Nenoi, Mitsuru

2017-07-01

Environmental contamination with radioactive materials caused by the Fukushima Dai-ichi Nuclear Power Plant (NPP) accident in 2011 raised a serious health concern among residents in Japan, and the demand for radiation experts who can handle the radiation-associated problems has increased. The Human Resources Development Center (HRDC) of the National Institute of for Quantum and Radiological Science and Technology in Japan has offered a variety of training programs covering a wide range of technologies associated with radiation since 1959. In this study, the time-course change in the number and age of the applicants for training programs regularly scheduled at HRDC were analyzed to characterize the demand after the NPP accident. The results suggested that the demand for the training of industrial radiation experts elevated sharply after the NPP accident followed by a prompt decrease, and that young people were likely stimulated to learn the basics of radiation. The demand for the training of medical radiation experts was kept high regardless of the NPP accident. The demand for the training of radiation emergency experts fluctuated apparently with three components: a terminating demand after the criticality accident that occurred in 1999, an urgent demand for handling of the NPP accident, and a sustained demand from local governments that undertook reinforcement of their nuclear disaster prevention program. The demand for the training of school students appeared to be increasing after the NPP accident. It could be foreseen that the demand for training programs targeting young people and medical radiation experts would be elevated in future.

Fire intensity impacts on post-fire temperate coniferous forest net primary productivity

NASA Astrophysics Data System (ADS)

Sparks, Aaron M.; Kolden, Crystal A.; Smith, Alistair M. S.; Boschetti, Luigi; Johnson, Daniel M.; Cochrane, Mark A.

2018-02-01

Fire is a dynamic ecological process in forests and impacts the carbon (C) cycle through direct combustion emissions, tree mortality, and by impairing the ability of surviving trees to sequester carbon. While studies on young trees have demonstrated that fire intensity is a determinant of post-fire net primary productivity, wildland fires on landscape to regional scales have largely been assumed to either cause tree mortality, or conversely, cause no physiological impact, ignoring the impacted but surviving trees. Our objective was to understand how fire intensity affects post-fire net primary productivity in conifer-dominated forested ecosystems on the spatial scale of large wildland fires. We examined the relationships between fire radiative power (FRP), its temporal integral (fire radiative energy - FRE), and net primary productivity (NPP) using 16 years of data from the MOderate Resolution Imaging Spectrometer (MODIS) for 15 large fires in western United States coniferous forests. The greatest NPP post-fire loss occurred 1 year post-fire and ranged from -67 to -312 g C m-2 yr-1 (-13 to -54 %) across all fires. Forests dominated by fire-resistant species (species that typically survive low-intensity fires) experienced the lowest relative NPP reductions compared to forests with less resistant species. Post-fire NPP in forests that were dominated by fire-susceptible species were not as sensitive to FRP or FRE, indicating that NPP in these forests may be reduced to similar levels regardless of fire intensity. Conversely, post-fire NPP in forests dominated by fire-resistant and mixed species decreased with increasing FRP or FRE. In some cases, this dose-response relationship persisted for more than a decade post-fire, highlighting a legacy effect of fire intensity on post-fire C dynamics in these forests.

GaAs homojunction solar cell development

NASA Technical Reports Server (NTRS)

Flood, D. J.; Swartz, C. K.; Hart, R. E., Jr.

1980-01-01

The Lincoln Laboratory n(+)/p/p(+) GaAs shallow homojunction cell structure was successfully demonstrated on 2 by 2 cm GaAs substrates. Air mass zero efficiencies of the seven cells produced to date range from 13.6 to 15.6 percent. Current voltage (I-V) characteristics, spectral response, and measurements were made on all seven cells. Preliminary analysis of 1 MeV electron radiation damage data indicate excellent radiation resistance for these cells.

Technical Basis and Implementation Guidelines for a Technique for Human Event Analysis (ATHEANA)

DTIC Science & Technology

2000-05-01

posted at NRC’s Web site address www.nrc.gov/NRC/NUREGS/indexnum.html are updated regularly and may differ from the last printed version. Non-NRC...distinctly different in that it provides structured search schemes for finding such EFCs, by using and integrating knowledge and experience in...Learned from Serious Accidents The record of significant incidents in nuclear power plant NPP operations shows a substantially different picture of

Reducing the uncertainty of parameters controlling seasonal carbon and water fluxes in Chinese forests and its implication for simulated climate sensitivities

NASA Astrophysics Data System (ADS)

Li, Yue; Yang, Hui; Wang, Tao; MacBean, Natasha; Bacour, Cédric; Ciais, Philippe; Zhang, Yiping; Zhou, Guangsheng; Piao, Shilong

2017-08-01

Reducing parameter uncertainty of process-based terrestrial ecosystem models (TEMs) is one of the primary targets for accurately estimating carbon budgets and predicting ecosystem responses to climate change. However, parameters in TEMs are rarely constrained by observations from Chinese forest ecosystems, which are important carbon sink over the northern hemispheric land. In this study, eddy covariance data from six forest sites in China are used to optimize parameters of the ORganizing Carbon and Hydrology In Dynamics EcosystEms TEM. The model-data assimilation through parameter optimization largely reduces the prior model errors and improves the simulated seasonal cycle and summer diurnal cycle of net ecosystem exchange, latent heat fluxes, and gross primary production and ecosystem respiration. Climate change experiments based on the optimized model are deployed to indicate that forest net primary production (NPP) is suppressed in response to warming in the southern China but stimulated in the northeastern China. Altered precipitation has an asymmetric impact on forest NPP at sites in water-limited regions, with the optimization-induced reduction in response of NPP to precipitation decline being as large as 61% at a deciduous broadleaf forest site. We find that seasonal optimization alters forest carbon cycle responses to environmental change, with the parameter optimization consistently reducing the simulated positive response of heterotrophic respiration to warming. Evaluations from independent observations suggest that improving model structure still matters most for long-term carbon stock and its changes, in particular, nutrient- and age-related changes of photosynthetic rates, carbon allocation, and tree mortality.

Net carbon exchange across the Arctic tundra-boreal forest transition in Alaska 1981-2000

USGS Publications Warehouse

Thompson, Catharine Copass; McGuire, A.D.; Clein, Joy S.; Chapin, F. S.; Beringer, J.

2006-01-01

Shifts in the carbon balance of high-latitude ecosystems could result from differential responses of vegetation and soil processes to changing moisture and temperature regimes and to a lengthening of the growing season. Although shrub expansion and northward movement of treeline should increase carbon inputs, the effects of these vegetation changes on net carbon exchange have not been evaluated. We selected low shrub, tall shrub, and forest tundra sites near treeline in northwestern Alaska, representing the major structural transitions expected in response to warming. In these sites, we measured aboveground net primary production (ANPP) and vegetation and soil carbon and nitrogen pools, and used these data to parameterize the Terrestrial Ecosystem Model. We simulated the response of carbon balance components to air temperature and precipitation trends during 1981-2000. In areas experiencing warmer and dryer conditions, Net Primary Production (NPP) decreased and heterotrophic respiration (R H ) increased, leading to a decrease in Net Ecosystem Production (NEP). In warmer and wetter conditions NPP increased, but the response was exceeded by an increase in R H ; therefore, NEP also decreased. Lastly, in colder and wetter regions, the increase in NPP exceeded a small decline in R H , leading to an increase in NEP. The net effect for the region was a slight gain in ecosystem carbon storage over the 20 year period. This research highlights the potential importance of spatial variability in ecosystem responses to climate change in assessing the response of carbon storage in northern Alaska over the last two decades. ?? Springer 2005.

Distribution of radionuclides in a marine sediment core off the waterspout of the nuclear power plants in Daya Bay, northeastern South China Sea.

PubMed

Zhou, Peng; Li, Dongmei; Li, Haitao; Fang, Hongda; Huang, Chuguang; Zhang, Yusheng; Zhang, Hongbiao; Zhao, Li; Zhou, Junjie; Wang, Hua; Yang, Jie

2015-07-01

A sediment core was collected and dated using (210)Pbex dating method off the waterspout of nuclear power base of Daya Bay, northeastern South China Sea. The γ-emitting radionuclides were analyzed using HPGe γ spectrometry, gross alpha and beta radioactivity as well as other geochemical indicators were deliberated to assess the impact of nuclear power plants (NPP) operation and to study the past environment changes. It suggested that NPP provided no new radioactivity source to sediment based on the low specific activity of (137)Cs. Two broad peaks of TOC, TC and LOI accorded well with the commercial operations of Daya Bay NPP (1994.2 and 1994.5) and LNPP Phase I (2002.5 and 2003.3), implying that the mass input of cooling water from NPP may result into a substantial change in the ecological environment and Daya Bay has been severely impacted by human activities. Copyright © 2015 Elsevier Ltd. All rights reserved.

MODIS EVI-based net primary production in the Sahel 2000-2014

NASA Astrophysics Data System (ADS)

Ardö, Jonas; Tagesson, Torbern; Jamali, Sadegh; Khatir, Abdelrahman

2018-03-01

Africa is facing resource problems due to increasing demand combined with potential climate-induced changes in supply. Here we aim to quantify resources in terms of net primary production (NPP [g C m-2 yr-1]) of vegetation in the Sahel region for 2000-2014. Using time series of the enhanced vegetation index (EVI) from MODIS, NPP was estimated for the Sahel region with a 500 × 500 m spatial resolution and 8-day temporal resolution. The estimates were based on local eddy covariance flux measurements from six sites in the Sahel region and the carbon use efficiency originating from a dynamic vegetation model. No significant NPP change was found for the Sahel as a region but, for sub-regions, significant changes, both increasing and decreasing, were observed. Substantial uncertainties related to NPP estimates and the small availability of evaluation data makes verification difficult. The simplicity of the methodology used, dependent on earth observation only, is considered an advantage.

Biome-specific scaling of ocean productivity, temperature, and carbon export efficiency

NASA Astrophysics Data System (ADS)

Britten, Gregory L.; Primeau, François W.

2016-05-01

Mass conservation and metabolic theory place constraints on how marine export production (EP) scales with net primary productivity (NPP) and sea surface temperature (SST); however, little is empirically known about how these relationships vary across ecologically distinct ocean biomes. Here we compiled in situ observations of EP, NPP, and SST and used statistical model selection theory to demonstrate significant biome-specific scaling relationships among these variables. Multiple statistically similar models yield a threefold variation in the globally integrated carbon flux (~4-12 Pg C yr-1) when applied to climatological satellite-derived NPP and SST. Simulated NPP and SST input variables from a 4×CO2 climate model experiment further show that biome-specific scaling alters the predicted response of EP to simulated increases of atmospheric CO2. These results highlight the need to better understand distinct pathways of carbon export across unique ecological biomes and may help guide proposed efforts for in situ observations of the ocean carbon cycle.

Agricultural conversion without external water and nutrient inputs reduces terrestrial vegetation productivity

USGS Publications Warehouse

Smith, W. Kolby; Cleveland, Cory C.; Reed, Sasha C.; Running, Steven W.

2014-01-01

Driven by global population and standard of living increases, humanity co-opts a growing share of the planet's natural resources resulting in many well-known environmental trade-offs. In this study, we explored the impact of agriculture on a resource fundamental to life on Earth: terrestrial vegetation growth (net primary production; NPP). We demonstrate that agricultural conversion has reduced terrestrial NPP by ~7.0%. Increases in NPP due to agricultural conversion were observed only in areas receiving external inputs (i.e., irrigation and/or fertilization). NPP reductions were found for ~88% of agricultural lands, with the largest reductions observed in areas formerly occupied by tropical forests and savannas (~71% and ~66% reductions, respectively). Without policies that explicitly consider the impact of agricultural conversion on primary production, future demand-driven increases in agricultural output will likely continue to drive net declines in global terrestrial productivity, with potential detrimental consequences for net ecosystem carbon storage and subsequent climate warming.

Contrasting responses of shrubland carbon gain and soil carbon efflux to drought and warming across a European climate gradient

NASA Astrophysics Data System (ADS)

Reinsch, Sabine; Koller, Eva; Sowerby, Alwyn; de Dato, Giovanbattista; Estiarte, Marc; Guidolotti, Gabriele; Kovács-Láng, Edit; Kröel-Dulay, György; Lellei-Kovács, Eszter; Larsen, Klaus S.; Liberati, Dario; Penuelas, Josep; Ransijn, Johannes; Schmidt, Inger K.; Smith, Andrew R.; Tietema, Albert; Dukes, Jeffrey S.; Emmett, Bridget A.

2016-04-01

Understanding the relationship between above- and belowground processes is crucial if we are to forecast feedbacks between terrestrial carbon (C) dynamics and future climate. To test if climate-induced changes in annual aboveground net primary productivity (aNPP) will drive changes in C loss by soil respiration (Rs), we integrated data across a European temperature and precipitation gradient. For over a decade, six European shrublands were exposed to repeated drought (-30 % annual rain) during the plants' growth season or year-round night-time warming (+1.5 oC), using an identical experimental approach. As a result, drought reduced ecosystem C gain via aNPP by 0-25 % (compared to an untreated control) with the lowest C gain in warm-dry sites and highest in wet-cold sites (R2=0.078, p-value = 0.544, slope = 14.35 %). In contrast, drought induced C loss via Rs was of a lower magnitude (10-20 %) and was most pronounced in warm-dry sites compared to wet-cold sites (R2=0.687, p-value = 0.131, slope = 7.86 %). This suggests that belowground activity (microbes and roots) is stabilizing ecosystem processes and functions in terms of C storage. However, when the drought treatment permanently altered the soil structure at our hydric site, indicating we had exceeded the resilience of the system, the ecosystem C gain was no longer predictable from current (linear) relationships. Results from the warming treatment were generally of lower magnitude and of opposing direction compared to the drought treatment, indicating different mechanisms were driving ecosystem responses. Overall, our results suggest that aNPP is less sensitive than Rs to climate stresses and soil respiration C fluxes are not predictable from changes in plant productivity. Drought and warming effects on aNPP and Rs did not weaken over decadal timescales at larger, continental scales if no catastrophic threshold is passed. However, indirect effects of climate change on soil properties and/or microbial communities need to be further explored

Chernobyl NPP: Completion of LRW Treatment Plant and LRW Management on Site - 12568

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fedorov, Denis; Adamovich, Dmitry; Klimenko, I.

2012-07-01

Since a beginning of ChNPP operation, and after a tragedy in 1986, a few thousands m3 of LRW have been collected in a storage tanks. In 2004 ChNPP started the new project on creation of LRW treatment plant (LRWTP) financed from EBRD fund. But it was stopped in 2008 because of financial and contract problems. In 2010 SIA RADON jointly with Ukrainian partners has won a tender on completion of LRWTP, in particular I and C system. The purpose of LRTP is to process liquid rad-wastes from SSE 'Chernobyl NPP' site and those liquids stored in the LRWS and SLRWSmore » tanks as well as the would-be wastes after ChNPP Power Units 1, 2 and 3 decommissioning. The LRTP design lifetime - 20 years. Currently, the LRTP is getting ready to perform the following activities: 1. retrieval of waste from tanks stored at ChNPP LWS using waste retrieval system with existing equipment involved; 2. transfer of retrieved waste into LRTP reception tanks with partial use of existing transfer pipelines; 3. laboratory chemical and radiochemical analysis of reception tanks contest to define the full spectrum of characteristics before processing, to acknowledge the necessity of preliminary processing and to select end product recipe; 4. preliminary processing of the waste to meet the requirements for further stages of the process; 5. shrinkage (concentrating) of preliminary processed waste; 6. solidification of preliminary processed waste with concrete to make a solid-state (end product) and load of concrete compound into 200-l drums; 7. curing of end product drums in LRTP curing hall; 8. radiologic monitoring of end product drums and their loading into special overpacks; 9. overpack radiological monitoring; 10. send for disposal (ICSRM Lot 3); The current technical decisions allow to control and return to ChNPP of process media and supporting systems outputs until they satisfy the following quality norms: salt content: < 100 g/l; pH: 1 - 11; anionic surface-active agent: < 25 mg/l; oil dissipated in the liquid: < 2 mg/l; overall gamma-activity: < 3,7 x10{sup 5} Bq/l. (authors)« less

Climate Change Response of Ocean Net Primary Production (NPP) and Export Production (EP) Regulated by Stratification Increases in The CMIP5 models

NASA Astrophysics Data System (ADS)

Fu, W.; Randerson, J. T.; Moore, J. K.

2014-12-01

Ocean warming due to rising atmospheric CO2 has increasing impacts on ocean ecosystems by modifying the ecophysiology and distribution of marine organisms, and by altering ocean circulation and stratification. We explore ocean NPP and EP changes at the global scale with simulations performed in the framework of the fifth Coupled Model Inter-comparison Project (CMIP5). Global NPP and EP are reduced considerably by the end of the century for the representative concentration pathway (RCP) 8.5 scenario, although models differ in their significantly in their direct temperature impacts on production and remineralization. The Earth system models used here project similar NPP trends albeit the magnitudes vary substantially. In general, projected changes in the 2090s for NPP range between -2.3 to -16.2% while export production reach -7 to -18% relative to 1990s. This is accompanied by increased stratification by 17-30%. Results indicate that globally reduced NPP is closely related to increased ocean stratification (R2=0.78). This is especially the case for global export production, that seems to be mostly controlled by the increased stratification (R2=0.95). We also identify phytoplankton community impacts on these patterns, that vary across the models. The negative response of NPP to climate change may be through bottom-up control, leading to a reduced capacity of oceans to regulate climate through the biological carbon pump. There are large disagreements among the CMIP5 models in terms of simulated nutrient and oxygen concentrations for the 1990s, and their trends over time with climate change. In addition, potentially important marine biogeochemical feedbacks on the climate system were not well represented in the CMIP5 models, including important feedbacks with aerosol deposition and the marine iron cycle, and feedbacks involving the oxygen minimum zones and the marine nitrogen cycle. Thus, these substantial reductions in primary productivity and export production over the 21st century simulated under the RCP 8.5 scenario were likely conservative estimates, and may need to be revised as marine biogeochemistry in Earth System Models (ESMs) continues to be developed.

Comparative efficacy of ways of long-term usage of start-up boilers in the scheme of nuclear power plant

NASA Astrophysics Data System (ADS)

Khroustalev, V. A.; Simonyan, A. A.

2017-11-01

There was carried out an analysis of technical characteristics of boiler houses in a number of Russian NPPs. We justified the possibility of their usage for autonomous generation of electrical energy and improvement of maneuvering properties of power complexes as a single object of regulation, as well as the possibility of increasing the total generation capacity of NPP power units during peak hours. Then the selection of the main equipment of house boiler for its autonomous work was done. There were composed basic thermal diagrams of the power complex on the basis of NPP start-up boiler (SUB) and the satellite turbine. The article also considers some options of reconstruction of SUB into the heat-recovery boiler. The developed power complexes are designed to be used on the basis of the two-loop NPP with pressurized power reactors (PWR). They can be applied with serial and projected domestic NPP units with the aim of getting more power, improving the plant capacity factor (PCF), as well as with the aim of NPP participation in the regulation of the load curve above the nominal value with partial replacement of new construction. The power complexes can be a relevant solution in the light of the energy strategy of the Russian Federation, which is aimed at, firstly, further improvement of efficiency and safety at the NPP, and, secondly, solving the problem of adequate maneuverability and ensuring the adjustment range limits in power systems with high share of nuclear power plants. Implementation of new hybrid thermal diagrams allows simultaneous increase in the safety of NPP, and usage of nuclear power plants emergency frequency control in power systems by fast load drop and rise by -4÷+2 % of the nominal value. Due to the usage of different fuels in power complexes, uranium loading in the core of reactor facilities and gas in SUB, there was proposed and formalized the criterion of “thermoeconomic index”. This criterion represents the ratio of the gross receipt from the sale of electricity to the total cost of fuel of all kinds, spent on ensuring power efficiency.

Assessment extreme hydrometeorological conditions in the Gulf of Bothnia, the Baltic Sea

NASA Astrophysics Data System (ADS)

Dvornikov, Anton; Martyanov, Stanislav; Ryabchenko, Vladimir; Eremina, Tatjana; Isaev, Alexey; Sein, Dmitry

2017-04-01

Extreme hydrometeorological conditions in the Gulf of Bothnia, the Baltic Sea, are estimated paying a special attention to the area of the future construction of nuclear power plant (NPP) "Hanhikivi-1" (24° 16' E, 64° 32' N). To produce these estimates, long-term observations and results from numerical models of water and ice circulation and wind waves are used. It is estimated that the average annual air temperature in the vicinity of the station is +3° C, summer and winter extreme temperature is equal to 33.3° C and -41.5° C, respectively. Model calculations of wind waves have shown that the most dangerous (in terms of the generation of wind waves in the NPP area) is a north-west wind with the direction of 310°. The maximum height of the waves in the Gulf of Bothnia near the NPP for this wind direction with wind velocity of 10 m/s is 1.2-1.4 m. According to the model estimates, the highest possible level of the sea near the NPP is 248 cm, the minimum level, -151 cm, respectively for the western and eastern winds. These estimates are in good agreement with observations on the sea level for the period 1922-2015 at the nearest hydrometeorological station Raahe (Finland). In order to assess the likely impact of the NPP on the marine environment numerical experiments for the cold (2010) and warm year (2014) have been carried out. These calculations have shown that permanent release of heat into the marine environment from the operating NPP for the cold year (2010) will increase the temperature in the upper layer of 0-250m zone by 10°C in winter - spring and by 8°C in summer - early autumn, and in the bottom layer of 0-250m zone by 5°C in winter - spring and 3°C in summer - early autumn. For the warm year (2014), these temperature changes are smaller. Ice cover in both cases will disappear in two - kilometer vicinity of the NPP. These effects should be taken into account when assessing local climate changes in the future

VIIRS Product Evaluation at the Ocean PEATE

NASA Technical Reports Server (NTRS)

Patt, Frederick S.; Feldman, Gene C.

2010-01-01

The National Polar-orbiting Operational Environmental Satellite System (NPOESS) Preparatory Project (NPP) mission will support the continuation of climate records generated from NASA missions. The NASA Science Data Segment (SDS) relies upon discipline-specific centers of expertise to evaluate the NPP data products for suitability as climate data records, The Ocean Product Evaluation and Analysis Tool Element (PEATE) will build upon Well established NASA capabilities within the Ocean Color program in order to evaluate the NPP Visible and Infrared Imager/Radiometer Suite (VIIRS) Ocean Color and Chlorophyll data products. The specific evaluation methods will support not only the evaluation of product quality but also the sources of differences with existing data records.

Causes and implications of the correlation between forest productivity and tree mortality rates

USGS Publications Warehouse

Stephenson, Nathan L.; van Mantgem, Philip J.; Bunn, Andrew G.; Bruner, Howard; Harmon, Mark E.; O'Connell, Kari B.; Urban, Dean L.; Franklin, Jerry F.

2011-01-01

For only one of these four mechanisms, competition, can high mortality rates be considered to be a relatively direct consequence of high NPP. The remaining mechanisms force us to adopt a different view of causality, in which tree growth rates and probability of mortality can vary with at least a degree of independence along productivity gradients. In many cases, rather than being a direct cause of high mortality rates, NPP may remain high in spite of high mortality rates. The independent influence of plant enemies and other factors helps explain why forest biomass can show little correlation, or even negative correlation, with forest NPP.

Nonlinear Time Domain Seismic Soil-Structure Interaction (SSI) Deep Soil Site Methodology Development

DOE Office of Scientific and Technical Information (OSTI.GOV)

Spears, Robert Edward; Coleman, Justin Leigh

Currently the Department of Energy (DOE) and the nuclear industry perform seismic soil-structure interaction (SSI) analysis using equivalent linear numerical analysis tools. For lower levels of ground motion, these tools should produce reasonable in-structure response values for evaluation of existing and new facilities. For larger levels of ground motion these tools likely overestimate the in-structure response (and therefore structural demand) since they do not consider geometric nonlinearities (such as gaping and sliding between the soil and structure) and are limited in the ability to model nonlinear soil behavior. The current equivalent linear SSI (SASSI) analysis approach either joins the soilmore » and structure together in both tension and compression or releases the soil from the structure for both tension and compression. It also makes linear approximations for material nonlinearities and generalizes energy absorption with viscous damping. This produces the potential for inaccurately establishing where the structural concerns exist and/or inaccurately establishing the amplitude of the in-structure responses. Seismic hazard curves at nuclear facilities have continued to increase over the years as more information has been developed on seismic sources (i.e. faults), additional information gathered on seismic events, and additional research performed to determine local site effects. Seismic hazard curves are used to develop design basis earthquakes (DBE) that are used to evaluate nuclear facility response. As the seismic hazard curves increase, the input ground motions (DBE’s) used to numerically evaluation nuclear facility response increase causing larger in-structure response. As ground motions increase so does the importance of including nonlinear effects in numerical SSI models. To include material nonlinearity in the soil and geometric nonlinearity using contact (gaping and sliding) it is necessary to develop a nonlinear time domain methodology. This methodology will be known as, NonLinear Soil-Structure Interaction (NLSSI). In general NLSSI analysis should provide a more accurate representation of the seismic demands on nuclear facilities their systems and components. INL, in collaboration with a Nuclear Power Plant Vender (NPP-V), will develop a generic Nuclear Power Plant (NPP) structural design to be used in development of the methodology and for comparison with SASSI. This generic NPP design has been evaluated for the INL soil site because of the ease of access and quality of the site specific data. It is now being evaluated for a second site at Vogtle which is located approximately 15 miles East-Northeast of Waynesboro, Georgia and adjacent to Savanna River. The Vogtle site consists of many soil layers spanning down to a depth of 1058 feet. The reason that two soil sites are chosen is to demonstrate the methodology across multiple soil sites. The project will drive the models (soil and structure) using successively increasing acceleration time histories with amplitudes. The models will be run in time domain codes such as ABAQUS, LS-DYNA, and/or ESSI and compared with the same models run in SASSI. The project is focused on developing and documenting a method for performing time domain, non-linear seismic soil structure interaction (SSI) analysis. Development of this method will provide the Department of Energy (DOE) and industry with another tool to perform seismic SSI analysis.« less

Update of the tectonic model for the Pannonian basin: a contribution to the seismic hazard reassessment of the Paks NPP (Hungary)

NASA Astrophysics Data System (ADS)

Horváth, Ferenc; Tóth, Tamás; Wórum, Géza; Koroknai, Balázs; Kádi, Zoltán; Kovács, Gábor; Balázs, Attila; Visnovitz, Ferenc

2015-04-01

The planned construction of two new units at the site of the Paks NPP requires a comprehensive site investigation including complete reassessment of the seismic hazard according to the Hungarian as well as international standards. Following the regulations of the Specific Safety Guide no. 9 (IAEA 2010), the approved Hungarian Geological Investigation Program (HGIP) includes integrated geological-geophysical studies at different scales. The regional study aims at to elaborate a new synthesis of all published data for the whole Pannonian basin. This task is nearly completed and the main outcomes have already been published (Horváth et al. 2015). The near regional study is in progress and addresses the construction of a new tectonic model for the circular area with 50 km radius around the NPP using a wealth of unpublished oil company seismic and borehole data. The site vicinity study has also been started with a core activity of 300 km² 3D seismic data acquisition, processing and interpretation assisted by a series of additional geophysical surveys, new drillings and geological mapping. This lecture will present a few important results of the near regional study, which sheds new light on the intricate tectonic evolution of the Mid-Hungarian Fault Zone (MHFZ), which is a strongly deformed belt between the Alcapa and Tisza-Dacia megatectonic units. The nuclear power plant is located at the margin of the Tisza unit near to the southern edge of the MHFZ. Reassessment of seismic hazard at the site of the NPP requires better understanding of the Miocene to Recent tectonic evolution of this region in the central part of the Pannonian basin. Early to Middle Miocene was a period of rifting with formation of 1 to 3 km deep half-grabens filled with terrestrial to marine deposits and large amount of rift-related volcanic material. Graben fill became strongly deformed as a consequence of juxtaposition of the two megatectonic units leading to strong compression and development of large scale transfer faults due to differential movements. The beginning of Late Miocene saw an event of basin inversion resulting in uplift and remarkable erosion of the synrift strata. Pliocene through Quaternary has been a period of gradual change in the regional stress field and formation of a series of basin-scale sinistral strike-slip faults usually by reactivation of half-graben bounding normal faults. A most important subject of the HGIP for seismic hazard assessment of the Paks NPP is to determine the timing and amount of displacement of this fault system, as well as its potential capability in the vicinity of the site. References: IAEA (2010): Seismic hazard in site evaluation for nuclear installations. International Atomic Energy Agency Safety Standards, SSG-9, Vienna, p. 60. Horváth, F. et al (2015): Evolution of the Pannonian basin and its geothermal resources. Geothermics, 53, 328-352.

