Science.gov

Sample records for surface weather observations

  1. Atmospheric attenuation calibrations of surface weather observations

    NASA Technical Reports Server (NTRS)

    Sanii, Babak

    2001-01-01

    A correlation between near-IR atmospheric attenuation measurements made by the Atmospheric Visibility Monitor (AVM) at the Table Mountain Facility and airport surface weather observations at Edwards Air Force Base has been performed. High correlations (over 0.93) exist between the simultaneous Edwards observed sky cover and the average AVM measured attenuations over the course of the 10 months analyzed. The statistical relationship between the data-sets allows the determination of coarse attenuation statistics from the surface observations, suggesting that such statistics may be extrapolated from any surface weather observation site, Furthermore, a superior technique for converting AVM images to attenuation values by way of MODTRAN predictions has been demonstrated.

  2. Asian Dust Weather Categorization with Satellite and Surface Observations

    NASA Technical Reports Server (NTRS)

    Lin, Tang-Huang; Hsu, N. Christina; Tsay, Si-Chee; Huang, Shih-Jen

    2011-01-01

    This study categorizes various dust weather types by means of satellite remote sensing over central Asia. Airborne dust particles can be identified by satellite remote sensing because of the different optical properties exhibited by coarse and fine particles (i.e. varying particle sizes). If a correlation can be established between the retrieved aerosol optical properties and surface visibility, the intensity of dust weather can be more effectively and consistently discerned using satellite rather than surface observations. In this article, datasets consisting of collocated products from Moderate Resolution Imaging Spectroradiometer Aqua and surface measurements are analysed. The results indicate an exponential relationship between the surface visibility and the satellite-retrieved aerosol optical depth, which is subsequently used to categorize the dust weather. The satellite-derived spatial frequency distributions in the dust weather types are consistent with China s weather station reports during 2003, indicating that dust weather classification using satellite data is highly feasible. Although the period during the springtime from 2004 to 2007 may be not sufficient for statistical significance, our results reveal an increasing tendency in both intensity and frequency of dust weather over central Asia during this time period.

  3. Verification of National Weather Service spot forecasts using surface observations

    NASA Astrophysics Data System (ADS)

    Lammers, Matthew Robert

    Software has been developed to evaluate National Weather Service spot forecasts issued to support prescribed burns and early-stage wildfires. Fire management officials request spot forecasts from National Weather Service Weather Forecast Offices to provide detailed guidance as to atmospheric conditions in the vicinity of planned prescribed burns as well as wildfires that do not have incident meteorologists on site. This open source software with online display capabilities is used to examine an extensive set of spot forecasts of maximum temperature, minimum relative humidity, and maximum wind speed from April 2009 through November 2013 nationwide. The forecast values are compared to the closest available surface observations at stations installed primarily for fire weather and aviation applications. The accuracy of the spot forecasts is compared to those available from the National Digital Forecast Database (NDFD). Spot forecasts for selected prescribed burns and wildfires are used to illustrate issues associated with the verification procedures. Cumulative statistics for National Weather Service County Warning Areas and for the nation are presented. Basic error and accuracy metrics for all available spot forecasts and the entire nation indicate that the skill of the spot forecasts is higher than that available from the NDFD, with the greatest improvement for maximum temperature and the least improvement for maximum wind speed.

  4. Observational study of atmospheric surface layer and coastal weather in northern Qatar

    NASA Astrophysics Data System (ADS)

    Samanta, Dhrubajyoti; Sadr, Reza

    2016-04-01

    Atmospheric surface layer is the interaction medium between atmosphere and Earth's surface. Better understanding of its turbulence nature is essential in characterizing the local weather, climate variability and modeling of turbulent exchange processes. The importance of Middle East region, with its unique geographical, economical and weather condition is well recognized. However, high quality micrometeorological observational studies are rare in this region. Here we show experimental results from micrometeorological observations from an experimental site in the coastal region of Qatar during August-December 2015. Measurements of winds are obtained from three sonic anemometers installed on a 9 m tower placed at Al Ghariyah beach in northern Qatar (26.08 °N, 51.36 °E). Different surface layer characteristics is analyzed and compared with earlier studies in equivalent weather conditions. Monthly statistics of wind speed, wind direction, temperature, humidity and heat index are made from concurrent observations from sonic anemometer and weather station to explore variations with surface layer characteristics. The results also highlights potential impact of sea breeze circulation on local weather and atmospheric turbulence. The observed daily maximum temperature and heat index during morning period may be related to sea breeze circulations. Along with the operational micrometeorological observation system, a camera system and ultrasonic wave measurement system are installed recently in the site to study coastline development and nearshore wave dynamics. Overall, the complete observational set up is going to provide new insights about nearshore wind dynamics and wind-wave interaction in Qatar.

  5. On Observing the Weather

    ERIC Educational Resources Information Center

    Crane, Peter

    2004-01-01

    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…

  6. Evaluation of weather forecasts and observations using surface analyses over the western United States

    NASA Astrophysics Data System (ADS)

    Myrick, David Thomas

    Surface analyses created by the Advanced Regional Prediction System Data Assimilation System (ADAS) valid during the 2003/04 winter season (18 November 2003-7 March 2004) are used to verify National Weather Service (NWS) gridded temperature forecasts and evaluate the sensitivity of objective analyses to Remote Automated Weather Station (RAWS) temperature and wind speed observations. The ADAS analyses are based on Rapid Update Cycle analyses that are adjusted by over 3000 surface observations from MesoWest. Accuracy and skill of the NWS gridded forecasts are determined by point verification against the MesoWest observations and gridded verification against the RUC and ADAS analyses. The impact of RAWS observations on the ADAS analyses is assessed by three metrics (accuracy, sensitivity, and areal influence) that rely on results from a series of data withholding experiments. For the West as a whole, the NWS gridded temperature forecasts issued at 0000 UTC during the 2003/04 winter season exhibit skill at lead times of 12, 24, 36, and 48 h on the basis of several verification approaches. The root-mean-square errors (rmse) of the NWS gridded temperature forecasts are estimated to be on the order of 3°C at lead times shorter than 48 h and greater than 4°C at lead times longer than 120 h. Incremental improvements in forecast accuracy as a result of forecaster adjustments to the 0000 UTC temperature grids from 144- to 24-h lead times are estimated to be on the order of 13%. Random withholding of observations from the ADAS analyses provides a baseline estimate of the analysis quality. Relative to this baseline, removing the RAWS observations degrades ADAS temperature (wind speed) analyses by an additional 0.5°C (0.9 m s-1) when evaluated in terms of rmse over the entire season. RAWS temperature observations adjust the RUC background the most during the early morning hours and during winter season cold pool events in the western United States while wind speed

  7. Optimizing weather radar observations using an adaptive multiquadric surface fitting algorithm

    NASA Astrophysics Data System (ADS)

    Martens, Brecht; Cabus, Pieter; De Jongh, Inge; Verhoest, Niko

    2013-04-01

    Real time forecasting of river flow is an essential tool in operational water management. Such real time modelling systems require well calibrated models which can make use of spatially distributed rainfall observations. Weather radars provide spatial data, however, since radar measurements are sensitive to a large range of error sources, often a discrepancy between radar observations and ground-based measurements, which are mostly considered as ground truth, can be observed. Through merging ground observations with the radar product, often referred to as data merging, one may force the radar observations to better correspond to the ground-based measurements, without losing the spatial information. In this paper, radar images and ground-based measurements of rainfall are merged based on interpolated gauge-adjustment factors (Moore et al., 1998; Cole and Moore, 2008) or scaling factors. Using the following equation, scaling factors (C(xα)) are calculated at each position xα where a gauge measurement (Ig(xα)) is available: Ig(xα)+-? C (xα) = Ir(xα)+ ? (1) where Ir(xα) is the radar-based observation in the pixel overlapping the rain gauge and ? is a constant making sure the scaling factor can be calculated when Ir(xα) is zero. These scaling factors are interpolated on the radar grid, resulting in a unique scaling factor for each pixel. Multiquadric surface fitting is used as an interpolation algorithm (Hardy, 1971): C*(x0) = aTv + a0 (2) where C*(x0) is the prediction at location x0, the vector a (Nx1, with N the number of ground-based measurements used) and the constant a0 parameters describing the surface and v an Nx1 vector containing the (Euclidian) distance between each point xα used in the interpolation and the point x0. The parameters describing the surface are derived by forcing the surface to be an exact interpolator and impose that the sum of the parameters in a should be zero. However, often, the surface is allowed to pass near the observations (i

  8. Initializing Weather Research and Forecasting (WRF) model with land surface conditions from the Terrestrial Observation and PredictionSystem (TOPS)

    NASA Astrophysics Data System (ADS)

    Hashimoto, H.; Wang, W.; Melton, F.; Milesi, C.; Michaellis, A.; Nemani, R.

    2008-12-01

    Weather forecasting models have been shown to exhibit a strong sensitivity to land surface conditions, particularly soil moisture. However, the lack of robust estimates of soil moisture at appropriate time and space scales has been a persistent problem. Terrestrial Observation and Prediction System (TOPS) integrates surface weather observations and satellite data with ecosystem simulation models to produce spatially and temporally consistent nowcasts and forecasts of land surface conditions such as soil moisture, evapotranspiration, vegetation stress and photosynthesis. To extend TOPS capabilities beyond estimating ecosystem rocesses, we integrated TOPS with Weather Research Forecasting (WRF) model to evaluate the utility of TOPS-derived surface conditions such as soil moisture in weather forecasting. TOPS land surface schemes are based on a well-calibrated ecosystem model, Biome-BGC, for simulating water and carbon budgets. One of the advantages of TOPS is its flexibility, which enables it to ingest data from a variety of sensors and surface networks, and thus we can provide the surface conditions to users from historical to near real-time, and for spatial scales ranging from 1km and up. We ran the TOPS-WRF system over California for several days during 2007. The results show TOPS-WRF simulations are consistently better than default WRF simulations, particularly over the dry season when spatial variability in soil moisture becomes a significant factor in influencing local energy balance.

  9. F. E. Warren AFB, Cheyenne, Wyoming. Revised uniform summary of surface weather observations (RUSSWO). Parts A-F. Final report

    SciTech Connect

    Not Available

    1980-05-01

    This report is a six-part statistical summary of surface weather observations for F E Warren AFB, Cheyenne, Wyoming. It contains the following parts: (A) Weather Conditions; Atmospheric Phenomena; (B) Precipitation, Snowfall and Snow Depth (daily amounts and extreme values); (C) Surface winds; (D) Ceiling Versus Visibility; Sky Cover; (E) Psychrometric Summaries (daily maximum and minimum temperatures, extreme maximum and minimum temperatures, psychrometric summary of wet-bulb temperature depression versus dry-bulb temperature, means and standard deviations of dry-bulb, wet-bulb and dew-point temperatures and relative humidity); and (F) Pressure Summary (means, standard, deviations, and observation counts of station pressure and sea-level pressure). Data in this report are presented in tabular form, in most cases in percentage frequency of occurrence or cumulative percentage frequency of occurrence tables.

  10. Weather induced effects on extensive air showers observed with the surface detector of the Pierre Auger Observatory

    NASA Astrophysics Data System (ADS)

    Bleve, Carla

    The rate of events measured with the surface detector (SD) of the Pierre Auger Observatory is found to be modulated by the weather conditions. This effect, observed in different ranges of S(1000), the signal measured at 1000 m from the shower core, is due to the increasing amount of matter traversed by a shower as the ground pressure increases and to the inverse proportionality of the Moliere radius to the air density near ground. The latter effect results in a modulation of the lateral spread of the shower with T and P. Air- shower simulations with different realistic profiles of the atmosphere support this interpretation of the observed effects.

  11. All-weather estimates of the land surface skin temperatures from combined analyses of microwave and infrared satellite observations

    NASA Astrophysics Data System (ADS)

    Jimenez, C.; Aires, F.; Prigent, C.; Catherinot, J.; Rossow, W. B.

    2011-12-01

    The surface skin temperature (Ts) is a key parameter at the land-atmosphere interface. Global datasets of Ts are traditionally estimated from satellite infrared radiance observations, under clear sky conditions. First, the inter-comparison of different IR land surface temperature satellite datasets (ISCCP, MODIS, and AIRS) is presented, along with an evaluation with in situ measurements at selected stations archived during CEOP (Coordinated Enhanced Observing Period). The objective is to assess the accuracy of the Ts estimates, and to evidence the major error sources in the retrieval. Results show that the major sources of differences between the different satellite products come from instrument calibration differences, especially for high Ts, followed by the impact of the water vapor treatment in the algorithm, and the differences in surface emissivities. The main limitation of satellite infrared measurements of Ts is their inability to penetrate clouds, limiting them to clear conditions. Microwave wavelengths, being much less affected by clouds than the infrared, are an attractive alternative in cloudy regions as they can be used to derive an all-sky skin Ts product. A neural network inversion scheme has been developed to retrieve surface Ts along with atmospheric water vapor, cloud liquid water, and surface emissivities over land from a combined analysis of Special Sensor Microwave /Imager (SSM/I) and International Satellite Cloud Climatology Project (ISCCP) data. In the absence of routine in situ Ts measurements, retrieved all-weather Ts values are first evaluated globally by comparison to the surface air temperature (Tair) measured by the meteorological station network. The Ts-Tair difference from the global comparisons showed all the expected variations with solar flux, soil characteristics, and cloudiness. This evaluation has been recently extended locally at a few sites by using the Ts in-situ measurements from several CEOP stations representing different

  12. Martian surface weathering studies

    NASA Technical Reports Server (NTRS)

    Calvin, M.

    1973-01-01

    The nature of the Martian surface was characterized by means of its reflectance properties. The Mariner 9 photography was used to establish terrain units which were crossed by the Mariner 6 and 7 paths. The IR reflectance measured by the IR spectrometers on these spacecraft was to be used to indicate the nature of the surface within these units. There is an indication of physical size and/or compositional variation between units but too many natural parameters can vary (size, shape, composition, adsorbed phases, reradiation, atmospheric absorbtion, temperature gradients, etc.) to be certain what effect is causing those variations observed. It is suggested that the characterization could be fruitfully pursued by a group which was dedicated to peeling back the layers of minutia affecting IR reflectance.

  13. Weather and climate. [review of satellite observations

    NASA Technical Reports Server (NTRS)

    Atlas, D.

    1981-01-01

    Highlights of recent progress and the directions of future advances in the application of space observations to weather and climate are reviewed. In mesometeorology and severe storms, satellite stereography of cloud topography and temperature profiling from GOES-VAS promise dramatic developments in both nowcasting and prediction. In global weather, the initial results from the year long Global Weather Experiment conclusively demonstrate the enhanced forecast skill emanating from the use of satellite data, especially cloud track winds and temperature profiles. In climate, empirical studies and numerical experiments point to the feasibility of useful climate predictions on monthly and seasonal time scales. They also indicate the kinds of surface boundary conditions to which climate is sensitive and which need to be observed from space.

  14. Space weathering: from laboratory to observations .

    NASA Astrophysics Data System (ADS)

    Brunetto, R.; Orofino, V.; Strazzulla, G.

    An ongoing research program in our laboratories is focusing on the effects of laser ablation and ion irradiation on silicates, meteorites, and ices, as a simulation of space weathering on Solar System minor bodies (asteroids, Trans-Neptunian Objects, etc.). Spectroscopic results show a general reddening and darkening of the various materials in the 0.3-2.7 mu m range. Laboratory data are then compared with observations, through spectral characterization and scattering models, indicating that space weathering is a very efficient process both in the inner and outer Solar System. In particular, we demonstrated that the majority of TNOs and Centaurs can develop an organic crust mantle produced after irradiation of simple C-bearing molecules. Another relevant result is that the exposure to surface space weathering of asteroid 832 Karin, as calculated from our experiments and models, is in agreement with a dynamical time-scale, i.e. the age of the corresponding Karin family.

  15. Asteroid Surface Alteration by Space Weathering Processes

    NASA Astrophysics Data System (ADS)

    Brunetto, R.; Loeffler, M. J.; Nesvorný, D.; Sasaki, S.; Strazzulla, G.

    Micrometeorite bombardment and irradiation by solar wind and cosmic-ray ions cause variations in the optical properties of small solar system bodies surfaces, affecting efforts to draw connections between specific meteorites and asteroid types. These space weathering processes have been widely studied for the Moon and S- and V-type asteroids, and they are currently being investigated for other asteroid types. Here we review the laboratory studies performed by several groups on meteorites and asteroid surface analogs, aimed at simulating space weathering by using ion irradiation and laser ablation. Together with direct evidence of weathering of particles from asteroid Itokawa acquired by the Hayabusa mission, these results have provided a fundamental contribution to the spectral interpretation of asteroid observations, to establish a solid asteroids-meteorites link, and to understand the energetic processes affecting the surfaces of minor bodies. A general scheme for asteroid optical maturation is thus emerging. Slope trends from large surveys and in particular of young asteroid families have confirmed that solar wind is the main source of rapid (104-106 yr) weathering, and that a number of rejuvenating processes (impacts by small meteorites, planetary encounters, regolith shaking, etc.) efficiently counterbalance the fast weathering timescales.

  16. Earth Observation Services Weather Imaging

    NASA Technical Reports Server (NTRS)

    1992-01-01

    Microprocessor-based systems for processing satellite data offer mariners real-time images of weather systems, day and night, of large areas or allow them to zoom in on a few square miles. Systems West markets these commercial image processing systems, which have significantly decreased the cost of satellite weather stations. The company was assisted by the EOCAP program, which provides government co-funding to encourage private investment in, and to broaden the use of, NASA-developed technology for analyzing information about Earth and ocean resources.

