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1

New estimates of silicate weathering rates and their uncertainties in global rivers  

NASA Astrophysics Data System (ADS)

This study estimated the catchment- and global-scale weathering rates of silicate rocks from global rivers using global compilation datasets from the GEMS/Water and HYBAM. These datasets include both time-series of chemical concentrations of major elements and synchronous discharge. Using these datasets, we first examined the sources of uncertainties in catchment and global silicate weathering rates. Then, we proposed future sampling strategies and geochemical analyses to estimate accurate silicate weathering rates in global rivers and to reduce uncertainties in their estimates. For catchment silicate weathering rates, we considered uncertainties due to sampling frequency and variability in river discharge, concentration, and attribution of weathering to different chemical sources. Our results showed that uncertainties in catchment-scale silicate weathering rates were due mostly to the variations in discharge and cation fractions from silicate substrates. To calculate unbiased silicate weathering rates accounting for the variations from discharge and concentrations, we suggest that at least 10 and preferably ?40 temporal chemical data points with synchronous discharge from each river are necessary. For the global silicate weathering rate, we examined uncertainties from infrequent sampling within an individual river, the extrapolation from limited rivers to a global flux, and the inverse model selections for source differentiation. For this weathering rate, we found that the main uncertainty came from the extrapolation to the global flux and the model configurations of source differentiation methods. This suggests that to reduce the uncertainties in the global silicate weathering rates, coverage of synchronous datasets of river chemistry and discharge to rivers from tectonically active regions and volcanic provinces must be extended, and catchment-specific silicate end-members for those rivers must be characterized. With current available synchronous datasets, we suggest that the global silicate weathering rate (Ca + Mg silicate weathering flux) was ?2.17 (2 ? range of 1.59-2.75) × 1012 mol/yr, and the global CO2 consumption rates from silicate weathering was ?7.85 (5.78-9.93) × 1012 mol/yr. Since current synchronous datasets are not available for some rivers in tectonically active regions and highly active volcanic rocks, our estimate should be considered as lower limit of estimates. Including the estimates from volcanic provinces from Dessert et al. (2003), the global CO2 consumption rates from silicates can be estimated as 11.93 (9.86-14.01) × 1012 mol/yr, which is similar to the previous estimates of Gaillardet et al. (1999).

Moon, Seulgi; Chamberlain, C. P.; Hilley, G. E.

2014-06-01

2

A framework for predicting global silicate weathering and CO2 drawdown rates over geologic time-scales  

PubMed Central

Global silicate weathering drives long-time-scale fluctuations in atmospheric CO2. While tectonics, climate, and rock-type influence silicate weathering, it is unclear how these factors combine to drive global rates. Here, we explore whether local erosion rates, GCM-derived dust fluxes, temperature, and water balance can capture global variation in silicate weathering. Our spatially explicit approach predicts 1.9–4.6 × 1013 mols of Si weathered globally per year, within a factor of 4–10 of estimates of global silicate fluxes derived from riverine measurements. Similarly, our watershed-based estimates are within a factor of 4–18 (mean of 5.3) of the silica fluxes measured in the world's ten largest rivers. Eighty percent of total global silicate weathering product traveling as dissolved load occurs within a narrow range (0.01–0.5 mm/year) of erosion rates. Assuming each mol of Mg or Ca reacts with 1 mol of CO2, 1.5–3.3 × 108 tons/year of CO2 is consumed by silicate weathering, consistent with previously published estimates. Approximately 50% of this drawdown occurs in the world's active mountain belts, emphasizing the importance of tectonic regulation of global climate over geologic timescales.

Hilley, George E.; Porder, Stephen

2008-01-01

3

Transport limitation of the silicate weathering negative feedback on global temperature: implications for the Neoproterozoic glaciations  

NASA Astrophysics Data System (ADS)

One of the foundation ideas of earth system science is that there is a negative feedback on global temperatures that operates via the carbonate-silicate weathering cycle: Buildup of CO2 in the atmosphere leads to higher temperatures. These increases silicate weathering, that in turn removes more CO2. However, the supply of material for silicate weathering is itself limited by the tectonic cycle, and this limits the effectiveness of the negative feedback at high global temperatures. Here we show using a very simple model of the geological carbon cycle that this limitation can readily lead to long-period snowball-greenhouse oscillations, with intervals between extreme glaciations of order tens of millions of years. We suggest that this is the explanation of the series of very severe glaciations during the Neoproterozoic. Our simple model gives qualitatively consistent estimates of excursions in carbonate ?13C during this time period, and suggests a large flux of oxygen to the atmosphere, broadly consistent with data.

Watson, A. J.; Mills, B.; Goldblatt, C.; Boyle, R. A.; Lenton, T.

2011-12-01

4

Global silicate weathering and CO 2 consumption rates deduced from the chemistry of large rivers  

Microsoft Academic Search

The main problem associated with the study of silicate weathering using river dissolved load is that the main control of solute chemistry is lithology and that all rivers are influenced by carbonate and evaporite weathering. In this paper, newly compiled data on the 60 largest rivers of the world are used to calculate the contribution of main lithologies, rain and

J. Gaillardet; B. Dupré; P. Louvat; C. J. Allègre

1999-01-01

5

Hf and Nd isotopes in marine sediments: Constraints on global silicate weathering  

NASA Astrophysics Data System (ADS)

The combined use of Lu-Hf and Sm-Nd isotope systems potentially offers a unique perspective for investigating continental erosion, but little is known about whether, and to what extent, the Hf-Nd isotope composition of sediments is related to silicate weathering intensity. In this study, Hf and Nd elemental and isotope data are reported for marine muds, leached Fe-oxide fractions and zircon-rich turbidite sands collected off the Congo River mouth, and from other parts of the SE Atlantic Ocean. All studied samples from the Congo fan (muds, Fe-hydroxides, sands) exhibit indistinguishable Nd isotopic composition (? Nd ~ - 16), indicating that Fe-hydroxides leached from these sediments correspond to continental oxides precipitated within the Congo basin. In marked contrast, Hf isotope compositions for the same samples exhibit significant variations. Leached Fe-hydroxide fractions are characterized by ? Hf values (from - 1.1 to + 1.3) far more radiogenic than associated sediments (from - 7.1 to - 12.0) and turbidite sands (from - 27.2 to - 31.6). ? Hf values for Congo fan sediments correlate very well with Al/K (i.e. a well-known index for the intensity of chemical weathering in Central Africa). Taken together, these results indicate that (1) silicate weathering on continents leads to erosion products having very distinctive Hf isotope signatures, and (2) a direct relationship exists between ? Hf of secondary clay minerals and chemical weathering intensity. These results combined with data from the literature have global implications for understanding the Hf-Nd isotope variability in marine precipitates and sediments. Leached Fe-hydroxides from Congo fan sediments plot remarkably well on an extension of the 'seawater array' (i.e. the correlation defined by deep-sea Fe-Mn precipitates), providing additional support to the suggestion that the ocean Hf budget is dominated by continental inputs. Fine-grained sediments define a diffuse trend, between that for igneous rocks and the 'seawater array', which we refer to as the 'zircon-free sediment array' (? Hf = 0.91 ? Nd + 3.10). Finally, we show that the Hf-Nd arrays for seawater, unweathered igneous rocks, zircon-free and zircon-bearing sediments (? Hf = 1.80 ? Nd + 2.35) can all be reconciled, using Monte Carlo simulations, with a simple weathering model of the continental crust.

Bayon, G.; Burton, K. W.; Soulet, G.; Vigier, N.; Dennielou, B.; Etoubleau, J.; Ponzevera, E.; German, C. R.; Nesbitt, R. W.

2009-01-01

6

Orbital-scale changes in the global silicate weathering intensity: the Mesozoic bedded chert sequence in Japan as its potential measure  

NASA Astrophysics Data System (ADS)

Silicate weathering is one of the most important regulators of the Earth system dynamics through nutrient supply and consumption of atmospheric CO2. However, its changes in the geologic past using geologic records have been controversial due to the lack of appropriate method to quantitatively reconstruct the past global silicate weathering intensity. One way for its measurement would be an estimation of the pelagic biogenic silica burial rate, because the silicate weathering and pelagic biogenic silica burial are the major source and major sink of dissolved silica in the present ocean, respectively (e.g. Treguer et al., 1995). During the Mesozoic, the pelagic bedded chert is the potential major sink of the biogenic silica in the ocean. We therefore first estimate the biogenic silica burial rate for the Inuyama bedded chert in Japan based on the major elements chemical analysis of individual chert and shale beds on the continuous sequence with bed-by-bed resolution. The rhythmically alternation of chert and shale beds were reflected by the precession cycle (Ikeda et al., 2010). By using the chert-shale couplet as time scale, we reconstructed the variation in the biogenic silica burial rate for the Inuyama bedded chert from the Early Triassic to Early Jurassic. Together with paleogeographic distribution of bedded chert compiled from previous studies, the biogenic silica burial rate in the low latitude Panthalassa ocean in the form of bedded chert was several times higher than the biogenic silica burial rate in the modern global ocean (DeMaster, 2002). This result suggests that bedded chert was the major sink of the dissolved silica in the ocean at least during the early Mesozoic. Therefore, the variations in the biogenic silica burial rate for bedded chert should be proportional to the variations in the dissolved silica input to the ocean in time-scales longer than its residence time in the ocean (15 kyr; Treguer et al., 1995). The variation in 87Sr/86Sr isotopic ratio, which is a possible measure for the global silicate weathering rate assuming the constant hydrothermal flux, show similar relative amplitude and phase of changes in the biogenic silica burial rate for the Inuyama bedded chert, except for the interval of increased hydrothermal flux during the Early Jurassic. Our results support the idea that the biogenic silica burial rate for bedded chert was the potential measure for the global silicate weathering intensity.

Ikeda, M.; Tada, R.; Olsen, P. E.

2012-12-01

7

Seawater Li and d7Li: Proxies for Silicate Weathering?  

NASA Astrophysics Data System (ADS)

This paper presents (i) the first systematic survey of lithium and its isotopes in the dissolved load and suspended and bed sediments of Himalayan rivers, and (ii) multi-species records of the Li/Ca ratio and Li isotopic composition of planktonic foraminifera from the Pacific and Atlantic oceans for the past 18 Ma. Modelling of the dissolved composition of Himalayan rivers indicates that most of the dissolved Li is derived from silicates even in carbonate-dominated catchments. Moreover, fractionation of Li isotopes between the dissolved and suspended load is lower at low altitiude where weathering is more intense. These data thus suggest that riverine Li fluxes largely reflect silicate weathering rates, while riverine ?7Li varies with weathering intensity. Given this information, and that the hydrothermal flux of Li into the oceans and the flux of Li removed from the oceans during low-temperature uptake by marine basalts and sediments have not changed significantly since 18 Ma and using published data for changing seawater calcium concentration, we can therefore interpret our planktonic foraminiferal Li/Ca and ?7Li records in terms of global average river ?7Li and Li fluxes. These records suggest that both silicate weathering rates and weathering intensity decreased between 16 and ~6Ma which may have been responsible for putative increases in levels of atmospheric CO2. In contrast, silicate weathering rates and weathering intensity appear to have increased since ~6Ma despite global cooling and apparently little variation in atmospheric CO2.

James, R. H.; Hathorne, E. C.; Kisakurek, B.; Harris, N. B.

2005-12-01

8

Tectonic and climatic controls on long-term silicate weathering in Asia since 5 Ma  

NASA Astrophysics Data System (ADS)

Determining the interplay between tectonic deformation, climate, atmospheric CO2 concentrations and continental weathering and erosion is key to understanding the mechanisms that forced Cenozoic global cooling. In contrast with studies of paleo-climate and pCO2, the history of long-term silicate weathering in the Himalaya and Tibetan Plateau (HTP) during the late Cenozoic remains unclear. We reconstruct 5 m.y. of silicate sedimentary records at Ocean Drilling Program (ODP) Site 1143 in the South China Sea to explore the weathering history of the Mekong River basin that supplied the sediment. Coherent variation of weathering proxies from the South China Sea, Bay of Bengal, Loess Plateau, as well as the Yangtze and Yellow Rivers, indicates weakening chemical weathering intensity since the late Pliocene, as the climate cooled. This cooling, coupled with tectonic activity, shifted the dominant weathering regime from more transport-limited to more weathering-limited, causing less chemical depletion of silicate minerals. While silicate weathering rates became strongly correlated to erosion rates, they were decoupled from chemical weathering intensity. Physical denudation and associated silicate weathering rates in the HTP area increased in the Pliocene, driven by both rock uplift and stronger monsoon precipitation, decreasing atmospheric CO2 concentrations, and so contributing to Northern Hemisphere Glaciation (NHG).

Wan, S.; Clift, P. D.; Li, A.; Yu, Z.; Li, T.; Hu, D.

2012-12-01

9

Tectonic and climatic controls on long-term silicate weathering in Asia since 5 Ma  

NASA Astrophysics Data System (ADS)

Determining the interplay between tectonic deformation, climate, atmospheric CO2 concentrations and continental weathering and erosion is key to understanding the mechanisms that forced Cenozoic global cooling. In contrast with studies of paleo-climate and pCO2, the history of long-term silicate weathering in the Himalaya and Tibetan Plateau (HTP) during the late Cenozoic remains unclear. We reconstruct 5 m.y. of silicate sedimentary records at Ocean Drilling Program (ODP) Site 1143 in the South China Sea to explore the weathering history of the Mekong River basin that supplied the sediment. Coherent variation of weathering proxies from the South China Sea, Bay of Bengal, Loess Plateau, as well as the Yangtze and Yellow Rivers, indicates weakening chemical weathering intensity since the late Pliocene, as the climate cooled. This cooling, coupled with tectonic activity, shifted the dominant weathering regime from more transport-limited to more weathering-limited, causing less chemical depletion of silicate minerals. While silicate weathering rates became strongly correlated to erosion rates, they were decoupled from chemical weathering intensity. Physical denudation and associated silicate weathering rates in the HTP area increased in the Pliocene, driven by both rock uplift and stronger monsoon precipitation, decreasing atmospheric CO2 concentrations, and so contributing to Northern Hemisphere Glaciation (NHG).

Wan, Shiming; Clift, Peter D.; Li, Anchun; Yu, Zhaojie; Li, Tiegang; Hu, Dengke

2012-08-01

10

Role of Fulvic Acids During the Weathering of Silicate Minerals.  

National Technical Information Service (NTIS)

The processes of migration and accumulation of aluminum in different crusts produced from weathering are studied by analyzing the decomposition conditions of silicate minerals by humic soil acids. (Author)

Y. I. Sokolova

1973-01-01

11

The geoengineering potential of artificially enhanced silicate weathering of olivine  

NASA Astrophysics Data System (ADS)

Geoengineering is a proposed action to manipulate Earth's climate in order to counteract global warming from anthropogenic greenhouse gas emissions. We investigate in more detail the potential of a specific geoengineering technique, the carbon sequestration by artificially enhanced silicate weathering via the dissolution of olivine. This approach would not only operate against rising temperatures but would also oppose ocean acidification, because it influences the global climate via the carbon cycle. We here show the consequences of this technique for the chemistry of the surface ocean at rates necessary for geoengineering. We calculate that olivine dissolution has the potential to sequestrate up to one Pg C yr-1 directly, if olivine is distributed as fine powder over land areas of the humid tropics. The carbon sequestration potential is limited by the saturation concentration of silicic acid. In our calculations for the Amazon and Congo river catchments a maximum annual dissolution of 1.8 and 0.4 Pg of olivine seems possible, corresponding to the sequestration of 0.5 and 0.1 Pg C yr-1. Open water dissolution of fine grained olivine and an enhancement of the biological pump by the rising riverine input of silicic acid might increase our estimate of the carbon sequestration, but additional research is needed here. We finally calculate with a carbon cycle model the consequences of sequestration rates of 1 to 5 Pg C yr-1 for the 21st century by this technique. At maximum this technique would reduce global warming by 1 K and counteract ocean acidification by a rise in surface ocean pH by 0.1 in the year 2100.

Köhler, Peter; Hartmann, Jens; Wolf-Gladrow, Dieter A.

2010-05-01

12

Geoengineering potential of artificially enhanced silicate weathering of olivine  

PubMed Central

Geoengineering is a proposed action to manipulate Earth’s climate in order to counteract global warming from anthropogenic greenhouse gas emissions. We investigate the potential of a specific geoengineering technique, carbon sequestration by artificially enhanced silicate weathering via the dissolution of olivine. This approach would not only operate against rising temperatures but would also oppose ocean acidification, because it influences the global climate via the carbon cycle. If important details of the marine chemistry are taken into consideration, a new mass ratio of CO2 sequestration per olivine dissolution of about 1 is achieved, 20% smaller than previously assumed. We calculate that this approach has the potential to sequestrate up to 1 Pg of C per year directly, if olivine is distributed as fine powder over land areas of the humid tropics, but this rate is limited by the saturation concentration of silicic acid. In our calculations for the Amazon and Congo river catchments, a maximum annual dissolution of 1.8 and 0.4 Pg of olivine seems possible, corresponding to the sequestration of 0.5 and 0.1 Pg of C per year, but these upper limit sequestration rates come at the environmental cost of pH values in the rivers rising to 8.2. Open water dissolution of fine-grained olivine and an enhancement of the biological pump by the rising riverine input of silicic acid might increase our estimate of the carbon sequestration, but additional research is needed here. We finally calculate with a carbon cycle model the consequences of sequestration rates of 1–5 Pg of C per year for the 21st century by this technique.

Kohler, Peter; Hartmann, Jens; Wolf-Gladrow, Dieter A.

2010-01-01

13

Geoengineering potential of artificially enhanced silicate weathering of olivine.  

PubMed

Geoengineering is a proposed action to manipulate Earth's climate in order to counteract global warming from anthropogenic greenhouse gas emissions. We investigate the potential of a specific geoengineering technique, carbon sequestration by artificially enhanced silicate weathering via the dissolution of olivine. This approach would not only operate against rising temperatures but would also oppose ocean acidification, because it influences the global climate via the carbon cycle. If important details of the marine chemistry are taken into consideration, a new mass ratio of CO(2) sequestration per olivine dissolution of about 1 is achieved, 20% smaller than previously assumed. We calculate that this approach has the potential to sequestrate up to 1 Pg of C per year directly, if olivine is distributed as fine powder over land areas of the humid tropics, but this rate is limited by the saturation concentration of silicic acid. In our calculations for the Amazon and Congo river catchments, a maximum annual dissolution of 1.8 and 0.4 Pg of olivine seems possible, corresponding to the sequestration of 0.5 and 0.1 Pg of C per year, but these upper limit sequestration rates come at the environmental cost of pH values in the rivers rising to 8.2. Open water dissolution of fine-grained olivine and an enhancement of the biological pump by the rising riverine input of silicic acid might increase our estimate of the carbon sequestration, but additional research is needed here. We finally calculate with a carbon cycle model the consequences of sequestration rates of 1-5 Pg of C per year for the 21st century by this technique. PMID:21059941

Köhler, Peter; Hartmann, Jens; Wolf-Gladrow, Dieter A

2010-11-23

14

Evolution of trees and mycorrhizal fungi intensifies silicate mineral weathering.  

PubMed

Forested ecosystems diversified more than 350 Ma to become major engines of continental silicate weathering, regulating the Earth's atmospheric carbon dioxide concentration by driving calcium export into ocean carbonates. Our field experiments with mature trees demonstrate intensification of this weathering engine as tree lineages diversified in concert with their symbiotic mycorrhizal fungi. Preferential hyphal colonization of the calcium silicate-bearing rock, basalt, progressively increased with advancement from arbuscular mycorrhizal (AM) to later, independently evolved ectomycorrhizal (EM) fungi, and from gymnosperm to angiosperm hosts with both fungal groups. This led to 'trenching' of silicate mineral surfaces by AM and EM fungi, with EM gymnosperms and angiosperms releasing calcium from basalt at twice the rate of AM gymnosperms. Our findings indicate mycorrhiza-driven weathering may have originated hundreds of millions of years earlier than previously recognized and subsequently intensified with the evolution of trees and mycorrhizas to affect the Earth's long-term CO(2) and climate history. PMID:22859556

Quirk, Joe; Beerling, David J; Banwart, Steve A; Kakonyi, Gabriella; Romero-Gonzalez, Maria E; Leake, Jonathan R

2012-12-23

15

Grasslands, silicate weathering and diatoms: Cause and effect  

SciTech Connect

Diatoms are silica-limited, photosynthetic, single-celled eukaryotes that today occupy a wide variety of habitats both in freshwater and marine environments. Ultimately the silica they use is derived from the weathering of silicates on land. Although marine diatoms first appear in the Jurassic, the fossil record shows a remarkable correlation between the Mid-Miocene appearance of widespread grasslands and the drastic increase in diatom-rich deposits in freshwater, as well as in marine environments throughout the world. Grasses actively weather silicates, accumulating soluble silica into their leaves. Decomposing grasses release this soluble silica into the soil from whence it is transported into lakes and oceans and made available to diatoms. Grasses also probably increased chemical weathering, and hence the release of soluble silica, in previously weakly vegetated semi-arid areas. Increased weathering of silicates also led to cooler climates as evidenced by the Mid-Miocene [delta][sup 18]O record. The author suggests that the Tertiary expansion of grasslands is responsible for the explosive increase in diversity and abundance of diatoms in the oceans and freshwaters of the Mid-Miocene.

Johansson, A.K. (Columbia Univ., Palisades, NY (United States). Dept. of Geological Sciences)

1993-03-01

16

Chemical weathering in the Hong (Red) River basin: Rates of silicate weathering and their controlling factors  

NASA Astrophysics Data System (ADS)

The Hong (Red) River drains the prominent Red River Fault Zone that has experienced various tectonic activities—intrusion of magma, exhumation of basement rocks, and influx of thermal waters—associated with the Cenozoic collision of India and Eurasia. We report dissolved major element and Sr isotope compositions of 43 samples from its three tributary systems (Da, Thao/Hong main channel, and Lo) encompassing summer and winter seasons. Carbonic acid ultimately derived from the atmosphere is the main weathering agent, and sulfuric acid from pyrite oxidation plays a minor role. Seasonality is manifested in higher calcite saturation index and Mg/TZ + and lower Ca/Mg in summer, suggesting calcite precipitation, and in higher Si/(Na ? + K) ratios in summer suggesting more intensive silicate weathering. We quantified the input from rain, evaporite, carbonate, and silicate reservoirs using forward and inverse models and examined the robustness of the results. Carbonate dissolution accounts for a significant fraction of total dissolved cations (55-97%), and weathering of silicates makes a minor contribution (1-40%). Our best estimate of the spatially averaged silicate weathering rate in the Hong basin is 170 × 10 3 mol/km 2/yr in summer and 51 × 10 3 mol/km 2/yr in winter. We tested for correlations between the rate of CO 2 consumption by silicate weathering and various climatic (air temperature, precipitation, runoff, and potential evapotranspiration) and geologic (relief, elevation, slope, and lithology) parameters calculated using GIS. Clear correlations do not emerge (except for ?CO 2 and runoff in winter) which we attribute to the complex geologic setting of the area, the seasonal regime change from physical-dominant in summer to chemical-dominant in winter, and the incoherent timescales involved for the different parameters tested.

Moon, Seulgi; Huh, Youngsook; Qin, Jianhua; van Pho, Nguyen

2007-03-01

17

Global CO2-consumption by chemical weathering: What is the contribution of highly active weathering regions?  

NASA Astrophysics Data System (ADS)

CO2-consumption by chemical weathering of silicates and resulting silicate/carbonate weathering ratios influences the terrestrial lateral inorganic carbon flux to the ocean and long-term climate changes. However, little is known of the spatial extension of highly active weathering regions and their proportion of global CO2-consumption. As those regions may be of significant importance for global climate change, global CO2-consumption is calculated here at high resolution, to adequately represent them. In previous studies global CO2-consumption is estimated using two different approaches: i) a reverse approach based on hydrochemical fluxes from large rivers and ii) a forward approach applying spatially explicit a function for CO2-consumption. The first approach results in an estimate without providing a spatial resolution for highly active regions and the second approach applied six lithological classes while including three sediment classes (shale, sandstone and carbonate rock) based at a 1° or 2° grid resolution. It remained uncertain, if the applied lithological classification schemes represent adequately CO2-consumption from sediments on a global scale (as well as liberation of other elements like phosphorus or silicon by chemical weatheirng). This is due to the large variability of sediment properties, their diagenetic history and the contribution from carbonates apparent in silicate dominated lithological classes. To address these issues, a CO2-consumption model, trained at high-resolution data, is applied here to a global vector based lithological map with 15 lithological classes. The calibration data were obtained from areas representing a wide range of weathering rates. Resulting global CO2-consumption by chemical weathering is similar to earlier estimates (237 Mt C a-1) but the proportion of silicate weathering is 63%, and thus larger than previous estimates (49 to 60%). The application of the enhanced lithological classification scheme reveals that it is important to distinguish among the various types of sedimentary rocks and their diagenetic history to evaluate the spatial distribution of rock weathering and thus lateral inorganic carbon fluxes. Results highlight the role of hotspots (>10 times global average weathering rates) and hyperactive areas (5 to 10 times global average rates). Only 9% of the global exorheic area is responsible for about 50% of CO2- consumption by chemical weathering (or if hotspots and hyperactive areas are considered: 3.4% of exorheic surface area corresponds to 28% of global CO2-consumption). The contribution of endorheic areas to the global CO2-consumption is with 3.7 Mt C a-1 only minor. A significant impact on the global CO2-consumption rate can be expected if identified highly active areas are affected by changes in the overall spatial patterns of the hydrological cycle due to ongoing global climate change. Specifically if comparing the Last Glacial Maximum with present conditions it is probable that also the global carbon cycle has been affected by those changes. It is expected that results will contribute to improve global carbon and global circulation models. In addition, recognizing chemical weathering rates and geochemical composition of certain lithological classes may be of value for studies focusing on biological aspects of the carbon cycles (e.g. studies needing information on the abundance of phosphorus or silica in the soil or aquatic system). Reference: Hartmann, J., Kempe, S, Dürr, H.H., Jansen, N. (2009) Global CO2-consumption by chemical weathering: What is the contribution of highly active weathering regions?. Global and Planetary Change, 69, 185-194. doi:10.1016/j.gloplacha.2009.07.007

Hartmann, Jens; Jansen, Nils; Dürr, Hans H.; Kempe, Stephan; Köhler, Peter

2010-05-01

18

Value of global weather sensors  

SciTech Connect

Long-range weather predictions have great scientific and economic potential, but require precise global observations. Small balloon transponders could serve as lagrangian trace particles to measure the vector wind, which is the primary input to long-range numerical forecasts. The wind field is difficult to measure; it is at present poorly sampled globally. Distance measuring equipment (DME) triangulation of signals from roughly a million transponders could sample it with sufficient accuracy to support {approximately} two week forecasts. Such forecasts would have great scientific and economic potential which is estimated below. DME uses small, low-power transmitters on each transponder to broadcast short, low-power messages that are detected by several small receivers and forwarded to the ground station for processing of position, velocity, and state information. Thus, the transponder is little more than a balloon with a small radio, which should only weigh a few grams and cost a few dollars.

Canavan, G.H.

1998-12-23

19

Global warming, bad weather, insurance losses and the global economy  

SciTech Connect

Global warming causes extremely bad weather in the near term. The impact on the insurance industry is described. Why global warming in the near term causes very bad weather is explained. The continuing trend of very bad weather and the future impact on the insurance industry is explored. How very bad weather can affect the global financial market is explained. Taking a historical view of the development of the modern economy, the authors describe in the near term the impact of global warming on the global economy. The long term impact of global warming on the global economy and the human race is explored. Opportunities presented by global warming are described.

Low, N.C. [UOB Life Assurance Ltd., Singapore (Singapore); Shen, S. [Global Warming International Center, Woodridge, IL (United States)

1996-09-01

20

A new CO 2 disposal process via artificial weathering of calcium silicate accelerated by acetic acid  

Microsoft Academic Search

A new disposal process for anthropogenic CO2 via an artificially accelerated weathering reaction is proposed to counteract global warming. The process is essentially composed of the following two steps:(1)CaSiO3+2CH3COOH?Ca2++2CH3COO?+H2O+SiO2(2)Ca2++2CH3COO?+CO2+H2O?CaCO3?+2CH3COOHStep (1) is the extraction of calcium ions by acetic acid from calcium silicate, for example, wollastonite rocks. Step (2) is the deposition of calcium carbonate from the solution of calcium ions

M. Kakizawa; A. Yamasaki; Y. Yanagisawa

2001-01-01

21

Geochemistry of dissolved and suspended loads of the Seine River, France: anthropogenic impact, carbonate and silicate weathering  

NASA Astrophysics Data System (ADS)

This study focuses on the chemistry of the Seine river system, one of the major rivers in Europe, and constitutes the first geochemical investigation of both suspended and dissolved loads of this river. The Seine river drains a typical Mesozoic-Cenozoic sedimentary basin: the Paris basin, constituted of limestones mixed or interbedded with terrigenous sediments derived from the paleoreliefs bordering the Mesozoic and Cenozoic seas. In the context of quantifying the global influence of carbonate and silicate weathering on atmospheric CO 2 consumption, the Seine river offers the possibility of examining weathering rates in a flat sedimentary environment, under temperate climatic conditions. One of the major problems associated with the Seine river, as with many temperate rivers, is pollution. We propose, in this paper, 2 approaches in order to correct the dissolved load of the Seine river for anthropogenic inputs and to calculate weathering rates of carbonates and silicates. The first uses the dissolved load of rivers and tries to allocate the different solutes to different sources. A mixing model, based on elemental ratios, is established and solved by an inversion technique. The second approach consists in using the suspended load geochemistry. Under steady state conditions, we show that the geochemistry of suspended sediments makes it possible to estimate the amount of solutes released during the chemical weathering of silicates, and thus to calculate weathering rates of silicates. The total dissolved load of the Seine river at Paris can be decomposed into 2% of solutes derived from natural atmospheric sources, 7% derived from anthropogenic atmospheric sources, 6% derived from agriculture, 3% derived from communal inputs, and 82% of solutes derived from rock weathering. During high floods, the contribution of atmospheric and agriculture inputs predominates. The weathering rate of carbonates is estimated to be 48 t/km 2/yr (25 mm/1000 yr). Only 10% of carbonates are transported in a solid form, the rest being transported in solution. CO 2 consumption by carbonate weathering approaches 400 × 10 3 mol/km 2/yr. In the Seine river at Paris, about 2-3 mg/l of dissolved cations are found to originate from the chemical weathering of silicates. By taking dissolved silica into accounts, the total dissolved load derived from silicate weathering is about 6-7 mg/l. This value is minimal because biological uptake of silica probably occur in the Seine river. The chemical weathering rate of aluminosilicates is estimated to be 2 t/km 2/yr . The ratio of physical over chemical weathering of silicates range between 1 and 3 and the total (chemical and physical) erosion rates of sedimentary silicates are about 2-3 mm/kyr. The CO 2 consumption by silicate weathering 15-24 × 10 3 mol/km 2/yr and is independent of dissolved silica concentration. Silicate consumption is thus 20 times less than carbonate consumption in the Paris basin. Compared to the neighboring granitic areas, the sedimentary region drained by the Seine river has 2 to 3 times lower CO 2 consumption rates. We attribute this difference to the cation-depleted nature of the Seine basin aluminosilicates, which are of sedimentary origin. At a world scale, the chemical denudation rates found for the Seine basin are very low and comparable to those given for tropical lowland rivers draining silicates, such as the rivers of the Congo and Amazon basins, in spite of huge climatic differences. We attribute this similarity to the low mechanical denudation that characterizes these two types of regions.

Roy, S.; Gaillardet, J.; Allègre, C. J.

1999-05-01

22

The effect of time on the weathering of silicate minerals: why do weathering rates differ in the laboratory and field?  

Microsoft Academic Search

The correlation between decreasing reaction rates of silicate minerals and increasing duration of chemical weathering was investigated for both experimental and field conditions. Column studies, using freshly prepared Panola Granite, produced ambient plagioclase weathering rates that decreased parabolically over 6 years to a final rate of 7.0×10?14 mol m?2 s?1. In contrast, the corresponding plagioclase reaction rate for partially kaolinized

Art F. White; Susan L. Brantley

2003-01-01

23

The significance of Himalayan rivers for silicate weathering rates: evidence from the Bhote Kosi tributary  

Microsoft Academic Search

The significance of weathering by Himalayan runoff for both the Sr-isotope marine record and the removal of atmospheric CO2 through silicate dissolution has been examined by systematic sampling of dissolved loads and bedloads from the Bhote Kosi, a tributary of the Ganges that rises in Tibet from Tethyan sediment bedrock and traverses the major Himalayan lithologies of eastern Nepal before

Nigel Harris; Mike Bickle; Hazel Chapman; Ian Fairchild; Judith Bunbury

1998-01-01

24

The effect of land plants on weathering rates of silicate minerals  

Microsoft Academic Search

Land plants and their associated microbiota directly affect silicate mineral weathering in several ways: by generation of chelating ligands, by modifying pH through production of CO 2 or organic acids, and by altering the physical properties of a soil, particularly the exposed surface areas of minerals and the residence time of water. In laboratory experiments far from equilibrium, 1 mM

James I. Drever

1994-01-01

25

Lithium isotope ratios measured in scottish rivers and weathering of old silicate rocks.  

NASA Astrophysics Data System (ADS)

Silicate weathering is often considered as one of the most important sinks of atmospheric CO2 over geological timescales, but the palaeovariations of the silicate weathering rates are still debated and depend on the reliability of the chosen proxies. It has recently been suggested that Li isotopes significantly fractionate during continental erosion (Huh et al., 1999), and that 7Li measured in large rivers could mainly reflect the degree of silicate weathering at large scales. Two main reasons have been proposed, the high Li contents in silicate minerals relative to carbonates, and the preferential uptake of 6Li by secondary clay minerals. Nevertheless, very few measurements have been made either on source minerals or on weathering products. In principle, the study of small silicated catchments should allow us to better constrain the factors controlling the fractionation of Li isotopes. A previous study has shown that 7Li measured in Icelandic basaltic rivers displays a large range (from 10 to 25.3) which correlates well with estimated weathering rates (Gislason et al., 1996). Here we present results for about 15 rivers located in Northern Scotland, which show little evidence for anthropogenic contamination, and draining mainly old silicated terrains (>500Ma). These rivers have been sampled twice, in May and in October 2002, in order to constrain the seasonal variations of the Li signature. Major and trace elements have also been measured, as well as the dissolved organic carbon. All rivers have very low Ca/Na and Mg/Na ratios (average of 0.38 and 0.17 respectively), that corresponds to the end-member previously defined for silicate rivers (Gaillardet et al, 1999), suggesting negligible contribution from carbonate dissolution. Li contents range between 0.2 and 1.2 ppb and are significantly greater than in Iceland rivers (up to 0.09 ppb). First results for the May 2002 samples show a restricted range in 7Li (from 16 to 22) relative to basaltic rivers of Iceland, and this range compares well with shield rivers of the Orinoco and the Mississipi basins (13 - 22). 7Li display negative trends with Ca/Na and Mg/Na, unlikely to be explained by carbonate dissolution since rivers with high Ca/Na and Mg/Na have higher Si content and lower 7Li. These trends could rather be explained by a mixing between a seawater component, probably of atmospheric origin, and an intensive weathering of Ca-Mg silicate minerals present in soils.

Vigier, N.; Reynolds, B. C.; Burton, K. W.; Rogers, N. W.

2003-04-01

26

Experimental Weathering of Silicates and Carbonates in a SO_2 Atmosphere: Implications for the Martian Surface Mineralogy  

NASA Astrophysics Data System (ADS)

Weathering experiments of carbonates and silicates in a SO_2 atmosphere and water or water plus hydrogen peroxide result in differences in nature and abundance of secondary phases, favoring sulfites in the first case and sulfates in the second.

Chevrier, V. F.; Lozano, C. G.; Altheide, T. S.

2012-03-01

27

Global chemical weathering and associated P-release  

NASA Astrophysics Data System (ADS)

Chemical weathering releases phosphorus to soils and ecosystems. To improve understanding of the spatial distribution of the global P-release characteristics, a model framework for estimating global chemical weathering rates was coupled with geochemical information. Results suggest that the global soil shielding reduces chemical weathering fluxes by about 44%, compared to an Earth surface with no deeply weathered soils but relatively young rock surfaces (e.g. as in volcanic arc and other tectonically active areas). About 70% of the weathering fluxes globally derive from 10% of the land area, with Southeast Asia being a primary "hot spot" of chemical weathering and for P-release. In contrast, only 50% of runoff is attributed to 10% of the land area; thus the global chemical weathering rating curve is to some extent disconnected from the global runoff curve due to the spatially heterogeneous climate as well as differences in rock and soil properties. In addition to total chemical weathering fluxes, the release of P, a nutrient that controls biological productivity at large spatial scales, is affected by the spatial correlation between runoff, lithology, temperature and soil properties. The areal abundance of deeply weathered soils in Earth's past may have influenced weathering fluxes and P-fuelled biological productivity significantly, specifically in the case of larger climate shifts when high runoff fields shift to areas with thinner soils or areas with more weatherable rocks and relatively increased P-content. This observation may be particularly important for spatially resolved Earth system models targeting geological time scales. The full research text can be found in: Hartmann, J., N. Moosdorf, R. Lauerwald, M. Hinderer, A.J. West (2014) Global chemical weathering and associated P-release - the role of lithology, temperature and soil properties. Chemical Geology 363, 145-163. doi: 10.1016/j.chemgeo.2013.10.025 (open access)

Hartmann, Jens; Moosdorf, Nils; Lauerwald, Ronny; Hinderer, Matthias; West, A. Joshua

2014-05-01

28

Investigating the Climate System: Weather- Global Awareness Tour  

NSDL National Science Digital Library

Through the scenario of planning concert locations for a "Global Awareness Tour", students will research, interpret, and explain general characteristics of weather in tropical regions. They will learn to use data from the Tropical Rainfall Measuring Mission (TRMM) satellite instruments to make observations on extreme weather situations, develop their Internet research skills, and enhance communication and presentation skills. This module is designed to be used at the end of a unit on weather. Students are expected to understand temperature, pressure, precipitation, clouds, winds, lightning, mid-latitude weather patterns, basic geography, and geographical influences on weather patterns. They should also be familiar with the TRMM satellite instruments and mission.

Passow, Michael

29

Space weathering of silicates simulated by nanosecond pulse UV excimer laser  

NASA Astrophysics Data System (ADS)

Laser irradiation experiments have been performed on powdered silicates (othopyroxene, clinopyroxene, and olivine) using a nanosecond pulse UV excimer laser (193 and 248 nm) to simulate the effects of space weathering induced on minor bodies of the Solar System by micrometeorite bombardment. We have used different fluences (from 0.05 to 2 J/cm 2) to weather the samples, experimenting below and above the ablation threshold. All the irradiated materials have shown reddening and darkening of their UV-vis-NIR reflectance spectra. In addition we have found that: (1) below ablation threshold, weathering effects increase with increasing number of laser pulses, and with increasing fluence, confirming that a thermal process is active; (2) above ablation threshold, weathering is much stronger and efficient than in the previous case, and is independent on the number of pulses. We show that astrophysical time-scales, i.e. times necessary to obtain similar effects on planetary objects, are of about 10 8 yr for both olivine and pyroxene in the case of ablation. The time grows up to 10 10 yr in the case of thermal effects. We infer that micrometeorite bombardment can be rightly simulated by laser irradiation only considering congruent laser ablation.

Brunetto, R.; Romano, F.; Blanco, A.; Fonti, S.; Martino, M.; Orofino, V.; Verrienti, C.

2006-02-01

30

Solar Coronal Topological Activity and Global Weather Patterns  

NASA Astrophysics Data System (ADS)

Mathematical and topological methods are used to define and describe solar coronal activity; observed as coronal mass ejections, solar flares and coronal holes. The associated variations of the plasma, magnetic field, particle flux, UV-, EUV-, and X-ray radiation are then related to changes of global weather patterns. The global weather patterns, North Atlantic Oscillation (NAO), Artic Oscillation (AO), and Pacific Decadal Oscialltion (PDO), are also analyzed with wavelet techniques.

Lundstedt, H.

2009-09-01

31

Probing The Surface Properties Of Weathered Silicate Minerals To Better Understand Their Reactivity  

NASA Astrophysics Data System (ADS)

While we expect conventional reactive transport simulations to provide reliable estimations of the evolution of fluid-rock interactions over time scales of centuries and even more, recent experimental studies showed that they could hardly be satisfactorily used on simplified systems (e.g. batch experiments on single minerals), on time scales of weeks [1]. As emphasized elsewhere [1, 2], the reasons for such inconsistencies have to be sought in the nature of the rate laws used in the geochemical codes, which heavily rely on our description of the fundamental mechanisms involved during water-mineral reactions. In that respect, the present ongoing work aims at gathering some of our recent findings in the dissolution kinetics of a series of Al-free silicates, in relation to the physicochemical properties of their surfaces after/during hydrothermal weathering. A first still unresolved issue that we are addressing is the effect of ubiquitous silica-rich layers which form on silicate minerals. While µm-thick silica coatings formed on the surface of wollastonite crystals without significantly affecting their dissolution rate, we observed that nm-thick silica coatings fully passivate the surface of olivine crystals [1, 3]. We will show how the use of microscopic (STEM, HTEM) [3] and spectroscopic (ToF-SIMS, XPS) techniques helped us to unravel these paradoxical properties, and which chemical parameters could influence the textural features of the layers. A different (or supplementary) mechanism possibly responsible for unexpected decreases of silicate dissolution rate at “far-from-equilibrium” conditions (e.g. diopside, [4]) was proposed to arise from the surface topography of the dissolving crystals and the occurrence (or absence) of etch pits [5]. We will show how the in situ monitoring of the dissolving surface of diopside as a function of fluid saturation state in a HAFM flow-cell (e.g. [6]) is allowing us to address this question. [1] Daval et al (2010) Proceed WRI-13, 1, 713-716 [2] Zhu (2009) Rev Mineral Geochem, 70, 533-569 [3] Daval et al (2009) Am Mineral, 94, 1707-1726 [4] Daval el al (2010) Geochim Cosmochim Ac, 74, 2615-2633 [5] Arvidson & Luttge (2010) Chem Geol, 269, 79-88 [6] Saldi et al (2009) Geochim Cosmochim Ac, 73, 5646-5657

Daval, D.; Sissmann, O.; Saldi, G. D.; Hellmann, R.; Gin, S.; Corvisier, J.; Martinez, I.; Guyot, F. J.; Knauss, K. G.

2010-12-01

32

Electrochemical Acceleration of Carbonate and Silicate Weathering for CO2 Mitigation  

NASA Astrophysics Data System (ADS)

Carbonate and many silicate minerals dissolve in strong acids, and such acids are commonly generated at the anode of a conventional saline water electrolysis cell. It was therefore reasoned that encasing such an anode with base minerals would lead to enhanced mineral dissolution and hence increased hydroxide (base) generation at the cathode, formed in course of splitting water, generating H2 and OH-. Subsequent exposue of the alkalized solution to CO2 (e.g., as in air) would lead to absorption of the CO2 and formation of stable dissolved or solid (bi)carbonates for carbon sequestration. Previously, it has been demonstrated that mineral carbonate encasement of a seawater electrolysis cell anode indeed generated basic solutions in excess of pH 9 that were subsequently neutralized via contact with air CO2, increasing the carbon content of the initial seawater by 30% (Rau, G.H. 2008. Environ Sci. Techol. 42, 8935-). To test such a weathering/CO2 capture scheme using silicate minerals, either powdered wollastonite or ultramafic rock standard (UM-4) was encased around the anode of an electrolysis cell composed of graphite electrodes and a 0.25M Na2SO4 electrolyte solution. After 0.5 to 1.5 hrs of electricity application (3.5Vdc, 5-10mA), the electrolyte pH rose to as much as 11.1 (initial and blank solution pH's <6.6). Subequent bubbling of these basic solutions with air lowered pH by at least 2 units and increased dissolve carbon content (primarily bicarbonate) by as much as 50X that of the blanks. While Ca2+ and Mg2+ concentrations were elevated, these were insufficient to balance the majority of the bicarbonate anions formed in solution. This suggests that in these experiments the silicate minerals acted as a neutralizer of the anolyte acid, H2SO4, forming mostly insoluble CaSO4 and MgSO4 at the anode. This then allowed NaOH normally produced at the cathode to accumulate in solution, in turn reacting with air CO2 to form NaHCO3. Longer electrolysis times and/or alternative electrolyte solutions might allow formation and precipitation of Ca or Mg carbonates. Such electrochemistry might ultimately provide a safe, efficient way to harness the planet's: i) large, off-peak or off-grid renewable electricity potential, ii) abundant basic minerals, and iii) vast natural brine electrolytes for large-scale air CO2 mitigation and carbon-negative H2 production.

Rau, G. H.; Carroll, S.

2011-12-01

33

Global Weather Prediction Model Difference Schemes.  

National Technical Information Service (NTIS)

One case of analytic data and one case of real data were numerically integrated using a five level baroclinic primitive equation global model of the general circulation. The feasibility of using a mixed second order and fourth order space differencing sch...

W. F. Mihok

1974-01-01

34

Impact of derived global weather data on simulated crop yields.  

PubMed

Crop simulation models can be used to estimate impact of current and future climates on crop yields and food security, but require long-term historical daily weather data to obtain robust simulations. In many regions where crops are grown, daily weather data are not available. Alternatively, gridded weather databases (GWD) with complete terrestrial coverage are available, typically derived from: (i) global circulation computer models; (ii) interpolated weather station data; or (iii) remotely sensed surface data from satellites. The present study's objective is to evaluate capacity of GWDs to simulate crop yield potential (Yp) or water-limited yield potential (Yw), which can serve as benchmarks to assess impact of climate change scenarios on crop productivity and land use change. Three GWDs (CRU, NCEP/DOE, and NASA POWER data) were evaluated for their ability to simulate Yp and Yw of rice in China, USA maize, and wheat in Germany. Simulations of Yp and Yw based on recorded daily data from well-maintained weather stations were taken as the control weather data (CWD). Agreement between simulations of Yp or Yw based on CWD and those based on GWD was poor with the latter having strong bias and large root mean square errors (RMSEs) that were 26-72% of absolute mean yield across locations and years. In contrast, simulated Yp or Yw using observed daily weather data from stations in the NOAA database combined with solar radiation from the NASA-POWER database were in much better agreement with Yp and Yw simulated with CWD (i.e. little bias and an RMSE of 12-19% of the absolute mean). We conclude that results from studies that rely on GWD to simulate agricultural productivity in current and future climates are highly uncertain. An alternative approach would impose a climate scenario on location-specific observed daily weather databases combined with an appropriate upscaling method. PMID:23801639

van Wart, Justin; Grassini, Patricio; Cassman, Kenneth G

2013-12-01

35

The contribution of weathering of the main Alpine rivers on the global carbon cycle  

NASA Astrophysics Data System (ADS)

On geological time-scales the carbon fluxes from the solid Earth to the atmosphere mainly result from volcanism and metamorphic-decarbonation processes, whereas the carbon fluxes from atmosphere to solid Earth mainly depend on weathering of silicates and carbonates, biogenic precipitation and removal of CaCO3 in the oceans and volcanic gases - seawater interactions. Quantifying each contribution is critical. In this work, we estimate the atmospheric CO2 uptake by weathering in the Alps, using results of the study of the dissolved loads transported by 33 main Alpine rivers. The chemical composition of river water in unpolluted areas is a good indicator of surface weathering processes (Garrels and Mackenzie, 1971; Drever, 1982; Meybeck, 1984; Tardy, 1986; Berner and Berner, 1987; Probst et al., 1994). The dissolved load of streams originates from atmospheric input, pollution, evaporite dissolution, and weathering of carbonate and silicate rocks, and the application of mass balance calculations allows quantification of the different contributions. In this work, we applied the MEGA (Major Element Geochemical Approach) geochemical code (Amiotte Suchet, 1995; Amiotte Suchet and Probst, 1996) to the chemical compositions of the selected rivers in order to quantify the atmospheric CO2 consumed by weathering in Alpine region. The drainage basins of the main Alpine rivers were sampled near the basin outlets during dry and flood seasons. The application of the MEGA geochemical consisted in several steps. First, we subtracted the rain contribution in river waters knowing the X/Cl (X = Na, K, Mg, Ca) ratios of the rain. Next, we considered that all (Na+K) came from silicate weathering. The average molar ratio Rsil = (Na+K)/(Ca+Mg) for rivers draining silicate terrains was estimated from unpolluted French stream waters draining small monolithological basins (Meybeck, 1986; 1987). For the purpose, we prepared a simplified geo-lithological map of Alps according to the lithological classification of Meybeck (1986, 1987). Then for each basin we computed Rsil weighted average considering the surface and the mean precipitation for the surface area of each lithology. Lastly, we estimated the (Ca+Mg) originating from carbonate weathering as the remaining cations after silicate correction. Depending on time-scales of the phenomena (shorter than about 1 million year i.e., correlated to the short term carbon cycle, or longer than about 1 million years i.e., correlated to the long-term carbon cycle), we considered different equations for the quantification of the atmospheric CO2 consumed by weathering (Huh, 2010). The results show the net predominance of carbonate weathering on fixing atmospheric CO2 and that, considering the long-term carbon cycle, the amount of atmospheric CO2 uptake by weathering is about one order of magnitude lower than considering the short-term carbon cycle. Moreover, considering the short-term carbon cycle, the mean CO2 consumed by Alpine basins is of the same order of magnitude of the mean CO2 consumed by weathering by the 60 largest rivers of the world estimated by Gaillardet et al. (1999). References Amiotte-Suchet, P. "Cycle Du Carbone, Érosion Chimique Des Continents Et Transfert Vers Les Océans." Sci. Géol. Mém. Strasbourg 97 (1995): 156. Amiotte-Suchet, P., and J.-L. Probst. "Origins of dissolved inorganic carbon in the Garonne river waters: seasonal and interannual variations." Sci. Géologiques Bull. Strasbourg 49, no. 1-4 (1996): 101-126. Berner, E.K., and R.A. Berner. The Global Water Cycle. Geochemistry and Environment. Prentice Halle. Engelwood Cliffs, NJ, 1987. Drever, J.L. The Geochemistry of Natural Waters. Prentice Hall, 1982. Gaillardet, J., B. Dupré, P. Louvat, and C.J. Allègre. "Global Silicate Weathering and CO2 Consumption Rates Deduced from the Chemistry of Large Rivers." Chemical Geology 159 (1999): 3-30. Garrels, R.M., and F.T. Mackenzie. Evolution of Sedimentary Rocks. New York: W.W. Nortonand, 1971. Huh, Y. "Estimation of Atmospheric CO2 Uptake by Silicat

Donnini, Marco; Probst, Jean-Luc; Probst, Anne; Frondini, Francesco; Marchesini, Ivan; Guzzetti, Fausto

2013-04-01

36

Oceans Effect on Weather and Climate: Global Climate Patterns  

NSDL National Science Digital Library

This Science Object is the third of four Science Objects in the Ocean's Effect on Weather and Climate SciPack. It explores ocean circulation patterns and the effect oceans have on climate. Water in the oceans hold a lot of thermal energy (more than an equal amount of land). Throughout the ocean there is a global, interconnected circulation system that transfers this thermal energy across Earth. The shape of ocean basins and adjacent land masses influence the path of circulation. As ocean currents transfer thermal energy to various locations, the temperature of the atmosphere above the ocean is affected. For example, the condensation of water that has been evaporated from warm seas provides the energy for hurricanes and cyclones. When the pattern of thermal energy released into the atmosphere changes, global weather patterns are affected. An example of a large-scale change like this is the El Ni�o Southern Oscillation, which changes the pattern of thermal energy released into the atmosphere in the Pacific. Learning Outcomes:� Explain how the oceans might influence and affect local weather and climate, given a specific location (on the planet near the ocean) and the local ocean currents.� Describe the cause of hurricanes and explain why they usually occur within specific regions during certain times of the year.� Explain how changes in ocean temperatures (over a period of months) affect factors that influence weather patterns.� List the major variables that affect the transfer of energy through the ocean.