Emerging Environmental Justice Issues in Nuclear Power and Radioactive Contamination

PubMed Central

Kyne, Dean; Bolin, Bob

2016-01-01

Nuclear hazards, linked to both U.S. weapons programs and civilian nuclear power, pose substantial environment justice issues. Nuclear power plant (NPP) reactors produce low-level ionizing radiation, high level nuclear waste, and are subject to catastrophic contamination events. Justice concerns include plant locations and the large potentially exposed populations, as well as issues in siting, nuclear safety, and barriers to public participation. Other justice issues relate to extensive contamination in the U.S. nuclear weapons complex, and the mining and processing industries that have supported it. To approach the topic, first we discuss distributional justice issues of NPP sites in the U.S. and related procedural injustices in siting, operation, and emergency preparedness. Then we discuss justice concerns involving the U.S. nuclear weapons complex and the ways that uranium mining, processing, and weapons development have affected those living downwind, including a substantial American Indian population. Next we examine the problem of high-level nuclear waste and the risk implications of the lack of secure long-term storage. The handling and deposition of toxic nuclear wastes pose new transgenerational justice issues of unprecedented duration, in comparison to any other industry. Finally, we discuss the persistent risks of nuclear technologies and renewable energy alternatives. PMID:27420080

The Test Validation Summary

ERIC Educational Resources Information Center

Frederick, Richard I.; Bowden, Stephen C.

2009-01-01

Common rates employed in classificatory testing are the true positive rate (TPR), false positive rate (FPR), positive predictive power (PPP), and negative predictive power (NPP). FPR and TPR are estimated from research samples representing populations to be distinguished by classificatory testing. PPP and NPP are used by clinicians to classify…

Aboveground and belowground net primary production

Treesearch

Hal O. Liechty; Mark H. Eisenbies

2000-01-01

The relationship among net primary productivity (NPP), hydroperiod, and fertility in forested wetlands is poorly understood (Burke and others 1999), particularly with respect to belowground NPP (Megonigal and others 1997). Although some researchers have studied aboveground and belowground primary production in depressional, forested wetland systems, e.g., Day and...

A metabolism-based whole lake eutrophication model to estimate the magnitude and time scales of the effects of restoration in Upper Klamath Lake, south-central Oregon

USGS Publications Warehouse

Wherry, Susan A.; Wood, Tamara M.

2018-04-27

A whole lake eutrophication (WLE) model approach for phosphorus and cyanobacterial biomass in Upper Klamath Lake, south-central Oregon, is presented here. The model is a successor to a previous model developed to inform a Total Maximum Daily Load (TMDL) for phosphorus in the lake, but is based on net primary production (NPP), which can be calculated from dissolved oxygen, rather than scaling up a small-scale description of cyanobacterial growth and respiration rates. This phase 3 WLE model is a refinement of the proof-of-concept developed in phase 2, which was the first attempt to use NPP to simulate cyanobacteria in the TMDL model. The calibration of the calculated NPP WLE model was successful, with performance metrics indicating a good fit to calibration data, and the calculated NPP WLE model was able to simulate mid-season bloom decreases, a feature that previous models could not reproduce.In order to use the model to simulate future scenarios based on phosphorus load reduction, a multivariate regression model was created to simulate NPP as a function of the model state variables (phosphorus and chlorophyll a) and measured meteorological and temperature model inputs. The NPP time series was split into a low- and high-frequency component using wavelet analysis, and regression models were fit to the components separately, with moderate success.The regression models for NPP were incorporated in the WLE model, referred to as the “scenario” WLE (SWLE), and the fit statistics for phosphorus during the calibration period were mostly unchanged. The fit statistics for chlorophyll a, however, were degraded. These statistics are still an improvement over prior models, and indicate that the SWLE is appropriate for long-term predictions even though it misses some of the seasonal variations in chlorophyll a.The complete whole lake SWLE model, with multivariate regression to predict NPP, was used to make long-term simulations of the response to 10-, 20-, and 40-percent reductions in tributary nutrient loads. The long-term mean water column concentration of total phosphorus was reduced by 9, 18, and 36 percent, respectively, in response to these load reductions. The long-term water column chlorophyll a concentration was reduced by 4, 13, and 44 percent, respectively. The adjustment to a new equilibrium between the water column and sediments occurred over about 30 years.

Calibration of a biome-biogeochemical cycles model for modeling the net primary production of teak forests through inverse modeling of remotely sensed data

NASA Astrophysics Data System (ADS)

Imvitthaya, Chomchid; Honda, Kiyoshi; Lertlum, Surat; Tangtham, Nipon

2011-01-01

In this paper, we present the results of a net primary production (NPP) modeling of teak (Tectona grandis Lin F.), an important species in tropical deciduous forests. The biome-biogeochemical cycles or Biome-BGC model was calibrated to estimate net NPP through the inverse modeling approach. A genetic algorithm (GA) was linked with Biome-BGC to determine the optimal ecophysiological model parameters. The Biome-BGC was calibrated by adjusting the ecophysiological model parameters to fit the simulated LAI to the satellite LAI (SPOT-Vegetation), and the best fitness confirmed the high accuracy of generated ecophysioligical parameter from GA. The modeled NPP, using optimized parameters from GA as input data, was evaluated using daily NPP derived by the MODIS satellite and the annual field data in northern Thailand. The results showed that NPP obtained using the optimized ecophysiological parameters were more accurate than those obtained using default literature parameterization. This improvement occurred mainly because the model's optimized parameters reduced the bias by reducing systematic underestimation in the model. These Biome-BGC results can be effectively applied in teak forests in tropical areas. The study proposes a more effective method of using GA to determine ecophysiological parameters at the site level and represents a first step toward the analysis of the carbon budget of teak plantations at the regional scale.

The environmental constraint needs for design improvements to the Saligny I/LLW-repository near Cernavoda NPP

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barariu, Gheorghe

2007-07-01

The paper presents the new perspectives on the development of the L/ILW Final Repository Project which will be built near Cernavoda NPP. The Repository is designed to satisfy the main performance objectives in accordance to IAEA recommendation. Starting in October 1996, Romania became a country with an operating nuclear power plant. Reactor 2 reached the criticality on May 6, 2007 and it will be put in commercial operation in September 2007. The Ministry of Economy and Finance has decided to proceed with the commissioning of Units 3 and 4 of Cernavoda NPP till 2014. The Strategy for radioactive waste managementmore » was elaborated by National Agency for Radioactive Waste (ANDRAD), the jurisdictional authority for definitive disposal and the coordination of nuclear spent fuel and radioactive waste management (Order 844/2004) with attributions established by Governmental Decision (GO) 31/2006. The Strategy specifies the commissioning of the Saligny L/IL Radwaste Repository near Cernavoda NPP in 2014. When designing the L/IL Radwaste Repository, the following prerequisites have been taken into account: 1) Cernavoda NPP will be equipped with 4 Candu 6 units. 2) National Legislation in radwaste management will be reviewed and/or completed to harmonize with UE standards 3) The selected site is now in process of confirmation after a comprehensive set of interdisciplinary investigations. (author)« less

NPOESS Preparatory Project Validation Program for Ocean Data Products from VIIRS

NASA Astrophysics Data System (ADS)

Arnone, R.; Jackson, J. M.

2009-12-01

The National Polar-orbiting Operational Environmental Satellite Suite (NPOESS) Program, in partnership with National Aeronautical Space Administration (NASA), will launch the NPOESS Preparatory Project (NPP), a risk reduction and data continuity mission, prior to the first operational NPOESS launch. The NPOESS Program, in partnership with Northrop Grumman Aerospace Systems (NGAS), will execute the NPP Validation program to ensure the data products comply with the requirements of the sponsoring agencies. Data from the NPP Visible/Infrared Imager/Radiometer Suite (VIIRS) will be used to produce Environmental Data Records (EDR's) of Ocean Color/Chlorophyll and Sea Surface Temperature. The ocean Cal/Val program is designed to address an “end to end” capability from sensor to end product and is developed based on existing ongoing government satellite ocean remote sensing capabilities that are currently in use with NASA research and Navy and NOAA operational products. Therefore, the plan focuses on the extension of known reliable methods and capabilities currently used with the heritage sensors that will be extended to the NPP and NPOESS ocean product Cal/Val effort. This is not a fully “new” approach but it is designed to be the most reliable and cost effective approach to developing an automated Cal/Val system for VIIRS while retaining highly accurate procedures and protocols. This presentation will provide an overview of the approaches, data and schedule for the validation of the NPP VIIRS Ocean environmental data products.

The total release of xenon-133 from the Fukushima Dai-ichi nuclear power plant accident.

PubMed

Stohl, Andreas; Seibert, Petra; Wotawa, Gerhard

2012-10-01

The accident at the Fukushima Dai-ichi nuclear power plant (FD-NPP) on 11 March 2011 released large amounts of radioactivity into the atmosphere. We determine the total emission of the noble gas xenon-133 ((133)Xe) using global atmospheric concentration measurements. For estimating the emissions, we used three different methods: (i) using a purely observation-based multi-box model, (ii) comparisons of dispersion model results driven with GFS meteorological data with the observation data, and (iii) such comparisons with the dispersion model driven by ECMWF data. From these three methods, we have obtained total (133)Xe releases from FD-NPP of (i) 16.7 ± 1.9 EBq, (ii) 14.2 ± 0.8 EBq, and (iii) 19.0 ± 3.4 EBq, respectively. These values are substantially larger than the entire (133)Xe inventory of FD-NPP of about 12.2 EBq derived from calculations of nuclear fuel burn-up. Complete release of the entire (133)Xe inventory of FD-NPP and additional release of (133)Xe due to the decay of iodine-133 ((133)I), which can add another 2 EBq to the (133)Xe FD-NPP inventory, is required to explain the atmospheric observations. Two of our three methods indicate even higher emissions, but this may not be a robust finding given the differences between our estimates. Copyright © 2012 Elsevier Ltd. All rights reserved.

42 CFR 414.39 - Special rules for payment of care plan oversight.

Code of Federal Regulations, 2013 CFR

2013-10-01

... this section a nonphysician practitioner (NPP) is a nurse practitioner, clinical nurse specialist or physician assistant. (b) Exception. Separate payment is made under the following conditions for physician... the NPP is a nurse practitioner or clinical nurse specialist, the physician signing the plan of care...

42 CFR 414.39 - Special rules for payment of care plan oversight.

Code of Federal Regulations, 2012 CFR

2012-10-01

... this section a nonphysician practitioner (NPP) is a nurse practitioner, clinical nurse specialist or physician assistant. (b) Exception. Separate payment is made under the following conditions for physician... the NPP is a nurse practitioner or clinical nurse specialist, the physician signing the plan of care...

42 CFR 414.39 - Special rules for payment of care plan oversight.

Code of Federal Regulations, 2010 CFR

2010-10-01

... this section a nonphysician practitioner (NPP) is a nurse practitioner, clinical nurse specialist or physician assistant. (b) Exception. Separate payment is made under the following conditions for physician... the NPP is a nurse practitioner or clinical nurse specialist, the physician signing the plan of care...

42 CFR 414.39 - Special rules for payment of care plan oversight.

Code of Federal Regulations, 2011 CFR

2011-10-01

... this section a nonphysician practitioner (NPP) is a nurse practitioner, clinical nurse specialist or physician assistant. (b) Exception. Separate payment is made under the following conditions for physician... the NPP is a nurse practitioner or clinical nurse specialist, the physician signing the plan of care...

42 CFR 414.39 - Special rules for payment of care plan oversight.

Code of Federal Regulations, 2014 CFR

2014-10-01

... this section a nonphysician practitioner (NPP) is a nurse practitioner, clinical nurse specialist or physician assistant. (b) Exception. Separate payment is made under the following conditions for physician... the NPP is a nurse practitioner or clinical nurse specialist, the physician signing the plan of care...

Unique Chernobyl Cranes for Deconstruction Activities in the New Safe Confinement - 13542

DOE Office of Scientific and Technical Information (OSTI.GOV)

Parameswaran, N.A. Vijay; Chornyy, Igor; Owen, Rob

2013-07-01

The devastation left behind from the Chernobyl nuclear power plant (ChNPP) Unit 4 accident which occurred on April 26, 1986 presented unparalleled technical challenges to the world engineering and scientific community. One of the largest tasks that are in progress is the design and construction of the New Safe Confinement (NSC). The NSC is an engineered enclosure for the entire object shelter (OS) that includes a suite of process equipment. The process equipment will be used for the dismantling of the destroyed Chernobyl Nuclear Power Plant (ChNPP) Unit. One of the major mechanical handling systems to be installed in themore » NSC is the Main Cranes System (MCS). The planned decontamination and decommissioning or dismantling (D and D) activities will require the handling of heavily shielded waste disposal casks containing nuclear fuel as well as lifting and transporting extremely large structural elements. These activities, to be performed within the NSC, will require large and sophisticated cranes. The article will focus on the unique design features of the MCS for the D and D activities. (authors)« less

Human-In-The-Loop Simulation in Support of Long-Term Sustainability of Light Water Reactors

DOE PAGES

Hallbert, Bruce P

2015-01-01

Reliable instrumentation, information, and control systems technologies are essential to ensuring safe and efficient operation of the U.S. light water reactor (LWR) fleet. These technologies affect every aspect of nuclear power plant (NPP) and balance-of-plant operations. In 1997, the National Research Council conducted a study concerning the challenges involved in modernization of digital instrumentation and control systems in NPPs. Their findings identified the need for new II&C technology integration. The NPP owners and operators realize that this analog technology represents a significant challenge to sustaining the operation of the current fleet of NPPs. Beyond control systems, new technologies are neededmore » to monitor and characterize the effects of aging and degradation in critical areas of key structures, systems, and components. The objective of the efforts sponsored by the U.S. Department of Energy is to develop, demonstrate, and deploy new digital technologies for II&C architectures and provide monitoring capabilities to ensure the continued safe, reliable, and economic operation of the nation’s NPPs.« less

Enhancement and evaluation of an algorithm for atmospheric profiling continuity from Aqua to Suomi-NPP

NASA Astrophysics Data System (ADS)

Lipton, A.; Moncet, J. L.; Payne, V.; Lynch, R.; Polonsky, I. N.

2017-12-01

We will present recent results from an algorithm for producing climate-quality atmospheric profiling earth system data records (ESDRs) for application to data from hyperspectral sounding instruments, including the Atmospheric InfraRed Sounder (AIRS) on EOS Aqua and the Cross-track Infrared Sounder (CrIS) on Suomi-NPP, along with their companion microwave sounders, AMSU and ATMS, respectively. The ESDR algorithm uses an optimal estimation approach and the implementation has a flexible, modular software structure to support experimentation and collaboration. Data record continuity benefits from the fact that the same algorithm can be applied to different sensors, simply by providing suitable configuration and data files. Developments to be presented include the impact of a radiance-based pre-classification method for the atmospheric background. In addition to improving retrieval performance, pre-classification has the potential to reduce the sensitivity of the retrievals to the climatological data from which the background estimate and its error covariance are derived. We will also discuss evaluation of a method for mitigating the effect of clouds on the radiances, and enhancements of the radiative transfer forward model.

Growing Season Conditions Mediate the Dependence of Aspen on Redistributed Snow Under Climate Change.

NASA Astrophysics Data System (ADS)

Soderquist, B.; Kavanagh, K.; Link, T. E.; Seyfried, M. S.; Strand, E. K.

2016-12-01

Precipitation regimes in many semiarid ecosystems are becoming increasingly dominated by winter rainfall as a result of climate change. Across these regions, snowpack plays a vital role in the distribution and timing of soil moisture availability. Rising temperatures will result in a more uniform distribution of soil moisture, advanced spring phenology, and prolonged growing seasons. Productive and wide ranging tree species like aspen, Populus tremuloides, may experience increased vulnerability to drought and mortality resulting from both reduced snowpack and increased evaporative demand during the growing season. We simulated the net primary production (NPP) of aspen stands spanning the rain:snow transition zone in the Reynolds Creek Critical Zone Observatory (RCCZO) in southwest Idaho, USA. Within the RCCZO, the total amount of precipitation has remained unchanged over the past 50 years, however the percentage of the precipitation falling as snow has declined by approximately 4% per decade at mid-elevation sites. The biogeochemical process model Biome-BGC was used to simulate aspen NPP at three stands located directly below snowdrifts that provide melt water late into the spring. After adjusting precipitation inputs to account for the redistribution of snow, we assessed climate change impacts on future aspen productivity. Mid-century (2046-2065) aspen NPP was simulated using temperature projections from a multi-model average under high emission conditions using the Multivariate Adaptive Constructed Analogs (MACA) data set. While climate change simulations indicated over a 20% decrease in annual NPP for some years, NPP rates for other mid-century years remained relatively unchanged due to variations in growing season conditions. Mid-century years with the largest decreases in NPP typically showed increased spring transpiration rates resulting from earlier leaf flush combined with warmer spring conditions. During these years, the onset of drought stress occurred earlier due to increased early season soil moisture use and higher summer vapor pressure deficits. These results indicate that vegetation response to decreased snowpack can result in significant drought stress although phenological shifts that better align leaf production and precipitation ameliorate this response in some years. Precipitation regimes in many semiarid ecosystems are becoming increasingly dominated by winter rainfall as a result of climate change. Across these regions, snowpack plays a vital role in the distribution and timing of soil moisture availability. Rising temperatures will result in a more uniform distribution of soil moisture, advanced spring phenology, and prolonged growing seasons. Productive and wide ranging tree species like aspen, Populus tremuloides, may experience increased vulnerability to drought and mortality resulting from both reduced snowpack and increased evaporative demand during the growing season. We simulated the net primary production (NPP) of aspen stands spanning the rain:snow transition zone in the Reynolds Creek Critical Zone Observatory (RCCZO) in southwest Idaho, USA. Within the RCCZO, the total amount of precipitation has remained unchanged over the past 50 years, however the percentage of the precipitation falling as snow has declined by approximately 4% per decade at mid-elevation sites. The biogeochemical process model Biome-BGC was used to simulate aspen NPP at three stands located directly below snowdrifts that provide melt water late into the spring. After adjusting precipitation inputs to account for the redistribution of snow, we assessed climate change impacts on future aspen productivity. Mid-century (2046-2065) aspen NPP was simulated using temperature projections from a multi-model average under high emission conditions using the Multivariate Adaptive Constructed Analogs (MACA) data set. While climate change simulations indicated over a 20% decrease in annual NPP for some years, NPP rates for other mid-century years remained relatively unchanged due to variations in growing season conditions. Mid-century years with the largest decreases in NPP typically showed increased spring transpiration rates resulting from earlier leaf flush combined with warmer spring conditions. During these years, the onset of drought stress occurred earlier due to increased early season soil moisture use and higher summer vapor pressure deficits. These results indicate that vegetation response to decreased snowpack can result in significant drought stress although phenological shifts that better align leaf production and precipitation ameliorate this response in some years.

Incorporating grassland management in a global vegetation model

NASA Astrophysics Data System (ADS)

Chang, Jinfeng; Viovy, Nicolas; Vuichard, Nicolas; Ciais, Philippe; Wang, Tao; Cozic, Anne; Lardy, Romain; Graux, Anne-Isabelle; Klumpp, Katja; Martin, Raphael; Soussana, Jean-François

2013-04-01

Grassland is a widespread vegetation type, covering nearly one-fifth of the world's land surface (24 million km2), and playing a significant role in the global carbon (C) cycle. Most of grasslands in Europe are cultivated to feed animals, either directly by grazing or indirectly by grass harvest (cutting). A better understanding of the C fluxes from grassland ecosystems in response to climate and management requires not only field experiments but also the aid of simulation models. ORCHIDEE process-based ecosystem model designed for large-scale applications treats grasslands as being unmanaged, where C / water fluxes are only subject to atmospheric CO2 and climate changes. Our study describes how management of grasslands is included in the ORCHIDEE, and how management affects modeled grassland-atmosphere CO2 fluxes. The new model, ORCHIDEE-GM (Grassland Management) is capable with a management module inspired from a grassland model (PaSim, version 5.0), of accounting for two grassland management practices (cutting and grazing). The evaluation of the results of ORCHIDEE-GM compared with those of ORCHIDEE at 11 European sites equipped with eddy covariance and biometric measurements, show that ORCHIDEE-GM can capture realistically the cut-induced seasonal variation in biometric variables (LAI: Leaf Area Index; AGB: Aboveground Biomass) and in CO2 fluxes (GPP: Gross Primary Productivity; TER: Total Ecosystem Respiration; and NEE: Net Ecosystem Exchange). But improvements at grazing sites are only marginal in ORCHIDEE-GM, which relates to the difficulty in accounting for continuous grazing disturbance and its induced complex animal-vegetation interactions. Both NEE and GPP on monthly to annual timescales can be better simulated in ORCHIDEE-GM than in ORCHIDEE without management. At some sites, the model-observation misfit in ORCHIDEE-GM is found to be more related to ill-constrained parameter values than to model structure. Additionally, ORCHIDEE-GM is able to simulate forage yield, herbage consumption, animal products (e.g. milk), animal respiration and animal CH4 emissions. These new variables combined with organic C fertilizer applied on the field could provide a more complete view of grasslands C fluxes for applications of the model on a grid. The 11 site simulations of this study show that European grasslands generally are C sinks (positive NBP). At grazed grasslands, both C export in the form of milk production and CH4 emissions by animals only consist a minor part of net primary production (NPP), and this means that NBP mainly depends on NPP. On the contrary, the cut sites accumulate less C in soils because a large part of NPP has been exported as forage production. Furthermore, theoretically potential of productivity and livestock density in European grassland can be predicted by ORCHIDEE-GM, based on the strategy modeling of the optimal livestock density and management change.

Assessing the effects of management on forest growth across France: insights from a new functional-structural model.

PubMed

Guillemot, Joannès; Delpierre, Nicolas; Vallet, Patrick; François, Christophe; Martin-StPaul, Nicolas K; Soudani, Kamel; Nicolas, Manuel; Badeau, Vincent; Dufrêne, Eric

2014-09-01

The structure of a forest stand, i.e. the distribution of tree size features, has strong effects on its functioning. The management of the structure is therefore an important tool in mitigating the impact of predicted changes in climate on forests, especially with respect to drought. Here, a new functional-structural model is presented and is used to assess the effects of management on forest functioning at a national scale. The stand process-based model (PBM) CASTANEA was coupled to a stand structure module (SSM) based on empirical tree-to-tree competition rules. The calibration of the SSM was based on a thorough analysis of intersite and interannual variability of competition asymmetry. The coupled CASTANEA-SSM model was evaluated across France using forest inventory data, and used to compare the effect of contrasted silvicultural practices on simulated stand carbon fluxes and growth. The asymmetry of competition varied consistently with stand productivity at both spatial and temporal scales. The modelling of the competition rules enabled efficient prediction of changes in stand structure within the CASTANEA PBM. The coupled model predicted an increase in net primary productivity (NPP) with management intensity, resulting in higher growth. This positive effect of management was found to vary at a national scale across France: the highest increases in NPP were attained in forests facing moderate to high water stress; however, the absolute effect of management on simulated stand growth remained moderate to low because stand thinning involved changes in carbon allocation at the tree scale. This modelling approach helps to identify the areas where management efforts should be concentrated in order to mitigate near-future drought impact on national forest productivity. Around a quarter of the French temperate oak and beech forests are currently in zones of high vulnerability, where management could thus mitigate the influence of climate change on forest yield.

The NPOESS Preparatory Project Science Data Segment (SDS) Data Depository and Distribution Element (SD3E) System Architecture

NASA Technical Reports Server (NTRS)

Ho, Evelyn L.; Schweiss, Robert J.