  17. Statistics of link blockage due to cloud cover for free-space optical communications using NCDC surface weather observation data

    NASA Technical Reports Server (NTRS)

    Slobin, S. D.; Piazzolla, S.

    2002-01-01

    Cloud opacity is one of the main atmospheric physical phenomena that can jeopardize the successful completion of an optical link between a spacecraft and a ground station. Hence, the site location chosen for a telescope used for optical communications must rely on knowledge of weather and cloud cover statistics for the geographical area where the telescope itself is located.

  18. The Future of Operational Space Weather Observations

    NASA Astrophysics Data System (ADS)

    Berger, T. E.

    2015-12-01

    We review the current state of operational space weather observations, the requirements for new or evolved space weather forecasting capablities, and the relevant sections of the new National strategy for space weather developed by the Space Weather Operations, Research, and Mitigation (SWORM) Task Force chartered by the Office of Science and Technology Policy of the White House. Based on this foundation, we discuss future space missions such as the NOAA space weather mission to the L1 Lagrangian point planned for the 2021 time frame and its synergy with an L5 mission planned for the same period; the space weather capabilities of the upcoming GOES-R mission, as well as GOES-Next possiblities; and the upcoming COSMIC-2 mission for ionospheric observations. We also discuss the needs for ground-based operational networks to supply mission critical and/or backup space weather observations including the NSF GONG solar optical observing network, the USAF SEON solar radio observing network, the USGS real-time magnetometer network, the USCG CORS network of GPS receivers, and the possibility of operationalizing the world-wide network of neutron monitors for real-time alerts of ground-level radiation events.

  19. All-weather land surface skin temperatures from a combined analysis of microwave and infrared satellite observations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The surface skin temperature (Ts) is a key parameter at the land-atmosphere interface. Upwelling longwave radiation directly epends upon Ts. Energy exchanges at the land-surface boundary are largely controlled by the difference between Ts and the surface air temperature, the air and the surface reac...

  20. Satellite observations of weather and climate

    NASA Technical Reports Server (NTRS)

    Kellogg, W. W.

    1974-01-01

    The SEASAT-A program is viewed as a new way to obtain atmospheric observations for weather and climatic studies in the framework of the Global Atmospheric Research Program (GARP). Total information derived from SEASAT-A sensor package provides a synoptic picture of the upper parts of the world's oceans as a prerequisite to the development of dynamic ocean models and combined ocean/atmospheric models for weather forecasting requirements.

  1. A Retrospective, Iterative, Geometry-Based (RIGB) tilt correction method for radiation observed by Automatic Weather Stations on snow-covered surfaces: application to Greenland

    NASA Astrophysics Data System (ADS)

    Wang, W.; Zender, C. S.; van As, D.; Smeets, P. C. J. P.; van den Broeke, M. R.

    2015-11-01

    Surface melt and mass loss of the Greenland Ice Sheet may play crucial roles in global climate change due to their positive feedbacks and large fresh water storage. With few other regular meteorological observations available in this extreme environment, measurements from Automatic Weather Stations (AWS) are the primary data source for studying surface energy budgets, and for validating satellite observations and model simulations. Station tilt, due to irregular surface melt and/or compaction, causes considerable biases in the AWS shortwave radiation measurements. In this study, we identify tilt-induced biases in the climatology of surface shortwave radiative flux and albedo, and retrospectively correct these by iterative application of solar geometric principles. We found, over all the AWS from the Greenland Climate Network (GC-Net), the Kangerlussuaq transect (K-transect) and the Programme for Monitoring of the Greenland Ice Sheet (PROMICE) networks, insolation on fewer than 40 % of clear days peaks within ±0.5 h of solar noon time, with the largest shift exceeding 3 h due to tilt. Hourly absolute biases in the magnitude of surface insolation can reach up to 200 W m-2. We estimate the tilt angles and their directions based on the solar geometric relationship between the simulated insolation at a horizontal surface and the observed insolation by these tilted AWS under clear-sky conditions. Our adjustment reduces the Root Mean Square Error (RMSE) against references from both satellite observation and reanalysis by ~ 20W W m-2, and raises the correlation coefficients with them to above 0.95. Averaged over the whole Greenland Ice Sheet in the melt season, the adjustment in insolation to compensate station tilt is 18 ± 13 W m-2, enough to melt 0.40 ± 0.29 m of snow water equivalent. The adjusted diurnal cycles of albedo are smoother, with consistent semi-smiling patterns. The seasonal cycles and inter-annual variabilities of albedo agree better with previous

  2. A Retrospective, Iterative, Geometry-Based (RIGB) tilt-correction method for radiation observed by automatic weather stations on snow-covered surfaces: application to Greenland

    NASA Astrophysics Data System (ADS)

    Wang, Wenshan; Zender, Charles S.; van As, Dirk; Smeets, Paul C. J. P.; van den Broeke, Michiel R.

    2016-03-01

    Surface melt and mass loss of the Greenland Ice Sheet may play crucial roles in global climate change due to their positive feedbacks and large fresh-water storage. With few other regular meteorological observations available in this extreme environment, measurements from automatic weather stations (AWS) are the primary data source for studying surface energy budgets, and for validating satellite observations and model simulations. Station tilt, due to irregular surface melt, compaction and glacier dynamics, causes considerable biases in the AWS shortwave radiation measurements. In this study, we identify tilt-induced biases in the climatology of surface shortwave radiative flux and albedo, and retrospectively correct these by iterative application of solar geometric principles. We found, over all the AWS from the Greenland Climate Network (GC-Net), the Kangerlussuaq transect (K-transect) and the Programme for Monitoring of the Greenland Ice Sheet (PROMICE) networks, insolation on fewer than 40 % of clear days peaks within ±0.5 h of solar noon time, with the largest shift exceeding 3 h due to tilt. Hourly absolute biases in the magnitude of surface insolation can reach up to 200 W m-2, with respect to the well-understood clear-day insolation. We estimate the tilt angles and their directions based on the solar geometric relationship between the simulated insolation at a horizontal surface and the observed insolation by these tilted AWS under clear-sky conditions. Our adjustment reduces the root mean square error (RMSE) against references from both satellite observation and reanalysis by 16 W m-2 (24 %), and raises the correlation coefficients with them to above 0.95. Averaged over the whole Greenland Ice Sheet in the melt season, the adjustment in insolation to compensate station tilt is ˜ 11 W m-2, enough to melt 0.24 m of snow water equivalent. The adjusted diurnal cycles of albedo are smoother, with consistent semi-smiling patterns. The seasonal

  3. An Iterative, Geometric, Tilt Correction Method for Radiation and Albedo Observed by Automatic Weather Stations on Snow-Covered Surfaces: Application to Greenland

    NASA Astrophysics Data System (ADS)

    Wang, W.; Zender, C. S.; van As, D.; Smeets, P.; van den Broeke, M.

    2015-12-01

    Surface melt and mass loss of Greenland Ice Sheet may play crucial roles in global climate change due to their positive feedbacks and large fresh water storage. With few other regular meteorological observations available in this extreme environment, measurements from Automatic Weather Stations (AWS) are the primary data source for the surface energy budget studies, and for validating satellite observations and model simulations. However, station tilt, due to surface melt and compaction, results in considerable biases in the radiation and thus albedo measurements by AWS. In this study, we identify the tilt-induced biases in the climatology of surface radiative flux and albedo, and then correct them based on geometrical principles. Over all the AWS from the Greenland Climate Network (GC-Net), the Kangerlussuaq transect (K-transect) and the Programme for Monitoring of the Greenland Ice Sheet (PROMICE), only ~15% of clear days have the correct solar noon time, with the largest bias to be 3 hours. Absolute hourly biases in the magnitude of surface insolation can reach up to 200 W/m2, with daily average exceeding 100 W/m2. The biases are larger in the accumulation zone due to the systematic tilt at each station, although variabilities of tilt angles are larger in the ablation zone. Averaged over the whole Greenland Ice Sheet in the melting season, the absolute bias in insolation is ~23 W/m2, enough to melt 0.51 m snow water equivalent. We estimate the tilt angles and their directions by comparing the simulated insolation at a horizontal surface with the observed insolation by these tilted AWS under clear-sky conditions. Our correction reduces the RMSE against satellite measurements and reanalysis by ~30 W/m2 relative to the uncorrected data, with correlation coefficients over 0.95 for both references. The corrected diurnal changes of albedo are more smooth, with consistent semi-smiling patterns (see Fig. 1). The seasonal cycles and annual variabilities of albedo are in

  4. Observational Data Analysis and Numerical Model Assessment of the Seafloor Interaction and Mobility of Sand and Weathered Oil Agglomerates (Surface Residual Balls) in the Surf Zone

    NASA Astrophysics Data System (ADS)

    Dalyander, S.; Long, J.; Plant, N. G.; Penko, A.; Calantoni, J.; Thompson, D.; Mclaughlin, M. K.

    2014-12-01

    When weathered oil is transported ashore, such as during the Deepwater Horizon oil spill, it can mix with suspended sediment in the surf zone to create heavier-than-water sand and oil agglomerates in the form of mats several centimeters thick and tens of meters long. Broken off pieces of these mats and smaller agglomerates formed in situ (called Surface Residual Balls, SRBs) can cause beach re-oiling months to years after the initial spill. The physical dynamics of these SRBs in the nearshore, where they are larger (cm-scale) and less dense than natural sediment, are poorly understood. In the current study, SRB mobility and seafloor interaction is investigated through a combination of laboratory and field experiments with pseudo-SRBs developed to be physically stable proxies for genuine agglomerates. Formulations for mobility prediction based on comparing estimated shear stress to the critical Shields and modified Shields parameters developed for mixed sediment beds are assessed against observations. Processes such as burial, exhumation, and interaction with bedforms (e.g., migrating ripples) are also explored. The observations suggest that incipient motion estimates based on a modified Shields parameter have some skill in predicting SRB movement, but that other forcing mechanisms such as pressure gradients may be important under some conditions. Additionally, burial and exhumation due to the relatively high mobility of sand grains are confirmed as key processes controlling SRB dynamics in the surf zone. This work has broad implications for understanding surf zone sediment transport at the short timescale associated with mobilizing sand grains and SRBs as well as at the longer timescales associated with net transport patterns, sediment budgets, and bed elevation changes.

  5. Space weathering of asteroids: Lessons from Itokawa for future observations

    NASA Astrophysics Data System (ADS)

    Sasaki, Sho; HIroi, Takahiro

    2016-07-01

    Introduction Space weathering of surface silicate minerals is the main process that should control the change of brightness and color of airless silicate bodies such and the Moon, Mercury and asteroids. Spectra of S-type asteroids exhibit more overall depletion and reddening, and more weakening of absorption bands than spectra of ordinary chondrites. These spectral mismatches are explained by the space weathering, where the primary proven mechanism of such spectral change is production of nanophase metallic iron particles (npFe0) 1), which were confirmed in the amorphous rim of lunar soil grains 2,3). Vapor-deposition through at high-velocity dust particle impacts as well as implantation of intensive solar wind ions would be responsible for producing the space weathering rims bearing nano-iron particles (npFe0). Simulation experiments using nanosecond pulse laser successfully produced vapor-deposition type npFe0 to change optical properties 4,5,6). Laser experiments showed that pyroxene would be weathered less than olivine, for pyroxene, pulse laser irradiation produced melt (amorphous) droplets containing npFe0, rather than vapour deposited rim that should provide stronger optical effect trough multiple scattering of incidental light. Itokawa Observed by Remote Sensing In November 2005, Japanese Asteroid Sample Return Mission HAYABUSA spacecraft rendezvoused S-type asteroid (25143) Itokawa. Optically, the surface of Itokawa is divided into brighter (and bluer) areas and darker (and redder) areas 7,8). In rough zones, dark boulder-rich surfaces usually superpose on bright materials. The near-infrared spectrometer (NIRS) confirmed previous disk-integrated results that suggested Itokawa's spectrum closely matched a weakly weathered LL5/6 chondrite 9). Although the surface is covered with rocks and is apparently lack of fine regolith, Itokawa's surface show darkening and reddening by space weathering. Experimental results suggest rocky meteorite fragments can be

  6. Weather observations through oceanic acoustic noise recorded by gliders

    NASA Astrophysics Data System (ADS)

    Cauchy, Pierre; Testor, Pierre; Guinet, Christophe; Gervaise, Cedric; Di Oro, Lucia; Ioana, Cornel; Mortier, Laurent; Bouin, Marie-Noelle; Beguery, Laurent; Klein, Patrice

    2013-04-01

    Offshore estimates of the meteorological parameters are unfortunately spurious when considering in-situ observtions only due to obvious observational limitations while their use would allow to calibrate satellite observations and to have better weather forecasts, if assimilated in numerical weather forecasting systems. The WOTAN (Weather Observations through Acoustic Noise) approach may be used to fill these gaps if coupled to the Global Ocean Observing Sytem which has now a global coverage thanks to many autonomous observing platforms. In this study we show first results from acoustic records collected by gliders deployed in the northwestern Mediterranean Sea in the framework of MOOSE. We show that using 3 descriptors at 5kHz, 8kHz, and 20kHz allows to extract the intensity of the wind and the precipitation when the glider is at depth. This approach based on the method presented by Barry & Nuysten (2004) is compared with meterological data from coastal weather stations and the offshore meteorological buoys from Meteo-France. We also show that there is a vane effect with the tail of the glider while at surface which allows to estimate the direction of the wind every so often. These observations coupled with the in-situ profiles on temperature and salinity profiles can allow to better study air-sea interactions.

  7. Evaluating climate models: Should we use weather or climate observations?

    SciTech Connect

    Oglesby, Robert J; Erickson III, David J

    2009-12-01

    Calling the numerical models that we use for simulations of climate change 'climate models' is a bit of a misnomer. These 'general circulation models' (GCMs, AKA global climate models) and their cousins the 'regional climate models' (RCMs) are actually physically-based weather simulators. That is, these models simulate, either globally or locally, daily weather patterns in response to some change in forcing or boundary condition. These simulated weather patterns are then aggregated into climate statistics, very much as we aggregate observations into 'real climate statistics'. Traditionally, the output of GCMs has been evaluated using climate statistics, as opposed to their ability to simulate realistic daily weather observations. At the coarse global scale this may be a reasonable approach, however, as RCM's downscale to increasingly higher resolutions, the conjunction between weather and climate becomes more problematic. We present results from a series of present-day climate simulations using the WRF ARW for domains that cover North America, much of Latin America, and South Asia. The basic domains are at a 12 km resolution, but several inner domains at 4 km have also been simulated. These include regions of complex topography in Mexico, Colombia, Peru, and Sri Lanka, as well as a region of low topography and fairly homogeneous land surface type (the U.S. Great Plains). Model evaluations are performed using standard climate analyses (e.g., reanalyses; NCDC data) but also using time series of daily station observations. Preliminary results suggest little difference in the assessment of long-term mean quantities, but the variability on seasonal and interannual timescales is better described. Furthermore, the value-added by using daily weather observations as an evaluation tool increases with the model resolution.

  8. Automation of surface observations program

    NASA Technical Reports Server (NTRS)

    Short, Steve E.

    1988-01-01

    At present, surface weather observing methods are still largely manual and labor intensive. Through the nationwide implementation of Automated Surface Observing Systems (ASOS), this situation can be improved. Two ASOS capability levels are planned. The first is a basic-level system which will automatically observe the weather parameters essential for aviation operations and will operate either with or without supplemental contributions by an observer. The second is a more fully automated, stand-alone system which will observe and report the full range of weather parameters and will operate primarily in the unattended mode. Approximately 250 systems are planned by the end of the decade. When deployed, these systems will generate the standard hourly and special long-line transmitted weather observations, as well as provide continuous weather information direct to airport users. Specific ASOS configurations will vary depending upon whether the operation is unattended, minimally attended, or fully attended. The major functions of ASOS are data collection, data processing, product distribution, and system control. The program phases of development, demonstration, production system acquisition, and operational implementation are described.

  9. Widespread Surface Weathering on Early Mars

    NASA Astrophysics Data System (ADS)

    Loizeau, Damien; Carter, John; Mangold, Nicolas; Poulet, François; Rossi, Angelo; Allemand, Pascal; Quantin, Cathy; Bibring, Jean-Pierre

    2014-05-01

    The recent discovery of widespread hydrous clays on Mars indicates that diverse and widespread aqueous environments existed on Mars, from the surface to kilometric depths [1,2]. The study of the past habitability and past climates of the planet requires assessing the importance of sustained surface water vs. subsurface water in its aqueous history. Using remote sensing data, we propose that surface weathering existed on Mars, suggesting that Mars experienced durable episodes of sustained liquid water on its surface. Weathering profiles are identified as vertical sequences of Al-rich clays and Fe/Mg-rich clays in the top tens of meters of the surface, similar to cases of pedogenesis on Earth (e.g. [3,4]). Such localized clay sequences have been reported by other works in 3 regions of Mars [5-8] and a similar origin was also proposed. Their frequency is however likely underestimated due to limitations of orbital investigations and re-surfacing processes. A large survey of the CRISM dataset leaded to a down-selection of ~100 deposits with clear vertical sequences, widely distributed over the southern highlands and grouped in regional clusters [9]. These putative weathering sequences are found either on inter-crater plateaus, on the floor of craters and large basins, or on crater ejectas. We investigated the thickness of the altered sequences, the age of the altered units and the different geological contexts to further understand the weathering process(es). Using few HiRISE DEMs where possible, and CTX DEMs, we find that the thickness of the exposed Al clays is on average of the order of several meters to few tens of meters. The clay sequences reported here are consistent with terrestrial weathering sequences which form under wet climates over geological timescales (>105-107 years). The combined age assessment of the altered unit and the unaltered capping (where present) provides constraints on the age of the weathering itself. All investigated cases point to an

  10. Widespread Surface Weathering on Early Mars

    NASA Astrophysics Data System (ADS)

    Loizeau, D.; Carter, J.; Mangold, N.; Poulet, F.; Rossi, A.; Allemand, P.; Quantin, C.; Bibring, J.