National Science Teachers Association (NSTA)

2007-03-28

37

Oceans Effect on Climate and Weather: Global Circulation Patterns  

NSDL National Science Digital Library

This Science Object explores ocean circulation patterns and the effect oceans have on climate. Water in the oceans hold a lot of thermal energy (more than an equal amount of land). Throughout the ocean there is a global, interconnected circulation system that transfers this thermal energy across Earth. The shape of ocean basins and adjacent land masses influence the path of circulation. As ocean currents transfer thermal energy to various locations, the temperature of the atmosphere above the ocean is affected. For example, the condensation of water that has been evaporated from warm seas provides the energy for hurricanes and cyclones. When the pattern of thermal energy released into the atmosphere changes, global weather patterns are affected. An example of a large-scale change like this is the El Ni�o Southern Oscillation, which changes the pattern of thermal energy released into the atmosphere in the Pacific. This Science Object is the third of four Science Objects in the Ocean's Effect on Weather and Climate SciPack. Learning Outcomes: � Explain how the oceans might influence and affect local weather and climate, given a specific location (on the planet near the ocean) and the local ocean currents. � Describe the cause of hurricanes and explain why they usually occur within specific regions during certain times of the year. � Explain how changes in ocean temperatures (over a period of months) affect factors that influence weather patterns. � List the major variables that affect the transfer of energy through the ocea

National Science Teachers Association (NSTA)

2007-03-28

38

Oceans Effect on Weather and Climate: Global Precipitation and Energy  

NSDL National Science Digital Library

This Science Object is the third of four Science Objects in the Ocean's Effect on Weather and Climate SciPack. It explores ocean circulation patterns and the effect oceans have on climate. Water in the oceans hold a lot of thermal energy (more than an equal amount of land). Throughout the ocean there is a global, interconnected circulation system that transfers this thermal energy across Earth. The shape of ocean basins and adjacent land masses influence the path of circulation. As ocean currents transfer thermal energy to various locations, the temperature of the atmosphere above the ocean is affected. For example, the condensation of water that has been evaporated from warm seas provides the energy for hurricanes and cyclones. When the pattern of thermal energy released into the atmosphere changes, global weather patterns are affected. An example of a large-scale change like this is the El Ni�o Southern Oscillation, which changes the pattern of thermal energy released into the atmosphere in the Pacific. Learning Outcomes:� Explain how the oceans might influence and affect local weather and climate, given a specific location (on the planet near the ocean) and the local ocean currents.� Describe the cause of hurricanes and explain why they usually occur within specific regions during certain times of the year.� Explain how changes in ocean temperatures (over a period of months) affect factors that influence weather patterns.� List the major variables that affect the transfer of energy through the ocean.

National Science Teachers Association (NSTA)

2007-03-28

39

The Global Distribution of Weathered Glass on Mars  

NASA Astrophysics Data System (ADS)

Weathered iron-bearing glass has been identified as the primary phase in over ten million square kilometers of low-albedo deposits in the northern lowlands of Mars, based on visible to near-infrared (0.36-2.5 ?m) spectra from the OMEGA imaging spectrometer onboard Mars Express (Horgan and Bell, 2012). The glass exhibits a concave blue slope in the near-infrared that is consistent with a leached glass rind. This rind is formed during exposure of glass to at least slightly acidic fluids under water-limited conditions, and is commonly observed in dry volcanic environments on Earth. The proposed origin for these materials is explosive volcanism, potentially triggered due to ice-magma interactions in the late Hesperian or Amazonian, followed by post-depositional acidic weathering at the surface. A possible analog for these glass-rich sedimentary terrains are the extensive sand plains, dune fields, and flood plains of Iceland, which are composed of glass-rich (50-90%) volcaniclastic sediments formed during sub-glacial eruptions. The large scale of the martian deposits suggests widespread (and potentially ice-related) explosive volcanism either in the northern lowlands or near the dichotomy boundary. This possibility raises the question: How widespread are glass-rich deposits on Mars globally? To address this question, we have developed a global set of visible/near-infrared OMEGA mosaics at 1 km/pixel resolution. Preliminary analysis of this data set indicates that the concave spectral slope that we associate with weathered glass is present in large portions of the Syrtis Major region, within Mawrth Vallis, and in several dozen dune fields in the regions of Syrtis Major, Arabia Terra, Valles Marineris, and the Argyre Basin. Higher resolution CRISM observations of several Valles Marineris dune fields appear to confirm these preliminary results, as spectra within the dune fields are consistent with iron-bearing glass (Chojnacki et al., 2012). We are currently working to extend this analysis globally, and to search for correlations with deposit types, sediment sources, and predicted distributions of pyroclastic deposits from the major volcanic edifices. However, even these preliminary results strongly suggest that weathered glass is a major component of global martian sediments. An additional source of information regarding the nature and distribution of these deposits is their inferred composition from thermal infrared spectra. The dark, glassy deposits of the northern lowlands are the type locality for the globally distributed TES Surface Type 2 (ST2) composition, which differs from the olivine-basaltic Surface Type 1 by requiring an additional high-silica component. Based on the correlation between the glass and ST2 in the northern lowlands, we hypothesize that the weathered glassy rinds may be the high-silica component of ST2 in this region. In order to determine whether there is a global correlation between ST2 and weathered glass, we have compared global maps of TES ST2 spectral indices with OMEGA weathered glass spectral indices. We have initially focused on dune fields as mapped by the Mars Global Digital Dunes Database, which reveal at least a qualitative correlation between ST2 and weathered glass. Further analysis will produce a quantitative comparison of the two data sets in the dune fields as well as in other low albedo terrains.

Horgan, B.; Chojnacki, M.; Lai, J.; Clarke, D.; Joseph, J.; Bell, J. F.

2012-12-01

40

Atlas of the global distribution of atmospheric heating during the global weather experiment  

NASA Technical Reports Server (NTRS)

Global distributions of atmospheric heating for the annual cycle of the Global Weather Experiment are estimated from the European Centre for Medium-Range Weather Forecasts (ECMWF) Level 3b data set. Distributions of monthly, seasonally, and annually averaged heating are presented for isentropic and isobaric layers within the troposphere and for the troposphere as a whole. The distributions depict a large-scale structure of atmospheric heating that appears spatially and temporally consistent with known features of the global circulation and the seasonal evolution.

Schaack, Todd K.; Johnson, Donald R.

1991-01-01

41

Silicate weathering of soil-mantled slopes in an active Alpine landscape  

NASA Astrophysics Data System (ADS)

Despite being located on high, steep, actively uplifting, and formerly glaciated slopes of the Swiss Central Alps, soils in the upper Rhone Valley are depleted by up to 50% in cations relative to their parent bedrock. This depletion was determined by a mass loss balance based on Zr as a refractory element. Both Holocene weathering rates and physical erosion rates of these slopes are unexpectedly low, as measured by cosmogenic 10Be-derived denudation rates. Chemical depletion fractions, CDF, range from 0.12 to 0.48, while the average soil chemical weathering rate is 33 ± 15 t km -2 yr -1. Both the cosmogenic nuclide-derived denudation rates and model calculations suggest that these soils have reached a weathering steady-state since deglaciation 15 ky ago. The weathering signal varies with elevation and hillslope morphology. In addition, the chemical weathering rates decrease with elevation indicating that temperature may be a dominant controlling factor on weathering in these high Alpine basins. Model calculations suggest that chemical weathering rates are limited by reaction kinetics and not the supply rate of fresh material. We compare hillslope and catchment-wide weathering fluxes with modern stream cation flux, and show that high relief, bare-rock slopes exhibit much lower chemical weathering rates despite higher physical erosion rates. The low weathering fluxes from rocky, rapidly eroding slopes allow for the broader implication that mountain building, while elevating overall denudation rates, may not cause increased chemical weathering rates on hillslopes. In order for this sediment to be weathered, intermediate storage, for instance in floodplains, is required.

Norton, Kevin P.; von Blanckenburg, Friedhelm

2010-09-01

42

Ca\\/Sr and Sr isotope systematics of a Himalayan glacial chronosequence: carbonate versus silicate weathering rates as a function of landscape surface age  

Microsoft Academic Search

We explored changes in the relative importance of carbonate vs. silicate weathering as a function of landscape surface age by examining the Ca\\/Sr and Sr isotope systematics of a glacial soil chronosequence located in the Raikhot watershed within the Himalaya of northern Pakistan. Bedrock in the Raikhot watershed primarily consists of silicate rock (Ca\\/Sr ? 0.20 ?mol\\/nmol, 87Sr\\/86Sr ? 0.77

ANDREW D. JACOBSON; J OEL D. BLUM; C. Page Chamberlain; MICHAEL A. POAGE; VALERIE F. SLOAN

2002-01-01

43

Behavior of Boron Isotopes During Chemical Weathering: a Global Approach  

NASA Astrophysics Data System (ADS)

Boron has two isotopes (10B and 11B) that fractionate largely during Earth surface processes. The major fractionating step takes place during low temperature water-rock interactions. Up to 20-30 \\permil difference in ? 11B units are shown to occur during the adsorption of boron onto surfaces or its precipitation into solids. Light boron has a much greater affinity for neoformed solids while the residual solution is enriched in heavy boron. For example, seawater has a boron isotopic composition of 40 \\permil, mainly due to the preferential removal of 10B during oceanic seafloor weathering, adsorption onto fluvial sediments and chemical weathering reactions occurring in soils. The high sensitivity of boron isotopes fractionation to water rock interactions make it a valuable tool to constrain chemical weathering processes. To have a global picture of the behavior of boron isotopes during chemical weathering of rocks at the surface of the continents, we analyzed the largest rivers for both the dissolved and suspended load. Dissolved boron isotopic compositions were published earlier ([Lemarchand et al., 2000]) and we here focus on the results for the suspended load and for the bottom sands. Boron clearly appears as a mobile element when its abundance in suspended sediments is normalized to upper continental material. Boron depletion in suspended solids is climate dependent, with higher depletion is warm climates. On average, more than 50 % of boron is transported to the ocean in a solid form. While the dissolved load of boron is clearly enriched in 11B (0 \\permil) with respect to the mean upper continental crust (-10 \\permil), isotopic composition of the suspended load of major rivers does not differ significantly from that of the continental crust. This result indicates that suspended material is not significantly fractionated with respect to the continental crust by chemical weathering processes or that the mass budget of boron partitioning between solids and water does not allow the residual solids to be significantly different from bedrock. This is supported by a Rayleigh distillation model. Our boron data, both in concentration and isotopic composition, give strong support to the idea that shale erosion is a major source of suspended sediments in large river system, making thus boron isotopes a good tracer of intra-continental recycling. Lemarchand et al., 2000, Nature, vol 408, pp 951-954.

Gaillardet, J.; Chetelat, B.

2004-12-01

44

A global review of solutional weathering forms on quartz sandstones  

NASA Astrophysics Data System (ADS)

Solutional landforms in limestone have been described for over a hundred years, but landforms of similar morphology on highly siliceous sandstones and quartzites have also been identified in a wide variety of environments and generally termed pseudokarst. These include large bedrock pinnacles and towers, caves, corridors, grikes, solution basins and runnels, and even silica speleothems. Quartzites and quartz sandstones have been held to be amongst the most chemically resistant of rocks, but the similarity, both in morphology and genetic process of many landforms developed from them to features of known solutional origin on limestone, has prompted some authors to refer to these quartzose landforms as true karst. The most detailed studies of quartzose karst landforms have been in present-day tropical regions, or areas believed to have been tropical in the geologically recent past. This concentration of research in hot-wet areas, allied with the long held assertion of the insolubility of silica, especially quartz, has led to a belief that tropical climatic conditions are necessary for karstic solution of these rocks. However, the existence of quartzose karst landforms in temperate and even sub-polar latitudes, especially where there is no evidence of prior tropical conditions, suggests that the requirement of tropical weathering is no longer tenable. The reports of these quartzose solutional landforms are widely scattered through the geomorphological and geological literature, but a comprehensive world-wide review of the range of solutional landforms on quartzose rocks has not previously been published. Because of the increasing awareness in this karst type such a summary is sorely overdue.

Wray, R. A. L.

1997-05-01

45

Weather  

NSDL National Science Digital Library

This is a first grade weather unit. SEASONS Fall Winter Build a Snowman Spring Summer What things determine and effect the weather? Cloud Precipitation Sunshine Temperature Visibility Wind Direction Wind Force WEATHER VIDEOS Tornado Hurricane Hail Lightning FUN AND GAMES Dress the Bear for the Weather The Great Weather Race Game Weather coloring books for kids ...

Stearns, Ms.

2008-10-25

46

Weather  

NSDL National Science Digital Library

Have you ever wondered how the weather man, or meteorolgist, on TV knows what to say about tomorrow\\'s weather? It\\'s because they have certain tools that they use that help them predict what the weather will be. Throughout this school year you are going to be making tools and predicting weather just like a meterorologist! Task You are going to be weather forcasters! You are going to record and track weather patterns throughout the year. You will also use weather tools to make predictions about the weather like real weather forecasters! The Process 1. First we need to learn a little bit about weather so ...

Williams, Ms.

2005-10-25

47

Weathering  

NSDL National Science Digital Library

This course handout covers the processes and effects of weathering. The purpose of this handout is to contrast weathering and erosion, contrast and discuss chemical and mechanical weathering, list the products resulting from the chemical weathering of igneous rocks, and list and discuss the factors that influence the type and rate of rock weathering. Many photographs accompany this summary which depict weathered landscapes. Links are provided to the online Physical Geology resources at Georgia Perimeter College.

Gore, Pamela

1995-08-29

48

The Southern Ocean silicon trap: Data-constrained estimates of regenerated silicic acid, trapping efficiencies, and global transport paths  

NASA Astrophysics Data System (ADS)

We analyze an optimized model of the global silicon cycle embedded in a data-assimilated steady ocean circulation. Biological uptake is modeled by conditionally restoring silicic acid in the euphotic zone to observed concentrations where the modeled concentrations exceed the observational climatology. An equivalent linear model is formulated to which Green-function-based transport diagnostics are applied. We find that the models' opal export through 133 m depth is 166 ± 24 Tmol Si/yr, with the Southern Ocean (SO) providing ˜70% of this export, ˜50% of which dissolves above 2000 m depth. The global-scale gradients of the opal dissolution rate are primarily meridional, while the global-scale gradients of phosphate remineralization are primarily vertical. The mean depth of the temperature-dependent silicic-acid regeneration reaches 2300 m in the SO, compared to 600 m for phosphate remineralization. Silicic acid is stripped out of the euphotic zone far more efficiently than phosphate, with only (34 ± 5)% of the global silicic-acid inventory being preformed, compared to (61 ± 7)% for phosphate. Subantarctic and tropical waters contribute most of the ocean's regenerated silicic acid, while Antarctic waters provide most of the preformed silicic acid. About half of the global silicic-acid inventory is trapped in transport paths connecting successive SO utilizations, with silicic acid last utilized in the SO having only a (5 ± 2)% chance of being next utilized outside the SO. This trapping depletes subantarctic mode waters of silicic acid relative to phosphate, which has a (44 ± 2)% probability of escaping successive SO utilization.

Holzer, Mark; Primeau, François W.; DeVries, Timothy; Matear, Richard

2014-01-01

49

Timing of Neoproterozoic glaciations linked to transport-limited global weathering  

NASA Astrophysics Data System (ADS)

The Earth underwent several snowball glaciations between 1,000 and 542 million years ago. The termination of these glaciations is thought to have been triggered by the accumulation of volcanic CO2 in the atmosphere over millions of years. Subsequent high temperatures and loss of continental ice would increase silicate weathering and in turn draw down atmospheric CO2 (ref. ). Estimates of the post-snowball weathering rate indicate that equilibrium between CO2 input and removal would be restored within several million years , potentially triggering a new glaciation. However the transition between deglaciation and the onset a new glaciation was on the order of 107 years. Over long timescales, the availability of fresh rock can become a limiting factor for silicate weathering rates. Here we show that when this transport-determined limitation is incorporated into the COPSE biogeochemical model, the stabilization time is substantially longer, >107 years. When we include a simple ice-albedo feedback, the model produces greenhouse-icehouse oscillations on this timescale that are compatible with observations. Our simulations also indicate positive carbon isotope excursions and an increased flux of oxygen to the atmosphere during interglacials, both of which are consistent with the geological record. We conclude that the long gaps between snowball glaciations can be explained by limitations on silicate weathering rates.

Mills, Benjamin; Watson, Andrew J.; Goldblatt, Colin; Boyle, Richard; Lenton, Timothy M.

2011-12-01

50

Shaken and Stirred: A Combined Reaction-Diffusion and Random Rate Model for the Temporal Evolution and Earthquake-induced Hydrodynamics of Silicate Mineral Weathering  

NASA Astrophysics Data System (ADS)

The time dependency of silicate mineral weathering has been explored in the literature in terms of processes and features that are intrinsic and extrinsic to the mineral [1]. However, although the advent of sophisticated reactive transport models has allowed for coupling increasingly complex reaction and transport processes [2,3], a simple and fundamental understanding of the temporal evolution of weathering is lacking. Here, we propose that a purely deterministic approach may not be sufficient given the inherent differences in reactivity over space and time. Therefore, we explore how a combined reaction-diffusion and random rate model - informed by a stochastic distribution of weathering rates K (T-1) - might be able to explain not only the temporal evolution but also the hydrodynamics of weathering during earthquakes; the latter being purportedly described by time-dependent property permeability (L2). Preliminary model results show that (1) an increase in dimensionless quantity ?rp, where ? is the diffusion length (L-1) and rp is the distance between pores (L), leads to a decrease in minimum reaction rate with time from the relation Kmin ? e-?rp/rp ; (2) at a given porosity, a time-dependent decrease in reactivity arises as permeability decreases due to decreasing pore size (and therefore increasing rp), which in turn may be related to the time-dependent feedback between dissolution and precipitation; (3) while permeability is lower in older soils, transient stresses as during earthquakes [4], may induce more efficient "declogging" of pores in these soils than in younger soils due to higher hydrodynamic viscous shear stress, thereby, resulting in a coseismic change in stream discharge Q; and (4) subsequent weathering beyond t~Kmin-1 exhibits a fall in rates, marking the cessation of logarithmic decay possibly due to dissolution-precipitation feedback. [1] White and Brantley (2003), Chem. Geol. 202, 479. [2] Lichtner P.C. (1996), Mineralogical Society of America, 1-81. [3] Maher K., Steefel C.I., White A.F. and Stonestrom D.A. (2009), Geochim. Cosmochim. Acta 73, 2804-2831. [4] Manga M., Beresnev I., Brodsky E. E., Elkhoury J. E., Elsworth D., Ingebritsen S. E., Mays D.C., and Wang C.Y. (2012), Rev. Geophys., 50, RG2004. (A) The evolution of reaction rates K(y-1) derived from published weathering rates as a first-order process. A similar scaling exponent was reported in the decay of marine organic carbon by Middelburg et al. (1993), K(t)=0.21t-0.99; and Rothman and Forney (2007) K(t)=0.23t-1. (B) Plot of global permeability (Gleeson et al. 2011) across a wide range of consolidated and loose hydrolithologies (different symbols) versus corresponding weathering rates from the reaction-diffusion model. Broken line approximates an inflection point (?log10 k -14.5 m2) based on the logistic curve fit (red line). Range of predicted reaction rates agree well with rates derived from the field.

Evaristo, J. A.; Willenbring, J.

2013-12-01

51

Do fair weather regions contribute to the global circuit support?  

NASA Astrophysics Data System (ADS)

The role of different generators (thunderstorm clouds, mesoscale convective systems, electrified shower clouds etc.) in the maintaining the ionospheric potential (IP) of the global electric circuit (GEC) and its variation is still insufficiently understood. This paper considers possible approaches to the modeling of GEC generators with particular focus on the planetary boundary layer (PBL), or Austausch, generator, operating in the fair weather regions. It is well known that turbulent convection leads to intensive mixing of charged particles in the PBL and, consequently, to the generation of the vertical electric current. As a rule, this current is directed upward if the positive charge is accumulated near the Earth's surface particularly due to the electrode effect. There is still a great uncertainty concerning the contribution of the PBL generator into the global circuit. This is not only for a lack of data, but also due to the difficulties of theory: the intensity of the generator depends upon the IP, so the search for its contribution into the GEC requires solving a self-consistent problem. We suggest an analytical approach for the calculation of the IP induced by the given electric currents in the atmosphere. The obtained expressions and numerical calculations show that convection amplifies the contributions of thunderstorm/shower-cloud sources, while the value of this amplification varies likely from 10 to 20% depending mainly on the square occupied by intensive convection and the mean thickness of the PBL. It is important that the diurnal motion of the convection area on the Earth's surface may cause regular variations into the IP diurnal variation (reflected in the Carnegie curve), superimposed with the thunderstorm/shower-cloud contributions. It is suggested that the contribution of PBL generator into the GEC potential maximizes when the Pacific ocean surface is sunlit because at this time both conditions of its operation are satisfied: the PBL is unstable; the electrode effect forms over the maximum square because over the land surface this effect is often not developed due to radioactive emanations.

Mareev, Evgeny

2014-05-01

52

Weather  

NSDL National Science Digital Library

The National Oceanic and Atmospheric Administration (NOAA) provides these two Websites on weather. The first site serves as a major hub for information related to weather, with links to primary data sources, forecasts, maps, images (such as the latest satellite imagery for North America), and a wealth of other data, including space weather. Researchers will also find links to national weather research centers and other related agencies.

53

Weather  

NSDL National Science Digital Library

What are the different types of weather? In this project you will compare different types of weather by drawing pictures and making it into a flip book. First you will begin by learning about the different types of weather. Read about each topic. Then get together with your partner and draw a picture of each type of weather. 1. Thunder storm Thunder storm Thunder storm Kids 2. Lightning Lightning Lightning picture 3. Tornado Tornadoes Tornado Kids 4. ...

Jennie, Miss

2009-10-22

54

Weather  

NSDL National Science Digital Library

You will learn how to describe and observe changes in weather patterns by completing the following activities. The students will record and report changes in weather on their data sheet. The Process: Read the information on How Air Pressure Affects You. In this article you will see the term barometer. Write its definition. Now look over Weather Facts. Now go to Investigate Climate Conditions and use the weather maker to observe the effects of certain changes. Answer the questions: How much of a change in temperature is needed to make it ...

Lauren, Ms.

2010-11-17

55

Atmospheric and oceanographic research review, 1978. [global weather, ocean/air interactions, and climate  

NASA Technical Reports Server (NTRS)

Research activities related to global weather, ocean/air interactions, and climate are reported. The global weather research is aimed at improving the assimilation of satellite-derived data in weather forecast models, developing analysis/forecast models that can more fully utilize satellite data, and developing new measures of forecast skill to properly assess the impact of satellite data on weather forecasting. The oceanographic research goal is to understand and model the processes that determine the general circulation of the oceans, focusing on those processes that affect sea surface temperature and oceanic heat storage, which are the oceanographic variables with the greatest influence on climate. The climate research objective is to support the development and effective utilization of space-acquired data systems in climate forecast models and to conduct sensitivity studies to determine the affect of lower boundary conditions on climate and predictability studies to determine which global climate features can be modeled either deterministically or statistically.

1978-01-01

56

Basalt weathering laws and the impact of basalt weathering on the global carbon cycle  

Microsoft Academic Search

This study attempts to characterise the chemical weathering of basalts and to quantify the flux of carbon transferred from the atmosphere to the ocean during this major process at the surface of the Earth. To this aim, we have compiled different published chemical compositions of small rivers draining basalts. Basaltic river waters are characterised by relatively high Na-normalized molar ratios

Céline Dessert; Bernard Dupresupasu; Jérôme Gaillardet; Louis M. François; Claude J. Allègre

2003-01-01

57

Stormy Weather: 101 Solutions to Global Climate Change.  

ERIC Educational Resources Information Center

This document presents 101 solutions to global climate change. These solutions are actions that are well suited to every level of society. This book creates awareness about global climate change. The history of Earth and the greenhouse effect are discussed, and explanations and solutions to global climate change are provided including traveling…

Dauncey, Guy

58

Hydrologic regulation of chemical weathering and the geologic carbon cycle.  

PubMed

Earth's temperature is thought to be regulated by a negative feedback between atmospheric CO2 levels and chemical weathering of silicate rocks that operates over million-year time scales. To explain variations in the strength of the weathering feedback, we present a model for silicate weathering that regulates climatic and tectonic forcing through hydrologic processes and imposes a thermodynamic limit on weathering fluxes, based on the physical and chemical properties of river basins. Climate regulation by silicate weathering is thus strongest when global topography is elevated, similar to the situation today, and lowest when global topography is more subdued, allowing planetary temperatures to vary depending on the global distribution of topography and mountain belts, even in the absence of appreciable changes in CO2 degassing rates. PMID:24625927

Maher, K; Chamberlain, C P

2014-03-28

59

Forecasting short-term changes in the earth's rotation using global numerical weather prediction models  

Microsoft Academic Search

The use of global weather-prediction models in predicting changes in the earth's rotation is examined with reference to the main indicators of rotational variation. The calculation of atmospheric angular momentum (AAM) requires global wind and pressure data up to the highest atmospheric altitudes, although limitations are still present in the AAM and rotation calculations. AAM forecasts are found to be

Raymond Hide

1990-01-01

60

Weather.  

ERIC Educational Resources Information Center

This subject guide to weather resources includes Web sites, CD-ROMs and software, videos, books, audios, magazines, and professional resources. Related disciplines are indicated, age levels are specified, and a student activity is included. (LRW)

Web Feet K-8, 2000

2000-01-01

61

Weathering  

Microsoft Academic Search

In the natural environment, weathering and breakdown of stone is an accepted part of long-term landscape development but the\\u000a same acceptance of change and deterioration is not extended to stone used in construction especially when such deterioration\\u000a affects historically and\\/or culturally important structures. The value of an integrative approach to improve understanding\\u000a of weathering and failure of building stone is

P. A. Warke; J. McKinley; B. J. Smith

62

Seafloor weathering controls on atmospheric CO{sub 2} and global climate  

SciTech Connect

Alteration of surficial marine basalts at low temperatures (<40{degrees}C) is a potentially important sink for atmospheric CO{sub 2} over geologic time. Petrologic analyses, thermodynamic calculations, and experimental weathering results point to extensive Ca leaching and consumption of marine CO{sub 2} during alteration. Basalt weathering in seawater-like solutions is sensitive to temperature. The activation energy for initial basalt weathering in seawater is 41-65 U kJ mol{sup -1}. If seafloor weathering temperatures are set by deep ocean fluids under high fluid to rock ratios the feedback between weathering and atmospheric CO{sub 2} is indirect, but sizeable. If the bulk of seafloor weathering occurs in the presence of low-temperature hydrothermal fluids, the weathering feedback depends on the linkage between spreading rates and heat flow. In either case, the primary linkage between seafloor weathering and the global carbon cycle appears to be thermal as opposed to chemical. 81 refs., 4 figs., 2 tabs.

Brady, P.V. [Sandia National Labs., Albuquerque, NM (United States)] [Sandia National Labs., Albuquerque, NM (United States); Gislason, S.R. [Univ. of Iceland, Reykjavik (Iceland)] [Univ. of Iceland, Reykjavik (Iceland)

1997-03-01

63

Weather  

NSDL National Science Digital Library

In the project you will learn about thunderstorms and tornadoes and play a weather matching game. What exactly are thunderstorms and tornadoes? Use your T- chart to explain some facts about a thunderstorm and a tornado as we review each. T-Chart Begin by reviewing what a thunderstorm is and how they form. Thunderstorm information What is a thunderstorm? What are thunderstorms most likely to occur? What causes thunder? Next review what a tornado ...

Caitlin, Ms.

2009-10-21

64

High-Silica Rock Coatings on Mars: Constraining Secondary Silicate Mineralogy and Chemical Weathering Processes on Mars  

Microsoft Academic Search

Thermal Emission Spectrometer (TES) data have been fundamental to understanding Martian surface mineralogy. These data, however, require careful modeling based on laboratory spectroscopic measurements, and modeling of some minerals for Mars has been equivocal. Due to high degrees of spectral similarity, it is difficult to distinguishing silicate glass, clay minerals, zeolites, palagonitized glass, and other secondary products such as amorphous

M. D. Kraft; J. R. Michalski; T. G. Sharp

2003-01-01

65

Characterizing englacial and subglacial weathering processes in a silicate-carbonate system at Robertson Glacier, Canada: Combining field measurements and remote sensing  

NASA Astrophysics Data System (ADS)

Geologic weathering processes in cold environments, especially processes acting on subglacial and englacial sediments and rocks, are not well characterized due to the difficulty of accessing these environments. However, subglacial and englacial weathering of geologic materials contributes to the solute flux in meltwater and provides a potential source of energy to chemotrophic microbes, and is thus an important component to understand. In this study, we characterize the weathering products present in a glaciated silicate-carbonate system using infrared spectroscopy, x-ray diffraction, and geochemical analyses. We use Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) data to determine whether glacial weathering products can be detected from remotely detected infrared spectra. The major goals of the project are to quantify weathering inputs to the glacial energy budget, and to link in situ sampling with remote sensing capabilities. Robertson Glacier, Alberta, Canada (115°20'W, 50°44'N) provides an excellent field site for this technique as it is accessible, and its retreating stage allows sampling of fresh subglacial and englacial sediments. This site is also of great significance to microbiology studies due to the recent detection of methanogens in the local subglacial till. Samples of glacially altered rock and sediments were collected on a downstream transect of the glacier in September 2011. Infrared laboratory spectroscopy and x-ray diffraction were used to determine the composition and abundance of minerals present. Infrared imagery of the region was collected at the time of sampling with the ASTER satellite instrument. Geochemical data were also collected at each location, and ice and water samples were analyzed for major and minor elements. pH values decreased in the downstream direction, and Ca+2 and SO4-2 in solution increased downstream. This is initially consistent with earlier studies of similar systems; however, the majority of the observed changes in concentrations seem to occur immediately at the supraglacial-subglacial interface. Change in concentrations decreases downstream of the glacier terminus. Our initial conclusion is that the majority of the weathering seems to be occurring at the ice-rock interface rather than in the outwash stream. Initial results from both laboratory and ASTER data indicate the presence of weathering products. A general trend of decreasing carbonate abundances with elevation (i.e. residence time in ice) is observed, which is consistent with the increasing Ca+2 ion concentrations towards the terminus. More mineralogical work, such as thin section analyses, is ongoing in order to refine the types of weathering products present in the system.

Rutledge, A. M.; Christensen, P. R.

2012-12-01

66

Global Muon Detector Network Used for Space Weather Applications  

NASA Astrophysics Data System (ADS)

In this work, we summarize the development and current status of the Global Muon Detector Network (GMDN). The GMDN started in 1992 with only two muon detectors. It has consisted of four detectors since the Kuwait-city muon hodoscope detector was installed in March 2006. The present network has a total of 60 directional channels with an improved coverage of the sunward Interplanetary Magnetic Field (IMF) orientation, making it possible to continuously monitor cosmic ray precursors of geomagnetic storms. The data analysis methods developed also permit precise calculation of the three dimensional cosmic ray anisotropy on an hourly basis free from the atmospheric temperature effect and analysis of the cosmic ray precursors free from the diurnal anisotropy of the cosmic ray intensity.

Rockenbach, M.; Dal Lago, A.; Schuch, N. J.; Munakata, K.; Kuwabara, T.; Oliveira, A. G.; Echer, E.; Braga, C. R.; Mendonça, R. R. S.; Kato, C.; Kozai, M.; Tokumaru, M.; Bieber, J. W.; Evenson, P.; Duldig, M. L.; Humble, J. E.; Al Jassar, H. K.; Sharma, M. M.; Sabbah, I.

2014-05-01

67

System implementation for US Air Force Global Theater Weather Analysis and Prediction System (GTWAPS)  

SciTech Connect

The Global Theater Weather Analysis and Prediction System (GTWAPS) is intended to provide war fighters and decision makers with timely, accurate, and tailored meteorological and oceanographic (METOC) information to enhance effective employment of battlefield forces. Of critical importance to providing METOC theater information is the generation of meteorological parameters produced by numerical prediction models and application software at the Air Force Global Weather Central (AFGWC), Offutt Air Force Base, Nebraska. Ultimately, application-derived data will be produced by the regional Joint METOC Forecast Units and by the deployed teams within a theater. The USAF Air Staff contracted with Argonne National Laboratory (ANL) for assistance in defining a hardware and software solution using off-the-shelf technology that would give the USAF the flexibility of testing various meteorological models and the ability to use the system within their daily operational constraints.

Simunich, K.L.; Pinkerton, S.C.; Michalakes, J.G.; Christiansen, J.H.

1997-03-01

68

44/40Ca and 87Sr/86Sr isotopes as tracers of silicate weathering in small catchments of the Massif Central, France  

NASA Astrophysics Data System (ADS)

We present calcium stable isotope and strontium radiogenic isotope data for soils and sediments developed on volcanic and igneous rocks forming small catchments in the Massif Central (France). Measurements of 44/40Ca isotope ratios (44/40Ca measured by the double spike method on TIMS and normalized to the value for seawater Ca in delta units) in rocks, sediments and soils from silicate catchments (e.g. granite and basalts) together with 87Sr/86Sr isotope ratios permit an examination of the relationships of these isotope systematics during weathering of silicate rocks. We have analysed the granite, weathered granite (arene) and saprolite, sediment and soil overlying the granite on one hand and the basanite, sediment and soil overlying the basanite on the other. The main bedrock in the volcanic zone (e.g. Allanche catchment) is 11 to 2.5 Ma basanite (nephelinitic to leucitic basalts) having SiO2 between 41-45 wt. %, Na2O + K2O <5%, modal or normative nepheline or leucite and a ground mass of clinopyroxene and plagioclase. Surrounding rocks are feldspathic basalts having SiO2 between 46-49 wt. %, Na2O + K2O <5%, normative nepheline, hyperstene and olivine, with plagioclase as the main crystalline phase. The granite massif (e.g. Margeride, 332 ± 12Ma) consists of light and dark facies as a result of the fractional crystallisation of a crustal magma in a sub-horizontal laccolith, with leucogranites dated at 298±2 Ma intruding this granite. The average mineral composition is 37% quartz, 30% oligoclase, 23% K-feldspar and 10% biotite (light facies) and 31% quartz, 30% andesine, 20% K-feldspar and 19% biotite (dark facies). Sr isotope ratios in the arene, sediment and soil diverge strongly from those in the granite bedrock and are positively correlated with Rb/Sr ratios. The 87Sr/86Sr and Rb/Sr ratios both increase from the whole rock to the arene, reflecting the weathering of low 87Sr/86Sr, low-Rb/Sr minerals such as plagioclase and apatite. Sediments collected on a river bank have 87Sr/86Sr ratios greater than that of the arene with values increasing in the sediment from the surface down to soil. The 87Sr/86Sr vs. Rb/Sr variation observed in the volcanic area likewise confirms the weathering of low 87Sr/86Sr, low Rb/Sr phases in the bedrock, and there is a linear increase in 87Sr/86Sr and Rb/Sr ratios from those in the sediment up to the values observed in the soils. In the volcanic area, the basanite bedrock has 44/40Ca = -0.94 ± 0.05‰ (n = 7), while the soils and sediments have 44/40Ca of -0.75 to -1.13‰ and -0.79 to -1.01‰, respectively. These results suggest that Ca isotopes are not strongly fractionated during weathering of the basalt. The granite whole-rock has 44/40Ca of -1.29‰, while the soil and sediments have 44/40Ca of -1.93 to -2.07‰ and -1.98 to -2.81‰, respectively, with values decreasing as the Ca content decreases. The 44/40Ca ratios of arene, soil and sediment are similar to or less than that of K- feldspar, reflecting complete loss of the relatively heavy Ca from plagioclase and apatite during weathering. Comparison of the 44/40Ca and 87Sr/86Sr ratios further revealed the role of mineralogical assemblage in sediments and soils, particularly for the lesser 44/40Ca - greater 87Sr/86Sr samples, when compared to the bedrock.

Négrel, Philippe; Guerrot, Catherine; Millot, Romain; Petelet-Giraud, Emmanuelle; Bullen, Thomas

2013-04-01

69

Assimilation of global positioning system radio occultation measurements into numerical weather forecast systems  

NASA Astrophysics Data System (ADS)

2004 marks the centennial of Bjerknes' conceptual solution to the problem of weather forecasting, based on the application of physical and mechanical laws to a set of initial conditions. Today many satellites observe our atmosphere to help provide these initial conditions to numerical weather forecast systems. However, there is still considerable room for improvement when it comes to weather forecasts, namely by better constraining the atmospheric initial conditions through more frequent and more accurate atmospheric observations. The radio occultation (RO) technique which observes the atmosphere from the side (instead of from above, like today's numerous weather satellites) was used for decades to study planetary atmospheres before it was finally used observe our atmosphere. The level of accuracy required in order to make RO competitive with or superior to other techniques already observing the atmosphere was achieved with the advent of the Global Positioning System (CPS) and later with advanced CPS receiver technology. We demonstrate here that useful one-dimensional (1D) vertical atmospheric temperature information can be retrieved from GPS RO refractive index measurements. We develop a first-generation system capable of retrieving that information from real CPS RO refractive index measurements, and assimilating it into a numerical weather forecast system. Resulting five day weather forecasts issued with that system show improved accuracy in the Northern hemisphere and degraded accuracy in the Southern hemisphere. Analyzing data from late CPS RO missions onboard CHAMP and SAC-C satellites, we find that improved receiver technology and processing techniques yield more CPS RO data and of better quality. We develop a two-dimensional (2D) ray-tracing iterative procedure to simulate CPS RO measurements from the three-dimensional (3D) atmospheric representation provided by a numerical weather forecast system. We demonstrate that the 2D ray-tracing results agree better with the CHAMP and SAC-C measurements than the 1D approach used in our first-generation system. In order to render the use of this type of modelling possible under the stringent time constraints of operational numerical weather prediction centers, we propose a new operator called the Fast Atmospheric Refractivity Gradient Operator (FARGO). FARGO is shown to be 250 times faster and nearly as efficient as 2D ray-tracing in fitting real observations. The work presented here will serve to implement a second-generation assimilation system of CPS RO data into numerical weather forecast systems. Also, the approach used in FARGO can be extended to simulate other refraction measurements which suffer from horizontal inhomogeneities in the Earth's lower troposphere.

Poli, Paul

70

Death and Death Rates Due to Extreme Weather Events: Global and U.S. Trends, 1900-2004  

Microsoft Academic Search

Despite the recent spate of deadly extreme weather events such as the 2003 European heat wave and the hurricanes of 2004 and 2005, aggregate mortality and mortality rates due to extreme weather events are generally lower today than they used to be. Globally, mortality and mortality rates have declined by 95 percent or more since the 1920s. The largest improvements

Indur M. Goklany

71

The analysis sensitivity to tropical winds from the Global Weather Experiment  

NASA Technical Reports Server (NTRS)

The global scale divergent and rotational flow components of the Global Weather Experiment (GWE) are diagnosed from three different analyses of the data. The rotational flow shows closer agreement between the analyses than does the divergent flow. Although the major outflow and inflow centers are similarly placed in all analyses, the global kinetic energy of the divergent wind varies by about a factor of 2 between different analyses while the global kinetic energy of the rotational wind varies by only about 10 percent between the analyses. A series of real data assimilation experiments has been performed with the GLA general circulation model using different amounts of tropical wind data during the First Special Observing Period of the Global Weather Experiment. In exeriment 1, all available tropical wind data were used; in the second experiment, tropical wind data were suppressed; while, in the third and fourth experiments, only tropical wind data with westerly and easterly components, respectively, were assimilated. The rotational wind appears to be more sensitive to the presence or absence of tropical wind data than the divergent wind. It appears that the model, given only extratropical observations, generates excessively strong upper tropospheric westerlies. These biases are sufficiently pronounced to amplify the globally integrated rotational flow kinetic energy by about 10 percent and the global divergent flow kinetic energy by about a factor of 2. Including only easterly wind data in the tropics is more effective in controlling the model error than including only westerly wind data. This conclusion is especially noteworthy because approximately twice as many upper tropospheric westerly winds were available in these cases as easterly winds.

Paegle, J.; Paegle, J. N.; Baker, W. E.

1986-01-01

72

The data systems tests - The final phase. [for Global Weather Experiment  

NASA Technical Reports Server (NTRS)

The U.S.A. has conducted a series of data systems tests (DSTs) as a precursor to its participation in FGGE, the Global Weather Experiment. The paper briefly describes the impact those tests have had on the FGGE observing system and on the data management plans. In particular, the final phase of the DST programs is described, wherein a number of investigators have been selected to work with the DST data sets in research studies directed toward the GARP objectives. Thus, an important first step has been taken in providing feedback to the potential FGGE research community.

Greaves, J. R.

1979-01-01

73

Long Range Weather Prediction III: Miniaturized Distributed Sensors for Global Atmospheric Measurements  

SciTech Connect

We continue consideration of ways-and-means for creating, in an evolutionary, ever-more-powerful manner, a continually-updated data-base of salient atmospheric properties sufficient for finite differenced integration-based, high-fidelity weather prediction over intervals of 2-3 weeks, leveraging the 10{sup 14} FLOPS digital computing systems now coming into existence. A constellation comprised of 10{sup 6}-10{sup 9} small atmospheric sampling systems--high-tech superpressure balloons carrying early 21st century semiconductor devices, drifting with the local winds over the meteorological spectrum of pressure-altitudes--that assays all portions of the troposphere and lower stratosphere remains the central feature of the proposed system. We suggest that these devices should be active-signaling, rather than passive-transponding, as we had previously proposed only for the ground- and aquatic-situated sensors of this system. Instead of periodic interrogation of the intra-atmospheric transponder population by a constellation of sophisticated small satellites in low Earth orbit, we now propose to retrieve information from the instrumented balloon constellation by existing satellite telephony systems, acting as cellular tower-nodes in a global cellular telephony system whose ''user-set'' is the atmospheric-sampling and surface-level monitoring constellations. We thereby leverage the huge investment in cellular (satellite) telephony and GPS technologies, with large technical and economic gains. This proposal minimizes sponsor forward commitment along its entire programmatic trajectory, and moreover may return data of weather-predictive value soon after field activities commence. We emphasize its high near-term value for making better mesoscale, relatively short-term weather predictions with computing-intensive means, and its great long-term utility in enhancing the meteorological basis for global change predictive studies. We again note that adverse impacts of weather involve continuing costs of the order of 1% of GDP, a large fraction of which could be retrieved if high-fidelity predictions of two weeks forward applicability were available. These {approx}$10{sup 2} B annual savings dwarf the <$1 B costs of operating a rational, long-range weather prediction system of the type proposed.

Teller, E; Leith, C; Canavan, G; Wood, L

2001-11-13

74

Recovery of Global Surface Weather Observations for Historical Reanalyses and International Users  

NASA Astrophysics Data System (ADS)

Third International Atmospheric Circulation Reconstructions Over the Earth Initiative Workshop: Reanalysis and Applications; Baltimore, Maryland, 3-5 November 2010 ; The third Atmospheric Circulation Reconstructions over the Earth (ACRE) workshop advanced the goals of the international ACRE initiative (http://www.met-acre.org/) to undertake and facilitate the recovery of instrumental terrestrial and marine global surface weather observations underpinning global weather reconstructions and reanalyses spanning the past 200-250 years (http://reanalyses.org). The workshop improved integration of the 35-40 ACRE-linked international scientific projects, institutions, and organizations working toward these ends. The meeting highlighted the broad array and international usage of ACRE-facilitated data sets and reanalysis: the International Surface Pressure Databank (ISPD; http://dss.ucar.edu/datasets/ds132.0/), the International Comprehensive Ocean-Atmosphere Data Set (http:/icoads.noaa.gov/ICOADS;), and the 20th Century Reanalysis (20CR; http://www.esrl.noaa.gov/psd/data/20thC_Rean/). The need for more data recovery for all regions of the globe during the nineteenth and early twentieth centuries was emphasized. Many regional efforts for such recovery are under way. The Arctic and maritime regions were highlighted as particular areas needing attention. As a result of the meeting, connections with existing projects were made and new efforts were started to address these needs.

Allan, Rob; Compo, Gil; Carton, Jim

2011-05-01

75

Magnesium isotope fractionation between brucite [Mg(OH)2] and Mg aqueous species: Implications for silicate weathering and biogeochemical processes  

NASA Astrophysics Data System (ADS)

Brucite, with its octahedral structure, has a lattice configuration that is similar to the Mg-bearing octahedral layers in phyllosilicates. Understanding stable Mg isotope fractionation between brucite and aqueous solution therefore bears on interpretation of Mg isotope data in natural weathering systems. In this study, we experimentally determined Mg isotope fractionation between brucite and two Mg aqueous species, the free Mg aquo ion ([Mg(OH2)6]2+) and EDTA-bonded Mg (Mg-EDTA2-). Results from recrystallization and brucite synthesis experiments suggest mild preferential partitioning of light Mg isotopes into brucite compared to Mg aquo ions at low temperatures, where measured ?Mgbrucite-Mg26 fractionation increased from ca. -0.3‰ at 7?°C, to ca. -0.2‰ at 22?°C, to ca. 0‰ at 40?°C. MgO hydrolysis experiments in EDTA-bearing solutions suggest that the ?Mgbrucite-Mg-EDTA26 fractionation is ?+2.0‰ at 22?°C, indicating that light Mg isotopes strongly partition into Mg-EDTA complex relative to brucite, as well as relative to Mg aquo ions. Magnesium atoms in brucite, Mg aquo ions, and Mg-EDTA complexes are all octahedrally coordinated, and the measured Mg isotope fractionations correlate with average bond lengths for Mg. Aqueous Mg ions have the shortest bond length among the three phases, and enrich heavy Mg isotopes relative to brucite and Mg-EDTA. In contrast, Mg-EDTA has the longest average bond length for Mg, and enriches light Mg isotopes relative to Mg aquo ions and brucite; the relatively long Mg-EDTA bond suggests that organically bound Mg may commonly have low 26Mg/24Mg ratios, which may explain proposed "vital" effects for stable Mg isotopes. Such relations between bond length and Mg isotope fractionation could be extended to other phyllosilicates such as serpentine- and clay-group minerals where Mg is also octahedrally coordinated.

Li, Weiqiang; Beard, Brian L.; Li, Chengxiang; Johnson, Clark M.