2008-01-01

The National Polar-orbiting Operational Environmental Satellite System (NPOESS) Preparatory Project (NPP) Science Data Segment (SDS) will make daily data requests for approximately six terabytes of NPP science products for each of its six environmental assessment elements from the operational data providers. As a result, issues associated with duplicate data requests, data transfers of large volumes of diverse products, and data transfer failures raised concerns with respect to the network traffic and bandwidth consumption. The NPP SDS Data Depository and Distribution Element (SD3E) was developed to provide a mechanism for efficient data exchange, alleviate duplicate network traffic, and reduce operational costs.

Developing and applying modern methods of leakage monitoring and state estimation of fuel at the Novovoronezh nuclear power plant

NASA Astrophysics Data System (ADS)

Povarov, V. P.; Tereshchenko, A. B.; Kravchenko, Yu. N.; Pozychanyuk, I. V.; Gorobtsov, L. I.; Golubev, E. I.; Bykov, V. I.; Likhanskii, V. V.; Evdokimov, I. A.; Zborovskii, V. G.; Sorokin, A. A.; Kanyukova, V. D.; Aliev, T. N.

2014-02-01

The results of developing and implementing the modernized fuel leakage monitoring methods at the shut-down and running reactor of the Novovoronezh nuclear power plant (NPP) are presented. An automated computerized expert system integrated with an in-core monitoring system (ICMS) and installed at the Novovoronezh NPP unit no. 5 is described. If leaky fuel elements appear in the core, the system allows one to perform on-line assessment of the parameters of leaky fuel assemblies (FAs). The computer expert system units designed for optimizing the operating regimes and enhancing the fuel usage efficiency at the Novovoronezh NPP unit no. 5 are now being developed.

Evaluation of MODIS NPP and GPP products across multiple biomes.

Treesearch

David P. Turner; William D. Ritts; Warren B. Cohen; Stith T. Gower; Steve W. Running; Maosheng Zhao; Marcos H. Costa; Al A. Kirschbaum; Jay M. Ham; Scott R. Saleska; Douglas E. Ahl

2006-01-01

Estimates of daily gross primary production (GPP) and annual net primary production (NPP) at the 1 km spatial resolution are now produced operationally for the global terrestrial surface using imagery from the MODIS (Moderate Resolution Imaging Spectroradiometer) sensor. Ecosystem-level measurements of GPP at eddy covariance flux towers and plot-level measurements of...

Global Potential Net Prmary Production Predicted from Vegetation Class, Precipitation, and Temperature

USDA-ARS?s Scientific Manuscript database

Net Primary Production (NPP), the difference between CO2 fixed by photosynthesis and CO2 lost to autotrophic respiration, is one of the most important components of the carbon cycle. Our goal was to develop a simple regression model to estimate global NPP using climate and land cover data. Approxima...

Great Lakes in January

NASA Image and Video Library

2017-12-08

This image taken on January 13, 2015 from the Suomi NPP satellite's VIIRS instrument shows the Great Lakes and surrounding areas. The latest Great Lakes Surface Environmental Analysis (GLSEA) from the NOAA Great Lakes Environmental Research Laboratory shows total ice cover of 29.3% as of January 13th. Credit: NOAA/NASA/NPP Via NOAA Environmental Visualization Laboratory

Selective Induction of Tumor Cell Apoptosis by a Novel P450-mediated Reactive Oxygen Species (ROS) Inducer Methyl 3-(4-Nitrophenyl) Propiolate*

PubMed Central

Sun, Xiaoxiao; Ai, Midan; Wang, Ying; Shen, Shensi; Gu, Yuan; Jin, Yi; Zhou, Zuyu; Long, Yaqiu; Yu, Qiang

2013-01-01

Induction of tumor cell apoptosis has been recognized as a valid anticancer strategy. However, therapeutic selectivity between tumor and normal cells has always been a challenge. Here, we report a novel anti-cancer compound methyl 3-(4-nitrophenyl) propiolate (NPP) preferentially induces apoptosis in tumor cells through P450-catalyzed reactive oxygen species (ROS) production. A compound sensitivity study on multiple cell lines shows that tumor cells with high basal ROS levels, low antioxidant capacities, and p53 mutations are especially sensitive to NPP. Knockdown of p53 sensitized non-transformed cells to NPP-induced cell death. Additionally, by comparing NPP with other ROS inducers, we show that the susceptibility of tumor cells to the ROS-induced cell death is influenced by the mode, amount, duration, and perhaps location of ROS production. Our studies not only discovered a unique anticancer drug candidate but also shed new light on the understanding of ROS generation and function and the potential application of a ROS-promoting strategy in cancer treatment. PMID:23382387

The Plasmodium falciparum rhoptry protein RhopH3 plays essential roles in host cell invasion and nutrient uptake

PubMed Central

Sherling, Emma S; Knuepfer, Ellen; Brzostowski, Joseph A; Miller, Louis H; Blackman, Michael J; van Ooij, Christiaan

2017-01-01

Merozoites of the protozoan parasite responsible for the most virulent form of malaria, Plasmodium falciparum, invade erythrocytes. Invasion involves discharge of rhoptries, specialized secretory organelles. Once intracellular, parasites induce increased nutrient uptake by generating new permeability pathways (NPP) including a Plasmodium surface anion channel (PSAC). RhopH1/Clag3, one member of the three-protein RhopH complex, is important for PSAC/NPP activity. However, the roles of the other members of the RhopH complex in PSAC/NPP establishment are unknown and it is unclear whether any of the RhopH proteins play a role in invasion. Here we demonstrate that RhopH3, the smallest component of the complex, is essential for parasite survival. Conditional truncation of RhopH3 substantially reduces invasive capacity. Those mutant parasites that do invade are defective in nutrient import and die. Our results identify a dual role for RhopH3 that links erythrocyte invasion to formation of the PSAC/NPP essential for parasite survival within host erythrocytes. DOI: http://dx.doi.org/10.7554/eLife.23239.001 PMID:28252384

Spatiotemporal changes in vegetation net primary productivity in the arid region of Northwest China, 2001 to 2012

NASA Astrophysics Data System (ADS)

Li, Zhen; Pan, Jinghu

2018-03-01

Net primary productivity (NPP) is recognized as an important index of ecosystem conditions and a key variable of the terrestrial carbon cycle. It also represents the comprehensive effects of climate change and anthropogenic activity on terrestrial vegetation. In this study, the temporal-spatial pattern of NPP for the period 2001-2012 was analyzed using a remote sensing-based carbon model (i.e., the Carnegie-Ames-Stanford Approach, CASA) in addition to other methods, such as linear trend analysis, standard deviation, and the Hurst index. Temporally, NPP showed a significant increasing trend for the arid region of Northwest China (ARNC), with an annual increase of 2.327 g C. Maximum and minimum productivity values appeared in July and December, respectively. Spatially, the NPP was relatively stable in the temperate and warm-temperate desert regions of Northwest China, while temporally, it showed an increasing trend. However, some attention should be given to the northwestern warm-temperate desert region, where there is severe continuous degradation and only a slight improvement trend.

The theoretical limit to plant productivity.

PubMed

DeLucia, Evan H; Gomez-Casanovas, Nuria; Greenberg, Jonathan A; Hudiburg, Tara W; Kantola, Ilsa B; Long, Stephen P; Miller, Adam D; Ort, Donald R; Parton, William J

2014-08-19

Human population and economic growth are accelerating the demand for plant biomass to provide food, fuel, and fiber. The annual increment of biomass to meet these needs is quantified as net primary production (NPP). Here we show that an underlying assumption in some current models may lead to underestimates of the potential production from managed landscapes, particularly of bioenergy crops that have low nitrogen requirements. Using a simple light-use efficiency model and the theoretical maximum efficiency with which plant canopies convert solar radiation to biomass, we provide an upper-envelope NPP unconstrained by resource limitations. This theoretical maximum NPP approached 200 tC ha(-1) yr(-1) at point locations, roughly 2 orders of magnitude higher than most current managed or natural ecosystems. Recalculating the upper envelope estimate of NPP limited by available water reduced it by half or more in 91% of the land area globally. While the high conversion efficiencies observed in some extant plants indicate great potential to increase crop yields without changes to the basic mechanism of photosynthesis, particularly for crops with low nitrogen requirements, realizing such high yields will require improvements in water use efficiency.

Shrubland primary production and soil respiration diverge along European climate gradient

PubMed Central

Reinsch, Sabine; Koller, Eva; Sowerby, Alwyn; de Dato, Giovanbattista; Estiarte, Marc; Guidolotti, Gabriele; Kovács-Láng, Edit; Kröel-Dulay, György; Lellei-Kovács, Eszter; Larsen, Klaus S.; Liberati, Dario; Peñuelas, Josep; Ransijn, Johannes; Robinson, David A.; Schmidt, Inger K.; Smith, Andrew R.; Tietema, Albert; Dukes, Jeffrey S.; Beier, Claus; Emmett, Bridget A.

2017-01-01

Above- and belowground carbon (C) stores of terrestrial ecosystems are vulnerable to environmental change. Ecosystem C balances in response to environmental changes have been quantified at individual sites, but the magnitudes and directions of these responses along environmental gradients remain uncertain. Here we show the responses of ecosystem C to 8–12 years of experimental drought and night-time warming across an aridity gradient spanning seven European shrublands using indices of C assimilation (aboveground net primary production: aNPP) and soil C efflux (soil respiration: Rs). The changes of aNPP and Rs in response to drought indicated that wet systems had an overall risk of increased loss of C but drier systems did not. Warming had no consistent effect on aNPP across the climate gradient, but suppressed Rs more at the drier sites. Our findings suggest that above- and belowground C fluxes can decouple, and provide no evidence of acclimation to environmental change at a decadal timescale. aNPP and Rs especially differed in their sensitivity to drought and warming, with belowground processes being more sensitive to environmental change. PMID:28256623

Spatial scaling of net primary productivity using subpixel landcover information

NASA Astrophysics Data System (ADS)

Chen, X. F.; Chen, Jing M.; Ju, Wei M.; Ren, L. L.

2008-10-01

Gridding the land surface into coarse homogeneous pixels may cause important biases on ecosystem model estimations of carbon budget components at local, regional and global scales. These biases result from overlooking subpixel variability of land surface characteristics. Vegetation heterogeneity is an important factor introducing biases in regional ecological modeling, especially when the modeling is made on large grids. This study suggests a simple algorithm that uses subpixel information on the spatial variability of land cover type to correct net primary productivity (NPP) estimates, made at coarse spatial resolutions where the land surface is considered as homogeneous within each pixel. The algorithm operates in such a way that NPP obtained from calculations made at coarse spatial resolutions are multiplied by simple functions that attempt to reproduce the effects of subpixel variability of land cover type on NPP. Its application to a carbon-hydrology coupled model(BEPS-TerrainLab model) estimates made at a 1-km resolution over a watershed (named Baohe River Basin) located in the southwestern part of Qinling Mountains, Shaanxi Province, China, improved estimates of average NPP as well as its spatial variability.

NPOESS Preparatory Project Validation Program for the Cross-track Infrared Sounder

NASA Astrophysics Data System (ADS)

Barnet, C.; Gu, D.; Nalli, N. R.

2009-12-01

The National Polar-orbiting Operational Environmental Satellite System (NPOESS) Program, in partnership with National Aeronautical Space Administration (NASA), will launch the NPOESS Preparatory Project (NPP), a risk reduction and data continuity mission, prior to the first operational NPOESS launch. The NPOESS Program, in partnership with Northrop Grumman Aerospace Systems, will execute the NPP Calibration and Validation (Cal/Val) program to ensure the data products comply with the requirements of the sponsoring agencies. The Cross-track Infrared Sounder (CrIS) and the Advanced Technology Microwave Sounder (ATMS) are two of the instruments that make up the suite of sensors on NPP. Together, CrIS and ATMS will produce three Environmental Data Records (EDRs) including the Atmospheric Vertical Temperature Profile (AVTP), Atmospheric Vertical Moisture Profile (AVMP), and the Atmospheric Vertical Pressure Profile (AVPP). The AVTP and the AVMP are both NPOESS Key Performance Parameters (KPPs). The validation plans establish science and user community leadership and participation, and demonstrated, cost-effective Cal/Val approaches. This presentation will provide an overview of the collaborative data, techniques, and schedule for the validation of the NPP CrIS and ATMS environmental data products.

Shrubland primary production and soil respiration diverge along European climate gradient

NASA Astrophysics Data System (ADS)

Reinsch, Sabine; Koller, Eva; Sowerby, Alwyn; de Dato, Giovanbattista; Estiarte, Marc; Guidolotti, Gabriele; Kovács-Láng, Edit; Kröel-Dulay, György; Lellei-Kovács, Eszter; Larsen, Klaus S.; Liberati, Dario; Peñuelas, Josep; Ransijn, Johannes; Robinson, David A.; Schmidt, Inger K.; Smith, Andrew R.; Tietema, Albert; Dukes, Jeffrey S.; Beier, Claus; Emmett, Bridget A.

2017-03-01

Above- and belowground carbon (C) stores of terrestrial ecosystems are vulnerable to environmental change. Ecosystem C balances in response to environmental changes have been quantified at individual sites, but the magnitudes and directions of these responses along environmental gradients remain uncertain. Here we show the responses of ecosystem C to 8-12 years of experimental drought and night-time warming across an aridity gradient spanning seven European shrublands using indices of C assimilation (aboveground net primary production: aNPP) and soil C efflux (soil respiration: Rs). The changes of aNPP and Rs in response to drought indicated that wet systems had an overall risk of increased loss of C but drier systems did not. Warming had no consistent effect on aNPP across the climate gradient, but suppressed Rs more at the drier sites. Our findings suggest that above- and belowground C fluxes can decouple, and provide no evidence of acclimation to environmental change at a decadal timescale. aNPP and Rs especially differed in their sensitivity to drought and warming, with belowground processes being more sensitive to environmental change.

Diagnosing phosphorus limitations in natural terrestrial ecosystems in carbon cycle models

NASA Astrophysics Data System (ADS)

Sun, Yan; Peng, Shushi; Goll, Daniel S.; Ciais, Philippe; Guenet, Bertrand; Guimberteau, Matthieu; Hinsinger, Philippe; Janssens, Ivan A.; Peñuelas, Josep; Piao, Shilong; Poulter, Benjamin; Violette, Aurélie; Yang, Xiaojuan; Yin, Yi; Zeng, Hui

2017-07-01

Most of the Earth System Models (ESMs) project increases in net primary productivity (NPP) and terrestrial carbon (C) storage during the 21st century. Despite empirical evidence that limited availability of phosphorus (P) may limit the response of NPP to increasing atmospheric CO2, none of the ESMs used in the previous Intergovernmental Panel on Climate Change assessment accounted for P limitation. We diagnosed from ESM simulations the amount of P need to support increases in carbon uptake by natural ecosystems using two approaches: the demand derived from (1) changes in C stocks and (2) changes in NPP. The C stock-based additional P demand was estimated to range between -31 and 193 Tg P and between -89 and 262 Tg P for Representative Concentration Pathway (RCP) 2.6 and RCP8.5, respectively, with negative values indicating a P surplus. The NPP-based demand, which takes ecosystem P recycling into account, results in a significantly higher P demand of 648-1606 Tg P for RCP2.6 and 924-2110 Tg P for RCP8.5. We found that the P demand is sensitive to the turnover of P in decomposing plant material, explaining the large differences between the NPP-based demand and C stock-based demand. The discrepancy between diagnosed P demand and actual P availability (potential P deficit) depends mainly on the assumptions about availability of the different soil P forms. Overall, future P limitation strongly depends on both soil P availability and P recycling on ecosystem scale.

Software to Compare NPP HDF5 Data Files

NASA Technical Reports Server (NTRS)

Wiegand, Chiu P.; LeMoigne-Stewart, Jacqueline; Ruley, LaMont T.

2013-01-01

This software was developed for the NPOESS (National Polar-orbiting Operational Environmental Satellite System) Preparatory Project (NPP) Science Data Segment. The purpose of this software is to compare HDF5 (Hierarchical Data Format) files specific to NPP and report whether the HDF5 files are identical. If the HDF5 files are different, users have the option of printing out the list of differences in the HDF5 data files. The user provides paths to two directories containing a list of HDF5 files to compare. The tool would select matching HDF5 file names from the two directories and run the comparison on each file. The user can also select from three levels of detail. Level 0 is the basic level, which simply states whether the files match or not. Level 1 is the intermediate level, which lists the differences between the files. Level 2 lists all the details regarding the comparison, such as which objects were compared, and how and where they are different. The HDF5 tool is written specifically for the NPP project. As such, it ignores certain attributes (such as creation_date, creation_ time, etc.) in the HDF5 files. This is because even though two HDF5 files could represent exactly the same granule, if they are created at different times, the creation date and time would be different. This tool is smart enough to ignore differences that are not relevant to NPP users.

Diagnosing phosphorus limitations in natural terrestrial ecosystems in carbon cycle models.

PubMed

Sun, Yan; Peng, Shushi; Goll, Daniel S; Ciais, Philippe; Guenet, Bertrand; Guimberteau, Matthieu; Hinsinger, Philippe; Janssens, Ivan A; Peñuelas, Josep; Piao, Shilong; Poulter, Benjamin; Violette, Aurélie; Yang, Xiaojuan; Yin, Yi; Zeng, Hui

2017-07-01

Most of the Earth System Models (ESMs) project increases in net primary productivity (NPP) and terrestrial carbon (C) storage during the 21st century. Despite empirical evidence that limited availability of phosphorus (P) may limit the response of NPP to increasing atmospheric CO 2 , none of the ESMs used in the previous Intergovernmental Panel on Climate Change assessment accounted for P limitation. We diagnosed from ESM simulations the amount of P need to support increases in carbon uptake by natural ecosystems using two approaches: the demand derived from (1) changes in C stocks and (2) changes in NPP. The C stock-based additional P demand was estimated to range between -31 and 193 Tg P and between -89 and 262 Tg P for Representative Concentration Pathway (RCP) 2.6 and RCP8.5, respectively, with negative values indicating a P surplus. The NPP-based demand, which takes ecosystem P recycling into account, results in a significantly higher P demand of 648-1606 Tg P for RCP2.6 and 924-2110 Tg P for RCP8.5. We found that the P demand is sensitive to the turnover of P in decomposing plant material, explaining the large differences between the NPP-based demand and C stock-based demand. The discrepancy between diagnosed P demand and actual P availability (potential P deficit) depends mainly on the assumptions about availability of the different soil P forms. Overall, future P limitation strongly depends on both soil P availability and P recycling on ecosystem scale.

Steeper declines in forest photosynthesis than respiration explain age-driven decreases in forest growth.

PubMed

Tang, Jianwu; Luyssaert, Sebastiaan; Richardson, Andrew D; Kutsch, Werner; Janssens, Ivan A

2014-06-17

The traditional view of forest dynamics originated by Kira and Shidei [Kira T, Shidei T (1967) Jap J Ecol 17:70-87] and Odum [Odum EP (1969) Science 164(3877):262-270] suggests a decline in net primary productivity (NPP) in aging forests due to stabilized gross primary productivity (GPP) and continuously increased autotrophic respiration (Ra). The validity of these trends in GPP and Ra is, however, very difficult to test because of the lack of long-term ecosystem-scale field observations of both GPP and Ra. Ryan and colleagues [Ryan MG, Binkley D, Fownes JH (1997) Ad Ecol Res 27:213-262] have proposed an alternative hypothesis drawn from site-specific results that aboveground respiration and belowground allocation decreased in aging forests. Here, we analyzed data from a recently assembled global database of carbon fluxes and show that the classical view of the mechanisms underlying the age-driven decline in forest NPP is incorrect and thus support Ryan's alternative hypothesis. Our results substantiate the age-driven decline in NPP, but in contrast to the traditional view, both GPP and Ra decline in aging boreal and temperate forests. We find that the decline in NPP in aging forests is primarily driven by GPP, which decreases more rapidly with increasing age than Ra does, but the ratio of NPP/GPP remains approximately constant within a biome. Our analytical models describing forest succession suggest that dynamic forest ecosystem models that follow the traditional paradigm need to be revisited.

Effects of ice storm on forest ecosystem of southern China in 2008 Shaoqiang Wang1, Lei Zhou1, Weimin Ju2, Kun Huang1 1Key Lab of Ecosystem Network Observation and Modeling, Institute of Geographical Sciences and Natural Resources Research, Beijing, 10010

NASA Astrophysics Data System (ADS)

Wang, Shaoqiang

2014-05-01

Evidence is mounting that an increase in extreme climate events has begun to occur worldwide during the recent decades, which affect biosphere function and biodiversity. Ecosystems returned to its original structures and functions to maintain its sustainability, which was closely dependent on ecosystem resilience. Understanding the resilience and recovery capacity of ecosystem to extreme climate events is essential to predicting future ecosystem responses to climate change. Given the overwhelming importance of this region in the overall carbon cycle of forest ecosystems in China, south China suffered a destructive ice storm in 2008. In this study, we used the number of freezing day and a process-based model (Boreal Ecosystem Productivity Simulator, BEPS) to characterize the spatial distribution of ice storm region in southeastern China and explore the impacts on carbon cycle of forest ecosystem over the past decade. The ecosystem variables, i.e. Net primary productivity (NPP), Evapotranspiration (ET), and Water use efficiency (WUE, the ratio of NPP to ET) from the outputs of BEPS models were used to detect the resistance and resilience of forest ecosystem in southern China. The pattern of ice storm-induced forest productivity widespread decline was closely related to the number of freezing day during the ice storm period. The NPP of forest area suffered heavy ice storm returned to normal status after five months with high temperature and ample moisture, indicated a high resilience of subtropical forest in China. The long-term changes of forest WUE remain stable, behaving an inherent sensitivity of ecosystem to extreme climate events. In addition, ground visits suggested that the recovery of forest productivity was attributed to rapid growth of understory. Understanding the variability and recovery threshold of ecosystem following extreme climate events help us to better simulate and predict the variability of ecosystem structure and function under current and future climate change.

Weather Satellite Enterprise Information Chain

NASA Astrophysics Data System (ADS)

Jamilkowski, M. L.; Grant, K. D.; Miller, S. W.; Cochran, S.

2015-12-01

NOAA & NASA are acquiring the next-generation civilian operational weather satellite: Joint Polar Satellite System (JPSS). Contributing the afternoon orbit & ground system (GS) to replace current NOAA POES Satellites, its sensors will collect meteorological, oceanographic & climatological data. The JPSS Common Ground System (CGS), consisting of C3 and IDP segments, is developed by Raytheon. It now flies the Suomi National Polar-orbiting Partnership (S-NPP) satellite, transferring data between ground facilities, processing them into environmental products for NOAA weather centers, and expanding to support JPSS-1 in 2017. As a multi-mission system, CGS provides combinations of C3, data processing, and product delivery for numerous NASA, NOAA, DoD and international missions.The CGS provides a wide range of support to a number of missions: Command and control and mission management for the S-NPP mission today, expanding this support to the JPSS-1 satellite mission in 2017 Data acquisition for S-NPP, the JAXA's Global Change Observation Mission - Water (GCOM-W1), POES, and the Defense Meteorological Satellite Program (DMSP) and Coriolis/WindSat for the DoD Data routing over a global fiber network for S-NPP, JPSS-1, GCOM-W1, POES, DMSP, Coriolis/WindSat, NASA EOS missions, MetOp for EUMETSAT and the National Science Foundation Environmental data processing and distribution for S-NPP, GCOM-W1 and JPSS-1 The CGS plays a key role in facilitating the movement and value-added enhancement of data all the way from satellite-based sensor data to delivery to the consumers who generate forecasts and produce watches and warnings. This presentation will discuss the information flow from sensors, through data routing and processing, and finally to product delivery. It will highlight how advances in architecture developed through lessons learned from S-NPP and implemented for JPSS-1 will increase data availability and reduce latency for end user applications.

Regional assessment of boreal forest productivity using an ecological process model and remote sensing parameter maps.

PubMed

Kimball, J. S.; Keyser, A. R.; Running, S. W.; Saatchi, S. S.

2000-06-01

An ecological process model (BIOME-BGC) was used to assess boreal forest regional net primary production (NPP) and response to short-term, year-to-year weather fluctuations based on spatially explicit, land cover and biomass maps derived by radar remote sensing, as well as soil, terrain and daily weather information. Simulations were conducted at a 30-m spatial resolution, over a 1205 km(2) portion of the BOREAS Southern Study Area of central Saskatchewan, Canada, over a 3-year period (1994-1996). Simulations of NPP for the study region were spatially and temporally complex, averaging 2.2 (+/- 0.6), 1.8 (+/- 0.5) and 1.7 (+/- 0.5) Mg C ha(-1) year(-1) for 1994, 1995 and 1996, respectively. Spatial variability of NPP was strongly controlled by the amount of aboveground biomass, particularly photosynthetic leaf area, whereas biophysical differences between broadleaf deciduous and evergreen coniferous vegetation were of secondary importance. Simulations of NPP were strongly sensitive to year-to-year variations in seasonal weather patterns, which influenced the timing of spring thaw and deciduous bud-burst. Reductions in annual NPP of approximately 17 and 22% for 1995 and 1996, respectively, were attributed to 3- and 5-week delays in spring thaw relative to 1994. Boreal forest stands with greater proportions of deciduous vegetation were more sensitive to the timing of spring thaw than evergreen coniferous stands. Similar relationships were found by comparing simulated snow depth records with 10-year records of aboveground NPP measurements obtained from biomass harvest plots within the BOREAS region. These results highlight the importance of sub-grid scale land cover complexity in controlling boreal forest regional productivity, the dynamic response of the biome to short-term interannual climate variations, and the potential implications of climate change and other large-scale disturbances.

Drought impact on forest carbon dynamics and fluxes in Amazonia.