    2013-12-01

    The recent discovery of widespread hydrous clays on Mars indicates that diverse and widespread aqueous environments existed on Mars, from the surface to kilometric depths [1,2]. The study of the past habitability of the planet requires assessing the importance of sustained surface water vs. subsurface water in its aqueous history. Using remote sensing data, we propose that surface weathering existed on Mars, suggesting that Mars experienced durable episodes of sustained liquid water on its surface. Weathering profiles are identified as vertical sequences of Al-rich clays and Fe/Mg-rich clays in the top tens of meters of the surface, similar to cases of pedogenesis on Earth (e.g. [3,4]). Such localized clay sequences have been reported by other works in 3 regions of Mars [5-8] and a similar origin was also proposed. Their frequency is however likely underestimated due to limitations of orbital investigations and re-surfacing processes. A large survey of the CRISM dataset leaded to a down-selection of 104 deposits with clear vertical sequences, widely distributed over the southern highlands and grouped in regional clusters [9]. These putative weathering sequences are found either on inter-crater plateaus, on the floor of craters and large basins, or on crater ejectas. We investigated the thickness of the altered sequences, the age of the altered units and the different geological contexts to further understand the weathering process(es). Using few HiRISE DEMs where possible, and CTX DEMs, we find that the thickness of the exposed Al clays is on average of the order of several meters to few tens of meters. The clay sequences reported here are consistent with terrestrial weathering sequences which form under wet climates over geological timescales (> 105-107 years). The combined age assessment of the altered unit and the unaltered capping (where present) provides constraints on the age of the weathering itself. All investigated cases point to an active weathering

  11. Rates of oxidative weathering on the surface of Mars

    NASA Technical Reports Server (NTRS)

    Burns, Roger G.

    1992-01-01

    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 oxidation are iron and sulfur. Originally, they occurred as Fe(2+)-bearing silicate and sulfide minerals in basaltic rocks on the surface of Mars. However, chemical weathering reactions through time have produced ferric- and sulfate-bearing assemblages now visible in the Martian regolith. Such observations raise several question about: (1) when the oxidative weathering reactions took place on Mars; (2) whether or not the oxidized regolith is a fossilized remnant of past weathering processes; (3) deducting chemical interactions of the ancient Martian atmosphere with its surface from surviving phases; (4) possible weathering reactions still occurring in the frozen regolith; and (5) the kinetics and mechanism of past and present-day oxidative reactions on Mars. These questions may be addressed experimentally by studying reaction rates of dissolution and oxidation of basaltic minerals, and by identifying reaction products forming on the mineral surfaces. Results for the oxidation of pyrrhotite and dissolved ferrous iron are reported.

  12. A gridded multisite weather generator and synchronization to observed weather data

    NASA Astrophysics Data System (ADS)

    Wilks, Daniel S.

    2009-10-01

    Procedures are described for constructing a daily multisite weather generator at a collection of arbitrary (e.g., gridded) locations and for synchronizing the gridded generator to observed weather series at a set of reference stations. The gridded generator is constructed by interpolating conventional single-station weather generator parameters using locally weighted regressions and producing coherent simulations of daily weather from them using spatial correlation functions. When implemented, the synchronization algorithm results in simulated spatial weather fields at the grid points that are consistent with daily weather observations at nearby locations for particular years. The synchronization is achieved by exploiting the latent multivariate Gaussian structure of the spatially distributed weather generator and making use of well-known statistical results that define conditional multivariate Gaussian distributions given known values for a subset of variables from the larger joint distribution. The primary focus is on precipitation, but the nonprecipitation variables in the weather generator are also amenable to gridding and to synchronization with nearby observed weather series. The motivating idea is to allow calibration of spatially distributed hydrological models consistent with the climate of the spatial weather generator, potentially allowing more realistic hydrological simulation, but the procedure may also be useful for interpolation of missing daily weather data.

  13. Space weathering of asteroids: Lessons from Itokawa for future observations

    NASA Astrophysics Data System (ADS)

    Sasaki, Sho; HIroi, Takahiro

    2016-07-01

    Introduction Space weathering of surface silicate minerals is the main process that should control the change of brightness and color of airless silicate bodies such and the Moon, Mercury and asteroids. Spectra of S-type asteroids exhibit more overall depletion and reddening, and more weakening of absorption bands than spectra of ordinary chondrites. These spectral mismatches are explained by the space weathering, where the primary proven mechanism of such spectral change is production of nanophase metallic iron particles (npFe0) 1), which were confirmed in the amorphous rim of lunar soil grains 2,3). Vapor-deposition through at high-velocity dust particle impacts as well as implantation of intensive solar wind ions would be responsible for producing the space weathering rims bearing nano-iron particles (npFe0). Simulation experiments using nanosecond pulse laser successfully produced vapor-deposition type npFe0 to change optical properties 4,5,6). Laser experiments showed that pyroxene would be weathered less than olivine, for pyroxene, pulse laser irradiation produced melt (amorphous) droplets containing npFe0, rather than vapour deposited rim that should provide stronger optical effect trough multiple scattering of incidental light. Itokawa Observed by Remote Sensing In November 2005, Japanese Asteroid Sample Return Mission HAYABUSA spacecraft rendezvoused S-type asteroid (25143) Itokawa. Optically, the surface of Itokawa is divided into brighter (and bluer) areas and darker (and redder) areas 7,8). In rough zones, dark boulder-rich surfaces usually superpose on bright materials. The near-infrared spectrometer (NIRS) confirmed previous disk-integrated results that suggested Itokawa's spectrum closely matched a weakly weathered LL5/6 chondrite 9). Although the surface is covered with rocks and is apparently lack of fine regolith, Itokawa's surface show darkening and reddening by space weathering. Experimental results suggest rocky meteorite fragments can be

  14. FTIR Spectra of Possible End Products of Martian Surface Weathering

    NASA Astrophysics Data System (ADS)

    Maxe, L. P.

    2008-03-01

    Comparative analysis of IR spectra shows that martian weathering can lead to separating destruction of surface rocks. The semi-cosmic martian weathering results in amorphous silica dust and open unique ferry aluminum/ferry silicate martian rocks.

  15. An evaluation of the impact of aerosol particles on weather forecasts from a biomass burning aerosol event over the Midwestern United States: observational-based analysis of surface temperature

    NASA Astrophysics Data System (ADS)

    Zhang, Jianglong; Reid, Jeffrey S.; Christensen, Matthew; Benedetti, Angela

    2016-05-01

    A major continental-scale biomass burning smoke event from 28-30 June 2015, spanning central Canada through the eastern seaboard of the United States, resulted in unforecasted drops in daytime high surface temperatures on the order of 2-5 °C in the upper Midwest. This event, with strong smoke gradients and largely cloud-free conditions, provides a natural laboratory to study how aerosol radiative effects may influence numerical weather prediction (NWP) forecast outcomes. Here, we describe the nature of this smoke event and evaluate the differences in observed near-surface air temperatures between Bismarck (clear) and Grand Forks (overcast smoke), to evaluate to what degree solar radiation forcing from a smoke plume introduces daytime surface cooling, and how this affects model bias in forecasts and analyses. For this event, mid-visible (550 nm) smoke aerosol optical thickness (AOT, τ) reached values above 5. A direct surface cooling efficiency of -1.5 °C per unit AOT (at 550 nm, τ550) was found. A further analysis of European Centre for Medium-Range Weather Forecasts (ECMWF), National Centers for Environmental Prediction (NCEP), United Kingdom Meteorological Office (UKMO) near-surface air temperature forecasts for up to 54 h as a function of Moderate Resolution Imaging Spectroradiometer (MODIS) Dark Target AOT data across more than 400 surface stations, also indicated the presence of the daytime aerosol direct cooling effect, but suggested a smaller aerosol direct surface cooling efficiency with magnitude on the order of -0.25 to -1.0 °C per unit τ550. In addition, using observations from the surface stations, uncertainties in near-surface air temperatures from ECMWF, NCEP, and UKMO model runs are estimated. This study further suggests that significant daily changes in τ550 above 1, at which the smoke-aerosol-induced direct surface cooling effect could be comparable in magnitude with model uncertainties, are rare events on a global scale. Thus, incorporating

  16. A web-based tool that combines satellite and weather station observations to support irrigation scheduling

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Abstract: The Satellite Irrigation Management Support (SIMS) project combines NASA's Terrestrial Observation and Prediction System (TOPS), Landsat and MODIS satellite imagery, and reference evapotranspiration from surface weather station networks to map daily crop irrigation demand in California in ...

  17. Surface Landing Site Weather Analysis for Constellation Program

    NASA Technical Reports Server (NTRS)

    Altino, Karen M.; Burns, K. Lee

    2008-01-01

    Weather information is an important asset for NASA's Constellation Program in developing the next generation space transportation system to fly to the International Space Station, the Moon and, eventually, to Mars. Weather conditions can affect vehicle safety and performance during multiple mission phases ranging from pre-launch ground processing to landing and recovery operations, including all potential abort scenarios. Meteorological analysis is an important contributor, not only to the development and verification of system design requirements but also to mission planning and active ground operations. Of particular interest are the surface atmospheric conditions at both nominal and abort landing sites for the manned Orion capsule. Weather parameters such as wind, rain, and fog all play critical roles in the safe landing of the vehicle and subsequent crew and vehicle recovery. The Marshall Space Flight Center Natural Environments Branch has been tasked by the Constellation Program with defining the natural environments at potential landing zones. Climatological time series of operational surface weather observations are used to calculate probabilities of occurrence of various sets of hypothetical vehicle constraint thresholds, Data are available for numerous geographical locations such that statistical analysis can be performed for single sites as well as multiple-site network configurations. Results provide statistical descriptions of how often certain weather conditions are observed at the site(s) and the percentage that specified criteria thresholds are matched or exceeded. Outputs are tabulated by month and hour of day to show both seasonal and diurnal variation. This paper will describe the methodology used for data collection and quality control, detail the types of analyses performed, and provide a sample of the results that can be obtained,

  18. Surface and internal structures of a space-weathered rim of an Itokawa regolith particle

    NASA Astrophysics Data System (ADS)

    Matsumoto, Toru; Tsuchiyama, Akira; Miyake, Akira; Noguchi, Takaaki; Nakamura, Michihiko; Uesugi, Kentaro; Takeuchi, Akihisa; Suzuki, Yoshio; Nakano, Tsukasa

    2015-09-01

    Surface morphologies of a regolith particle retrieved from Asteroid 25143 Itokawa were observed using field-emission scanning electron microscopy (FE-SEM). The images were compared with the internal structures of the space-weathered rim of the same particle observed by transmission electron and scanning transmission electron microscopies (TEM/STEM) to investigate whether there is a direct link between the surface morphology and internal structure. FE-SEM observation showed that most of the particle surface is covered by convex spots less than 100 nm in size. TEM/STEM observation revealed that this particle has a space-weathered rim composed of partially amorphous structures with nano-Fe particles and vesicles. The vesicles swell the surface and form blisters that correspond to the spotted structures observed by FE-SEM. These observations indicate that a space-weathered rim with blisters can be observed by FE-SEM without using destructive methods. The observation of the space-weathered rim by FE-SEM also enabled us to obtain the distribution of the space-weathered rim on the particle surfaces. The existence of space-weathered rims on the opposing surfaces of the particle shows that most of the surfaces were directly exposed to the space environment by movement on the Itokawa surface. The depths of the blister locations and the chemical composition of the space-weathered rim indicate that the observed space-weathered rim with blisters was formed mainly by solar wind irradiation. The space-weathered rim analyzed in this study is thicker than those of Itokawa particles previously examined, indicating that the rim may has experienced longer solar wind exposure than those previously observed.

  19. MAGDAS/CPMN Observations for Space Weather Study

    NASA Astrophysics Data System (ADS)

    Yumoto, K.

    2004-05-01

    An objective of the STP (nderline{S}olar nderline{T}errestrial nderline{P}hysics) researches is to support human activities in the geospace in the twenty-first century from an aspect of fundamental study. In order to understand the Sun-Earth system and effects to human lives, the international LWS (nderline{L}iving nderline{W}ith nderline{S}tar) and CAWSES (nderline{C}limate nderline{a}nd nderline{W}eather of nderline{S}un-nderline{E}arth nderline{S}ystem) programs start from 2004. The objective of CAWSES-WG 2 & 3 in Japan for the region from the solar surface through the solar wind, the magnetosphere, the ionosphere, and the thermosphere, to the atmosphere is a creation of new physics; (1) couplings of the complex and composite systems and (2) macro-and-micro-scale couplings in the Solar-Terrestrial system. The goals of CAWSES-WG 2 & 3 in Japan are to construct space weather stations (for observations) and modeling stations (for simulation/empirical modeling) during the period (2004-2008) of the international CAWSES program. Japanese STP groups will coordinate a research network to reach these goals for the space weather study. In order to study the complexity in the solar wind-magnetosphere-ionosphere-Earth's surface system, the nderline{S}pace nderline{E}nvironment nderline{R}esearch nderline{C}enter (SERC), Kyushu University, Fukuoka, Japan will carry out coordinated ground-based network observations for space weather studies, in cooperation with about 30 organizations in the world during the international CAWSES period (2004-2008). In the present paper, we will introduce a real-time nderline{MAC}netic nderline{D}ata nderline{A}cquisition nderline{S}ystem of nderline{C}ircumpan nderline{P}acific nderline{M}agnetometer nderline{N}etwork, i.e. MAGDAS/CPMN system in Kyushu University. By using this system, we will conduct the real-time monitoring and modeling of (1) the global 3-dimensional current system and (2) the plasma density variations for space weather

  20. Observing Weather in Venus's Lower Atmosphere

    NASA Astrophysics Data System (ADS)

    Young, E. F.; Bullock, M. A.; Chanover, N. J.; Lemmon, M. T.

    2003-05-01

    The rotation rate of Venus's sulfuric acid clouds is roughly 60 times greater than that of the solid surface, a phenomenon which is only partially understood. To help learn more about the details of the cloud motions, we observed Venus on three occasions near the past two inferior conjunctions at 2.3 microns, a window which transmits thermal radiation emanating from the lower scale heights of the atmosphere. Clouds block the thermal radiation in this wavelength band and show up as silhouettes on Venus's night side. We tracked atmospheric features to estimate their rates and directions. Several previous investigators have used 2.3 micron imaging to track Venus's clouds (e.g., Carlson et al. 1991, Crisp et al. 1991, Chanover et al. 1998). We compare our results to these previous investigations and to a solid-body rotator. We find no clear trend relating rotation rate to latitude. Instead, we often see local features with different rotation rates and different meridional directions from their neighbors within a latitudinal zone. These motions suggest that we are seeing snapshots of eddies in the mid-latitudes. Thick cloud cover is nearly always present at the equatorial latitudes and at both poles. The intermediate latitudes show thin cloud cover which is often broken into several narrow latitudinal ``zones,'' although these zones are certainly unlike belts and zones seen on Jupiter and Saturn, if only because (a) they are ephemeral on timescales of days and (b) they often have orientations that are up to 15 degrees away from the horizontal. As Crisp et al. (1991) suggest, these clearer regions could be the result of downwelling, possibly a manifestation of Hadley cells in the lower cloud deck. In approximately ten percent of our images we see turbulent-looking edges of the cloudy equatorial region, suggesting significant shear between adjacent latitudinal zones. Mark Bullock acknowledges support from NASA's Planetary Atmospheres and NSF's Planetary Astronomy programs

  1. Evidence of Space Weathering Processes Across the Surface of Vesta

    NASA Astrophysics Data System (ADS)

    Pieters, C. M.; Blewett, D. T.; Gaffey, M.; Mittlefehldt, D. W.; De sanctis, M.; Reddy, V.; Coradini, A.; Nathues, A.; Denevi, B. W.; Li, J.; McCord, T. B.; Marchi, S.; Palmer, E. E.; Sunshine, J. M.; Filacchione, G.; Ammannito, E.; Raymond, C. A.; Russell, C. T.

    2011-12-01

    As NASA's Dawn spacecraft explores the surface of Vesta, it has become abundantly clear that Vesta is like no other planetary body visited to date. Dawn is collecting global data at increasingly higher spatial resolution during its one-year orbital mission. The bulk properties of Vesta have previously been linked to the HED meteorites through remote mineral characterization of its surface from Earth-based spectroscopy. A principal puzzle has been why Vesta exhibits relatively unweathered diagnostic optical features compared to other large asteroids. Is this due to the composition of this proto-planet or the space environment at Vesta? Alteration or weathering of materials in space normally develops as the products of several processes accumulate on the surface or in an evolving particulate regolith, transforming the bedrock into fragmental material with properties that may be measurably different from the original. Data from Dawn reveal that the regolith of Vesta is exceptionally diverse. Regional surface units are observed that have not been erased by weathering with time. Several morphologically-fresh craters have excavated bright, mafic-rich materials and exhibit bright ray systems. Some of the larger craters have surrounding subdued regions (often asymmetric) that are lower in albedo and relatively red-sloped in the visible while exhibiting weaker mafic signatures. Several other prominent craters have rim exposures containing very dark material and/or display a system of prominent dark rays. Most, but not all, dark areas associated with craters exhibit significantly lower spectral contrast, suggesting that either a Vesta lithology with an opaque component has been exposed locally or that the surface has been contaminated by a relatively dark impactor. Similarly, most, but not all, bright areas associated with craters exhibit enhanced mafic signatures compared to surroundings. On a regional scale, the large south polar structure and surrounding terrain exhibit

  2. Evidence of Space Weathering Processes Across the Surface of Vesta

    NASA Technical Reports Server (NTRS)

    Pieters, Carle M.; Blewett, David T.; Gaffey, Michael; Mittlefehldt, David W.; CristinaDeSanctis, Maria; Reddy, Vishnu; Coradini, Angioletta; Nathues, Andreas; Denevi, Brett W.; Li, Jian-Yang; McCord, Thomas B.; Marchi, Simone; Palmer, Eric E.; Sunshine, Jessica M.; Filacchione, Gianrico; Ammannito, Eleonora; Raymond, Carol A.; Russell, Christopher T.