2014-05-01

76

Space weathering of silicate regoliths with various FeO contents: New insights from laser irradiation experiments and theoretical spectral simulations  

NASA Astrophysics Data System (ADS)

To investigate effects of micrometeorite bombardment on optical spectra and composition of planetary and asteroid regoliths with low Fe contents, we irradiated samples of a Fe-poor plagioclase feldspar (andesine-labradorite) using a nanosecond pulsed laser. We measured reflectance spectra of irradiated and non-irradiated areas of the samples (pressed pellets) between 0.5 and 18 ?m and performed SEM/EDS and TEM studies of the samples. Bulk FeO content of 0.72 wt.% in the samples is comparable, for example, to FeO content in silicates on the surface of Mercury, that was recently mapped by NASA's MESSENGER mission and will be spectrally mapped by remote sensing instruments MERTIS and SYMBIO-SYS on board the ESA BepiColombo spacecraft. We also employed theoretical spectral modeling to characterize optical alteration caused by formation of nano- and submicrometer Fe0 inclusions within space-weathered surface layers and grain rims of a Fe-poor regolith. The laser-irradiated surface layer of plagioclase reveals significant melting, while reflectance spectra show mild darkening and reddening in the visible and near-infrared (VNIR). Our spectral modeling indicates that the optical changes observed in the visible require reduction of bulk FeO (including Fe from mineral impurities found in the sample) and formation of nanophase (np) Fe0 within the glassy surface layer. A vapor deposit, if present, is optically too thin to contribute to optical modification of the investigated samples or to cause space weathering-induced optical alteration of Fe-poor regoliths in general. Due to low thickness of vapor deposits, npFe0 formation in the latter can cause darkening and reddening only for a regolith with rather high bulk Fe content. Our calculations show that only a fraction of bulk Fe is likely to be converted to npFe0 in nanosecond laser irradiation experiments and probably in natural regolith layers modified by space weathering. The previously reported differences in response of different minerals to laser irradiation, and probably to space weathering-induced heating are likely controlled by their differences in electrical conductivities and melting points. For a given mineral grain, its susceptibility to melting/vaporization is also affected by electric conductivities of adjacent grains of other minerals in the regolith. Published nanosecond laser irradiation experiments simulate optical alteration of immature regoliths, since only the uppermost surface layer of an irradiated pellet is subject to heating. According to our calculations, if regolith particles due to impact-induced turnover are mantled with npFe0-bearing rims of the same thickness, then even low contents of Fe similar to our sample or Mercury' surface can cause significant darkening and reddening, provided a melt layer, rather than a thin vapor deposit is involved into npFe0 formation. All spectral effects observed in the thermal infrared (TIR) after irradiation of our feldspar sample are likely to be associated with textural changes. We expect that mineralogical interpretation of the BepiColombo MERTIS infrared spectra of Mercury between 7 and 17 ?m will be influenced mostly by textural effects (porosity, comminution) and impact glass formation rather than formation of npFe0 inclusions.

Moroz, Lyuba V.; Starukhina, Larissa V.; Rout, Surya Snata; Sasaki, Sho; Helbert, Jörn; Baither, Dietmar; Bischoff, Addi; Hiesinger, Harald

2014-06-01

77

Impacts of increasing the aerosol complexity in the Met Office global numerical weather prediction model  

NASA Astrophysics Data System (ADS)

The inclusion of the direct and indirect radiative effects of aerosols in high-resolution global numerical weather prediction (NWP) models is being increasingly recognised as important for the improved accuracy of short-range weather forecasts. In this study the impacts of increasing the aerosol complexity in the global NWP configuration of the Met Office Unified Model (MetUM) are investigated. A hierarchy of aerosol representations are evaluated including three-dimensional monthly mean speciated aerosol climatologies, fully prognostic aerosols modelled using the CLASSIC aerosol scheme and finally, initialised aerosols using assimilated aerosol fields from the GEMS project. The prognostic aerosol schemes are better able to predict the temporal and spatial variation of atmospheric aerosol optical depth, which is particularly important in cases of large sporadic aerosol events such as large dust storms or forest fires. Including the direct effect of aerosols improves model biases in outgoing long-wave radiation over West Africa due to a better representation of dust. However, uncertainties in dust optical properties propagate to its direct effect and the subsequent model response. Inclusion of the indirect aerosol effects improves surface radiation biases at the North Slope of Alaska ARM site due to lower cloud amounts in high-latitude clean-air regions. This leads to improved temperature and height forecasts in this region. Impacts on the global mean model precipitation and large-scale circulation fields were found to be generally small in the short-range forecasts. However, the indirect aerosol effect leads to a strengthening of the low-level monsoon flow over the Arabian Sea and Bay of Bengal and an increase in precipitation over Southeast Asia. Regional impacts on the African Easterly Jet (AEJ) are also presented with the large dust loading in the aerosol climatology enhancing of the heat low over West Africa and weakening the AEJ. This study highlights the importance of including a more realistic treatment of aerosol-cloud interactions in global NWP models and the potential for improved global environmental prediction systems through the incorporation of more complex aerosol schemes.

Mulcahy, J. P.; Walters, D. N.; Bellouin, N.; Milton, S. F.

2014-05-01

78

Proceedings of the First National Workshop on the Global Weather Experiment: Current Achievements and Future Directions, volume 2, part 2  

NASA Technical Reports Server (NTRS)

An assessment of the status of research using Global Weather Experiment (GWE) data and of the progress in meeting the objectives of the GWE, i.e., better knowledge and understanding of the atmosphere in order to provide more useful weather prediction services. Volume Two consists of a compilation of the papers presented during the workshop. These cover studies that addressed GWE research objectives and utilized GWE information. The titles in Part 2 of this volume include General Circulation Planetary Waves, Interhemispheric, Cross-Equatorial Exchange, Global Aspects of Monsoons, Midlatitude-Tropical Interactions During Monsoons, Stratosphere, Southern Hemisphere, Parameterization, Design of Observations, Oceanography, Future Possibilities, Research Gaps, with an Appendix.

1985-01-01

79

Antarctic Weather  

NSDL National Science Digital Library

Visitors to this site can read a discussion about the weather in Anarctica, including why it is so cold, how weather observations are conducted there, and what role the continent plays in the global weather system. Links to related topics, a wind chill calculator, and a Fahrenheit-Celsius-Kelvin temperature converter are also provided.

80

FORMOSAT-7/COSMIC-2 GNSS radio occultation constellation mission for global weather monitoring  

NASA Astrophysics Data System (ADS)

The United States and Taiwan, through an Agreement signed in May 2010, have begun to jointly develop a satellite program to deliver next-generation global navigation satellite system (GNSS) radio occultation (RO) data to users around the world. This Program, known as FORMOSAT-7/COSMIC-2, is the follow-on to the FORMOSAT-3/COSMIC mission, which was a joint US-Taiwan 6-satellite constellation demonstration mission launched in April 2006. The COSMIC mission was the world's first operational GPS radio occultation (GPS-RO) mission for global weather forecast; climate monitoring; atmospheric, ionospheric, and geodetic research. The GPS-RO data from COSMIC has been extremely valuable to the climate, meteorology, and space weather communities, including real-time forecasting users as well as U.S. and international research communities. FORMOSAT-3/COSMIC reached the end of its design life in 2011. The constellation satellites have exhibited some unrecoverable anomalies and consequently the critical real-time satellite observing capability is degrading and may go offline with uncertainty in the coming few years. The National Oceanic and Atmospheric Administration (NOAA) and Taiwan's National Space Organization (NSPO) have recognized the potential GPS-RO data gap due to the degrading COSMIC/FORMOSAT-3 constellation and agreed to implement the follow-on COSMIC-2/FORMOSAT-7 mission in 2010. Both experienced programmatic difficulties in the past two years in the course of implementing the COSMIC-2/FORMOSAT-7 Program; however, significant progress over the past six months has occurred. This paper will provide an overview of the COSMIC2/FORMOSAT-7 Program including the Program goals and objectives. It will also discuss the status of the Program including current satellite and constellation configuration, activities to determine the optimal and minimal ground system architecture to meet data latency requirements, and other discussions on the mission and scientific payload technol- gy that will be used to meet the Program objectives.

Cook, K.; Fong, Chen-Joe; Wenkel, M. J.; Wilczynski, P.; Yen, N.; Chang, G. S.

81

Global Millimeter-Wave Precipitation Retrievals Trained With a Cloud-Resolving Numerical Weather Prediction Model, Part I: Retrieval Design  

Microsoft Academic Search

This paper develops a global precipitation rate retrieval algorithm for the advanced microwave sounding unit (AMSU), which observes 23-191 GHz. The algorithm was trained using a numerical weather prediction (NWP) model (MM5) for 106 globally distributed storms that predicted brightness temperatures consistent with those observed simultaneously by AMSU. Neural networks were trained to retrieve hydrometeor water-paths, peak vertical wind, and

Chinnawat Surussavadee; David H. Staelin

2008-01-01

82

Global magnetosphere-ionosphere-thermosphere simulations - from science to space weather  

NASA Astrophysics Data System (ADS)

Earth's magnetosphere arises from the interaction of the solar wind and interplanetary magnetic field with the internal magnetic field of the Earth. Because the solar wind is highly variable the magnetosphere is very dynamic and host to numerous plasma processes. Since the magnetosphere is fairly accessible for in situ measurements it also serves as a laboratory for the collisionless plasma that makes up most of the cosmos. Attempts to model the global solar wind - magnetosphere interaction go back to the 1980's and are usually based on the MHD equations. Contemporary models are much more complex and are coupled to other sub-models, such as ionosphere-thermosphere and ring current models. Furthermore, ever increasing computer power now allows us to produce many details and processes of the interaction. Space weather forecasting critically depends on global models of the magnetosphere -ionosphere -thermosphere system. However, science-grade models are generally not well suited for operational tasks. In this talk I will address the most important issues that distinguish a science model from an operational model, such as relevance, robustness, efficiency, documentation, and verification. In particular, I will suggest programs that are needed to overcome the "valley of death," i.e., the rocky path from science to forecasting.

Raeder, Joachim

2013-04-01

83

142Nd evidence for early (>4.53 Ga) global differentiation of the silicate Earth.  

PubMed

New high-precision samarium-neodymium isotopic data for chondritic meteorites show that their 142Nd/144Nd ratio is 20 parts per million lower than that of most terrestrial rocks. This difference indicates that most (70 to 95%) of Earth's mantle is compositionally similar to the incompatible element-depleted source of mid-ocean ridge basalts, possibly as a result of a global differentiation 4.53 billion years ago (Ga), within 30 million years of Earth's formation. The complementary enriched reservoir has never been sampled and is probably located at the base of the mantle. These data influence models of Earth's compositional structure and require revision of the timing of global differentiation on Earth's Moon and Mars. PMID:15961629

Boyet, M; Carlson, R W

2005-07-22

84

Mapping global lunar abundance of plagioclase, clinopyroxene and olivine with Interference Imaging Spectrometer hyperspectral data considering space weathering effect  

NASA Astrophysics Data System (ADS)

Mineral mapping of the lunar surface is critical to understanding the Moon's geological diversity and history, yet the global lunar abundance of minerals has not been mapped using hyperspectral data. The Interference Imaging Spectrometer (IIM) of Chang'E-1 mission obtained hyperspectral data of the global lunar surface within the wavelength of 480-960 nm in which major minerals can be discriminated by faint differences in 32 contiguous hyperspectral bands. The effect of space weathering produces multiple endmembers of lunar minerals by obscuring the pure spectra of minerals in different levels. In this study, the distributions of plagioclase, clinopyroxene and olivine on the global lunar surface were mapped with IIM hyperspectral data based on the modified Multiple Endmember Spectral Mixture Analysis (MESMA) method considering the space weathering effect. The distribution of lunar space weathering levels was retrieved as a byproduct of mineral mapping. The mineral mapping results were compared with recent mapping results. Although the wavelength of IIM is limited, it shows that our results are basically consistent with the recent research at both global and local scales. The distribution of space weathering levels is also consistent with the map of optical maturity parameter (OMAT) in most parts of the global lunar surface, especially in the highlands. This study demonstrates that the modified MESMA method is an effective approach to quantitative mapping of the lunar minerals and space weathering levels using hyperspectral data. In the future, more minerals can be mapped with higher accuracy if hyperspectral data with a wider spectral range are used based on the method proposed in this study.

Shuai, Tong; Zhang, Xia; Zhang, Lifu; Wang, Jinnian

2013-01-01

85

Global Silicate Mineralogy of the Moon from the Diviner Lunar Radiometer  

NASA Astrophysics Data System (ADS)

We obtained direct global measurements of the lunar surface using multispectral thermal emission mapping with the Lunar Reconnaissance Orbiter Diviner Lunar Radiometer Experiment. Most lunar terrains have spectral signatures that are consistent with known lunar anorthosite and basalt compositions. However, the data have also revealed the presence of highly evolved, silica-rich lunar soils in kilometer-scale and larger exposures, expanded the compositional range of the anorthosites that dominate the lunar crust, and shown that pristine lunar mantle is not exposed at the lunar surface at the kilometer scale. Together, these observations provide compelling evidence that the Moon is a complex body that has experienced a diverse set of igneous processes.

Greenhagen, Benjamin T.; Lucey, Paul G.; Wyatt, Michael B.; Glotch, Timothy D.; Allen, Carlton C.; Arnold, Jessica A.; Bandfield, Joshua L.; Bowles, Neil E.; Hanna, Kerri L. Donaldson; Hayne, Paul O.; Song, Eugenie; Thomas, Ian R.; Paige, David A.

2010-09-01

86

Global silicate mineralogy of the Moon from the Diviner lunar radiometer.  

PubMed

We obtained direct global measurements of the lunar surface using multispectral thermal emission mapping with the Lunar Reconnaissance Orbiter Diviner Lunar Radiometer Experiment. Most lunar terrains have spectral signatures that are consistent with known lunar anorthosite and basalt compositions. However, the data have also revealed the presence of highly evolved, silica-rich lunar soils in kilometer-scale and larger exposures, expanded the compositional range of the anorthosites that dominate the lunar crust, and shown that pristine lunar mantle is not exposed at the lunar surface at the kilometer scale. Together, these observations provide compelling evidence that the Moon is a complex body that has experienced a diverse set of igneous processes. PMID:20847266

Greenhagen, Benjamin T; Lucey, Paul G; Wyatt, Michael B; Glotch, Timothy D; Allen, Carlton C; Arnold, Jessica A; Bandfield, Joshua L; Bowles, Neil E; Donaldson Hanna, Kerri L; Hayne, Paul O; Song, Eugenie; Thomas, Ian R; Paige, David A

2010-09-17

87

Africa-wide water balance estimation using remote sensing and global weather datasets  

NASA Astrophysics Data System (ADS)

The continent of Africa encompasses diverse ecological systems - from desert to equatorial forest - with major rivers flowing in different directions such as the Congo, Niger, Nile, Senegal and Zambezi. A lack of consistent data or access to important data sets such as rainfall, stream flow and evapotranspiration has been a barrier to developing Africa-wide water atlas in the past. We used globally available and consistent weather and remotely sensed datasets to estimate annual average (2001-2009) actual evapotranspiration (ET) at 1 km scale for the entire continent from the 8-day ET estimates using the Simplified Surface Energy Balance (SSEB) model. Thermal and optical remotely sensed data from the MODIS (Moderate Resolution Imaging Spectroradiometer) sensor were used. Annual rainfall was generated from the widely used climatological monthly rainfall summaries developed by FAO (1961-1990) at 10 km resolution. Spatially explicit annual water balance was calculated as the difference between annual rainfall and actual ET at 1 km resolution. The result was summarized by major river basins to estimate the relative contribution of the riparian countries in the basin. From this study, we estimated the total annual runoff depth for Africa to be a depth of 142.5 mm or 4,483 km3 (using a continental area of 30.65 km2). This figure compares within 4 percent of an average runoff estimate reported in the literature.

Senay, G. B.; Pengra, B.; Bohms, S.; Singh, A.; Verdin, J. P.

2010-12-01

88

Carbon dioxide efficiency of terrestrial enhanced weathering.  

PubMed

Terrestrial enhanced weathering, the spreading of ultramafic silicate rock flour to enhance natural weathering rates, has been suggested as part of a strategy to reduce global atmospheric CO2 levels. We budget potential CO2 sequestration against associated CO2 emissions to assess the net CO2 removal of terrestrial enhanced weathering. We combine global spatial data sets of potential source rocks, transport networks, and application areas with associated CO2 emissions in optimistic and pessimistic scenarios. The results show that the choice of source rocks and material comminution technique dominate the CO2 efficiency of enhanced weathering. CO2 emissions from transport amount to on average 0.5-3% of potentially sequestered CO2. The emissions of material mining and application are negligible. After accounting for all emissions, 0.5-1.0 t CO2 can be sequestered on average per tonne of rock, translating into a unit cost from 1.6 to 9.9 GJ per tonne CO2 sequestered by enhanced weathering. However, to control or reduce atmospheric CO2 concentrations substantially with enhanced weathering would require very large amounts of rock. Before enhanced weathering could be applied on large scales, more research is needed to assess weathering rates, potential side effects, social acceptability, and mechanisms of governance. PMID:24597739

Moosdorf, Nils; Renforth, Phil; Hartmann, Jens

2014-05-01

89

Weather Avoidance Guidelines for NASA Global Hawk High-Altitude UAS  

NASA Technical Reports Server (NTRS)

NASA operates two Global Hawk unmanned aircraft systems for Earth Science research projects. In particular, they are used in the Hurricane and Severe Storm Sentinel (HS3) project during 2012, 2013, and 2014 to take measurements from the environment around tropical cyclones, and from directly above tropical cyclones. There is concern that strict adherence to the weather avoidance rules used in 2012 may sacrifice the ability to observe important science targets. We have proposed modifications to these weather avoidance rules that we believe will improve the ability to observe science targets without compromising aircraft safety. The previous guidelines, used in 2012, specified: Do not approach thunderstorms within 25 nm during flight at FL500 or below. When flying above FL500: Do not approach reported lightning within 25NM in areas where cloud tops are reported at FL500 or higher. Aircraft should maintain at least 10000 ft vertical separation from reported lightning if cloud tops are below FL500. No over-flight of cumulus tops higher than FL500. No flight into forecast or reported icing conditions. No flight into forecast or reported moderate or severe turbulence Based on past experience with high-altitude flights over tropical cyclones, we have recommended changing this guidance to: Do not approach thunderstorms within 25 nm during flight at FL500 or below. Aircraft should maintain at least 5000 ft vertical separation from significant convective cloud tops except: a) When cloud tops above FL500: In the event of reported significant lightning activity or indicators of significant overshooting tops, do not approach within 10-25 nm, depending on pilot discretion and advice from Mission Scientist. b) When cloud tops are below FL500, maintain 10000 ft separation from reported significant lightning or indicators of significant overshooting tops. No flight into forecasted or reported icing conditions. No flight into forecasted or reported moderate or severe turbulence The key changes have to do with overflight of high convective cloud tops and those producing lightning. Experience shows that most tropical oceanic convection (including that in tropical cyclones) is relatively gentle even if the cloud tops are quite high, and can be safely overflown. Exceptions are convective elements producing elevated lightning flash rates (more than just the occasional flash, which would trigger avoidance under the previous rules) and significant overshooting cloud tops.

Cecil, Daniel J.; Zipser, Edward J.; Velden, Chris; Monette, Sarah; Heymsfield, Gerry; Braun, Scott; Newman, Paul; Black, Pete; Black, Michael; Dunion, Jason

2014-01-01

90

Application of dynamical systems theory to global weather phenomena revealed by satellite imagery  

NASA Technical Reports Server (NTRS)

Theoretical studies of low frequency and seasonal weather variability; dynamical properties of observational and general circulation model (GCM)-generated records; effects of the hydrologic cycle and latent heat release on extratropical weather; and Earth-system science studies are summarized.

Saltzman, Barry; Ebisuzaki, Wesley; Maasch, Kirk A.; Oglesby, Robert; Pandolfo, Lionel; Tang, Chung-Muh

1989-01-01

91

Global near-realtime monitoring of Tropical Cyclones Using Weather Satellites  

NASA Astrophysics Data System (ADS)

The Naval Research Laboratory maintains a satellite web portal that monitors global tropical cyclones in every basin on a continuing basis. The portal is used routinely by agencies around the world in forecasting operations and the issuance of warnings. Products from this site are widely redistributed and published frequently in journal articles, seasonal storm summaries, and ongoing World Wide Web discussions. Traditionally, weather satellite reconnaissance of tropical cyclones has depended on the interpretation of visible and infrared imagery. But such methods have limitations. Visible images are not available during the nighttime, and both kinds of imagery often fail to detect important structure, including storm eyes, which are vital for determining the strength and location of tropical systems. Thus, the portal supplements visible and infrared coverage with products from satellite microwave sensors. These sensors penetrate higher clouds to reveal important detail about low-level cloud and precipitation features. The first part of the talk will discuss how these various products can be used together for improved analysis. The second part of talk will present information about tropical cyclone structure. Surface winds from aircraft will be compared to features seen in passive microwave images. We see that low brightness temperature features on 85 GHz images often corresponding to wind maxima near the sea surface. We shall make some inferences about how the observation of specific structures in satellite images can help characterize the wind field when no aircraft data are available. Special attention will be paid to multiple eye walls apparent on satellite images. These are associated with very intense storms which undergo an evolutionary process not observed in weaker systems.

Lee, T.; Hawkins, J.; Turk, F.; Miller, S.; Sampson, C.; Kuciauskas, A.; Richardson, K.; Kent, J.

2006-12-01

92

Modeling the weather impact on aviation in a global air traffic model  

NASA Astrophysics Data System (ADS)

Weather has a strong impact on aviation safety and efficiency. For a better understanding of that impact, especially of thunderstorms and similar other severe hazards, we pursued a modeling approach. We used the detailed simulation software (NAVSIM) of worldwide air traffic, developed by Rokitansky [Eurocontrol, 2005] and implemented a specific weather module. NAVSIM models each aircraft with its specific performance characteristics separately along preplanned and prescribed routes. The specific weather module in its current version simulates a thunderstorm as an impenetrable 3D object, which forces an aircraft to circumvent the latter. We refer to that object in general terms as a weather object. The Cb-weather object, as a specific weather object, is a heuristic model of a real thunderstorm, with its characteristics based on actually observed satellite and precipitation radar data. It is comprised of an upper volume, mostly the anvil, and a bottom volume, the up- and downdrafts and the lower outflow area [Tafferner and Forster, 2009; Kober and Tafferner 2009; Zinner et al, 2008]. The Cb-weather object is already implemented in NAVSIM, other weather objects like icing and turbulence will follow. This combination of NAVSIM with a weather object allows a detailed investigation of situations where conflicts exist between planned flight routes and adverse weather. The first objective is to simulate the observed circum-navigation in NAVSIM. Real occurring routes will be compared with simulated ones. Once this has successfully completed, NAVSIM offers a platform to assess existing rules and develop more efficient strategies to cope with adverse weather. An overview will be given over the implementation status of weather objects within NAVSIM and first results will be presented. Cb-object data provision by A. Tafferner, C. Forster, T. Zinner, K. Kober, M. Hagen (DLR Oberpfaffenhofen) is greatly acknowledged. References: Eurocontrol, VDL Mode 2 Capacity Analysis through Simulations: WP3.B - NAVSIM Overview and Validation Results, Edition 1.2, 2005 Kober K. and A. Tafferner. Tracking and nowcasting of convective cells using remote sensing data from radar and satellite, Meteorologische Zeitschrift, 1 (No. 18), 75-84, 2009 Tafferner A. and C. Forster, Improvement of thunderstorm hazard information for pilots through a ground based weather information and management system, Eighth USA/Europe Air Traffic Management Research and Development Seminar (submitted), 2009 Zinner, T., H. Mannstein, A. Tafferner. Cb-TRAM: Tracking and monitoring severe convection from onset over rapid development to mature phase using multi-channel Meteosat-8 SEVIRI data, Meteorol. Atmos. Phys., 101, 191-210, 2008

Himmelsbach, S.; Hauf, T.; Rokitansky, C. H.

2009-09-01

93

Weather One  

NSDL National Science Digital Library

This website contains summaries and lessons about various aspects of weather. This includes the seasons, types of clouds, air, winds, global warming, hurricanes, tornadoes and lightning. Worksheets are provided to accompany the lesson themes.

Friend, Duane

94

World Weather Watch: Global Observing System - Satellite sub-System. Information on the Application of Meteorological Satellite Data in Routine Operations and Research: Abstracts, Annual Summaries and Bibliographies.  

National Technical Information Service (NTIS)

Contributions from countries participating in the World Weather Watch program are listed. Emphasis is on the Global Observing System: Satellite sub-system. Bibliographic information and an abstract of each contribution are provided.

1978-01-01

95

Four-dimensional ensemble-variational data assimilation for global deterministic weather prediction  

NASA Astrophysics Data System (ADS)

The goal of this study is to evaluate a version of the ensemble-variational data assimilation approach (EnVar) for possible replacement of 4D-Var at Environment Canada for global deterministic weather prediction. This implementation of EnVar relies on 4-D ensemble covariances, obtained from an ensemble Kalman filter, that are combined in a vertically dependent weighted average with simple static covariances. Verification results are presented from a set of data assimilation experiments over two separate 6-week periods that used assimilated observations and model configuration very similar to the currently operational system. To help interpret the comparison of EnVar versus 4D-Var, additional experiments using 3D-Var and a version of EnVar with only 3-D ensemble covariances are also evaluated. To improve the rate of convergence for all approaches evaluated (including EnVar), an estimate of the cost function Hessian generated by the quasi-Newton minimization algorithm is cycled from one analysis to the next. Analyses from EnVar (with 4-D ensemble covariances) nearly always produce improved, and never degraded, forecasts when compared with 3D-Var. Comparisons with 4D-Var show that forecasts from EnVar analyses have either similar or better scores in the troposphere of the tropics and the winter extra-tropical region. However, in the summer extra-tropical region the medium-range forecasts from EnVar have either similar or worse scores than 4D-Var in the troposphere. In contrast, the 6 h forecasts from EnVar are significantly better than 4D-Var relative to radiosonde observations for both periods and in all regions. The use of 4-D versus 3-D ensemble covariances only results in small improvements in forecast quality. By contrast, the improvements from using 4D-Var versus 3D-Var are much larger. Measurement of the fit of the background and analyzed states to the observations suggests that EnVar and 4D-Var can both make better use of observations distributed over time than 3D-Var. In summary, the results from this study suggest that the EnVar approach is a viable alternative to 4D-Var, especially when the simplicity and computational efficiency of EnVar are considered. Additional research is required to understand the seasonal dependence of the difference in forecast quality between EnVar and 4D-Var in the extra-tropics.

Buehner, M.; Morneau, J.; Charette, C.

2013-09-01

96

Estimation of confidence intervals of global horizontal irradiance obtained from a weather prediction model  

NASA Astrophysics Data System (ADS)

Many photovoltaic (PV) systems have been installed in Japan after the introduction of the Feed-in-Tariff. For an energy management of electric power systems included many PV systems, the forecast of the PV power production are useful technology. Recently numerical weather predictions have been applied to forecast the PV power production while the forecasted values invariably have forecast errors for each modeling system. So, we must use the forecast data considering its error. In this study, we attempted to estimate confidence intervals for hourly forecasts of global horizontal irradiance (GHI) values obtained from a mesoscale model (MSM) de-veloped by the Japan Meteorological Agency. In the recent study, we found that the forecasted values of the GHI of the MSM have two systematical forecast errors; the first is that forecast values of the GHI are depended on the clearness indices, which are defined as the GHI values divided by the extraterrestrial solar irradiance. The second is that forecast errors have the seasonal variations; the overestimation of the GHI forecasts is found in winter while the underestimation of those is found in summer. The information of the errors of the hourly GHI forecasts, that is, confidence intervals of the forecasts, is of great significance for planning the energy management included a lot of PV systems by an electric company. On the PV systems, confidence intervals of the GHI forecasts are required for a pinpoint area or for a relatively large area control-ling the power system. For the relatively large area, a spatial-smoothing method of the GHI values is performed for both the observations and forecasts. The spatial-smoothing method caused the decline of confidence intervals of the hourly GHI forecasts on an extreme event of the GHI forecast (a case of large forecast error) over the relatively large area of the Tokyo electric company (approximately 68 % than for a pinpoint forecast). For more credible estimation of the confidence intervals, it is required to consider the location of the installed PV systems or its capacity over the region.

Ohtake, Hideaki; Gari da Silva Fonseca, Joao, Jr.; Takashima, Takumi; Oozeki, Takashi; Yamada, Yoshinori

2014-05-01

97

Thermal Expansion Calculation of Silicate Glasses at 210°C, Based on the Systematic Analysis of Global Databases  

Microsoft Academic Search

Thermal expansion data for more than 5500 compositions of silicate glasses were analyzed statistically. These data were gathered from the scientific literature, summarized in SciGlass© 6.5, a new version of the well known glass property database and information system. The analysis resulted in a data reduction from 5500 glasses to a core of 900, where the majority of the published

Fluegel

2010-01-01

98

Vertical structure of the wind field during the Special Observing Period I of the Global Weather Experiment  

NASA Technical Reports Server (NTRS)

The vertical structure of the global atmosphere is analyzed for selected periods of the Special Observing Period I (SOP-I) for the Global Weather Experiment (GWE). The analysis consists of projection of the stream-function and velocity potential at 200 and 850 mb on spherical harmonics and of the wind and height fields on the normal modes of a linearized form of the primitive equations for a basic state at rest. The kinematic vertical structure is discussed in terms of correlation coefficients of the 200 mb and 850 mb winds and analysis of the internal and external normal modes of the primitive equations. The reliability of the results is checked by applying the same analysis methods to data sets obtained from three different institutions: Geophysical Fluid Dynamics Laboratory (GFDL), European Center for Medium Range Weather Forecasting (ECMWF), and Goddard Laboratory for the Atmospheres (GLA). It is found that, on a global basis, vertically reversing circulations are as important as the equivalent barotropic structures. For the verticaly reversing components, the gravity and mixed Rossby-gravity modes have contributions of the same order of magnitude as those of the Rossby modes in tropical latitudes.

Paegle, J. N.; Paegle, J.; Zhen, Z.; Sampson, G.

1986-01-01

99

Research Review: Walter Orr Roberts on the Atmosphere, Global Pollution and Weather Modification  

ERIC Educational Resources Information Center

Global Atmospheric Research Program is envisaged to study various aspects of the environment for the whole globe. Describes programs undertaken and the international problems involved in implementing results of such research on a global level. (PS)

Jacobsen, Sally

1973-01-01

100

Comparison of Large-scale Cloud Schemes in Single-column and Global Versions of a Numerical Weather Prediction Model  

NASA Astrophysics Data System (ADS)

Large-scale cloud parameterization has been used in the numerical models for weather forecasting and climate prediction in order to represent cloud generated from non-convective sources that partially occupies a grid box. We have developed the cloud parameterization for Korea's own global numerical weather prediction (NWP) model since 2012, and as the first step for the development, the performances of existing cloud schemes are compared in single-column and global versions of a NWP model. The Met Office Unified Model is used as the testbed model, and three cloud schemes are considered in the model separately. One is the diagnostic cloud fraction and diagnostic condensate scheme (DIAG scheme), another is the diagnostic cloud fraction and prognostic condensate scheme (DCPC scheme), and the other is the prognostic cloud fraction and prognostic condensate scheme (PC2 scheme). The single-column simulation with each cloud scheme is performed during the Tropical Warm Pool-International Cloud Experiment (TWP-ICE) period (18 January-13 February 2006), and the global simulation is performed during April 2012. The simulation results are also compared with the observation and reanalysis data. In both single-column and global simulations, the DIAG scheme underestimates low and medium clouds compared with the observations, which is mostly due to the underestimated humidity in the low-to-mid troposphere. The biases are aggravated in both single-column and global simulations with the DCPC scheme. The PC2 scheme produces larger cloud fraction compared with the DIAG scheme, which is mainly contributed by the detrainment from convection. The cloud fraction from the PC2 scheme is also larger compared with the observations. The difference in the cloud representation among the cloud schemes results in the difference in the radiation budget, which in turn affects the temperature. Besides, relative humidity and precipitation are changed through the interactions among other physical processes such as microphysics. More detailed results will be shown in the meeting.

Choi, Hyun-Joo; Kim, So-Young; Jin, Emilia Kyung

2013-04-01

101

Assessment of the Aviation Weather Center Global Forecasts of Mesoscale Convective Systems  

Microsoft Academic Search

This paper examines the precision of location and top height of mesoscale convective systems, as forecast by the Aviation Weather Center (AWC). The examination was motivated by the Mediterranean Israeli Dust Experiment (MEIDEX) on the space shuttle Columbia, aimed to image transient luminous events (TLEs), such as sprites, jets, and elves, from orbit. Mesoscale convective systems offer a high probability

Baruch Ziv; Yoav Yair; Karin Presman; Martin Füllekrug

2004-01-01

102

Assimilation of global ASCAT soil moisture observations in the ECMWF Numerical Weather Prediction Model  

Microsoft Academic Search

The European Centre for Medium-Range Weather Forecasts (ECMWF) currently prepares for the assimilation of soil moisture data derived from advanced scatterometer (ASCAT) measurements and from the Soil Moisture and Ocean Salinity Mission (SMOS). Here we will report on first results from the assimilation of ASCAT data into the Integrated Forecasting System of the ECMWF. ASCAT is part of the MetOp

K. Scipal; M. Drusch; G. Balsamo; P. de Rosnay

2009-01-01

103

Long Range Weather Prediction III: Miniaturized Distributed Sensors for Global Atmospheric Measurements.  

National Technical Information Service (NTIS)

We continue consideration of ways-and-means for creating, in an evolutionary, ever-more-powerful manner, a continually-updated data-base of salient atmospheric properties sufficient for finite differenced integration-based, high-fidelity weather predictio...

E. Teller C. Leith G. Canavan L. Wood

2001-01-01

104

Developing a Global, Short-Term Fire Weather Forecasting Tool Using NWP Input Meteorology and Satellite Fire Data  

NASA Astrophysics Data System (ADS)

In order to meet the emerging need for better estimates of biomass burning emissions in air quality and climate models, a statistical model is developed to characterize the effect of a given set of meteorological conditions on the following day's fire activity, including ignition and spread potential. Preliminary tests are conducted within several spatial domains of the North American boreal forest by investigating a wide range of meteorological information, including operational fire weather forecasting indices, such as the Canadian Forest Fire Danger Rating System (CFFDRS). However, rather than using local noon surface station data, the six components of the CFFDRS are modified to use inputs from the North America Regional Reanalysis (NARR) and the Navy's Operational Global Atmospheric Prediction System Model (NOGAPS). The Initial Spread Index (ISI) and the Fire Weather Index (FWI) are shown to be the most relevant components of the CFFDRS for short-term changes in fire activity. However, both components are found to be highly sensitive to variations in relative humidity and wind speed input data. Several variables related to fire ignition from dry lighting, such as instability and the synoptic pattern, are also incorporated. Cases of fire ignition, growth, decay, and extinction are stratified using satellite fire observations from the Geostationary Operational Environmental Satellites (GOES) and the MODerate Resolution Imaging Spectroradiometer (MODIS) and compared to the available suite of meteorological information. These comparisons reveal that combinations of meteorological variables, such as the FWI, ISI, and additional indices developed for this study, produce the greatest separability between major fire growth and decay cases, which are defined by the observed change in fire counts and fire radiative power. This information is used to derive statistical relationships affecting the short-term changes in fire activity and subsequently applied to other spatial domains across North America, with the ultimate goal of producing a global, short-term fire weather forecasting tool.

Peterson, D. A.; Hyer, E. J.; Wang, J.

2011-12-01

105

Significant increases in global weathering during Oceanic Anoxic Events 1a and 2 indicated by calcium isotopes  

NASA Astrophysics Data System (ADS)

Calcium-isotope ratios (? 44/42Ca) were measured in carbonate-rich sedimentary sections deposited during Oceanic Anoxic Events 1a (Early Aptian) and 2 (Cenomanian-Turonian). In sections from Resolution Guyot, Mid-Pacific Mountains; Coppitella, Italy; and the English Chalk at Eastbourne and South Ferriby, UK, a negative excursion in ? 44/42Ca of ~ 0.20‰ and ~ 0.10‰ is observed for the two events. These ? 44/42Ca excursions occur at the same stratigraphic level as the carbon-isotope excursions that define the events, but do not correlate with evidence for carbonate dissolution or lithological changes. Diagenetic and temperature effects on the calcium-isotope ratios can be discounted, leaving changes in global seawater composition as the most probable explanation for ? 44/42Ca changes in four different carbonate sections. An oceanic box model with coupled strontium- and calcium-isotope systems indicates that a global weathering increase is likely to be the dominant driver of transient excursions in calcium-isotope ratios. The model suggests that contributions from hydrothermal activity and carbonate dissolution are too small and short-lived to affect the oceanic calcium reservoir measurably. A modelled increase in weathering flux, on the order of three times the modern flux, combined with increased hydrothermal activity due to formation of the Ontong-Java Plateau (OAE1a) and Caribbean Plateau (OAE2), can produce trends in both calcium and strontium isotopes that match the signals recorded in the carbonate sections. This study presents the first major-element record of a weathering response to Oceanic Anoxic Events.

Blättler, Clara L.; Jenkyns, Hugh C.; Reynard, Linda M.; Henderson, Gideon M.

2011-09-01

106

Chemical weathering rates of a soil chronosequence on granitic alluvium: I. Quantification of mineralogical and surface area changes and calculation of primary silicate reaction rates  

Microsoft Academic Search

Mineral weathering rates are determined for a series of soils ranging in age from 0.2–3000 Ky developed on alluvial terraces near Merced in the Central Valley of California. Mineralogical and elemental abundances exhibit time-dependent trends documenting the chemical evolution of granitic sand to residual kaolinite and quartz. Mineral losses with time occur in the order: hornblende > plagioclase > K-feldspar.

Art F. White; Alex E. Blum; Marjorie S. Schulz; Tom D. Bullen; Jennifer W. Harden; Maria L. Peterson

1996-01-01

107

Investigating the Climate System: WEATHER. Global Awareness Tour. Problem-Based Classroom Modules  

ERIC Educational Resources Information Center

With support from National Aeronautics and Space Administration's (NASA's) Goddard Space Flight Center, Institute for Global Environmental Strategies (IGES) has developed educational materials that incorporate information and data from the Tropical Rainfall Measuring Mission (TRMM), a joint satellite mission between the United States and Japan.…

Passow, Michael J.

2003-01-01

108

Severe convective weather in the context of a nighttime global warming  

Microsoft Academic Search

The recent finding that most of the global warming observed these past decades is due to an increase of the nighttime temperature may have important implications on severe storms occurrence. Indeed, the daily minimum temperature which is generally recorded in the early morning is an approximation of the wet bulb potential temperature observed during the following afternoon, which is a

Jean Dessens

1995-01-01

109

Index of Air Weather Service Technical Publications.  

National Technical Information Service (NTIS)

This index lists technical publications of the US Air Force Weather Service including its subordinate units. These units include the Air Force Global Weather Central, US Air Force Environmental Technical Applications Center, 1st Weather Wing, 2nd Weather ...

1981-01-01

110

Enhanced Cenozoic chemical weathering and the subduction of pelagic carbonate  

Microsoft Academic Search

THE observed trend of increasing oceanic 87Sr\\/86Sr ratios during the late Cenozoic led Raymo et al.1 to propose that chemical weathering rates increased at this time as a result of enhanced weatherability of silicate rocks. They suggested that this was due in turn to continential uplift, primarily in the Himalayas and the Andes. Because weathering involves the reaction of silicates

Ken Caldeira

1992-01-01

111

Global chemical weather forecasts for field campaign planning: predictions and observations of large-scale features during MINOS, CONTRACE, and INDOEX  

Microsoft Academic Search

The first global tropospheric forecasts of O3 and its precursors have been used in the daily flight planning of field measurement campaigns. The 3-D chemistry-transport model MATCH-MPIC is driven by meteorological data from a weather center (NCEP) to produce daily 3-day forecasts of the global distributions of O3 and related gases, as well as regional CO tracers. This paper describes

M. G. Lawrence; P. J. Rasch; R. von Kuhlmann; J. Williams; H. Fischer; M. de Reus; J. Lelieveld; P. J. Crutzen; M. Schultz; P. Stier; H. Huntrieser; J. Heland; A. Stohl; C. Forster; H. Elbern; H. Jakobs; R. R. Dickerson

2003-01-01

112

Effects of climate on chemical weathering in watersheds  

USGS Publications Warehouse

Climatic effects on chemical weathering are evaluated by correlating variations in solute concentrations and fluxes with temperature, precipitation, runoff, and evapotranspiration (ET) for a worldwide distribution of sixty-eight watersheds underlain by granitoid rock types. Stream solute concentrations are strongly correlated with proportional ET loss, and evaporative concentration makes stream solute concentrations an inapprorpiate surrogate for chemical weathering. Chemical fluxes are unaffected by ET, and SiO2 and Na weathering fluxes exhibit systematic increases with precipitation, runoff, and temperature. However, warm and wet watersheds produce anomalously rapid weathering rates. A proposed model that provides an improved prediction of weathering rates over climatic extremes is the product of linear precipitation and Arrhenius temperature functions. The resulting apparent activation energies based on SiO2 and Na fluxes are 59.4 and 62.5 kJ.mol-1, respectively. The coupling between temperature and precipitation emphasizes the importance of tropical regions in global silicate weathering fluxes, and suggests it is not representative to use continental averages for temperature and precipitation in the weathering rate functions of global carbon cycling and climatic change models. Fluxes of K, Ca, and Mg exhibit no climatic correlation, implying that other processes, such as ion exchange, nutrient cycling, and variations in lithology, obscure any climatic signal. -from Authors

White, A. F.; Blum, A. E.

1995-01-01

113

A comparison of Global Positioning System retrieved precipitable water vapor with the numerical weather prediction analysis data over the Japanese Islands  

Microsoft Academic Search

Behavior of precipitable water vapor (PWV) routinely retrieved from the nationwide array of the Global Positioning System (GPS) established by Geographical Survey Institute (GSI) of Japan are compared with the Japan area objective analysis data for numerical weather prediction (NWP) of the Japan Meteorological Agency (JMA). The array used here has a spatial resolution of about 50 km for monitoring

Tetsuya Iwabuchi; Isao Naito; Nobutaka Mannoji

2000-01-01

114

Frequencies and Characteristics of Global Oceanic Precipitation from Shipboard Present-Weather Reports  

NASA Technical Reports Server (NTRS)

Ship reports of present weather obtained from the Comprehensive Ocean-Atmosphere Data Set are analyzed for the period 1958-91 in order to elucidate regional and seasonal variations in the climatological frequency, phase, intensity, and character of oceanic precipitation. Specific findings of note include the following: 1) The frequency of thunderstorm reports, relative to all precipitation reports, is a strong function of location, with thunderstorm activity being favored within 1000-3000 km of major tropical and subtropical land masses, while being quite rare at other locations, even within the intertropical convergence zone. 2) The latitudinal frequency of precipitation over the southern oceans increases steadily toward the Antarctic continent and shows relatively little seasonal variation. The frequency of convective activity, however, shows considerable seasonal variability, with sharp winter maxima occurring near 38 deg. latitude in both hemispheres. 3) Drizzle is the preferred form of precipitation in a number of regions, most of which coincide with known regions of persistent marine stratus and stratocumulus in the subtropical highs. Less well documented is the high relative frequency of drizzle in the vicinity of the equatorial sea surface temperature front in the eastern Pacific. 4) Regional differences in the temporal scale of precipitation events (e.g., transient showers versus steady precipitation) are clearly depicted by way of the ratio of the frequency of precipitation at the observation time to the frequency of all precipitation reports, including precipitation during the previous hour. The results of this study suggest that many current satellite rainfall estimation techniques may substantially underestimate the fractional coverage or frequency of precipitation poleward of 50 deg. latitude and in the subtropical dry zones. They also draw attention to the need to carefully account for regional differences in the physical and spatial properties of rainfall when developing calibration relationships for satellite algorithms.

Petty, Grant W.

1995-01-01

115

Rocks, Weathering, and Erosional Landscapes  

NSDL National Science Digital Library

Students will identify principal rock forming silicate minerals and distinguish their relative stability when exposed to weathering; identify sedimentary, igneous and metamorphic rocks and deduce the relative resistance based on mineral composition and texture;and finally relate erosional landscapes to the differential weathering and erosion of rocks of varying strengths. Designed for a geomorphology course

Hanson, Lindley

116

The Mid-Cretaceous Super Plume, carbon dioxide, and global warming  

Microsoft Academic Search

Carbon-dioxide releases associated with a mid-Cretaceous super plume and the emplacement of the Ontong-Java Plateau have been suggested as a principal cause of the mid-Cretaceous global warming. We developed a carbonate-silicate cycle model to quantify the possible climatic effects of these CO2 releases, utilizing four different formulations for the rate of silicate-rock weathering as a function of atmospheric CO2. We

Ken Caldeira; Michael R. Rampino

1991-01-01

117

Weather Avoidance Guidelines for NASA Global Hawk High-Altitude Unmanned Aircraft Systems (UAS)  

NASA Technical Reports Server (NTRS)

The current Global Hawk flight rules would probably not have been effective in the single event of greatest concern (the Emily encounter). The cloud top had not reached 50,000 ft until minutes before the encounter. The TOT and lightning data would not have been available until near the overflight time since this was a rapidly growing cell. This case would have required a last-minute diversion when lightning became frequent. Avoiding such a cell probably requires continual monitoring of the forward camera and storm scope, whether or not cloud tops have been exceeding specific limits. However, the current overflight rules as strictly interpreted would have prohibited significant fractions of the successful Global Hawk overpasses of Karl and Matthew that proved not to be hazardous. Many other high altitude aircraft (ER-2 and Global Hawk) flights in NASA tropical cyclone field programs have successfully overflown deep convective clouds without incident.The convective cell that caused serious concern about the safety of the ER-2 in Emily was especially strong for a tropical cyclone environment, probably as strong or stronger than any that was overflown by the ER-2 in 20 previous flights over tropical cyclones. Specifically, what made that cell a safety concern was the magnitude of the vertical velocity of the updraft, at least 20 m/s (4000 ft/minute) at the time the ER-2 overflew it. Such a strong updraft can generate strong gravity waves at and above the tropopause, posing a potential danger to aircraft far above the maximum altitude of the updraft itself or its associated cloud top. Indeed, the ER-2 was probably at least 9000 ft above that cloud top. Cloud-top height, by itself, is not an especially good indicator of the intensity of convection and the likelihood of turbulence. Nor is overflying high cloud tops (i.e. > 50,000 ft) of particular concern unless there is other evidence of very strong convective updrafts beneath those tops in the path of the aircraft. center dot Lightning, especially lightning with a high flash rate, is well correlated with convective intensity. Lightning with a minimal flash rate (say 1-3 flashes per minute) is indicative of updraft speeds of about 10 m/s in the mixed phase region where charge is being separated, generally at altitudes about 20-25 kft in a hurricane. That is still stronger than typical updrafts (more like 5 m/s). An unresolved issue is whether there is a high and instantaneous correlation between vertical velocity in the middle troposphere (necessary for lightning generation) and near cloud top (more direct concern for overflights).

Cecil, Daniel J.; Zipser, Edward J.; Velden, Chris S.; Monette, Sarah A.; Heymsfield, Gerald M.; Braun, Scott A.; Newman, Paul A.; Black, Peter G.; Black, Michael L.; Dunion, Jason P.

2014-01-01

118

Proterozoic oxygen rise linked to shifting balance between seafloor and terrestrial weathering.  

PubMed

A shift toward higher atmospheric oxygen concentration during the late Proterozoic has been inferred from multiple indirect proxies and is seen by many as a prerequisite for the emergence of complex animal life. However, the mechanisms controlling the level of oxygen throughout the Proterozoic and its eventual rise remain uncertain. Here we use a simple biogeochemical model to show that the balance between long-term carbon removal fluxes via terrestrial silicate weathering and ocean crust alteration plays a key role in determining atmospheric oxygen concentration. This balance may be shifted by changes in terrestrial weatherability or in the generation rate of oceanic crust. As a result, the terrestrial chemical weathering flux may be permanently altered-contrasting with the conventional view that the global silicate weathering flux must adjust to equal the volcanic CO2 degassing flux. Changes in chemical weathering flux in turn alter the long-term supply of phosphorus to the ocean, and therefore the flux of organic carbon burial, which is the long-term source of atmospheric oxygen. Hence we propose that increasing solar luminosity and a decrease in seafloor spreading rate over 1,500-500 Ma drove a gradual shift from seafloor weathering to terrestrial weathering, and a corresponding steady rise in atmospheric oxygen. Furthermore, increased terrestrial weatherability during the late Neoproterozoic may explain low temperature, increases in ocean phosphate, ocean sulfate, and atmospheric oxygen concentration at this time. PMID:24927553

Mills, Benjamin; Lenton, Timothy M; Watson, Andrew J

2014-06-24

119

Proterozoic oxygen rise linked to shifting balance between seafloor and terrestrial weathering  

PubMed Central

A shift toward higher atmospheric oxygen concentration during the late Proterozoic has been inferred from multiple indirect proxies and is seen by many as a prerequisite for the emergence of complex animal life. However, the mechanisms controlling the level of oxygen throughout the Proterozoic and its eventual rise remain uncertain. Here we use a simple biogeochemical model to show that the balance between long-term carbon removal fluxes via terrestrial silicate weathering and ocean crust alteration plays a key role in determining atmospheric oxygen concentration. This balance may be shifted by changes in terrestrial weatherability or in the generation rate of oceanic crust. As a result, the terrestrial chemical weathering flux may be permanently altered—contrasting with the conventional view that the global silicate weathering flux must adjust to equal the volcanic CO2 degassing flux. Changes in chemical weathering flux in turn alter the long-term supply of phosphorus to the ocean, and therefore the flux of organic carbon burial, which is the long-term source of atmospheric oxygen. Hence we propose that increasing solar luminosity and a decrease in seafloor spreading rate over 1,500–500 Ma drove a gradual shift from seafloor weathering to terrestrial weathering, and a corresponding steady rise in atmospheric oxygen. Furthermore, increased terrestrial weatherability during the late Neoproterozoic may explain low temperature, increases in ocean phosphate, ocean sulfate, and atmospheric oxygen concentration at this time.