PubMed

Doughty, Christopher E; Metcalfe, D B; Girardin, C A J; Amézquita, F Farfán; Cabrera, D Galiano; Huasco, W Huaraca; Silva-Espejo, J E; Araujo-Murakami, A; da Costa, M C; Rocha, W; Feldpausch, T R; Mendoza, A L M; da Costa, A C L; Meir, P; Phillips, O L; Malhi, Y

2015-03-05

In 2005 and 2010 the Amazon basin experienced two strong droughts, driven by shifts in the tropical hydrological regime possibly associated with global climate change, as predicted by some global models. Tree mortality increased after the 2005 drought, and regional atmospheric inversion modelling showed basin-wide decreases in CO2 uptake in 2010 compared with 2011 (ref. 5). But the response of tropical forest carbon cycling to these droughts is not fully understood and there has been no detailed multi-site investigation in situ. Here we use several years of data from a network of thirteen 1-ha forest plots spread throughout South America, where each component of net primary production (NPP), autotrophic respiration and heterotrophic respiration is measured separately, to develop a better mechanistic understanding of the impact of the 2010 drought on the Amazon forest. We find that total NPP remained constant throughout the drought. However, towards the end of the drought, autotrophic respiration, especially in roots and stems, declined significantly compared with measurements in 2009 made in the absence of drought, with extended decreases in autotrophic respiration in the three driest plots. In the year after the drought, total NPP remained constant but the allocation of carbon shifted towards canopy NPP and away from fine-root NPP. Both leaf-level and plot-level measurements indicate that severe drought suppresses photosynthesis. Scaling these measurements to the entire Amazon basin with rainfall data, we estimate that drought suppressed Amazon-wide photosynthesis in 2010 by 0.38 petagrams of carbon (0.23-0.53 petagrams of carbon). Overall, we find that during this drought, instead of reducing total NPP, trees prioritized growth by reducing autotrophic respiration that was unrelated to growth. This suggests that trees decrease investment in tissue maintenance and defence, in line with eco-evolutionary theories that trees are competitively disadvantaged in the absence of growth. We propose that weakened maintenance and defence investment may, in turn, cause the increase in post-drought tree mortality observed at our plots.

[Effects of selective cutting on the carbon density and net primary productivity of a mixed broadleaved-Korean pine forest in Northeast China].

PubMed

Liu, Qi; Cai, Hui-Ying; Jin, Guang-Ze

2013-10-01

To accurately quantify forest carbon density and net primary productivity (NPP) is of great significance in estimating the role of forest ecosystems in global carbon cycle. By using the forest inventory and allometry approaches, this paper measured the carbon density and NPP of the virgin broadleaved-Korean pine (Pinus koraiensis) forest and of the broadleaved-Korean pine forest after 34 years selective-cutting (the cutting intensity was 30%, and the cutting trees were in large diameter class). The total carbon density of the virgin and selective-cutting broadleaved-Korean pine forests was (397.95 +/- 93.82) and (355.61 +/- 59.37) t C x hm(-2), respectively. In the virgin forest, the carbon density of the vegetation, debris, and soil accounted for 31.0%, 3.1%, and 65.9% of the total carbon pool, respectively; in the selective-cutting forest, the corresponding values were 31.7%, 2.9%, and 65.4%, respectively. No significant differences were observed in the total carbon density and the carbon density of each component between the two forests. The total NPP of the virgin and selective-cutting forests was (36.27 +/- 0.36) and (6.35 +/- 0.70) t C x hm(-2) x a(-1), among which, the NPP of overstory, understory, and fine roots in virgin forest and selective-cutting forest accounted for 60.3%, 2.0%, and 37.7%, and 66.1%, 2.0%, and 31.2%, respectively. No significant differences were observed in the total NPP and the contribution rate of each component between the two forests. However, the ratios of the needle and broadleaf NPPs of the virgin and selective-cutting forests were 47.24:52.76 and 20.48:79.52, respectively, with a significant difference. The results indicated that the carbon density and NPP of the broadleaved-Korean pine forest after 34 years selective-cutting recovered to the levels of the virgin broadleaved-Korean pine forest.

Effect of Dietary Nutrient Density on Small Intestinal Phosphate Transport and Bone Mineralization of Broilers during the Growing Period.

PubMed

Li, Jianhui; Yuan, Jianmin; Miao, Zhiqiang; Song, Zhigang; Yang, Yu; Tian, Wenxia; Guo, Yuming

2016-01-01

A 2 × 4 factorial experiment was conducted to determine the effects of dietary nutrient density on growth performance, small intestinal epithelial phosphate transporter expression, and bone mineralization of broiler chicks fed with diets with different nutrient densities and nonphytate phosphorus (NPP) levels. The broilers were fed with the same starter diets from 0 to 21 days of age. In the grower phase (day 22 to 42), the broilers were randomly divided into eight groups according to body weight. Relatively high dietary nutrient density (HDND) and low dietary nutrient density (LDND) diets were assigned metabolic energy (ME) values of 3,150 and 2,950 kcal/kg, respectively. Crude protein and essential amino acid levels were maintained in the same proportion as ME to prepare the two diet types. NPP levels were 0.25%, 0.30%, 0.35%, and 0.40% of the diets. Results showed that a HDND diet significantly increased the body weight gain (BWG) of broilers and significantly decreased the feed conversion ratio and NPP consumed per BWG. HDND significantly decreased tibial P content of the broilers. Conversely, mRNA expression of NaPi-IIb and protein expression of calbindin were significantly increased in the intestine of broilers fed a HDND diet. HDND also increased vitamin D receptor (VDR) expression, especially at a relatively low dietary NPP level (0.25%). The mRNA expression of NaPi-IIa in the kidneys was significantly increased at a relatively low dietary NPP level (0.25%) to maintain P balance. Tibial P, calcium, and ash content were significantly decreased, as were calbindin and VDR expression levels in the intestine at a low NPP level. Therefore, HDND improved the growth rate of broilers and increased the expression of phosphate and calcium transporter in the small intestine, but adversely affected bone mineralization.

Throughfall reduction and nutrient availability effects on carbon balance in loblolly pine plantations in the southeastern United States

NASA Astrophysics Data System (ADS)

Bracho, R. G.; Vogel, J.; Jokela, E. J.; Cucinella, J.; Noormets, A.; Laviner, M. A.; Gonzalez-Benecke, C. A.; Samuelson, L. J.; Markewitz, D.; Will, R.; Meek, C.; Seiler, J.; Strahm, B. D.; McElligott, K.; Martin, T.

2016-12-01

Planted loblolly pine covers over 11 million hectares in the southeastern United States. Occurring across a range of climatic conditions, these pine plantations are critical for the regional economy and offset a significant fraction of anthropogenic CO2 emissions. Loblolly pine productivity has been enhanced through genetic improvement and intensive silviculture. However, climate projections forecast higher air temperature and more variable precipitation patterns for the region. A critical question is how silvicultural practices will interact with projected climate change to affect loblolly pine carbon balance. A fertilization by throughfall reduction experiment was established in the spring of 2012 at four loblolly pine plantations at the margins of the natural range of the specie (Florida FL, Georgia GA, Oklahoma OK and Virginia VA). Net primary productivity (NPP) was estimated from repeated tree inventories and net ecosystem productivity (NEP) as the difference between NPP and heterotrophic respiration (RH). Soil respiration (RS) and RH were measured simultaneously several times during the experiment. Throughfall reduction significantly decreased surface soil water content at all sites. After four years of treatment, fertilization increased NPP at all sites and throughfall reduction had a negative effect on NPP at the GA and OK sites. The combination fertilization x throughfall reduction did not have a significant effect on NPP. RS and RH were, in general negatively affected by fertilization and throughfall reduction with differential responses between sites, leading to significant NEP increases under fertilization, while throughfall reduction increased NEP at FL and VA due to no effect on NPP and negative effect on RS. Fertilization offset the negative effect of throughfall reduction on NEP in the fertilization x throughfall reduction treatment. All sites were significant carbon sinks, accumulating from 3.5 to 24 Mg C ha-1 in a 3 year period under a range of climatic conditions, age and treatments.

Satellite Driven Estimation of Primary Productivity of Agroecosystems in India

NASA Astrophysics Data System (ADS)

Patel, N. R.; Dadhwal, V. K.; Agrawal, S.; Saha, S. K.

2011-08-01

Earth observation driven ecosystem modeling have played a major role in estimation of carbon budget components such as gross primary productivity (GPP) and net primary production (NPP) over terrestrial ecosystems, including agriculture. The present study therefore evaluate satellite-driven vegetation photosynthesis (VPM) model for GPP estimation over agro-ecosystems in India by using time series of the Normalized Difference Vegetation Index (NDVI) from SPOT-VEGETATION, cloud cover observation from MODIS, coarse-grid C3/C4 crop fraction and decadal grided databases of maximum and minimum temperatures. Parameterization of VPM parameters e.g. maximum light use efficiency (ɛ*) and Tscalar was done based on eddy-covariance measurements and literature survey. Incorporation of C3/C4 crop fraction is a modification to commonly used constant maximum LUE. Modeling results from VPM captured very well the geographical pattern of GPP and NPP over cropland in India. Well managed agro-ecosystems in Trans-Gangetic and upper Indo-Gangetic plains had the highest magnitude of GPP with peak GPP during kharif occurs in sugarcane-wheat system (western UP) and it occurs in rice-wheat system (Punjab) during Rabi season. Overall, croplands in these plains had more annual GPP (> 1000 g C m-2) and NPP (> 600 g C m-2) due to input-intensive cultivation. Desertic tracts of western Rajasthan showed the least GPP and NPP values. Country-level contribution of croplands to national GPP and NPP amounts to1.34 Pg C year-1 and 0.859 Pg C year-1, respectively. Modeled estimates of cropland NPP agrees well with ground-based estimates for north-western India (R2 = 0.63 and RMSE = 108 g C m-2). Future research will focus on evaluating the VPM model with medium resolution sensors such as AWiFS and MODIS for rice-wheat system and validating with eddy-covariance measurements.

Future supply and demand of net primary production in the Sahel

NASA Astrophysics Data System (ADS)

Sallaba, Florian; Olin, Stefan; Engström, Kerstin; Abdi, Abdulhakim M.; Boke-Olén, Niklas; Lehsten, Veiko; Ardö, Jonas; Seaquist, Jonathan W.

2017-12-01

In the 21st century, climate change in combination with increasing demand, mainly from population growth, will exert greater pressure on the ecosystems of the Sahel to supply food and feed resources. The balance between supply and demand, defined as the annual biomass required for human consumption, serves as a key metric for quantifying basic resource shortfalls over broad regions.Here we apply an exploratory modelling framework to analyse the variations in the timing and geography of different NPP (net primary production) supply-demand scenarios, with distinct assumptions determining supply and demand, for the 21st century Sahel. We achieve this by coupling a simple NPP supply model forced with projections from four representative concentration pathways with a global, reduced-complexity demand model driven by socio-economic data and assumptions derived from five shared socio-economic pathways.For the scenario that deviates least from current socio-economic and climate trends, we find that per capita NPP begins to outstrip supply in the 2040s, while by 2050 half the countries in the Sahel experience NPP shortfalls. We also find that despite variations in the timing of the onset of NPP shortfalls, demand cannot consistently be met across the majority of scenarios. Moreover, large between-country variations are shown across the scenarios, in which by the year 2050 some countries consistently experience shortage or surplus, while others shift from surplus to shortage. At the local level (i.e. grid cell), hotspots of total NPP shortfall consistently occur in the same locations across all scenarios but vary in size and magnitude. These hotspots are linked to population density and high demand. For all scenarios, total simulated NPP supply doubles by 2050 but is outpaced by increasing demand due to a combination of population growth and the adoption of diets rich in animal products. Finally, variations in the timing of the onset and end of supply shortfalls stem from the assumptions that underpin the shared socio-economic pathways rather than the representative concentration pathways.Our results suggest that the UN sustainable development goals for eradicating hunger are at high risk for failure. This emphasizes the importance of policy interventions such as the implementation of sustainable and healthy diets, family planning, reducing yield gaps, and encouraging the transfer of resources to impoverished areas via trade relations.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Boyd, P.W.; Gall, M.P.; Silver, M.W.

A central question addressed by the VERTIGO (VERtical Transport In the Global Ocean) study was 'What controls the efficiency of particle export between the surface and subsurface ocean'? Here, we present data from sites at ALOHA (N Central Pacific Gyre) and K2 (NW subarctic Pacific) on phytoplankton processes, and relate them via a simple planktonic foodweb model, to subsurface particle export (150-500 m). Three key factors enable quantification of the surface-subsurface coupling: a sampling design to overcome the temporal lag and spatial displacement between surface and subsurface processes; data on the size-partitioning of Net Primary Production (NPP) and subsequent transformationsmore » prior to export; estimates of the ratio of algal- to faecal-mediated vertical export flux. At ALOHA, phytoplankton were characterized by low stocks, NPP, F{sub v}/F{sub m} (N-limited), and were dominated by picoplankton. The HNLC waters at K2 were characterized by both two-fold changes in NPP and floristic shifts (high to low proportion of diatoms) between deployment 1 and 2. Prediction of export exiting the euphotic zone was based on size-partitioning of NPP, a copepod-dominated foodweb and a ratio of 0.2 (ALOHA) and 0.1 (K2) for algal:faecal particle flux. Predicted export was 20-22 mg POC m{sup -2} d{sup -1} at ALOHA (i.e. 10-11% NPP (0-125 m); 1.1-1.2 x export flux at 150 m (E{sub 150}). At K2, export was 111 mg C m{sup -2} d{sup -1} (21% NPP (0-50 m); 1.8 x E{sub 150}) and 33 mg POC m{sup -2} d{sup -1} (11% NPP, 0-55 m); 1.4 x E{sub 150}) for deployments 1 and 2, respectively. This decrease in predicted export at K2 matches the observed trend for E{sub 150}. Also, the low attenuation of export flux from 60 to 150 m is consistent with that between 150 to 500 m. This strong surface-subsurface coupling suggests that phytoplankton productivity and floristics play a key role at K2 in setting export flux, and moreover that pelagic particle transformations by grazers strongly influence to what extent sinking particles are further broken down in the underlying waters of the Twilight Zone.« less

Quantifying the surface subsurface biogeochemical coupling during the VERTIGO ALOHA and K2 studies

NASA Astrophysics Data System (ADS)

Boyd, Philip W.; Gall, Mark P.; Silver, Mary W.; Coale, Susan L.; Bidigare, Robert R.; Bishop, James L. K. B.

2008-07-01

A central question addressed by the VERtical Transport In the Global Ocean (VERTIGO) study was 'What controls the efficiency of particle export between the surface and subsurface ocean'? Here, we present data from sites at ALOHA (N Central Pacific Gyre) and K2 (NW subarctic Pacific) on phytoplankton processes, and relate them via a simple planktonic foodweb model, to subsurface particle export (150-500 m). Three key factors enable quantification of the surface-subsurface coupling: a sampling design to overcome the temporal lag and spatial displacement between surface and subsurface processes; data on the size partitioning of net primary production (NPP) and subsequent transformations prior to export; estimates of the ratio of algal- to faecal-mediated vertical export flux. At ALOHA, phytoplankton were characterized by low stocks, NPP, Fv/ Fm (N-limited), and were dominated by picoplankton. The HNLC waters at K2 were characterized by both two-fold changes in NPP and floristic shifts (high to low proportion of diatoms) between deployment 1 and 2. Prediction of export exiting the euphotic zone was based on size partitioning of NPP, a copepod-dominated foodweb and a ratio of 0.2 (ALOHA) and 0.1 (K2) for algal:faecal particle flux. Predicted export was 20-22 mg POC m -2 d -1 at ALOHA (i.e. 10-11% NPP (0-125 m); 1.1-1.2×export flux at 150 m ( E150). At K2, export was 111 mg C m -2 d -1 (21% NPP (0-50 m); 1.8× E150) and 33 mg POC m -2 d -1 (11% NPP, 0-55 m); 1.4× E150) for deployments 1 and 2, respectively. This decrease in predicted export at K2 matches the observed trend for E150. Also, the low attenuation of export flux from 60 to 150 m is consistent with that between 150 and 500 m. This strong surface-subsurface coupling suggests that phytoplankton productivity and floristics play a key role at K2 in setting export flux, and moreover that pelagic particle transformations by grazers strongly influence to what extent sinking particles are further broken down in the underlying waters of the Twilight Zone.

An Assessment of Integrated Health Management (IHM) Frameworks

DOE Office of Scientific and Technical Information (OSTI.GOV)

N. Lybeck; M. Tawfik; L. Bond

In order to meet the ever increasing demand for energy, the United States nuclear industry is turning to life extension of existing nuclear power plants (NPPs). Economically ensuring the safe, secure, and reliable operation of aging nuclear power plants presents many challenges. The 2009 Light Water Reactor Sustainability Workshop identified online monitoring of active and structural components as essential to the better understanding and management of the challenges posed by aging nuclear power plants. Additionally, there is increasing adoption of condition-based maintenance (CBM) for active components in NPPs. These techniques provide a foundation upon which a variety of advanced onlinemore » surveillance, diagnostic, and prognostic techniques can be deployed to continuously monitor and assess the health of NPP systems and components. The next step in the development of advanced online monitoring is to move beyond CBM to estimating the remaining useful life of active components using prognostic tools. Deployment of prognostic health management (PHM) on the scale of a NPP requires the use of an integrated health management (IHM) framework - a software product (or suite of products) used to manage the necessary elements needed for a complete implementation of online monitoring and prognostics. This paper provides a thoughtful look at the desirable functions and features of IHM architectures. A full PHM system involves several modules, including data acquisition, system modeling, fault detection, fault diagnostics, system prognostics, and advisory generation (operations and maintenance planning). The standards applicable to PHM applications are indentified and summarized. A list of evaluation criteria for PHM software products, developed to ensure scalability of the toolset to an environment with the complexity of a NPP, is presented. Fourteen commercially available PHM software products are identified and classified into four groups: research tools, PHM system development tools, deployable architectures, and peripheral tools.« less

Seismic performance assessment of base-isolated safety-related nuclear structures

USGS Publications Warehouse

Huang, Y.-N.; Whittaker, A.S.; Luco, N.

2010-01-01

Seismic or base isolation is a proven technology for reducing the effects of earthquake shaking on buildings, bridges and infrastructure. The benefit of base isolation has been presented in terms of reduced accelerations and drifts on superstructure components but never quantified in terms of either a percentage reduction in seismic loss (or percentage increase in safety) or the probability of an unacceptable performance. Herein, we quantify the benefits of base isolation in terms of increased safety (or smaller loss) by comparing the safety of a sample conventional and base-isolated nuclear power plant (NPP) located in the Eastern U.S. Scenario- and time-based assessments are performed using a new methodology. Three base isolation systems are considered, namely, (1) Friction Pendulum??? bearings, (2) lead-rubber bearings and (3) low-damping rubber bearings together with linear viscous dampers. Unacceptable performance is defined by the failure of key secondary systems because these systems represent much of the investment in a new build power plant and ensure the safe operation of the plant. For the scenario-based assessments, the probability of unacceptable performance is computed for an earthquake with a magnitude of 5.3 at a distance 7.5 km from the plant. For the time-based assessments, the annual frequency of unacceptable performance is computed considering all potential earthquakes that may occur. For both assessments, the implementation of base isolation reduces the probability of unacceptable performance by approximately four orders of magnitude for the same NPP superstructure and secondary systems. The increase in NPP construction cost associated with the installation of seismic isolators can be offset by substantially reducing the required seismic strength of secondary components and systems and potentially eliminating the need to seismically qualify many secondary components and systems. ?? 2010 John Wiley & Sons, Ltd.

Moderate forest disturbance as a stringent test for gap and big-leaf models

NASA Astrophysics Data System (ADS)

Bond-Lamberty, B.; Fisk, J. P.; Holm, J. A.; Bailey, V.; Bohrer, G.; Gough, C. M.

2015-01-01

Disturbance-induced tree mortality is a key factor regulating the carbon balance of a forest, but tree mortality and its subsequent effects are poorly represented processes in terrestrial ecosystem models. It is thus unclear whether models can robustly simulate moderate (non-catastrophic) disturbances, which tend to increase biological and structural complexity and are increasingly common in aging US forests. We tested whether three forest ecosystem models - Biome-BGC (BioGeochemical Cycles), a classic big-leaf model, and the ZELIG and ED (Ecosystem Demography) gap-oriented models - could reproduce the resilience to moderate disturbance observed in an experimentally manipulated forest (the Forest Accelerated Succession Experiment in northern Michigan, USA, in which 38% of canopy dominants were stem girdled and compared to control plots). Each model was parameterized, spun up, and disturbed following similar protocols and run for 5 years post-disturbance. The models replicated observed declines in aboveground biomass well. Biome-BGC captured the timing and rebound of observed leaf area index (LAI), while ZELIG and ED correctly estimated the magnitude of LAI decline. None of the models fully captured the observed post-disturbance C fluxes, in particular gross primary production or net primary production (NPP). Biome-BGC NPP was correctly resilient but for the wrong reasons, and could not match the absolute observational values. ZELIG and ED, in contrast, exhibited large, unobserved drops in NPP and net ecosystem production. The biological mechanisms proposed to explain the observed rapid resilience of the C cycle are typically not incorporated by these or other models. It is thus an open question whether most ecosystem models will simulate correctly the gradual and less extensive tree mortality characteristic of moderate disturbances.

Moderate forest disturbance as a stringent test for gap and big-leaf models

DOE PAGES

Bond-Lamberty, Benjamin; Fisk, Justin P.; Holm, Jennifer; ...

2015-01-27

Disturbance-induced tree mortality is a key factor regulating the carbon balance of a forest, but tree mortality and its subsequent effects are poorly represented processes in terrestrial ecosystem models. It is thus unclear whether models can robustly simulate moderate (non-catastrophic) disturbances, which tend to increase biological and structural complexity and are increasingly common in aging US forests. We tested whether three forest ecosystem models – Biome-BGC (BioGeochemical Cycles), a classic big-leaf model, and the ZELIG and ED (Ecosystem Demography) gap-oriented models – could reproduce the resilience to moderate disturbance observed in an experimentally manipulated forest (the Forest Accelerated Succession Experimentmore » in northern Michigan, USA, in which 38% of canopy dominants were stem girdled and compared to control plots). Each model was parameterized, spun up, and disturbed following similar protocols and run for 5 years post-disturbance. The models replicated observed declines in aboveground biomass well. Biome-BGC captured the timing and rebound of observed leaf area index (LAI), while ZELIG and ED correctly estimated the magnitude of LAI decline. None of the models fully captured the observed post-disturbance C fluxes, in particular gross primary production or net primary production (NPP). Biome-BGC NPP was correctly resilient but for the wrong reasons, and could not match the absolute observational values. ZELIG and ED, in contrast, exhibited large, unobserved drops in NPP and net ecosystem production. The biological mechanisms proposed to explain the observed rapid resilience of the C cycle are typically not incorporated by these or other models. It is thus an open question whether most ecosystem models will simulate correctly the gradual and less extensive tree mortality characteristic of moderate disturbances.« less

Importance of vegetation distribution for future carbon balance

NASA Astrophysics Data System (ADS)

Ahlström, A.; Xia, J.; Arneth, A.; Luo, Y.; Smith, B.

2015-12-01

Projections of future terrestrial carbon uptake vary greatly between simulations. Net primary production (NPP), wild fires, vegetation dynamics (including biome shifts) and soil decomposition constitute the main processes governing the response of the terrestrial carbon cycle in a changing climate. While primary production and soil respiration are relatively well studied and implemented in all global ecosystem models used to project the future land sink of CO2, vegetation dynamics are less studied and not always represented in global models. Here we used a detailed second generation dynamic global vegetation model with advanced representation of vegetation growth and mortality and the associated turnover and proven skill in predicting vegetation distribution and succession. We apply an emulator that describes the carbon flows and pools exactly as in simulations with the full model. The emulator simulates ecosystem dynamics in response to 13 different climate or Earth system model simulations from the CMIP5 ensemble under RCP8.5 radiative forcing at year 2085. We exchanged carbon cycle processes between these 13 simulations and investigate the changes predicted by the emulator. This method allowed us to partition the entire ensemble carbon uptake uncertainty into individual processes. We found that NPP, vegetation dynamics (including biome shifts, wild fires and mortality) and soil decomposition rates explained 49%, 17% and 33% respectively of uncertainties in modeled global C-uptake. Uncertainty due to vegetation dynamics was further partitioned into stand-clearing disturbances (16%), wild fires (0%), stand dynamics (7%), reproduction (10%) and biome shifts (67%) globally. We conclude that while NPP and soil decomposition rates jointly account for 83% of future climate induced C-uptake uncertainties, vegetation turnover and structure, dominated by shifts in vegetation distribution, represent a significant fraction globally and regionally (tropical forests: 40%), strongly motivating their representation and analysis in future C-cycle studies.

Observations of Ocean Primary Productivity Using MODIS

NASA Technical Reports Server (NTRS)

Esaias, Wayne E.; Abbott, Mark R.; Koblinsky, Chester J. (Technical Monitor)

2001-01-01

Measuring the magnitude and variability of oceanic net primary productivity (NPP) represents a key advancement toward our understanding of the dynamics of marine ecosystems and the role of the ocean in the global carbon cycle. MODIS observations make two new contributions in addition to continuing the bio-optical time series begun with Orbview-2's SeaWiFS sensor. First, MODIS provides weekly estimates of global ocean net primary productivity on weekly and annual time periods, and annual empirical estimates of carbon export production. Second, MODIS provides additional insight into the spatial and temporal variations in photosynthetic efficiency through the direct measurements of solar-stimulated chlorophyll fluorescence. The two different weekly productivity indexes (first developed by Behrenfeld & Falkowski and by Yoder, Ryan and Howard) are used to derive daily productivity as a function of chlorophyll biomass, incident daily surface irradiance, temperature, euphotic depth, and mixed layer depth. Comparisons between these two estimates using both SeaWiFS and MODIS data show significant model differences in spatial distribution after allowance for the different integration depths. Both estimates are strongly dependence on the accuracy of the chlorophyll determination. In addition, an empirical approach is taken on annual scales to estimate global NPP and export production. Estimates of solar stimulated fluorescence efficiency from chlorophyll have been shown to be inversely related to photosynthetic efficiency by Abbott and co-workers. MODIS provides the first global estimates of oceanic chlorophyll fluorescence, providing an important proof of concept. MODIS observations are revealing spatial patterns of fluorescence efficiency which show expected variations with phytoplankton photo-physiological parameters as measured during in-situ surveys. This has opened the way for research into utilizing this information to improve our understanding of oceanic NPP variability. Deriving the ocean bio-optical properties places severe demands on instrument performance (especially band to band precision) and atmospheric correction. Improvements in MODIS instrument characterization and calibration over the first 16 mission months have greatly improved the accuracy of the chlorophyll input fields and FLH, and therefore the estimates of NPP and fluorescence efficiency. Annual estimates now show the oceanic NPP accounts for 40-50% of the global total NPP, with significant interannual variations related to large scale ocean processes. Spatial variations in ocean NPP, and exported production, have significant effects on exchange of CO2 between the ocean and atmosphere. Further work is underway to improve both the primary productivity model functions, and to refine our understanding of the relationships between fluorescence efficiency and NPP estimates. We expect that the MODIS instruments will prove extremely useful in assessing the time dependencies of oceanic carbon uptake and effects of iron enrichment, within the global carbon cycle.