    2011-01-01

    As NASA s Dawn spacecraft explores the surface of Vesta, it has become abundantly clear that Vesta is like no other planetary body visited to date. Dawn is collecting global data at increasingly higher spatial resolution during its one-year orbital mission. The bulk properties of Vesta have previously been linked to the HED meteorites through remote mineral characterization of its surface from Earth-based spectroscopy. A principal puzzle has been why Vesta exhibits relatively unweathered diagnostic optical features compared to other large asteroids. Is this due to the composition of this proto-planet or the space environment at Vesta? Alteration or weathering of materials in space normally develops as the products of several processes accumulate on the surface or in an evolving particulate regolith, transforming the bedrock into fragmental material with properties that may be measurably different from the original. Data from Dawn reveal that the regolith of Vesta is exceptionally diverse. Regional surface units are observed that have not been erased by weathering with time. Several morphologically-fresh craters have excavated bright, mafic-rich materials and exhibit bright ray systems. Some of the larger craters have surrounding subdued regions (often asymmetric) that are lower in albedo and relatively red-sloped in the visible while exhibiting weaker mafic signatures. Several other prominent craters have rim exposures containing very dark material and/or display a system of prominent dark rays. Most, but not all, dark areas associated with craters exhibit significantly lower spectral contrast, suggesting that either a Vesta lithology with an opaque component has been exposed locally or that the surface has been contaminated by a relatively dark impactor. Similarly, most, but not all, bright areas associated with craters exhibit enhanced mafic signatures compared to surroundings. On a regional scale, the large south polar structure and surrounding terrain exhibit

  3. Measuring stone weathering in cities: Surface reduction on marble monuments

    SciTech Connect

    Dragovich, D. )

    1987-01-01

    The purpose of this study was to establish whether measurements of stone weathering recorded by different observers could be aggregated into a simple data base for evaluating pollution effects on calcareous building stone. Apparent differences in recorded weathering rates on marble tombstones were here found to be partly a result of lettering size measured, measuring devices used, and individual observers.

  4. Rock Rinds at Meridiani and Surface Weathering Phenomena

    NASA Astrophysics Data System (ADS)

    Jolliff, B.; Knoll, A.; Farrand, W.; Sullivan, R.

    2006-12-01

    The Rock Abrasion Tool (RAT) on the Mars rover Opportunity can brush away surface dust and grind away outcrop surface, exposing presumably less altered rock at depths of several mm. Alpha particle X-ray spectrometer (APXS) and Moessbauer spectrometer (MB) analyses of pre- and post-RAT targets, thus, provide information on the chemical nature of weathering of Meridiani outcrop rocks. To date, Opportunity has analyzed some 25 undisturbed rock surfaces, brushed and then analyzed 7 more, and ground 23 targets for IDD analysis. Panoramic camera images show that outcrop surfaces are typically either buff or purple (as viewed in bands centered at 673, 535, and 432 nm, Farrand et al., JGR, in press). Relatively flat surfaces that are approximately parallel to the ground are typically buff, whereas those that slope steeply tend to be purple. Surfaces of rock interiors ground by the RAT are also commonly purple. Spectrally, these color differences correspond to more oxidized (buff) and less oxidized (purple), and appear to relate to the degree of eolian abrasion. Flat-lying surfaces are not eroded as quickly, thus surfaces chemically weathered by exposure to tenuous atmospheric vapor may be preserved. These observations are consistent with in-situ analyses of rock surfaces and interiors. Compared to interiors, rock surfaces have about 1/3 less S, and in general, surface compositions lie between those of rock interiors and average surface soil. In detail, they differ from soil-rock mixtures as follows: surfaces are relatively depleted in Mg, Fe, Mn, Ti, and Cr, and they are enriched in Al, Na, K, P, Cl, and Si. From MB analyses, surfaces are richer (compared to soil-rock mixtures) in oxidized Fe phases and poorer in magnetite, olivine, and pyroxene. Morphologically, numerous flat-lying rocks and outcrop surfaces that are at or near the ground surface have a rind of erosionally resistant material. Such rinds are also chemically distinct from outcrop interiors. A rind

  5. A New Perspective on Surface Weather Maps

    ERIC Educational Resources Information Center

    Meyer, Steve

    2006-01-01

    A two-dimensional weather map is actually a physical representation of three-dimensional atmospheric conditions at a specific point in time. Abstract thinking is required to visualize this two-dimensional image in three-dimensional form. But once that visualization is accomplished, many of the meteorological concepts and processes conveyed by the…

  6. Land surface skin temperatures from a combined analysis of microwave and infrared satellite observations for an all-weather evaluation of the differences between air and skin temperatures

    NASA Astrophysics Data System (ADS)

    Prigent, Catherine; Aires, Filipe; Rossow, William B.

    2003-05-01

    A neural network inversion scheme including first guess information has been developed to retrieve surface temperature Ts, along with atmospheric water vapor, cloud liquid water, and surface emissivities over land from a combined analysis of Special Sensor Microwave/Imager (SSM/I) and International Satellite Cloud Climatology Project (ISCCP) data. In the absence of routine in situ surface skin measurements, retrieved Ts values are evaluated by comparison to the surface air temperature Tair measured by the meteorological station network. The Ts - Tair difference shows all the expected variations with solar flux, soil characteristics, and cloudiness. During daytime the Ts - Tair difference is driven by the solar insulation, with positive differences that increase with increasing solar flux. With decreasing soil and vegetation moisture the evaporation rate decreases, increasing the sensible heat flux, thus requiring larger Ts - Tair differences. Nighttime Ts - Tair differences are governed by the longwave radiation balance, with Ts usually closer or lower than Tair. The presence of clouds dampens all the difference. After suppression of the variability associated to the diurnal solar flux variations, the Ts and Tair data sets show very good agreement in their synoptic variations, even for cloudy cases, with no bias and a global rms difference of ˜2.9 K. This value is an upper limit of the retrieval rms because it includes errors in the in situ data as well as errors related to imperfect time and space collocations between the satellite and in situ measurements.

  7. Characteristics of Operational Space Weather Forecasting: Observations and Models

    NASA Astrophysics Data System (ADS)

    Berger, Thomas; Viereck, Rodney; Singer, Howard; Onsager, Terry; Biesecker, Doug; Rutledge, Robert; Hill, Steven; Akmaev, Rashid; Milward, George; Fuller-Rowell, Tim

    2015-04-01

    In contrast to research observations, models and ground support systems, operational systems are characterized by real-time data streams and run schedules, with redundant backup systems for most elements of the system. We review the characteristics of operational space weather forecasting, concentrating on the key aspects of ground- and space-based observations that feed models of the coupled Sun-Earth system at the NOAA/Space Weather Prediction Center (SWPC). Building on the infrastructure of the National Weather Service, SWPC is working toward a fully operational system based on the GOES weather satellite system (constant real-time operation with back-up satellites), the newly launched DSCOVR satellite at L1 (constant real-time data network with AFSCN backup), and operational models of the heliosphere, magnetosphere, and ionosphere/thermosphere/mesophere systems run on the Weather and Climate Operational Super-computing System (WCOSS), one of the worlds largest and fastest operational computer systems that will be upgraded to a dual 2.5 Pflop system in 2016. We review plans for further operational space weather observing platforms being developed in the context of the Space Weather Operations Research and Mitigation (SWORM) task force in the Office of Science and Technology Policy (OSTP) at the White House. We also review the current operational model developments at SWPC, concentrating on the differences between the research codes and the modified real-time versions that must run with zero fault tolerance on the WCOSS systems. Understanding the characteristics and needs of the operational forecasting community is key to producing research into the coupled Sun-Earth system with maximal societal benefit.

  8. Generation of Multivariate Surface Weather Series with Use of the Stochastic Weather Generator Linked to Regional Climate Model

    NASA Astrophysics Data System (ADS)

    Dubrovsky, M.; Farda, A.; Huth, R.

    2012-12-01

    The regional-scale simulations of weather-sensitive processes (e.g. hydrology, agriculture and forestry) for the present and/or future climate often require high resolution meteorological inputs in terms of the time series of selected surface weather characteristics (typically temperature, precipitation, solar radiation, humidity, wind) for a set of stations or on a regular grid. As even the latest Global and Regional Climate Models (GCMs and RCMs) do not provide realistic representation of statistical structure of the surface weather, the model outputs must be postprocessed (downscaled) to achieve the desired statistical structure of the weather data before being used as an input to the follow-up simulation models. One of the downscaling approaches, which is employed also here, is based on a weather generator (WG), which is calibrated using the observed weather series and then modified (in case of simulations for the future climate) according to the GCM- or RCM-based climate change scenarios. The present contribution uses the parametric daily weather generator M&Rfi to follow two aims: (1) Validation of the new simulations of the present climate (1961-1990) made by the ALADIN-Climate/CZ (v.2) Regional Climate Model at 25 km resolution. The WG parameters will be derived from the RCM-simulated surface weather series and compared to those derived from observational data in the Czech meteorological stations. The set of WG parameters will include selected statistics of the surface temperature and precipitation (characteristics of the mean, variability, interdiurnal variability and extremes). (2) Testing a potential of RCM output for calibration of the WG for the ungauged locations. The methodology being examined will consist in using the WG, whose parameters are interpolated from the surrounding stations and then corrected based on a RCM-simulated spatial variability. The quality of the weather series produced by the WG calibrated in this way will be assessed in terms

  9. Use of meteorological satellite observations in weather modification programs

    NASA Technical Reports Server (NTRS)

    Dennis, A. S.; Smith, P. L., Jr.; Biswas, K. R.

    1973-01-01

    The potential value of weather satellite data in field operations of weather modification is appraised. It was found that satellites could play a useful role in operational weather modification projects, particularly in the recognition of treatment opportunities. Satellite cloud photographs and infrared observations appear promising in the identification of treatment opportunities in seeding orographic cloud systems for increased snowpack, in seeding convective clouds for increased rainfall, in identifying hail threats, and in tracking and observing hurricanes as an aid to timing and location of seeding treatments. It was concluded that the potential value of satellite data in the treatment and evaluation phases of operational projects is not as great as in the recognition of treatment opportunity.

  10. Observations of ionospheric electric fields above atmospheric weather systems

    SciTech Connect

    Farrell, W.M.; Aggson, T.L.; Rodgers, E.B.

    1994-10-01

    The authors report on the observations of a number of quasi-dc electric field events associated with large-scale atmospheric weather formations. The observations were made by the electric field experiment onboard the San Marco D satellite, operational in an equatorial orbit from May to December 1988. Several theoretical studies suggest that electric fields generated by thunderstorms are present at high altitudes in the ionosphere. In spite of such favorable predictions, weather-related events are not often observed since they are relatively weak. The authors report here on a set of likely E field candidates for atmosphere-ionosphere causality, these being observed over the Indonesian Basin, northern South America, and the west coast of Africa; all known sites of atmospheric activity. As they demonstrate, individual events can often be traced to specific active weather features. For example, a number of events were associated with spacecraft passages near Hurricane Joan in mid-October 1988. As a statistical set, the events appear to coincide with the most active regions of atmospheric weather. 31 refs., 11 figs., 1 tab.

  11. The National Eclipse Weather Experiment: an assessment of citizen scientist weather observations.

    PubMed

    Barnard, L; Portas, A M; Gray, S L; Harrison, R G

    2016-09-28

    The National Eclipse Weather Experiment (NEWEx) was a citizen science project designed to assess the effects of the 20 March 2015 partial solar eclipse on the weather over the United Kingdom (UK). NEWEx had two principal objectives: to provide a spatial network of meteorological observations across the UK to aid the investigation of eclipse-induced weather changes, and to develop a nationwide public engagement activity-based participation of citizen scientists. In total, NEWEx collected 15 606 observations of air temperature, cloudiness and wind speed and direction from 309 locations across the UK, over a 3 h window spanning the eclipse period. The headline results were processed in near real time, immediately published online, and featured in UK national press articles on the day of the eclipse. Here, we describe the technical development of NEWEx and how the observations provided by the citizen scientists were analysed. By comparing the results of the NEWEx analyses with results from other investigations of the same eclipse using different observational networks, including measurements from the University of Reading's Atmospheric Observatory, we demonstrate that NEWEx provided a fair representation of the change in the UK meteorological conditions throughout the eclipse. Despite the simplicity of the approach adopted, robust reductions in both temperature and wind speed during the eclipse were observed.This article is part of the themed issue 'Atmospheric effects of solar eclipses stimulated by the 2015 UK eclipse'. PMID:27550767

  12. Aviation Weather Observations for Supplementary Aviation Weather Reporting Stations (SAWRS) and Limited Aviation Weather Reporting Stations (LAWRS). Federal Meteorological Handbook No. 9.

    ERIC Educational Resources Information Center

    Department of Transportation, Washington, DC.

    This handbook provides instructions for observing, identifying, and recording aviation weather at Limited Aviation Weather Reporting Stations (LAWRS) and Supplementary Aviation Weather Reporting Stations (SAWRS). Official technical definitions, meteorological and administrative procedures are outlined. Although this publication is intended for use…

  13. Weather observations on Whistler Mountain during five storms

    NASA Astrophysics Data System (ADS)

    Thériault, Julie M.; Rasmussen, Kristen L.; Fisico, Teresa; Stewart, Ronald E.; Joe, Paul; Gultepe, Ismail; Clément, Marilys; Isaac, George A.

    2014-01-01

    A greater understanding of precipitation formation processes over complex terrain near the west coast of British Colombia will contribute to many relevant applications, such as climate studies, local hydrology, transportation, and winter sport competition. The phase of precipitation is difficult to determine because of the warm and moist weather conditions experienced during the wintertime in coastal mountain ranges. The goal of this study is to investigate the wide range of meteorological conditions that generated precipitation on Whistler Mountain from 4-12 March 2010 during the SNOW-V10 field campaign. During this time period, five different storms were documented in detail and were associated with noticeably different meteorological conditions in the vicinity of Whistler Mountain. New measurement techniques, along with the SNOW-V10 instrumentation, were used to obtain in situ observations during precipitation events along the Whistler mountainside. The results demonstrate a high variability of weather conditions ranging from the synoptic-scale to the macro-scale. These weather events were associated with a variation of precipitation along the mountainside, such as events associated with snow, snow pellets, and rain. Only two events associated with a rain-snow transition along the mountainside were observed, even though above-freezing temperatures along the mountainside were recorded 90 % of the time. On a smaller scale, these events were also associated with a high variability of snowflake types that were observed simultaneously near the top of Whistler Mountain. Overall, these detailed observations demonstrate the importance of understanding small-scale processes to improve observational techniques, short-term weather prediction, and longer-term climate projections over mountainous regions.

  14. Space based observations for monitoring extreme weather and climate events

    SciTech Connect

    Rao, P.K.

    1996-12-31

    Observations are essential for monitoring, understanding, and predicting the potential for extreme weather and climate events. These events occur on all time and spatial scales. Current NOAA operational satellites have a unique capability of providing many of the observations that are critical for monitoring these events. These observations and derived geophysical quantities can also be used for diagnostics and prediction purposes. Extreme weather conditions such as severe thunderstorms and flash floods, occur very quickly, may last for a short time, and create a considerable amount of damage. Advance warnings of the order of a few minutes are needed to alert the public so they may take adequate precautions. Some extreme weather conditions such as tropical storms (hurricanes) may last for days, and in order to predict the exact track, intensity of the storm and forecast the land fall, frequent observations are critical. Examples of satellite data that are obtained from the NOAA satellites are presented to demonstrate their ability to monitor the extreme weather phenomena. Examples of extreme climate conditions are droughts over continents and the annual depletion of ozone over the Antarctic. Data derived from NOAA satellites were used to monitor the severe drought over Texas and Southwestern U.S.A. in early 1996. Similar data are being used by other countries to monitor the drought in their regions. The development of the ozone hole over the Antarctic during the last fifteen years has been a major scientific and environmental concern. Data from NOAA operational satellites have been extensively used to show the yearly development and dissipation of the ozone hole during the Southern Hemisphere springtime.