Mills, Benjamin; Lenton, Timothy M.; Watson, Andrew J.

2014-01-01

120

Weather One  

NSDL National Science Digital Library

From the University of Illinois Extension comes the Weather One instructional Web site for kids. The lesson consists of six pages that cover various weather related topics including seasons, clouds, the atmosphere, wind, global warming, and storms. Each page describes the particular subject, provides related photographs, and contains several activities that reinforce the learning. For example, the clouds page shows how kids can make a cloud and create a collage out of simple material found around the house. The effective organization and clean look of the site will surely make it easy for students to follow and enjoy.

1969-12-31

121

Predicting Seasonal Weather  

NSDL National Science Digital Library

This module is about a new method of predicting seasonal weather. The site describes the effects of El Nino on global weather and the accuracy of the new model. It includes links to classroom resources for a variety of weather-based units.

Dybas, Cheryl

2008-12-07

122

Direct measurement of the combined effects of lichen, rainfall, and temperature onsilicate weathering  

USGS Publications Warehouse

A key uncertainty in models of the global carbonate-silicate cycle and long-term climate is the way that silicates weather under different climatologic conditions, and in the presence or absence of organic activity. Digital imaging of basalts in Hawaii resolves the coupling between temperature, rainfall, and weathering in the presence and absence of lichens. Activation energies for abiotic dissolution of plagioclase (23.1 ?? 2.5 kcal/mol) and olivine (21.3 ?? 2.7 kcal/mol) are similar to those measured in the laboratory, and are roughly double those measured from samples taken underneath lichen. Abiotic weathering rates appear to be proportional to rainfall. Dissolution of plagioclase and olivine underneath lichen is far more sensitive to rainfall.

Brady, P. V.; Dorn, R. I.; Brazel, A. J.; Clark, J.; Moore, R. B.; Glidewell, T.

1999-01-01

123

Direct measurement of the combined effects of lichen, rainfall, and temperature onsilicate weathering  

NASA Astrophysics Data System (ADS)

A key uncertainty in models of the global carbonate-silicate cycle and long-term climate is the way that silicates weather under different climatologic conditions, and in the presence or absence of organic activity. Digital imaging of basalts in Hawaii resolves the coupling between temperature, rainfall, and weathering in the presence and absence of lichens. Activation energies for abiotic dissolution of plagioclase (23.1 ± 2.5 kcal/mol) and olivine (21.3 ± 2.7 kcal/mol) are similar to those measured in the laboratory, and are roughly double those measured from samples taken underneath lichen. Abiotic weathering rates appear to be proportional to rainfall. Dissolution of plagioclase and olivine underneath lichen is far more sensitive to rainfall.

Brady, Patrick V.; Dorn, Ronald I.; Brazel, Anthony J.; Clark, James; Moore, Richard B.; Glidewell, Tiffany

1999-10-01

124

Evaluation of pressure extracted from NCEP and CMC global numerical weather prediction models against in-situ and GPT pressure  

NASA Astrophysics Data System (ADS)

An earlier investigation by Urquhart et al (2011) demonstrated that ray traced hydrostatic zenith delays from NCEP's Re-Analysis I (NCEP) dataset proved to exhibit higher variability when compared to those from the Canadian Meteorological Centre's (CMC) Global Deterministic Prediction System (GDPS) and the European Centre for Medium Range Weather Forecasting (ECMWF). This investigation expands on the original by analyzing the variation of the zenith hydrostatic delay (as ray traced through the NWP) and the extracted pressure at the surface for 35 IGS reference stations for the entire year of 2010. Two NWP's were selected, NCEP's Re-Analysis I and CMC's GDPS. NCEP was selected since it forms the basis for the UNB-VMF1 service, and CMC's GDPS was selected due to availability. Both models have global coverage, but NCEP's grid resolution is 2.5 x 2.5 degrees as compared to CMC's (GDPS) 0.6 x 0.6 degrees. The location within the NWP is defined by the location of the IGS reference stations. The position of the reference stations are defined by the IGS weekly solutions where week 52's coordinate values for the year 2010 were used. The height was then adjusted by the defined meteorological sensor offset as defined the IGS stations's respective log. The investigation is based on the following comparisons: 1. Extracted Pressure from the NWP (NCEP and CMC (GDPS)) compared to measured pressure from the site, and also from pressure derived from GPT model. 2. Raytraced hydrostatic zenith delay compared to the Saastamoinen hydrostatic zenith computed from the measured site pressure. Results indicate good agreement between pressure extracted from the NWP and in-situ pressure and larger differences with respect to GPT.

McAdam, M.; Chai, N.; Santos, M. C.

2012-12-01

125

Observational and theoretical studies of the evolving structure of baroclinic waves: Attractor dynamics of global weather systems  

NASA Technical Reports Server (NTRS)

Significant progress was made in developing a six-component dry model of mid-latitude baroclinic wave evolution, and a ten-component moist model. These models include representations of airflow over mountians and non-adiabatic processes. As a first step, the properties of a reduced, three component, baroclinic system are studied. The classical baroclinic stability criteria emerge as the properties of one of the three equilibria admitted, with the remaining two equilibria forming the attractor region for the observed weather activity. Passive tracer evolution in a baroclinic wave was studied. A model in which only constituents trapped within low atmospheric levels are considered, has been extended to include the possibility for fluxes into the upper levels of the atmosphere. The reported results for the lower levels achieved previously are shown to be qualitatively similar to those obtained by these new calculations in which the vertical flux constraint is removed. An extensive study of an 8-year record of global outgoing longwave radiation for the Northern Hemisphere reveals that blocking events exhibit only a weak signature of blocking highs, as measured by relatively low values of the ratio of the standard deviation to the mean value of the observed long wave outgoing radiation. Though present in many cases, the signature is not a strongly distinctive feature of the blocking episodes.

Saltzman, B.; Hansen, A. R.; Nagle, R. N.; Tang, C. M.

1985-01-01

126

Rivers, chemical weathering and Earth's climate  

Microsoft Academic Search

We detail the results of recent studies describing and quantifying the large-scale chemical weathering of the main types of continental silicate rocks: granites and basalts. These studies aim at establishing chemical weathering laws for these two lithologies, describing the dependence of chemical weathering on environmental parameters, such as climate and mechanical erosion. As shown within this contribution, such mathematical laws

Bernard Dupré; Céline Dessert; Priscia Oliva; Yves Goddéris; Jérôme Viers; Louis François; Romain Millot; Jérôme Gaillardet

2003-01-01

127

Major ion chemistry in the headwaters of the Yamuna river system:. Chemical weathering, its temperature dependence and CO 2 consumption in the Himalaya  

NASA Astrophysics Data System (ADS)

The Yamuna river and its tributaries in the Himalaya constitute the Yamuna River System (YRS). The YRS basin has a drainage area and discharge comparable in magnitude to those of the Bhagirathi and the Alaknanda rivers, which merge to form the Ganga at the foothills of the Himalaya. A detailed geochemical study of the YRS was carried out to determine: (i) the relative significance of silicate, carbonate and evaporite weathering in contributing to its major ion composition; (ii) CO 2 consumption via silicate weathering; and (iii) the factors regulating chemical weathering of silicates in the basin. The results show that the YRS waters are mildly alkaline, with a wide range of TDS, ˜32 to ˜620 mg l-1. In these waters, the abundances of Ca, Mg and alkalinity, which account for most of TDS, are derived mainly from carbonates. Many of the tributaries in the lower reaches of the Yamuna basin are supersaturated with calcite. In addition to carbonic acid, sulphuric acid generated by oxidation of pyrites also seems to be supplying protons for chemical weathering. Silicate weathering in YRS basin contributes, on average, ˜25% (molar basis) of total cations on a basin wide scale. Silicate weathering, however, does not seem to be intense in the basin as evident from low Si/(Na*+K) in the waters, ˜1.2 and low values of chemical index of alteration (CIA) in bed sediments, ˜60. CO 2 drawdown resulting from silicate weathering in the YRS basin in the Himalaya during monsoon ranges between (4 to 7) × 10 5 moles km -2 y -1. This is higher than that estimated for the Ganga at Rishikesh for the same season. The CO 2 consumption rates in the Yamuna and the Ganga basins in the Himalaya are higher than the global average value, suggesting enhanced CO 2 drawdown in the southern slopes of the Himalaya. The impact of this enhanced drawdown on the global CO 2 budget may not be pronounced, as the drainage area of the YRS and the Ganga in the Himalaya is small. The CO 2 drawdown by silicates in the YRS basin is marginally higher than the reported values of CO 2 release from oxidation of organic rich sediments, estimated using Re as a proxy. This comparison shows the need to constrain CO 2 sources and sinks better to balance its budget in a regional scale. The results also show that silicate weathering rate in the YRS basin is ˜10 mm ky -1 and on the Ganga basin, it is ˜5 mm ky -1, which are several times lower than the carbonate weathering rates. The significantly higher silicate weathering rate observed in the YRS basin seems to be governed by rapid physical erosion in this region. The apparent activation energy for overall silicate weathering in the YRS basin, derived from Na* and Si concentrations and water temperature, ranges from ˜50 to 80 kJ mol -1. These values are comparable to those reported for granitoid weathering in natural watersheds and feldspar weathering in laboratory experiments. This study brings to light the sources contributing to major ions, enhanced chemical weathering rates in the Yamuna River Basin and interdependence of silicate weathering on physical erosion and temperature.

Dalai, T. K.; Krishnaswami, S.; Sarin, M. M.

2002-10-01

128

The Irrotational and Rotational Kinetic Energy Balance in Isentropic Coordinates during the Global Weather Experiment Boreal Winter.  

NASA Astrophysics Data System (ADS)

Analysis of the irrotational and rotational kinetic energy balance employing isentropic transport equations was conducted for the Global Weather Experiment boreal winter (December 1978 to February 1979) using ECMWF Main IIIb data. The purpose of this research was to investigate the relation between the global distribution of heat sources and sinks, thermally forced isentropic mass circulations, and the maintenance of the planetary circulation kinetic energy balance. By partitioning kinetic energy into irrotational and rotational components, the direct effect of heat sources and sinks is coupled to irrotational kinetic energy generation. Conversion between irrotational and rotational kinetic energy is studied and frictional dissipation is estimated by the residual method. The analysis reveals two primary systems for kinetic energy generation by thermally forced mass circulations. In the global system, monsoonal mass circulations in upper isentropic layers of the troposphere, forced by Southern Hemisphere tropical heat sources and polar heat sinks, generate irrotational kinetic energy which is concomitantly transformed to rotational kinetic energy, and maintains the planetary scale subtropical jets against frictional dissipation. Horizontal and vertical variations of irrotational kinetic energy generation for the subtropical jets results from variations of the vertical distribution of tropical heating which reflects the surface equivalent potential temperature distribution. The other system for irrotational kinetic energy generation occurs in isentropic layers beneath 300 ^circK in the Northern Hemisphere extratropics. In this system, irrotational kinetic energy generation is coupled with thermally forced circulations resulting from oceanic heat sources in extratropical cyclone circulations and continental and polar heat sinks by radiational cooling. A substantial fraction of irrotational kinetic energy is frictionally dissipated without being transformed to rotational kinetic energy because irrotational kinetic energy generation occurs mainly in the planetary boundary layer of extratropical circulations. The results of this study are consistent with regard to available potential energy generation in midlatitude storms with heating occurring at higher pressure and infrared cooling occurring at lower pressure on isentropic surfaces. An implication of these results is that oceanic heat transport and latent and sensible heat flux to the atmosphere are important for the maintenance of the atmospheric circulation below 300^circK.

Silberberg, Steven Richard

129

Friends of the Earth International Climate Change Briefing INDICATIONS OF CLIMATE CHANGE - RECENT EXTREME GLOBAL WEATHER EVENTS \\  

Microsoft Academic Search

th century record breaking temperatures and a run of extreme weather events rang the alarm bells. The trend is continuing into the 21 st century and this briefing catalogues some of the extreme weather events that have occurred during the last few months, along with signs in the environment that our climate is really changing.

WEATHER EXTREMES

130

Physical and chemical weathering  

NASA Astrophysics Data System (ADS)

Physical and chemical weathering processes that might be important on Mars are reviewed, and the limited observations, including relevant Viking results and laboratory simulations, are summarized. Physical weathering may have included rock splitting through growth of ice, salt or secondary silicate crystals in voids. Chemical weathering probably involved reactions of minerals with water, oxygen, and carbon dioxide, although predicted products vary sensitively with the abundance and physical form postulated for the water. On the basis of kinetics data for hydration of rock glass on earth, the fate of weathering-rind formation on glass-bearing Martian volcanic rocks is tentatively estimated to have been on the order of 0.1 to 4.5 cm/Gyr; lower rates would be expected for crystalline rocks.

Gooding, James L.; Arvidson, Raymond E.; Zolotov, Mikhail Iu.

131

The role of a silicate pump in driving new production  

Microsoft Academic Search

In the past, the importance of silicate as a limiting nutrient for new production in the ocean, and in determining global productivity and carbon budgets, has been relegated to the lower ranks compared to the role of nitrogen and, more recently, iron. This paper describes a “silicate pump” that acts in diatom-dominated communities to enhance the loss of silicate from

Richard C. Dugdale; Frances P. Wilkerson; Hans J. Minas

1995-01-01

132

Steady- and non-steady-state carbonate-silicate controls on atmospheric CO2  

USGS Publications Warehouse

Two contrasting hypotheses have recently been proposed for the past long-term relation between atmospheric CO2 and the carbonate-silicate geochemical cycle. One approach (Berner, 1990) suggests that CO2 levels have varied in a manner that has maintained chemical weathering and carbonate sedimentation at a steady state with respect to tectonically controlled decarbonation reactions. A second approach (Raymo et al., 1988), applied specificlly to the late Cenozoic, suggests a decrease in CO2 caused by an uplift-induced increase in chemical weathering, without regard to the rate of decarbonation. According to the steady-state (first) hypothesis, increased weathering and carbonate sedimentation are generally associated with increasing atmospheric CO2, whereas the uplift (second) hypothesis implies decreasing CO2 under the same conditions. An ocean-atmosphere-sediment model has been used to assess the response of atmospheric CO2 and carbonate sedimentation to global perturbations in chemical weathering and decarbonation reactions. Although this assessment is theoretical and cannot yet be related to the geologic record, the model simulations compare steady-state and non-steady-state carbonate-silicate cycle response. The e-fold response time of the 'CO2-weathering' feedback mechanism is between 300 and 400 ka. The response of carbonate sedimentation is much more rapid. These response times provide a measure of the strength of steady-state assumptions, and imply that certain systematic relations are sustained throughout steady-state and non-steady-state scenarios for the carbonate-silicate cycle. The simulations suggest that feedbacks can maintain the system near a steady state, but that non-steady-state effects may contribute to long-term trends. The steady-state and uplift hypotheses are not necessarily incompatible over time scales of a few million years. ?? 1991.

Sundquist, E. T.

1991-01-01

133

Space Weather: Welcome, SEC  

NSDL National Science Digital Library

This video presentation welcomes the Space Environment Center (SEC) to the National Weather Service (NWS) as an operational entity of the National Centers for Environmental Prediction (NCEP) family. Describing the ways in which space weather affects global communications and power resources, it demonstrates the importance of space weather forecasting as a part of the NWS family of services. With the inclusion of SEC, the NWS now provides environmental understanding from the sun to the sea.

Spangler, Tim

2005-01-11

134

Continental weathering following a Cryogenian glaciation: Evidence from calcium and magnesium isotopes  

NASA Astrophysics Data System (ADS)

A marked ocean acidification event and elevated atmospheric carbon dioxide concentrations following the extreme environmental conditions of the younger Cryogenian glaciation have been inferred from boron isotope measurements. Calcium and magnesium isotope analyses offer additional insights into the processes occurring during this time. Data from Neoproterozoic sections in Namibia indicate that following the end of glaciation the continental weathering flux transitioned from being of mixed carbonate and silicate character to a silicate-dominated one. Combined with the effects of primary dolomite formation in the cap dolostones, this caused the ocean to depart from a state of acidification and return to higher pH after climatic amelioration. Differences in the magnitude of stratigraphic isotopic changes across the continental margin of the southern Congo craton shelf point to local influences modifying and amplifying the global signal, which need to be considered in order to avoid overestimation of the worldwide chemical weathering flux.

Kasemann, Simone A.; Pogge von Strandmann, Philip A. E.; Prave, Anthony R.; Fallick, Anthony E.; Elliott, Tim; Hoffmann, Karl-Heinz

2014-06-01

135

The global control of silicate weathering rates and the coupling with physical erosion: new insights from rivers of the Canadian Shield  

Microsoft Academic Search

The chemical evolution of the surface of the Earth is controlled by the interaction of rainwaters, the atmosphere and the continental crust. That is the main reason why the knowledge of the parameters that control chemical denudation on Earth is of crucial importance. We report chemical and isotopic analyses for river waters from the Canadian Shield in order to estimate

Romain Millot; Jérôme Gaillardet; Bernard Dupré; Claude Jean Allègre

2002-01-01

136

Weather Forecasting  

NSDL National Science Digital Library

This activity is designed to give students an understanding of how to forecast weather and how to use weather reports for their personal benefit. They will be able to tell what weather is, read weather instruments, understand basic cloud formations in relation to the weather, and make forecasts for two days in advance.

137

COST Action ES1206 : Advanced Global Navigation Satellite Systems Tropospheric Products for Monitoring Severe Weather Events and Climate (GNSS4SWEC)  

NASA Astrophysics Data System (ADS)

Global Navigation Satellite Systems (GNSS) have revolutionised positioning, navigation, and timing, becoming a common part of our everyday life. Aside from these well-known civilian and commercial applications, GNSS is now an established atmospheric observing system which can accurately sense water vapour, the most abundant greenhouse gas, accounting for 60-70% of atmospheric warming. Severe weather forecasting is challenging, in part due to the high temporal and spatial variation of atmospheric water vapour. Water vapour is under-sampled in the current meteorological and climate observing systems, obtaining and exploiting more high-quality humidity observations is essential to weather forecasting and climate monitoring. The new COST Action, ES1206, will address new and improved capabilities from con-current developments in both the GNSS and meteorological communities. For the first time, the synergy of the three GNSS systems (GPS, GLONASS and Galileo) will be used to develop new, advanced tropospheric products, exploiting the full potential of multi-GNSS water vapour estimates on a wide range of temporal and spatial scales, from real-time monitoring and forecasting of severe weather, to climate research. In addition the Action will promote the use of meteorological data in GNSS positioning, navigation, and timing services. The Action will stimulate knowledge transfer and data sharing throughout Europe.

Jones, Jonathan; Guerova, Guergana; Dousa, Jan; de Haan, Siebren; Bock, Olivier; Dick, Galina; Pottiaux, Eric; Pacione, Rosa

2014-05-01

138

Weather assessment and forecasting  

NASA Technical Reports Server (NTRS)

Data management program activities centered around the analyses of selected far-term Office of Applications (OA) objectives, with the intent of determining if significant data-related problems would be encountered and if so what alternative solutions would be possible. Three far-term (1985 and beyond) OA objectives selected for analyses as having potential significant data problems were large-scale weather forecasting, local weather and severe storms forecasting, and global marine weather forecasting. An overview of general weather forecasting activities and their implications upon the ground based data system is provided. Selected topics were specifically oriented to the use of satellites.

1977-01-01

139

Fair weather atmospheric electricity  

NASA Astrophysics Data System (ADS)

Not long after Franklin's iconic studies, an atmospheric electric field was discovered in "fair weather" regions, well away from thunderstorms. The origin of the fair weather field was sought by Lord Kelvin, through development of electrostatic instrumentation and early data logging techniques, but was ultimately explained through the global circuit model of C.T.R. Wilson. In Wilson's model, charge exchanged by disturbed weather electrifies the ionosphere, and returns via a small vertical current density in fair weather regions. New insights into the relevance of fair weather atmospheric electricity to terrestrial and planetary atmospheres are now emerging. For example, there is a possible role of the global circuit current density in atmospheric processes, such as cloud formation. Beyond natural atmospheric processes, a novel practical application is the use of early atmospheric electrostatic investigations to provide quantitative information on past urban air pollution.

Harrison, R. G.

2011-06-01

140

Weather Watch  

ERIC Educational Resources Information Center

Suggests a number of ways in which Federal Aviation Agency weather report printouts can be used in teaching the weather section of meteorology. These weather sequence reports can be obtained free of charge at most major airports. (JR)

Bratt, Herschell Marvin

1973-01-01

141

Differences Between Climate and Weather  

NSDL National Science Digital Library

In this activity, students collect weather data over several days or weeks, graph temperature data, and compare the temperature data collected with long-term climate averages from where they live. Understanding the difference between weather and climate and interpreting local weather data are important first steps to understanding larger-scale global climate changes.

Research, National C.

142

Reconnaissance of Field Sites for the Study of Chemical Weathering on the Guayana Shield, South America  

SciTech Connect

Despite the fact that chemical weathering of silicate rocks plays an important role in the draw-down of CO{sub 2} over geologic time scales (Berner and Berner, 1996), the overall controls on the rate of chemical weathering are still not completely understood. Lacking a mechanistic understanding of these controls, it remains difficult to evaluate a hypothesis such as that presented by Raymo and Ruddiman (1992), who suggested that enhanced weathering and CO{sub 2} draw-down resulting from the uplift of the Himalayas contributed to global cooling during the Cenozoic. At an even more fundamental level, the three to four order of magnitude discrepancy between laboratory and field weathering rates is still unresolved (White et al., 1996). There is as yet no comprehensive, mechanistic model for silicate chemical weathering that considers the coupled effects of precipitation, vadose zone flow, and chemical reactions. The absence of robust process models for silicate weathering and the failure to resolve some of these important questions may in fact be related-the controls on the overall rates of weathering cannot be understood without considering the weathering environment as one in which multiple, time-dependent chemical and physical processes are coupled (Malmstrom, 2000). Once chemical weathering is understood at a mechanistic process level, the important controls on chemical weathering (physical erosion, temperature, precipitation) can be folded into larger scale models tracking the global carbon cycle. Our goal in this study was to carry out the preliminary work needed to establish a field research site for chemical weathering om the Cuayana Shield in South America. The Guayana Shield is a Precambrian province greater than 1.5 billion years old covering portions of Venezuela, Guyana (the country), Surinam, French Guiana, and Brazil (Figure 1). More important than the age of the rocks themselves, however, is the age of the erosion surface developed on the Shield, with estimates ranging as old as 65 million years. Preserved mostly in highlands, this very old erosion surface represents an end-member site where physical erosion has been significantly slower than the rate of chemical weathering. Much of the Shield is also noteworthy for the fact that chemical weathering is still occurring today, thus offering the chance to study a system in which a present day weathering regime is accompanied by an integrated weathering record over millions of years (Soler and Lasaga, 2000). If rates of chemical weathering can be determined for this very old weathering system where physical erosion is minor, they can then be compared with rates determined from sites with similar annual temperatures and rainfall, but much higher physical erosion rates. Comparative studies of this kind can provide a parameterization of chemical weathering rates as a function of physical erosion and tectonic uplift that can be used in global models for the carbon cycle.

Steefell, C I

2003-02-01

143

Lithium isotope evidence for enhanced weathering during Oceanic Anoxic Event 2  

NASA Astrophysics Data System (ADS)

The Ocean Anoxic Event 2 (OAE2) about 93.5 million years ago was marked by high atmospheric CO2 concentration, rapid global warming and marine anoxia and euxinia. The event lasted for about 440,000 years and led to habitat loss and mass extinction. The marine anoxia is thought to be linked to enhanced biological productivity, but it is unclear what triggered the increased production and what allowed the subsequent rapid climate recovery. Here we use lithium isotope measurements from carbonates spanning the interval including OAE2 to assess the role of silicate weathering. We find the lightest values of the Li isotope ratio (?7Li) during OAE2, indicating high levels of weathering--and therefore atmospheric CO2 removal--which we attribute to an enhanced hydrological cycle. We use a geochemical model to simulate the evolution of ?7Li and the Ca, Sr and Os isotope tracers. Our simulations suggest a scenario in which the eruption of a large igneous province led to high atmospheric CO2 concentrations and rapid global warming, which initiated OAE2. The simulated warming was accompanied by a roughly 200,000 year pulse of accelerated weathering of mafic silicate rocks, which removed CO2 from the atmosphere. The weathering also delivered nutrients to the oceans that stimulated primary productivity. We suggest that this process, together with the burial of organic carbon, allowed the rapid recovery and stabilization from the greenhouse state.

Pogge von Strandmann, Philip A. E.; Jenkyns, Hugh C.; Woodfine, Richard G.

2013-08-01

144

Sulfuric acid as an agent of carbonate weathering constrained by ?13C DIC: Examples from Southwest China  

NASA Astrophysics Data System (ADS)

Rock weathering by carbonic acid is thought to play an important role in the global carbon cycle because it can geologically sequestrate atmospheric CO 2. Current model of carbon cycle evolution usually assumes that carbonic acid is the major weathering agent and that other acids are not important. Here, we use carbon isotopic evidence and water chemistry of springs and rivers from the Beipanjiang River basin (Guizhou Province, Southwest China) to demonstrate that sulfuric acid is also an important agent of rock weathering. The ?13C of dissolved inorganic carbon (DIC) in the water samples ranges from - 13.1‰ to - 2.4‰, and correlates negatively to [HCO 3-]/([Ca 2+] + [Mg 2+]) ratios and positively to [SO 42-]/([Ca 2+] + [Mg 2+]) ratios. These relationships are interpreted as mixing diagrams between two reactions of carbonate weathering, using carbonic acid and sulfuric acid as a proton donor, respectively. Mixing proportions show that around 42% of the divalent cations in the spring water from Guizhou are originated from the interaction between carbonate minerals and sulfuric acid. It is shown that 40% of this sulfuric acid is derived from the atmosphere and has an anthropogenic origin. The remaining 60% are derived from the oxidative weathering of sulfide minerals in sedimentary rocks. Our results show the positive action of sulfuric acid on the chemical weathering of carbonate. Particularly, we show that sulfuric acid generated by coal combustion has increased by almost 20% the weathering rates of carbonate in Southwest China. This is a clear evidence that human activities are changing the weathering rates of rocks and demonstrates a negative feedback on the acidification of the ocean by greenhouse gases. Because of the involvement of sulfuric acid in weathering reactions, 63% of the alkalinity exported by rivers is derived from carbonate, instead of 50% when atmospheric CO 2 is the only acid involved in chemical weathering of carbonate. In the Guizhou Province, the weathering of carbonate is thus, at least transiently, a net source of CO 2 to the atmosphere. When extrapolated at global scale, sulfuric acid-induced carbonate weathering could counterbalance a significant part of the CO 2 consumed by silicate weathering. This paper highlights the competition between silicate weathering by carbonic acid and carbonate weathering by sulfuric acid for the regulation of the atmospheric CO 2 level.

Li, Si-Liang; Calmels, Damien; Han, Guilin; Gaillardet, Jérôme; Liu, Cong-Qiang

2008-06-01

145

Approach to Integrate Global-Sun Models of Magnetic Flux Emergence and Transport for Space Weather Studies  

NASA Astrophysics Data System (ADS)

The Sun lies at the center of space weather and is the source of its variability. The primary input to coronal and solar wind models is the activity of the magnetic field in the solar photosphere. Recent advancements in solar observations and numerical simulations provide a basis for developing physics-based models for the dynamics of the magnetic field from the deep convection zone of the Sun to the corona with the goal of providing robust near real-time boundary conditions at the base of space weather forecast models. The goal is to develop new strategic capabilities that enable characterization and prediction of the magnetic field structure and flow dynamics of the Sun by assimilating data from helioseismology and magnetic field observations into physics-based realistic magnetohydrodynamics (MHD) simulations. The integration of first-principle modeling of solar magnetism and flow dynamics with real-time observational data via advanced data assimilation methods is a new, transformative step in space weather research and prediction. This approach will substantially enhance an existing model of magnetic flux distribution and transport developed by the Air Force Research Lab. The development plan is to use the Space Weather Modeling Framework (SWMF) to develop Coupled Models for Emerging flux Simulations (CMES) that couples three existing models: (1) an MHD formulation with the anelastic approximation to simulate the deep convection zone (FSAM code), (2) an MHD formulation with full compressible Navier-Stokes equations and a detailed description of radiative transfer and thermodynamics to simulate near-surface convection and the photosphere (Stagger code), and (3) an MHD formulation with full, compressible Navier-Stokes equations and an approximate description of radiative transfer and heating to simulate the corona (Module in BATS-R-US). CMES will enable simulations of the emergence of magnetic structures from the deep convection zone to the corona. Finally, a plan will be summarized on the development of a Flux Emergence Prediction Tool (FEPT) in which helioseismology-derived data and vector magnetic maps are assimilated into CMES that couples the dynamics of magnetic flux from the deep interior to the corona.

Mansour, N. N.; Wray, A. A.; Mehrotra, P.; Arge, C. N.; Henney, C.; Manchester, W.; Godinez, H. C.; Koller, J.; Kosovichev, A. G.; Scherrer, P. H.; Zhao, J.; Stein, B.; Duvall, T.; Fan, Y.

2013-12-01

146

Approach to Integrate Global-Sun Models of Magnetic Flux Emergence and Transport for Space Weather Studies  

NASA Technical Reports Server (NTRS)

The Sun lies at the center of space weather and is the source of its variability. The primary input to coronal and solar wind models is the activity of the magnetic field in the solar photosphere. Recent advancements in solar observations and numerical simulations provide a basis for developing physics-based models for the dynamics of the magnetic field from the deep convection zone of the Sun to the corona with the goal of providing robust near real-time boundary conditions at the base of space weather forecast models. The goal is to develop new strategic capabilities that enable characterization and prediction of the magnetic field structure and flow dynamics of the Sun by assimilating data from helioseismology and magnetic field observations into physics-based realistic magnetohydrodynamics (MHD) simulations. The integration of first-principle modeling of solar magnetism and flow dynamics with real-time observational data via advanced data assimilation methods is a new, transformative step in space weather research and prediction. This approach will substantially enhance an existing model of magnetic flux distribution and transport developed by the Air Force Research Lab. The development plan is to use the Space Weather Modeling Framework (SWMF) to develop Coupled Models for Emerging flux Simulations (CMES) that couples three existing models: (1) an MHD formulation with the anelastic approximation to simulate the deep convection zone (FSAM code), (2) an MHD formulation with full compressible Navier-Stokes equations and a detailed description of radiative transfer and thermodynamics to simulate near-surface convection and the photosphere (Stagger code), and (3) an MHD formulation with full, compressible Navier-Stokes equations and an approximate description of radiative transfer and heating to simulate the corona (Module in BATS-R-US). CMES will enable simulations of the emergence of magnetic structures from the deep convection zone to the corona. Finally, a plan will be summarized on the development of a Flux Emergence Prediction Tool (FEPT) in which helioseismology-derived data and vector magnetic maps are assimilated into CMES that couples the dynamics of magnetic flux from the deep interior to the corona.

Mansour, Nagi N.; Wray, Alan A.; Mehrotra, Piyush; Henney, Carl; Arge, Nick; Godinez, H.; Manchester, Ward; Koller, J.; Kosovichev, A.; Scherrer, P.; Zhao, J.; Stein, R.; Duvall, T.; Fan, Y.

2013-01-01

147

Cockpit weather information (CWIN) system  

Microsoft Academic Search

The objective of this advanced concept, Cockpit Weather Information System (CWIN), is to develop an aeronautical system that delivers real-time graphical weather information with global-coverage to the flight deck of an aircraft via a satellite communications system (SATCOM)\\/global positioning system (GPS)

Jeffrey C. Tu

1997-01-01

148

Weather Basics  

NSDL National Science Digital Library

Students are introduced to the basics of the Earth's weather. Concepts include fundamental causes of common weather phenomena such as temperature changes, wind, clouds, rain and snow. The different factors that affect the weather and the instruments that measure weather data are also addressed.

Integrated Teaching And Learning Program

149

Weather Forecasting  

NSDL National Science Digital Library

Students consider how weather forecasting plays an important part in their daily lives. They learn about the history of weather forecasting â from old weather proverbs to modern forecasting equipment â and how improvements in weather technology have saved lives by providing advance warning of natural hazards.

Integrated Teaching And Learning Program

150

Severe Weather  

NSDL National Science Digital Library

Educating the public about safety issues related to severe weather is part of the National Oceanic and Atmospheric Administration's (NOAA) mission. This month's insert, Severe Weather, has been created by NOAA to help educate the public about hazardous weather conditions. The four types of severe weather highlighted in this poster are hurricanes, flash floods, lightning, and tornadoes.

Forde, Evan B.

2004-04-01

151

Severe Weather  

ERIC Educational Resources Information Center

Educating the public about safety issues related to severe weather is part of the National Oceanic and Atmospheric Administration's (NOAA) mission. This article deals with a poster entitled, "Severe Weather," that has been created by NOAA to help educate the public about hazardous weather conditions. The four types of severe weather highlighted in…

Forde, Evan B.

2004-01-01

152

Severe Weather  

ERIC Educational Resources Information Center

Educating the public about safety issues related to severe weather is part of the National Oceanic and Atmospheric Administration's (NOAA) mission. This month's insert, Severe Weather, has been created by NOAA to help educate the public about hazardous weather conditions. The four types of severe weather highlighted in this poster are hurricanes,…

Forde, Evan B.

2004-01-01

153

Air temperature-driven CO2 consumption by rock weathering at short timescales: Evidence from a Holocene lake sediment record  

NASA Astrophysics Data System (ADS)

The role that air temperature plays in the interaction between atmospheric CO2 levels and continental rock weathering at relatively short time scales is still a matter of debate. Laboratory studies reveal a strong dependence of mineral dissolution on temperature, but field comparisons among watersheds under different climate conditions often indicate correlations with other environmental factors. Using a paleolimnological approach, here we show that there has been an extremely good coupling between rock weathering, water alkalinity (CO2 consumption), and air temperature during the last 10,000 years at sub-millennial time scales in a small watershed of silicate bedrock and scarce vegetation. The calculation of apparent activation energy for the weathering reaction (as a means to describe the temperature dependence of the process) provides a value (Ea = 67 ± 7 kJ mol-1) that is comparable to those found for silicate rocks similar to those in the watershed in laboratory experiments and some field studies. Our results provide evidence that regulatory constraints between air temperature, atmospheric CO2 and silicate rock weathering can be fine-tuned at geological timescales and may not be negligible in the current context of global change.

Catalan, Jordi; Pla-Rabés, Sergi; García, Joan; Camarero, Lluís

2014-07-01

154

Severe Weather  

NSDL National Science Digital Library

Meteorologists disagree as to what constitutes severe weather. However, most concur that thunderstorms, tornadoes, and hurricanes, all considered to be "convective" weather, fit the definition of severe weather, which is a weather condition likely to cause hardship. This science guide will explore each of the three weather phenomena. By virtue of their locations, most students are familiar with at least one of the three severe weather events. Students who tour the web sites will have an opportunity to make connections between the familiar and the perhaps less understood weather events.

National Science Teachers Association (NSTA)

2005-04-01

155

Winter Weather  

NSDL National Science Digital Library

This project explores factors that help create severe winter weather. An interactive simulation provides hands-on experience, followed by guiding questions and resource exploration. Weather affects our everyday lives. Some days it's sunny and some days its not. The years weather is split up into seasons. 1. What are the four seasons? 2. What kind of weather do you see in the summer? 3. What kind of weather is unique to winter? 4. ...

Bellows, Mrs.

2009-09-28

156

Global three-dimensional MHD simulation of a space weather event: CME formation, interplanetary propagation, and interaction with the magnetosphere  

NASA Astrophysics Data System (ADS)

A parallel adaptive mesh refinement (AMR) finite-volume scheme for predicting ideal MHD flows is used to simulate the initiation, structure, and evolution of a coronal mass ejection (CME) and its interaction with the magnetosphere-ionosphere system. The simulated CME is driven by a local plasma density enhancement on the solar surface with the background initial state of the corona and solar wind represented by a newly devised ``steady state'' solution. The initial solution has been constructed to provide a reasonable description of the time-averaged solar wind for conditions near solar minimum: (1) the computed magnetic field near the Sun possesses high-latitude polar coronal holes, closed magnetic field flux tubes at low latitudes, and a helmet streamer structure with a neutral line and current sheet; (2) the Archimedean spiral topology of the interplanetary magnetic field is reproduced; (3) the observed two-state nature of the solar wind is also reproduced with the simulation yielding fast and slow solar wind streams at high and low latitudes, respectively; and (4) the predicted solar wind plasma properties at 1 AU are consistent with observations. Starting with the generation of a CME at the Sun, the simulation follows the evolution of the solar wind disturbance as it evolves into a magnetic cloud and travels through interplanetary space and subsequently interacts with the terrestrial magnetosphere-ionosphere system. The density-driven CME exhibits a two-step release process, with the front of the CME rapidly accelerating following the disruption of the near-Sun closed magnetic field line structure and then moving at a nearly constant speed of ~560 km/s through interplanetary space. The CME also produces a large magnetic cloud (>100RS across) characterized by a magnetic field that smoothly rotates northward and then back again over a period of ~2 days at 1 AU. The cloud does not contain a sustained period with a strong southward component of the magnetic field, and, as a consequence, the simulated CME is somewhat ineffective in generating strong geo-magnetic activity at Earth. Nevertheless, the simulation results illustrate the potential, as well as current limitations, of the MHD-based space weather model for enhancing the understanding of coronal physics, solar wind plasma processes, magnetospheric physics, and space weather phenomena. Such models will provide the foundation for future, more comprehensive space weather prediction tools.

Groth, Clinton P. T.; De Zeeuw, Darren L.; Gombosi, Tamas I.; Powell, Kenneth G.

2000-11-01

157

The impact of tropical wind data on the analysis and forcasts of the GLA GCM for the global weather experiment  

NASA Technical Reports Server (NTRS)

It is well-known that divergent wind estimates are much more dependent upon the analysis system than are estimates of the rotational wind. This conclusion is supported in recent analyses of FGGE SOP1 data produced by the Goddard Laboratory for Atmospheres (GLA), the Geophysical Fluid Dynamics Laboratory (GFDL) and the European Center for Medium Range Weather Forecasting (ECMWF). These analyses differ in the forecast models that are used for the four-dimensional assimilation, in the data rejection criteria, and, to a certain extent, in the data density. Because the final divergent wind is a product of both model constraints and observation, it is relevant to inquire how much of each goes into the final product. We presently investigate this question through a systematic analysis of tropical data that are sampled at different densities by the GLA GCM.

Paegle, Jan; Baker, W. E.

1985-01-01

158

Weather Here and There  

NSDL National Science Digital Library

The Global Education Project of the Resource for Science Education Program offers the Weather Here and There educational unit. The Web site consists of six lessons geared for students in grades four through six that cover everything from characteristics of the Earth's atmosphere to forecasting the weather. Each lesson contains the objectives, materials, background information, vocabulary, evaluation, etc. needed to easily prepare and complete each.

1995-01-01

159

Weather and Climate  

NSDL National Science Digital Library

This site features visual resources and supporting data that illustrate the relationship between weather and climate. Resources are divided by topic including climate resources, weather forecasting, warnings and data, and evidence for global warming. Visualizations and data sets include GIS-based animated maps, static maps, simple animations, and links to real-time stream gauge data. This site provides an array of visual resources that help demonstrate the difference between weather and climate and may be incorporated into lectures, labs, or other activities.

2007-04-11

160

Weathering Animation  

NSDL National Science Digital Library

Weathering is the term that describes all the processes that break down rocks in the environment near the Earth's surface. This module will help you to understand two weathering processes: mechanical and chemical.

2002-01-01

161

Spatial variations in chemical weathering and CO 2 consumption in Nepalese High Himalayan catchments during the monsoon season  

NASA Astrophysics Data System (ADS)

The major ion chemistry of the Marsyandi basin and six of its tributaries in the Nepalese Himalaya have been investigated during the monsoon months of 2002. Weekly water samples taken at 10 river monitoring stations in the Annapurna watershed over the course of 4 months provide chemical weathering data for the region at an unprecedented temporal and spatial resolution. The river chemistry of all but one basin is heavily dominated by carbonate weathering which, compared to silicate weathering, contributes 80 to 97% of the total solute load. This prevalence is due to a combination of (a) intrinsically faster dissolution kinetics of carbonates, (b) relatively high runoff and (c) glacial meltwater and low temperatures at high altitudes resulting in enhanced carbonate solubilities. Monitoring stations with headwaters in the Tethyan Sedimentary Series (TSS) are particularly carbonate-rich and slightly supersaturated with respect to calcite through half of the monsoon season. Silicate weathering in the TSS is driven largely by sulfuric acid and therefore does not contribute significantly to the drawdown of atmospheric CO 2. With respect to the tributaries in the Greater Himalayan Sequence (GHS), carbonate weathering is practically as predominant as for the TSS, in spite of the largely felsic lithology of the GHS. Relative to the TSS, the primary proton source in the GHS has shifted, with at least 80% of the protons derived from carbonic acid. Averaged over the whole field area, the CO 2 fluxes, based on silicate-derived Ca and Mg, are considerably lower than the global average. Assuming that this study area is representative of the entire range, we conclude that in situ weathering of the High Himalayas does not represent a significant sink of atmospheric carbon dioxide, despite the presence of a watershed south of the GHS that is characterized by a four times higher CO 2 consumption rate than the global average. Silicate weathering rates of all basins appear to be climate controlled, displaying a tight correlation with runoff and temperature. Given the extremely low chemical weathering under transport-limited conditions in high-altitude crystalline terrains outside of the monsoon season, this would result in virtually no chemical exhumation for 2/3 of the year in such a cold and arid climate, north of the rain shadow cast by the High Himalayas.

Wolff-Boenisch, Domenik; Gabet, Emmanuel J.; Burbank, Douglas W.; Langner, Heiko; Putkonen, Jaakko

2009-06-01

162

Weather Forecasting  

NSDL National Science Digital Library

This website, supplied by Annenberg / CPB, discusses weather satellites, Doppler radar, and additional tools forecasters use to predict the weather. Students can find a wind chill calculator along with a brief discussion of the history of forecasting and weather lore. Once you have a firm grasp on the science of weather forecasting, be sure to check out the other sections of this site, which include: "ice and snow," "our changing climate," "the water cycle," and "powerful storms."

2008-03-27

163

Weather Talk  

NSDL National Science Digital Library

Weather Talk is a primer on weather and naval meteorology. It provides a brief overview of major weather elements and is presented in a non-mathematical way, so that the reader will have a better understanding of the basic mechanisms of weather and use it to their advantage and safety in planning and carrying out their own activities. The site explains temperature, wind, pressure, atmospheric moisture, air masses and fronts, thunderstorms, tornadoes, hurricanes, and climatology.

164

Alteration Histories of the CR Chondrites II: The Weathered  

NASA Astrophysics Data System (ADS)

In GRO 03116, Fe has been mobilized to the matrix and chondrule mesostasis during Antarctic weathering. FIB/TEM shows that instead of forming ferryhydrite, Fe was incorporated into poorly crystalline silicates or originated micron and nano magnetite.

Abreu, N. M.; Colley, C. R.; Stanek, G. L.

2012-09-01

165

World Weather  

NSDL National Science Digital Library

What's going on in the world of weather? Are there storms around Sri Lanka? What about the snows of Kilimanjaro? These can be pressing questions, indeed, and the World Weather app is a great way to stay in touch with weather patterns around the globe. Users will find that they can just type in a city name to see the current weather and also zoom around the globe as they see fit. It's a remarkable addition to the world of existing weather tracking apps and is compatible with all operating systems.

Elias, Jaume S.

2014-02-20

166

Weather Watcher  

NSDL National Science Digital Library

As spring progresses, weather conditions can continue to fluctuate dramatically, something that may foil vacation plans or other outings. Keeping that in mind, visitors may do well to download the Weather Watcher application created by Mike Singer. With this application, users may automatically retrieve the current weather conditions, look through hourly forecasts, keep abreast of severe weather alerts, and take a look at weather maps for almost any city world-wide. This application is compatible with all systems running Windows 98 and above.

Singer, Mike

167

Controls on chemical weathering kinetics: Implications from modelling of stable isotope fractionations  

NASA Astrophysics Data System (ADS)

The kinetic controls on silicate chemical weathering rates are thought central to the feedback process that regulates global climate on geological time scales. However the nature and magnitude of these kinetic controls are controversial. In particular the importance of physical erosion rates is uncertain with some arguing that there is an upper limit on chemical weathering fluxes irrespective of physical erosion rates (e.g. Dixon and von Blackenburg, 2012). Others argue that it is the hydrology of catchments which determines flow path lengths and fluid residence times which are critical to chemical weathering fluxes (e.g. Maher, 2011). Understanding these physical controls is essential to predicting how chemical weathering fluxes will respond the key climatic controls. Chemical weathering fluxes are best estimated by the integrated riverine outputs from catchments as soil profiles may not integrate all the flow paths. However the interpretation of chemical weathering processes based solely on flux data is difficult, because of both the multiple processes acting and multiple phases dissolving that contribute to these fluxes. Fractionations of stable isotopes of the soluble elements including Li, Mg, Si and Ca should place additional constraints on chemical weathering processes. Here we use a simple reactive-transport model to interpret stable isotope fractionations. Although still a simplification of the natural system, this offers a much closer representation than simple batch and Rayleigh models. The isotopic fractionations are shown to be a function of the ratio of the amount of the element supplied by mineral dissolution to that lost to secondary mineral formation and the extent of reaction down the flow path. The modelling is used to interpret the evolution of dissolved Li, Mg and Si-isotope ratios in Ganges river system. The evolution of Si isotopic ratios in the rapidly eroding Himalayan catchments is distinct from that in the flood planes. Critically the extent of the isotopic fractionations is a measure of the approach of the system to chemical equilibrium, a key indicator of the temperature sensitivity of the chemical weathering rate and hence important to understanding the climate-weathering feedback. Dixon JL, & von Blanckenburg, F, (2012) Soils as pacemakers and limiters of global silicate weathering. Comptes Rendus Geoscience, 344:597-609. Maher, K (2011) The role of fluid residence time and topographic scales in determining chemical fluxes from landscapes. Earth and Planetary Science Letters, 312:48-58.

Bickle, M. J.; Tipper, E.; De La Rocha, C. L.; Galy, A.; Li, S.

2013-12-01

168

Silicate volcanism on Io  

NASA Technical Reports Server (NTRS)

This paper is mainly concerned with the nature of volcanic eruptions on Io, taking into account questions regarding the presence of silicates or sulfur as principal component. Attention is given to the generation of silicate magma, the viscous dissipation in the melt zone, thermal anomalies at eruption sites, and Ionian volcanism. According to the information available about Io, it appears that its volcanism and hence its surface materials are dominantly silicic. Several percent of volatile materials such as sulfur, but also including sodium- and potassium-rich materials, may also be present. The volatile materials at the surface are continually vaporized and melted as a result of the high rates of silicate volcanism.

Carr, M. H.

1986-01-01

169

Silicate volcanism on Io  

NASA Astrophysics Data System (ADS)

This paper is mainly concerned with the nature of volcanic eruptions on Io, taking into account questions regarding the presence of silicates or sulfur as principal component. Attention is given to the generation of silicate magma, the viscous dissipation in the melt zone, thermal anomalies at eruption sites, and Ionian volcanism. According to the information available about Io, it appears that its volcanism and hence its surface materials are dominantly silicic. Several percent of volatile materials such as sulfur, but also including sodium- and potassium-rich materials, may also be present. The volatile materials at the surface are continually vaporized and melted as a result of the high rates of silicate volcanism.

Carr, M. H.

1986-03-01

170

Has Anthropogenic Global Warming in the Arctic Contributed to Colder Winter Weather in the Northern Hemisphere Mid-latitudes?  

NASA Astrophysics Data System (ADS)

The global climate models predict that temperatures will warm the greatest in winter due to a positive feedback of increased greenhouse gases and a diminished and darker cryosphere. Furthermore, current consensus on global climate change predicts warming trends over the NH continents during boreal winter. However, recent trends in Northern Hemisphere (NH) seasonal surface temperatures diverge from these projections. For the last two decades or so, NH landmasses have experienced significant warming trends for all seasons except winter, when large-scale cooling trends exist instead. We propose a mechanism linking Arctic warming and winter continental cooling. Evidence suggests that summer and autumn Arctic warming trends are concurrent with increases in high-latitude moisture and an increase in autumnal Eurasian snow cover, which dynamically induces large-scale wintertime cooling. Understanding this counterintuitive response to radiative warming of the climate system has the potential to improve climate predictions at seasonal and longer timescales.a) JAS area-averaged (poleward of 60°N) surface temperature anomalies (°C) from NASA MERRA. b) September area-averaged (poleward of 65°N) Arctic Ocean sea ice coverage (fractional area). c) September - October vertically integrated (700-1000 hPa) and area-averaged (poleward of 60°N) specific humidity (kg m-2). d) October mean snow cover areal extent (106 km2) over the Eurasian continent from observations (black) and ensemble-mean from the historical runs of the CMIP5 model output (brown line). e) The DJF average AO index (standardized). Same-coloured dashed lines in a) - e) represent the linear trend in each index. Trends with double asterisk (**) indicate trends are significant at the p < 0.01 level.