Estimation of Mangrove Net Primary Production and Carbon Sequestration service using Light Use Efficiency model in the Sunderban Biosphere region, India

NASA Astrophysics Data System (ADS)

Sannigrahi, Srikanta; Sen, Somnath; Paul, Saikat

2016-04-01

Net Primary Production (NPP) of mangrove ecosystem and its capacity to sequester carbon from the atmosphere may be used to quantify the regulatory ecosystem services. Three major group of parameters has been set up as BioClimatic Parameters (BCP): (Photosynthetically Active Radiation (PAR), Absorbed PAR (APAR), Fraction of PAR (FPAR), Photochemical Reflectance Index (PRI), Light Use Efficiency (LUE)), BioPhysical Parameters (BPP) :(Normalize Difference Vegetation Index (NDVI), scaled NDVI, Enhanced Vegetation Index (EVI), scaled EVI, Optimised and Modified Soil Adjusted Vegetation Index (OSAVI, MSAVI), Leaf Area Index (LAI)), and Environmental Limiting Parameters (ELP) (Temperature Stress (TS), Land Surface Water Index (LSWI), Normalize Soil Water Index (NSWI), Water Stress Scalar (WS), Inversed WS (iWS) Land Surface Temperature (LST), scaled LST, Vapor Pressure Deficit (VPD), scaled VPD, and Soil Water Deficit Index (SWDI)). Several LUE models namely Carnegie Ames Stanford Approach (CASA), Eddy Covariance - LUE (EC-LUE), Global Production Efficiency Model (GloPEM), Vegetation Photosynthesis Model (VPM), MOD NPP model, Temperature and Greenness Model (TG), Greenness and Radiation model (GR) and MOD17 was adopted in this study to assess the spatiotemporal nature of carbon fluxes. Above and Below Ground Biomass (AGB & BGB) was calculated using field based estimation of OSAVI and NDVI. Microclimatic zonation has been set up to assess the impact of coastal climate on environmental limiting factors. MODerate Resolution Imaging Spectroradiometer (MODIS) based yearly Gross Primary Production (GPP) and NPP product MOD17 was also tested with LUE based results with standard model validation statistics: Root Mean Square of Error (RMSE), Mean Absolute Error (MEA), Bias, Coefficient of Variation (CV) and Coefficient of Determination (R2). The performance of CASA NPP was tested with the ground based NPP with R2 = 0.89 RMSE = 3.28 P = 0.01. Among the all adopted models, EC-LUE and VPM models has explained the maximum variances (>80%) in comparison to the other model. Study result has also showed that the BPP has explained the maximum model variances (>93%) followed by BCP (>65%) and ELP (>50%). Scaled WS, iWS, LST, VPD, NDVI was performed better in a minimum ELP condition whereas surface moisture and wetness was highly correlated with the AGB and NPP (R2 = 0.86 RMSE = 1.83). During this study period (2000-2013), it was found that there was a significantly declining trend (R2 = 0.32 P = 0.05) of annual NPP and the maximum decrease was found in the eastern part where built-up area was mainly accounted for reduction of NPP. BCP are explained higher variances (>80%) in the optimum climatic condition exist along the coastal stretches in comparison to the landward extent (>45%).

Local network deployed around the Kozloduy NPP - a useful tool for seismological monitoring

NASA Astrophysics Data System (ADS)

Solakov, Dimcho; Simeonova, Stela; Dimitrova, Liliya; Slavcheva, Krasimira; Raykova, Plamena; Popova, Maria; Georgiev, Ivan

2015-04-01

Radiation risks may transcend national borders, and international cooperation serves to promote and enhance safety globally by exchanging experience and by improving capabilities to control hazards, to prevent accidents, to respond to emergencies and to mitigate any harmful consequences. International safety standards provide support for states in meeting their obligations under general principles of international law, such as those relating to environmental protection. Seismic safety is a key element of NPP safe operation. Safety and security measures have in common the aim of protecting human life and health and the environment. The Kozloduy NPP site is located in the stable part of the Moesian platform (area of about 50000 km2). From seismological point of view the Moesian platform is the most quite area on the territory of Bulgaria. There are neither historical nor instrumental earthquakes with M>4.5 occurred within the platform. The near region (area with radial extent of 30 km) of the NPP site is characterized with very low seismic activity. The strongest recorded quake is the 1987 earthquake МS=3.6, localized 22 km northwest of the Kozloduy NPP site on the territory of Romania. In line with international practice, the geological, geophysical and seismological characteristics of the region around the site have been investigated for the purpose of evaluating the seismic hazards at the NPP site. A local network (LSN) of sensitive seismographs having a recording capability for micro-earthquakes have been installed around Kozloduy NPP and operated since 1997. The operation and data processing, data interpretation, and reporting of the local micro-earthquake network are linked to the national seismic network (NOTSSI). A real-time data transfer from stations to National Data Center (in Sofia) was implemented using the VPN and MAN networks of the Bulgarian Telecommunication. Real-time and interactive data processing are performed by the Seismic Network Data Processor (SNDP) software package. Strong motion accelerographs and GPS instrumentation are installed permanently within the near region. The equipment is periodically upgraded and calibrated to provide adequate information in line with updated international operational practice. The results of the 17 years of operation of LSN "Kozloduy" are presented in the present study. The multiple studies carried out indicate that LSN jointly with NOTSSI provide reliable registration of weak seismicity in the near (30 km) region of NPP site. Earthquakes recorded within and near the network are carefully analyzed in connection with seismotectonic studies of the near region. The seismological database acquired is homogeneous for the entire region to the extent possible or, at a minimum, is sufficiently complete for characterizing, from a seismotectonic point of view, features relevant to the site.

The establishment of a production-ready manufacturing process utilizing thin silicon substrates for solar cells

NASA Technical Reports Server (NTRS)

Pryor, R. A.

1980-01-01

Three inch diameter Czochralski silicon substrates sliced directly to 5 mil, 8 mil, and 27 mil thicknesses with wire saw techniques were procured. Processing sequences incorporating either diffusion or ion implantation technologies were employed to produce n+p or n+pp+ solar cell structures. These cells were evaluated for performance, ease of fabrication, and cost effectiveness. It was determined that the use of 7 mil or even 4 mil wafers would provide near term cost reductions for solar cell manufacturers.

Estimating aboveground net primary productivity in forest-dominated ecosystems

Treesearch

Brian D. Kloeppel; Mark E. Harmon; Timothy J. Fahey

2007-01-01

The measurement of net primary productivity (NPP) in forest ecosystems presents a variety of challenges because of the large and complex dimensions of trees and the difficulties of quantifying several components of NPP. As summarized by Clark et al. (2001a), these methodological challenges can be overcome, and more reliable spatial and temporal comparisons can be...

COMBINING LIDAR ESTIMATES OF BIOMASS AND LANDSAT ESTIMATES OF STAND AGE FOR SPATIALLY EXTENSIVE VALIDATION OF MODELED FOREST PRODUCTIVITY. (R828309)

EPA Science Inventory

Extensive estimates of forest productivity are required to understand the
relationships between shifting land use, changing climate and carbon storage
and fluxes. Aboveground net primary production of wood (NPP_Aw) is a major component
of total NPP and...

Calbuco Volcano Erupts in Southern Chile

NASA Image and Video Library

2015-04-24

Calbuco Volcano in southern Chile has erupted for the first time since 1972, with the last major eruption occurring in 1961 that sent ash columns 12-15 kilometers high. This image was taken by the Suomi NPP satellite's VIIRS instrument in a high resolution infrared channel around 0515Z on April 23, 2015. Credit: NOAA/NASA/NPP/VIIRS

Canopy leaf area constrains [CO2]-induced enhancement of productivity and partitioning among aboveground carbon pools.

Treesearch

Heather R. McCarthy; Ram Oren; Adrien C. Finzi; Kurt H. Johnsen

2006-01-01

Net primary productivity (NPP) is enhanced under future atmospheric [CO2] in temperate forests representing a broad range of productivity. Yet questions remain in regard to how elevated [CO2]-induced NPP enhancement may be affected by climatic variations and limiting nutrient resources, as well as how this additional...

Suomi NPP View of a Strong Midwest Cyclone

NASA Image and Video Library

2014-02-25

A strong late-winter cyclone brought significant snows and blizzard conditions to the upper Great Lakes/northern Plains on 21 February 2014. In the warm sector of the storm, there were numerous reports of tornadoes, large hail, and damaging winds in the eastern US. Suomi NPP viewed the storm multiple times, including just before 1800 UTC on 21 February. Credit: NASA/Goddard/UWM/SSEC/CIMSS/Suomi NPP NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

Chronic lymphocytic leukemia patients exposed to ionizing radiation due to the Chernobyl NPP accident--with focus on immunoglobulin heavy chain gene analysis.

PubMed

Abramenko, Iryna; Bilous, Nadia; Chumak, Anatoliy; Davidova, Ekaterina; Kryachok, Iryna; Martina, Zoya; Nechaev, Stanislav; Dyagil, Iryna; Bazyka, Dmytriy; Bebeshko, Vladimir

2008-04-01

Clinical data and immunoglobulin variable heavy chain (IgVH) gene configuration were analyzed in 47 CLL patients, exposed to ionizing radiation (IR) due to Chernobyl NPP accident, and 141 non-exposed patients. Clean-up workers of the second quarter of 1986 (n=19) were picked out as separate group with the highest number of unmutated cases (94.4%), increased usage of IgVH1-69 (33.3%) and IgVH3-21 (16.7%) genes, high frequency of secondary solid tumors (6 cases) and Richter transformation (4 cases). These preliminary data suggest that CLL in the most suffered contingent due to Chernobyl NPP accident might have some specific features.

A review of nondestructive examination technology for polyethylene pipe in nuclear power plant

NASA Astrophysics Data System (ADS)

Zheng, Jinyang; Zhang, Yue; Hou, Dongsheng; Qin, Yinkang; Guo, Weican; Zhang, Chuck; Shi, Jianfeng

2018-05-01

Polyethylene (PE) pipe, particularly high-density polyethylene (HDPE) pipe, has been successfully utilized to transport cooling water for both non-safety- and safety-related applications in nuclear power plant (NPP). Though ASME Code Case N755, which is the first code case related to NPP HDPE pipe, requires a thorough nondestructive examination (NDE) of HDPE joints. However, no executable regulations presently exist because of the lack of a feasible NDE technique for HDPE pipe in NPP. This work presents a review of current developments in NDE technology for both HDPE pipe in NPP with a diameter of less than 400 mm and that of a larger size. For the former category, phased array ultrasonic technique is proven effective for inspecting typical defects in HDPE pipe, and is thus used in Chinese national standards GB/T 29460 and GB/T 29461. A defect-recognition technique is developed based on pattern recognition, and a safety assessment principle is summarized from the database of destructive testing. On the other hand, recent research and practical studies reveal that in current ultrasonic-inspection technology, the absence of effective ultrasonic inspection for large size was lack of consideration of the viscoelasticity effect of PE on acoustic wave propagation in current ultrasonic inspection technology. Furthermore, main technical problems were analyzed in the paper to achieve an effective ultrasonic test method in accordance to the safety and efficiency requirements of related regulations and standards. Finally, the development trend and challenges of NDE test technology for HDPE in NPP are discussed.

Effects of sea ice cover on satellite-detected primary production in the Arctic Ocean

PubMed Central

Lee, Zhongping; Mitchell, B. Greg; Nevison, Cynthia D.

2016-01-01

The influence of decreasing Arctic sea ice on net primary production (NPP) in the Arctic Ocean has been considered in multiple publications but is not well constrained owing to the potentially large errors in satellite algorithms. In particular, the Arctic Ocean is rich in coloured dissolved organic matter (CDOM) that interferes in the detection of chlorophyll a concentration of the standard algorithm, which is the primary input to NPP models. We used the quasi-analytic algorithm (Lee et al. 2002 Appl. Opti. 41, 5755−5772. (doi:10.1364/AO.41.005755)) that separates absorption by phytoplankton from absorption by CDOM and detrital matter. We merged satellite data from multiple satellite sensors and created a 19 year time series (1997–2015) of NPP. During this period, both the estimated annual total and the summer monthly maximum pan-Arctic NPP increased by about 47%. Positive monthly anomalies in NPP are highly correlated with positive anomalies in open water area during the summer months. Following the earlier ice retreat, the start of the high-productivity season has become earlier, e.g. at a mean rate of −3.0 d yr−1 in the northern Barents Sea, and the length of the high-productivity period has increased from 15 days in 1998 to 62 days in 2015. While in some areas, the termination of the productive season has been extended, owing to delayed ice formation, the termination has also become earlier in other areas, likely owing to limited nutrients. PMID:27881759

[Parameter sensitivity of simulating net primary productivity of Larix olgensis forest based on BIOME-BGC model].

PubMed

He, Li-hong; Wang, Hai-yan; Lei, Xiang-dong

2016-02-01

Model based on vegetation ecophysiological process contains many parameters, and reasonable parameter values will greatly improve simulation ability. Sensitivity analysis, as an important method to screen out the sensitive parameters, can comprehensively analyze how model parameters affect the simulation results. In this paper, we conducted parameter sensitivity analysis of BIOME-BGC model with a case study of simulating net primary productivity (NPP) of Larix olgensis forest in Wangqing, Jilin Province. First, with the contrastive analysis between field measurement data and the simulation results, we tested the BIOME-BGC model' s capability of simulating the NPP of L. olgensis forest. Then, Morris and EFAST sensitivity methods were used to screen the sensitive parameters that had strong influence on NPP. On this basis, we also quantitatively estimated the sensitivity of the screened parameters, and calculated the global, the first-order and the second-order sensitivity indices. The results showed that the BIOME-BGC model could well simulate the NPP of L. olgensis forest in the sample plot. The Morris sensitivity method provided a reliable parameter sensitivity analysis result under the condition of a relatively small sample size. The EFAST sensitivity method could quantitatively measure the impact of simulation result of a single parameter as well as the interaction between the parameters in BIOME-BGC model. The influential sensitive parameters for L. olgensis forest NPP were new stem carbon to new leaf carbon allocation and leaf carbon to nitrogen ratio, the effect of their interaction was significantly greater than the other parameter' teraction effect.

Land, Cryosphere, and Nighttime Environmental Products from Suomi NPP VIIRS: Overview and Status

NASA Technical Reports Server (NTRS)

Roman, Miguel O.; Justice, Chris; Csiszar, Ivan

2014-01-01

The Visible Infrared Imaging Radiometer Suite (VIIRS) instrument was launched in October 2011 as part of the Suomi National Polar-orbiting Partnership (S-NPP: http://npp.gsfc.nasa.gov/). VIIRS was designed to improve upon the capabilities of the operational Advanced Very High Resolution Radiometer (AVHRR) and provide observation continuity with NASA's Earth Observing System's (EOS) Moderate Resolution Imaging Spectroradiometer (MODIS). Since the VIIRS first-light images were received in November 2011, NASA and NOAA funded scientists have been working to evaluate the instrument performance and derived products to meet the needs of the NOAA operational users and the NASA science community. NOAA's focus has been on refining a suite of operational products known as Environmental Data Records (EDRs), which were developed according to project specifications under the former National Polar-orbiting Environmental Satellite System (NPOESS). The NASA S-NPP Science Team has focused on evaluating the EDRs for science use, developing and testing additional products to meet science data needs and providing MODIS data product continuity. This paper will present to-date findings of the NASA Science Team's evaluation of the VIIRS Land and Cryosphere EDRs, specifically Surface Reflectance, Land Surface Temperature, Surface Albedo, Vegetation Indices, Surface Type, Active Fires, Snow Cover, Ice Surface Temperature, and Sea Ice Characterization (http://viirsland.gsfc.nasa.gov/index.html). The paper will also discuss new capabilities being developed at NASA's Land Product Evaluation and Test Element (http://landweb.nascom.nasa.gov/NPP_QA/); including downstream data and products derived from the VIIRS Day/Night Band (DNB).

Broiler diet modification and litter storage: impacts on phosphorus in litters, soils, and runoff.

PubMed

McGrath, Joshua M; Sims, J Thomas; Maguire, Rory O; Saylor, William W; Angel, C Roselina; Turner, Benjamin L

2005-01-01

Modifying broiler diets to mitigate water quality concerns linked to excess phosphorus (P) in regions of intensive broiler production has recently increased. Our goals were to evaluate the effects of dietary modification, using phytase and reduced non-phytate phosphorus (NPP) supplementation, on P speciation in broiler litters, changes in litter P forms during long-term storage, and subsequent impacts of diets on P in runoff from litter-amended soils. Four diets containing two levels of NPP with and without phytase were fed to broilers in a three-flock floor pen study. After removal of the third flock, litters were stored for 440 d at their initial moisture content (MC; 24%) and at a MC of 40%. Litter P fractions and orthophosphate and phytate P concentrations were determined before and after storage. After storage, litters were incorporated with a sandy and silt loam and simulated rainfall was applied. Phytase and reduced dietary NPP significantly reduced litter total P. Reducing dietary NPP decreased water-extractable inorganic phosphorus (IP) and the addition of dietary phytase reduced NaOH- and HCl-extractable organic P in litter, which correlated well with orthophosphate and phytic acid measured by 31P nuclear magnetic resonance (NMR), respectively. Although dry storage caused little change in P speciation, wet storage increased concentrations of water-soluble IP, which increased reactive P in runoff from litter-amended soils. Therefore, diet modification with phytase and reduced NPP could be effective in reducing P additions on a watershed scale. Moreover, efforts to minimize litter MC during storage may reduce the potential for dissolved P losses in runoff.

Forest biomass, productivity and carbon cycling along a rainfall gradient in West Africa.

PubMed

Moore, Sam; Adu-Bredu, Stephen; Duah-Gyamfi, Akwasi; Addo-Danso, Shalom D; Ibrahim, Forzia; Mbou, Armel T; de Grandcourt, Agnès; Valentini, Riccardo; Nicolini, Giacomo; Djagbletey, Gloria; Owusu-Afriyie, Kennedy; Gvozdevaite, Agne; Oliveras, Imma; Ruiz-Jaen, Maria C; Malhi, Yadvinder

2018-02-01

Net Primary Productivity (NPP) is one of the most important parameters in describing the functioning of any ecosystem and yet it arguably remains a poorly quantified and understood component of carbon cycling in tropical forests, especially outside of the Americas. We provide the first comprehensive analysis of NPP and its carbon allocation to woody, canopy and root growth components at contrasting lowland West African forests spanning a rainfall gradient. Using a standardized methodology to study evergreen (EF), semi-deciduous (SDF), dry forests (DF) and woody savanna (WS), we find that (i) climate is more closely related with above and belowground C stocks than with NPP (ii) total NPP is highest in the SDF site, then the EF followed by the DF and WS and that (iii) different forest types have distinct carbon allocation patterns whereby SDF allocate in excess of 50% to canopy production and the DF and WS sites allocate 40%-50% to woody production. Furthermore, we find that (iv) compared with canopy and root growth rates the woody growth rate of these forests is a poor proxy for their overall productivity and that (v) residence time is the primary driver in the productivity-allocation-turnover chain for the observed spatial differences in woody, leaf and root biomass across the rainfall gradient. Through a systematic assessment of forest productivity we demonstrate the importance of directly measuring the main components of above and belowground NPP and encourage the establishment of more permanent carbon intensive monitoring plots across the tropics. © 2017 John Wiley & Sons Ltd.

Spatial patterns of ecosystem carbon residence time and NPP-driven carbon uptake in the conterminous United States

NASA Astrophysics Data System (ADS)

Zhou, Tao; Luo, Yiqi

2008-09-01

Ecosystem carbon (C) uptake is determined largely by C residence times and increases in net primary production (NPP). Therefore, evaluation of C uptake at a regional scale requires knowledge on spatial patterns of both residence times and NPP increases. In this study, we first applied an inverse modeling method to estimate spatial patterns of C residence times in the conterminous United States. Then we combined the spatial patterns of estimated residence times with a NPP change trend to assess the spatial patterns of regional C uptake in the United States. The inverse analysis was done by using the genetic algorithm and was based on 12 observed data sets of C pools and fluxes. Residence times were estimated by minimizing the total deviation between modeled and observed values. Our results showed that the estimated C residence times were highly heterogeneous over the conterminous United States, with most of the regions having values between 15 and 65 years; and the averaged C residence time was 46 years. The estimated C uptake for the whole conterminous United States was 0.15 P g C a-1. Large portions of the taken C were stored in soil for grassland and cropland (47-70%) but in plant pools for forests and woodlands (73-82%). The proportion of C uptake in soil was found to be determined primarily by C residence times and be independent of the magnitude of NPP increase. Therefore, accurate estimation of spatial patterns of C residence times is crucial for the evaluation of terrestrial ecosystem C uptake.

Diagnosing phosphorus limitations in natural terrestrial ecosystems in carbon cycle models

DOE PAGES

Sun, Yan; Peng, Shushi; Goll, Daniel S.; ...

2017-04-28

Most of the Earth System Models (ESMs) project increases in net primary productivity (NPP) and terrestrial carbon (C) storage during the 21st century. Despite empirical evidence that limited availability of phosphorus (P) may limit the response of NPP to increasing atmospheric CO 2, none of the ESMs used in the previous Intergovernmental Panel on Climate Change assessment accounted for P limitation. We diagnosed from ESM simulations the amount of P need to support increases in carbon uptake by natural ecosystems using two approaches: the demand derived from changes in C stocks and changes in NPP. The C stock-based additional Pmore » demand was estimated to range between -31 and 193 Tg P and between -89 and 262 Tg P for Representative Concentration Pathway (RCP) 2.6 and RCP8.5, respectively, with negative values indicating a P surplus. The NPP-based demand, which takes ecosystem P recycling into account, results in a significantly higher P demand of 648–1606 Tg P for RCP2.6 and 924–2110 Tg P for RCP8.5. We found that the P demand is sensitive to the turnover of P in decomposing plant material, explaining the large differences between the NPP-based demand and C stock-based demand. The discrepancy between diagnosed P demand and actual P availability (potential P deficit) depends mainly on the assumptions about availability of the different soil P forms. Altogether, future P limitation strongly depends on both soil P availability and P recycling on ecosystem scale.« less

Effects of sea ice cover on satellite-detected primary production in the Arctic Ocean.

PubMed

Kahru, Mati; Lee, Zhongping; Mitchell, B Greg; Nevison, Cynthia D

2016-11-01

The influence of decreasing Arctic sea ice on net primary production (NPP) in the Arctic Ocean has been considered in multiple publications but is not well constrained owing to the potentially large errors in satellite algorithms. In particular, the Arctic Ocean is rich in coloured dissolved organic matter (CDOM) that interferes in the detection of chlorophyll a concentration of the standard algorithm, which is the primary input to NPP models. We used the quasi-analytic algorithm (Lee et al 2002 Appl. Opti. 41, 5755-5772. (doi:10.1364/AO.41.005755)) that separates absorption by phytoplankton from absorption by CDOM and detrital matter. We merged satellite data from multiple satellite sensors and created a 19 year time series (1997-2015) of NPP. During this period, both the estimated annual total and the summer monthly maximum pan-Arctic NPP increased by about 47%. Positive monthly anomalies in NPP are highly correlated with positive anomalies in open water area during the summer months. Following the earlier ice retreat, the start of the high-productivity season has become earlier, e.g. at a mean rate of -3.0 d yr -1 in the northern Barents Sea, and the length of the high-productivity period has increased from 15 days in 1998 to 62 days in 2015. While in some areas, the termination of the productive season has been extended, owing to delayed ice formation, the termination has also become earlier in other areas, likely owing to limited nutrients. © 2016 The Author(s).

Site-level evaluation of satellite-based global terrestrial gross primary production and net primary production monitoring.

Treesearch

David P. Turner; William D. Ritts; Warren B. Cohen; Thomas K. Maeirsperger; Stith T. Gower; Al A. Kirschbaum; Steve W. Runnings; Maosheng Zhaos; Steven C. Wofsy; Allison L. Dunn; Beverly E. Law; John L. Campbell; Walter C. Oechel; Hyo Jung Kwon; Tilden P. Meyers; Eric E. Small; Shirley A. Kurc; John A. Gamon

2005-01-01

Operational monitoring of global terrestrial gross primary production (GPP) and net primary production (NPP) is now underway using imagery from the satellite-borne Moderate Resolution Imaging Spectroradiometer (MODIS) sensor. Evaluation of MODIS GPP and NPP products will require site-level studies across a range of biomes, with close attention to numerous scaling...

Nuclear Power Plant Module, NPP-1: Nuclear Power Cost Analysis.

ERIC Educational Resources Information Center

Whitelaw, Robert L.

The purpose of the Nuclear Power Plant Modules, NPP-1, is to determine the total cost of electricity from a nuclear power plant in terms of all the components contributing to cost. The plan of analysis is in five parts: (1) general formulation of the cost equation; (2) capital cost and fixed charges thereon; (3) operational cost for labor,…

Evaluation of Radiation Impacts of Spent Nuclear Fuel Storage (SNFS-2) of Chernobyl NPP - 13495

DOE Office of Scientific and Technical Information (OSTI.GOV)

Paskevych, Sergiy; Batiy, Valiriy; Sizov, Andriy

2013-07-01

Radiation effects are estimated for the operation of a new dry storage facility for spent nuclear fuel (SNFS-2) of Chernobyl NPP RBMK reactors. It is shown that radiation exposure during normal operation, design and beyond design basis accidents are minor and meet the criteria for safe use of radiation and nuclear facilities in Ukraine. (authors)

Aboveground production and nutrient circulation along a flooding gradient in a South Carolina Coastal Plain forest

Treesearch

B. Graeme Lockaby; William H. Conner

1999-01-01

Relative to effects of flooding, little is known about the influence of hydrology-nutrient interactions on aboveground net primary production (NPP) in forested wetlands. The authors found that nutrient circulation and NPP were closely related along a complex physical, chemical, and hydrologic gradient in a bottomland hardwood forest with four distinct communities....