  15. Standardisation of temperature observed by automatic weather stations.

    PubMed

    Joyce, A; Adamson, J; Huntley, B; Parr, T; Baxter, R

    2001-05-01

    Daily mean, maximum and minimum surface air temperature data were gathered from a network of automatic weather stations (AWS) within the Moor House National Nature Reserve in northern England. Five AWS were installed next to the official Environmental Change Network weather station at Moor House. Data were compared graphically and correction constants were calculated to adjust data from each AWS to the standard of the official station by optimising the concordance correlation coefficient. Each corrected station was re-located next to one of five in-situ stations in and around the reserve, allowing correction of all temperature sensors to a common standard. The mean error associated with measured daily mean, maximum and minimum temperature for each sensor does not exceed +/- 0.2 K. The procedure quantifies a source of systematic measurement error, improving the identification of spatial temperature differences between stations. PMID:11411140

  16. DAWN observations of Vesta versus lunar-type space weathering

    NASA Astrophysics Data System (ADS)

    Kohout, Tomas; Malina, Ondrej; Penttila, Antti; Kroger, Anni; Britt, Daniel; Fillip, Jan; Muinonen, Karri; Zboril, Radek

    2015-11-01

    The major reason for spectral changes in lunar-type space weathering is production of nanophase iron (npFe0) in the lunar regolith. The spectral changes include attenuation of silicate absorption bands, darkening, and slope change (reddening). Spectral observations of the asteroid Vesta by DAWN mission revealed a different pattern. The darkening and the absorption band attenuation occur in similar way as on the Moon. The reddening, however, is not apparent. Thus, is space weathering on Vesta different from that we see on the Moon?In order to study effects of npFe0 on thereflectance spectra, pyroxene (En 90) and howardite (NWA 1929) powder samples were subjected to the space weathering experiments. Both enstatite and howardite show progressive changes in their spectra as a function of the increasing npFe0 amount. An interesting feature is observed in the comparison of the slope over the 1 and 2 µm bands in both pyroxene and howardite. While the slope over 2 µm band show progressive reddening with increasing npFe0 amount (similarly to olivine), the situation is reversed in the 1 µm band region. The relative reduction in the spectral slope is observed in this region.This is due to the fact that the decrease in reflectance when adding npFe0 is a nonlinear process where higher reflectance values will decrease more than lower values. If the original slope is positive, as the slope over the 1 µm band in pyroxene and howardite, the slope will flatten with increasing npFe0 (relative bluing).This finding can potentially explain some of the space weathering observations for Vesta. The majority of the DAWN observations were done in the 1 µm region where the lack of reddening is observed, similar to our pyroxene and howardite results. Thus, the lack of reddening over the 1 µm region as observed on Vesta does not contradict the space weathering mechanism driven by the presence of npFe0. In order to confirm this more NIR data from Vesta are needed over the 2 µm region

  17. Imbalanced land surface water budgets in a numerical weather prediction system

    NASA Astrophysics Data System (ADS)

    Kauffeldt, Anna; Halldin, Sven; Pappenberger, Florian; Wetterhall, Fredrik; Xu, Chong-Yu; Cloke, Hannah L.

    2015-06-01

    There has been a significant increase in the skill and resolution of numerical weather prediction models (NWPs) in recent decades, extending the time scales of useful weather predictions. The land surface models (LSMs) of NWPs are often employed in hydrological applications, which raises the question of how hydrologically representative LSMs really are. In this paper, precipitation (P), evaporation (E), and runoff (R) from the European Centre for Medium-Range Weather Forecasts global models were evaluated against observational products. The forecasts differ substantially from observed data for key hydrological variables. In addition, imbalanced surface water budgets, mostly caused by data assimilation, were found on both global (P-E) and basin scales (P-E-R), with the latter being more important. Modeled surface fluxes should be used with care in hydrological applications, and further improvement in LSMs in terms of process descriptions, resolution, and estimation of uncertainties is needed to accurately describe the land surface water budgets.

  18. Physical and chemical weathering. [of Martian surface and rocks

    NASA Technical Reports Server (NTRS)

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

    1992-01-01

    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.

  19. Mobile vehicle road and weather observation quality check methods

    NASA Astrophysics Data System (ADS)

    Koller, Daniel Raymond

    data quality and accuracy, requiring the development of quality checks for mobile data collection. Using OBDII-equipped automobiles and mobile collection methods, we can begin to address issues of data quality by understanding, characterizing, and demonstrating the quality of mobile system observations from operational and research environments. Several forms of quality checking can be used, including range checks, Barnes spatial checks, comparing vehicle data to road weather models, and applying Clarus quality check methodologies and algorithms to mobile observations. Development of these quality checks can lead to the future integration of mobile data into the Clarus system, data implementation for improved forecasting, maintenance decision support, and traveler safety. This paper will discuss the benefits and challenges in mobile data collection, along with how the development and implementation of a system of quality checks will improve the quality and accuracy of mobile data collection.

  20. Space weathering of asteroids as observable with GAIA

    NASA Astrophysics Data System (ADS)

    Kanuchova, Z.; Brunetto, R.; Fulvio, D.; Strazzulla, G.

    2015-10-01

    Among the scientific objectives of the GAIA mission, there is great scientific interest in detecting asteroids and comets in our Solar System. In the next years, GAIA is expected to strongly contribute to this search because of its unprecedented sensitivity to faint, moving objects. We investigate how to use the spectrophotometric data of asteroids that GAIA is in the process of acquiring (scientific mission started in summer 2014 for 5 years) to evidence space weathering processes. Along with asteroid spectral reflectivities, one of the products are the Spectra Shape Coefficients, a sort of colours obtained by integrating the spectra in predefined bands. To this end we have checked which colours, among those chosen by the GAIA team as wavelengths for the spectral shape coefficients, can be more useful to evidence the spectral alteration induced by space weathering as simulated in the laboratory by irradiation with energetic ions and pulsed lasers. We show that a diagram plotting the colour index SSC530-SSC953 vs the SSC752-SSC953 one, well defines a region where the GAIA observations of S-type asteroids and Vestoids can evidence the space weathering experienced by the observed objects.

  1. Observational and modelling studies of Australian severe weather

    NASA Astrophysics Data System (ADS)

    Speer, Milton Samuel

    1998-09-01

    The forecastability of severe weather conditions over sub-tropical Australia are tested with a mesoscale model capable of running at high resolutions over a region of interest anywhere in the world. Improved forecast output, for example, of precipitation, wind speed/direction and humidity which are required to indicate severe weather conditions are dependent on model improvements and the following areas are addressed: (1)data; (2)theory; (3)model; and, (4)computing. The initial condition uncertainty inherent in the data which is used in the analysis to initialise numerical weather prediction (NWP) models is addressed through two ensemble forecasting studies, one on rainfall from a mesoscale system and the other on the central low position, wind and rainfall distribution of an explosive east coast low. Also, relating to data, some major mesoscale phenomena are described in the form of New South Wales coastal ridging which helps produce severe weather in this area and which needs to be captured by a mesoscale NWP model in order that improved predictions can be made. In terms of theory the major focus is on the ensemble methodology and on the use of improved precipitation parameterisations, namely, those of Fritsch-Chappell and Kain-Fritsch. The mesoscale model development is extended through the use of increased resolution studies, for example, by showing statistically significant greater than operational skill in predicting details of wind, relative humidity and temperature patterns both near the surface and above the boundary layer in relation to the Sydney January 1994 bushfire weather; by including an option for a Lagrangian particle dispersion model; and by replacement of a previously inadequate representation of cumulus convection which was required to represent the effects of mesoscale downdrafts which are essential for the successful prediction of the squall-line over Sydney in Chapter 7. Mesoscale weather prediction is one of the so called `grand challenges

  2. Land-surface influences on weather and climate

    NASA Technical Reports Server (NTRS)

    Baer, F.; Mintz, Y.

    1984-01-01

    Land-surface influences on weather and climate are reviewed. The interrelationship of vegetation, evapotranspiration, atmospheric circulation, and climate is discussed. Global precipitation, soil moisture, the seasonal water cycle, heat transfer, and atmospheric temperature are among the parameters considered in the context of a general biosphere model.

  3. Near surface observations

    NASA Technical Reports Server (NTRS)

    1982-01-01

    Learning objectives include: (1) developing an understanding of the implications of the term "near surface observations"; (2) associating the appearance of large ground features as seen in satellite imagery with their appearance as seen from the ground; (3) grasping criteria and procedures for selecting training sites on the ground for use in supervised classification; (4) running through an example of training site selection; (5) becoming familiar with several methods of accuracy assessment; (6) becoming aware of the approach and value of making supporting measurements of the spectral and physical properties of materials on the ground and from aircraft; (7) taking note of the different types of instruments used in making specific ground measurements; and (8) appreciating the rationale underlying laboratory and field studies on or near the Earth's surface for the purpose of developing new sensor systems.

  4. Solar observations from PROBA2: ready for space weather operations

    NASA Astrophysics Data System (ADS)

    Berghmans, David; Hochedez, Jean-François

    The ESA micro satellite PROBA2 was launched on November 2, 2009. It carries two solar instruments, the radiometer LYRA and the coronal imager SWAP whose commissioning ended in March 2010. LYRA (PI: J.-F. Hochedez) observes the solar irradiance in 4 wavelengths chosen for their relevance to space weather, solar physics and Earth aeronomy. LYRA is able to follow the time evolution of solar flares at very high temporal resolution. SWAP (PI: D. Berghmans) takes an image of the EUV corona of the sun every minute in an extended field of view. SWAP is able to image all space weather significant events such as flares, coronal holes, dimmings, etc. We will present the technical capabilities of the two instruments and show their complementarity with e.g. SDO. We will discuss the SWAP and LYRA data products and how to make use of them in an operational space weather context. More information is available at http://proba2.sidc.be.

  5. Infrared spectroscopy of weathering products in a terrestrial glacial environment: Implications for cold weathering on planetary surfaces

    NASA Astrophysics Data System (ADS)

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

    2011-12-01

    Geologic features on Mars show evidence of modification by water and water ice. Past obliquity variations are hypothesized to have allowed the formation and stability of ground ice near the equator, possibly promoting the accumulation of glaciers. Massive ice deposits, including probable glacial and periglacial features have also been observed in the east Hellas Basin and Deuteronilus Mensae regions, located at the midlatitudes of Mars. These features indicate present-day, near-surface ice has been in contact with geologic materials, creating an environment in which cold weathering processes could have been occurring, and might still be at work. Weathering processes in cold terrestrial environments are not well understood, and processes acting on subglacial and englacial sediments and rocks are not well characterized due to the remote location of many glaciers and the difficulty of collecting samples. The types of weathering products and energy sources produced in a glacial environment will drive the overall energy budget for any microbial communities present. The subglacial energy budget for microbes thus has implications in the search for life on other planets, making glacial and periglacial terrains excellent sites for future exploration. However, planetary ice deposits are difficult to study due to their sensitive nature and are thus limited to observation from orbit at present. It is therefore a key concern to better understand the types materials and alteration products that can be observed and constrained from orbital data. In this study, we characterize the types of weathering products present in a glacial system using ground-truthed remote sensing techniques. Robertson Glacier, Alberta, Canada (115°20'W, 50°44'N) provides an excellent testbed for this technique as it is accessible, and its recent and continuing retreat allows fresh subglacial and englacial sediments to be sampled. Samples of bedrock and glacially altered rock and sediments were collected

  6. Observed Weather Satellite Thermal IR Responses Prior to Earthquakes

    NASA Astrophysics Data System (ADS)

    Bryant, N. A.; Zobrist, A. L.; Logan, L. L.; Freund, F.; Nishenko, S.

    2002-12-01

    A number of observers claim to have seen thermal anomalies prior to earthquakes, but subsequent analysis by others have failed to produce similar findings. It was the purpose of this study to determine if thermal anomalies could be found in association with known earthquakes by systematically co-registering weather satellite images at the sub-pixel level and then determining if statistically significant responses had occurred prior to an event. Earthquakes associated with plate movement (strike-slip and thrust faulting), rather than volcanism, were to be considered. A new set of automatic co-registration procedures were developed for this task to accommodate all properties particular to weather satellite observations taken at night. Spacecraft and sensor ephemeris and the horizontal displacement due to elevation were all factored in, and final adjustment for minor satellite deviations (related to roll, pitch, and yaw) were made by using image-to-image tiepoint correlations. Reliance upon visual clues in an image (frequently the subject of debate in the past) is not required. The technique relies on the general condition where ground cools after sunset. The technique applies best to the use of the geosynchronous weather satellites (GOES, Meteosat, and GMS), where images are taken every thirty minutes. Use of the geosynchronous satellites also reduces the potential for miscalculation of trends due to weather front movement or local cloud/fog formation. The polar orbiting satellites have better resolution (1km vs 5km) and better signal-to-noise, but only acquire images twice during an evening, thereby making trend analysis difficult. Case studies investigated to date include the Hector Mine California and Ikrit Turkey earthquakes of 1999, and the Bhuj India quake of 2001. The result of the new analytic procedures has been the observance of apparent heating trends close to epicenters in satellite data acquisitions a few hours prior to an earthquake. When observations

  7. Structural analysis of heat-treated birch (Betule papyrifera) surface during artificial weathering

    NASA Astrophysics Data System (ADS)

    Huang, Xianai; Kocaefe, Duygu; Kocaefe, Yasar; Boluk, Yaman; Krause, Cornélia

    2013-01-01

    Effect of artificial weathering on the surface structural changes of birch (Betule papyrifera) wood, heat-treated to different temperatures, was studied using the fluorescence microscopy and the scanning electron microscopy (SEM). Changes in the chemical structure of wood components were analyzed by FTIR in order to understand the mechanism of degradation taking place due to heat treatment and artificial weathering. The results are compared with those of the untreated (kiln-dried) birch. The SEM analysis results show that the effect of weathering on the cell wall of the untreated birch surface is more than that of heat-treated samples. The FTIR spectroscopy results indicate that lignin is the most sensitive component of heat-treated birch to the weathering degradation process. Elimination of the amorphous and highly crystallised cellulose is observed for both heat-treated and untreated wood during weathering. It is also observed that heat treatment increases the lignin and crystallised cellulose contents, which to some extent protects heat-treated birch against degradation due to weathering.

  8. A climatological link between slantwise instability and surface weather conditions

    NASA Astrophysics Data System (ADS)

    Glinton, M. R.; Gray, S. L.; Chagnon, J. M.; Morcrette, C. J.

    2012-04-01

    Midlatitude weather phenomena including rainbands in fronts and cloud heads and the descending sting jets found in extreme windstorms have been attributed, in part, to the release of conditional symmetric instability (CSI). CSI is a slantwise parcel instability arising from the combination of inertial and gravitational instability in a baroclinic atmosphere; its release gives slantwise convection. However, to date, demonstration of the link between CSI and severe weather has been confined to a few case studies. Weather forecast models with domains big enough to encompass entire midlatitude storms do not have sufficient resolution to realistically resolve the release of CSI, and CSI release is not parameterized in these models. The consequences of this lack of representation of CSI release are currently unknown and motivate this study. We present a North Atlantic climatology of the energy available for slantwise convection due to CSI derived from the ERA-Interim re-analysis, and compare it with an equivalent climatology of CAPE (the energy available for upright convection due to conditional instability). The annual cycle of land and sea surface temperatures are shown to strongly modulate these instabilities. The statistical relationship between these instabilities and surface weather conditions are presented.

  9. Global cloud climatology from surface observations

    SciTech Connect

    Warren, S.

    1995-09-01

    Surface weather observations from stations on land and ships in the ocean are used to obtain the global distribution, at 5{sup o}x5{sup o} latitude-longitude resolution, of total cloud cover and the average amounts of the different cloud types: cumulus, cumulonimbus, stratus, stratocumulus, nimbostratus, altostratus, altocumulus, cirrus, cirrostratus, cirrocumulus, and fog. Diurnal and seasonal variations are derived, as well as interannual variations and multi-year trends. 3 refs., 3 figs.

  10. Near Real Time MISR Wind Observations for Numerical Weather Prediction

    NASA Astrophysics Data System (ADS)

    Mueller, K. J.; Protack, S.; Rheingans, B. E.; Hansen, E. G.; Jovanovic, V. M.; Baker, N.; Liu, J.; Val, S.

    2014-12-01

    The Multi-angle Imaging SpectroRadiometer (MISR) project, in association with the NASA Langley Atmospheric Science Data Center (ASDC), has this year adapted its original production software to generate near-real time (NRT) cloud-motion winds as well as radiance imagery from all nine MISR cameras. These products are made publicly available at the ASDC with a latency of less than 3 hours. Launched aboard the sun-synchronous Terra platform in 1999, the MISR instrument continues to acquire near-global, 275 m resolution, multi-angle imagery. During a single 7 minute overpass of any given area, MISR retrieves the stereoscopic height and horizontal motion of clouds from the multi-angle data, yielding meso-scale near-instantaneous wind vectors. The ongoing 15-year record of MISR height-resolved winds at 17.6 km resolution has been validated against independent data sources. Low-level winds dominate the sampling, and agree to within ±3 ms-1 of collocated GOES and other observations. Low-level wind observations are of particular interest to weather forecasting, where there is a dearth of observations suitable for assimilation, in part due to reliability concerns associated with winds whose heights are assigned by the infrared brightness temperature technique. MISR cloud heights, on the other hand, are generated from stereophotogrammetric pattern matching of visible radiances. MISR winds also address data gaps in the latitude bands between geostationary satellite coverage and polar orbiting instruments that obtain winds from multiple overpasses (e.g. MODIS). Observational impact studies conducted by the Naval Research Laboratory (NRL) and by the German Weather Service (Deutscher Wetterdienst) have both demonstrated forecast improvements when assimilating MISR winds. An impact assessment using the GEOS-5 system is currently in progress. To benefit air quality forecasts, the MISR project is currently investigating the feasibility of generating near-real time aerosol products.

  11. Surface Landing Site Weather Analysis for NASA's Constellation Program

    NASA Technical Reports Server (NTRS)

    Altino, Karen M.; Burns, K. L.

    2008-01-01

    Weather information is an important asset for NASA's Constellation Program in developing the next generation space transportation system to fly to the International Space Station, the Moon and, eventually, to Mars. Weather conditions can affect vehicle safety and performance during multiple mission phases ranging from pre-launch ground processing of the Ares vehicles to landing and recovery operations, including all potential abort scenarios. Meteorological analysis is art important contributor, not only to the development and verification of system design requirements but also to mission planning and active ground operations. Of particular interest are the surface weather conditions at both nominal and abort landing sites for the manned Orion capsule. Weather parameters such as wind, rain, and fog all play critical roles in the safe landing of the vehicle and subsequent crew and vehicle recovery. The Marshall Space Flight Center (MSFC) Natural Environments Branch has been tasked by the Constellation Program with defining the natural environments at potential landing zones. This paper wiI1 describe the methodology used for data collection and quality control, detail the types of analyses performed, and provide a sample of the results that cab be obtained.