Cohen, J. L.; Furtado, J. C.; Barlow, M. A.; Cherry, J. E.; Alexeev, V. A.

2012-12-01

171

Predicting the Weather  

NSDL National Science Digital Library

This Topic in Depth explores the science behind predicting the weather. First, the United States Search and Rescue Task Force describe the basic tools and knowledge used to create weather forecasts (1). Students can find concise, clear explanations of weather, fronts and air masses, high and low pressure, precipitation, and water vapor and humidity as well. By performing the activities presented in the second website, fourth grade students can learn about weather instruments and data collection (2). This website, produced by the Government of Saskatchewan, also explores how the weather can impact local communities. Third, Edheads offers a Macromedia Flash Player enhanced interactive module allowing students to predict the weather by examining weather maps (3 ). Through this website, users can become familiar with the concepts of warm and cold fronts, wind direction and speed, air pressure, and humidity. The fourth website, supplied by Annenberg / CPB, discusses weather satellites, Doppler radar, and additional tools forecasters use to predict the weather (4). Students can find a wind chill calculator along with a brief discussion of the history of forecasting and weather lore. Next, NOAA provides graphics for five forecast models: the ETA, the Global Forecast System (GFS), the Wave Watch III (WW3), the Nested Grid model (NGM), and the Rapid Update Cycle (RUC) (5). Outputs are available for North America, North Pacific, Western North Atlantic, and the Polar Ice Drift. Users can find links to detailed descriptions of the inputs and history of each model. Sixth, the British government's Met Office describes numerical modeling and its components (6). Students and educators can learn about the future in forecasting as well as educational opportunities with the Cooperative Program for Meteorology, Education, and Training (COMET).

172

Weather Instruments  

NSDL National Science Digital Library

This Topic in Depth discusses the variety of instruments used to collect climate and weather data. The first two websites provide simple introductions to the many weather instruments. Bethune Academy's Weather Center (1) discusses the functions of psychrometers, anemometers, weather balloons, thermometers, and barometers. The Illinois State Water Survey (2) furnishes many images of various instruments that collect data daily for legal issues, farmers, educators, students, and researchers. The third website (3), created by the Center for Improving Engineering and Science Education (CIESE), provides a classroom activity to educate users on how to build and use weather instruments. By the end of the group project, students should know all about wind vanes, rain gauges, anemometers, and thermometers. Next, the Miami Museum of Science provides a variety of activities to help students learn about the many weather instruments including wind scales and wind chimes (4). Students can learn about the wind, air pressure, moisture, and temperature. At the fifth website, the Tyson Research Center at Washington University describes the devices it uses in its research (5). At the various links, users can find out the center's many projects that utilize meteorological data such as acid rain monitoring. The sixth website, a pdf document created by Dr. John Guyton at the Mississippi State University Extension Service, provides guidance to teachers about the education of weather patterns and instruments (6). Users can find helpful information on pressure systems, humidity, cloud patterns, and much more. Next, the University of Richmond discusses the tools meteorologists use to learn about the weather (7). While providing materials about the basic tools discussed in the other websites, this site also offers information about weather satellites, radar, and computer models. After discovering the many weather instruments, users can learn about weather data output and analysis at the Next Generation Weather Lab website (8). This expansive website provides an abundance of surface data and upper air data as well as satellite and radar images for the United States.

173

Predicting Weather  

NSDL National Science Digital Library

By performing the activities presented in this website, fourth grade students can learn about weather instruments and data collection. This website, produced by the Government of Saskatchewan, also explores how the weather can impact local communities. Each activity presented here includes both objectives and assessment techniques for the lesson. Sixteen different activity suggestions provide students and teachers with ample opportunities to explore weather in the classroom.

2008-03-28

174

Weather Experiments  

NSDL National Science Digital Library

Looking for fun ways to learn about weather? Weather Wiz Kids has 39 fun weather related experiments for you to try. These experiments can be done in the classroom with your friends or even at home! Some of the experiments on the site include: tornado in a bottle, make lightning, make it rain, cloud in a bottle, what's in the wind, the Doppler Effect, and baking soda volcano.

2010-01-01

175

Precipitable water and surface humidity over global oceans from special sensor microwave imager and European Center for Medium Range Weather Forecasts  

NASA Technical Reports Server (NTRS)

Global fields of precipitable water W from the special sensor microwave imager were compared with those from the European Center for Medium Range Weather Forecasts (ECMWF) model. They agree over most ocean areas; both data sets capture the two annual cycles examined and the interannual anomalies during an ENSO episode. They show significant differences in the dry air masses over the eastern tropical-subtropical oceans, particularly in the Southern Hemisphere. In these regions, comparisons with radiosonde data indicate that overestimation by the ECMWF model accounts for a large part of the differences. As a check on the W differences, surface-level specific humidity Q derived from W, using a statistical relation, was compared with Q from the ECMWF model. The differences in Q were found to be consistent with the differences in W, indirectly validating the Q-W relation. In both W and Q, SSMI was able to discern clearly the equatorial extension of the tongues of dry air in the eastern tropical ocean, while both ECMWF and climatological fields have reduced spatial gradients and weaker intensity.

Liu, W. T.; Tang, Wenqing; Wentz, Frank J.

1992-01-01

176

Space weather  

NASA Astrophysics Data System (ADS)

Space weather is caused by conditions on the Sun and in the solar wind, the magnetosphere, ionosphere and thermosphere that can influence the performance and reliability of space-borne and ground-based technological systems and can affect human life or health. It affects man-made systems such as satellite electronics, terrestrial power grids and radio communications. This paper provides an overview of how space weather arises in the solar terrestrial system and how physical processes are able to cause space weather effects. We also discuss European perspectives and activities geared towards the possible initiation of a European Space Weather programme.

Glover, Alexi; Daly, Eamonn; Hilgers, Alain; Berghmans, David

2002-05-01

177

Thermochemistry of Silicate Speciation in Aqueous Sodium Silicate Solutions: Ionization and Polymerization of Small Silicate Ion.  

National Technical Information Service (NTIS)

The thermochemistry of simple silicate oligomers in aqueous sodium silicate solutions is rationalized by a model that qualitatively predicts equilibria among monomer, dimer, and trimer silicate structures. Unlike previous models, it incorporates the influ...

J. Yang A. V. McCormick

1993-01-01

178

Chemical weathering in a tropical watershed, Luquillo Mountains, Puerto Rico: I. Long-term versus short-term weathering fluxes  

USGS Publications Warehouse

The pristine Rio Icacos watershed in the Luquillo Mountains in eastern Puerto Rico has the fastest documented weathering rate of silicate rocks on the Earth's surface. A regolith propagation rate of 58 m Ma-1 calculated from iso-volumetric saprolite formation from quartz diorite, is comparable to the estimated denudation rate (25-50 Ma-1) but is an order of magnitude faster than the global average weathering rate (6 Ma-1). Weathering occurs in two distinct environments; plagioclase and hornblende react at the saprock interface and biotite and quartz weather in the overlying thick saprolitic regolith. These environments produce distinctly different water chemistries, with K, Mg, and Si increasing linearly with depth in saprolite porewaters and with stream waters dominated by Ca, Na, and Si. Such differences are atypical of less intense weathering in temperate watersheds. Porewater chemistry in the shallow regolith is controlled by closed-system recycling of inorganic nutrients such as K. Long-term elemental fluxes through the regolith (e.g., Si = 1.7 ?? 10-8 moles m-2 s-1) are calculated from mass losses based on changes in porosity and chemistry between the regolith and bedrock and from the age of the regolith surface (200 Ma). Mass losses attributed to solute fluxes are determined using a step-wise infiltration model which calculates mineral inputs to the shallow and deep saprolite porewaters and to stream water. Pressure heads decrease with depth in the shallow regolith (-2.03 m H2O m-1), indicating that both increasing capillary tension and graviometric potential control porewater infiltration. Interpolation of experimental hydraulic conductivities produces an infiltration rate of 1 m yr-1 at average field moisture saturation which is comparable with LiBr tracer tests and with base discharge from the watershed. Short term weathering fluxes calculated from solute chemistries and infiltration rates (e.g., Si = 1.4 ?? 10-8 moles m-2 s-1) are compared to watershed flux rates (e.g., Si = 2.7 ?? 10-8 moles m-2 s-1). Consistency between three independently determined sets of weathering fluxes imply that possible changes in precipitation, temperature, and vegetation over the last several hundred thousand years have not significantly impacted weathering rates in the Luquillo Mountains of Puerto Rico. This has important ramifications for tropical environments and global climate change. Copyright ?? 1998 Elsevier Science Ltd.

White, A. F.; Blum, A. E.; Schulz, M. S.; Vivit, D. V.; Stonestrom, D. A.; Larsen, M.; Murphy, S. F.; Eberl, D.

1998-01-01

179

Chemical Weathering in a Tropical Watershed, Luquillo Mountains, Puerto Rico: I. Long-Term Versus Short-Term Weathering Fluxes  

NASA Astrophysics Data System (ADS)

The pristine Rio Icacos watershed in the Luquillo Mountains in eastern Puerto Rico has the fastest documented weathering rate of silicate rocks on the Earth's surface. A regolith propagation rate of 58 m Ma -1, calculated from iso-volumetric saprolite formation from quartz diorite, is comparable to the estimated denudation rate (25-50 Ma -1) but is an order of magnitude faster than the global average weathering rate (6 Ma -1). Weathering occurs in two distinct environments; plagioclase and hornblende react at the saprock interface and biotite and quartz weather in the overlying thick saprolitic regolith. These environments produce distinctly different water chemistries, with K, Mg, and Si increasing linearly with depth in saprolite porewaters and with stream waters dominated by Ca, Na, and Si. Such differences are atypical of less intense weathering in temperate watersheds. Porewater chemistry in the shallow regolith is controlled by closed-system recycling of inorganic nutrients such as K. Long-term elemental fluxes through the regolith (e.g., Si = 1.7 × 10 -8 moles m -2 s -1) are calculated from mass losses based on changes in porosity and chemistry between the regolith and bedrock and from the age of the regolith surface (200 Ma). Mass losses attributed to solute fluxes are determined using a step-wise infiltration model which calculates mineral inputs to the shallow and deep saprolite porewaters and to stream water. Pressure heads decrease with depth in the shallow regolith (-2.03 m H 2O m -1), indicating that both increasing capillary tension and graviometric potential control porewater infiltration. Interpolation of experimental hydraulic conductivities produces an infiltration rate of 1 m yr -1 at average field moisture saturation which is comparable with LiBr tracer tests and with base discharge from the watershed. Short term weathering fluxes calculated from solute chemistries and infiltration rates (e.g., Si = 1.4 × 10 -8 moles m -2 s -1) are compared to watershed flux rates (e.g., Si = 2.7 × 10 -8 moles m -2 s -1). Consistency between three independently determined sets of weathering fluxes imply that possible changes in precipitation, temperature, and vegetation over the last several hundred thousand years have not significantly impacted weathering rates in the Luquillo Mountains of Puerto Rico. This has important ramifications for tropical environments and global climate change.

White, Art F.; Blum, Alex E.; Schulz, Marjorie S.; Vivit, Davison V.; Stonestrom, David A.; Larsen, Matthew; Murphy, Sheila F.; Eberl, D.

1998-01-01

180

Weather Forecasting  

NSDL National Science Digital Library

This activity (on page 2 of the PDF) is a full inquiry investigation into meteorology and forecasting. Learners will research weather folklore, specifically looking for old-fashioned ways of predicting the weather. Then, they'll record observations of these predictors along with readings from their own homemade barometer, graphing the correct predictions for analysis. Relates to linked video, DragonflyTV: Forecasting.

Twin Cities Public Television, Inc.

2005-01-01

181

Space Weather  

NASA Technical Reports Server (NTRS)

This video provides a narrated exploration of the history and affects of space weather. It includes information the earth's magnetic field, solar radiation, magnetic storms, and how solar winds affect electronics on earth, with specific information on how space weather affects space exploration in the future.

Gallagher, Dennis L.

2010-01-01

182

Weather Instruments.  

ERIC Educational Resources Information Center

This booklet presents some activities to measure various weather phenomena. Directions for constructing a weather station are included. Instruments including rain gauges, thermometers, wind vanes, wind speed devices, humidity devices, barometers, atmospheric observations, a dustfall jar, sticky-tape can, detection of gases in the air, and pH of…

Brantley, L. Reed, Sr.; Demanche, Edna L.; Klemm, E. Barbara; Kyselka, Will; Phillips, Edwin A.; Pottenger, Francis M.; Yamamoto, Karen N.; Young, Donald B.

183

Oceans, Climate and Weather  

NSDL National Science Digital Library

What is the difference between weather and climate? What do the oceans have to do with them? Weather is the day-to-day state of the atmosphere and its short-term (minutes to weeks) variation. Climate is typically described by the regional patterns of seasonal temperature and precipitation over 30 years. The averages of annual temperature, rainfall, cloud cover, and depth of frost penetration are all typical climate-related statistics. The oceans influence the worlds climate by storing solar energy and distributing it around the planet through currents and atmospheric winds.This publication is all about developing your students understandings of earths oceans and the major effect they have on climate. Understanding and interpreting local weather data and understanding the relationship between weather and climate are important first steps to understanding larger-scale global climate changes. Activities that ask students to collect and analyze local weather data as well as analyze global data can be found in the Lessons and Activities section. Analyzing and interpreting data is a major focus of this publication. Numerous data sets can be found in the Sources for Real Data section. The Background Information section and the article Tomorrows Forecast will help reinforce your own content knowledge.

Lightle, Kimberly

2006-01-01

184

Oceans, Climate, and Weather  

NSDL National Science Digital Library

This resource guide from the Middle School Portal 2 project, written specifically for teachers, provides links to exemplary resources including background information, lessons, career information, and related national science education standards. What is the difference between weather and climate? What do the oceans have to do with them? Weather is the day-to-day state of the atmosphere and its short-term (minutes to weeks) variation. Climate is typically described by the regional patterns of seasonal temperature and precipitation over 30 years. The averages of annual temperature, rainfall, cloud cover, and depth of frost penetration are all typical climate-related statistics. The oceans influence the worlds climate by storing solar energy and distributing it around the planet through currents and atmospheric winds.This publication is all about developing your students understandings of earths oceans and the major effect they have on climate. Understanding and interpreting local weather data and understanding the relationship between weather and climate are important first steps to understanding larger-scale global climate changes. Activities that ask students to collect and analyze local weather data as well as analyze global data can be found in the Lessons and Activities section. Analyzing and interpreting data is a major focus of this publication. Numerous data sets can be found in the Sources for Real Data section. The Background Information section and the article Tomorrows Forecast will help reinforce your own content knowledge.

Lightle, Kimberly

2006-10-01

185

Jetstream: An Online Weather School  

NSDL National Science Digital Library

Jetstream is an online weather school from the National Oceanic and Atmospheric Administration's (NOAA) National Weather Service. Materials featured here include a selection of modules on weather on the web, the atmosphere, global weather, synoptic meteorology and other topics. A certificate of completion for each module can be printed by students who successfully complete their work. A topic matrix provides access to the sections for each module, beginning with an introduction and ending with review questions. In addition, an appendix for teachers features a glossary, list of acronyms, downloading instructions, answers to review questions, and overviews of the lesson plans within each module.

2006-01-01

186

MSATT Workshop on Chemical Weathering on Mars  

NASA Technical Reports Server (NTRS)

The topics covered with respect to chemical weathering on Mars include the following: Mars soil, mineralogy, spectroscopic analysis, clays, silicates, oxidation, iron oxides, water, chemical reactions, geochemistry, minerals, Mars atmosphere, atmospheric chemistry, salts, planetary evolution, volcanology, Mars volcanoes, regolith, surface reactions, Mars soil analogs, carbonates, meteorites, and reactivity.

Burns, Roger (editor); Banin, Amos (editor)

1992-01-01

187

The role of nitrification in silicate hydrolysis in soils near Santa Cruz, CA  

NASA Astrophysics Data System (ADS)

In some ecosystems, nitrification (microbial conversion of ammonium to nitrate) may supplant carbonic acid as a source of acidity and drive silicate weathering. Recent studies have explored the impact that ammonium fertilizer addition to soils has on weathering of various mineral types (Pacheco et al. 2013) and demonstrated directly that ammonium addition to soils can increase carbonate weathering (Gandois et al. 2011). Some evidence points to a role for nitrification in silicate weathering at a series of coastal grassland terraces near Santa Cruz, CA. Weathering rates in these soils have been estimated using the byproducts of silicate hydrolysis (Cl--adjusted Na+ and other cations). If carbonic acid from dissolved CO2 is the source of acidity in silicate hydrolysis, bicarbonate should balance the cations produced during weathering. However, in the Santa Cruz soils nitrate is the dominant anion balancing cation concentrations. High concentrations of CO2 (>1%) at depths greater than 1m may provide additional support for nitrification-based silicate hydrolysis at Santa Cruz. We evaluate the role of nitrification in silicate weathering for soils from the Santa Cruz Marine Terrace Chronosequence using a column ammonium-addition experiment and a basic weathering model. The column experiment uses ammonium inputs in excess of natural inputs and measures weathering products in eluted fluids over time. The model incorporates more realistic estimates of ammonium input and explores whether the observed concentrations of cations, nitrate and CO2 seen at Santa Cruz can be explained by nitrification-driven acidity or if other inputs need to be considered. Gandois, L, Perrin, A-S, and Probst, A. 2011. Impact of nitrogenous fertiliser-induced proton release on cultivated soils with contrasting carbonate contents: A column experiment. Geochimica et Cosmochimica Acta 75 pp. 1185-1198. Pacheco, F, Landim, P, and Szocs, T. 2013. Anthropogenic impacts on mineral weathering: A statistical perspective. Applied Geochemistry 36 pp. 34-48.

Kyker-Snowman, E.; White, A.; Lawrence, C. R.; Schulz, M. S.

2013-12-01

188

Weather Forecasting  

NSDL National Science Digital Library

Weather Forecasting is a set of computer-based learning modules that teach students about meteorology from the point of view of learning how to forecast the weather. The modules were designed as the primary teaching resource for a seminar course on weather forecasting at the introductory college level (originally METR 151, later ATMO 151) and can also be used in the laboratory component of an introductory atmospheric science course. The modules assume no prior meteorological knowledge. In addition to text and graphics, the modules include interactive questions and answers designed to reinforce student learning. The module topics are: 1. How to Access Weather Data, 2. How to Read Hourly Weather Observations, 3. The National Collegiate Weather Forecasting Contest, 4. Radiation and the Diurnal Heating Cycle, 5. Factors Affecting Temperature: Clouds and Moisture, 6. Factors Affecting Temperature: Wind and Mixing, 7. Air Masses and Fronts, 8. Forces in the Atmosphere, 9. Air Pressure, Temperature, and Height, 10. Winds and Pressure, 11. The Forecasting Process, 12. Sounding Diagrams, 13. Upper Air Maps, 14. Satellite Imagery, 15. Radar Imagery, 16. Numerical Weather Prediction, 17. NWS Forecast Models, 18. Sources of Model Error, 19. Sea Breezes, Land Breezes, and Coastal Fronts, 20. Soundings, Clouds, and Convection, 21. Snow Forecasting.

Nielsen-Gammon, John

1996-09-01

189

Neutralization of atmospheric acidity by chemical weathering in an alpine drainage basin in the North Cascade Mountains  

Microsoft Academic Search

The most important weathering reaction that neutralizes incoming atmospheric acidity in the South Cascade Lake basin is weathering of calcite, which occurs in trace amounts in veins, on joint surfaces, and as a subglacial surficial deposit. Although the basin is underlain by igneous and high-grade metamorphic rocks, weathering of plagioclase is quantitatively negligible; the principal silicate weathering reaction is alteration

James I. Drever; Douglas R. Hurcomb

1986-01-01

190

Ensemble hydrological prediction-based real-time optimization of a multiobjective reservoir during flood season in a semiarid basin with global numerical weather predictions  

NASA Astrophysics Data System (ADS)

Future streamflow uncertainties hinder reservoir real-time operation, but the ensemble prediction technique is effective for reducing the uncertainties. This study aims to combine ensemble hydrological predictions with real-time multiobjective reservoir optimization during flood season. The ensemble prediction-based reservoir optimization system (EPROS) takes advantage of 8 day lead time global numerical weather predictions (NWPs) by the Japan Meteorological Agency (JMA). Thirty-member ensemble streamflows are generated through running the water and energy budget-based distributed hydrological model fed with 30-member perturbed quantitative precipitation forecasts (QPFs) and deterministic NWPs. The QPF perturbation amplitudes are calculated from the QPF intensity and location errors during previous 8 day periods. The reservoir objective function is established to minimize the maximum reservoir water level (reservoir and upstream safety), the downstream flood peak (downstream safety), and the difference between simulated reservoir end water level and target level (water use). The system is evaluated on the Fengman reservoir basin (semiarid), which often suffers from extreme floods in summer and serious droughts in spring. The results show the ensemble QPFs generated by EPROS are comparable to those for JMA by using probability-based measures. The streamflow forecast error is significantly reduced by employing the ensemble prediction approach. The system has demonstrated high efficiency in optimizing reservoir objectives for both normal and critical flood events. Fifty-member ensembles generate a wider streamflow and reservoir release range than 10-member ensembles, but the ensemble mean end water levels and releases are comparable. The system is easy to operate and thereby feasible for practical operations in various reservoir basins.

Wang, Fuxing; Wang, Lei; Zhou, Huicheng; Saavedra Valeriano, Oliver C.; Koike, Toshio; Li, Wenlong

2012-07-01

191

Planetary Weather  

NSDL National Science Digital Library

This lesson plan is part of the DiscoverySchool.com lesson plan library for grades 6-8. It focuses on the weather conditions on other planets. After learning more about weather patterns, students research the weather on a given planet and create a visual display of the conditions there. It includes objectives, materials, procedures, discussion questions, evaluation ideas, suggested readings, and vocabulary. There are videos available to order which complement this lesson, and links to teaching tools for making custom quizzes, worksheets, puzzles and lesson plans.

192

Studies in colloidal silicates  

Microsoft Academic Search

Summary  The electrical conductance of the mixture obtained by the progressive addition of a sodium silicate to a ferric chloride solution\\u000a first decreases then increases and finally there is again a drop till the soda content of the silicate equals the chloride\\u000a content of the ferric chloride solutions. This shows that the free hydrochloric acid already present in the ferric chloride

K. L. Yadava; S. Ghosh

1957-01-01

193

Serpentines and related silicates  

NASA Astrophysics Data System (ADS)

This document is part of Subvolume I5? `Phyllosilicates - Part ?' of Volume 27 `Magnetic properties of non-metallic inorganic compounds based on transition elements` of Landolt-Börnstein - Group III `Condensed Matter'. It presents silicates belonging to the serpentines and related silicates, discussing their crystal structure and lattice parameters, magnetic properties, neutron diffraction data, nuclear gamma resonance (NGR) , nuclear magnetic resonance (NMR) and electron paramagnetic resonance (EPR) data,electrical resistivity, thermal properties, Raman and infrared spectra and optical properties.

Burzo, E.

194

Weatherizing America  

ScienceCinema

As Recovery Act money arrives to expand home weatherization programs across the country, Zachary Stewart of Phoenix, Ariz., and others have found an exciting opportunity not only to start working again, but also to find a calling.

Stewart, Zachary; Bergeron, T.J.; Barth, Dale; Qualis, Xavier; Sewall, Travis; Fransen, Richard; Gill, Tony;

2013-05-29

195

Weather Watchers  

NSDL National Science Digital Library

In this month-long interdisciplinary project students collect weather data, determine the best visual representation for displaying it, and discuss the patterns and implications of their findings. This resource includes extension and assessment suggestions and guiding questions.

2014-01-01

196

Weatherizing America  

ScienceCinema

As Recovery Act money arrives to expand home weatherization programs across the country, Zachary Stewart of Phoenix, Ariz., and others have found an exciting opportunity not only to start working again, but also to find a calling.

197

Space Weather  

NASA Astrophysics Data System (ADS)

Following James Van Allen's discovery of Earth's radiation belts (1958), it was immediately recognized that the space environment would be hostile to the communications satellites that had been envision by Arthur Clark (1945) and John Pierce (1955). Van Allen's discovery set off a burst of "space weather" research and engineering that continues to today, paralleling "space weather" research that had, prior to 1958, been directed toward understanding environment effects on cable and early wireless communications, electric power distribution, and pipelines. Van Allen's discovery also meant that the flight of humans above the sensible atmosphere would be fraught with more peril than mere weightlessness. This Van Allen lecture will discuss the space weather considerations that arose from Van Allen's discovery as well as space weather effects that occur from numerous other physical processes in the complex sun-heliosphere-magnetosphere environmental system.

Lanzerotti, L. J.

2005-05-01

198

Weatherizing America  

SciTech Connect

As Recovery Act money arrives to expand home weatherization programs across the country, Zachary Stewart of Phoenix, Ariz., and others have found an exciting opportunity not only to start working again, but also to find a calling.

Stewart, Zachary; Bergeron, T.J.; Barth, Dale; Qualis, Xavier; Sewall, Travis; Fransen, Richard; Gill, Tony

2009-01-01

199

Weathering the Snowball  

NASA Astrophysics Data System (ADS)

The Snowball Earth hypothesis posits that glaciation was globally synchronous at low-latitudes and that deglaciation occurred as a result of the build-up of pCO2 to extreme levels, resulting in a super-greenhouse aftermath following the global glaciation. Here we integrate U-Pb and Re-Os geochronology, along with Sr, Os and C isotopic data from Mongolia and North America to construct a new age model for the duration of Neoproterozoic glaciations and new composite curves of weathering proxies. These data suggest that the Sturtian-Rapitan glaciation(s) lasted >50 Myrs, and that deglaciation was globally coincident and resulted in sharp rises to more radiogenic seawater Sr and Os isotopic values, consistent with intense weathering in a post-Snowball super-greenhouse. We then build off of these data and discuss implications for initiation mechanisms, the nature of the glaciations and geochemical cycling. Particularly, was the Sturtian-Rapitan glaciation initiated by an increase in global weatherability? And do the Sturtian-Rapitan glacial deposits record multiple glacial events, a Jormungand climate state, or one long Snowball Earth?

Macdonald, F. A.; Rooney, A.; Dudas, F. O.

2012-12-01

200

Large-Scale Weather  

NSDL National Science Digital Library

In the previous chapter, we dealt with how the properties of air and water affected small-scale weather such as the formation of clouds, the formation of fog, and how comfortable you feel at different times of the year. In this chapter, we're going to go global, talking about major interactions between the Sun and Earth, the resulting effects on large air masses, and how these major interactions help us figure out what the weather's going to be tomorrow. As discussed earlier in the book, when science concepts are applied to the real world, things don't always work out exactly as expected. However, it is possible to get an overall picture of what's happening in large-scale weather.

Robertson, William C.

2005-01-01

201

Weathering Experiment  

NSDL National Science Digital Library

After discussing weathering and erosion in class, students are asked to do a small amount of research on different types of chemical weathering, physical weathering, and erosion processes (mostly out of their textbook). Outside of class students then dirty at least four similar dishes with the same type, thickness and aerial extent of food, preferably baked on to ensure maximum stick. One dish is set aside as a control (no weathering or erosion will occur for that dish). For each of the remaining three dishes, students devise an experiment that mimics some sort of chemical weathering, physical weathering, or erosion process (freeze/thaw, sand abrasion, oxidation, etc.). Prior to the experiments, the thickness of food is measured. Experiments are timed, and at the end of the experiment each plate is turned over to determine how much which method removed the greatest aerial extent of food. Experimental results are compared to the control plate to determine the actual effectiveness. Erosion/weathering rates are determined by dividing the thickness of food removed by the experimental time. Students then calculate how long it would take to remove a pile of food the size of the Geology building (assume a 50 m radius sphere), and to remove an amount of food equivalent to the depth of the Grand Canyon. Students then compare these results to rock erosion and weathering rates, performing similar calculations using these "real" rates (see the full project description for details). Photos of each step and the scientists are encouraged in their 2-3 page writeup.

Stelling, Pete

202

Weather Creator  

NSDL National Science Digital Library

This project explores factors that help create severe winter weather. An interactive simulation provides hands-on experience, followed by guiding questions and resource exploration. Form groups of three. Explore the following simulation: Weather Maker Simulator Use the simulation to answer the following questions on paper. 1. In general, when are winds formed? 2. When winds are blowing, how can you get them to stop? 3. What can you do to make it rain or even snow? 4. Does it always snow when ...

Kshumway

2009-09-28

203

Weather Maps  

NSDL National Science Digital Library

This lesson plan is part of the DiscoverySchool.com lesson plan library for grades K-5. It focuses on basic information about the weather and how different weather maps depict conditions. Included are objectives, materials, procedures, discussion questions, evaluation ideas, suggested readings, and vocabulary. There are videos available to order which complement this lesson, and links to teaching tools for making custom quizzes, worksheets, puzzles and lesson plans.

204

Some topics on geochemistry of weathering: a review.  

PubMed

Weathering is a complex process comprising physical disaggregation, chemical and biological decomposition of rocks and minerals transforming complex structure minerals in simpler ones. Hydrolysis of silicates is perhaps the most important process but associated certainly to biological weathering. It is discussed the role ofwaters: activities/concentrations of chemical species, pH, Eh, importance of complexes. Weathering is not only a destructive process. It can concentrate chemical species and form mineral deposits (kaolin, bauxite, Fe, Mn, P, Nb, Au). Weathering studies are important in pedology, engineering geology, hydrogeology, paleoclimatology and ecology. The use of stonemeal is based upon the study of rock weathering. PMID:17143414

Formoso, Milton L L

2006-12-01

205

Mountain weather and climate  

SciTech Connect

Mountain environments are reaching the world environmental agenda of concern. The first edition of this book provided a well organized set of principles on how weather and climate processes operate in mountain environments; it was and remains the major reference on the subject. This second edition remains in the original format but adds new material, including updates and increased bibliography and stressing the importance of the temporal dimension of mountain climates and the potential sensitivity of these environments to global change processes.

Barry, R.G.

1992-01-01

206

Space Weather  

NASA Astrophysics Data System (ADS)

This volume provides a comprehensive overview of our current observational knowledge, theoretical understanding, and numerical capability with regard to the phenomena known as space weather. Space weather refers to conditions on the Sun and in the solar wind, magnetosphere, ionosphere, and thermosphere that can influence the performance and reliability of space-borne and ground-based technological systems, and can endanger human life or health. The rapid advance in these technologies has provided us with unprecedented capability and convenience, and we have come to rely on them more and more. Technology has reduced society's risk to many kinds of natural disasters, but through its own vulnerability, it has actually increased society's risk to space weather. Adverse conditions in the space environment can cause disruption of satellite operations, communications, navigation, and electric power distribution grids, leading to a variety of socioeconomic losses.

Song, Paul; Singer, Howard J.; Siscoe, George L.

207

Chemical Weathering in the Amur River  

NASA Astrophysics Data System (ADS)

The Amur River is the fourth largest river (~1,855,000 km2) in north Eurasia which flow into the Pacific Ocean. It flows through 4 countries-the Russian Far East, northeast China, east Mongolia and a small territory of North Korea. Climatic and ecological conditions differ significantly from western intercontinental region to eastern coastal area. Southern part of the Amur basin is mostly lowland region with alluvial deposits and various rocks of sedimentary and magmatic origin. In the northern part, there are mountains with siliceous and carbonaceous sedimentary rocks, and permafrost plays an important role in river chemical discharge. We examined dissolved major element and Sr isotopic compositions of 19 summer samples in the middle reach of the Amur to better understand the relationship between chemical weathering, geology, and climate (with the aid of GlS). We found that the 87Sr/86Sr ratios fall a narrow the range of 0.709-0.712 and the TDS (total dissolved solids) is about 80 (40-180) mg/L. Kaolinite is the thermodynamically stable silicate mineral for most samples. We quantified chemical weathering rates using an inverse model: rain accounts for (2-14)% of the total cationic concentration, evaporites (3-19)%, carbonates (43-77)%, and silicates (14-32)%. Net CO2 consumption rate by silicate weathering in the Amur basin is in the range of (10-100) ×103 mol/km2/yr, and the value at the main channel above confluence with the Sungari tributary is ~10 ×103 mol/km2/yr. We tested correlations between the CO2 consumption rates by silicate weathering and various climatic (air temperature, precipitation, and runoff) and geologic (relief, slope, elevation) factors calculated using GIS. Stepwise regression using SPSS on the entire data set yielded best correlation (negative) with elevation (R2 = 0.6823, p = 0.0002).

Moon, S.; Huh, Y.

2006-12-01

208

Wild Weather  

NSDL National Science Digital Library

In this online, interactive module, students learn about severe weather (thunderstorms, hurricanes, tornadoes, and blizzards) and the key features for each type of "wild weather" using satellite images. The module is part of an online course for grades 7-12 in satellite meteorology, which includes 10 interactive modules. The site also includes lesson plans developed by teachers and links to related resources. Each module is designed to serve as a stand-alone lesson, however, a sequential approach is recommended. Designed to challenge students through the end of 12th grade, middle school teachers and students may choose to skim or skip a few sections.

209

Weather Forecasting  

NSDL National Science Digital Library

Weather Forecasting is one of several online guides produced by the Weather World 2010 project at the University of Illinois. These guides use multimedia technology and the dynamic capabilities of the web to incorporate text, colorful diagrams, animations, computer simulations, audio, and video to introduce topics and concepts in the atmospheric sciences. This module introduces forecast methods and the numerous factors one must consider when attempting to make an accurate forecast. Sections include forecasting methods for different scenarios, surface features affecting forecasting, forecasting temperatures for day and night, and factors for forecasting precipitation.

2010-01-01

210

Space Weather  

NSDL National Science Digital Library

With three levels to choose from on each page - beginner, intermediate or advanced - this site provides information on Space Weather and the terms scientists use to describe the everchanging conditions in space. Explosions on the Sun create storms of radiation, fluctuating magnetic fields, and swarms of energetic particles. These phenomena travel outward through the Solar System with the solar wind. Upon arrival at Earth, they interact in complex ways with Earth's magnetic field, creating Earth's radiation belts and the Aurora. Some space weather storms can damage satellites, disable electric power grids, and disrupt cell phone communications systems. This site provides images, activities, and interesting facts about all of these events.

2004-02-06

211

Weather Activity  

NSDL National Science Digital Library

This project explores factors that help create severe winter weather. An interactive simulation provides hands-on experience, followed by guiding questions and resource exploration. Form groups of three. Explore the following simulation: Weather Maker Simulator Use the simulation to answer the following questions on paper. 1. Why does the wind blow? 2. When winds are blowing, how can you get them to stop? 3. What happens when the temperature is the same? 4. What happens when there is high relative humidity? 5. What ...

missy.jones@gmail.com

2009-09-28

212

Smooth Sailing for Weather Forecasting  

NASA Technical Reports Server (NTRS)

Through a cooperative venture with NASA's Stennis Space Center, WorldWinds, Inc., developed a unique weather and wave vector map using space-based radar satellite information and traditional weather observations. Called WorldWinds, the product provides accurate, near real-time, high-resolution weather forecasts. It was developed for commercial and scientific users. In addition to weather forecasting, the product's applications include maritime and terrestrial transportation, aviation operations, precision farming, offshore oil and gas operations, and coastal hazard response support. Target commercial markets include the operational maritime and aviation communities, oil and gas providers, and recreational yachting interests. Science applications include global long-term prediction and climate change, land-cover and land-use change, and natural hazard issues. Commercial airlines have expressed interest in the product, as it can provide forecasts over remote areas. WorldWinds, Inc., is currently providing its product to commercial weather outlets.

2002-01-01

213

Putting Weather into Weather Derivatives  

NASA Astrophysics Data System (ADS)

Just as weather forecasting has a colorful and often farsighted history within geophysics, financial mathematics has a long and turbulent history within mathematics. Thus it is no surprise that the intersection of real physics and real financial mathematics provides a rich source of problems and insight in both fields. This presentation targets open questions in one such intersection: quantifying ``weather risk.'' There is no accepted (operational) method for including deterministic information from simulation models (numerical weather forecasts, either best guess or by ensemble forecasting methods), into the stochastic framework most common within financial mathematics. Nor is there a stochastic method for constructing weather surrogates which has been proven successful in application. Inasmuch as the duration of employable observations is short, methods of melding short term, medium-range and long term forecasts are needed. On these time scales, model error is a substantial problem, while many methods of traditional statistical practice are simply inappropriate given our physical understanding of the system. A number of specific open questions, along with a smaller number of potential solutions, will be presented. >http://www.maths.ox.ac.uk/~lenny/WeatherRisk

Smith, L. A.; Smith, L. A.

2001-12-01

214

21 CFR 573.260 - Calcium silicate.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 false Calcium silicate. 573.260 Section 573.260 Food and Drugs... Food Additive Listing § 573.260 Calcium silicate. Calcium silicate, including synthetic calcium silicate,...

2013-04-01

215

21 CFR 573.260 - Calcium silicate.  

Code of Federal Regulations, 2010 CFR

...2009-04-01 2009-04-01 false Calcium silicate. 573.260 Section 573.260 Food and Drugs... Food Additive Listing § 573.260 Calcium silicate. Calcium silicate, including synthetic calcium silicate,...

2009-04-01

216

21 CFR 172.410 - Calcium silicate.  

Code of Federal Regulations, 2010 CFR

...2009-04-01 2009-04-01 false Calcium silicate. 172.410 Section 172.410 Food and Drugs...CONSUMPTION Anticaking Agents § 172.410 Calcium silicate. Calcium silicate, including synthetic calcium silicate,...

2009-04-01

217

21 CFR 573.260 - Calcium silicate.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Calcium silicate. 573.260 Section 573.260 Food and Drugs... Food Additive Listing § 573.260 Calcium silicate. Calcium silicate, including synthetic calcium silicate,...

2010-04-01

218

Weather Stations  

NSDL National Science Digital Library

This is a series of seven brief activities about Jupiter's atmosphere and weather. Learners will look at Jupiter's distinct banded appearance, violent storms, and clouds of many different colors. The activities are part of Explore! Jupiter's Family Secrets, a series designed to engage children in space and planetary science in libraries and informal learning environments.

219

Wonderful Weather  

NSDL National Science Digital Library

In this activity, learners conduct three experiments to examine temperature, the different stages of the water cycle, and how convection creates wind. These activities can be used individually or as a group for a lesson on weather. Note: boiling water is required for this activity; adult supervision required.

Workshop, Mission S.

2013-01-01

220

Today's Weather  

NSDL National Science Digital Library

This activity is part of Planet Diary and contains an online exploration of weather maps. Students use current maps to learn about and locate different features such as low-pressure areas and fronts. They then explore how these are related to severe storms.

221

Weather Wordsearch  

NSDL National Science Digital Library

Find the 12 weather related words in this word search brought to you by the Southeast Regional Climate Center (SERCC). When you finish finding all 12 words, hit the restart button to re-scramble the letters and start all over again!

2007-01-01

222

The Weather Doctor  

NSDL National Science Digital Library

Published by Spectrum Educational Enterprises, The Weather Doctor Web site is maintained by meteorologist Keith Heidorn. Visitors to the site will find everything from the joys of weather watching, to making rain, to weather history, to much more. Coming from someone who clearly enjoys what they do, this site explores unique aspects of weather including weather people, weather history, and weather and arts.

Heidorn, Keith.

2002-01-01

223

The role of basalt weathering on climate: the Siberian traps  

NASA Astrophysics Data System (ADS)

The Siberian traps represent one of the most important flood basalt provinces on Earth. Their onset coincides with a profound faunal mass extinction at the Permo-Trias boundary (250 my ago). The volcanic eruption has also environmental and climatic effects through aerosols and gases injection into the atmosphere. Chemical weathering processes play a major role in biogeochemical cycles and climate evolution. In particular, the weathering of silicate rocks represents an important sink of atmospheric CO_2. At the million-year timescale, the volcanic release of CO_2 into the atmosphere-ocean system is balanced by its consumption during silicate weathering followed by carbonate deposition on the seafloor. Recent data have shown that chemical weathering of basalt is five to ten times more efficient than weathering of acidic silicate rocks such as granite or gneiss (Dessert et al., EPSL, 188 : 459-474, 2001). Thus the weathering of basaltic rocks consumes more atmospheric CO_2 than other silicate rocks. In the case of subaerial basaltic volcanism, an eruption not only releases CO_2 to the atmosphere, but also produces basaltic rocks which weather rapidly, enhancing CO_2 consumption rates. Currently, the Siberian basaltic traps are located in a cold and dry region. The weathering rates of this province are low, and the climatic impact is thus currently low. But in the past, the latitudinal temperature gradient was smaller. During the Permian, the climate was significantly warmer than today. Thus the chemical weathering of the Siberian traps was enhanced at that time, and this process led to a long-term impact on the Triassic climate and on the carbon cycle. The used model calculates the traps impact on the long-term carbon cycle and climate evolution. This model has been refined and adapted to high latitudes environments. We quantify the cooling caused by traps weathering.

Grard, A.; François, L.; Dessert, C.; Dupré, B.; Goddéris, Y.

2003-04-01

224

Weathering and the mobility of phosphorus in the catchments and forefields of the Rhône and Oberaar glaciers, central Switzerland: Implications for the global phosphorus cycle on glacial-interglacial timescales  

NASA Astrophysics Data System (ADS)

In this study we evaluate the dynamics of the biophile element phosphorus (P) in the catchment and proglacial areas of the Rhône and Oberaar glaciers (central Switzerland). We analysed erosion and dissolution rates of P-containing minerals in the subglacial environment by sampling water and suspended sediment in glacier outlets during three ablation and two accumulation seasons. We also quantified biogeochemical weathering rates of detrital P in proglacial sedimentary deposits using two chronosequences of samples of fresh, suspended, material obtained from the Oberaar and Rhône water outlets, Little-Ice-Age (LIA) moraines and Younger Dryas (YD) tills in each catchment. Subglacial P weathering is mainly a physical process and detrital P represents more than 99% of the precipitation-corrected total P denudation flux (234 and 540 kg km -2 yr -1 for the Rhône and Oberaar catchments, respectively). The calculated detrital P flux rates are three to almost five times higher than the world average flux. The precipitation-corrected soluble reactive P (SRP) flux corresponds to 1.88-1.99 kg km -2 yr -1 (Rhône) and 2.12-2.44 kg km -2 yr -1 (Oberaar), respectively. These fluxes are comparable to those of tropical rivers draining transport-limited, tectonically inactive weathering areas. In order to evaluate the efficiency of detrital P weathering in the Rhône and Oberaar proglacial areas, we systematically graded apatite grains extracted from the chronosequence in each catchment relative to weathering-induced changes in their surface morphologies (grades 1-4). Fresh apatite grains are heavily indented and dissolution rounded (grade 1). LIA grains from two 0-10 cm deep moraine samples show extensive dissolution etching, similar to surface grains from the YD profile (mean grades 2.7, 3.5 and 3.5, respectively). In these proglacial deposits, the weathering front deepens progressively as a function of time due to biocorrosion in the evolving acidic pedosphere , with mechanical indentations on grains acting as sites of preferential dissolution. We also measured iron-bound, organic and detrital P concentrations in the chronosequence and show that organic and iron-bound P has almost completely replaced detrital P in the top layers of the YD profiles. Detrital P weathering rates are calculated as 310 and 280 kg km -2 yr -1 for LIA moraines and 10 kg km -2 yr -1 for YD tills. During the first 300 years of glacial sediment exposure P dissolution rates are shown to be approximately 70 times higher than the mean global dissolved P flux from ice-free continents. After 11.6 kyr the flux is 2.5 times the global mean. These data strengthen the argument for substantial changes in the global dissolved P flux on glacial-interglacial timescales. A crude extrapolation from the data described here suggests that the global dissolved P flux may increase by 40-45% during the first few hundred years of a deglaciation phase.

Föllmi, Karl B.; Hosein, Rachel; Arn, Kaspar; Steinmann, Philipp

2009-04-01

225

Instruments and Methods Monitoring ice-capped active Volc´ an Villarrica, southern Chile, using terrestrial photography combined with automatic weather stations and global positioning systems  

Microsoft Academic Search

Volcan Villarrica (39 ? 25? 12?? S, 71 ? 56? 27?? W; 2847 m a.s.l.) is an active ice-capped volcano located in the Chilean lake district. The surface energy balance and glacier frontal variations have been monitored for several years, using automatic weather stations and satellite imagery. In recent field campaigns, surface topography was measured using Javad GPS receivers. Daily

Javier G. CORRIPIO; Ben BROCK; Jorge CLAVERO; Jens WENDT

226

Insolation data manual: Long-term monthly averages of solar radiation, temperature, degree-days and global KT for 248 National Weather Service stations  

Microsoft Academic Search

Monthly averaged data is presented which describes the availability of solar radiation at 248 National Weather Service stations. Monthly and annual average daily insolation and temperature values have been computed from a base of 24 to 25 years of data. Average daily maximum, minimum, and monthly temperatures are provided for most locations in both Celsius and Fahrenheit. Heating and cooling

C. L. Knapp; T. L. Stoffel; S. D. Whitaker

1980-01-01

227

Insolation data manual: long-term monthly averages of solar radiation, temperature, degree-days and global anti K\\/sub T\\/ for 248 national weather service stations  

Microsoft Academic Search

Monthly averaged data is presented which describes the availability of solar radiation at 248 National Weather Service stations. Monthly and annual average daily insolation and temperature values have been computed from a base of 24 to 25 years of data. Average daily maximum, minimum, and monthly temperatures are provided for most locations in both Celsius and Fahrenheit. Heating and cooling

C. L. Knapp; T. L. Stoffel; S. D. Whitaker

1980-01-01

228

GLOBAL CHANGE RESEARCH NEWS #33: PUBLICATION OF RESEARCH AGENDA FROM UNITED STATES - CANADA SYMPOSIUM ON NORTH AMERICAN CLIMATE CHANGE AND WEATHER EXTREMES  

EPA Science Inventory

A three-day workshop on climate variability and change and extreme weather events in North America was held in October 1999 in Atlanta, Georgia. The workshop was a bi-national effort conducted under the auspices of a United States - Canada agreement fostering cooperation on activ...

229

NOAA Weather Radio Hourly Weather Roundup Formatter.  

National Technical Information Service (NTIS)

The National Weather Service (NWS) is planning to replace the aging National Oceanic and Atmospheric Administration (NOAA) Weather Radio (NWR) as part of its modernization program. The Office of Meteorology (OM) selected the Hourly Weather Roundup (HWR) t...

G. F. Battel G. A. Kokolis J. E. Calkins

1994-01-01

230

Weather Watchers  

NSDL National Science Digital Library

Students are introduced to some essential meteorology concepts so they more fully understand the impact of meteorological activity on air pollution control and prevention. First, they develop an understanding of the magnitude and importance of air pressure. Next, they build a simple aneroid barometer to understand how air pressure information is related to weather prediction. Then, students explore the concept of relative humidity and its connection to weather prediction. Finally, students learn about air convection currents and temperature inversions. In an associated literacy activity, students learn how scientific terms are formed using Latin and Greek roots, prefixes and suffixes, and are introduced to the role played by metaphor in language development. Note: Some of these activities can be conducted simultaneously with the air quality activity (What Color Is Your Air Today?) of Air Pollution unit, Lesson 1.

Integrated Teaching And Learning Program

231

Weather Cycles  

NSDL National Science Digital Library

We are professionals in the teaching profession. We designed this project for children ranging from 4th grade to 6th grade. This project explores factors that help create severe winter weather. An interactive simulation provides hands-on experience, followed by guiding questions and resource exploration. YOU WILL NEED: Paper with copied questions, Overhead projector and Students broken up into groups of 3. Form groups of three. Have each group explore the following simulation: Weather Maker Simulator Have students use the simulation to answer the following questions on paper. They should be discussing the questions in their groups. 1. In general, when are winds formed? 2. When winds are blowing, how can you get them to stop? 3. What ...

Mitchell, Mrs.

2010-09-23

232

Weathering Corruption  

Microsoft Academic Search

Could bad weather be responsible for U.S. corruption? Natural disasters create resource windfalls in the states they strike by triggering federally provided natural-disaster relief. By increasing the benefit of fraudulent appropriation and creating new opportunities for such theft, disaster-relief windfalls may also increase corruption. We investigate this hypothesis by exploring the effect of disaster relief provided by the Federal Emergency

2008-01-01

233

Does mineral surface area affect chemical weathering rates?  