Regional impacts of climate change and elevated carbon dioxide on forest productivity

Treesearch

Jennifer C. Jenkins; David W. Kicklighter; John D. Aber

2000-01-01

Net primary production (NPP) is defined as the rate at which carbon (C) is accumulated by autotrophs and is expressed as the difference between gross photosynthesis and autotrophic respiration. NPP is the resource providing for the growth and reproduction of all heterotrophs on Earth; as a result, it determines the planet's carrying capacity (Vitousek et al., 1986...

Combining LIDAR estimates of aboveground biomass and Landsat estimates of stand age for spatially extensive validation of modeled forest productivity.

Treesearch

M.A. Lefsky; D.P. Turner; M. Guzy; W.B. Cohen

2005-01-01

Extensive estimates of forest productivity are required to understand the relationships between shifting land use, changing climate and carbon storage and fluxes. Aboveground net primary production of wood (NPPAw) is a major component of total NPP and of net ecosystem production (NEP). Remote sensing of NPP and NPPAw is...

Pharmacokinetics of hederacoside C, an active ingredient in AG NPP709, in rats.

PubMed

Kim, Ju Myung; Yoon, Ji Na; Jung, Ji Won; Choi, Hye Duck; Shin, Young June; Han, Chang Kyun; Lee, Hye Suk; Kang, Hee Eun

2013-11-01

1. Hederacoside C (HDC) is one of the active ingredients in Hedera helix leaf extract (Ivy Ex.) and AG NPP709, a new botanical drug to treat acute respiratory infection and chronic inflammatory bronchitis. However, information regarding its pharmacokinetic properties remains limited. 2. Here, we report the pharmacokinetics of HDC in rats after intravenous administration of HDC (3, 12.5, and 25 mg/kg) and after oral administration of HDC, Ivy Ex., and AG NPP709 (equivalent to 12.5, 25, and 50 mg/kg HDC). 3. Linear pharmacokinetics of HDC were identified upon its intravenous administration at doses of 3-25 mg/kg. Intravenous administration of HDC results in relatively slow clearance (1.46-2.08 mL/min/kg) and a small volume of distribution at steady state (138-222 mL/kg), while oral administration results in a low absolute oral bioavailability (F) of 0.118-0.250%. The extremely low F of HDC may be due to poor absorption of HDC from the gastrointestinal (GI) tract and/or its decomposition therein. 4. The oral pharmacokinetics of HDC did not differ significantly among pure HDC, Ivy Ex., and AG NPP709.

An overview of the ENEA activities in the field of coupled codes NPP simulation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Parisi, C.; Negrenti, E.; Sepielli, M.

2012-07-01

In the framework of the nuclear research activities in the fields of safety, training and education, ENEA (the Italian National Agency for New Technologies, Energy and the Sustainable Development) is in charge of defining and pursuing all the necessary steps for the development of a NPP engineering simulator at the 'Casaccia' Research Center near Rome. A summary of the activities in the field of the nuclear power plants simulation by coupled codes is here presented with the long term strategy for the engineering simulator development. Specifically, results from the participation in international benchmarking activities like the OECD/NEA 'Kalinin-3' benchmark andmore » the 'AER-DYN-002' benchmark, together with simulations of relevant events like the Fukushima accident, are here reported. The ultimate goal of such activities performed using state-of-the-art technology is the re-establishment of top level competencies in the NPP simulation field in order to facilitate the development of Enhanced Engineering Simulators and to upgrade competencies for supporting national energy strategy decisions, the nuclear national safety authority, and the R and D activities on NPP designs. (authors)« less

Primary production sensitivity to phytoplankton light attenuation parameter increases with transient forcing

NASA Astrophysics Data System (ADS)

Kvale, Karin F.; Meissner, Katrin J.

2017-10-01

Treatment of the underwater light field in ocean biogeochemical models has been attracting increasing interest, with some models moving towards more complex parameterisations. We conduct a simple sensitivity study of a typical, highly simplified parameterisation. In our study, we vary the phytoplankton light attenuation parameter over a range constrained by data during both pre-industrial equilibrated and future climate scenario RCP8.5. In equilibrium, lower light attenuation parameters (weaker self-shading) shift net primary production (NPP) towards the high latitudes, while higher values of light attenuation (stronger shelf-shading) shift NPP towards the low latitudes. Climate forcing magnifies this relationship through changes in the distribution of nutrients both within and between ocean regions. Where and how NPP responds to climate forcing can determine the magnitude and sign of global NPP trends in this high CO2 future scenario. Ocean oxygen is particularly sensitive to parameter choice. Under higher CO2 concentrations, two simulations establish a strong biogeochemical feedback between the Southern Ocean and low-latitude Pacific that highlights the potential for regional teleconnection. Our simulations serve as a reminder that shifts in fundamental properties (e.g. light attenuation by phytoplankton) over deep time have the potential to alter global biogeochemistry.

A Model-Data Intercomparison of Carbon Fluxes, Pools, and LAI in the Community Land Model (CLM) and Alternative Carbon Allocation Schemes

NASA Astrophysics Data System (ADS)

Montane, F.; Fox, A. M.; Arellano, A. F.; Alexander, M. R.; Moore, D. J.

2016-12-01

Carbon (C) allocation to different plant tissues (leaves, stem and roots) remains a central challenge for understanding the global C cycle, as it determines C residence time. We used a diverse set of observations (AmeriFlux eddy covariance towers, biomass estimates from tree-ring data, and Leaf Area Index measurements) to compare C fluxes, pools, and Leaf Area Index (LAI) data with the Community Land Model (CLM). We ran CLM for seven temperate forests in North America (including evergreen and deciduous sites) between 1980 and 2013 using different C allocation schemes: i) standard C allocation scheme in CLM, which allocates C to the stem and leaves as a dynamic function of annual net primary productivity (NPP); ii) two fixed C allocation schemes, one representative of evergreen and the other one of deciduous forests, based on Luyssaert et al. 2007; iii) an alternative C allocation scheme, which allocated C to stem and leaves, and to stem and coarse roots, as a dynamic function of annual NPP, based on Litton et al. 2007. At our sites CLM usually overestimated gross primary production and ecosystem respiration, and underestimated net ecosystem exchange. Initial aboveground biomass in 1980 was largely overestimated for deciduous forests, whereas aboveground biomass accumulation between 1980 and 2011 was highly underestimated for both evergreen and deciduous sites due to the lower turnover rate in the sites than the one used in the model. CLM overestimated LAI in both evergreen and deciduous sites because the Leaf C-LAI relationship in the model did not match the observed Leaf C-LAI relationship in our sites. Although the different C allocation schemes gave similar results for aggregated C fluxes, they translated to important differences in long-term aboveground biomass accumulation and aboveground NPP. For deciduous forests, one of the alternative C allocation schemes used (iii) gave more realistic stem C/leaf C ratios, and highly reduced the overestimation of initial aboveground biomass, and accumulated aboveground NPP for deciduous forests by CLM. Our results would suggest using different C allocation schemes for evergreen and deciduous forests. It is crucial to improve CLM in the near future to minimize data-model mismatches, and to address some of the current model structural errors and parameter uncertainties.

Investigating impacts of economic growth on the environment using remote sensing tools: A case study of gross domestic product and net primary production in China from 2001 to 2007

NASA Astrophysics Data System (ADS)

Zhao, Naizhuo

Pursuing sustainable co-development of economy and environment has been established as a basic national policy by the present Chinese government. However, studies regarding actual outcomes of the co-development policy at the whole Chinese scale are still limited. Detecting China's economic growth and changes of environmental quality will not only contribute to evaluation of outcomes of the co-development policy but more importantly is an opportunity to examine the suitability of the IPAT model and improve our understanding of human-environment interactions. The core of the IPAT theory is an equation where I=PxAxT that models human impact on the environment as a function of changes to population (P), affluence ( A), and technology (T). The IPAT theory emphasizes that economic growth will inevitably produce negative impacts on the environment. Thus, if China's environmental quality declined while economic growth occurred, then the IPAT theory will be substantiated. Otherwise, the suitability of the IPAT theory will be called into question and its tenets must be reconsidered. In this dissertation research I selected gross domestic product (GDP) and net primary production (NPP) as indicators to evaluate production of social and ecological systems respectively. The main study objectives are (1) to develop a methodology to facilitate integration of the two indicators derived from demographic data sources and satellite imagery at different geographic scales, (2) to jointly explore changing patterns of China's economic and ecological production (i.e., spatially and temporally coincident patterns of change in GDP and NPP) across different spatial scales, (3) to analyze whether economic growth has produced negative impacts on ecosystem production and whether the impacts correlate to the economic growth, and finally (4) to discuss whether the IPAT theory is suitable for explaining the joint changes of GDP and NPP in China or if it is in need of modification. To fulfill the study objectives, nighttime light images and LandScan gridded population data were used to disaggregate demographic GDP data reported at the province level to the pixel level. The disaggregated GDP data were integrated with MODIS annual NPP data to map joint changes of GDP and NPP from 2001 to 2007. Economic development and environmental change can lead to land cover change, and the land cover change can, in turn, determine the changes of NPP. Thus, a change detection matrix with basic land cover elements was produced from MODIS land cover type products to augment the analyses of changing patterns of GDP and NPP in China. To safely discern that the changes of NPP are mainly affected by anthropogenic factors and not natural forces, the extents of undeveloped, established developed (existing before 2001), and newly developed (emerging after 2001) areas were delimited from the nighttime light images. Results show that most Chinese developed areas experienced coupled increases in GDP and NPP between 2001 and 2007 across different geographic scales, but no significant correlations exist between the total changes (or percentage changes) in GDP and NPP at the province, the city, or the pixel level. Despite large increases in GDP, the decreases in vegetated land expected according to IPAT theory did not occur in developed areas. Instead, barren land markedly decreased and built-up land slightly decreased in extent. These changing patterns suggest that China's economic growth produced some positive impacts on its ecosystem production as measured using NPP. In light of these findings a reexamination of the IPAT theory is necessary. I propose a revision to the Environmental Kuznets Curve (EKC) concept to fully illustrate the relationship between economic growth and ecosystem production as an indicator of environmental quality. According to the EKC, at relatively low levels of economic output, economic growth produces negative impacts on environmental quality. The negative impacts tend to reach a maximum at high levels of economic output and then decline at sustained levels of high economic output. My findings indicate that at sustained levels of high economic output some negative impacts may be reduced, but that some positive impacts may simultaneously emerge.

[The main radionuclides and dose formation in fish of the Chernobyl NPP exclusion zone].

PubMed

Gudkov, D I; Kaglian, A E; Kireev, S I; Nazarov, A B; Klenus, V G

2008-01-01

The results of the researches of spices-specificity, accumulation dynamics and distribution of 90Sr, of 137Cs and of transuranic elements in fish of the Chernobyl NPP exclusion zone are analysed. The data of estimations of absorbed doze rate from incorporated radionuclides for pray fish and predatory species are given. For the fish from the lake of the left-bank floodplain of the Pripyat River the increase of 90Sr specific activity is registered which is presumably connected with the dynamics of the physical-chemical forms of the radionuclide in soils and their wash out in water bodies from the catchment basin. Now about 90% of internal dose rate of fish from closed aquatic ecosystems within the Chernobyl NPP exclusion zone is caused by 90Sr incorporation.

Experimental collaboration for thick concrete structures with alkali-silica reaction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ezell, N Dianne Bull; Hayes, Nolan W.; Lenarduzzi, Roberto

Alkali-Silica Reaction (ASR) is a reaction that occurs over time in concrete between alkaline cement paste and reactive, non-crystalline silica in aggregates. An expansive gel is formed within the aggregates which results in micro-cracks in aggregates and adjacent cement paste. The reaction requires the presence of water and has been predominantly detected in groundwater-impacted portions of below grade structures, with limited impact to exterior surfaces in above grade structures. ASR can potentially affect concrete properties and performance characteristics such as compressive strength, modulus of elasticity, shear strength, and tensile strength. Since ASR degradation often takes significant amounts of time, developingmore » ASR detection techniques is important to the sustainability and extended operation lifetimes of nuclear power plants (NPPs). The University of Tennessee, Knoxville (UTK) in collaboration with Oak Ridge National Laboratory (ORNL) designed and built an experiment representative of typical NPP structures to study ASR in thick concrete structures.« less

Experimental collaboration for thick concrete structures with alkali-silica reaction

NASA Astrophysics Data System (ADS)

Ezell, N. Dianne Bull; Hayes, Nolan; Lenarduzzi, Roberto; Clayton, Dwight; Ma, Z. John; Le Pape, Sihem; Le Pape, Yann

2018-04-01

Alkali-Silica Reaction (ASR) is a reaction that occurs over time in concrete between alkaline cement paste and reactive, non-crystalline silica in aggregates. An expansive gel is formed within the aggregates which results in micro-cracks in aggregates and adjacent cement paste. The reaction requires the presence of water and has been predominantly detected in groundwater-impacted portions of below grade structures, with limited impact to exterior surfaces in above grade structures. ASR can potentially affect concrete properties and performance characteristics such as compressive strength, modulus of elasticity, shear strength, and tensile strength. Since ASR degradation often takes significant amounts of time, developing ASR detection techniques is important to the sustainability and extended operation lifetimes of nuclear power plants (NPPs). The University of Tennessee, Knoxville (UTK) in collaboration with Oak Ridge National Laboratory (ORNL) designed and built an experiment representative of typical NPP structures to study ASR in thick concrete structures.

The NPOESS Preparatory Project (NPP) Science Data Segment (SDS) Data Depository and Distribution Element (SD3E) System Architecture

NASA Technical Reports Server (NTRS)

Ho, Evelyn L.; Schweiss, Robert J.

2008-01-01

The National Polar-orbiting Operational Environmental Satellite System (NPOESS), the U.S. Government's future low-Earth orbiting satellite system, will monitor global weather and environmental conditions. Serving as a risk reduction for NPOESS, the NPOESS Preparatory Project (NPP) will provide remotely sensed atmospheric, land, ocean, ozone, and sounder data that will serve the meteorological and global climate change scientific communities. The National Aeronautics and Space Administration (NASA) NPP Science Data Segment's (SDS) primary role is to independently assess the quality of the NPP science and environmental data records for their ability to support climate research. The SDS is composed of nine elements; an input element that receives data from the operational agencies and acts as a buffer, a calibration analysis element, five elements devoted to measurement based quality assessment, an element used to test algorithmic improvements, and an element that provides overall science direction. Each element requires a set of sensor specific science data products for their evaluation. There are four NPP sensors that will be flown on the NPP observatory. They are the Visible Infrared Imagining Radiometer Suite (VIIRS), the Advanced Technology Microwave Sounder (ATMS), the Cross-Track Infrared Sounder (CrIS), and the Ozone Mapper/Profiler Suite (OMPS). It is estimated that these four sensors combined will make daily data requests for approximately six terabytes of NPP science products from the operational data providers. As a result, issues associated with duplicate data requests, data transfers of large volumes of diverse products, and data transfer failures raised concerns with respect to the network traffic and bandwidth consumption. Therefore, a central data broker system for receiving and buffering data requests and data products for the SDS was developed. The data element for this system is called the SDS Data Depository and Distribution Element (SD3E). It supports science mission data assessment by assuring the timely and validated acquisition and subsequent transfer of the NPP Science Mission data to the SDS Elements and NPP Science Team. The six science elements that interface with the SD3E span across the NASA Goddard Space Flight Center (GSFC), the NASA Jet Propulsion Laboratory (JPL), and the University of Wisconsin. As the primary communication vehicle for the science elements and science team, the SD3E has an interface to the operational data providers: National Environment Satellite, Data, and Information Service (NESDIS) Interface Data Processing System (IDPS) and the National Oceanic Atmospheric Administration's (NOAA) Comprehensive Large Array-data Stewardship system (CLASS) Archive Data System (ADS), that are responsible for product generation and archive and distribution respectively. The SD3E is designed to be a semi-customizable and semi-automated system. This system is designed to provide flexibility and ease of use for the science users in accessing the latest data products by creating a rolling data cache that temporarily stores the products locally before transferring the data to the SDS Measurement based elements for the land, ocean, atmosphere, sounder, and ozone. This paper describes the design and architecture of one of the nine SDS elements, the SD3E, and how this system has provided a mechanism for efficient data exchange, how it has helped in alleviating some of the network traffic and usage, and how it has contributed to reducing operational costs.

Direct in situ measurement of Carbon Allocation to Mycorrhizal Fungi in a California Mixed-Conifer Forest

NASA Astrophysics Data System (ADS)

Allen, M. F.

2011-12-01

Mycorrhizal fungi represent a large allocation of C to ecosystems, based on indirect measurements (tree girdling) and glasshouse extrapolations. However, we have no direct measures carbon (C) sink, in part because technologies for studying belowground dynamics on time scales at which roots and microbes grow and die have not existed. We initiated new sensor and observation platforms belowground to characterize and quantify belowground dynamics in a California mixed-conifer ecosystem. For the first time, we directly observed growth and mortality of mycorrhizal fungi in situ. We measured soil CO2, T and θ at 5-min intervals into the soil profile. Using our automated minirhizotron (AMR) for hyphal dynamics and the Bartz minirhizotron for longer-term and spatial variation in roots and rhizomorphs, we measured root, rhizomorph, hyphal growth, and belowground phenology up to 4x daily. These data are coupled with sensors measuring eddy flux of water and CO2, sapflow for water fluxes and C fixation activity, and photographs for leaf phenology. Because our data were collected at short intervals, we can describe integrative C exchange using the DayCent model for NPP and measured NPP of rhizomorphs, and fungal hyphae. Here, we focused on an arbuscular mycorrhiza dominated meadow and an ectomycorrhizal pine/oak forest at the James Reserve, in southern California. By daily measuring hyphal growth and mortality, we constructed life-span estimates of mycorrhizal hyphae, and from these, C allocation estimates. In the meadow, the NPP was 141g/m2/y, with a productivity of fine root+internal AM fungi of 76.5g C/m2/y, and an estimated 10% of which is AM fungal C allocation (7.7 g/m2/y). Extramatrical AM hyphal peak standing crop was 10g/m2, with a lifespan of 46 days (with active hyphae persisting for ~240 days per year days). Thus, the annual AM fungal allocation was 7.7g C/m2/y internal and 52g/m2/y external, for a net allocation of 84g C/m2/y, or 60% of the estimated NPP. In the forest, standing crop of root (300g C/m2/y), rhizomorph (2mg C/m2/y) was approximately 50% of the NPP. EM fungal hyphae mass was 18g/m2/y, with a 36day lifespan (persisting throughout the year), or 171 g C/m2/y. Individual EM root tips last most of the growing season at this site, as do individual rhizomorphs. Assuming that EM fungi represent 40% of the fine root EM NPP (of 200g C/m2/y) or 80g C/m2/y, most of the rhizomorph (in the mineral soil) mass being EM (or 2mg C) and 57% of the soil fungal NPP or 97 g C/m2/y, then the EM NPP is 177g C/m2/y, or 30% of the estimated NPP (600g C/m2/y). The next step is to incorporate dynamic events into the annual dynamics, providing a more detailed estimation of allocation, to determine fungal respiration and the proportion of root, mycorrhizal fungal, and saprotrophic, and to differentiate the proportion of residual organic C from hyphae in soils. With these data, we can now begin examining the impacts of changing temperature and moisture regimes on soil C dynamics.

Multiscale integral analysis of a HT leakage in a fusion nuclear power plant

NASA Astrophysics Data System (ADS)

Velarde, M.; Fradera, J.; Perlado, J. M.; Zamora, I.; Martínez-Saban, E.; Colomer, C.; Briani, P.

2016-05-01

The present work presents an example of the application of an integral methodology based on a multiscale analysis that covers the whole tritium cycle within a nuclear fusion power plant, from a micro scale, analyzing key components where tritium is leaked through permeation, to a macro scale, considering its atmospheric transport. A leakage from the Nuclear Power Plants, (NPP) primary to the secondary side of a heat exchanger (HEX) is considered for the present example. Both primary and secondary loop coolants are assumed to be He. Leakage is placed inside the HEX, leaking tritium in elementary tritium (HT) form to the secondary loop where it permeates through the piping structural material to the exterior. The Heating Ventilation and Air Conditioning (HVAC) system removes the leaked tritium towards the NPP exhaust. The HEX is modelled with system codes and coupled to Computational Fluid Dynamic (CFD) to account for tritium dispersion inside the nuclear power plants buildings and in site environment. Finally, tritium dispersion is calculated with an atmospheric transport code and a dosimetry analysis is carried out. Results show how the implemented methodology is capable of assessing the impact of tritium from the microscale to the atmospheric scale including the dosimetric aspect.

The ratio of NPP to GPP: evidence of change over the course of stand development.

PubMed

Mäkelä, A; Valentine, H T

2001-09-01

Using Scots pine (Pinus sylvestris L.) in Fenno-Scandia as a case study, we investigate whether net primary production (NPP) and maintenance respiration are constant fractions of gross primary production (GPP) as even-aged mono-specific stands progress from initiation to old age. A model of the ratio of NPP to GPP is developed based on (1) the classical model of respiration, which divides total respiration into construction and maintenance components, and (2) a process-based model, which derives respiration from processes including construction, nitrate uptake and reduction, ion uptake, phloem loading and maintenance. Published estimates of specific respiration and production rates, and some recent measurements of components of dry matter in stands of different ages, are used to quantify the two approaches over the course of stand development in an average environment. Both approaches give similar results, showing a decrease in the NPP/GPP ratio with increasing tree height. In addition, we show that stand-growth models fitted under three different sets of assumptions-(i) annual specific rates of maintenance respiration of sapwood (mW) and photosynthesis (sC) are constant; (ii) m(W) is constant, but sC decreases with increasing tree height; and (iii) total maintenance respiration is a constant fraction of GPP and s(C) decreases with increasing tree height-can lead to nearly identical model projections that agree with empirical observations of NPP and stand-growth variables. Remeasurements of GPP and respiration over time in chronosequences of stands may be needed to discern which set of assumptions is correct. Total (construction + maintenance) sapwood respiration per unit mass of sapwood (kg C (kg C year)-1) decreased with increasing stand age, sapwood stock, and average tree height under all three assumptions. However, total sapwood respiration (kg C (ha year)-1) increased over the course of stand development under (i) and (ii), contributing to a downward trend in the time course of the NPP/GPP ratio after closure. A moderate decrease in mW with increasing tree height or sapwood cross-sectional area had little effect on the downward trend. On the basis of this evidence, we argue that a significant decline in the NPP/GPP ratio with tree size or age seems highly probable, although the decline may appear insignificant over some segments of stand development. We also argue that, because stand-growth models can give correct answers for the wrong reasons, statistical calibration of such models should be avoided whenever possible; instead, values of physiological parameters should come from measurements of the physiological processes themselves.

Using VIIRS/NPP and MODIS/Aqua data to provide a continuous record of suspended particulate matter in a highly turbid inland lake

NASA Astrophysics Data System (ADS)

Cao, Zhigang; Duan, Hongtao; Shen, Ming; Ma, Ronghua; Xue, Kun; Liu, Dong; Xiao, Qitao

2018-02-01

Inland lakes are generally an important source of drinking water, and information on their water quality needs to be obtained in real time. To date, Moderate-resolution imaging spectroradiometer (MODIS) data have played a critical, effective and long-term role in fulfilling this function. However, the MODIS instruments on board both the Terra and Aqua satellites have operated beyond their designed five-year mission lifespans (Terra was launched in 1999, whereas Aqua was launched in 2002), and these instruments may stop running at any time in the near future. The Visible Infrared Imager Radiometer Suite (VIIRS) on board the Suomi National Polar-Orbiting Partnership (Suomi NPP, which was launched in Oct 2011) is expected to provide a consistent, long-term data record and continue the series of observations initiated by MODIS. To date, few evaluations of the consistency between VIIRS and MODIS have been conducted for turbid inland waters. In this study, we first used synchronous MODIS/Aqua and VIIRS/NPP data (±1 h) collected during 2012-2015 to evaluate the consistency of Rayleigh-corrected reflectance (Rrc) observations over Lake Hongze (the fourth-largest freshwater lake in China), since accurate remote sensing reflectance (Rrs) values cannot be acquired over turbid inland waters. Second, we used recently developed algorithms based on Rrc in the red band to estimate the concentrations of suspended particulate matter (SPM) from MODIS/Aqua and VIIRS/NPP data. Finally, we assessed the consistency of the SPM products derived from MODIS/Aqua and VIIRS/NPP. The results show the following. (1) The differences in Rrc among the green (VIIRS 551 nm and MODIS 555 nm) and red bands (VIIRS 671 nm and MODIS 645 nm) indicate a satisfactory consistency, and the unbiased percentage difference (UPD) is <12%. Meanwhile, the results for the near infrared (NIR) band (MODIS 859 nm and VIIRS 862 nm) indicate relatively large differences (UPD = 21.84%). (2) The satellite-derived SPM products obtained using MODIS/Aqua and VIIRS/NPP have a satisfactory degree of consistency (0-150 mg/L SPM: R2 = 0.81, UPD < 16% and 0-80 mg/L SPM: R2 = 0.85, UPD < 12%, respectively). These results demonstrate that VIIRS/NPP can continue to record the SPM observations initiated by MODIS/Aqua for turbid inland waters and establish environmental datasets over long time periods to support water quality management endeavors.

Comprehensive silicon solar-cell computer modeling

NASA Technical Reports Server (NTRS)

Lamorte, M. F.

1984-01-01

A comprehensive silicon solar cell computer modeling scheme was developed to perform the following tasks: (1) model and analysis of the net charge distribution in quasineutral regions; (2) experimentally determined temperature behavior of Spire Corp. n+pp+ solar cells where n+-emitter is formed by ion implantation of 75As or 31P; and (3) initial validation results of computer simulation program using Spire Corp. n+pp+ cells.

Studying the secondary coolant circuit rupture protection algorithm for the Novovoronezh NPP Unit 5 on a full-scale training simulator

NASA Astrophysics Data System (ADS)

Kharchenko, K. S.; Vitkovskii, I. L.