  12. Personal Computers, Weather Observations, and the National Climatic Data Center.

    NASA Astrophysics Data System (ADS)

    Heim, Richard, Jr.

    1988-05-01

    The personal computer (PC) has become an important part of meteorological observing, telecommunications, forecasting, research, and data-management systems. The National Climatic Data Center (NCDC) is the nation's quality-control and archival facility for weather data. NCDC's digital archive consists of more than 200 data sets which are stored on over 50 000 reels of high-density magnetic tape. Its size and complexity make on-line access to the complete archive via PC and modem impractical. However, NCDC recognizes the growing importance of PCs in climatic applications and, since 1984, has made selected data sets available in a PC-readable format.The data sets available on diskette fall into the following broad categories: hourly observations, daily observations, derived quantities, and summary statistics. The period of record varies with each data set and with each station. In the digital archive, daily observations generally begin in the late 1800's to the early 1900's, and hourly observations generally begin in the mid 1900's.A review of NCDC data operations and products puts the digital archive into an operational perspective. The two formats (BASIC sequential element, and fixed-position fields) in which data-set diskettes are available are sumniafized. BASIC-sequential-element files can be "imported" into a LOTUS-type spreadsheet.NCDC is also responsible for describing the nation's climate. These functions have been condensed into a climatological data-management and analysis software package, called CLICOM, which can be run on a PC.

  13. Effect of accelerated weathering on surface chemistry of modified wood

    NASA Astrophysics Data System (ADS)

    Temiz, Ali; Terziev, Nasko; Eikenes, Morten; Hafren, Jonas

    2007-04-01

    In this study, the effects of UV-light irradiation and water spray on colour and surface chemistry of scots pine sapwood samples were investigated. The specimens were treated with chromated copper arsenate (CCA), a metal-free propiconazol-based formulation, chitosan, furfuryl alcohol and linseed and tall oils. The weathering experiment was performed by cycles of 2 h UV-light irradiation followed by water spray for 18 min. The changes at the surface of the weathered samples were characterised by Fourier transform infrared spectroscopy (FT-IR); colour characterizations were performed by measuring CIELab parameters. The results show that all treatment methods except chitosan treatment provided lower colour changes than the control groups after 800 h exposure in weathering test cycle, but differences between chitosan and control were also small. The lowest colour changes were found on linseed oil (full cell process) and CCA treated wood. FT-IR results show that oil treatment (linseed and tall oil) decreased the intensities of a lignin specific peak (1500-1515 cm -1). Absorption band changes at 1630-1660 cm -1 were reduced by all treatments.

  14. Surface weathering and dispersibility of MC252 crude oil.

    PubMed

    Daling, Per S; Leirvik, Frode; Almås, Inger Kjersti; Brandvik, Per Johan; Hansen, Bjørn Henrik; Lewis, Alun; Reed, Mark

    2014-10-15

    Results from a comprehensive oil weathering and dispersant effectiveness study of the MC252 crude oil have been used to predict changes in oil properties due to weathering on the sea surface and to estimate the effective "time window" for dispersant application under various sea conditions. MC252 oil is a light paraffinic crude oil, for which approximately 55 wt.% will evaporate within 3-5 days when drifting on the sea. An unstable and low-viscosity water-in-oil (w/o) emulsion are formed during the first few days at the sea surface. This allows a high degree of natural dispersion when exposed to breaking wave conditions. Under calm sea conditions, a more stable and light-brown/orange colored water-in-oil (w/o) emulsion may start to form after several days, and viscosities of 10,000-15,000 mPa s can be achieved after 1-2 weeks. The "time window" for effective use of dispersants was estimated to be more than 1 week weathering at sea. PMID:25152185

  15. Modeling apple surface temperature dynamics based on weather data.

    PubMed

    Li, Lei; Peters, Troy; Zhang, Qin; Zhang, Jingjin; Huang, Danfeng

    2014-01-01

    The exposure of fruit surfaces to direct sunlight during the summer months can result in sunburn damage. Losses due to sunburn damage are a major economic problem when marketing fresh apples. The objective of this study was to develop and validate a model for simulating fruit surface temperature (FST) dynamics based on energy balance and measured weather data. A series of weather data (air temperature, humidity, solar radiation, and wind speed) was recorded for seven hours between 11:00-18:00 for two months at fifteen minute intervals. To validate the model, the FSTs of "Fuji" apples were monitored using an infrared camera in a natural orchard environment. The FST dynamics were measured using a series of thermal images. For the apples that were completely exposed to the sun, the RMSE of the model for estimating FST was less than 2.0 °C. A sensitivity analysis of the emissivity of the apple surface and the conductance of the fruit surface to water vapour showed that accurate estimations of the apple surface emissivity were important for the model. The validation results showed that the model was capable of accurately describing the thermal performances of apples under different solar radiation intensities. Thus, this model could be used to more accurately estimate the FST relative to estimates that only consider the air temperature. In addition, this model provides useful information for sunburn protection management. PMID:25350507

  16. Modeling Apple Surface Temperature Dynamics Based on Weather Data

    PubMed Central

    Li, Lei; Peters, Troy; Zhang, Qin; Zhang, Jingjin; Huang, Danfeng

    2014-01-01

    The exposure of fruit surfaces to direct sunlight during the summer months can result in sunburn damage. Losses due to sunburn damage are a major economic problem when marketing fresh apples. The objective of this study was to develop and validate a model for simulating fruit surface temperature (FST) dynamics based on energy balance and measured weather data. A series of weather data (air temperature, humidity, solar radiation, and wind speed) was recorded for seven hours between 11:00–18:00 for two months at fifteen minute intervals. To validate the model, the FSTs of “Fuji” apples were monitored using an infrared camera in a natural orchard environment. The FST dynamics were measured using a series of thermal images. For the apples that were completely exposed to the sun, the RMSE of the model for estimating FST was less than 2.0 °C. A sensitivity analysis of the emissivity of the apple surface and the conductance of the fruit surface to water vapour showed that accurate estimations of the apple surface emissivity were important for the model. The validation results showed that the model was capable of accurately describing the thermal performances of apples under different solar radiation intensities. Thus, this model could be used to more accurately estimate the FST relative to estimates that only consider the air temperature. In addition, this model provides useful information for sunburn protection management. PMID:25350507

  17. Surface ozone concentration trends and its relationship with weather types in Spain (2001-2010)

    NASA Astrophysics Data System (ADS)

    Santurtún, Ana; González-Hidalgo, José Carlos; Sanchez-Lorenzo, Arturo; Zarrabeitia, María Teresa

    2015-01-01

    This paper assesses the temporal variations of surface ozone concentrations during the period 2001-2010 in 3 regions of Spain with different geographical and socioeconomic features (northern coastland, central inland and northeast inland), as well as its link with atmospheric circulation. Specifically, daily surface atmospheric patterns over the aforementioned regions are characterized using NCEP/NCAR reanalysis data and an objective classification scheme in order to study the relationship between synoptic weather types and daily ozone levels. The results show that tropospheric ozone concentration has a tendency towards an increase during the study period, both during daytime and nighttime. Moreover, in general, this upward trend is seen throughout all of the seasons. The observed trends are in line with a reported decrease of NOX emissions and increase in surface solar radiation during the 2000s in Spain. On the other hand, interestingly, median concentrations were statistically significantly lower in days with anticyclonic weather conditions than in the rest of meteorological situations, while days with a directional weather type showed higher median levels of ozone concentration, with maximum values in days with northern and eastern component. Due to the detrimental effect that ozone has on human health, the relationship between synoptic weather patterns and daily ozone levels shown in this work could potentially be used for implementing pollution level alert protocols depending on forecast weather types.

  18. Direct observations of aluminosilicate weathering in the hyporheic zone of an Antarctic Dry Valley stream

    NASA Astrophysics Data System (ADS)

    Maurice, Patricia A.; McKnight, Diane M.; Leff, Laura; Fulghum, Julia E.; Gooseff, Michael

    2002-04-01

    This study focused on chemical weathering and bacterial ecology in the hyporheic zone of Green Creek, a McMurdo Dry Valley (Antarctica) stream. An in situ microcosm approach was used to observe dissolution features on the basal-plane surface of muscovite mica. Four mica chips were buried in December 1999 and dug up 39 d later. Atomic force microscopy (AFM) of the basal-plane surfaces revealed small, anhedral ˜10-Å-deep etch pits covering ˜4% of the surfaces, from which an approximate basal-plane dissolution rate of 8.3 × 10 -18 mol muscovite cm -2 s -1 was calculated (on the basis of the geometric surface area) for the study period. This is an integrated initial dissolution rate on a fresh surface exposed for a relatively brief period over the austral summer and should not be compared directly to other long-term field rates. The observation of weathering features on mica agrees with previous stream- and watershed-scale studies in the Dry Valleys, which have demonstrated that weathering occurs where liquid water is present, despite the cold temperatures. AFM imaging of mica surfaces revealed biofilms including numerous small (<1 μm long), rounded, oblong bacteria. The AFM observations agreed well with X-ray photoelectron microscopy results showing increased organic C and N. Bacteriologic analysis of the hyporheic zone sediments also revealed <1-μm-long bacteria. α-Proteobacteria were observed, consistent with the oligotrophic conditions of the hyporheic zone. Nitrate-reducing bacteria were found, in agreement with a previous tracer test at Green Creek that suggested nitrate reduction occurs in the hyporheic zone. The results of this study thus provide direct evidence of dynamic geochemical and microbial processes in the hyporheic zone of a Dry Valley stream despite the extreme conditions; such processes were inferred previously from stream-scale hydrogeochemical studies.

  19. Weather.

    ERIC Educational Resources Information Center

    Web Feet K-8, 2000

    2000-01-01

    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)

  20. Widespread Weathered Glass on the Surface of Mars

    NASA Technical Reports Server (NTRS)

    Horgan, Briony; Bell, James F., III

    2012-01-01

    Low albedo sediments cover >10(exp 7) sq km in the northern lowlands of Mars, but the composition and origin of these widespread deposits have remained ambiguous despite many previous investigations. Here we use near-infrared spectra acquired by the Mars Express OMEGA (Observatoire pour la Mineralogie, l'Eau, les Glaces, et l'Activite') imaging spectrometer to show that these sediments exhibit spectral characteristics that are consistent with both high abundances of iron-bearing glass and silica-enriched leached rinds on glass. This interpretation is supported by observations of low-albedo soil grains with possible rinds at the Phoenix Mars Lander landing site in the northern lowlands. By comparison with the extensive glass-rich dune fields and sand sheets of Iceland, we propose an explosive volcanic origin for these glass-rich sediments. We also propose that the glassy remnant rinds on the sediments are the result of post-depositional alteration, as these rinds are commonly formed in arid terrestrial volcanic environments during water-limited, moderately acidic leaching. These weathered, glass-rich deposits in the northern lowlands are also colocated with the strongest concentrations of a major global compositional surface type previously identified in mid-infrared spectra, suggesting that they may be representative of global processes. Our results provide potential confirmation of models suggesting that explosive volcanism has been widespread on Mars, and also raise the possibilities that glass-rich volcaniclastics are a major source of eolian sand on Mars and that widespread surficial aqueous alteration has occurred under Amazonian climatic conditions.

  1. Lightning Sensors for Observing, Tracking and Nowcasting Severe Weather

    PubMed Central

    Price, Colin

    2008-01-01

    Severe and extreme weather is a major natural hazard all over the world, often resulting in major natural disasters such as hail storms, tornados, wind storms, flash floods, forest fires and lightning damages. While precipitation, wind, hail, tornados, turbulence, etc. can only be observed at close distances, lightning activity in these damaging storms can be monitored at all spatial scales, from local (using very high frequency [VHF] sensors), to regional (using very low frequency [VLF] sensors), and even global scales (using extremely low frequency [ELF] sensors). Using sensors that detect the radio waves emitted by each lightning discharge, it is now possible to observe and track continuously distant thunderstorms using ground networks of sensors. In addition to the number of lightning discharges, these sensors can also provide information on lightning characteristics such as the ratio between intra-cloud and cloud-to-ground lightning, the polarity of the lightning discharge, peak currents, charge removal, etc. It has been shown that changes in some of these lightning characteristics during thunderstorms are often related to changes in the severity of the storms. In this paper different lightning observing systems are described, and a few examples are provided showing how lightning may be used to monitor storm hazards around the globe, while also providing the possibility of supplying short term forecasts, called nowcasting.

  2. Optical space weathering on Vesta: Radiative-transfer models and Dawn observations

    NASA Astrophysics Data System (ADS)

    Blewett, David T.; Denevi, Brett W.; Le Corre, Lucille; Reddy, Vishnu; Schröder, Stefan E.; Pieters, Carle M.; Tosi, Federico; Zambon, Francesca; De Sanctis, Maria Cristina; Ammannito, Eleonora; Roatsch, Thomas; Raymond, Carol A.; Russell, Christopher T.

    2016-02-01

    Exposure to ion and micrometeoroid bombardment in the space environment causes physical and chemical changes in the surface of an airless planetary body. These changes, called space weathering, can strongly influence a surface's optical characteristics, and hence complicate interpretation of composition from reflectance spectroscopy. Prior work using data from the Dawn spacecraft (Pieters, C.M. et al. [2012]. Nature 491, 79-82) found that accumulation of nanophase metallic iron (npFe0), which is a key space-weathering product on the Moon, does not appear to be important on Vesta, and instead regolith evolution is dominated by mixing with carbonaceous chondrite (CC) material delivered by impacts. In order to gain further insight into the nature of space weathering on Vesta, we constructed model reflectance spectra using Hapke's radiative-transfer theory and used them as an aid to understanding multispectral observations obtained by Dawn's Framing Cameras (FC). The model spectra, for a howardite mineral assemblage, include both the effects of npFe0 and that of a mixed CC component. We found that a plot of the 438-nm/555-nm ratio vs. the 555-nm reflectance for the model spectra helps to separate the effects of lunar-style space weathering (LSSW) from those of CC-mixing. We then constructed ratio-reflectance pixel scatterplots using FC images for four areas of contrasting composition: a eucritic area at Vibidia crater, a diogenitic area near Antonia crater, olivine-bearing material within Bellicia crater, and a light mantle unit (referred to as an "orange patch" in some previous studies, based on steep spectral slope in the visible) northeast of Oppia crater. In these four cases the observed spectral trends are those expected from CC-mixing, with no evidence for weathering dominated by production of npFe0. In order to survey a wider range of surfaces, we also defined a spectral parameter that is a function of the change in 438-nm/555-nm ratio and the 555-nm reflectance

  3. Surface Meteorological Observation System (SMOS) Handbook

    SciTech Connect

    Ritsche, MT

    2008-03-01

    The Surface Meteorological Observation System (SMOS) mostly uses conventional in situ sensors to obtain 1-minute, 30-minute, and 1440-minute (daily) averages of surface wind speed, wind direction, air temperature, relative humidity (RH), barometric pressure, and precipitation at the Central Facility and many of the extended facilities of the Southern Great Plains (SGP) climate research site. The SMOSs are not calibrated as systems. The sensors and the data logger (which includes the analog-to-digital converter, or A/D) are calibrated separately. All systems are installed using components that have a current calibration. SMOSs have not been installed at extended facilities located within about 10 km of existing surface meteorological stations, such as those of the Oklahoma Mesonet. The Surface Meteorological Observation Systems are used to create climatology for each particular location, and to verify the output of numerical weather forecast and other model output. They are also used to “ground-truth” other remote sensing equipment.

  4. WEATHER OBSERVATIONS - SUMMARY OF THE DAY - FIRST ORDER

    EPA Science Inventory

    The National Climatic Data Center makes available daily weather data for approximately 300 currently active National Weather Service stations, with a lag time (after end of data month) of about 8-10 weeks. Coverage includes the contiguous United States, Caribbean Islands, Pacific...

  5. Aviation & Space Weather Policy Research: Integrating Space Weather Observations & Forecasts into Operations

    NASA Astrophysics Data System (ADS)

    Fisher, G.; Jones, B.

    2006-12-01

    The American Meteorological Society and SolarMetrics Limited are conducting a policy research project leading to recommendations that will increase the safety, reliability, and efficiency of the nation's airline operations through more effective use of space weather forecasts and information. This study, which is funded by a 3-year National Science Foundation grant, also has the support of the Federal Aviation Administration and the Joint Planning and Development Office (JPDO) who is planning the Next Generation Air Transportation System. A major component involves interviewing and bringing together key people in the aviation industry who deal with space weather information. This research also examines public and industrial strategies and plans to respond to space weather information. The focus is to examine policy issues in implementing effective application of space weather services to the management of the nation's aviation system. The results from this project will provide government and industry leaders with additional tools and information to make effective decisions with respect to investments in space weather research and services. While space weather can impact the entire aviation industry, and this project will address national and international issues, the primary focus will be on developing a U.S. perspective for the airlines.

  6. A statistical model for road surface friction forecasting applying optical road weather measurements

    NASA Astrophysics Data System (ADS)

    Hippi, M.; Juga, I.; Nurmi, P.