NASA Astrophysics Data System (ADS)

Iceland is a basaltic volcanic island representative of the high relief, volcanic and tectonic active islands that contribute over 45% of river suspended material to the oceans worldwide (Milliman and Syvitski, 1992). These islands have enormous mechanical and chemical weathering rates due to the combined effects of high relief, high runoff, the presence of glaciers and easily weathered volcanic rocks, and a lack of sedimentary traps. In total, Iceland delivers 0.7% of the worldwide river suspended matter flux to the ocean, which is approximately one fourth that of Africa (Tómasson, 1990). River suspended matter from volcanic islands is highly reactive in seawater and might play an important role in the global carbon cycle (Gislason et al., 2006). Thus it is important to define and understand the mechanical and chemical weathering rates of these islands. Experimental dissolution experiments performed in the laboratory suggest that chemical weathering rates should be proportional to rock-water interfacial surface area. This hypothesis is tested in the present study through a study of the chemical composition of suspended material collected from rivers located in Northeast Iceland. These rivers were selected for this study because their catchments essentially monolithic, consisting of uniform compositioned and aged basalts. Gaillardet (1999) described weathering intensities of the worlds river systems to be from 1 (low weathering intensity) to 25 (high weathering intensity). These indexes were calculated to be from 1.8 to 3.2 in rivers in NE-Iceland (Eiriksdottir et al., 2008). The surface area of sediments is inversely proportional to particle size; smaller particles have larger specific surface areas. As a result, smaller particles should weather faster. This trend is confirmed by the measured compositions of analyzed suspended material. The concentration of insoluble elements (Zr, Fe, Cu, Ni, Y) is found to increase in the suspended material, whereas the concentration of soluble elements (Na, Ca, Ba, V) decrease with decreasing particle size in samples collected from various catchments. References. Eiriksdottir E.S., Louvat P., Gislason S.R., Óskarsson N., Hardardóttir J., 2008. Temporal variation of chemical and mechanical weathering in NE Iceland: Evaluation of a steady-state model of erosion. EPSL 272, 78-88 Gaillardet, J., Dupré, B., Allegre, C.J., Négrel, P., 1999b. Geochemistry of large river suspended sediments: silicate weathering or recycling tracer? Geochim. Cosmochim. Acta 63, 4037-4051. Gislason, S.R., Oelkers, E.H., Snorrason, Á., 2006. Role of river-suspended material in the global carbon cycle. Geology 34, 49-52. Milliman, J.D., Syvitski, J.P.M., 1992. Geomorphic/tectonic control of sediment discharge to the ocean: the importance of small mountainous rivers. J. Geol. 100, 525-544. Tómasson, H., 1990. Suspended material in Icelandic rivers. In: Guttormur, S. (Ed.), Vatnid og Landid. Orkustofnun, Reykjavik, pp. 169-174.

Salome Eiriksdottir, Eydis; Reynir Gislason, Sigurdur; Oelkers, Eric H.

2010-05-01

234

Index of Air Weather Service Technical Publications. Headquarters AWS and Subordinate Units.  

National Technical Information Service (NTIS)

This index lists technical publications of the US Air Force Air Weather Service including its subordinate units. These units include the Air Force Global Weather Central, US Air Force Environmental Technical Applications Center, 1st Weather Wing, 2nd Weat...

1982-01-01

235

Weathering of sulfides on Mars  

NASA Technical Reports Server (NTRS)

Pyrrhotite-pentlandite assemblages in mafic and ultramafic igneous rocks may have contributed significantly to the chemical weathering reactions that produce degradation products in the Martian regolith. By analogy and terrestrial processes, a model is proposed whereby supergene alteration of these primary Fe-Ni sulfides on Mars has generated secondary sulfides (e.g., pyrite) below the water table and produced acidic groundwater containing high concentrations of dissolved Fe, Ni, and sulfate ions. The low pH solutions also initiated weathering reactions of igneous feldspars and ferromagnesian silicates to form clay silicate and ferric oxyhydroxide phases. Near-surface oxidation and hydrolysis of ferric sulfato-and hydroxo-complex ions and sols formed gossan above the water table consisting of poorly crystalline hydrated ferric sulfates (e.g., jarosite), oxides (ferrihydrite, goethite), and silica (opal). Underlying groundwater, now permafrost contains hydroxo sulfato complexes of Fe, Al, Mg, Ni, which may be stabilized in frozen acidic solutions beneath the surface of Mars. Sublimation of permafrost may replenish colloidal ferric oxides, sulfates, and phyllosilicates during dust storms on Mars.

Burns, Roger G.; Fisher, Duncan S.

1987-01-01

236

Seafloor weathering buffering climate: numerical experiments  

NASA Astrophysics Data System (ADS)

Continental silicate weathering is widely held to consume atmospheric CO2 at a rate controlled in part by temperature, resulting in a climate-weathering feedback [Walker et al., 1981]. It has been suggested that weathering of oceanic crust of warm mid-ocean ridge flanks also has a CO2 uptake rate that is controlled by climate [Sleep and Zahnle, 2001; Brady and Gislason, 1997]. Although this effect might not be significant on present-day Earth [Caldeira, 1995], seafloor weathering may be more pronounced during snowball states [Le Hir et al., 2008], during the Archean when seafloor spreading rates were faster [Sleep and Zahnle, 2001], and on waterworld planets [Abbot et al., 2012]. Previous studies of seafloor weathering have made significant contributions using qualitative, generally one-box, models, and the logical next step is to extend this work using a spatially resolved model. For example, experiments demonstrate that seafloor weathering reactions are temperature dependent, but it is not clear whether the deep ocean temperature affects the temperature at which the reactions occur, or if instead this temperature is set only by geothermal processes. Our goal is to develop a 2-D numerical model that can simulate hydrothermal circulation and resulting alteration of oceanic basalts, and can therefore address such questions. A model of diffusive and convective heat transfer in fluid-saturated porous media simulates hydrothermal circulation through porous oceanic basalt. Unsteady natural convection is solved for using a Darcy model of porous media flow that has been extensively benchmarked. Background hydrothermal circulation is coupled to mineral reaction kinetics of basaltic alteration and hydrothermal mineral precipitation. In order to quantify seafloor weathering as a climate-weathering feedback process, this model focuses on hydrothermal reactions that influence carbon uptake as well as ocean alkalinity: silicate rock dissolution, calcium and magnesium leaching reactions, carbonate precipitation, and clay formation.

Farahat, N. X.; Archer, D. E.; Abbot, D. S.

2013-12-01

237

The extent of disorder and properties of silicate glasses, melts and layer-silicates: Spectroscopic analysis and quantum chemical calculations  

NASA Astrophysics Data System (ADS)

Silicate glasses and melts have long been studied not only because of their geologic relevance to natural magmas but also because of their technological applications to the glass industry. The inherent aspect of silicate glasses and melts are extent of disorder among framework units and the distribution of internal structural variables. This dissertation is for a systematic exploration of the extent of disorder in silicate glasses, melts and layer-silicates using NMR spectroscopy and analysis both by theoretical prediction based on statistical thermodynamics and by quantum chemical calculations. The objective of the dissertation includes exploration of the consequences of the degree of disorder of the system on physical properties of interest to geologists and material scientists. The degree of randomness in framework in silicate glasses including borosilicate and aluminosilicates was quantified using the models introducing order parameters such as the degree of Al avoidance and the degree of inter-mixing. The model in conjunction with input from high-resolution NMR and quantum chemical calculations was used to calculate the configurational thermodynamic properties in these glasses. We presented general framework for understanding the extent of short-range order in framework silicates, demonstrating that a more complete description of the macroscopic thermodynamic properties of silicates can be derived from information on the degree of framework disorder and provides another strong link between structures of melts and properties. Bond angle and length distributions, one aspect of topological disorder in this system, were also quantified using these methods. 17O MQ (multiple quantum) MAS NMR at high fields were applied to better understand reactivity of oxygen sites in layer silicates which are one of the most dominant constituents of the Earth's surfaces. Several basal and apical oxygen sites in model clay minerals were resolved, providing improved prospects for atomic scale understanding on the geochemical processes such as weathering.

Lee, Sung Keun

238

Weather Science Hotlist  

NSDL National Science Digital Library

The Franklin Institute Online offers the metadata Web site Weather Science Hotlist. The page contains dozens of links organized into ten topics that include Online Exhibits, Weather Right Now, Background Information, Severe Weather, El Nino/ La Nina, Historical Weather, Career Connections, Activities, Atmosphere, and Weather Forecasting. A great source for anyone looking for online weather information.

2008-04-11

239

Can enhanced weathering remove carbon dioxide from the atmosphere to prevent climate change? (Invited)  

NASA Astrophysics Data System (ADS)

On long timescales, silicate weathering provides the ultimate sink for CO2 released by volcanic degassing and, because the rate of such weathering is temperature dependant, this sink is thought to respond to climate change to provide a strong negative feedback stabilising Earth's climate. An increase of global weathering rates is expected in response to anthropogenic warming and this increased weathering will ultimately (on the timescale of hundreds of thousands of years) serve to remove additional CO2 and return the climate system to lower temperatures. Some have proposed that accelerating this natural process by adding ground minerals to the land surface may help to prevent climate change. However, a major challenge in assessing such a proposal is the lack of experimental kinetic data for minerals added to the environment. Here we will present results from an experiment in which a forsterite rich olivine (Mg2SiO4) was added to the top of a soil column extracted from an agricultural field. A solution was passed through the columns over a period of 5 months and the drainage waters were collected and analysed. The greater flux of Mg measured eluting from the treated soil can be used to constrain the weathering rate of the olivine. A weathering rate can be determined by normalising the rate of magnesium flux to the surface area of olivine in the soil. By combining this information with a simple shrinking core model, we can estimate that an average particle size less than 1 ?m would be required in order for the olivine to completely dissolve in a year. Therefore, the energy requirements for enhanced weathering are large >2 GJ(electrical) per net tonne of CO2 sequestered, but it is at least comparable to direct air capture technologies. These preliminary results suggest limited carbon capture potential for enhanced weathering in temperate agricultural soils. However, some environments may be better suited (e.g. humid tropical agricultural soils) and additional experimental work is required to test these. This initial assessment does not include the plethora of other impacts that may be caused by enhanced weathering (ocean fertilisation, dust generation, soil carbon changes, K-feldspar fertilisation). More generally, terrestrial enhanced weathering is only one of a number of technologies that propose to add alkalinity to the surface ocean. The findings from this study will be presented in the context of this broader research field of ocean alkalinity modification.

Renforth, P.; Pogge von Strandmann, P.; Henderson, G. M.

2013-12-01

240

Weather Tamers  

NSDL National Science Digital Library

Problem-based learning experiences that extend at least two weeks provide an opportunity for students to investigate a real-world problem while learning science content and skills in an exciting way. Meteorology provides a wealth of problems students can investigate while learning specific science concepts and skills found frequently in middle level national and state curricula standards. The hands-on activity described in this article helps students learn about the science behind weather events by planning, constructing, and testing models of cities exposed to a series of simulated hurricanes and tornado conditions.

Sterling, Donna R.; Frazier, Wendy M.

2007-03-01

241

Mountain Weather  

NSDL National Science Digital Library

Mountains can be awe-inspiring both for the vistas they provide and for the weather events and long-term climate systems they support. This interactive feature illustrates how a moisture-laden air mass interacts with a mountain slope to produce characteristic patterns of precipitation over the mountain and surrounding areas. Viewers can see how clouds and precipitation form as the air mass ascends the windward side of the peak, and observe the rain shadow created on the leeward side by the descending, warmed, and moisture-depleted air. A background essay and list of discussion questions supplement the interactive feature.

242

Weather Photography  

NSDL National Science Digital Library

Ph.D. student Harald Edens describes himself as a "photographer of lightning, clouds, atmospheric optical phenomena and astronomy". His Web site entitled Weather Photography proves this by providing a stunning collection of photographs and movies of atmospheric optics, lightning, clouds, and astronomy. The author describes how the photographs were taken, what equipment was used, and even discusses many of the phenomenon being observed such as mirages and halos. An added bonus of this very interesting site is that the author generously allows free personal use of the photographs.

2000-01-01

243

Weather Activities  

NSDL National Science Digital Library

This entertaining, interactive website is the perfect tool to educate users about the basics of weather forecasting and reporting. The two educational modules, created by EdHeads, each contain three levels and are designed for grades four through nine. While discovering how to predict a three-day forecast, students learn about warm and cold fronts, wind direction and speed, high and low pressure systems, isobars, and humidity. Teachers can find a helpful guide discussing how best to use the site as well as providing an overview of science standards, lesson plans, and pre- and post-tests for students.

244

Destructive Weather  

NSDL National Science Digital Library

What are the effects of different types of destructive weather? Learn All About Hurricanes Record on your chart 3 things that you learned. Watch a Hurricane Video These are the devastating Effects of Hurricanes Learn All About Tornadoes Record on your chart 3 things that you learned. Watch a Tornado Video These are the devastating Effects of tornadoes Learn All About Thunderstorms Record on your chart 3 things that you learned. These are the devastating Effects of thunderstorms Follow these important tips To keep safe. ...

Alizabethirwin

2010-11-03

245

Chemical Weathering, Atmospheric CO 2 , and Climate  

Microsoft Academic Search

There has been considerable controversy concerning the role of chem- ical weathering in the regulation of the atmospheric partial pressure of carbon dioxide, and thus the strength of the greenhouse effect and global climate. Arguments center on the sensitivity of chemical weathering to climatic factors, especially temperature. Laboratory studies reveal a strong dependence of mineral dissolution on temperature, but the

Lee R. Kump; Susan L. Brantley; Michael A. Arthur

2000-01-01

246

Interannual variability of Martian weather  

Microsoft Academic Search

Pressure, temperature, imaging, and wind data from the Mutch Memorial Station, the Viking lander located in Mars' subtropics, are used to demonstrate the existence of two disctinct regimes of northern hemisphere winter weather on Mars. One of these regime is characterized by one or more intense global dust storms in which the optical depth reaches about 5 over most of

C. B. Leovy; J. E. Tillman; W. R. Guest; J. Barnes

1985-01-01

247

Smectites and related silicates  

NASA Astrophysics Data System (ADS)

This document is part of Subvolume I5a `Phyllosilicates' of Volume 27 `Magnetic properties of non-metallic inorganic compounds based on transition elements' of Landolt-Börnstein - Group III `Condensed Matter'. It presents smectites and related silicates with regard to their crystal structures, lattice parameters, magnetic properties, neutron diffraction data, nuclear gamma resonance (NGR) data, electron spin resonance (ESR) data, nuclear magnetic resonance (NMR) data, electrical resistivities, heat capacities, dielectric properties, X-ray absorption fine-structure (XAFS) studies, infrared and Raman spectra and optical spectra.

Burzo, E.

248

The Weather Dude  

NSDL National Science Digital Library

The Weather Dude is a weather education Web site offered by meteorologist Nick Walker of The Weather Channel. For kids, the site offers a great online textbook entitled Weather Basics, which explains everything from precipitation to the seasons, using simple text and fun graphics. Other fun things for kids include weather songs, questions and quizzes, weather proverbs, and more. Teachers are also provided with helpful resources such as weather activity sheets and printable blank maps, as well as many other links to weather forecasts and information that will help make teaching about weather fun.

Walker, Nick.

2002-01-01

249

21 CFR 172.410 - Calcium silicate.  

Code of Federal Regulations, 2013 CFR

...Drugs 3 2013-04-01 2013-04-01 false Calcium silicate. 172.410 Section 172.410 Food...HUMAN CONSUMPTION Anticaking Agents § 172.410 Calcium silicate. Calcium silicate, including synthetic calcium...

2013-04-01

250

Weathering Effects on the Structures of Mica-Type Clay Minerals.  

National Technical Information Service (NTIS)

Mica-type clay minerals are subjected to an intensive weathering process in the basin of the Willard Reservoir, north of Ogden, on the playa margin of Great Salt Lake. Weathering attacks the interlayer region of the layer lattice silicates most intensivel...

N. Guven P. F. Kerr

1965-01-01

251

Selective weathering of shocked minerals and chondritic enrichment of the Martian fines  

Microsoft Academic Search

In a recent paper, Boslough and Cygan reported the observation of shock-enhanced chemical weathering kinetics of three silicate minerals. Based on the experimental data and on those of Tyburczy and Ahrens for enhanced dehydration kinetics of shocked serpentine, a mechnaism is proposed by which shock-activated minerals are selectively weathered on the surface of Mars. The purpose of the present abstract

M. B. Boslough

1988-01-01

252

Drainage basin weathering and major element transport of two large Chinese rivers (Huanghe and Changjiang)  

Microsoft Academic Search

Long-term records show high concentrations of dissolved major elements in the Changjiang (Yangtze River) and the Huanghe (Yellow River). The Huanghe drainage basin is characterized by intense weathering and erosion of carbonates and evaporites, while weathering and erosion of carbonates and silicates over the drainage basin is the main source of major elements in the Changjiang. The rock\\/soil composition and

Jing Zhang; Wei Wen Huang; Min Guang Liu; Qing Zhou

1990-01-01

253

Chemical weathering in a tropical watershed, Luquillo Mountains, Puerto Rico III: quartz dissolution rates  

Microsoft Academic Search

The paucity of weathering rates for quartz in the natural environment stems both from the slow rate at which quartz dissolves and the difficulty in differentiating solute Si contributed by quartz from that derived from other silicate minerals. This study, a first effort in quantifying natural rates of quartz dissolution, takes advantage of extremely rapid tropical weathering, simple regolith mineralogy,

Marjorie S Schulz; Art F White

1999-01-01

254

Chemical Weathering and the Viking Biology Experiments on Mars  

Microsoft Academic Search

The activity observed by the three Viking lander life detection experiments is reviewed, and the active agents are characterized. It is proposed that the activity in all three experiments may have been caused by a single active agent in the Martian soil, resulting from contemporary chemical weathering of mafic silicates by low-temperature frost and adsorbed H20. Earlier laboratory studies indicated

Robert L. Huguenin

1982-01-01

255

Short Communication: Earth is (mostly) flat, but mountains dominate global denudation: apportionment of the continental mass flux over millennial time scales, revisited  

NASA Astrophysics Data System (ADS)

Carbon dioxide consumption by silicate mineral weathering and the subsequent precipitation of carbonate sediments sequesters CO2 over geologic timescales. The rate of this carbon sequestration is coupled to rates of continental erosion, which exposes fresh minerals to weathering. Steep mountain landscapes represent a small fraction of continental surfaces but contribute disproportionately to global erosion rates. However, the relative contributions of Earth's much vaster, but more slowly eroding, plains and hills remain the subject of debate. Recently, Willenbring et al. (2013) analyzed a compilation of denudation rates and topographic gradients and concluded that low-gradient regions dominate global denudation fluxes and silicate weathering rates. Here, we show that Willenbring et al. (2003) topographic and statistical analyses were subject to methodological errors that affected their conclusions. We correct these errors, and reanalyze their denudation rate and topographic data. In contrast to the results of Willenbring et al. (2013), we find that the denudation flux from the steepest 10% of continental topography nearly equals the flux from the other 90% of the continental surface combined. This new analysis implies global denudation fluxes of ∼23 Gt yr-1, roughly five times the value reported in Willenbring et al. (2013) and closer to previous estimates found elsewhere in the literature. Although low-gradient landscapes make up a small proportion of the global fluxes, they remain important because of the human reliance, and impact, on these vast areas.

Willenbring, J. K.; Codilean, A. T.; Ferrier, K. L.; McElroy, B.; Kirchner, J. W.

2014-01-01

256

Cockpit Weather Information Needs.  

National Technical Information Service (NTIS)

The primary objective is to develop an advanced pilot weather interface for the flight deck and to measure its utilization and effectiveness in pilot reroute decision processes, weather situation awareness, and weather monitoring. Identical graphical weat...

C. H. Scanlon

1992-01-01

257

Forecasting the Weather.  

ERIC Educational Resources Information Center

Presents a computer program which predicts the weather based on student input of such weather data as wind direction and barometric pressure. Also provides procedures for several hands-on, weather-related activities. (JN)

Bollinger, Richard

1984-01-01

258

External Resource: Mechanical Weathering  

NSDL National Science Digital Library

A student activity with teacher's sheet, to give the students an opportunity to realize that all rocks weather mechanically and each specific rock type has its own particular rate of weathering. Mechanical weathering is the process of breaking down bedroc

1900-01-01

259

National Weather Service  

MedlinePLUS

HOME FORECAST Local Graphical Aviation Marine Rivers and Lakes Hurricanes Severe Weather Fire Weather Sun/Moon Long ... LOADING... Menu ? ACTIVE ALERTS ? FORECAST MAPS ? RADAR ? RIVERS, LAKES, RAINFALL ? AIR QUALITY ? SATELLITE ? PAST WEATHER ? Local forecast ...

260

Predicting Weather and Understanding Weather Systems  

NSDL National Science Digital Library

The assignment requires students to observe the weather map in the newspaper for four consecutive days. On the first day they are instructed to choose a location somewhere in the country. The will record the weather conditions there and observe any weather systems that exist elsewhere in the country. They then make predictions of how they expect weather in their location to change over the subsequent three days.

Grandy, Carla

261

Photochemical weathering and contemporary volatile loss on Mars  

NASA Technical Reports Server (NTRS)

In an earlier series of papers by the author it was proposed that photochemical weathering of Fe(2+) in magnetite and in mafic silicates may be occurring in the contemporary surface environment with a resultant loss of O2 from the atmosphere. Morris and Lauer challenged the photochemical weathering model, proposing that oxidation by radiant heating rather than UV photoelectron emission induced oxidation may have dominated in the authors experiments. Subsequent laboratory studies of photochemical weathering of magnetite described here support the authors original proposal that UV illunimation can indeed drive the oxidation of magnetite under contemporary Martian surface conditions. The negative results of the Morris and Lauer study can now be explained.

Huguenin, R. L.

1987-01-01

262

Palmer Automatic Weather Station  

NSF Publications Database

Title : Palmer Automatic Weather Station Type : Antarctic EAM NSF Org: OD / OPP Date : December 06 ... Environmental Action Memorandum (Palmer Automatic Weather Station) To: Files (S.7 - Environment ...

263

Development and initial application of the global-through-urban weather research and forecasting model with chemistry (GU-WRF/Chem)  

NASA Astrophysics Data System (ADS)

A unified model framework with online-coupled meteorology and chemistry and consistent model treatments across spatial scales is required to realistically simulate chemistry-aerosol-cloud-radiation-precipitation-climate interactions. In this work, a global-through-urban WRF/Chem model (i.e., GU-WRF/Chem) has been developed to provide such a unified model framework to simulate these important interactions across a wide range of spatial scales while reducing uncertainties from the use of offline-coupled model systems with inconsistent model treatments. Evaluation against available observations shows that GU-WRF/Chem is capable of reproducing observations with comparable or superior fidelity than existing mesoscale models. The net effect of atmospheric aerosols is to decrease shortwave and longwave radiation, NO2photolysis rate, near-surface temperature, wind speed at 10-m, planetary boundary layer height, and precipitation as well as to increase relative humidity at 2-m, aerosol optical depths, column cloud condensation nuclei, cloud optical thickness, and cloud droplet number concentrations at all scales. As expected, such feedbacks also change the abundance and lifetimes of chemical species through changing radiation, atmospheric stability, and the rates of many meteorologically-dependent chemical and microphysical processes. The use of higher resolutions in progressively nested domains from the global to local scale notably improves the model performance of some model predictions (especially for chemical predictions) and also captures spatial variability of aerosol feedbacks that cannot be simulated at a coarser grid resolution. Simulated aerosol, radiation, and cloud properties exhibit small-to-high sensitivity to various nucleation and aerosol activation parameterizations. Representing one of the few unified global-through-urban models, GU-WRF/Chem can be applied to simulate air quality and its interactions with meteorology and climate and to quantify the impact of global change on urban/regional air quality across various spatial scales.

Zhang, Yang; Karamchandani, Prakash; Glotfelty, Timothy; Streets, David G.; Grell, Georg; Nenes, Athanasios; Yu, Fangqun; Bennartz, Ralf

2012-10-01

264

Reconciling the elemental and Sr isotope composition of Himalayan weathering fluxes: insights from the carbonate geochemistry of stream waters  

Microsoft Academic Search

Determining the relative proportions of silicate vs. carbonate weathering in the Himalaya is important for understanding atmospheric CO2 consumption rates and the temporal evolution of seawater Sr. However, recent studies have shown that major element mass-balance equations attribute less CO2 consumption to silicate weathering than methods utilizing Ca\\/Sr and 87Sr\\/86Sr mixing equations. To investigate this problem, we compiled literature data

ANDREW D. JACOBSON; J OEL D. BLUM; LYNN M. WALTER

2002-01-01

265

Geochemical investigation of weathering processes in a forested headwater catchment: Mass-balance weathering fluxes  

USGS Publications Warehouse

Geochemical research on natural weathering has often been directed towards explanations of the chemical composition of surface water and ground water resulting from subsurface water-rock interactions. These interactions are often defined as the incongruent dissolution of primary silicates, such as feldspar, producing secondary weathering products, such as clay minerals and oxyhydroxides, and solute fluxes (Meunier and Velde, 1979). The chemical composition of the clay-mineral product is often ignored. However, in earlier investigations, the saprolitic weathering profile at the South Fork Brokenback Run (SFBR) watershed, Shenandoah National Park, Virginia, was characterized extensively in terms of its mineralogical and chemical composition (Piccoli, 1987; Pochatila et al., 2006; Jones et al., 2007) and its basic hydrology. O'Brien et al. (1997) attempted to determine the contribution of primary mineral weathering to observed stream chemistry at SFBR. Mass-balance model results, however, could provide only a rough estimate of the weathering reactions because idealized mineral compositions were utilized in the calculations. Making use of detailed information on the mineral occurrence in the regolith, the objective of the present study was to evaluate the effects of compositional variation on mineral-solute mass-balance modelling and to generate plausible quantitative weathering reactions that support both the chemical evolution of the surface water and ground water in the catchment, as well as the mineralogical evolution of the weathering profile. ?? 2008 The Mineralogical Society.

Jones, B. F.; Herman, J. S.

2008-01-01

266

Utilization of Live Localized Weather Information for Sustainable Agriculture  

Microsoft Academic Search

Authors: Jim Anderson VP, Global Network and Business Development WeatherBug® Professional Jeremy Usher Managing Director, Europe WeatherBug® Professional Localized, real-time weather information is vital for day-to-day agronomic management of all crops. The challenge for agriculture is twofold in that local and timely weather data is not often available for producers and farmers, and it is not integrated into decision-support tools

J. Anderson; J. Usher

2010-01-01

267

Regional input to joint European space weather service  

Microsoft Academic Search

The basis for elaborating within COST 724 Action Developing the scientific basis for monitoring modeling and predicting Space Weather European space weather service is rich by many national and international activities which provide instruments and tools for global as well as regional monitoring and modeling COST 724 stimulates coordinates and supports Europe s goals of development and global cooperation by

I. Stanislawska; A. Belehaki; F. Jansen; D. Heynderickx; J. Lilensten; M. Candidi

2006-01-01

268

WeatherNet  

NSDL National Science Digital Library

WeatherNet, brought to us by The Weather Underground at University of Michigan, aims to be the premier site of weather links on the Internet. Besides the topical tropical storm page, you can view Accu-Weathers graphics including Nexrad imagery, satellite photos, surface maps, and forecast maps.

1998-01-01

269

Teaching Weather Concepts.  

ERIC Educational Resources Information Center

Ten exercises based on the weather map provided in the national newspaper "U.S.A. Today" are used to teach intermediate grade students about weather. An overview describes the history of "U.S.A. Today," the format of the newspaper's weather map, and the map's suitability for teaching weather concepts. Specific exercises, which are briefly…

Sebastian, Glenn R.

270

Backyard Weather Station  

NSDL National Science Digital Library

Students use their senses to describe what the weather is doing and predict what it might do next. After gaining a basic understanding of weather patterns, students act as state park engineers and design/build "backyard weather stations" to gather data to make actual weather forecasts.

Integrated Teaching And Learning Program

271

Future Weather Station  

NSDL National Science Digital Library

In this activity students build dioramas of futuristic weather stations to demonstrate their knowledge of weather forecasting. They will work in groups to research modern forecasting equipment and techniques, and then build a weather station that will do something we cannot do at present (such as stopping tornadoes). They will present their dioramas and then discuss the pros and cons of controlling the weather.

272

Weather in Your Life.  

ERIC Educational Resources Information Center

Facts and activities related to weather and meteorology are presented in this unit. Separate sections cover the following topics: (1) the water cycle; (2) clouds; (3) the Beaufort Scale for rating the speed and force of wind; (4) the barometer; (5) weather prediction; (6) fall weather in Iowa (sleet, frost, and fog); (7) winter weather in Iowa…

Kannegieter, Sandy; Wirkler, Linda

273

World weather program: Plan for fiscal year 1972  

NASA Technical Reports Server (NTRS)

The World Weather Program which is composed of the World Weather Watch, the Global Atmospheric Research Program, and the Systems Design and Technological Development Program is presented. The U.S. effort for improving the national weather services through advances in science, technology and expanded international cooperation during FY 72 are described. The activities of the global Atmospheric Research Program for last year are highlighted and fiscal summary of U.S. programs is included.

1971-01-01

274

Supporting Weather Data  

NASA Technical Reports Server (NTRS)

Since its founding in 1992, Global Science & Technology, Inc. (GST), of Greenbelt, Maryland, has been developing technologies and providing services in support of NASA scientific research. GST specialties include scientific analysis, science data and information systems, data visualization, communications, networking and Web technologies, computer science, and software system engineering. As a longtime contractor to Goddard Space Flight Center s Earth Science Directorate, GST scientific, engineering, and information technology staff have extensive qualifications with the synthesis of satellite, in situ, and Earth science data for weather- and climate-related projects. GST s experience in this arena is end-to-end, from building satellite ground receiving systems and science data systems, to product generation and research and analysis.

2004-01-01

275

Analysis of a Sheet Silicate.  

ERIC Educational Resources Information Center

Describes a student project in analytical chemistry using sheet silicates. Provides specific information regarding the use of phlogopite in an experiment to analyze samples for silicon, aluminum, magnesium, iron, potassium, and fluoride. (CS)

Adams, J. M.; Evans, S.

1980-01-01

276

The Silicate Structures: Chalkboard Demonstration  

NSDL National Science Digital Library

Three-dimensional, magnetic representations of SiO tetrahedra and cations are manipulated on a chalkboard to create five basic silicate structures. Students are expected to complete a worksheet accompanying the exercise, which addresses silicate structures, bond types and strengths, physical properties (e.g. fracture, cleavage), Si:O ratio and introduction to vocabulary such as "felsic" and "mafic," and mineral formulae. The worksheet and chalkboard demonstration are designed to simplify silicate structures from complex ball-and-stick models typically used in textbook figures, and to grant students a visual, three-dimensional, manipulable, perspective on what tends to be a confusing concept. This exercise may be simplified or expanded to suit timeframe and the needs of the audience. Benefits of this approach include reinforcement of lecture concepts, broad appeal for a student group with multiple learning styles and degrees of knowledge, and strengthened understanding of the silicate structures.

Stevens, Liane

277

Ion implantation in silicate glasses  

SciTech Connect

This review examines the effects of ion implantation on the physical properties of silicate glasses, the compositional modifications that can be brought about, and the use of metal implants to form colloidal nanosize particles for increasing the nonlinear refractive index.

Arnold, G.W.

1993-12-01

278

Insolation data manual: Long-term monthly averages of solar radiation, temperature, degree-days, and global KT for 248 National Weather Service stations and direct normal solar radiation data manual: Long-term, monthly mean, daily totals for 235 National Weather Service stations  

NASA Astrophysics Data System (ADS)

The Insolation Data Manual presents monthly averaged data which describes the availability of solar radiation at 248 National Weather Service (NWS) stations, principally in the United States. Monthly and annual average daily insolation and temperature values have been computed from a base of 24 to 25 years of data, generally from 1952 to 1975, and listed for each location. Insolation values represent monthly average daily totals of global radiation on a horizontal surface and are depicted using the three units of measurement: kJ/sq m per day, Btu/sq ft per day and langleys per day. Average daily maximum, minimum and monthly temperatures are provided for most locations in both Celsius and Fahrenheit. Heating and cooling degree-days were computed relative to a base of 18.3 C (65 F). For each station, global KT (cloudiness index) values were calculated on a monthly and annual basis. Global KT is an index of cloudiness and indicates fractional transmittance of horizontal radiation, from the top of the atmosphere to the earth's surface. The second section of this volume presents long-term monthly and annual averages of direct normal solar radiation for 235 NWS stations, including a discussion of the basic derivation process. This effort is in response to a generally recognized need for reliable direct normal data and the recent availability of 23 years of hourly averages for 235 stations. The relative inaccessibility of these data on microfiche further justifies reproducing at least the long-term averages in a useful format. In addition to a definition of terms and an overview of the ADIPA model, a discussion of model validation results is presented.

1990-07-01

279

Magnetic study of an Antarctic weathering profile on basalt: Implications for recent weathering on Mars  

NASA Astrophysics Data System (ADS)

In order to better interpret the Martian surface weathering-related mineralogy, we focused on a relevant analogue of the Martian subsurface in terms of lithology and paleoclimate: the Jurassic-aged Ferrar dolerite (Priestley Glacier, Transantarctic Mountains), weathered in cold and dry climate. Together with chemical and mineralogical studies, rock magnetic properties were investigated and completed with Mössbauer measurements. Weathering of the decimetric block is evidenced by chemical profiles showing an increase in Fe content (from 10.5 in the core to 13 wt.% in the surface) and a decrease in Si (from 57 to 53 wt.%, respectively). According to mineralogical, thermomagnetic and hysteresis properties, the main opaque mineral is inherited titanomaghemite, with a concentration about 1%. Enhancement in low field magnetic susceptibility (from 4 · 10 - 6 to 10 · 10 - 6 m 3/kg, respectively) and saturation magnetization (from 0.44 to 0.96 Am 2/kg, respectively) indicates the neoformation of metastable maghemite. Neoformed red ferric (oxy)hydroxides are abundant in the surface. High field susceptibility normalized to iron concentration and Mössbauer spectra indicate a replacement of Fe 2+ from primary silicates (pyroxene) by poorly crystalline antiferromagnetic Fe 3+ (oxy)hydroxides. Thus, highly magnetic titanomaghemite and maghemite coexist with nanosized ferric (oxy)hydroxides and primary silicates, in accordance with Martian in situ observations. Therefore, this study supports the formation of the Martian regolith as resulting from a slow weathering process in near present day conditions.

Chevrier, V.; Mathé, P.-E.; Rochette, P.; Gunnlaugsson, H. P.

2006-04-01

280

Kaolin group and related silicates  

NASA Astrophysics Data System (ADS)

This document is part of Subvolume I5? `Phyllosilicates - Part ?' of Volume 27 `Magnetic properties of non-metallic inorganic compounds based on transition elements` of Landolt-Börnstein - Group III `Condensed Matter'. It presents silicates belonging to the kaolin group and related silicates, presenting their crystal structure and lattice parameters, magnetic properties, nuclear gamma resonance (NGR), nuclear magnetic resonance (NMR) and electron paramagnetic resonance (EPR) data, dielectric properties, heat capacity, infrared and Raman data, and optical absorption spectra.

Burzo, E.

281

Is ``Silicate Life'' Possible?  

NASA Astrophysics Data System (ADS)

The simplest theory of chemical reactions (including also structural isomerisation reactions) is based on the model of potential barrier overcoming which separates combining states (chemical forms) of molecular objects. In a more complicated model not only the zero but other oscillation level positions are taken into account that in the theory of temperature reactions leads to the statistical sum changes on the states. In all traditional models only energetic factors are taken into consideration. A close structural similarity of some organic and silicon organic compositions (for example, paraffins and silans) and similarity of electron building of carbon and silicon atoms, that also reflects in the similarity of their atomic orbitals, were noticed by researchers long ago. These options cause an idea of a possibility of what can be called “the silicate life”. In connection with new visions at the mechanism of the elementary act at chemical reactions there was an opportunity to consider some chemical factors which influence the run of the reactions that earlier had slipped out from the attention.

Gribov, L.; Baranov, V.; Magarshak, Yu.

282

Australian Severe Weather  

NSDL National Science Digital Library

The Australian Severe Weather Web site is maintained by self proclaimed severe weather enthusiasts Michael Bath and Jimmy Deguara. Other weatherphobes will fully appreciate what the authors have assembled. Everything from weather images, storm news, tropical cyclone data, bush fire and wild fire information, weather observation techniques, and even video clips and Web cam links. Although these other items make the site well rounded, the extensive amount of categorized weather pictures (which are quite extraordinary) are reason enough to visit.

283

What's the Weather?  

NSDL National Science Digital Library

In this lesson, students use daily observations, videos, and activities to learn about meteorology and the changing nature of weather. They will also identify weather events that are commonly reported in the news and discuss how weather affects lives. They should understand that weather can change daily and weather patterns change over the seasons, and that it has characteristics that can be measured and predicted. Suggestions for an optional field trip are also provided.

2005-01-01

284

Weathering of phosphorus in black shales  

NASA Astrophysics Data System (ADS)

Rock weathering is the ultimate source of phosphorus (P) to the oceans, where P can be a limiting nutrient for biological production. In this paper, P weathering is examined in soil chronosequences formed in weathering profiles on the organic-rich Woodford Shale, New Albany Shale and Green River Shale. At all sites, organic P and inorganic P concentrations reveal that P weathering is far from complete, prior to erosion. Carbon (C)/P ratios decrease significantly from unweathered shale to the weathered shale at all sites, which is driven by loss of total organic C with weathering. Here we characterize organic phosphorus across a weathering profile from the Woodford Shale using solid-state CPMAS 31P NMR spectroscopy techniques, revealing that P esters are the dominant forms of P during all stages of weathering. Certain P esters appear to be resistant to chemical weathering during the millions of years between deposition, uplift and erosion, possibly representing a significant long-term global sink for P.

Kolowith, Lauren Clark; Berner, Robert A.

2002-12-01

285

Fair weather terrestrial atmospheric electricity  

NASA Astrophysics Data System (ADS)

Atmospheric electricity is one of the oldest experimental topics in atmospheric science. The fair weather aspects, although having less dramatic effects than thunderstorm electrification, link the microscale behaviour of ion clusters to currents flowing on the global scale. This talk will include a survey of some past measurements and measurement methods, as atmospheric electrical data from a variety of sites and eras are now being used to understand changes in atmospheric composition. Potential Gradient data was the original source of information on the global atmospheric electrical circuit, and similar measurements can now be used to reconstruct past air pollution concentrations, and black carbon loading.

Harrison, G.

286

Progress in space weather predictions and applications  

NASA Astrophysics Data System (ADS)

The methods of today's predictions of space weather and effects are so much more advanced and yesterday's statistical methods are now replaced by integrated knowledge-based neuro-computing models and MHD methods. Within the ESA Space Weather Programme Study a real-time forecast service has been developed for space weather and effects. This prototype is now being implemented for specific users. Today's applications are not only so many more but also so much more advanced and user-oriented. A scientist needs real-time predictions of a global index as input for an MHD model calculating the radiation dose for EVAs. A power company system operator needs a prediction of the local value of a geomagnetically induced current. A science tourist needs to know whether or not aurora will occur. Soon we might even be able to predict the tropospheric climate changes and weather caused by the space weather.

Lundstedt, H.

287

Towards quantitative assessment of the hazard from space weather. Global 3-D modellings of the electric field induced by a realistic geomagnetic storm  

NASA Astrophysics Data System (ADS)

In order to estimate the hazard to technological systems due to geomagnetically induced currents (GIC), it is crucial to understand the response of the geoelectric field to a geomagnetic disturbance and to provide quantitative estimates of this field. Most previous studies on GIC and the geoelectric field generated during a geomagnetic storm assume a 1-D conductivity structure of Earth. This assumption however is invalid in coastal regions, where the lateral conductivity contrast is large. In this paper, we investigate the global spatio-temporal pattern of the surface geoelectric field induced by a typical major geomagnetic storm in a conductivity model of Earth with realistic laterally-heterogeneous oceans and continents. Exploiting this model makes the problem fully 3-D. Data from worldwide distributed magnetic observatories are used to construct a realistic model of the magnetospheric source. The results of our numerical studies show large amplification of the geoelectric field in many coastal regions. Peak amplitudes obtained with 3-D modelling exceed the amplitudes obtained in a 1-D model by at least a factor 2, even if the latter makes use of the local vertical conductivity structure. Lithosphere resistivity is a critical parameter, which governs both amplitude and penetration width of the anomalous electric field inland.

Püthe, C.; Kuvshinov, A.

2013-09-01

288

Interactive Weather Information Network  

NSDL National Science Digital Library

Offered by the National Oceanic and Atmospheric Administration (NOAA), the Interactive Weather Information Network (IWIN) is a collection of interactive weather maps and satellite images that is updated every five seconds. Visitors can see cloud cover animation loops, NEXRAD Radar images of precipitation, a map of all current weather fronts, and an interactive national map to see information about any particular state. Other information on the site includes a listing of any active weather warnings, a link for world weather data, and more, making this a must-see site for all those users interested in the most current weather happenings anywhere.

2002-01-01

289

Edheads: Weather Activities  

NSDL National Science Digital Library

This great interactive resource allows you multiple opportunities to explore weather related concepts. After clicking start, you will learn how to report and predict the weather at the underground W.H.E.D weather caves! Each activity has three different levels, and each level is harder than the one before it. This resource also includes a teacher's guide (with pre- and post- tests) and links to additional weather related resources. These include a weather glossary, a Fahrenheit to Celsius & Celsius to Fahrenheit converter, and a link that provides information about interesting people in the weather field.

2010-01-01

290

Pilot weather advisor  

NASA Technical Reports Server (NTRS)

The results of the work performed by ViGYAN, Inc., to demonstrate the Pilot Weather Advisor cockpit weather data system using a broadcast satellite communication system are presented. The Pilot Weather Advisor demonstrated that the technical problems involved with transmitting significant amount of weather data to an aircraft in-flight or on-the-ground via satellite are solvable with today's technology. The Pilot Weather Advisor appears to be a viable solution for providing accurate and timely weather information for general aviation aircraft.

Kilgore, W. A.; Seth, S.; Crabill, N. L.; Shipley, S. T.; Graffman, I.; Oneill, J.

1992-01-01

291

Weather and Precipitation  

NSDL National Science Digital Library

How are different types of weather common in our everyday life? How can we use what we know about weather to go about everyday activities? First, use the Weather Chart to write down what you learn from each website. Then, go to Weather Information Website #1 and click on "What's the Weather?" to dress the bear for the day. Make sure you write it down on your graphic organizer. Next, go to Weather Information Website #3 and explore at least 5(clouds, thunderstorms, winter storms, etc.) of ...

Jones, Ms.

2012-04-12

292

The Weather Man  

NSDL National Science Digital Library

This project is designed to let you be "The Weather Man" and control the weather through simulation, and hands on experience, followed by guided questioning and resource exploration. Form groups of three. Explore the following simulation: Weather Maker Simulator Use the simulation to answer the following questions on paper. 1. How does humility play a role in weather? How does more or less change weather? 2. What is water vapor? Where does it come from? 3. What happens when the weather drops below zero degrees? ...

Grasser, Mrs. E.

2012-09-27

293

The rate and causes of lunar space weathering: Insights from Lunar Reconnaissance Orbiter Wide Angle Camera ultraviolet observations  

NASA Astrophysics Data System (ADS)

Lunar Reconnaissance Orbiter Wide Angle Camera global ultraviolet and visible imaging provides a unique opportunity to examine the rate and causes of space weathering on the Moon. Silicates typically have a strong decrease in reflectance toward UV wavelengths (<~450 nm) due to strong bands at 250 nm and in the far UV. Metallic iron is relatively spectrally neutral, and laboratory spectra suggest that its addition to mature soils in the form of submicroscopic iron (also known as nanophase iron) flattens silicate spectra, significantly reducing spectral slope in the ultraviolet. Reflectance at ultraviolet wavelengths may be especially sensitive to the surface coatings that form due to exposure to space weathering because scattering from the surfaces of grains contributes a larger fraction to the reflectance spectrum at short wavelengths. We find that the UV slope (as measured by the 320/415 nm ratio) is a more sensitive measure of maturity than indexes based on visible and near-infrared wavelengths. Only the youngest features (less than ~100 Ma) retain a UV slope that is distinct from mature soils of the same composition. No craters >20 km have UV slopes that approach those observed in laboratory spectra of fresh lunar materials (powdered lunar rocks). While the 320/415 nm ratio increases by ~18% from powdered rocks to mature soils in laboratory samples, Giordano Bruno, the freshest large crater, only shows a 3% difference between fresh and mature materials. At the resolution of our UV data (400 m/pixel), we observe some small (<5 km) craters that show a ~14% difference in 320/415 nm ratio from their mature surroundings. UV observations show that Reiner Gamma has had significantly lower levels of space weathering than any of the Copernican craters we examined, and was the only region we found with a UV slope that approached laboratory values for fresh powdered rock samples. This is consistent with the hypothesis that its high albedo is due to magnetic shielding from solar wind sputtering effects. Furthermore the observation that all Copernican craters we examined show some degree of space weathering and the extreme immaturity of Reiner Gamma materials show that space weathering of the surface and the resultant modification of UV spectra proceeds at a fast rate and is dominated by solar wind sputtering. Comparisons of the UV trends on other airless bodies (i.e., asteroids and Mercury) may prove fruitful for understanding the relative rates and causes of space weathering across the inner solar system.

Denevi, B. W.; Robinson, M. S.; Sato, H.; Hapke, B. W.; McEwen, A. S.; Hawke, B. R.

2011-12-01

294

Comparative pathology of silicate pneumoconiosis.  

PubMed Central

A simple pneumoconiosis with lamellar birefringent crystals was observed in animals dying in the San Diego Zoo. We studied 100 autopsies from 11 mammalian and eight avian species. In mammals, mild pulmonary lesions comprised crystal-laden macrophages in alveoli and lymphatics. Interstitial fibrosis was present in 20% of cases. There were no nodules. In birds, dust retention produced large granulomas around tertiary bronchi without fibrosis. Mineralogic analysis using scanning and transmission electron microscopy showed most of the crystals to be silicates. Ninety percent were complex silicates, with aluminum-potassium silicates comprising 70% of the analyzed particles. Electron and x-ray diffraction showed the silicates to be muscovite mica and its hydrothermal degradation product, ie, illite clay. This mica was also present on filtration membranes of atmospheric air samples obtained from the San Diego Zoo. The amount of dust retention was related to the animal's age, anatomic or ecologic variances, and length of stay in the San Diego Zoo. Its semidesert atmosphere is rich in silicates, which are inhaled and deposited in the lungs. Similar mica-induced lesions are found in humans living in this region or the Southwest of the USA. This simple pneumoconiosis is likely to be widespread in human populations living in desert or semidesert climates. Images Figure 9 Figure 10 Figure 7 Figure 8 Figure 5 Figure 6 Figure 1 Figure 2 Figure 3 Figure 4

Brambilla, C.; Abraham, J.; Brambilla, E.; Benirschke, K.; Bloor, C.

1979-01-01

295

On Observing the Weather  

NSDL National Science Digital Library

In this article, Mount Washington Observatory meteorologist Tim Markle shares the ins and outs of his daily weather-observing routine and offers insights on making weather observations at home or at school.

Crane, Peter

2004-05-01

296

Weather and Stroke Risk  

MedlinePLUS Videos and Cool Tools

... the lower right-hand corner of the player. Weather and Stroke Risk HealthDay February 13, 2014 Related MedlinePlus Page Stroke Transcript Weather changes may significantly affect stroke risk, a new ...

297

Winter Weather Emergencies  

MedlinePLUS

Severe winter weather can lead to health and safety challenges. You may have to cope with Cold related health problems, including ... there are no guarantees of safety during winter weather emergencies, you can take actions to protect yourself. ...

298

In Depth Winter Weather  

NSDL National Science Digital Library

Winter Weather is an In-Depth Special Report form the National Center for Atmospheric Research. It contains articles, images, activities, video clips, and interactive graphs to inform learners about meteorology and weather in the colder seasons.

2012-01-01

299

Multipurpose Weather Roundup Program.  

National Technical Information Service (NTIS)

Program RWR9 reads Surface Airways Observations (SAO's) from the local AFOS database and reformats them into plain language collectives for Hourly, State, and Regional Weather Roundups. Output is suitable for direct transmission on the state weather wire....

W. E. Sunkel

1983-01-01

300

Favorite Demonstration: Differential Weathering  

NSDL National Science Digital Library

In this inquiry-based demonstration, the consumption of a Baby Ruth candy bar is used to nurture students' interest in chemical and physical weathering. In addition, two other concepts can be illustrated: the difference between weathering and erosion and

Francek, Mark

2002-10-01

301

Weather in Antarctica  

NSDL National Science Digital Library

This homepage includes information about the weather in Antarctica and links to pages on the climate, wind chill, clouds, snow and ice, and pressure and storms of Antarctica. The current weather conditions updated automatically at various stations are also provided.

Hutchings, Thomas

1998-01-01

302

Tectonic Control of Chemical Weathering and CO2 Drawdown in a Steady State Landscape  

NASA Astrophysics Data System (ADS)

We present a combined steady-state chemical weathering model and field-based study that examines the effects of soil depth and uplift rate on chemical weathering rates across a climate/tectonic uplift gradient. This work demonstrates the importance of rock uplift on chemical weathering relative to the effects of precipitation and temperature and shows that climatically focused erosion acts as a driver of silicate weathering, providing a direct link between climate, tectonics, and CO2 drawdown. Our model is applied to the Skykomish river basin in the central Washington Cascades. This drainage basin was selected because previous work (Reiners et al. 2003) has shown that long-term erosion rates in the central Cascades are strongly coupled with modern mean annual precipitation patterns suggesting long-term climatically focused erosion in a steady-state topography. Our analysis of cation fluxes from thirteen catchments within this basin show that silicate weathering is strongly dependent on the rate of supply of easily weathered material and the depth of the zone of weathering. As such, the central Washington Cascades are primarily supply-limited, where weathering-derived Si fluxes are directly related to the rate of rock advection into the zone of active weathering. These data show that chemical weathering is strongly linked to areas of high exhumation, such that CO2 drawdown is approximately 1.5 times higher in areas of rapid exhumation when compared to areas of low exhumation.