2014-02-01

Performance of the secondary coolant circuit rupture algorithm in different operating modes of the Novovoronezh NPP Unit 5 is considered by carrying out studies on a full-scale training simulator. The revealed shortcomings of the algorithm causing excessive actuations of the protection are pointed out, and recommendations for removing them are outlined.

Calculating net primary productivity of forest ecosystem with G4M model: case study on South Korea

NASA Astrophysics Data System (ADS)

Sung, S.; Forsell, N.; Kindermann, G.; Lee, D. K.

2015-12-01

Net primary productivity (NPP) is considered as an important indicator for forest ecosystem since the role of forest is highlighted as a stepping stone for mitigating climate change. Especially rapidly urbanizing countries which have high carbon dioxide emission have large interest in calculating forest NPP under climate change. Also maximizing carbon sequestration in forest sector has became a global goal to minimize the impacts of climate change. Therefore, the objective of this research is estimating carbon stock change under the different climate change scenarios by using G4M (Global Forestry Model) model in South Korea. We analyzed four climate change scenarios in different Representative Concentration Pathway (RCP). In this study we used higher resolution data (1kmx1km) to produce precise estimation on NPP from regionalized four climate change scenarios in G4M model. Finally, we set up other environmental variables for G4M such as water holding capacity, soil type and elevation. As a result of this study, temperature showed significant trend during 2011 to 2100. Average annual temperature increased more than 5℃ in RCP 8.5 scenario while 1℃ increased in RCP 2.6 scenario. Each standard deviation of the annual average temperature showed similar trend. Average annual precipitation showed similarity within four scenarios. However the standard deviation of average annual precipitation is higher in RCP8.5 scenario which indicates the ranges of precipitation is wider in RCP8.5 scenario. These results present that climate indicators such as temperature and precipitation have uncertainties in climate change scenarios. NPP has changed from 5-13tC/ha/year in RCP2.6 scenario to 9-21 tC/ha/year in RCP8.5 scenario in 2100. In addition the spatial distribution of NPP presented different trend among the scenarios. In conclusion we calculated differences in temperature and precipitation and NPP change in different climate change scenarios. This study can be applied for maximizing carbon seqestration of vegetation.

Cloud-based Web Services for Near-Real-Time Web access to NPP Satellite Imagery and other Data

NASA Astrophysics Data System (ADS)

Evans, J. D.; Valente, E. G.

2010-12-01

We are building a scalable, cloud computing-based infrastructure for Web access to near-real-time data products synthesized from the U.S. National Polar-Orbiting Environmental Satellite System (NPOESS) Preparatory Project (NPP) and other geospatial and meteorological data. Given recent and ongoing changes in the the NPP and NPOESS programs (now Joint Polar Satellite System), the need for timely delivery of NPP data is urgent. We propose an alternative to a traditional, centralized ground segment, using distributed Direct Broadcast facilities linked to industry-standard Web services by a streamlined processing chain running in a scalable cloud computing environment. Our processing chain, currently implemented on Amazon.com's Elastic Compute Cloud (EC2), retrieves raw data from NASA's Moderate Resolution Imaging Spectroradiometer (MODIS) and synthesizes data products such as Sea-Surface Temperature, Vegetation Indices, etc. The cloud computing approach lets us grow and shrink computing resources to meet large and rapid fluctuations (twice daily) in both end-user demand and data availability from polar-orbiting sensors. Early prototypes have delivered various data products to end-users with latencies between 6 and 32 minutes. We have begun to replicate machine instances in the cloud, so as to reduce latency and maintain near-real time data access regardless of increased data input rates or user demand -- all at quite moderate monthly costs. Our service-based approach (in which users invoke software processes on a Web-accessible server) facilitates access into datasets of arbitrary size and resolution, and allows users to request and receive tailored and composite (e.g., false-color multiband) products on demand. To facilitate broad impact and adoption of our technology, we have emphasized open, industry-standard software interfaces and open source software. Through our work, we envision the widespread establishment of similar, derived, or interoperable systems for processing and serving near-real-time data from NPP and other sensors. A scalable architecture based on cloud computing ensures cost-effective, real-time processing and delivery of NPP and other data. Access via standard Web services maximizes its interoperability and usefulness.

A long-term simulation of forest carbon fluxes over the Qilian Mountains

NASA Astrophysics Data System (ADS)

Yan, Min; Tian, Xin; Li, Zengyuan; Chen, Erxue; Li, Chunmei; Fan, Wenwu

2016-10-01

In this work, we integrated a remote-sensing-based (the MODIS MOD_17 Gross Primary Productivity (GPP) model (MOD_17)) and a process-based (the Biome-BioGeochemical Cycles (Biome-BGC) model) ecological model in order to estimate long-term (from 2000 to 2012) forest carbon fluxes over the Qilian Mountains in northwest China, a cold and arid forest ecosystem. Our goal was to obtain an accurate and quantitative simulation of spatial GPP patterns using the MOD_17 model and a temporal description of forest processes using the Biome-BGC model. The original MOD_17 model was first optimized using a biome-specific parameter, observed meteorological data, and reproduced fPAR at the eddy covariance site. The optimized MOD_17 model performed much better (R2 = 0.91, RMSE = 5.19 gC/m2/8d) than the original model (R2 = 0.47, RMSE = 20.27 gC/m2/8d). The Biome-BGC model was then calibrated using GPP for 30 representative forest plots selected from the optimized MOD_17 model. The calibrated Biome-BGC model was then driven in order to estimate forest GPP, net primary productivity (NPP), and net ecosystem exchange (NEE). GPP and NEE were validated against two-year (2010 and 2011) EC measurements (R2 = 0.79, RMSE = 1.15 gC/m2/d for GPP; and R2 = 0.69, RMSE = 1.087 gC/m2/d for NEE). NPP estimates from 2000 to 2012 were then compared to dendrochronological measurements (R2 = 0.73, RMSE = 24.46 gC/m2/yr). Our results indicated that integration of the two models can be used for estimating carbon fluxes with good accuracy and a high temporal and spatial resolution. Overall, NPP displayed a downward trend, with an average rate of 0.39 gC/m2/yr, from 2000 and 2012 over the Qilian Mountains. Simulated average annual NPP yielded higher values for the southeast as compared to the northwest. The most positive correlative climatic factor to average annual NPP was downward shortwave radiation. The vapor pressure deficit, and mean temperature and precipitation yielded negative correlations to average annual NPP.

Dryland ecosystem responses to precipitation extremes and wildfire at a long-term rainfall manipulation experiment

NASA Astrophysics Data System (ADS)

Brown, R. F.; Collins, S. L.

2017-12-01

Climate is becoming increasingly more variable due to global environmental change, which is evidenced by fewer, but more extreme precipitation events, changes in precipitation seasonality, and longer, higher severity droughts. These changes, combined with a rising incidence of wildfire, have the potential to strongly impact net primary production (NPP) and key biogeochemical cycles, particularly in dryland ecosystems where NPP is sequentially limited by water and nutrient availability. Here we utilize a ten-year dataset from an ongoing long-term field experiment established in 2007 in which we experimentally altered monsoon rainfall variability to examine how our manipulations, along with naturally occurring events, affect NPP and associated biogeochemical cycles in a semi-arid grassland in central New Mexico, USA. Using long-term regional averages, we identified extremely wet monsoon years (242.8 mm, 2013), and extremely dry monsoon years (86.0 mm, 2011; 80.0 mm, 2015) and water years (117.0 mm, 2011). We examined how changes in precipitation variability and extreme events affected ecosystem processes and function particularly in the context of ecosystem recovery following a 2009 wildfire. Response variables included above- and below-ground plant biomass (ANPP & BNPP) and abundance, soil nitrogen availability, and soil CO2 efflux. Mean ANPP ranged from 3.6 g m-2 in 2011 to 254.5 g m-2 in 2013, while BNPP ranged from 23.5 g m-2 in 2015 to 194.2 g m-2 in 2013, demonstrating NPP in our semi-arid grassland is directly linked to extremes in both seasonal and annual precipitation. We also show increased nitrogen deposition positively affects NPP in unburned grassland, but has no significant impact on NPP post-fire except during extremely wet monsoon years. While soil respiration rates reflect lower ANPP post-fire, patterns in CO2 efflux have not been shown to change significantly in that efflux is greatest following large precipitation events preceded by longer drying periods. Current land surface models poorly represent dryland ecosystems, which frequently undergo extreme weather events. Our long-term experiment provides key insights into ecosystem processes and function, thereby providing capacity for model improvement particularly in the context of future environmental change.

Ozone and haze pollution weakens net primary productivity in China

NASA Astrophysics Data System (ADS)

Yue, Xu; Unger, Nadine; Harper, Kandice; Xia, Xiangao; Liao, Hong; Zhu, Tong; Xiao, Jingfeng; Feng, Zhaozhong; Li, Jing

2017-05-01

Atmospheric pollutants have both beneficial and detrimental effects on carbon uptake by land ecosystems. Surface ozone (O3) damages leaf photosynthesis by oxidizing plant cells, while aerosols promote carbon uptake by increasing diffuse radiation and exert additional influences through concomitant perturbations to meteorology and hydrology. China is currently the world's largest emitter of both carbon dioxide and short-lived air pollutants. The land ecosystems of China are estimated to provide a carbon sink, but it remains unclear whether air pollution acts to inhibit or promote carbon uptake. Here, we employ Earth system modeling and multiple measurement datasets to assess the separate and combined effects of anthropogenic O3 and aerosol pollution on net primary productivity (NPP) in China. In the present day, O3 reduces annual NPP by 0.6 Pg C (14 %) with a range from 0.4 Pg C (low O3 sensitivity) to 0.8 Pg C (high O3 sensitivity). In contrast, aerosol direct effects increase NPP by 0.2 Pg C (5 %) through the combination of diffuse radiation fertilization, reduced canopy temperatures, and reduced evaporation leading to higher soil moisture. Consequently, the net effects of O3 and aerosols decrease NPP by 0.4 Pg C (9 %) with a range from 0.2 Pg C (low O3 sensitivity) to 0.6 Pg C (high O3 sensitivity). However, precipitation inhibition from combined aerosol direct and indirect effects reduces annual NPP by 0.2 Pg C (4 %), leading to a net air pollution suppression of 0.8 Pg C (16 %) with a range from 0.6 Pg C (low O3 sensitivity) to 1.0 Pg C (high O3 sensitivity). Our results reveal strong dampening effects of air pollution on the land carbon uptake in China today. Following the current legislation emission scenario, this suppression will be further increased by the year 2030, mainly due to a continuing increase in surface O3. However, the maximum technically feasible reduction scenario could drastically relieve the current level of NPP damage by 70 % in 2030, offering protection of this critical ecosystem service and the mitigation of long-term global warming.

Automated Monitoring of Carbon Fluxes in a Northern Rocky Mountain Forest Indicates Above-Average Net Primary Productivity During the 2015 Western U.S. Drought

NASA Astrophysics Data System (ADS)

Stenzel, J.; Hudiburg, T. W.

2016-12-01

As global temperatures rise in the 21st century, "hotter" droughts will become more intense and persistent, particularly in areas which already experience seasonal drought. Because forests represent a large and persistent terrestrial carbon sink which has previously offset a significant proportion of anthropogenic carbon emissions, forest carbon cycle responses to drought have become a prominent research concern. However, robust mechanistic modeling of carbon balance responses to projected drought effects requires improved observation-driven representations of carbon cycle processes; many such component processes are rarely monitored in complex terrain, are modeled or unrepresented quantities at eddy covariance sites, or are monitored at course temporal scales that are not conducive to elucidating process responses at process time scales. In the present study, we demonstrate the use of newly available and affordable automated dendrometers for the estimation of intra-seasonal Net Primary Productivity (NPP) in a Northern Rocky Mountain conifer forest which is impacted by seasonal drought. Results from our pilot study suggest that NPP was restricted by mid-summer moisture deficit under the extraordinary 2015 Western U.S. drought, with greater than 90% off stand growth occurring prior to August. Examination of growth on an inter-annual scale, however, suggests that the study site experienced above-average NPP during this exceptionally hot year. Taken together, these findings indicate that intensifying mid-summer drought in regional forests has affected the timing but has not diminished the magnitude of this carbon flux. By employing automated instrumentation for the intra-annual assessment of NPP, we reveal that annual NPP in regional forests is largely determined before mid-summer and is therefore surprisingly resilient to intensities of seasonal drought that exceed normal conditions of the 20th century.

Safety system augmentation at Russian nuclear power plants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Scerbo, J.A.; Satpute, S.N.; Donkin, J.Y.

1996-12-31

This paper describes the design and procurement of a Class IE DC power supply system to upgrade plant safety at the Kola Nuclear Power Plant (NPP). Kola NPP is located above the Arctic circle at Polyarnie Zorie, Murmansk, Russia. Kola NPP consists of four units. Units 1 and 2 have VVER-440/230 type reactors: Units 3 and 4 have VVER-440/213 type reactors. The VVER-440 reactor design is similar to the pressurized water reactor design used in the US. This project provided redundant, Class 1E DC station batteries and DC switchboards for Kola NPP, Units 1 and 2. The new DC powermore » supply system was designed and procured in compliance with current nuclear design practices and requirements. Technical issues that needed to be addressed included reconciling the requirements in both US and Russian codes and satisfying the requirements of the Russian nuclear regulatory authority. Close interface with ATOMENERGOPROEKT (AEP), the Russian design organization, KOLA NPP plant personnel, and GOSATOMNADZOR (GAN), the Russian version of US Nuclear Regulatory Commission, was necessary to develop a design that would assure compliance with current Russian design requirements. Hence, this project was expected to serve as an example for plant upgrades at other similar VVER-440 nuclear plants. In addition to technical issues, the project needed to address language barriers and the logistics of shipping equipment to a remote section of the Former Soviet Union (FSU). This project was executed by Burns and Roe under the sponsorship of the US DOE as part of the International Safety Program (INSP). The INSP is a comprehensive effort, in cooperation with partners in other countries, to improve nuclear safety worldwide. A major element within the INSP is the improvement of the safety of Soviet-designed nuclear reactors.« less

Comparison Between NPP-VIIRS Aerosol Data Products and the MODIS AQUA Deep Blue Collection 6 Dataset Over Land

NASA Technical Reports Server (NTRS)

Sayer, Andrew M.; Hsu, N. C.; Bettenhausen, C.; Lee, J.; Kondragunta, S.

2013-01-01

Aerosols are small particles suspended in the atmosphere and have a variety of natural and man-made sources. Knowledge of aerosol optical depth (AOD), which is a measure of the amount of aerosol in the atmosphere, and its change over time, is important for multiple reasons. These include climate change, air quality (pollution) monitoring, monitoring hazards such as dust storms and volcanic ash, monitoring smoke from biomass burning, determining potential energy yields from solar plants, determining visibility at sea, estimating fertilization of oceans and rainforests by transported mineral dust, understanding changes in weather brought upon by the interaction of aerosols and clouds, and more. The Suomi-NPP satellite was launched late in 2011. The Visible Infrared Imaging Radiometer Suite (VIIRS) aboard Suomi-NPP is being used, among other things, to determine AOD. This study compares the VIIRS dataset to ground-based measurements of AOD, along with a state-of-the-art satellite AOD dataset (the new version of the Moderate Resolution Imaging Spectrometer Deep Blue algorithm) to assess its reliability. The Suomi-NPP satellite was launched late in 2011, carrying several instruments designed to continue the biogeophysical data records of current and previous satellite sensors. The Visible Infrared Imaging Radiometer Suite (VIIRS) aboard Suomi-NPP is being used, among other things, to determine aerosol optical depth (AOD), and related activities since launch have been focused towards validating and understanding this new dataset through comparisons with other satellite and ground-based products. The operational VIIRS AOD product is compared over land with AOD derived from Moderate Resolution Imaging Spectrometer (MODIS) observations using the Deep Blue (DB) algorithm from the forthcoming Collection 6 of MODIS data

Progress towards the use of publicly available data networks to conduct cross-scale historical reconstructions of carbon dynamics in US Drylands

NASA Astrophysics Data System (ADS)

Washington-Allen, R. A.; Landolt, K.; Emanuel, R. E.; Therrell, M. D.; Nagle, N.; Grissino-Mayer, H. D.; Poulter, B.

2016-12-01

Emergent scale properties of water-limited or Dryland ecosystem's carbon flux are unknown at spatial scales from local to global and time scales of 10 - 1000 years or greater. The width of a tree ring is a metric of production that has been correlated with the amount of precipitation. This relationship has been used to reconstruct rainfall and fire histories in the Drylands of the southwestern US. The normalized difference vegetation index (NDVI) is globally measured by selected satellite sensors and is highly correlated with the fraction of solar radiation which is absorbed for photosynthesis by plants (FPAR), as well as with vegetation biomass, net primary productivity (NPP), and tree ring width. Publicly available web-based archives of free NDVI and tree ring data exist and have allowed historical temporal reconstructions of carbon dynamics for the past 300 to 500 years. Climate and tree ring databases have been used to spatially reconstruct drought dynamics for the last 500 years in the western US. In 2007, we hypothesized that NDVI and tree ring width could be used to spatially reconstruct carbon dynamics in US Drylands. In 2015, we succeeded with a 300-year historical spatial reconstruction of NPP in California using a Blue Oak tree ring chronology. Online eddy covariance flux tower measures of NPP are well correlated with satellite measures of NPP. This suggests that net ecosystem exchange (NEE = NPP - soil Respiration) could be historically reconstructed across Drylands. Ongoing research includes 1) scaling historical spatial reconstruction to US Drylands, 2) comparing the use of single versus multiple tree ring species (r2 = 68) and 3) use of the eddy flux tower network, remote sensing, and tree ring data to historically spatially reconstruct Dryland NEE.

Using simple environmental variables to estimate below-ground productivity in grasslands

USGS Publications Warehouse

Gill, R.A.; Kelly, R.H.; Parton, W.J.; Day, K.A.; Jackson, R.B.; Morgan, J.A.; Scurlock, J.M.O.; Tieszen, L.L.; Castle, J.V.; Ojima, D.S.; Zhang, X.S.

2002-01-01

In many temperate and annual grasslands, above-ground net primary productivity (NPP) can be estimated by measuring peak above-ground biomass. Estimates of below-ground net primary productivity and, consequently, total net primary productivity, are more difficult. We addressed one of the three main objectives of the Global Primary Productivity Data Initiative for grassland systems to develop simple models or algorithms to estimate missing components of total system NPP. Any estimate of below-ground NPP (BNPP) requires an accounting of total root biomass, the percentage of living biomass and annual turnover of live roots. We derived a relationship using above-ground peak biomass and mean annual temperature as predictors of below-ground biomass (r2 = 0.54; P = 0.01). The percentage of live material was 0.6, based on published values. We used three different functions to describe root turnover: constant, a direct function of above-ground biomass, or as a positive exponential relationship with mean annual temperature. We tested the various models against a large database of global grassland NPP and the constant turnover and direct function models were approximately equally descriptive (r2 = 0.31 and 0.37), while the exponential function had a stronger correlation with the measured values (r2 = 0.40) and had a better fit than the other two models at the productive end of the BNPP gradient. When applied to extensive data we assembled from two grassland sites with reliable estimates of total NPP, the direct function was most effective, especially at lower productivity sites. We provide some caveats for its use in systems that lie at the extremes of the grassland gradient and stress that there are large uncertainties associated with measured and modelled estimates of BNPP.

Divergent predictions of carbon storage between two global land models: attribution of the causes through traceability analysis

NASA Astrophysics Data System (ADS)

Rafique, Rashid; Xia, Jianyang; Hararuk, Oleksandra; Asrar, Ghassem R.; Leng, Guoyong; Wang, Yingping; Luo, Yiqi

2016-07-01

Representations of the terrestrial carbon cycle in land models are becoming increasingly complex. It is crucial to develop approaches for critical assessment of the complex model properties in order to understand key factors contributing to models' performance. In this study, we applied a traceability analysis which decomposes carbon cycle models into traceable components, for two global land models (CABLE and CLM-CASA') to diagnose the causes of their differences in simulating ecosystem carbon storage capacity. Driven with similar forcing data, CLM-CASA' predicted ˜ 31 % larger carbon storage capacity than CABLE. Since ecosystem carbon storage capacity is a product of net primary productivity (NPP) and ecosystem residence time (τE), the predicted difference in the storage capacity between the two models results from differences in either NPP or τE or both. Our analysis showed that CLM-CASA' simulated 37 % higher NPP than CABLE. On the other hand, τE, which was a function of the baseline carbon residence time (τ'E) and environmental effect on carbon residence time, was on average 11 years longer in CABLE than CLM-CASA'. This difference in τE was mainly caused by longer τ'E of woody biomass (23 vs. 14 years in CLM-CASA'), and higher proportion of NPP allocated to woody biomass (23 vs. 16 %). Differences in environmental effects on carbon residence times had smaller influences on differences in ecosystem carbon storage capacities compared to differences in NPP and τ'E. Overall, the traceability analysis showed that the major causes of different carbon storage estimations were found to be parameters setting related to carbon input and baseline carbon residence times between two models.

Hurricane Sandy Viewed in the Dark of Night

NASA Image and Video Library

2017-12-08

NASA image acquired October 28, 2012 For the latest info from NASA on Hurricane Sandy go to: 1.usa.gov/Ti5SgS This image of Hurricane Sandy was acquired by the Visible Infrared Imaging Radiometer Suite (VIIRS) on the Suomi NPP satellite around 2:42 a.m. Eastern Daylight Time (06:42 Universal Time) on October 28, 2012. The storm was captured by a special “day-night band,” which detects light in a range of wavelengths from green to near-infrared and uses filtering techniques to observe dim signals such as auroras, airglow, gas flares, city lights, and reflected moonlight. In this case, the cloud tops were lit by the nearly full Moon (full occurs on October 29). Some city lights in Florida and Georgia are also visible amidst the clouds. The Suomi NPP satellite was launched one year ago today (on October 28, 2011) to extend and enhance long-term records of key environmental data monitored by NASA, the National Oceanic and Atmospheric Administration (NOAA), and the U.S. Department of Defense. NASA Earth Observatory image by Jesse Allen and Robert Simmon, using VIIRS Day-Night Band data from the Suomi National Polar-orbiting Partnership (Suomi NPP). Suomi NPP is the result of a partnership between NASA, the National Oceanic and Atmospheric Administration, and the Department of Defense. Caption by Michael Carlowicz. Instrument: Suomi NPP - VIIRS NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

Vegetation Health and Productivity Indicators for Sustained National Climate Assessments

NASA Astrophysics Data System (ADS)

Jones, M. O.; Running, S. W.

2014-12-01

The National Climate Assessment process is developing a system of physical, ecological, and societal indicators that communicate key aspects of the physical climate, climate impacts, vulnerabilities, and preparedness for the purpose of informing both decision makers and the public. Implementing a 14 year record of Gross and Net Primary Productivity (GPP/NPP) derived from the NASA EOS MODIS satellite sensor we demonstrate how these products can serve as Ecosystem Productivity and Vegetation Health National Climate Indicators for implementation in sustained National Climate Assessments. The NPP product combines MODIS vegetation data with daily global meteorology to calculate annual growth of all plant material at 1 sq. km resolution. NPP anomalies identify regions with above or below average plant growth that may result from climate fluctuations and can inform carbon source/sink dynamics, agricultural and forestry yield measures, and response to wildfire or drought conditions. The GPP product provides a high temporal resolution (8-day) metric of vegetation growth which can be used to monitor short-term vegetation response to extreme events and implemented to derive vegetation phenology metrics; growing season start, end, and length, which can elucidate land cover and regionally specific vegetation responses to a changing climate. The high spatial resolution GPP and NPP indicators can also inform and clarify responses seen from other proposed Pilot Indicators such as forest growth/productivity, land cover, crop production, and phenology. The GPP and NPP data are in continuous production and will be sustained into the future with the next generation satellite missions. The long-term Ecosystem Productivity and Vegetation Health Indicators are ideal for use in sustained National Climate Assessments, providing regionally specific responses to a changing climate and complete coverage at the national scale.

Divergent predictions of carbon storage between two global land models: Attribution of the causes through traceability analysis

DOE PAGES

Rafique, Rashid; Xia, Jianyang; Hararuk, Oleksandra; ...

2016-07-29

Representations of the terrestrial carbon cycle in land models are becoming increasingly complex. It is crucial to develop approaches for critical assessment of the complex model properties in order to understand key factors contributing to models' performance. In this study, we applied a traceability analysis which decomposes carbon cycle models into traceable components, for two global land models (CABLE and CLM-CASA') to diagnose the causes of their differences in simulating ecosystem carbon storage capacity. Driven with similar forcing data, CLM-CASA' predicted – 31 % larger carbon storage capacity than CABLE. Since ecosystem carbon storage capacity is a product of net primary productivitymore » (NPP) and ecosystem residence time ( τ E), the predicted difference in the storage capacity between the two models results from differences in either NPP or τ E or both. Our analysis showed that CLM-CASA'simulated 37 % higher NPP than CABLE. On the other hand, τ E, which was a function of the baseline carbon residence time ( τ' E) and environmental effect on carbon residence time, was on average 11 years longer in CABLE than CLM-CASA'. This difference in τ E was mainly caused by longer τ' E of woody biomass (23 vs. 14 years in CLM-CASA'), and higher proportion of NPP allocated to woody biomass (23 vs. 16 %). Differences in environmental effects on carbon residence times had smaller influences on differences in ecosystem carbon storage capacities compared to differences in NPP and τ' E. Altogether, the traceability analysis showed that the major causes of different carbon storage estimations were found to be parameters setting related to carbon input and baseline carbon residence times between two models.« less

Divergent predictions of carbon storage between two global land models: Attribution of the causes through traceability analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rafique, Rashid; Xia, Jianyang; Hararuk, Oleksandra

Representations of the terrestrial carbon cycle in land models are becoming increasingly complex. It is crucial to develop approaches for critical assessment of the complex model properties in order to understand key factors contributing to models' performance. In this study, we applied a traceability analysis which decomposes carbon cycle models into traceable components, for two global land models (CABLE and CLM-CASA') to diagnose the causes of their differences in simulating ecosystem carbon storage capacity. Driven with similar forcing data, CLM-CASA' predicted – 31 % larger carbon storage capacity than CABLE. Since ecosystem carbon storage capacity is a product of net primary productivitymore » (NPP) and ecosystem residence time ( τ E), the predicted difference in the storage capacity between the two models results from differences in either NPP or τ E or both. Our analysis showed that CLM-CASA'simulated 37 % higher NPP than CABLE. On the other hand, τ E, which was a function of the baseline carbon residence time ( τ' E) and environmental effect on carbon residence time, was on average 11 years longer in CABLE than CLM-CASA'. This difference in τ E was mainly caused by longer τ' E of woody biomass (23 vs. 14 years in CLM-CASA'), and higher proportion of NPP allocated to woody biomass (23 vs. 16 %). Differences in environmental effects on carbon residence times had smaller influences on differences in ecosystem carbon storage capacities compared to differences in NPP and τ' E. Altogether, the traceability analysis showed that the major causes of different carbon storage estimations were found to be parameters setting related to carbon input and baseline carbon residence times between two models.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wilcox, Kevin R.; Shi, Zheng; Gherardi, Laureano A.