    2009-09-01

    Road surface friction is defined as the grip between car tyre and underlying surface. Poor friction often plays a crucial role in wintertime car accidents. Friction can decrease dramatically during snowfall or when wet road surface temperature falls below zero. Even a thin layer of ice or snow can decrease friction substantially increasing the risk of accidents. Many studies have shown that road surface temperature, road conditions and friction can fluctuate dramatically within short distances under specific weather situations. Friction or grip can be improved with road maintenance activities like salting and gritting. Salting will melt the ice or snow layer, whereas gritting will improve the grip. Salting is effective only above -5C temperatures. Light snowfall together with low temperatures can result in very slippery driving conditions. Finnish Road Administration's observing network covers c. 500 road weather stations in Finland. Almost 100 of them are equipped with optical sensors (in winter 2008-2009). The number of optical sensors has increased remarkably during past few years. The optical measuring devices are Vaisala DSC111 sensors which measure the depth of water, snow and ice on the road surface and also produce an estimate of the state of road and prevailing friction. Observation data from road weather stations with optical sensors were collected from winter 2007/08, and a couple of representative (from a weather perspective) stations were selected for detailed statistical analysis. The purpose of the study was to find a statistical relationship between the observed values and, especially, the correlation between friction and other road weather parameters. Consequently, a model based on linear regression was developed. With the model friction being the dependent variable, the independent variables having highest correlations were the composite of ice and snow (water content) on the road, and the road surface temperature. In the case of a wet road

  7. Evaluation of Weather Research and Forecasting Model Predictions Using Micrometeorological Tower Observations

    NASA Astrophysics Data System (ADS)

    Kumar, Prashant; Bhattacharya, Bimal K.; Pal, P. K.

    2015-11-01

    Here we assess the predictive skill of short-range weather forecasts from the Weather Research and Forecasting (WRF) model with the help of micrometeorological tower observations. WRF model forecasts at a 3-h temporal resolution and 5000-m spatial resolution are compared with ground observations collected at micrometeorological towers during the year 2011 over the Indian landmass. Results show good agreement between the WRF model forecast and tower observed surface temperature and relative humidity, 10-m wind speed, and surface pressure. The WRF model simulations of surface energy fluxes, such as incoming shortwave, longwave radiation, and ground heat flux are also compared with micrometeorological tower measurements. Relatively high errors in incoming shortwave radiation flux may be attributed to the lack of accurate cloud prediction and the non-inclusion of aerosol load. The cyclic pattern of errors in surface relative humidity is found to be tightly and oppositely coupled with the incoming longwave radiation flux. Errors in soil heat fluxes during daytime hours are dominated by errors in the incoming shortwave radiation flux.

  8. Solar wind interaction with the Reiner Gamma crustal magnetic anomaly: Connecting source magnetization to surface weathering

    NASA Astrophysics Data System (ADS)

    Poppe, Andrew R.; Fatemi, Shahab; Garrick-Bethell, Ian; Hemingway, Doug; Holmström, Mats

    2016-03-01

    Remanent magnetization has long been known to exist in the lunar crust, yet both the detailed topology and ultimate origin(s) of these fields remains uncertain. Some crustal magnetic fields coincide with surface albedo anomalies, known as lunar swirls, which are thought to be formed by differential surface weathering of the regolith underlying crustal fields due to deflection of incident solar wind protons. Here, we present results from a three-dimensional, self-consistent, plasma hybrid model of the solar wind interaction with two different possible source magnetizations for the Reiner Gamma anomaly. We characterize the plasma interaction with these fields and the resulting spatial distribution of charged-particle weathering of the surface and compare these results to optical albedo measurements of Reiner Gamma. The model results constrain the proposed source magnetizations for Reiner Gamma and suggest that vertical crustal magnetic fields are required to produce the observed "dark lanes."

  9. Tropical Ocean Surface Energy Balance Variability: Linking Weather to Climate Scales

    NASA Technical Reports Server (NTRS)

    Roberts, J. Brent; Clayson, Carol Anne

    2013-01-01

    Radiative and turbulent surface exchanges of heat and moisture across the atmosphere-ocean interface are fundamental components of the Earth s energy and water balance. Characterizing the spatiotemporal variability of these exchanges of heat and moisture is critical to understanding the global water and energy cycle variations, quantifying atmosphere-ocean feedbacks, and improving model predictability. These fluxes are integral components to tropical ocean-atmosphere variability; they can drive ocean mixed layer variations and modify the atmospheric boundary layer properties including moist static stability, thereby influencing larger-scale tropical dynamics. Non-parametric cluster-based classification of atmospheric and ocean surface properties has shown an ability to identify coherent weather regimes, each typically associated with similar properties and processes. Using satellite-based observational radiative and turbulent energy flux products, this study investigates the relationship between these weather states and surface energy processes within the context of tropical climate variability. Investigations of surface energy variations accompanying intraseasonal and interannual tropical variability often use composite-based analyses of the mean quantities of interest. Here, a similar compositing technique is employed, but the focus is on the distribution of the heat and moisture fluxes within their weather regimes. Are the observed changes in surface energy components dominated by changes in the frequency of the weather regimes or through changes in the associated fluxes within those regimes? It is this question that the presented work intends to address. The distribution of the surface heat and moisture fluxes is evaluated for both normal and non-normal states. By examining both phases of the climatic oscillations, the symmetry of energy and water cycle responses are considered.

  10. Surface roughness and color characteristics of wood treated with preservatives after accelerated weathering test

    NASA Astrophysics Data System (ADS)

    Temiz, Ali; Yildiz, Umit C.; Aydin, Ismail; Eikenes, Morten; Alfredsen, Gry; Çolakoglu, Gürsel

    2005-08-01

    Wood samples treated with ammonium copper quat (ACQ 1900 and ACQ 2200), chromated copper arsenate (CCA), Tanalith E 3491 and Wolmanit CX-8 have been studied in accelerated weathering experiments. The weathering experiment was performed by cycles of 2 h UV-light irradiation followed by water spray for 18 min. The changes on the surface of the weathered samples were characterized by roughness and color measurements on the samples with 0, 200, 400 and 600 h of total weathering. The objective of this study was to investigate the changes created by weathering on impregnated wood with several different wood preservatives. This study was performed on the accelerated weathering test cycle, using UV irradiation and water spray in order to simulate natural weathering. Surface roughness and color measurement was used to investigate the changes after several intervals (0-200-400-600 h) in artificial weathering of treated and untreated wood.

  11. Development of a Graphical User Interface to Visualize Surface Observations

    SciTech Connect

    Buckley, R.L.

    1998-07-13

    Thousands of worldwide observing stations provide meteorological information near the earth's surface as often as once each hour. This surface data may be plotted on geographical maps to provide the meteorologist useful information regarding weather patterns for a region of interest. This report describes the components and applications of a graphical user interface which have been developed to visualize surface observations at any global location and time of interest.

  12. Chitinophaga qingshengii sp. nov., isolated from weathered rock surface.

    PubMed

    Cheng, Cheng; Wang, Qi; He, Lin-Yan; Huang, Zhi; Sheng, Xia-Fang

    2015-01-01

    A novel mineral-weathering bacterium was isolated from weathered rock (potassic trachyte) surfaces collected from Nanjing (Jiangsu, PR China). Cells of strain JN246(T) were Gram-stain-negative, rod-shaped and non-motile. Strain JN246(T) was aerobic, catalase- and oxidase-positive, and grew optimally at 28 °C and pH 7.0. On the basis of 16S rRNA gene sequence analysis, strain JN246(T) belonged to the genus Chitinophaga and the closest phylogenetic relatives were Chitinophaga eiseniae YC6729(T) (98.5% 16S rRNA gene sequence similarity), Chitinophaga terrae KP01(T) (96.8%), and Chitinophaga jiangningensis JN53(T) (96.3 %). The major respiratory quinone was MK-7 and the major polyamine was homospermidine. The major fatty acids were iso-C15:0, C16:1ω5c, C16:0 and iso-C17:0 3-OH. The polar lipid profile of strain JN246(T) consisted of phosphatidylethanolamine, unknown aminolipids and unknown lipids. The genomic DNA G+C content of strain JN246(T) was 48.8 mol%. Based on the low level of DNA-DNA relatedness of strain JN246(T) (ranging from 22.6% to 42.4%) to the type strains of other species of the genus Chitinophaga and unique phenotypic characteristics, strain JN246(T) represents a novel species of the genus Chitinophaga, for which the name Chitinophaga qingshengii sp. nov. is proposed. The type strain is JN246(T) ( = CCTCC AB 2014201(T) = JCM 30026(T)). PMID:25342110

  13. Toward Application of Lightning Observations to Weather Forecasts and Warnings

    NASA Astrophysics Data System (ADS)

    Macgorman, D. R.

    2002-12-01

    Once lightning mapping systems became fast enough to locate lightning in real or near-real time, it became possible to consider applications of lightning data to weather operations. The first system to be used routinely in such a way was the LLP direction-finder network deployed around 1980 by the Bureau of Land Management to help detect range and forest fires started by cloud-to-ground lightning. In 1987, a federal interagency group collaborated with the State University of New York at Albany to put together a trial National Lightning Detection Network for a three-year evaluation of possible applications to weather operations. During this trial, the National Weather Service determined that the lightning ground-strike data are useful for detecting the presence, configuration, and evolution of storms and storm systems, and so subsequently procured lightning strike mapping data for federal use that has continued to the present. Research since then has suggested that detection of positive cloud-to-ground lightning may also be useful, when combined with radar data, to help identify some severe storms, though the conditions under which this is possible are still being investigated. Furthermore, cloud-to-ground flash data can be assimilated into forecast models to improve the initial conditions, and hence the forecasts, of the models. More recently technology has advanced to the point that mapping all types of lightning is feasible. Because typically more than 70% of the lightning flashes produced by a storm do not strike ground, such technologies, at a minimum, would increase sampling rates to identify thunderstorms more quickly and reliably. However, different types of lightning also provide different information about storms. Cloud-to-ground lightning tends to indicate the formation and descent of precipitation, while cloud flash rates appear to be associated more closely with updraft and graupel evolution. Research is underway to determine and quantify these

  14. Space Weather Monitoring for ISS Space Environments Engineering and Crew Auroral Observations

    NASA Technical Reports Server (NTRS)

    Minow, Joseph; Pettit, Donald R.; Hartman, William A.

    2012-01-01

    Today s presentation describes how real time space weather data is used by the International Space Station (ISS) space environments team to obtain data on auroral charging of the ISS vehicle and support ISS crew efforts to obtain auroral images from orbit. Topics covered include: Floating Potential Measurement Unit (FPMU), . Auroral charging of ISS, . Real ]time space weather monitoring resources, . Examples of ISS auroral charging captured from space weather events, . ISS crew observations of aurora.

  15. Titan's rotation - Surface feature observed

    NASA Astrophysics Data System (ADS)

    Lemmon, M. T.; Karkoschka, E.; Tomasko, M.

    1993-06-01

    A surface feature or a near-surface fracture is suggested to account for the time variations in the 0.94, 1.08, and 1.28 micron atmospheric windows of Titan's geometric albedo, relative to its albedo in adjacent methane bands. These observations are noted to be consistent with synchronous rotation. They can also be explained by a 0.1-higher surface albedo on Titan's leading hemisphere.

  16. Training Guide in Surface SAWRS Observations.

    ERIC Educational Resources Information Center

    National Oceanic and Atmospheric Administration (DOC), Rockville, MD. National Weather Service.

    As a replacement of the 1949 primary training manual for supplementary aeronautical weather reports, instructions are presented in this Training Paper No. 5 for the purpose of guiding learners through their study of the Weather Service Observing Handbook (WSOH) No. 4. The content is divided into six chapters concerned with such topics as…

  17. Space Weathering Impact on Solar System Surfaces and Planetary Mission Science

    NASA Technical Reports Server (NTRS)

    Cooper, John F.

    2011-01-01

    We often look "through a glass, darkly" at solar system bodies with tenuous atmospheres and direct surface exposure to the local space environment. Space weathering exposure acts via universal space-surface interaction processes to produce a thin patina of outer material covering, potentially obscuring endogenic surface materials of greatest interest for understanding origins and interior evolution. Examples of obscuring exogenic layers are radiation crusts on cometary nuclei and iogenic components of sulfate hydrate deposits on the trailing hemisphere of Europa. Weathering processes include plasma ion implantation into surfaces, sputtering by charged particles and solar ultraviolet photons, photolytic chemistry driven by UV irradiation, and radiolytic chemistry evolving from products of charged particle irradiation. Regolith structure from impacts, and underlying deeper structures from internal evolution, affects efficacy of certain surface interactions, e.g. sputtering as affected by porosity and surface irradiation dosage as partly attenuated by local topographic shielding. These processes should be regarded for mission science planning as potentially enabling, e.g. since direct surface sputtering, and resultant surface-bound exospheres, can provide in-situ samples of surface composition to ion and neutral mass spectrometers on orbital spacecraft. Sample return for highest sensitivity compOSitional and structural analyses at Earth will usually be precluded by limited range of surface sampling, long times for return, and high cost. Targeted advancements in instrument technology would be more cost efficient for local remote and in-situ sample analysis. More realistic laboratory simulations, e.g. for bulk samples, are needed to interpret mission science observations of weathered surfaces. Space environment effects on mission spacecraft and science operations must also be specified and mitigated from the hourly to monthly changes in space weather and from longer

  18. Space Weathering Impact on Solar System Surfaces and Planetary Mission Science

    NASA Astrophysics Data System (ADS)

    Cooper, J. F.; Hartle, R. E.; Sittler, E. C.; McGrath, M. A.; Alexander, C. J.; Dalton, J. B.; Pascu, D.; Paranicas, C.; Hibbitts, C.; Hill, M. E.; Cooper, P. D.; Johnson, R. E.; Cassidy, T. A.; Orlando, T. M.; Lanzerotti, L. J.; Schwadron, N. A.; Retherford, K. D.; Kaiser, R. I.; Leblanc, F.; Sturner, S. J.; Killen, R. M.

    2009-12-01

    We often look “through a glass, darkly” at solar system bodies with tenuous atmospheres and direct surface exposure to the local space environment. Space weathering exposure acts via universal space-surface interaction processes to produce a thin patina of outer material covering, potentially obscuring endogenic surface materials of greatest interest for understanding origins and interior evolution. Examples of obscuring exogenic layers are radiation crusts on cometary nuclei and iogenic components of sulfate hydrate deposits on the trailing hemisphere of Europa. Weathering processes include plasma ion implantation into surfaces, sputtering by charged particles and solar ultraviolet photons, photolytic chemistry driven by UV irradiation, and radiolytic chemistry evolving from products of charged particle irradiation. Regolith structure from impacts, and underlying deeper structures from internal evolution, affects efficacy of certain surface interactions, e.g. sputtering as affected by porosity and surface irradiation dosage as partly attenuated by local topographic shielding. These processes should be regarded for mission science planning as potentially enabling, e.g. since direct surface sputtering, and resultant surface-bound exospheres, can provide in-situ samples of surface composition to ion and neutral mass spectrometers on orbital spacecraft. Sample return for highest sensitivity compositional and structural analyses at Earth will usually be precluded by limited range of surface sampling, long times for return, and high cost. Targeted advancements in instrument technology would be more cost efficient for local remote and in-situ sample analysis. More realistic laboratory simulations, e.g. for bulk samples, are needed to interpret mission science observations of weathered surfaces. Space environment effects on mission spacecraft and science operations must also be specified and mitigated from the hourly to monthly changes in space weather and from longer

  19. Comparing the simulation of climate impacts on crop yields with observed and synthetic weather data

    NASA Astrophysics Data System (ADS)

    Qian, B.; de Jong, R.; Yang, J.; Wang, H.; Gameda, S.

    2010-12-01

    Stochastic weather generators have been used extensively in the development of climate scenarios, especially at the daily or shorter time scales, for the use as climate input to agricultural simulation models that evaluate the climate impacts on crop yields. Because generated synthetic weather data mimic the observed weather data, discrepancies between the two datasets often exist. For example, interannual variability in the synthetic data is often found to be weaker than in the observed data, i.e., the well-known overdispersion problem. Therefore, it is important to evaluate if the climate impact models are sensitive to such discrepancies between synthetic weather data and observed ones. In this study, we used a stochastic weather generator (AAFC-WG) to generate 300-yr long synthetic weather data for two Canadian sites (Swift Current on the Canadian Prairies and London in southern Ontario), based on the observed weather data for the baseline period of 1961-1990. The Decision Support System for Agrotechnology Transfer (DSSAT) v4.0 was employed to simulate crop growth and yield. Spring wheat at Swift Current and grain corn at London were simulated by the DSSAT cropping system model with three major soil types at each location, using the 30-yr observed weather data and 300-yr synthetic data, respectively. Statistical tests were performed to investigate whether differences (both mean and variance) of the simulated crop yields between the simulations with observed and synthetic weather data are statistically significant or not. Results demonstrated that the differences in simulated crop yields are often not statistically significant when synthetic weather data are used to substitute the observed data.

  20. Spectral properties of Titan's impact craters imply chemical weathering of its surface

    NASA Astrophysics Data System (ADS)

    Neish, C. D.; Barnes, J. W.; Sotin, C.; MacKenzie, S.; Soderblom, J. M.; Le Mouélic, S.; Kirk, R. L.; Stiles, B. W.; Malaska, M. J.; Le Gall, A.; Brown, R. H.; Baines, K. H.; Buratti, B.; Clark, R. N.; Nicholson, P. D.

    2015-05-01

    We examined the spectral properties of a selection of Titan's impact craters that represent a range of degradation states. The most degraded craters have rims and ejecta blankets with spectral characteristics that suggest that they are more enriched in water ice than the rims and ejecta blankets of the freshest craters on Titan. The progression is consistent with the chemical weathering of Titan's surface. We propose an evolutionary sequence such that Titan's craters expose an intimate mixture of water ice and organic materials, and chemical weathering by methane rainfall removes the soluble organic materials, leaving the insoluble organics and water ice behind. These observations support the idea that fluvial processes are active in Titan's equatorial regions.