Hren, M. T.; Hilley, G.; Chamberlain, C.

2005-12-01

303

Stormfax Weather Services  

NSDL National Science Digital Library

This site offers links to a variety of weather information, including national, international and local weather maps and forecasts, satellite and radar imagery, and severe weather warnings. There are also links to diverse resources such as fire maps, glacier inventories, snow depths, storm surges and tropical storms. There are reports and advisories about El Nino and La Nina. The site also has a glossary of weather terms and conversion charts for temperature, wind speed and atmospheric pressure.

2002-06-10

304

Chemical Weathering, Atmospheric Carbon Fluxes and River Geochemistry of Sandstone of Nanjing Purple Mountain River System, China  

NASA Astrophysics Data System (ADS)

Carbon is the essential element of life on Earth. Weathering of silicate rocks acts as a net carbon sink of the integrated global carbon cycle in the geological time scale. The chemical composition of river can provide us sources of major ions, chemical weathering rates of watershed and the consuming rate of atmospheric carbon dioxide. Accordingly, we choose Nanjing Purple Mountain River System to analyze chemical characteristics of the river water, the consuming rate of atmospheric carbon dioxide and some representative characteristics of rocks and soils. We have got Sodium normalized value for major elements of sandstone weathering, which can provide basis for calculating different endmenbers for large river systems in the world. We found the variation between river water samples, rock samples and soil samples by using several measurement methods and analysis methods. We conclude that: (1) The weathering of sandstone is weak. The contributes of sandstone for river are that Ca/Na:1.5-3, Mg/Na:0.5-1.5, K/Na:0.02-0.1(after sodium normalized). (2) We suggest that there is interference from atmospheric dust input by analyzing those rock samples and soil samples. (3)The rates of chemical weathering are controlled by both temperature and humidity. (4) The consuming rate of atmospheric carbon dioxide is 1.40×105mol/yr. (5) Strontium isotope provides that n(87Sr)/n(86Sr) is between 0.710557×7 and 0.710955×2. Moreover, the concentration of strontium is over 1?mol/L, and the average value is 2.29?mol/L, which suggests that relatively high concentration and isotope ratio.

Zhang, Z.

2013-12-01

305

Weather Maps in Motion  

NSDL National Science Digital Library

In this activity, students learn to interpret current weather maps. They will observe weather map loop animations on the internet, learn the concept of Zulu time (Universal Time Coordinated, UTC) and visualize the movement of fronts and air masses. They will then analyze a specific weather station model, generate a meteogram from their observations, and answer a set of questions about their observations.

Burrows, Charles

306

Aviation weather services  

NASA Technical Reports Server (NTRS)

The primary responsibilities of the National Weather Service (NWS) are to: provide warnings of severe weather and flooding for the protection of life and property; provide public forecasts for land and adjacent ocean areas for planning and operation; and provide weather support for: production of food and fiber; management of water resources; production, distribution and use of energy; and efficient and safe air operations.

Sprinkle, C. H.

1983-01-01

307

Pinpointing the weather  

Microsoft Academic Search

Accurately predicting weather in regions like the west, which have a variety of climates in high mountain, coastal, and desert sites, can be tricky. Now the National Weather Service (NWS) is testing an experimental computer model that will help forecasters predict weather conditions with greater detail. The Eta-10 model allows forecasters in 24 western NWS offices to monitor the development

Elaine Friebele

1997-01-01

308

Hot Weather Tips  

MedlinePLUS

... A A + A You are here Home HOT Weather Tips Printer-friendly version We all suffer in hot weather. However, for elderly and disabled people and those ... conditions such as vascular disease or diabetes, the weather does not have to hit 100 degrees to ...

309

Convective Weather Avoidance with Uncertain Weather Forecasts  

NASA Technical Reports Server (NTRS)

Convective weather events have a disruptive impact on air traffic both in terminal area and in en-route airspaces. In order to make sure that the national air transportation system is safe and efficient, it is essential to respond to convective weather events effectively. Traffic flow control initiatives in response to convective weather include ground delay, airborne delay, miles-in-trail restrictions as well as tactical and strategic rerouting. The rerouting initiatives can potentially increase traffic density and complexity in regions neighboring the convective weather activity. There is a need to perform rerouting in an intelligent and efficient way such that the disruptive effects of rerouting are minimized. An important area of research is to study the interaction of in-flight rerouting with traffic congestion or complexity and developing methods that quantitatively measure this interaction. Furthermore, it is necessary to find rerouting solutions that account for uncertainties in weather forecasts. These are important steps toward managing complexity during rerouting operations, and the paper is motivated by these research questions. An automated system is developed for rerouting air traffic in order to avoid convective weather regions during the 20- minute - 2-hour time horizon. Such a system is envisioned to work in concert with separation assurance (0 - 20-minute time horizon), and longer term air traffic management (2-hours and beyond) to provide a more comprehensive solution to complexity and safety management. In this study, weather is dynamic and uncertain; it is represented as regions of airspace that pilots are likely to avoid. Algorithms are implemented in an air traffic simulation environment to support the research study. The algorithms used are deterministic but periodically revise reroutes to account for weather forecast updates. In contrast to previous studies, in this study convective weather is represented as regions of airspace that pilots are likely to avoid. The automated system periodically updates forecasts and reassesses rerouting decisions in order to account for changing weather predictions. The main objectives are to reroute flights to avoid convective weather regions and determine the resulting complexity due to rerouting. The eventual goal is to control and reduce complexity while rerouting flights during the 20 minute - 2 hour planning period. A three-hour simulation is conducted using 4800 flights in the national airspace. The study compares several metrics against a baseline scenario using the same traffic and weather but with rerouting disabled. The results show that rerouting can have a negative impact on congestion in some sectors, as expected. The rerouting system provides accurate measurements of the resulting complexity in the congested sectors. Furthermore, although rerouting is performed only in the 20-minute - 2-hour range, it results in a 30% reduction in encounters with nowcast weather polygons (100% being the ideal for perfectly predictable and accurate weather). In the simulations, rerouting was performed for the 20-minute - 2-hour flight time horizon, and for the en-route segment of air traffic. The implementation uses CWAM, a set of polygons that represent probabilities of pilot deviation around weather. The algorithms were implemented in a software-based air traffic simulation system. Initial results of the system's performance and effectiveness were encouraging. Simulation results showed that when flights were rerouted in the 20-minute - 2-hour flight time horizon of air traffic, there were fewer weather encounters in the first 20 minutes than for flights that were not rerouted. Some preliminary results were also obtained that showed that rerouting will also increase complexity. More simulations will be conducted in order to report conclusive results on the effects of rerouting on complexity. Thus, the use of the 20-minute - 2-hour flight time horizon weather avoidance teniques performed in the simulation is expected to provide benefits for short-term weather avoidan

Karahan, Sinan; Windhorst, Robert D.

2009-01-01

310

Selective weathering of shocked minerals and chondritic enrichment of the Martian fines  

NASA Technical Reports Server (NTRS)

In a recent paper, Boslough and Cygan reported the observation of shock-enhanced chemical weathering kinetics of three silicate minerals. Based on the experimental data and on those of Tyburczy and Ahrens for enhanced dehydration kinetics of shocked serpentine, a mechnaism is proposed by which shock-activated minerals are selectively weathered on the surface of Mars. The purpose of the present abstract is to argue on the basis of relative volumes of shocked materials that, as a direct consequence of selective weathering, the composition of the weathered surface units on Mars should be enriched in meteoritic material.

Boslough, M. B.

1987-01-01

311

Interactions between carbon dioxide, climate, weathering, and the Antarctic ice sheet in the earliest Oligocene  

NASA Astrophysics Data System (ADS)

A coupled set of models is used to explore the possibility of long-term internal cycles in the CO2–climate–weathering–Antarctic Ice Sheet system. Cycles of this type were found in an earlier study with 0-D box models, and proposed to explain the quasi-periodic oscillations in benthic deep-sea-core records during the Eocene–Oligocene Transition ~ 34 Ma. Here the system is extended using a 3-D Global Climate Model, a 3-D Antarctic ice-sheet model, and two previously published spatially distributed parameterizations of CO2 consumption by silicate weathering. In 6-million year long simulations across an idealized Eocene–Oligocene Transition, no internal cycles are found, and the coupled system just relaxes from the initial state to the final state, with at most one overdamped half-cycle. The absence of cycles is presumably due to features in this 3-D model system that are absent in the 0-D models: powerful Height Mass-Balance Feedback producing strong ice-sheet expansion after initial growth, and hysteresis in ice-sheet response to climate that damps retreat due to moderate warming.

Pollard, D.; Kump, L. R.; Zachos, J. C.

2013-12-01

312

WeatherHawk Weather Station Protocol  

NSDL National Science Digital Library

This resource provides instructions on how to log atmosphere data using a WeatherHawk weather station. A weather station is setup to measure and record atmospheric measurements at 15-minute intervals and can be transferred to the GLOBE program via email. Students can view data for their school that are continuous and show variations within a day. The data collected includes wind speed and direction and pressure thereby supporting a more complete study of meteorology using GLOBE. Students pursue a more extensive set of research investigations.

The GLOBE Program, UCAR (University Corporation for Atmospheric Research)

2003-08-01

313

Reaction of Sodium Hydroxide with Silicate Minerals.  

National Technical Information Service (NTIS)

The reactions of individual silicate minerals with caustic solution were measured over a 1-week period. These silicate minerals included: two feldspars (microcline and albite), two micas (biotite and muscovite), and three clays (chlorite, Kaolinite and mo...

S. D. Thornton

1986-01-01

314

Battery components employing a silicate binder  

DOEpatents

A battery component structure employing inorganic-silicate binders. In some embodiments, casting or coating of components may be performed using aqueous slurries of silicates and electrode materials or separator materials.

Delnick, Frank M. (Albuquerque, NM) [Albuquerque, NM; Reinhardt, Frederick W. (Albuquerque, NM) [Albuquerque, NM; Odinek, Judy G. (Rio Rancho, NM) [Rio Rancho, NM

2011-05-24

315

Fabulous Weather Day  

NSDL National Science Digital Library

Each year, first graders at Kensington Parkwood Elementary School in Kensington, Maryland, look forward to Fabulous Weather Day. After studying weather for three months, we celebrate what we have learned and stretch our thinking further into the weather world around us! Students learn how meteorologists collect data about the weather, how they study wind, temperature, precipitation, basic types/characteristics of clouds, and how they forecast. The project helps the students grow in their understanding of how the weather works and how it can affect their lives. Our unit focused on guiding students to formulate explanations about animals based on scientific evidence.

Marshall, Candice; Mogil, H. M.

2007-01-01

316

External Resource: Weathering and Erosion  

NSDL National Science Digital Library

This activity includes background information about weathering, as well as simple demonstrations/activities to model how weather conditions contribute to weathering and erosion. Topics include: chemical weathering, dunes, erosion, floods, glaciers, physi

1900-01-01

317

Hydrochemical and Isotopic Constraints on the Temporal and Spatial Variability of Chemical Weathering and CO2 Fluxes: An Example From the Australian Victorian Alps  

NASA Astrophysics Data System (ADS)

Water from a network of 11 pristine rivers draining the Australian Victorian Alps was collected at different locations during (i) high discharge (June 2006) and (ii) low discharge (February 2007) conditions and was analyzed for dissolved major ions, ?2H and ?18O, and ?34S of dissolved sulphate. River water chemistry implies that solutes are largely derived from precipitation and chemical weathering of silicate lithologies. Cl/Br ratios as low as 30 molar suggest that rivers have not dissolved halite, however, higher salinity (?100 mmol/L) winter samples have intermediate Cl/Br ratios (600 to 2000 molar) that are attributed to minor halite dissolution at the onset of the rainy season. Subsequent mixing of river water homogenizes ratios and evaporation is the dominant process that increases downstream salinities. Oxygen and Hydrogen isotopes also indicate that mixing and evaporation have occurred. Despite the lack of carbonate outcrops in the study area and uniform negative calcite saturation indices, the dissolution of hydrothermal calcite may account for up to 67% of the total dissolved cations, generating up to 92% of all dissolved Ca and Mg. The sulphur isotope data (16 to 20°CDT) indicates that the dissolved SO4 is derived predominantly from atmospheric deposition and minor gypsum weathering and not from bacterial reduction of FeS. This militates against sulphuric acid weathering in Victorian rivers. Si/(Na* + K*) ratios suggest that silicate weathering is dominated by the transformation of plagioclase (An40) to smectite and, to a lesser extend, the production of kaolinite. In total, chemical weathering consumes 17.6 x 106 (summer) to 71.59 x 106(winter) mol/km2/yr CO2, with the highest values in rivers draining the basement outcrops rather than sedimentary rocks. This range is at the upper end of the global scale and shows that the predominance of fresh silicate lithologies exerts the main control on higher CO2 fluxes; temperature and runoff, in turn, are crucial variables for the inter- seasonal variability in this region. Data on discharge and major ion chemistry, measured in regular intervals between 1977 and 1990, support this; however, the timing of absolute maxima of Si/(Na* + K*) and CO2 flux peaks do not coincide. We suggest that the combination of dissolution of diatoms that precipitated under low flow- and high temperature conditions in the tributaries and Na-adsorption by suspended clay particles, that were probably redistributed locally after bushfires and/or duststorms during drought periods in the early 1980's, as mechanisms to spontaneously elevate Si/(Na* + K*) ratios and, when coupled with irregular discharge fluctuations, explain deviations from seasonal CO2 fluxes.

Hagedorn, B.; Cartwright, I.

2007-12-01

318

Plymouth State Weather Center  

NSDL National Science Digital Library

The Plymouth State Weather Center provides a variety of weather information, including a tropical weather menu with current and archived data on tropical depressions, storms, or hurricanes in the Atlantic or Eastern Pacific Oceans. An interactive Weather Product Generator allows students to make their own surface data maps and meteograms (24-hour summaries of weather at a specific location), and view satellite imagery. There are also interactive weather maps for the U.S., Canada, and Alaska that display the latest observations, and text servers which provide current written observations for New England and North America. A set of past and current weather data products provides information on minimum and maximum temperatures, wind chill, and heat index. In addition, there are collections of satellite loops/movies, radar/lightning images, loops, and movies, and a set of tutorials on clouds, the sun and its effects on the environment, and balanced atmospheric flows.

319

Avalanche Weather Forecasting  

NSDL National Science Digital Library

Avalanches form through the interaction of snowpack, terrain, and weather, the latter being the focus of this module. The module begins with basic information about avalanches, highlighting weather's role in their development. The rest of the module teaches weather forecasters how to make an avalanche weather forecast, that is, one in which key weather parameters are evaluated for their impact on avalanche potential. The forecasts are used primarily by avalanche forecasters, who integrate them with other information to determine when to issue avalanche hazard warnings. The module contains five cases that let users apply the avalanche weather forecast process to different combinations of snowpack, terrain, and weather conditions. It is a companion to the COMET module "Snowpack and Its Assessment," which describes snowpack development and various assessment techniques.

Linder, Dave

2011-01-01

320

Isotopic variations in the recent sediment of the Caspian Sea: a record of Quaternary continental weathering?  

NASA Astrophysics Data System (ADS)

The region of the Caspian Sea was subject to important climatic and sea-level changes during the Late Quaternary, which remain so far still poorly understood. This study presents combined mineralogical, chemical, isotopic (87Sr/86Sr and U-Th disequilibria series) and palynological analyses on bulk sediments and on distinct mineral phases (carbonates and clays) from a 10-m-long core drilled in the southern Caspian Sea and containing Late Pleistocene and Holocene records. The data allowed us to identify 1) the main variations in sedimentations, 2) the processes causing these variations, and possibly 3) the influence of climatic and/or Caspian Sea level changes in the region since the Last Glacial Maximum (LGM). The chemical and mineralogical results allowed the division of the sedimentary sequence into three main units and a transition zone. The lower unit (U1) consists primarily of silicate and carbonate-rich detritus. Sedimentation was relatively constant during U1: the detritus are in secular equilibrium resulting from mechanical erosion in cold climate. U1 corresponds probably to the Khvalynian Transgression, the main transgression in the Caspian Sea during the Late Pleistocene-Early Holocene period. Vegetation cover was sparse and winds were strong. The global increase of temperatures and the decrease of the Caspian water level have modified the sedimentation in the Caspian Sea. Biogenic sedimentation is higher in U2 and U3, and detritus differs from U1. Variations in detrital input are likely caused by decreasing aeolian contribution and by the shrinking of the catchment area of the Caspian Sea. The U-Th disequilibrium of bulk sediments, carbonates and clays has shown an increase of chemical weathering since about 10 ka BP, corresponding to a global warming and to installation of forests in the S and SW of the Caspian Sea watershed. During the same time, the biogenic sedimentation increase strongly, the nature and origin of detrital particles have changed (reflecting for instance decrease of aeolian inputs, change in the catchment area of the main rivers), as well as the physical/chemical weathering ratio. The study of geochemical and isotopic variations in the sediment of the Caspian Sea have allowed to understand the processes having induced these variations: 1) the relation with the Caspian Sea level changes and especially with the Khvalynian transgression, and 2) the influence of the main climatic changes. Our results suggest an evolution of the continental weathering conditions in the drainage basin of the Caspian Sea from mechanical/physical erosion during the cold LMG period to a continuous increase of weathering since about 10,000 yr ago, as climate improved, which illustrates the strong relation between climate, vegetation cover and weathering processes.

Pierret-Neboit, M.; Chabaux, F. J.; Leroy, S.

2010-12-01

321

Tobermorite group of silicates (Text)  

NASA Astrophysics Data System (ADS)

This document is part of Subvolume I4 'Inosilicates' of Volume 27 'Magnetic properties of non-metallic inorganic compounds based on transition elements' of Landolt-Börnstein - Group III Condensed Matter. It contains the data of the tobermorite group of silicates (Text)

Burzo, E.

322

Tobermorite group of silicates (Figures)  

NASA Astrophysics Data System (ADS)

This document is part of Subvolume I4 'Inosilicates' of Volume 27 'Magnetic properties of non-metallic inorganic compounds based on transition elements' of Landolt-Börnstein - Group III Condensed Matter. It contains the data of the tobermorite group of silicates (Figures)

Burzo, E.

323

Tobermorite group of silicates (Tables)  

NASA Astrophysics Data System (ADS)

This document is part of Subvolume I4 'Inosilicates' of Volume 27 'Magnetic properties of non-metallic inorganic compounds based on transition elements' of Landolt-Börnstein - Group III Condensed Matter. It contains the data of the tobermorite group of silicates (Tables)

Burzo, E.

324

Ionic Transport in Liquid Silicates  

Microsoft Academic Search

OME uncertainty exists concerning the presence of semi­ conduction in the electric conduction of liquid silicates. This may be resolved only by measurements of the applicability of Faraday's Laws to the electric transport processes in the melt. Such measurements are considered to be difficult at 800°C in liquid salts.' A method has been devised in these laboratories whereby the oxygen

J. O'M. Bockris; J. A. Kitchener; A. E. Davies

1951-01-01

325

Iron-magnesium silicate bioweathering on Earth (and Mars?).  

PubMed

We examined the common, iron-magnesium silicate minerals olivine and pyroxene in basalt and in mantle rocks to determine if they exhibit textures similar to bioweathering textures found in glass. Our results show that weathering in olivine may occur as long, narrow tunnels (1-3 microm in diameter and up to 100 microm long) and as larger irregular galleries, both of which have distinctive characteristics consistent with biological activity. These weathering textures are associated with clay mineral by-products and nucleic acids. We also examined olivine and pyroxene in martian meteorites, some of which experienced preterrestrial aqueous alteration. Some olivines and pyroxenes in the martian meteorite Nakhla were found to contain tunnels that are similar in size and shape to tunnels in terrestrial iron-magnesium silicates that contain nucleic acids. Though the tunnels found in Nakhla are similar to the biosignatures found in terrestrial minerals, their presence cannot be used to prove that the martian alteration features had a biogenic origin. The abundance and wide distribution of olivine and pyroxene on Earth and in the Solar System make bioweathering features in these minerals potentially important new biosignatures that may play a significant role in evaluating whether life ever existed on Mars. PMID:16551226

Fisk, M R; Popa, R; Mason, O U; Storrie-Lombardi, M C; Vicenzi, E P

2006-02-01

326

Amended Silicated for Mercury Control  

SciTech Connect

Amended Silicates{trademark}, a powdered, noncarbon mercury-control sorbent, was tested at Duke Energy's Miami Fort Station, Unit 6 during the first quarter of 2006. Unit 6 is a 175-MW boiler with a cold-side electrostatic precipitator (ESP). The plant burns run-of-the-river eastern bituminous coal with typical ash contents ranging from 8-15% and sulfur contents from 1.6-2.6% on an as-received basis. The performance of the Amended Silicates sorbent was compared with that for powdered activated carbon (PAC). The trial began with a period of baseline monitoring during which no sorbent was injected. Sampling during this and subsequent periods indicated mercury capture by the native fly ash was less than 10%. After the baseline period, Amended Silicates sorbent was injected at several different ratios, followed by a 30-day trial at a fixed injection ratio of 5-6 lb/MMACF. After this period, PAC was injected to provide a comparison. Approximately 40% mercury control was achieved for both the Amended Silicates sorbent and PAC at injection ratios of 5-6 lbs/MMACF. Higher injection ratios did not achieve significantly increased removal. Similar removal efficiencies have been reported for PAC injection trials at other plants with cold-side ESPs, most notably for plants using medium to high sulfur coal. Sorbent injection did not detrimentally impact plant operations and testing confirmed that the use of Amended Silicates sorbent does not degrade fly ash quality (unlike PAC). The cost for mercury control using either PAC or Amended Silicates sorbent was estimated to be equivalent if fly ash sales are not a consideration. However, if the plant did sell fly ash, the effective cost for mercury control could more than double if those sales were no longer possible, due to lost by-product sales and additional cost for waste disposal. Accordingly, the use of Amended Silicates sorbent could reduce the overall cost of mercury control by 50% or more versus PAC for locations where fly ash is sold as a by-product.

James Butz; Thomas Broderick; Craig Turchi

2006-12-31

327

The effect of temperature on experimental and natural chemical weathering rates of granitoid rocks  

USGS Publications Warehouse

The effects of climatic temperature variations (5-35??C) on chemical weathering are investigated both experimentally using flow-through columns containing fresh and weathered granitoid rocks and for natural granitoid weathering in watersheds based on annual solute discharge. Although experimental Na and Si effluent concentrations are significantly higher in the fresh relative to the weathered granitoids, the proportional increases in concentration with increasing temperature are similar. Si and Na exhibit comparable average apparent activation energies (E(a)) of 56 and 61 kJ/mol, respectively, which are similar to those reported for experimental feldspar dissolution measured over larger temperature ranges. A coupled temperature-precipitation model, using an expanded database for solute discharge fluxes from a global distribution of 86 granitoid watersheds, produces an apparent activation energy for Si (51 kJ/mol), which is also comparable to those derived from the experimental study. This correlation reinforces evidence that temperature does significantly impact natural silicate weathering rates. Effluent K concentrations in the column study are elevated with respect to other cations compared to watershed discharge due to the rapid oxidation/dissolution of biotite. K concentrations are less sensitive to temperature, resulting in a lower average E(a) value (27 kJ/mol) indicative of K loss from lower energy interlayer sites in biotite. At lower temperatures, initial cation release from biotite is significantly faster than cation release from plagioclase. This agrees with reported higher K/Na ratios in cold glacial watersheds relative to warmer temperate environments. Increased release of less radiogenic Sr from plagioclase relative to biotite at increasing temperature produces corresponding decreases in 87Sr/86Sr ratios in the column effluents. A simple mixing calculation using effluent K/Na ratios, Sr concentrations and 87Sr/86Sr ratios for biotite and plagioclase approximates stoichiometric cation ratios from biotite/plagioclase dissolution at warmer temperatures (35??C), but progressively overestimates the relative proportion of biotite with decreasing temperature. Ca, Mg, and Sr concentrations closely correlate, exhibit no consistent trends with temperature, and are controlled by trace amounts of calcite or exchange within weathered biotite. The inability of the watershed model to differentiate a climate signal for such species correlates with the lower temperature dependence observed in the experimental studies.

White, A. F.; Blum, A. E.; Bullen, T. D.; Vivit, D. V.; Schulz, M.; Fitzpatrick, J.

1999-01-01

328

hydrochemistry of the Andeans and sub-andeans Amazon basins - Weathering and CO2 consumption rates.  

NASA Astrophysics Data System (ADS)

Measuring mountain weathering rates, estimating their role on C cycle and identifying the parameters which control them are key to better constrain the knowledge of the continental-ocean-atmosphere interactions over geological timescale. The Andes, in contrast to the Himalaya, have received poor attention in terms of chemical weathering. Several authors have worked on the Amazon river basin, but it is difficult to assess the role of the Andes (10% of the surface area of the Amazon river basin) by only sampling the Amazon at mouth or sampling its largest tributaries. As shown by earlier works, the Upper-Amazon basins are the main matter source of the Amazon basin. The studied area participates at more than 70% of the Amazon weathering rates while it contributes to the total discharge on 30% for 27% of the total area. The studied area is comprised between latitude 0°47'N and 20°28'S and between longitude 79°36'W and 58°45'W and can be divided in three major hydrosystems (the Napo river at North, the Maranon-Ucayali rivers on the central part and the upper Madeira at south) which can be separated on Andes and sub-Andes parts. This work presents the results of the HYBAM research program (present-day hydro-geodynamics of the Amazon Basin) on the upper Amazon basin. The concentration of major elements was analyzed on a monthly basis, sampling at 26 gauging stations which include the Andean basins of the Amazon River and a part of the downstream catchment domain. The objectives of this work are i) calculate the major elements fluxes and their spatial distribution, ii) estimate the present-day rate of rock weathering, as well as the flux of atmospheric/soil CO2 consumption from total rock and silicate weathering, and iii) constrain the major environmental factor which controls the dissolved matter production using unique high temporal and spatial resolution data sampling. The main difficulty of studying large river geochemistry is to separate the main sources of the dissolved matter. Studying the temporal dynamic exportation of each element and their main associations helps to better constrain the main matter origin per sub basins and to identify the main processes of production. Variability of runoff rates and lithology between the 3 hydrosystems mainly explain the intersystem weathering rates variability. o The convergence of high runoff rates and main volcanic lithology on Napo basin implies a high weathering rate compared to other basins of the studied area and the main world basins. o Due to the high presence of evaporites and carbonates rocks, the Maranon and Ucayali hydrosystems controls more than 60% of the Amazon hydrochemistry. o Sandstone lithology and low runoff rates on Upper Madeira basins imply a poor contribution of this basin on Amazon dissolved load. Sub-andean plains basins can take place a major role on weathering balance. On the carbonates basins of Maranon Ucayali the subandes catchments contributes to more than 40% to the dissolved load of the hydrosystem. It can reflect the importance of the weathering of sediments exported from Andes or/and the importance of the upper plain weathering rate. The role of environmental parameters, which control those processes, can be partly constrained over the studied area and are compared to other world results. Those results give new keys to better understand the role of major orogenese zones on global weathering processes and its effect on C cycle.

Moquet, Jean-Sébastien; Crave, Alain; Viers, Jérome; Guyot, Jean-Loup; Lagane, Christelle; Sven Lavado Casimiro, Waldo; Pombosa, Rodrigo; Noriega, Luis; Chavary, Eduardo

2010-05-01

329

Iron Isotope Fractionation in Artic Weathering Environments  

NASA Astrophysics Data System (ADS)

While our current knowledge of Fe isotope systematics in rivers is still limited, Fe isotopes provide a new approach to important questions concerning Fe sources, Fe speciation and its bioavailability in the hydrological cycles. Here, we investigated several Arctic rivers for elemental and Fe-isotopic composition with specific emphasis on silicate weathering and organic C content in order to provide new insights into the delivery of trace nutrients, such as Fe, that are important for the biological productivity of the Arctic Ocean. Without such characterization of the present state of the system, future changes in the response of these river systems to global change cannot be properly evaluated. Our Fe isotope systematics results in Siberian rivers, include (1) a time-series of water samples from large rivers (Ob and Lena) focusing on the peak flow that has not yet been investigated despite its critical importance for annual budgets; (2) the colloidal fractions (1 kDa to 0.45 ?m) of rivers and their estuaries in the White Sea, including the Severnaya Dvina River to assess the influence of Fe-rich colloids flocculation on the Fe isotopic composition of the estuarine waters. Dissolved iron fractions (<0.22 ?m) in large rivers have restricted ?56Fe values, with the Ob River varying from -0.29 to 0.01‰, averaging -0.11‰ (n= 20) and the Lena River varying from -0.24 to -0.01‰, averaging -0.11‰ (n=15). These values are slightly lower than bulk silicate earth values (defined at 0.09‰ relative to IRMM-14) and do not display any relationships with ice break-up on the rivers. In contrast, dissolved iron fractions in the Severnaya Dvina River and its tributaries yield more positive ?56Fe values, with values ranging from -0.09 to up to 0.64‰, averaging 0.2‰ (n=19). Small swamp rivers from the South White Sea coast reveal an even higher spread of dissolved ?56Fe values, from -1.1 to +0.8‰ with some clear variations among the various colloidal fractions (1 kDa-10 kDa - 100 kDa). These results, together with the high Fe and DOC concentrations in the water samples, suggest that Fe-redox cycling in soil aquifer, as well as the formation of organic-rich colloids, may impart specific Fe-isotope signatures in dissolved Fe reaching the Artic Ocean. Recent studies (e.g. Fantle and De Paolo, 2004 and Bergquist and Boyle, 2006) have demonstrated that rivers present an isotopically light Fe source to the oceans. Our study further suggests that ?56Fe composition of Artic rivers is not unique and depending on Fe speciation in organo- mineral colloids and their origin, may be characterized by more positive and negative ?56Fe values relative to the crust than previously reported.

Rouxel, O. J.; Escoube, R.; Pokrovsky, O. S.; Wisch, M.; Miller, C.

2008-12-01

330

Weather and Atmosphere  

NSDL National Science Digital Library

In this unit, students learn the basics about weather and the atmosphere. They investigate materials engineering as it applies to weather and the choices available to us for clothing to counteract the effects of weather. Students have the opportunity to design and analyze combinations of materials for use in specific weather conditions. In the next lesson, students also are introduced to air masses and weather forecasting instrumentation and how engineers work to improve these instruments for atmospheric measurements on Earth and in space. Then, students learn the distinguishing features of the four main types of weather fronts that accompany high and low pressure air masses and how those fronts are depicted on a weather map. During this specific lesson, students learn different ways that engineers help with storm prediction, analysis and protection. In the final lesson, students consider how weather forecasting plays an important part in their daily lives by learning about the history of weather forecasting and how improvements in weather technology have saved lives by providing advance warning of natural disasters.

Integrated Teaching And Learning Program

331

Chemical weathering in the Krishna Basin and Western Ghats of the Deccan Traps, India: Rates of basalt weathering and their controls  

Microsoft Academic Search

Rates of chemical and silicate weathering of the Deccan Trap basalts, India, have been determined through major ion measurements in the headwaters of the Krishna and the Bhima rivers, their tributaries, and the west flowing streams of the Western Ghats, all of which flow almost entirely through the Deccan basalts.Samples (n = 63) for this study were collected from 23

A. Das; S. Krishnaswami; M. M. Sarin; K. Pande

2005-01-01

332

Space Weathering of Rocks  

NASA Technical Reports Server (NTRS)

Space weathering discussions have generally centered around soils but exposed rocks will also incur the effects of weathering. On the Moon, rocks make up only a very small percentage of the exposed surface and areas where rocks are exposed, like central peaks, are often among the least space weathered regions we find in remote sensing data. However, our studies of weathered Ap 17 rocks 76015 and 76237 show that significant amounts of weathering products can build up on rock surfaces. Because rocks have much longer surface lifetimes than an individual soil grain, and thus record a longer history of exposure, we can study these products to gain a deeper perspective on the weathering process and better assess the relative impo!1ance of various weathering components on the Moon. In contrast to the lunar case, on small asteroids, like Itokowa, rocks make up a large fraction of the exposed surface. Results from the Hayabusa spacecraft at Itokowa suggest that while the low gravity does not allow for the development of a mature regolith, weathering patinas can and do develop on rock surfaces, in fact, the rocky surfaces were seen to be darker and appear spectrally more weathered than regions with finer materials. To explore how weathering of asteroidal rocks may differ from lunar, a set of ordinary chondrite meteorites (H, L, and LL) which have been subjected to artificial space weathering by nanopulse laser were examined by TEM. NpFe(sup 0) bearing glasses were ubiquitous in both the naturally-weathered lunar and the artificially-weathered meteorite samples.

Noble, Sarah

2011-01-01

333

Chemical Weathering in a Tropical Watershed, Luquillo Mountains, Puerto Rico: I. Long-Term Versus Short-Term Weathering Fluxes  

Microsoft Academic Search

The pristine Rio Icacos watershed in the Luquillo Mountains in eastern Puerto Rico has the fastest documented weathering rate of silicate rocks on the Earth’s surface. A regolith propagation rate of 58 m Ma?1, calculated from iso-volumetric saprolite formation from quartz diorite, is comparable to the estimated denudation rate (25–50 Ma?1) but is an order of magnitude faster than the

Art F. White; Alex E. Blum; Marjorie S. Schulz; Davison V. Vivit; David A. Stonestrom; Matthew Larsen; Sheila F. Murphy; D. Eberl

1998-01-01

334

Effects of ionization on silicate glasses. [Silicate glasses  

SciTech Connect

This evaluation of radiation effects in silicate glasses caused by ionization is based on our own investigations, on material collected in our files (reports, articles, and notes), and on a computer literature search through recent issues of Physics Abstracts and Chemical Abstracts (and the apparently pertinent references which appeared). Some of our recent results, available heretofore only in internal correspondence, are presented in some detail. It is concluded that research into the behavior of silicate glasses generally will be required before the specific effects in the radioactive waste storage glasses can be properly understood and evaluated. Two particular neglected areas of investigation are targeted for immediate concern: a kinetic analysis of annealing data and the acquisition of data on effects of irradiation at controlled elevated temperatures.

Primak, W.

1982-02-01

335

Cometary Silicates: Interstellar and Nebular Materials  

NASA Technical Reports Server (NTRS)

Evidence for interstellar material in comets is deduced from IR spectra, insitu measurements of Halley, and chondritic porous interplanetary dust particles (CP IDPs). IR spectra of comets reveal the spectrally active minerals: amorphous carbon, amorphous silicates, and (in some comets) crystalline silicates. Evidence suggests amorphous silicates are of interstellar origin while crystalline silicates are of nebular origin. 10 microns spectra of comets and submicron amorphous silicate spherules in CP IDPs have shapes similar to lines-of-sight through the ISM. Thermal emission models of cometary IR spectra require Fe-bearing amorphous silicates. Fe-bearing amorphous silicates may be Fe-bearing crystalline silicates formed in AGB outflows that are amorphized through He+ ion bombardment in supernova shocks in the ISM. Crystalline silicates in comets, as revealed by IR spectra, and their apparent absence in the ISM, argues for their nebular origin. The high temperatures (less than l000 K) at which crystals form or are annealed occur in the inner nebula or in nebular shocks in the 5-10 AU region. Oxygen isotope studies of CP IDPs show by mass only 1 % of the silicate crystals are of AGB origin. Together this suggests crystalline silicates in comets are probably primitive grains from the early solar nebula.

Wooden, Diane H.

2002-01-01

336

NOAA Daily Weather Maps  

NSDL National Science Digital Library

The charts on this website are the principal charts of the former Weather Bureau publication, "Daily Weather Map." They are the Surface Weather Map, the 500-Millibar Height Contours chart, the Highest and Lowest Temperatures chart, and the Precipitation Areas and Amounts chart. For each day, simple charts are arranged on a single page. These charts are the surface analysis of pressure and fronts, color shading, in ten degree intervals,of maximum and minimum temperature, 500-Millibar height contours, and color shaded 24-hour total precipitation. These charts act as links to their respective Daily Weather Map charts. All charts are derived from the operational weather maps prepared at the National Centers for Environmental Prediction, Hydrometeorological Prediction Center, National Weather Service.

Center, Hydrometeorological P.

2011-01-01

337

Climate Change and Farm Use of Weather Information  

Microsoft Academic Search

More rapid than normal global climate change as represented by rising temperatures and more erratic and severe weather events have heightened the interest in how farmers use weather information. The greenhouse influence through driving climate change will likely be affecting agricultural efforts for some years to come. It behooves us to pay attention to this phenomenon, and especially put effort

Ikrom S. Artikov; Gary D. Lynne

2005-01-01

338

Projected Changes in Extreme Weather and Climate Events in Europe  

Microsoft Academic Search

Extreme weather and climate events have wide ranging impacts on society as well as on biophysical systems. That society, on occasions, is unable to cope with extreme weather and climate events is concerning, especially as increases in the frequency and intensity of certain events are predicted by some global climate change projections. Extreme events come in many different shapes and

Glenn McGregor; Christopher Ferro; David Stephenson

339

Weather Changing Waves Chartered from Space  

NSDL National Science Digital Library

This article explains how the TOPEX/Poseidon satellite has been used to track large-scale ocean waves called Rossby waves. This new data indicates that the waves may move faster than previously thought, which may have implications for global weather forecasting. Links to related sites are provided.

340

Weather and Climate Data  

NSDL National Science Digital Library

The Weather and Climate Data site for the Center for Ocean-Land-Atmosphere Studies (COLA) contains analyses of current conditions and the state of the atmosphere; weather forecasts; metropolitan quick-look weather summaries and meteograms; short-term climate outlooks for temperature, precipitation and soil moisture; El Nino forecasts for understanding the ocean-atmosphere system; and maximum potential hurricane intensity maps showing potential minimum pressure and potential maximum winds for the oceans.

341

WWW - Wonderful Web Weather  

NSDL National Science Digital Library

This is a web quest for students to research weather forecasting using the Internet. Students work in groups to study how accurate weather forecasts are by tracking the weather for 3 days in several locations. Using graphs students then compare how each location scored in accuracy and present their findings to the class. This site contains links for students to use for more background information, a process for the students to follow, and evaluation rubrics for the student-produced graphs and presentation.

Parrish, Jason

342

RBSP Space Weather data  

NASA Astrophysics Data System (ADS)

On August 23, 2012, NASA will launch two identical probes into the radiation belts to provide unprecedented insight into the physical processes and dynamics of near-Earth space. The RBSP mission in addition to the scientific data return, provides a 1Kbps real-time space weather broadcast data in support of real time space weather modeling, forecast and prediction efforts. Networks of ground stations have been identified to downlink the space weather data. The RBSP instrument suites have selected space weather data to be broadcast from their collected space data on board the spacecraft, a subset from measurements based on information normally available to the instrument. The data subset includes particle fluxes at a variety of energies, and magnetic and electric field data. This selected space weather data is broadcast at all times through the primary spacecraft science downlink antennas when an observatory is not in a primary mission-related ground contact. The collected data will resolve important scientific issues and help researchers develop and improve various models for the radiation belts that can be used by forecasters to predict space weather phenomena and alert astronauts and spacecraft operators to potential hazards. The near real-time data from RBSP will be available to monitor and analyze current environmental conditions, forecast natural environmental changes and support anomaly resolution. The space weather data will be available on the RBSP Science Gateway at http://athena.jhuapl.edu/ and will provide access to the space weather data received from the RBSP real-time space weather broadcast. The near real-time data will be calibrated and displayed on the web as soon as possible. The CCMC will ingest the RBSP space weather data into real-time models. The raw space weather data will be permanently archived at APL. This presentation will provide a first look at RBSP space weather data products.

Weiss, M.; Fox, N. J.; Mauk, B. H.; Barnes, R. J.; Potter, M.; Romeo, G.; Smith, D.

2012-12-01

343

National Weather Service  

NSDL National Science Digital Library

Sick and tired of the heat? Feel like it will never end? Then check out the National Weather Service's (NWS) Heat Wave, a site devoted to the extreme weather that is crippling the south. The NWS provides information on the heat index, heat's affect on the body, and how to beat the heat. For those who want an up-to-the-minute look at the weather, the site links to current conditions, forecasts, and watches and warnings.

344

Backyard Weather Stations  

NSDL National Science Digital Library

Learn how to build your own backyard weather station with complete directions provided by FamilyEducation.com's Web site, Backyard Weather Stations. The site shows exactly what you'll need and how to build the necessary components (e.g., rain gauge and barometer), as well as how to keep records of the data collected. Parents and teachers will enjoy watching the kids "learn the basics of scientific observation and record-keeping while satisfying their natural curiosity about weather."

Randall, Dennis.

345

Winter weather activity  

NSDL National Science Digital Library

This project explores factors that help create severe winter weather. An interactive simulation provides hands-on experience, followed by guiding questions and resource exploration. Weather Maker Simulator Use the weather simulation above to answer the following questions in complete sentences on paper. 1. In general, when are winds formed? 2. When winds are blowing, how can you get them to stop? 3. What usually happens when there is a large difference between the temperatures? 4. What happens when there is high ...

Frankovic, Whitney

2009-09-28

346

Everything Weather- Archived Data  

NSDL National Science Digital Library

Users can obtain current weather forecasts for their own areas by entering a ZIP code, or they can access a large archive of historic data on severe weather (tornadoes, hail, high winds, hurricanes). Materials presented in the archive include dates, times, and intensities of storms, a photo gallery, maps, radar and other satellite data, storm chaser reports, and links to other weather sites. Raw data can be found in several forms for teachers wishing to have unprocessed data to work with.

2001-01-01

347

Weather and climate  

NASA Technical Reports Server (NTRS)

Recommendations for using space observations of weather and climate to aid in solving earth based problems are given. Special attention was given to: (1) extending useful forecasting capability of space systems, (2) reducing social, economic, and human losses caused by weather, (3) development of space system capability to manage and control air pollutant concentrations, and (4) establish mechanisms for the national examination of deliberate and inadvertent means for modifying weather and climate.

1975-01-01

348

Mineralogy of Natural Basalt Weathering Rinds With Application to Thermal Emission Spectra of Mars  

NASA Astrophysics Data System (ADS)

Mineralogy of Natural Basalt Weathering Rinds With Application to Thermal Emission Spectra of Mars M.D. Kraft, J.R. Michalski, T.G. Sharp, (and P.R. Christensen?) Chemically weathered rocks have been suggested to cover a significant portion of the Martian surface based on orbiter observations, and rocks investigated by the Mars Exploration Rover at the Gusev landing site show evidence of chemical alteration and weathering rinds. To understand remote mineralogical and chemical measurements of altered rock surfaces, whether in situ or from orbit, it is important to understand the general characteristics of weathering rinds (e.g., secondary mineralogy and microstructure in rinds) and how these characteristics affect remote observations. We are investigating a suite of weathered rocks of the Columbia River Basalt Group (CRBG) to identify chemical, mineralogical, and micro-structural changes associated with weathering and determine how these changes influence thermal emission measurements. Preliminary work shows that thermal emission spectra of weathered surfaces can vary substantially from spectra of fresh rocks despite rather low degrees of alteration in weathered surfaces. In rocks studied thus far, the predominant difference between the unweathered rock and weathering rind is an increase in porosity in the rind due to dissolution and/or volume expansion, causing a substantial increase in the volume density of micron-scale cracks. Mineralogical differences are imparted in the rind by the (partial) infilling of cracks by secondary materials that are Si, Al, and Fe-rich. A previous investigation by Colman (1982) showed that secondary silicates in basalt weathering rinds were dominantly X-ray amorphous. High-resolution secondary electron imaging of crack-filling products reveals spheroid-shaped materials, 10s of nm in diameter, which are consistent with short-range order allophane. We are currently performing additional analyses using XRD and TEM to constrain the mineralogy of secondary phases in CRGB weathering rinds, including the crystallinity of secondary silicates. Assessing chemical weathering on Mars may rely largely on the ability to detect and constrain the mineralogy of short-range order silicates, which may be the dominant Martian weathering products. Thermal emission spectroscopic data of Mars, with the detailed understanding that we intend to provide with this study, provides a unique and excellent means of constraining the nature of silicate weathering on Mars.

Kraft, M. D.; Michalski, J. R.; Sharp, T. G.; Christensen, P. R.

2004-12-01

349

Weather or Not?  

NSDL National Science Digital Library

Weather or Not? is part of an online series of modules entitled Exploring the Environment. Emphasizing an integrated approach to environmental Earth Science education through problem-based learning, this module asks students to monitor the current weather and make predictions for up to a week. Using satellite imagery and monitoring resources, students predict the weather for an up-coming event of their choice (such as a sporting event). After the predictions are made, students track the actual weather that occurred during the event. There are links and resources for further information and research, as well as a reference on problem-based learning.

350

Washington Post Weather  

NSDL National Science Digital Library

The Washington Post makes a bid for the already crowded Internet weather market with WeatherPost. Coverage includes current conditions and four-day forecasts for 3,600 cities worldwide, as well as snapshot and time-lapse satellite maps (provided by Accu Weather). For US cities, users may also access UV and air quality maps and data, as well as seasonal maps (snow cover, tanning index, heat index, and BeachCast) and other radar images such as precipitation. Users may enter a city name into the homepage search box, or may browse by country or state/province. The historical weather database offers compiled monthly average weather data for nearly 1,000 cities worldwide; the database is searchable. An aspect of the site that sets it apart from many other weather pages is the weather reference desk, which includes a weather glossary, weather calculators (JavaScript converters for temperature, wind chill, heat index, etc.) and a page devoted to storm chasers.

1997-01-01

351

Winter Storm (weather)  

NSDL National Science Digital Library

This project explores factors that help create severe winter weather. An interactive simulation provides hands-on experience, followed by guiding questions and resource exploration. First think about these questions: 1. What is your favorite aspect of winter weather? 2. How does the weather effect your everyday life? Form groups of THREE. Explore the following simulation: Weather Maker Simulator Use the simulation to answer the following questions on paper... 1. In general, when are winds formed? 2. When winds are blowing, how can you ...

Miller, Aubree

2009-09-28

352

The Weather and Climate Toolkit  

NASA Astrophysics Data System (ADS)

The Weather and Climate Toolkit (WCT) is free, platform independent software distributed from NOAA’s National Climatic Data Center (NCDC). The WCT allows the visualization and data export of weather and climate data, including Radar, Satellite and Model data. By leveraging the NetCDF for Java library and Common Data Model, the WCT is extremely scalable and capable of supporting many new datasets in the future. Gridded NetCDF files (regular and irregularly spaced, using Climate-Forecast (CF) conventions) are supported, along with many other formats including GRIB. The WCT provides tools for custom data overlays, Web Map Service (WMS) background maps, animations and basic filtering. The export of images and movies is provided in multiple formats. The WCT Data Export Wizard allows for data export in both vector polygon/point (Shapefile, Well-Known Text) and raster (GeoTIFF, ESRI Grid, VTK, Gridded NetCDF) formats. These data export features promote the interoperability of weather and climate information with various scientific communities and common software packages such as ArcGIS, Google Earth, MatLAB, GrADS and R. The WCT also supports an embedded, integrated Google Earth instance. The Google Earth Browser Plugin allows seamless visualization of data on a native 3-D Google Earth instance linked to the standard 2-D map. Level-II NEXRAD data for Hurricane Katrina GPCP (Global Precipitation Product), visualized in 2-D and internal Google Earth view.

Ansari, S.; Del Greco, S.; Hankins, B.

2010-12-01

353

Brittle micas and related silicates  

NASA Astrophysics Data System (ADS)

This document is part of Subvolume I5a `Phyllosilicates' of Volume 27 `Magnetic properties of non-metallic inorganic compounds based on transition elements' of Landolt-Börnstein - Group III `Condensed Matter'. It presents brittle micas and related silicates with regard to their crystal structures, lattice parameters, nuclear gamma resonance (NGR) data, nuclear magnetic resonance (NMR) data, X-ray absorption spectra and optical properties.

Burzo, E.

354

Pyrophyllite, talc and related silicates  

NASA Astrophysics Data System (ADS)

This document is part of Subvolume I5a `Phyllosilicates' of Volume 27 `Magnetic properties of non-metallic inorganic compounds based on transition elements' of Landolt-Börnstein - Group III `Condensed Matter'. It presents pyrophyllite, talc and related silicates with regard to their crystal structures, lattice parameters, neutron diffraction data, magnetic properties, nuclear gamma resonance (NGR) data, nuclear magnetic resonance (NMR) data, heat capacities and optical properties.

Burzo, E.