Climatic changes are altering Earth's hydrological cycle, resulting in altered precipitation amounts, increased interannual variability of precipitation, and more frequent extreme precipitation events. These trends will likely continue into the future, having substantial impacts on net primary productivity (NPP) and associated ecosystem services such as food production and carbon sequestration. Frequently, experimental manipulations of precipitation have linked altered precipitation regimes to changes in NPP. Yet, findings have been diverse and substantial uncertainty still surrounds generalities describing patterns of ecosystem sensitivity to altered precipitation. Additionally, we do not know whether previously observed correlations between NPP and precipitation remain accurate when precipitationmore » changes become extreme. We synthesized results from 83 case studies of experimental precipitation manipulations in grasslands worldwide. Here, we used meta-analytical techniques to search for generalities and asymmetries of aboveground NPP (ANPP) and belowground NPP (BNPP) responses to both the direction and magnitude of precipitation change. Sensitivity (i.e., productivity response standardized by the amount of precipitation change) of BNPP was similar under precipitation additions and reductions, but ANPP was more sensitive to precipitation additions than reductions; this was especially evident in drier ecosystems. Additionally, overall relationships between the magnitude of productivity responses and the magnitude of precipitation change were saturating in form. The saturating form of this relationship was likely driven by ANPP responses to very extreme precipitation increases, although there were limited studies imposing extreme precipitation change, and there was considerable variation among experiments. Finally, this highlights the importance of incorporating gradients of manipulations, ranging from extreme drought to extreme precipitation increases into future climate change experiments. Additionally, policy and land management decisions related to global change scenarios should consider how ANPP and BNPP responses may differ, and that ecosystem responses to extreme events might not be predicted from relationships found under moderate environmental changes.« less

Electro-optic studies of novel organic materials and devices

NASA Astrophysics Data System (ADS)

Xu, Jianjun

1997-11-01

Specific single crystal organic materials have high potential for use in high speed optical signal processing and various other electro-optic applications. In this project some of the most important organic crystal materials were studied regarding their detailed electro- optic properties and potential device applications. In particular, the electro-optic properties of N-(4- Nitrophenyl)-L-Prolinol (NPP) and 4'-N,N- dimethylamino-4-methylstilbazolium tosylate (DAST) both of which have extremely large second order susceptibilites were studied. The orientation of the thin film crystal with respect to the substrate surface was determined using-X-ray diffraction. The principal axes of the single crystal thin film were determined by polarization transmission microscopy. The elements of the electro-optic coefficient tensor were measured by field induced birefringence measurements. Detailed measurements for NPP thin films with different orientations of the external electric field with respect to the charge transfer axis were carried out at a wavelength of 1064nm. The wavelength dependence of the electro-optic effect for DAST single crystal thin films was measured using a Ti:Sapphire laser. Several device geometries involving organic single crystal thin film materials were studied. A new method for the fabrication of channel waveguides for organic materials was initiated. Channel waveguides for NPP and ABP were obtained using this methods. Optical modulation due to the electro-optic effect based on the organic channel waveguide for NPP single crystal was demonstrated. The electro-optic modulation using NPP single crystals thin film in a Fabry-Perot cavity was measured. A device using a optical fiber half coupler and organic electro-optic thin film material was constructed, and it has potential applications in optical signal processing.

Satellite infrared imagery for thermal plume contamination monitoring in coastal ecosystem of Cernavoda NPP

NASA Astrophysics Data System (ADS)

Zoran, M. A.; Zoran, Liviu Florin V.; Dida, Adrian I.

2017-10-01

Satellite remote sensing is an important tool for spatio-temporal analysis and surveillance of NPP environment, thermal heat waste of waters being a major concern in many coastal ecosystems involving nuclear power plants. As a test case the adopted methodology was applied for 700x2 MW Cernavoda nuclear power plant (NPP) located in the South-Eastern part of Romania, which discharges warm water affecting coastal ecology. The thermal plume signatures in the NPP hydrological system have been investigated based on TIR (Thermal Infrared) spectral bands of NOAA AVHRR, Landsat TM/ETM+/OLI, and MODIS Terra/Aqua time series satellite data during 1990-2016 period. If NOAA AVHRR data proved the general pattern and extension of the thermal plume signature in Danube river and Black Sea coastal areas, Landsat TM/ETM and MODIS data used for WST (Water Surface Temperature) change detection, mapping and monitoring provided enhanced information about the plume shape, dimension and direction of dispersion in these waters. Thermal discharge from two nuclear reactors cooling is dissipated as waste heat in Danube-Black -Sea Channel and Danube River. From time-series analysis of satellite data during period 1990-2016 was found that during the winter season thermal plume was localized to an area of a few km of NPP, and the mean temperature difference between the plume and non-plume areas was about 1.7 oC. During summer and fall, derived mean temperature difference between the plume and non-plume areas was of about 1.3°C and thermal plume area was extended up to 5- 10 km far along Danube Black Sea Channel.

A multi-scale assessment of forest primary production across the eastern USA using Forest Inventory and Analysis (FIA) and MODIS data

NASA Astrophysics Data System (ADS)

Kwon, Youngsang

As evidence of global warming continues to increase, being able to predict the relationship between forest growth rate and climate factors will be vital to maintain the sustainability and productivity of forests. Comprehensive analyses of forest primary production across the eastern US were conducted using remotely sensed MODIS and field-based FIA datasets. This dissertation primarily explored spatial patterns of gross and net carbon uptake in the eastern USA, and addressed three objectives. 1) Examine the use of pixel- and plot-scale screening variables to validate MODIS GPP predictions with Forest Inventory and Analysis (FIA) NPP measures. 2) Assess the net primary production (NPP) from MODIS and FIA at increasing levels of spatial aggregation using a hexagonal tiling system. 3) Assess the carbon use efficiency (CUE) calculated using a direct ratio of MODIS NPP to MODIS GPP and a standardized ratio of FIA NPP to MODIS GPP. The first objective was analyzed using total of 54,969 MODIS pixels and co-located FIA plots to validate MODIS GPP estimates. Eight SVs were used to test six hypotheses about the conditions under which MODIS GPP would be most strongly validated. SVs were assessed in terms of the tradeoff between improved relations and reduced number of samples. MODIS seasonal variation and FIA tree density were the two most efficient SVs followed by basic quality checks for each data set. The sequential application of SVs provided an efficient dataset of 17,090 co-located MODIS pixels and FIA plots, that raised the Pearson's correlation coefficient from 0.01 for the complete dataset of 54,969 plots to 0.48 for this screened subset of 17,090 plots. The second objective was addressed by aggregating data over increasing spatial extents so as to not lose plot- and pixel-level information. These data were then analyzed to determine the optimal scale with which to represent the spatial pattern of NPP. The results suggested an optimal scale of 390 km2. At that scale MODIS and FIA were most strongly correlated while maximizing the number of observation. The maps conveyed both local-scale spatial structure from FIA and broad-scale climatic trends from MODIS. The third objective examined whether carbon use efficiency (CUE) was constant or variable in relation to forest types, and to geographic and climatic variables. The results indicated that while CUEs exhibited unclear patterns by forest types, CUEs are variable to other environmental variables. CUEs are most strongly related to the climatic factors of precipitation followed by temperature. More complex and weaker relationships were found for the geographic factors of latitude and altitude, as they reflected a combination of phenomenological driving forces. The results of the three objectives will help us to identify factors that control carbon cycles and to quantify forest productivity. This will help improve our knowledge about how forest primary productivity may change in relation to ongoing climate change.

Near Real Time Processing Chain for Suomi NPP Satellite Data

NASA Astrophysics Data System (ADS)

Monsorno, Roberto; Cuozzo, Giovanni; Costa, Armin; Mateescu, Gabriel; Ventura, Bartolomeo; Zebisch, Marc

2014-05-01

Since 2009, the EURAC satellite receiving station, located at Corno del Renon, in a free obstacle site at 2260 m a.s.l., has been acquiring data from Aqua and Terra NASA satellites equipped with Moderate Resolution Imaging Spectroradiometer (MODIS) sensors. The experience gained with this local ground segmenthas given the opportunity of adapting and modifying the processing chain for MODIS data to the Suomi NPP, the natural successor to Terra and Aqua satellites. The processing chain, initially implemented by mean of a proprietary system supplied by Seaspace and Advanced Computer System, was further developed by EURAC's Institute for Applied Remote Sensing engineers. Several algorithms have been developed using MODIS and Visible Infrared Imaging Radiometer Suite (VIIRS) data to produce Snow Cover, Particulate Matter estimation and Meteo maps. These products are implemented on a common processor structure based on the use of configuration files and a generic processor. Data and products have then automatically delivered to the customers such as the Autonomous Province of Bolzano-Civil Protection office. For the processing phase we defined two goals: i) the adaptation and implementation of the products already available for MODIS (and possibly new ones) to VIIRS, that is one of the sensors onboard Suomi NPP; ii) the use of an open source processing chain in order to process NPP data in Near Real Time, exploiting the knowledge we acquired on parallel computing. In order to achieve the second goal, the S-NPP data received and ingested are sent as input to RT-STPS (Real-time Software Telemetry Processing System) software developed by the NASA Direct Readout Laboratory 1 (DRL) that gives as output RDR files (Raw Data Record) for VIIRS, ATMS (Advanced Technology Micorwave Sounder) and CrIS (Cross-track Infrared Sounder)sensors. RDR are then transferred to a server equipped with CSPP2 (Community Satellite Processing Package) software developed by the University of Wisconsin. CSPP subdivides the input file in granules, making possible the use of parallel computing, and produces SDR (Science Data Record) and some EDR (Environmental Data Record) products. The integration with the EDRs not yet available with CSPP is realized with the use of SPAs (Science Processing Algorithm) stand-alone version by DRL. The important result of this system consists in the possibility of processing data acquired by the EURAC antenna with open source software and delivering the SDRs, EDRs and higher level products developed internally by EURAC in near real time using a Data Exchange Server. By means of the parallelized CSPP, SDR data are currently available after about 7 minutes since the production of RDR, while we are currently implementing a strategy to get the best possible processing time for the EDRs products that are in principle not parallelizable. 1. http://directreadout.sci.gsfc.nasa.gov/ 2. http://cimss.ssec.wisc.edu/cspp/

Determination of the ¹⁴C content in activated steel components from a neutron spallation source and a nuclear power plant.

PubMed

Schumann, Dorothea; Stowasser, Tanja; Volmert, Benjamin; Günther-Leopold, Ines; Linder, Hanspeter; Wieland, Erich

2014-06-03

The (14)C content in activated steel components from the Swiss Nuclear Power Plant (NPP) Gösgen and the Spallation Neutron Source SINQ at the Paul Scherrer Institute is determined using a wet chemistry digestion technique and liquid scintillation counting for (14)C activity measurements. The (14)C activity of an activated fuel assembly steel nut from the NPP is further compared with theoretical predictions made on the basis of a Monte Carlo reactor model for this NPP. Knowledge of the (14)C inventory in these activated steel materials is important in conjunction with future corrosion studies on these materials aimed at identifying the (14)C containing organic compounds possibly formed in the cement-based near field of a repository for radioactive waste.

Effects of climate and lifeform on dry matter yield (epsilon) from simulations using BIOME BGC. [ecosystem process model for vegetation biomass production using daily absorbed photosynthetically active radiation

NASA Technical Reports Server (NTRS)

Hunt, E. R., Jr.; Running, Steven W.

1992-01-01

An ecosystem process simulation model, BIOME-BGC, is used in a sensitivity analysis to determine the factors that may cause the dry matter yield (epsilon) and annual net primary production to vary for different ecosystems. At continental scales, epsilon is strongly correlated with annual precipitation. At a single location, year-to-year variation in net primary production (NPP) and epsilon is correlated with either annual precipitation or minimum air temperatures. Simulations indicate that forests have lower epsilon than grasslands. The most sensitive parameter affecting forest epsilon is the total amount of living woody biomass, which affects NPP by increasing carbon loss by maintenance respiration. A global map of woody biomass should significantly improve estimates of global NPP using remote sensing.

GRIZZLY Model of Multi-Reactive Species Diffusion, Moisture/Heat Transfer and Alkali-Silica Reaction for Simulating Concrete Aging and Degradation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huang, Hai; Spencer, Benjamin W.; Cai, Guowei

Concrete is widely used in the construction of nuclear facilities because of its structural strength and its ability to shield radiation. The use of concrete in nuclear power plants for containment and shielding of radiation and radioactive materials has made its performance crucial for the safe operation of the facility. As such, when life extension is considered for nuclear power plants, it is critical to have accurate and reliable predictive tools to address concerns related to various aging processes of concrete structures and the capacity of structures subjected to age-related degradation. The goal of this report is to document themore » progress of the development and implementation of a fully coupled thermo-hydro-mechanical-chemical model in GRIZZLY code with the ultimate goal to reliably simulate and predict long-term performance and response of aged NPP concrete structures subjected to a number of aging mechanisms including external chemical attacks and volume-changing chemical reactions within concrete structures induced by alkali-silica reactions and long-term exposure to irradiation. Based on a number of survey reports of concrete aging mechanisms relevant to nuclear power plants and recommendations from researchers in concrete community, we’ve implemented three modules during FY15 in GRIZZLY code, (1) multi-species reactive diffusion model within cement materials; (2) coupled moisture and heat transfer model in concrete; and (3) anisotropic, stress-dependent, alkali-silica reaction induced swelling model. The multi-species reactive diffusion model was implemented with the objective to model aging of concrete structures subjected to aggressive external chemical attacks (e.g., chloride attack, sulfate attack, etc.). It considers multiple processes relevant to external chemical attacks such as diffusion of ions in aqueous phase within pore spaces, equilibrium chemical speciation reactions and kinetic mineral dissolution/precipitation. The moisture/heat transfer module was implemented to simulate long-term spatial and temporal evolutions of the moisture and temperature fields within concrete structures at both room and elevated temperatures. The ASR swelling model implemented in GRIZZLY code can simulate anisotropic expansions of ASR gel under either uniaxial, biaxial and triaxial stress states, and can be run simultaneously with the moisture/heat transfer model and coupled with various elastic/inelastic solid mechanics models that were implemented in GRIZZLY code previously. This report provides detailed descriptions of the governing equations, constitutive equations and numerical algorithms of the three modules implemented in GRIZZLY during FY15, simulation results of example problems and model validation results by comparing simulations with available experimental data reported in the literature. The close match between the experiments and simulations clearly demonstrate the potential of GRIZZLY code for reliable evaluation and prediction of long-term performance and response of aged concrete structures in nuclear power plants.« less

Assimilation of all-weather GMI and ATMS observations into HWRF

NASA Astrophysics Data System (ADS)

Moradi, I.; Evans, F.; McCarty, W.; Marks, F.; Eriksson, P.

2017-12-01

We propose a novel Bayesian Monte Carlo Integration (BMCI) technique to retrieve the profiles of temperature, water vapor, and cloud liquid/ice water content from microwave cloudy measurements in the presence of TCs. These retrievals then can either be directly used by meteorologists to analyze the structure of TCs or be assimilated to provide accurate initial conditions for the NWP models. The technique is applied to the data from the Advanced Technology Microwave Sounder (ATMS) onboard Suomi National Polar-orbiting Partnership (NPP) and Global Precipitation Measurement (GPM) Microwave Imager (GMI).

Net primary production and canopy nitrogen in a temperate forest landscape: an analysis using imaging spectroscopy, modeling and field data

Treesearch

Scott V. Ollinger; Marie-Louise Smith

2005-01-01

Understanding spatial patterns of net primary production (NPP) is central to the study of terrestrial ecosystems, but efforts are frequently hampered by a lack of spatial information regarding factors such as nitrogen availability and site history. Here, we examined the degree to which canopy nitrogen can serve as an indicator of patterns of NPP at the Bartlett...

Revegetation in China’s Loess Plateau is approaching sustainable water resource limits

NASA Astrophysics Data System (ADS)

Feng, Xiaoming; Fu, Bojie; Piao, Shilong; Wang, Shuai; Ciais, Philippe; Zeng, Zhenzhong; Lü, Yihe; Zeng, Yuan; Li, Yue; Jiang, Xiaohui; Wu, Bingfang

2016-11-01

Revegetation of degraded ecosystems provides opportunities for carbon sequestration and bioenergy production. However, vegetation expansion in water-limited areas creates potentially conflicting demands for water between the ecosystem and humans. Current understanding of these competing demands is still limited. Here, we study the semi-arid Loess Plateau in China, where the `Grain to Green’ large-scale revegetation programme has been in operation since 1999. As expected, we found that the new planting has caused both net primary productivity (NPP) and evapotranspiration (ET) to increase. Also the increase of ET has induced a significant (p < 0.001) decrease in the ratio of river runoff to annual precipitation across hydrological catchments. From currently revegetated areas and human water demand, we estimate a threshold of NPP of 400 +/- 5 g C m-2 yr-1 above which the population will suffer water shortages. NPP in this region is found to be already close to this limit. The threshold of NPP could change by -36% in the worst case of climate drying and high human withdrawals, to +43% in the best case. Our results develop a new conceptual framework to determine the critical carbon sequestration that is sustainable in terms of both ecological and socio-economic resource demands in a coupled anthropogenic-biological system.

Assessment of ecosystem productivity damage due to land use.

PubMed

Kaenchan, Piyanon; Guinée, Jeroen; Gheewala, Shabbir H

2018-04-15

Land use can affect ecosystems on land and their services. Because land use has mainly local effects, damage to ecosystem productivity due to land use should be modelled spatially dependent. Unfortunately, even though land use of impacts are particular importance for countries whose economies are highly agriculture-based, ecosystem productivity damage due to land use has not yet been assessed in Thailand so far. This study presents the method for assessing the damage to ecosystem productivity due to land use (land occupation and land transformation) in Thailand. Ecosystem productivity damage is expressed through net primary production (NPP). To convert the damage into monetary units, this study performs an economic valuation of NPP using the production function approach. The results show that the value of marginal product of NPP is around 10-15 Thai baht (THB) (1 USD≈36 THB), per tonne dry weight biomass. The results are applied to the case of biodiesel production. The method presented in this paper could be a guideline for future land use impact assessment research. In addition, converting the NPP damage results into monetary units facilitates integration of impact assessment and economic analysis results for supporting decision support tools such as cost benefit analysis. Copyright © 2017 Elsevier B.V. All rights reserved.

Primary Productivity in Meduxnekeag River, Maine, 2005

USGS Publications Warehouse

Goldstein, Robert M.; Schalk, Charles W.; Kempf, Joshua P.

2009-01-01

During August and September 2005, dissolved oxygen, temperature, pH, specific conductance, streamflow, and light intensity (LI) were determined continuously at six sites defining five reaches on Meduxnekeag River above and below Houlton, Maine. These data were collected as input for a dual-station whole-stream metabolism model to evaluate primary productivity in the river above and below Houlton. The river receives nutrients and organic matter from tributaries and the Houlton wastewater treatment plant (WWTP). Model output estimated gross and net primary productivity for each reach. Gross primary productivity (GPP) varied in each reach but was similar and positive among the reaches. GPP was correlated to LI in the four reaches above the WWTP but not in the reach below. Net primary productivity (NPP) decreased in each successive downstream reach and was negative in the lowest two reaches. NPP was weakly related to LI in the upper two reaches and either not correlated or negatively correlated in the lower three reaches. Relations among GPP, NPP, and LI indicate that the system is heterotrophic in the downstream reaches. The almost linear decrease in NPP (the increase in metabolism and respiration) indicates a cumulative effect of inputs of nutrients and organic matter from tributaries that drain agricultural land, the town of Houlton, and the discharges from the WWTP.

Training for vigilance: using predictive power to evaluate feedback effectiveness.

PubMed

Szalma, James L; Hancock, Peter A; Warm, Joel S; Dember, William N; Parsons, Kelley S

2006-01-01

We examined the effects of knowledge of results (KR) on vigilance accuracy and report the first use of positive and negative predictive power (PPP and NPP) to assess vigilance training effectiveness. Training individuals to detect infrequent signals among a plethora of nonsignals is critical to success in many failure-intolerant monitoring technologies. KR has been widely used for vigilance training, but the effect of the schedule of KR presentation on accuracy has been neglected. Previous research on training for vigilance has used signal detection metrics or hits and false alarms. In this study diagnosticity measures were applied to augment traditional analytic methods. We examined the effects of continuous KR and a partial-KR regimen versus a no-KR control on decision diagnosticity. Signal detection theory (SDT) analysis indicated that KR induced conservatism in responding but did not enhance sensitivity. However, KR in both forms equally enhanced PPP while selectively impairing NPP. There is a trade-off in the effectiveness of KR in reducing false alarms and misses. Together, SDT and PPP/NPP measures provide a more complete portrait of performance effects. PPP and NPP together provide another assessment technique for vigilance performance, and as additional diagnostic tools, these measures are potentially useful to the human factors community.

Spatially simulating changes of soil water content and their effects on carbon sequestration in Canada's forests and wetlands

NASA Astrophysics Data System (ADS)

Ju, Weimin; Chen, Jing M.; Black, T. Andrew; Barr, Alan G.; McCaughey, Harry

2010-07-01

The variations of soil water content (SWC) and its influences on the carbon (C) cycle in Canada's forests and wetlands were studied through model simulations using the Integrated Terrestrial Ecosystem Carbon (InTEC) model. It shows that Canada's forests and wetlands experienced spatially and temporally heterogeneous changes in SWC from 1901 to 2000. SWC changes caused average NPP to decrease 40.8 Tg C yr-1 from 1901 to 2000, whereas the integrated effect of non-disturbance factors (climate change, CO2 fertilization and N deposition) enhanced NPP by 9.9%. During 1981-2000, the reduction of NPP caused by changes in SWC was 58.1 Tg C yr-1 whereas non-disturbance factors together caused NPP to increase by 16.6%. SWC changes resulted in an average increase of 4.1 Tg C yr-1 in the net C uptake during 1901-2000, relatively small compared with the enhancement in C uptake of 50.2 Tg C yr-1 by the integrated effect of non-disturbance factors. During 1981-2000, changes in SWC caused a reduction of 3.8 Tg C yr-1 in net C sequestration whereas the integrated factors increased net C sequestration by 54.1 Tg C yr-1. Increase in SWC enhanced C sequestration in all ecozones.

Key Features of the Deployed NPP/NPOESS Ground System

NASA Astrophysics Data System (ADS)

Heckmann, G.; Grant, K. D.; Mulligan, J. E.

2010-12-01

The National Oceanic & Atmospheric Administration (NOAA), Department of Defense (DoD), and National Aeronautics & Space Administration (NASA) are jointly acquiring the next-generation weather/environmental satellite system; the National Polar-orbiting Operational Environmental Satellite System (NPOESS). NPOESS replaces the current NOAA Polar-orbiting Operational Environmental Satellites (POES) and DoD Defense Meteorological Satellite Program (DMSP). NPOESS satellites carry sensors to collect meteorological, oceanographic, climatological, and solar-geophysical data of the earth, atmosphere, and space. The ground data processing segment is the Interface Data Processing Segment (IDPS), developed by Raytheon Intelligence & Information Systems (IIS). The IDPS processes NPOESS Preparatory Project (NPP)/NPOESS satellite data to provide environmental data products/records (EDRs) to NOAA and DoD processing centers operated by the US government. The IDPS will process EDRs beginning with NPP and continuing through the lifetime of the NPOESS system. The command & telemetry segment is the Command, Control & Communications Segment (C3S), also developed by Raytheon IIS. C3S is responsible for managing the overall NPP/NPOESS missions from control & status of the space and ground assets to ensuring delivery of timely, high quality data from the Space Segment to IDPS for processing. In addition, the C3S provides the globally-distributed ground assets needed to collect and transport mission, telemetry, and command data between the satellites and processing locations. The C3S provides all functions required for day-to-day satellite commanding & state-of-health monitoring, and delivery of Stored Mission Data to each Central IDP for data products development and transfer to system subscribers. The C3S also monitors and reports system-wide health & status and data communications with external systems and between the segments. The C3S & IDPS segments were delivered & transitioned to operations for NPP. C3S transitioned to operations at the NOAA Satellite Operations Facility (NSOF) in Suitland Maryland in August 2007 and IDPS transitioned in July 2009. Both segments were involved with several compatibility tests with the NPP Satellite at the Ball Aerospace Technology Corporation (BATC) factory. The compatibility tests involved the spacecraft bus, the four sensors (VIIRS, ATMS, CrIS and OMPS), and both ground segments flowing data between the NSOF and BATC factory and flowing data from the polar ground station (Svalbard) over high-speed links back to the NSOF and the two IDP locations (NESDIS & AFWA). This presentation will describe the NPP/NPOESS ground architecture features & enhancements for the NPOESS era. These will include C3S-provided space-to-ground connectivity, reliable and secure data delivery and insight & oversight of the total operation. For NPOESS the ground architecture is extended to provide additional ground receptor sites to reduce data product delivery times to users and delivery of additional sensor data products from sensors similar to NPP and more NPOESS sensors. This architecture is also extended from two Centrals (NESDIS & AFWA) to two additional Centrals (FNMOC & NAVO). IDPS acts as a buffer minimizing changes in how users request and receive data products.