355

Modulation of Late Cretaceous and Cenozoic climate by variable drawdown of atmospheric pCO2 from weathering of basaltic provinces on continents drifting through the equatorial humid belt  

NASA Astrophysics Data System (ADS)

The small reservoir of carbon dioxide in the atmosphere (pCO2) that modulates climate through the greenhouse effect reflects a delicate balance between large fluxes of sources and sinks. The major long-term source of CO2 is global outgassing from sea-floor spreading, subduction, hotspot activity, and metamorphism; the ultimate sink is through weathering of continental silicates and deposition of carbonates. Most carbon cycle models are driven by changes in the source flux scaled to variable rates of ocean floor production. However, ocean floor production may not be distinguishable from being steady since 180 Ma. We evaluate potential changes in sources and sinks of CO2 for the past 120 Ma in a paleogeographic context. Our new calculations show that although decarbonation of pelagic sediments in Tethyan subduction likely contributed to generally high pCO2 levels from the Late Cretaceous until the Early Eocene, shutdown of Tethyan subduction with collision of India and Asia at the Early Eocene Climate Optimum at around 50 Ma was inadequate to account for the large and prolonged decrease in pCO2 that eventually allowed the growth of significant Antarctic ice sheets by around 34 Ma. Instead, variation in area of continental basaltic provinces in the equatorial humid belt (5° S-5° N) seems to be the dominant control on how much CO2 is retained in the atmosphere via the silicate weathering feedback. The arrival of the highly weatherable Deccan Traps in the equatorial humid belt at around 50 Ma was decisive in initiating the long-term slide to lower atmospheric pCO2, which was pushed further down by the emplacement of the 30 Ma Ethiopian Traps near the equator and the southerly tectonic extrusion of SE Asia, an arc terrane that presently is estimated to account for 1/4 of CO2 consumption from all basaltic provinces that account for ~1/3 of the total CO2 consumption by continental silicate weathering (Dessert et al., 2003). A negative climate-feedback mechanism that (usually) inhibits the complete collapse of atmospheric pCO2 is the accelerating formation of thick cation-deficient soils that retard chemical weathering of the underlying bedrock. Nevertheless, equatorial climate seems to be relatively insensitive to pCO2 greenhouse forcing and thus with availability of some rejuvenating relief as in arc terranes or thick basaltic provinces, silicate weathering in this venue is not subject to a strong negative feedback, providing an avenue for sporadic ice ages. The safety valve that prevents excessive atmospheric pCO2 levels is the triggering of silicate weathering of continental areas and basaltic provinces in the temperate humid belt. Increase in Mg/Ca ratio of seawater over the Cenozoic may be due to weathering input from continental basaltic provinces.

Kent, D. V.; Muttoni, G.

2012-09-01

356

Insolation data manual: Long-term monthly averages of solar radiation, temperature, degree-days and global K(sub T) for 248 National Weather Service stations and Direct normal solar radiation data manual: Long-term, monthly mean, daily totals for 235 National Weather Service stations. Addendum to the Insolation data manual.  

National Technical Information Service (NTIS)

The Insolation Data Manual presents monthly averaged data which describes the availability of solar radiation at 248 National Weather Service (NWS) stations, principally in the United States. Monthly and annual average daily insolation and temperature val...

1990-01-01

357

Germanium-silicon fractionation in the weathering environment  

NASA Astrophysics Data System (ADS)

We present a detailed study of germanium behavior in the soil weathering environment as an important step toward using the Ge/Si system as a tracer of silicate weathering processes in both modern and ancient environments. Intensely weathered soils developed on Hawaiian basalts have bulk soil Ge/Si ratios 2 to 10 times higher than fresh basalt (e.g., 10 to 25 ?mol/mol vs. 2.5 ?mol/mol). Soil Ge concentrations increase with Si, and decrease with Fe, suggesting that Ge sequestration is related to accumulation of secondary soil silicates, rather than retention in soil Fe oxy-hydroxides. Sequential extractions of these soils suggest that Ge/Si fractionation takes place by Ge sequestration during the initial precipitation of secondary soil aluminosilicates (principally allophane). Further Si loss and changes in mineralogy as these soils age result in little additional Ge/Si fractionation. Ge/Si ratios in granitic soils and saprolites are strongly influenced by relative weathering rates of primary minerals. Kaolinite has a Ge/Si ratio (5.9 ?mol/mol) higher than the plagioclase from which it forms (3.1 ?mol/mol), whereas accumulation of primary quartz (Ge/Si 0.5 ?mol/mol) prevents granitic soils from attaining high Ge/Si ratios. Laboratory synthesis of allophane confirms that Ge is preferentially partitioned into the solid phase upon precipitation of secondary aluminosilicates from solution.

Kurtz, Andrew C.; Derry, Louis A.; Chadwick, Oliver A.

2002-05-01

358

Mild and Wild Weather.  

ERIC Educational Resources Information Center

Presents background information and six activities that focus on clouds, precipitation, and stormy weather. Each activity includes an objective, recommended age level(s), subject area(s), and instructional strategies. Also provided are two ready-to-copy pages (a coloring page on lightning and a list of weather riddles to solve). (JN)

NatureScope, 1985

1985-01-01

359

People and Weather.  

ERIC Educational Resources Information Center

Provides: (1) background information on ways weather influences human lives; (2) activities related to this topic; and (3) a ready-to-copy page with weather trivia. Each activity includes an objective, list of materials needed, recommended age level(s), subject area(s), and instructional strategies. (JN)

NatureScope, 1985

1985-01-01

360

Basics of Weather Models.  

National Technical Information Service (NTIS)

Without using mathematics, this memo summarizes the important information weather forecasters need to know to apply numerical weather prediction (NWP) forecasts. We've had to make some tough choices regarding what material to include. We've put the more t...

W. D. Meyer

1993-01-01

361

Home Weatherization Visit  

ScienceCinema

Secretary Steven Chu visits a home that is in the process of being weatherized in Columbus, OH, along with Ohio Governor Ted Strickland and Columbus Mayor Michael Coleman. They discuss the benefits of weatherization and how funding from the recovery act is having a direct impact in communities across America.

362

Home Weatherization Visit  

ScienceCinema

Secretary Steven Chu visits a home that is in the process of being weatherized in Columbus, OH, along with Ohio Governor Ted Strickland and Columbus Mayor Michael Coleman. They discuss the benefits of weatherization and how funding from the recovery act is having a direct impact in communities across America.

Chu, Steven

2013-05-29

363

Northwest Weather Watch  

NSDL National Science Digital Library

This educational module is designed to teach students about predicting weather. This includes a series of activites about clouds, moisture, air and rain for students to complete. There are curriculum connections to art, writing and math as well as links for more resources and live weather data.

Palewicz, Sue; Scurlock, Marianne; Edmon, Harry

364

On Observing the Weather  

ERIC Educational Resources Information Center

Rain, sun, snow, sleet, wind... the weather affects everyone in some way every day, and observing weather is a terrific activity to attune children to the natural world. It is also a great way for children to practice skills in gathering and recording information and to learn how to use simple tools in a standardized fashion. What better way to…

Crane, Peter

2004-01-01

365

Weathering Database Technology  

ERIC Educational Resources Information Center

Collecting weather data is a traditional part of a meteorology unit at the middle level. However, making connections between the data and weather conditions can be a challenge. One way to make these connections clearer is to enter the data into a database. This allows students to quickly compare different fields of data and recognize which…

Snyder, Robert

2005-01-01

366

Fabulous Weather Day  

ERIC Educational Resources Information Center

Each year, first graders at Kensington Parkwood Elementary School in Kensington, Maryland, look forward to Fabulous Weather Day. Students learn how meteorologists collect data about the weather, how they study wind, temperature, precipitation, basic types/characteristics of clouds, and how they forecast. The project helps the students grow in…

Marshall, Candice; Mogil, H. Michael

2007-01-01

367

Weather Fundamentals: Wind. [Videotape].  

ERIC Educational Resources Information Center

The videos in this educational series, for grades 4-7, help students understand the science behind weather phenomena through dramatic live-action footage, vivid animated graphics, detailed weather maps, and hands-on experiments. This episode (23 minutes) describes the roles of the sun, temperature, and air pressure in creating the incredible power…

1998

368

Weather Vane and Anemometer  

NSDL National Science Digital Library

In this meteorology activity, learners construct simple devices to measure the direction and speed of wind. Learners will explore wind and air resistance as well as how weather vanes and generators work to analyze weather patterns. Note: a drill and other specialty tools are required for this activity, but are not included in the cost of materials.

Workshop, Watsonville E.

2011-01-01

369

Erosion and Weathering  

NSDL National Science Digital Library

Weathering and erosion work together as natural forces, removing and transporting material. Sediments, the by-products of these processes, are subsequently deposited to produce characteristic landforms such as dunes, deltas, and glacial moraines. This slide show presents images of landforms that result from erosion and weathering, as well as measures designed to mitigate their unwanted effects.

370

Aviation Weather Program (AWP)  

NASA Technical Reports Server (NTRS)

The Aviation Weather Program (AWP) combines additional weather observations, improved forecast technology, and more efficient distribution of information to pilots, controllers, and automated systems to improve the weather information provided to the air traffic control system, pilots, and other users of aviation weather information. Specific objectives include the needs to: improve airport and en-route capacity by accurate, high resolution, timely forecasts of changing weather conditions affecting airport and en-route operations; improve analyses and forecasts of upper-level winds for efficient flight planning and traffic management; and increase flight safety through improved aviation weather hazard forecasting (e.g. icing, turbulence, severe storms, microbursts, or strong winds). The AWP would benefit from participation in a cooperative multiscale experiment by obtaining data for: evaluation of aviation weather forecast products, analysis of four dimensional data assimilation schemes, and experimental techniques for retrieving aerosol and other visibility parameters. A multiscale experiment would also be helpful to AWP by making it possible to evaluate the added benefit of enhanced data sets collected during the experiment on those forecast and analysis products. The goals of the Coperative Multiscale Experiment (CME) are an essential step in attaining the long-term AWP objective of providing two-to-four hour location-specific forecasts of significant weather. Although the possibility of a funding role for the AWP in the CME is presently unclear, modest involvement of Federal Aviation Administration (FAA)/AWP personnel could be expected.

Foote, Brant

1993-01-01

371

Weathering of Serpentine Aggregates.  

National Technical Information Service (NTIS)

This report deals with the rapid weathering of serpentine aggregates in an autoclave-type device. Samples of serpentine aggregate from three sources were subjected to ten weathering cycles each and the results were compared with the resistance to rapid we...

1965-01-01

372

Benign Weather Modification.  

National Technical Information Service (NTIS)

Weather modification is a technology once embraced by the United States (US) military as a tool to help both wartime and peacetime missions. However, interest in the ability to modify weather has waned over recent years and is now nearly nonexistent. This...

B. B. Coble

1997-01-01

373

Benign Weather Modification.  

National Technical Information Service (NTIS)

Weather modification is a technology once embraced by the U.S. military as a tool to help both wartime and peacetime missions. However, interest in the ability to modify weather has waned over recent years and is now nearly non-existent. This study examin...

B. E. Coble

1996-01-01

374

Scholastic: Weather Watch  

NSDL National Science Digital Library

The Weather Watch series of online projects investigates seasonal weather phenomena. Students discover the scientific explanations for these events, and use tools and resources for enhanced research. The Hurricanes project allows students to monitor patterns and plot the progression of hurricanes. The Winter Storms project contains an interactive weather maker allowing students to create different weather patterns by changing factors. A winter storm timeline provides stories of the harshest blizzards that have occurred in the U.S. The Weather Reporters project includes a selection of hands-on science experiments for classroom participation, leading up to sharing results online with students worldwide. Each project provides assessment tools and lesson plan suggestions for educators. Links are provided for additional resources.

375

Mars surface weathering products and spectral analogs: Palagonites and synthetic iron minerals  

NASA Technical Reports Server (NTRS)

There are several hypotheses regarding the formation of Martian surface fines. These surface fines are thought to be products of weathering processes occurring on Mars. Four major weathering environments of igneous rocks on Mars have been proposed; (1) impact induced hydrothermal alterations; (2) subpermafrost igneous intrusion; (3) solid-gas surface reactions; and (4) subaerial igneous intrusion over permafrost. Although one or more of these processes may be important on the Martian surface, one factor in common for all these processes is the reaction of solid or molten basalt with water (solid, liquid, or gas). These proposed processes, with the exception of solid-gas surface reactions, are transient processes. The most likely product of transient hydrothermal processes are layer silicates, zeolites, hydrous iron oxides and palagonites. The long-term instability of hydrous clay minerals under present Martian conditions has been predicted; however, the persistence of such minerals due to slow kinetics of dehydration, or entrapment in permafrost, where the activity of water is high, can not be excluded. Anhydrous oxides of iron (e.g., hematite and maghemite) are thought to be stable under present Martian surface conditions. Oxidative weathering of sulfide minerals associated with Martian basalts has been proposed. Weathering of sulfide minerals leads to a potentially acidic permafrost and the formation of Fe(3) oxides and sulfates. Weathering of basalts under acidic conditions may lead to the formation of kaolinite through metastable halloysite and metahalloysite. Kaolinite, if present, is thought to be a thermodynamically stable phase at the Martian surface. Fine materials on Mars are important in that they influence the surface spectral properties; these fines are globally distributed on Mars by the dust storms and this fraction will have the highest surface area which should act as a sink for most of the absorbed volatiles near the surface of Mars. Therefore, the objectives of this study were to: (1) examine the fine fraction mineralogy of several palagonitic materials from Hawaii; and (2) compare spectral properties of palagonites and submicron sized synthetic iron oxides with the spectral properties of the Martian surface.

Golden, D. C.; Ming, D. W.; Morris, R. V.; Lauer, H. V., Jr.

1992-01-01

376

A Weathering Index for CK and R Chondrites  

NASA Technical Reports Server (NTRS)

We present a new weathering index (wi) for the metallic-Fe-Ni-poor chondrite groups (CK and R) based mainly on transmitted light observations of the modal abundance of crystalline material that is stained brown in thin sections: wi-0, <5 vol%; wi-1, 5-25 vol%; wi-2,25-50 vol%; wi-3,50- 75 vol%; wi-4, 75-95 vol%; wi-5, >95 vol%, wi-6, significant replacement of mafic silicates by phyllosilicates. Brown staining reflects mobilization of oxidized iron derived mainly from terrestrial weathering of Ni-bearing sulfide. With increasing degrees of terrestrial weathering of CK and R chondrites, the sulfide modal abundance decreases, and S, Se, and Ni become increasingly depleted. In addition, bulk Cl increases in Antarctic CK chondrites, probably due to contamination from airborne sea mist.

Rubin, Alan E.; Huber, Heinz

2006-01-01

377

Insensitivity of weathering behavior to planetary land fraction and effect on habitability  

NASA Astrophysics Data System (ADS)

It is likely that an increasing number of terrestrial planets of unknown water content will soon be discovered in the habitable zone of their stars. Planetary surface land fraction may, however, influence the functioning of the silicate weathering feedback, which buffers planetary surface climate against changes in stellar luminosity over a star's lifetime. It is therefore worthwhile to consider the effect of land fraction on the planetary carbon cycle and weathering behavior in a general sense. Here a low-order model of weathering and climate is developed that includes both continental silicate weathering and seafloor weathering. This model can be used to gain an intuitive sense of the behavior of terrestrial planets with different land fractions in the habitable zone of main-sequence stars as their star's insolation changes with time. It is found that, as long as seafloor weathering is independent of surface temperature, there can be no weathering feedback on a waterworld. This means that the tenure of a waterworld in the habitable zone (before it undergoes a moist greenhouse) is likely to be much shorter than that of a planet with some land fraction. The silicate weathering feedback, however, is effective even at very low land fractions. A planet with a land fraction of 0.01 should remain in the habitable zone nearly as long as a planet with a land fraction of 0.3. Finally, by comparing the timescale for water loss to space to the weathering timescale, it is found that it is possible for a waterworld to draw down atmospheric CO2 quickly enough as a moist greenhouse is in progress to prevent complete loss of all water. This would imply that waterworlds in the habitable zone of main sequence stars can go through a moist greenhouse stage and end up as planets like Earth with only partial ocean coverage and a habitable climate.

Abbot, D. S.; Archer, D.; Pierrehumbert, R. T.; Ciesla, F. J.; Bean, J. L.

2012-04-01

378

Silicon Kedge XANES spectra of silicate minerals  

Microsoft Academic Search

Silicon K-edge x-ray absorption near-edge structure (XANES) spectra of a selection of silicate and aluminosilicate minerals have been measured using synchrotron radiation (SR). The spectra are qualitatively interpreted based on MO calculation of the tetrahedral SiO44-cluster. The Si K-edge generally shifts to higher energy with increased polymerization of silicates by about 1.3 eV, but with considerable overlap for silicates of

Dien Li; G. M. Bancroft; M. E. Fleet; X. H. Feng

1995-01-01

379

SEDIMENTATION AND WETTABILITY OF SYNTHETIC MAGNESIUM SILICATES  

Microsoft Academic Search

In the paper studies were presented which aimed at obtaining synthetic magnesium silicate, which could be applied as a selective adsorbent, polymer filler or a filler of paper-coating masses. Synthetic magnesium silicate was obtained by precipitation using solutions of MgSO4·7H2O and Na2SiO3 (water glass). In view of specific application of the precipitated silicates, the process of their production was broadened

Filip CIESIELCZYK; Andrzej KRYSZTAFKIEWICZ; Teofil JESIONOWSKI

2006-01-01

380

Analysis of Preflight Weather Briefings.  

National Technical Information Service (NTIS)

Weather is often cited as a factor in general aviation (GA) accidents and mishaps. The type of weather information requested from, or provided by, automated flight service station (AFSS) specialists is dependent on weather conditions at the time the prefl...

A. M. Hendrix O. V. Prinzo R. Hendrix

2007-01-01

381

Hypothermia: A Cold Weather Hazard  

MedlinePLUS

... cold air. But, not everyone knows that cold weather can also lower the temperature inside your body. ... cold it is where you are. Check the weather forecasts for windy and cold weather. Try to ...

382

Oceans Effect on Weather and Climate  

NSDL National Science Digital Library

The Ocean's Effect on Weather and Climate SciPack explores concepts related to Earth's weather and climate. The focus is on Standards and Benchmarks related to weather and climate, the water cycle, climate change, and the role of solar energy and its affect on the atmosphere and oceans. The unique role oceans play in defining Earth's weather and climate patterns is also specifically addressed. In addition to comprehensive inquiry-based learning materials tied to Science Education Standards and Benchmarks, the SciPack includes the following additional components:� Pedagogical Implications section addressing common misconceptions, teaching resources and strand maps linking grade band appropriate content to standards. � Access to one-on-one support via e-mail to content "Wizards".� Final Assessment which can be used to certify mastery of the concepts.Learning Outcomes:Ocean's Effect on Weather and Climate: Global Climate Patterns� Explain why the temperature of the ocean does not generally fluctuate as dramatically as the temperature of the land.� Describe the relationship between density of liquids and gases and their temperature.� Explain how a difference in density of different layers/portions of a fluid will cause internal currents (rising and falling of the fluid).� Explain the cause of predictable wind patterns along the coastal regions of large land masses.� Describe how the Coriolis Effect helps determine the direction of movement of air and water currents.� List the major variables that affect the transfer of energy through the atmosphere.� Provide an example showing how the transfer of energy affects weather and climate.� Explain how convection relates to weather, including its role in the development of circulation patterns. Ocean's Effect on Weather and Climate: Global Precipitation and Energy� Outline the basic steps in the water cycle in terms of density, energy of the water, and the relative molecular arrangement and motion in each phase.� Describe how energy is transferred to the atmosphere by heating from the ocean and by the evaporation of water and its subsequent condensation. � Identify the Sun as the energy source that drives atmospheric circulation and the movement of masses of air and water from one place on Earth to another (via convection).� Llist sources for the water cycle and identify the largest source.� Explain the relationship between water, temperature, the amount of water evaporated into the atmosphere (and subsequently condensed), and the energy of the atmosphere at or near the location of evaporation.Ocean's Effect on Weather and Climate: Global Circulation Patterns� Explain how the oceans might influence and affect local weather and climate, given a specific location (on the planet near the ocean) and the local ocean currents.� Describe the cause of hurricanes and explain why they usually occur within specific regions during certain times of the year.� Explain how changes in ocean temperatures (over a period of months) affect factors that influence weather patterns.� List the major variables that affect the transfer of energy through the ocean.Ocean's Effect on Weather and Climate: Changing Climate� Explain the role that phenomena such as volcanic eruptions or asteroid impact play in changing climate.� Describe the type of atmospheric conditions and weather related data that can be obtained from ice core and deep-sea sediment records.� Describe how a small change in the content of oceans and atmosphere (such as a rise in carbon dioxide levels) can have significant impacts on global climate.� Describe human activity that has an affect on climate.

National Science Teachers Association (NSTA)

2007-03-28

383

Effect of silicate ions on electrode overvoltage  

NASA Technical Reports Server (NTRS)

The influence of the addition of a silicate to a caustic solution (KOH) is studied in order to determine the degree to which silicates inhibit the corrosion of chrysotile under conditions of electrolysis at working temperatures of 100 C and above. In an alkaline solution containing various silicate concentrations, current density was increased and electrode overvoltage was measured. Results show that silicate ion concentrations in the electrolyte increase with temperature without effecting electrochemical performance up to 115 C at 700 MA/sqcm. At this point the concentration is about 0.5 g Si/100 g KOH. Beyond this limit, electrolytic performance rapidly degenerates due to severe oxidation of the electrodes.

Gras, J. M.; Seite, C.

1979-01-01

384

Space Weather CD  

NSDL National Science Digital Library

This is a software package about space weather: what it is and what it does in space and here on Earth. The disc includes software that displays movies and images of the aurora and of the Sun in various wavelengths from the ground and from orbiting NASA spacecraft; a tutorial about what space weather is and how the aurora is formed; and more. Users will also find real-time space weather conditions from current satellite missions and can download the latest data without leaving the Space Weather application. A TicTacToe game is also included that tests space weather knowledge. The disc contains many other Space Weather resources, programs, sounds, and games for use at home or school, and there are several educational websites included in full on the disc for offline viewing. In addition there is an exhaustive list of links to a variety of space weather resources available online. The disc is available for free from a number of sites if downloaded.

385

Models for silicate melt viscosity  

NASA Astrophysics Data System (ADS)

The prediction of viscosity in silicate liquids, over the range of temperatures and compositions encountered in nature, remains one of the most challenging and elusive goals in Earth Sciences. Recent work has demonstrated that there are now sufficient experimental measurements of melt viscosity to create new viscosity models to replace previous Arrhenian models [1],[2] and extend the compositional range of more recent non-Arrhenian models [3]. Most recently, [4] have developed an empirical strategy for accurately predicting viscosities over a very wide range of anhydrous silicate melt compositions (e.g., rhyolite to basanite). Future models that improve upon this work, will probably extend the composition range of the model to consider, at least, H2O and other volatile components and may utilize a compositional basis that reflects melt structure. In preparation for the next generation model, we explore the attributes of the three most common equations that could be used to model the non-Arrhenian viscosity of multicomponent silicate melts. The equations for the non-Arrhenian temperature dependence of viscosity (? ) include: a) Vogel-Fulcher-Tammann (VFT): log ? = A + B/(T - C) b) Adam and Gibbs (AG): log ? = A + B/[T log (T/C)], and c) Avramov (Av): log ? = A + [B/T]? We use an experimental database of approximately 900 high-quality viscosity measurements on silicate melts to test the ability of each equation to capture the experimental data. These equations have different merits [5]. VFT is purely empirical in nature. The AG model has a quasi-theoretical basis that links macroscopic transport properties directly to thermodynamic properties via the configurational entropy. Lastly, the model proposed by Avramov adopts a form designed to relate the fit parameter (? ) to the fragility of the melt. [1] Shaw, H.R., 1972. Am J Science, 272, 438-475. [2] Bottinga Y. and Weill, D., 1972. Am J Science, 272, 438-475. [3] Hess, K.U. and Dingwell, D.B, 1996, Am Min, 81, 1297-1300. [4] D. Giordano & D.B. Dingwell, 2003. EPSL. 208, 337 (and related corrige EPSL 221, 449) [5] J.K. Russell, D. Giordano & D.B. Dingwell, 2003. Am Min 88, 1390

Giordano, D.; Russell, K.; Moretti, R.; Mangiacapra, A.; Potuzak, M.; Romano, C.; Dingwell, D. B.

2004-12-01

386

Weathering and Erosion  

NSDL National Science Digital Library

This Classroom Connectors lesson plan discusses weather conditions and their contribution to weathering and erosion. Students learn to explain the process of physical and chemical weathering. They also learn to compare and contrast erosion resulting from wind, ice and water. The site provides goals, objectives, an outline, time required, materials, activities, and closure ideas for the lesson. The Classroom Connectors address content with an activity approach while incorporating themes necessary to raise the activity to a higher cognition level. The major motivation is to employ instructional strategies that bring the students physically and mentally into touch with the science they are studying.

387

Wonderful World of Weather  

NSDL National Science Digital Library

This standards-based Real Time Data Module was created by the Center for Improved Engineering and Science Education (CIESE) for use by students in the elementary grades to allow them to investigate weather phenomena both locally as well as in other places around the world. By using hands-on activities and real-time data investigations, the students will develop a basic understanding of how weather can be described in measurable quantities, such as temperature, wind and precipitation. The site features a Teacher Area containing lesson plans, curriculum standards, guidelines for data collection, and a list of children's books with weather-related themes.

388

Extreme Weather Sourcebook 2001  

NSDL National Science Digital Library

Originally reviewed in the February 26, 1999 Scout Report, the latest version of the National Center for Atmospheric Research (NCAR) Extreme Weather Sourcebook offers easy access to updated data on the economic damage from hurricanes, floods, and tornadoes in the United States and its territories. Time spans for each type of extreme weather vary, with hurricane data covering 1900-99, tornadoes 1950-99, floods 1955-1999, and lightning 1959-1994; however, all damage data are reported in constant 1999 dollars to simplify comparisons. The data are offered by weather event and state by rank or alphabetically.

2001-01-01

389

Wonderful World of Weather  

NSDL National Science Digital Library

This website uses real time data for many activities for learning about the weather. It can be modified to fit virtually any grade level. The project is broken up into 3 sets of lessons; Introductory Activities, Real Time Data Activities, and Language Arts Activities. Each lesson gives a recommended time for completion, to help keep students and teachers on track. There is a helpful teachers guide section with background information about real time data, curriculum standards, and assessment suggestions. Th students gallery has many examples of real projects other students have already created. There is also a helpful reference guide, with information on real time weather, projects, and weather lesson plans.

2006-01-01

390

Solar structure and terrestrial weather  

NASA Technical Reports Server (NTRS)

The possibility that solar activity has discernible effects on terrestrial weather is considered. Research involving correlation of weather conditions with solar and geomagnetic activity is discussed.

Wilcox, J. M.

1976-01-01

391

GEOSS interoperability for Weather, Ocean and Water  

NASA Astrophysics Data System (ADS)

"Understanding the Earth system — its weather, climate, oceans, atmosphere, water, land, geodynamics, natural resources, ecosystems, and natural and human-induced hazards — is crucial to enhancing human health, safety and welfare, alleviating human suffering including poverty, protecting the global environment, reducing disaster losses, and achieving sustainable development. Observations of the Earth system constitute critical input for advancing this understanding." With this in mind, the Group on Earth Observations (GEO) started implementing the Global Earth Observation System of Systems (GEOSS). GEOWOW, short for "GEOSS interoperability for Weather, Ocean and Water", is supporting this objective. GEOWOW's main challenge is to improve Earth observation data discovery, accessibility and exploitability, and to evolve GEOSS in terms of interoperability, standardization and functionality. One of the main goals behind the GEOWOW project is to demonstrate the value of the TIGGE archive in interdisciplinary applications, providing a vast amount of useful and easily accessible information to the users through the GEO Common Infrastructure (GCI). GEOWOW aims at developing funcionalities that will allow easy discovery, access and use of TIGGE archive data and of in-situ observations, e.g. from the Global Runoff Data Centre (GRDC), to support applications such as river discharge forecasting.TIGGE (THORPEX Interactive Grand Global Ensemble) is a key component of THORPEX: a World Weather Research Programme to accelerate the improvements in the accuracy of 1-day to 2 week high-impact weather forecasts for the benefit of humanity. The TIGGE archive consists of ensemble weather forecast data from ten global NWP centres, starting from October 2006, which has been made available for scientific research. The TIGGE archive has been used to analyse hydro-meteorological forecasts of flooding in Europe as well as in China. In general the analysis has been favourable in terms of forecast skill and concluded that the use of a multi-model forecast is beneficial. Long term analysis of individual centres, such as the European Centre for Medium-Range Weather Forecasts (ECMWF), has been conducted in the past. However, no long term and large scale study has been performed so far with inclusion of different global numerical models. Here we present some initial results from such a study.

Richardson, David; Nyenhuis, Michael; Zsoter, Ervin; Pappenberger, Florian

2013-04-01

392

Tombstone Weathering Lab  

NSDL National Science Digital Library

Students work in groups in a cemetery to collect a quantitative and a qualitative measure of the extent of weathering of tombstones and their ages. The data are shared between all students, graphed as scatter plots, and the rate of weathering is estimated. Students write about and then discuss the results, the difference between the quantitative and qualitative measures, and speculate on factors in addition to time that may be important for weathering rate. The exercise ends with each students writing a hypothesis about a factor that influences weathering rate and describing a research project that could test that hypothesis. This activity is aimed at developing an understanding of the scatter in "real data", allowing for practice of team work, and hypothesis generation and testing. Designed for a geomorphology course Has minimal/no quantitative component

Anders, Alison

393

Wasatch Weather Modification Project.  

National Technical Information Service (NTIS)

The primary objective of the Wasatch Weather Modification Project is to 'assess the relative effectiveness and the practicability of selected procedures for increasing the water supply, from precipitation in the Wasatch Mountains, by cloud seeding.' A loc...

G. W. Reynolds

1969-01-01

394

Cold-Weather Sports  

MedlinePLUS

Ahh, winter! Shorter days. Frigid temperatures. Foul weather. What better time to be outdoors? Winter sports can help you burn calories, increase your cardiovascular fitness, and strengthen muscles. Activities that are ...

395

Weather and Climate.  

National Technical Information Service (NTIS)

Recommendations for using space observations of weather and climate to aid in solving earth based problems are given. Special attention was given to: (1) extending useful forecasting capability of space systems, (2) reducing social, economic, and human lo...

1975-01-01

396

Garments, Outer (Wet Weather).  

National Technical Information Service (NTIS)

The report describes a method for evaluation of wet weather clothing operational and functional performance characteristics. Identifies supporting tests, facilities, and equipment required. Provides procedures for preoperational inspection, physical chara...

R. Rush

1972-01-01

397

Cold Weather Aerostat Study.  

National Technical Information Service (NTIS)

Aerostats are being considered for application in cold weather regions. A review of aerostat flight experience to date was made to determine the limitations of the current technology. Areas for improvements and modifications to extend the aerostat system ...

R. L. Ashford

1982-01-01

398

Accelerated Weathering of Rocks.  

National Technical Information Service (NTIS)

The project concerns correlation between weathering indices obtained from samples of one type of sedimentary rock (graywacke) and those obtained after laboratory agency tests of the same rocks. Study is made of the process of natural alteration in three s...

L. Aires-Barros

1977-01-01

399

Northern latitude chemical weathering rates: clues from the Mackenzie River Basin, Canada  

NASA Astrophysics Data System (ADS)

The main scope of this study is to investigate parameters controlling chemical weathering rates for a large river system submitted to subarctic climate. More than 110 river water samples from the Mackenzie River system (northern Canada) have been sampled and analyzed for major and trace elements and Sr isotopic ratios in the dissolved phase. The three main morphological units are reflected in water chemistry. Rivers from the Canadian Shield are very dilute, dominated by silicate weathering (Millot et al., 2002), whereas the rivers of the Rocky and Mackenzie Mountains as well as the rivers of the sedimentary Interior Platform are dominated by carbonate weathering and are SO 4 rich. Compared to the rivers of the Mackenzie and Rocky Mountains, the rivers of the interior plains are organic, silica, and Na rich and constitute the dominant input term to the Mackenzie River mainstream. Rivers of the Canadian Shield area do not significantly contribute to the Mackenzie River system. Using elemental ratios and Sr isotopic ratios, a mathematical inversion procedure is presented that distinguishes between solutes derived from silicate weathering and solutes derived from carbonate weathering. Carbonate weathering rates are mostly controlled by runoff, which is higher in the mountainous part of the Mackenzie basin. These rates are comparable to the carbonate weathering rates of warmer areas of the world. It is possible that part of the carbonate weathering is controlled by sulfide oxidative weathering, but its extent remains difficult to assess. Conversely to what was stated by Edmond and Huh (1997), overall silicate weathering rates in the Mackenzie basin are low, ranging from 0.13 to 4.3 tons/km 2/yr (Na + K + Ca + Mg), and confirm the negative action of temperature on silicate weathering rates for river basins in cold climates. In contrast to what has been observed in other large river systems such as the Amazon and Ganges Rivers, silicate weathering rates appear 3 to 4 times more elevated in the plains than in the mountainous headwaters. This contradicts the "Raymo hypothesis" (Raymo and Ruddiman, 1992). Isotopic characterization of suspended material clearly shows that the higher weathering rates reported for the plains are not due to the weathering of fine sediments produced in the mountains (e.g., by glaciers) and deposited in the plains. Rather, the relatively high chemical denudation rates in the plains are attributed to lithology (uncompacted shales), high mechanical denudation, and the abundance of soil organic matter derived from incomplete degradation and promoting crystal lattice degradation by element complexation. The three- to fourfold factor of chemical weathering enhancement between the plains and mountains is similar to the fourfold factor of enhancement found by Moulton et al. (2000) between unvegetated and vegetated watershed. This study confirms the negative action of temperature on silicate weathering for cold climate but shows that additional factors, such as organic matter, associated with northern watersheds are able to counteract the effect of temperature. This acceleration by a factor of 4 in the plains is equivalent to a 6°C increase in temperature.

Millot, Romain; Gaillardet, J. érôme; Dupré, Bernard; Allègre, Claude Jean

2003-04-01

400

Windows on the Weather  

NASA Astrophysics Data System (ADS)

Windows on the Weather is a web-based teaching tool designed to engage middle school students in the analysis and understanding of Earth's atmosphere by combining current weather satellite imagery with live webcams from across the United States. This project lends itself to inquiry-based studies in a variety of Earth science disciplines, including meteorology, climatology, and geography. This paper describes the project as it currently stands, along with features to be implemented in the future.

Alena, T. R.

2010-08-01

401

NOAA Weather Education  

NSDL National Science Digital Library

NOAA offers links to a variety of educational materials on meteorology, hydrology, climatology, and other weather-related fields for children, teens, and young adults at this website. Students can find websites where they can learn about hurricanes, storms, tornadoes, and floods through interactive games. Teachers can find lightning safety presentations, satellite images, lightning photos, and glossaries. The website offers materials on weather related careers, degree programs, distance learning courses, and additional opportunities.

402

Weathering of Minerals  

NSDL National Science Digital Library

Students determine the % change in mass of mineral samples that have been placed in a rock tumbler. They graph the relationship between the hardness of the mineral and the % change in mass. They then consider why some of the mineral samples do not conform the the relationship they graphed. They investigate the physical properties of the outliers and consider how the physical properties contributed to the rate of weathering, and what kind of weathering occured in the rock tumbler.

Van Norden, Wendy

403

TypoWeather  

NSDL National Science Digital Library

The TypoWeather application is a great way to stay on top of the latest weather conditions. This handy device presents users with a five day outlook and an hourly breakdown that is updated based on data from the National Meteorological Service. Visitors can customize their layout to include alerts about certain meteorological conditions, such as wind patterns, humidity, and more. This version is compatible with all operating systems.

2014-03-13

404

Extreme Weather Sourcebook: Tornadoes  

NSDL National Science Digital Library

The Extreme Weather Sourcebook is a database maintained by the Societal Impacts Program (SIP) at NCAR of statistics on extreme weather events. The Sourcebook is intended as a resource for researchers, policy makers, the media, and the general public, among other users. This page from the Sourcebook showcases data on tornado damages as total losses for the years 1950-2009 in the United States.

University Consortium for Atmospheric Research (UCAR)

405

40 CFR 721.9513 - Modified magnesium silicate polymer (generic).  

Code of Federal Regulations, 2010 CFR

... false Modified magnesium silicate polymer (generic). 721.9513 Section 721...721.9513 Modified magnesium silicate polymer (generic). (a) Chemical substance...generically as modified magnesium silicate polymer (PMN P-98-604) is subject to...

2010-07-01

406

21 CFR 182.2122 - Aluminum calcium silicate.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 false Aluminum calcium silicate. 182.2122 Section 182.2122...Anticaking Agents § 182.2122 Aluminum calcium silicate. (a) Product. Aluminum calcium silicate. (b) Tolerance. 2...

2013-04-01

407

21 CFR 582.2122 - Aluminum calcium silicate.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 false Aluminum calcium silicate. 582.2122 Section 582.2122...Anticaking Agents § 582.2122 Aluminum calcium silicate. (a) Product. Aluminum calcium silicate. (b) Tolerance. 2...

2013-04-01

408

GPU Computing in Space Weather Modeling  

NASA Astrophysics Data System (ADS)

Space weather refers to conditions on the Sun and in the solar wind, magnetosphere, ionosphere, and thermosphere that can influence the performance and reliability of space-borne and ground-based technological systems and that affect human life or health. Space weather has two focal points: scientific research and applications. In order to make the real- or faster than real-time numerical prediction of adverse space weather events and their influence on the geospace environment, high performance computational models are required. The main objective in this talk is how programmable GPUs can be used in the numerical space weather modeling for the study of solar wind background as a crucial part in the numerical space weather modeling. GPU programming is realized for our Solar-Interplanetary-CESE MHD model (SIP-CESE MHD model) by numerically studying the solar corona/interplanetary solar wind. The global solar wind structures is obtained by the established GPU model with the magnetic field synoptic data as input. Meanwhile, the time-dependent solar surface boundary conditions derived from the method of characteristics and the mass flux limit are incorporated to couple the observation and the 3D MHD model. The simulated evolution of the global structures for two Carrington rotations 2058 and 2062 is compared with solar observations and solar wind measurements from spacecrafts near the Earth. The MHD model is also validated by comparison with the standard potential field source surface (PFSS) model. Comparisons show that the MHD results have good overall agreement with coronal and interplanetary structures, including the size and distribution of coronal holes, the position and shape of the streamer belts, and the transition of the solar wind speeds and magnetic field polarities. Our initial tests with available hardware show speedups of roughly 5x compared to traditional software implementation. This work presents a novel application of GPU to the space weather study.

Feng, X.; Zhong, D.; Xiang, C.

2012-12-01

409

Peralkaline Silicic Volcanic Rocks in Northwestern Nevada  

Microsoft Academic Search

Late Tertiary silicic ashflow tuffs and lavas peralkaline in chemical character (atomic Na + K greater than Al), mainly comendites, occur over wide areas in northwestern Nevada and appear to be widespread in southeastern Oregon. Such peralkaline rocks-which are not uncommon in the western United States-and other chemically unusual silicic rocks are found near the margins rather than toward the

Donald C. Noble; David W. Chipman; David L. Giles

1968-01-01

410

The geopolymerisation of alumino-silicate minerals  

Microsoft Academic Search

Geopolymers are similar to zeolites in chemical composition, but they reveal an amorphous microstructure. They form by the co-polymerisation of individual alumino and silicate species, which originate from the dissolution of silicon and aluminium containing source materials at a high pH in the presence of soluble alkali metal silicates. It has been shown before that geopolymerisation can transform a wide

Hua Xu; J. S. J. Van Deventer

2000-01-01

411

The speciation of water in silicate melts  

Microsoft Academic Search

Previous models of water solubility in silicate melts generally assume essentially complete reaction of water molecules to hydroxyl groups. In this paper a new model is proposed that is based on the hypothesis that the observed concentrations of molecular water and hydroxyl groups in hydrous silicate glasses reflect those of the melts from which they were quenched. The new model

Edward Stolper

1982-01-01

412

Federal Plan for Weather Radars.  

National Technical Information Service (NTIS)

The plan for weather radars describes the use of national weather radar resources in providing warnings and forecasts of severe weather for all walks of life within the U.S. Information is given on disaster warnings, general weather forecasting special De...

1973-01-01

413

Social Aspects of Weather Modification  

Microsoft Academic Search

A description of the social context and citizen response to three weather modification projects provides an introduction to the discussion of a variety of social and economic issues related to planned weather modification. Various interest groups have markedly different perspectives on weather modification. Most persons subject to the consequences of weather modification have no opportunity to participate in the associated

J. Eugene Haas

1973-01-01

414

Micro Weather Stations for Mars  

NASA Technical Reports Server (NTRS)

A global network of weather stations will be needed to characterize the near-surface environment on Mars. Here, we review the scientific and measurement objectives of this network. We also show how these objectives can be met within the cost-constrained Mars Surveyor Program by augmenting the Mars Pathfinder-derived landers with large numbers of very small (less than 5 liter), low-mass (less than 5 kg), low-power, low-cost Mini-meteorological stations. Each station would include instruments for measuring atmospheric. pressures, temperatures, wind velocities, humidity, and airborne dust abundance. They would also include a data handling, telemetry, power, atmospheric entry, and deployment systems in a rugged package capable of direct entry and a high-impact landing. In this paper, we describe these systems and summarize the data-taking strategies and data volumes needed to achieve the surface meteorology objectives for Mars.

Crisp, David; Kaiser, William J.; VanZandt, Thomas R.; Hoenk, Michael E.; Tillman, James E.

1995-01-01

415

The space-weather enterprise: past, present, and future  

NASA Astrophysics Data System (ADS)

Space-weather impacts society in diverse ways. Societies' responses have been correspondingly diverse. Taken together these responses constitute a space weather ``enterprise'', which has developed over time and continues to develop. Technological systems that space-weather affects have grown from isolated telegraph systems in the 1840s to ocean and continent-spanning cable communications systems, from a generator electrifying a few city blocks in the 1880s to continent-spanning networks of high-tension lines, from wireless telegraphy in the 1890s to globe-spanning communication by radio and satellites. To have a name for the global totality of technological systems that are vulnerable to space weather, I suggest calling it the cyberelectrosphere. When the cyberelectrosphere was young, scientists who study space weather, engineers who design systems that space weather affects, and operators of such systems - the personnel behind the space-weather enterprise - were relatively isolated. The space-weather enterprise was correspondingly incoherent. Now that the cyberelectrosphere has become pervasive and indispensable to most segments of society, the space weather enterprise has become systematic and coherent. At present it has achieved considerable momentum, but it has barely begun to realize the level of effectiveness to which it can aspire, as evidenced by achievements of a corresponding but more mature enterprise in meteorology, a field which provides useful lessons. The space-weather enterprise will enter a new phase after it matures roughly to where the tropospheric weather enterprise is now. Then it will become indispensable for humankind's further global networking through technology and for humankind's further utilization of and expansion into space.

Siscoe, G.

2000-09-01

416

Utilization of Live Localized Weather Information for Sustainable Agriculture  

NASA Astrophysics Data System (ADS)

Authors: Jim Anderson VP, Global Network and Business Development WeatherBug® Professional Jeremy Usher Managing Director, Europe WeatherBug® Professional Localized, real-time weather information is vital for day-to-day agronomic management of all crops. The challenge for agriculture is twofold in that local and timely weather data is not often available for producers and farmers, and it is not integrated into decision-support tools they require. Many of the traditional sources of weather information are not sufficient for agricultural applications because of the long distances between weather stations, meaning the data is not always applicable for on-farm decision making processes. The second constraint with traditional weather information is the timeliness of the data. Most delivery systems are designed on a one-hour time step, whereas many decisions in agriculture are based on minute-by-minute weather conditions. This is especially true for decisions surrounding chemical and fertilizer application and frost events. This presentation will outline how the creation of an agricultural mesonet (weather network) can enable producers and farmers with live, local weather information from weather stations installed in farm/field locations. The live weather information collected from each weather station is integrated into a web-enabled decision support tool, supporting numerous on-farm agronomic activities such as pest management, or dealing with heavy rainfall and frost events. Agronomic models can be used to assess the potential of disease pressure, enhance the farmer's abilities to time pesticide applications, or assess conditions contributing to yield and quality fluctuations. Farmers and industry stakeholders may also view quality-assured historical weather variables at any location. This serves as a record-management tool for viewing previously uncharted agronomic weather events in graph or table form. This set of weather tools is unique and provides a significant enhancement to the agronomic decision-support process. Direct benefits to growers can take the form of increased yield and grade potential, as well as savings in money and time. Pest management strategies become more efficient due to timely and localized disease and pest modelling, and increased efficacy of pest and weed control. Examples from the Canadian Wheat Board (CWB) WeatherFarm weather network will be utilized to illustrate the processes, decision tools and benefits to producers and farmers.

Anderson, J.; Usher, J.

2010-09-01

417

Toxic elements in silicate cements.  

PubMed

Six brands of silicate cements have been characterized by means of optical emission spectrography with respect to the contents of elements in minor or trace quantities in a search for presence of possible toxic elements. Beryllium was observed in two powders at levels of 1.3 and 1.6% Cadmium was found in two powders at levels of 0.02 and 0.03%. Lead was measured in three powders at levels of 0.001-0.003%. Bismuth, boron, copper, gallium, iron, manganese, titanium, tin and zirconium were found in various brands in either powder or liquid at levels of 0.001-0.1%. Upper limits of the amounts of the various elements that might be transferred to the gastrointestinal tract after dissolution of the cement matrix in the oral cavity have been calculated. PMID:296570

Brune, D

1979-12-01

418

Mesoporous Silicate Materials in Sensing  

PubMed Central

Mesoporous silicas, especially those exhibiting ordered pore systems and uniform pore diameters, have shown great potential for sensing applications in recent years. Morphological control grants them versatility in the method of deployment whether as bulk powders, monoliths, thin films, or embedded in coatings. High surface areas and pore sizes greater than 2 nm make them effective as adsorbent coatings for humidity sensors. The pore networks also provide the potential for immobilization of enzymes within the materials. Functionalization of materials by silane grafting or through co-condensation of silicate precursors can be used to provide mesoporous materials with a variety of fluorescent probes as well as surface properties that aid in selective detection of specific analytes. This review will illustrate how mesoporous silicas have been applied to sensing changes in relative humidity, changes in pH, metal cations, toxic industrial compounds, volatile organic compounds, small molecules and ions, nitroenergetic compounds, and biologically relevant molecules.

Melde, Brian J.; Johnson, Brandy J.; Charles, Paul T.

2008-01-01

419

Sunlight and the Earth - Climate and Weather  

NSDL National Science Digital Library

These web pages trace the processes involved in the sun's impact on weather. This is an exploration of the importance of radiation and reflection of light, both visible and infra-red, and the greenhouse effect. Convection and the role of water vapor are also considered. Global-scale air flows are described, explaining why wind in the continental US usually blows from the west, while near the equator it comes from the east.

Stern, David

2004-05-19

420

Global chemical erosion over the last 250 my: Variations due to changes in paleogeography, paleoclimate, and paleogeology  

SciTech Connect

The authors utilize predictions of runoff from two series of GENESIS (version 1.02) climate model experiments to calculate chemical erosion rates for 12 time slices that span the Mesozoic and Cenozoic. A set of control experiments where geography is altered according to published paleogeographic reconstructions and atmospheric pCO{sub 2} is held fixed at the present-day value was designed to elucidate climate sensitivity to geography alone. A second series of experiments, where the (elevated) atmospheric CO{sub 2} level for each time slice was adapted from Berner (1991), was executed to determine the additional climate sensitivity to this parameter. By holding other climate forcing factors (for example, vegetation) constant throughout the sequence of experiments the authors evaluate the effects of systematic/coherent paleogeographic changes on runoff and temperature, and thus on global rates of chemical weathering. By using empirical relationships between runoff and bicarbonate fluxes for different rock types and maps of paleogeology they calculate global bicarbonate fluxes, taking into account spatial variations in lithology and hydrology. They find that spatial variations in lithology account for little variation in the total or silicate chemical erosion rates. Calculations suggest a weaker-than-expected CO{sub 2}-climate weathering feedback. The reasonable atmospheric pCO{sub 2} variations specified for the climate-model simulations do not lead to climatic effects that support large changes in the chemical erosion rate, compared to those generated by changing paleogeography. In general, however, they find that silicate weathering rates are similar to outgassing rates of volcanic and methamorphic CO{sub 2}.

Gibbs, M.T.; Bluth, G.J.S.; Fawcett, P.J.; Kump, L.R.

1999-07-01

421

2011 Space Weather Workshop to Be Held in April  

NASA Astrophysics Data System (ADS)

The annual Space Weather Workshop will be held in Boulder, Colo., 26-29 April 2011. The workshop will bring customers, forecasters, commercial service providers, researchers, and government agencies together in a lively dialogue about space weather. The workshop will include 4 days of plenary sessions on a variety of topics, with poster sessions focusing on the Sun, interplanetary space, the magnetosphere, and the ionosphere. The conference will address the remarkably diverse impacts of space weather on today's technology. Highlights on this year's agenda will include presentations on space weather impacts on the Global Positioning System (GPS), the Solar Terrestrial Relations Observatory's (STEREO) mission milestone of a 360° view of the Sun, the latest from NASA's Solar Dynamics Observatory (SDO), and space weather impacts on emergency response by the Federal Emergency Management Agency (FEMA). Additionally, the vulnerabilities of satellites and the power grid to space weather will be addressed. Additional highlights will include the Commercial Space Weather Interest Group's (CSWIG) roundtable session and a presentation from the Office of the Federal Coordinator for Meteorology (OFCM). The CSWIG roundtable session on the growth of the space weather enterprise will feature distinguished panelists. As always, lively interaction between the audience and the panel is anticipated. The OFCM will present the National Space Weather Program's new strategic plan.

Peltzer, Thomas

2011-04-01

422

Rates of oxidative weathering on the surface of Mars  

NASA Technical Reports Server (NTRS)

Implicit in the mnemonic 'MSATT' (Mars surface and atmosphere through time) is that rates of surface processes on Mars through time should be investigated, including studies of the kinetics and mechanism of oxidative weathering reactions occurring in the Martian regolith. Such measurements are described. Two major elements analyzed in the Viking Lander XRF experiment that are most vulnerable to atmospheric oxidatio