  1. Exploring the Terrestrial Ecosystem Response to Extreme Weather Events using Multiple Land Surface Models

    NASA Astrophysics Data System (ADS)

    Xu, L.; Schlosser, C. A.; Kicklighter, D. W.; Felzer, B. S.; Monier, E.; Paw U, K.

    2012-12-01

    This study investigates the complex terrestrial ecosystems response to extreme weather events using three different land surface models. Previous studies have showed that extreme weather events can have serious and damaging impacts on human and natural systems and they are most evident on regional and local scales. Under climate change, extreme weather events are likely to increase in both magnitude and frequency, making realistic simulation of ecosystems response to extreme events more essential than ever in assessing the potential damaging impacts. Three different land surface models are used to explore the impacts of extreme events on regional to continental ecosystem responses. The Terrestrial Ecosystem Model (TEM) is a process-based ecosystem model that uses spatially referenced information on climate, elevation, soils, vegetation and water availability to make monthly estimates of vegetation and soil carbon and nitrogen fluxes and pool sizes. The Advanced Canopy-Atmosphere-Soil Algorithm (ACASA) is a multi-layered land surface model based on eddy-covariance theory to calculate the biosphere-atmosphere exchanges of carbon dioxide, water, and momentums. The Community Land Model (CLM) is a community-based model widely used in global-scale land data assimilation research. The study focuses on the complex interactions and feedbacks between the terrestrial ecosystem and the atmosphere such as water cycle, carbon and nitrogen budgets, and environmental conditions. The model simulations and performances are evaluated using the biogeophysical and micrometeorological observation data from the AmeriFlux sites across the continental US. This study compares and evaluates the ability of different models and their key components to capture terrestrial response to extreme weather events.

  2. Impact of various observing systems on weather analysis and forecast over the Indian region

    NASA Astrophysics Data System (ADS)

    Singh, Randhir; Ojha, Satya P.; Kishtawal, C. M.; Pal, P. K.

    2014-09-01

    To investigate the potential impact of various types of data on weather forecast over the Indian region, a set of data-denial experiments spanning the entire month of July 2012 is executed using the Weather Research and Forecasting (WRF) model and its three-dimensional variational (3DVAR) data assimilation system. The experiments are designed to allow the assessment of mass versus wind observations and terrestrial versus space-based instruments, to evaluate the relative importance of the classes of conventional instrument such as radiosonde, and finally to investigate the role of individual spaceborne instruments. The moist total energy norm is used for validation and forecast skill assessment. The results show that the contribution of wind observations toward error reduction is larger than mass observations in the short range (48 h) forecast. Terrestrial-based observations generally contribute more than space-based observations except for the moisture fields, where the role of the space-based instruments becomes more prevalent. Only about 50% of individual instruments are found to be beneficial in this experiment configuration, with the most important role played by radiosondes. Thereafter, Meteosat Atmospheric Motion Vectors (AMVs) (only for short range forecast) and Special Sensor Microwave Imager (SSM/I) are second and third, followed by surface observations, Sounder for Probing Vertical Profiles of Humidity (SAPHIR) radiances and pilot observations. Results of the additional experiments of comparative performance of SSM/I total precipitable water (TPW), Microwave Humidity Sounder (MHS), and SAPHIR radiances indicate that SSM/I is the most important instrument followed by SAPHIR and MHS for improving the quality of the forecast over the Indian region. Further, the impact of single SAPHIR instrument (onboard Megha-Tropiques) is significantly larger compared to three MHS instruments (onboard NOAA-18/19 and MetOp-A).

  3. Weather and climate analyses using improved global water vapor observations

    NASA Astrophysics Data System (ADS)

    Vonder Haar, Thomas H.; Bytheway, Janice L.; Forsythe, John M.

    2012-08-01

    The NASA Water Vapor Project (NVAP) dataset is a global (land and ocean) water vapor dataset created by merging multiple sources of atmospheric water vapor to form a global data base of total and layered precipitable water vapor. Under the NASA Making Earth Science Data Records for Research Environments (MEaSUREs) program, NVAP is being reprocessed and extended, increasing its 14-year coverage to include 22 years of data. The NVAP-MEaSUREs (NVAP-M) dataset is geared towards varied user needs, and biases in the original dataset caused by algorithm and input changes were removed. This is accomplished by relying on peer reviewed algorithms and producing the data in multiple “streams” to create products geared towards studies of both climate and weather. We briefly discuss the need for reprocessing and extension, steps taken to improve the product, and provide some early science results highlighting the improvements and potential scientific uses of NVAP-M.

  4. Mercury's Weather-Beaten Surface: Understanding Mercury in the Context of Lunar and Asteroid Space Weathering Studies

    NASA Technical Reports Server (NTRS)

    Dominque, Deborah L.; Chapman, Clark R.; Killen, Rosemary M.; Zurbuchen, Thomas H.; Gilbert, Jason A.; Sarantos, Menelaos; Benna, Mehdi; Slavin, James A.; Orlando, Thomas M.; Schriver, David; Sprague, Ann L.; Blewett, David T.; Gillis-Davis, Jeffrey J.; Feldman, William C.; Lawrence, David J.; Ho, George C.; Vilas, Faith; Pieters, Carle M.; McClintock, William E.; Helbert, Jorn

    2011-01-01

    Understanding the composition of Mercury's crust is key to comprehending the formation of the planet. The regolith, derived from the crustal bedrock, has been altered via a set of space weathering processes. These processes are the same set of mechanisms that work to form Mercury's exosphere, and are moderated by the local space environment and the presence of an intrinsic planetary magnetic field. The alterations need to be understood in order to determine the initial crustal compositions. The complex interrelationships between Mercury's exospheric processes, the space environment, and surface composition are examined and reviewed. The processes are examined in the context of our understanding of these same processes on the lunar and asteroid regoliths. Keywords: Mercury (planet) Space weathering Surface processes Exosphere Surface composition Space environment 3

  5. Seasonal changes in Titan's weather and surface features

    NASA Astrophysics Data System (ADS)

    Turtle, E. P.; Perry, J. E.; McEwen, A. S.; Barbara, J.; Del Genio, A.; West, R. A.; Hayes, A.; Schaller, E.

    2010-04-01

    Since Cassini's arrival at Saturn, the Titan's season has progressed from southern summer to just past the southern autumnal equinox (the equivalent of 12 January to 26 March), and accompanying changes in meteorology have been observed. Through 2004, large convective cloud systems were common over Titan's South Pole (e.g., Schaller et al., 2006); since 2005 such storms have been less common. Elongated streaks of clouds have been observed consistently at mid-southern latitudes, and became common at high northern latitudes in 2007. Only recently have clouds been detected at mid-northern latitudes. Changes have also been observed in surface features at high southern latitudes. A large dark area appeared between July 2004 and June 2005 (Turtle et al., 2009), and may have subsequently faded. Recent observations of Ontario Lacus suggest that its shoreline may have receded (e.g., Hayes et al., 2009). No changes have been observed to date in lakes and seas at high northern latitudes. Intriguingly, Cassini RADAR observations of Titan's South Pole reveal far fewer lakes than have been identified in the north (Stofan et al., 2007) and fewer than suggested by the number of dark features observed by ISS in this area (Turtle et al., 2009). This apparent discrepancy may indicate that not all of the dark south-polar features identified by ISS are filled with liquid. Alternatively, some lakes may be ephemeral: differences may be the result of precipitation and ponding of liquid methane and subsequent evaporation or infiltration thereof (Turtle et al., 2009) in the time between observations: ISS in mid-2004 and mid-2005 (equivalent of ~12 and ~25 January) and the RADAR observations starting in late 2007 (equivalent of ~28 February). We will present observations of Titan's meteorology and surface features, documenting seasonal changes and their implications for Titan's active methane cycle and atmospheric circulation.

  6. Ground-based observations of the fair weather vertical current response to solar disturbances

    NASA Astrophysics Data System (ADS)

    Elhalal, G.; Yair, Y.; Harrison, R.; Nicoll, K.; Price, C. G.; Yaniv, R.

    2013-12-01

    The Global atmospheric Electric Circuit (GEC) is a conceptual model that represents the observed variable and quasi-static electrical properties of the atmosphere in the Earth-ionosphere cavity. The DC component of the GEC is typified by an average potential difference of 250 kV between the upper and lower conducting layers of the surface and ionosphere, leading to a near-surface electric field (Ez) of potential gradient ~130 V m-1, and a steady downward-flowing fair-weather current density (Jz) of ~2 pA m-2. By separation the steady global circuit current from short-term fluctuations, Jz provides information on local and global conductivity changes due to aerosols, air-pollution and solar activity. This talk will present evidence for the effects of geomagnetic storms and sub-storms on the fair weather vertical current, based on results from continuous measurements of Jz conducted at the Wise Observatory in Mitzpe-Ramon, Israel (30°35'N, 34°45'E) with the GDACCS instrument (Bennett and Harrison, 2008). We studied 3 coronal mass ejections (CMEs), which included solar proton events (SPE) on 26.09.11, 24.10.11 and 08.03.12. In all three events, fluctuations in Jz increased by an order of magnitude compared to normal fair weather conditions. The dynamic spectrum of the increased fluctuations exhibit peaks in the Pc5 frequency range. Similar low frequency characteristics occur during periods of enhanced solar wind proton density. During the 24.10.11 event, the periods of increased fluctuations in Jz lasted for 7 hours and coincided with fluctuations of the inter-planetary magnetic field (IMF) that were detected by the ACE satellite. The observed current density fluctuations occurred at a period when Bz<0 and when it was highly variable, suggesting the possibility for magnetic reconnection with ensuing changes in ionospheric properties. These low-latitude observations probably represent a response of the GEC to the solar induced geomagnetic sub-storms, perhaps arising

  7. Martian Weathering Environments of the Amazonian Indicated by Correlated Morphologic and Spectral Observation in Acidalia Planitia

    NASA Astrophysics Data System (ADS)

    Kraft, M. D.; Rogers, D.; Fergason, R. L.; Michalski, J. R.; Sharp, T. G.

    2009-12-01

    While much attention has been given to chemical alteration and the state of water on early Mars, it remains important to understand aqueous processes throughout Martian history, including the recent geologic past. It has been suggested that the Amazonian was marked primarily by anhydrous, oxidative weathering because Amazonian surfaces, such as the northern plains, lack hydration features in near-infrared spectra [1]. But high-silica materials (Surface Type 2, ST2) discovered by the Thermal Emission Spectrometer [2] that occur in the northern plains attest to aqueous alteration of silicate minerals. The questions are when did this occur and by what process? ST2 correlates spatially with outflow sediments and high-silica materials may have formed in large amounts of water related to outflow flooding events of the late Hesperian [3,4]. ST2 also may correspond to global ice-rich mantles, indicating formation in icy environments related to geologically recent climate fluctuations [3]. Can these very different mechanisms and environments be discerned? In a global study of TES spectra, Rogers et al. (2007) [5] found significant spectral differences between ST2 surfaces in northern and southern Acidalia Planitia that occur near 40-50° N. Several geomorphic transitions occur across latitudes, and many of these are directly or potentially related to Amazonian periglacial activity and occur in the 40-50° N range. This potential link between composition and periglacial morphology needs further exploration. We examined this relationship from 40-50° N in Acidalia Planitia, using Thermal Emission Imaging System (THEMIS) multispectral data to measure the local spectral properties of the surface. We identified a boundary between two surface spectral types that match closely the spectra of north and south Acidalia derived by Rogers et al. [2007]. This boundary is diffuse, occurring between 47-48° N in our study region in western Acidalia, and correlates with observed

  8. Surface Exposure Ages of Space-Weathered Grains from Asteroid 25143 Itokawa

    NASA Technical Reports Server (NTRS)

    Keller, L. P.; Berger, E. L.; Christoffersen, R.

    2015-01-01

    Space weathering processes such as solar wind ion irradiation and micrometeorite impacts are widely known to alter the properties of regolith materials exposed on airless bodies. The rates of space weathering processes however, are poorly constrained for asteroid regoliths, with recent estimates ranging over many orders of magnitude. The return of surface samples by JAXA's Hayabusa mission to asteroid 25143 Itokawa, and their laboratory analysis provides "ground truth" to anchor the timescales for space weathering processes on airless bodies.

  9. Federal Cooperation toward a Nationwide Network of Weather and Climate Observing Networks

    NASA Astrophysics Data System (ADS)

    Stailey, J. E.

    2011-12-01

    Weather observing in the US has expanded well beyond its original scope, when it was largely the province of the Federal government. Much of today's observational data is collected by individuals or organizations outside the Federal domain. Application of all weather observations from across the enterprise would be useful in a variety of weather-related disciplines. However, many of those observations are not available or are not used because their quality is suspect or unknown to potential users. A broadly accepted and adopted system of standards to facilitate discovery, access, and selection of acceptable weather observations is needed to fully exploit the wealth of data being collected. Because of its still substantial role in taking and collecting weather observations, it is assumed that a system of standards employed by the Federal government would provide a strong basis for an enterprise-wide system. However, such a system, based on Federal requirements with due consideration of broader needs, does not exist. The effort to establish standards is a first step in a more comprehensive process of recognizing needs for mesoscale observations for a variety of applications, making all current observations-regardless of source-available to meet those needs, and planning for deployment of additional observing capability to fill the gaps. In response to the National Academy of Sciences report Observing Weather and Climate from the Ground Up-a Nationwide Network of Networks, the Office of the Federal Coordinator for Meteorology is working in conjunction with the American Meteorological Society and the National Earth Observation Task Force to address the challenges of building a weather observing and data management capability that meets the needs of a growing community of interest.

  10. Weather Information System

    NASA Technical Reports Server (NTRS)

    1995-01-01

    WxLink is an aviation weather system based on advanced airborne sensors, precise positioning available from the satellite-based Global Positioning System, cockpit graphics and a low-cost datalink. It is a two-way system that uplinks weather information to the aircraft and downlinks automatic pilot reports of weather conditions aloft. Manufactured by ARNAV Systems, Inc., the original technology came from Langley Research Center's cockpit weather information system, CWIN (Cockpit Weather INformation). The system creates radar maps of storms, lightning and reports of surface observations, offering improved safety, better weather monitoring and substantial fuel savings.

  11. Characterizing the process and quantifying the rate of subaerial rock weathering on desert surfaces using roughness analysis

    NASA Astrophysics Data System (ADS)

    Mushkin, Amit; Sagy, Amir; Trabelci, Eran

    2013-04-01

    Subaerial weathering of rocks is a common process observed on desert surfaces on Earth and other planetary terrestrial surfaces such as on Mars. On Earth, this weathering process has been previously identified as one of the key erosion agent driving geomorphic surface evolution and the development of desert pavements. And yet, fundamental aspects of the process, such as the relative contribution of the different weathering modes that drive it (e.g., mechanical breakdown of rocks, chemical weathering, aeolian abrasion and exfoliation) as well as the rate by which this weathering process occurs have not been systematically examined. Here, we present a new approach for quantitatively addressing these fundamental aspects of process geomorphology on desert surfaces. We focus here on co-genetic desert alluvial surfaces of different ages, i.e. alluvial chronosequences, which provide excellent recorders for the evolution of boulder-strewn surfaces into smooth desert pavements through in-situ subaerial weathering of rocks. Our approach combines independent measures of two different surface attributes: High resolution (mm-scale) 3D ground-based laser scanning (LiDAR) of surface micro-topography, and numerical dating of surface age. Roughness analysis of the LiDAR data in power spectral density (PSD) space allows us to characterize the geometric manifestation of rock weathering on the surface and to distinguish between the different weathering modes. Numerical age constraints provide independent estimates for the time elapsed since the process began. Accordingly, we are able to constrain surface roughness evolution on alluvial fan desert chronosequences through time, and present PSD analysis of surface roughness as a new quantitative tool to examine the process of subaerial rock weathering in desert environments. In this study we present results from two late Quaternary alluvial chronosequences along the Dead Sea Transform in the hyper-arid Negev desert of southern Israel. Li

  12. Correlation of the Abundance of Betaproteobacteria on Mineral Surfaces with Mineral Weathering in Forest Soils

    PubMed Central

    Lepleux, C.; Turpault, M. P.; Oger, P.; Frey-Klett, P.

    2012-01-01

    Pyrosequencing-based analysis of 16S rRNA gene sequences revealed a significant correlation between apatite dissolution and the abundance of betaproteobacteria on apatite surfaces, suggesting a role for the bacteria belonging to this phylum in mineral weathering. Notably, the cultivation-dependent approach demonstrated that the most efficient mineral-weathering bacteria belonged to the betaproteobacterial genus Burhkolderia. PMID:22798365

  13. Simulation studies of proposed observing systems and their impact on numerical weather prediction

    NASA Technical Reports Server (NTRS)

    Atlas, R.; Kalnay, E.; Susskind, J.; Baker, W. E.; Halem, M.

    1984-01-01

    A series of realistic simulation studies is being conducted as a cooperative effort between the European Centre for Medium Range Weather Forecasts (ECMWF), the National Meteorological Center (NMC), and the Goddard Laboratory for Atmospheric Sciences (GLAS) to provide a quantitative assessment of the potential impact of proposed observation systems on large scale numerical weather prediction. A special objective of this project is to avoid the unrealistic character of earlier simulation studies.

  14. Naturally weathered feldspar surfaces in the Navajo Sandstone aquifer, Black Mesa, Arizona: Electron microscopic characterization

    USGS Publications Warehouse

    Zhu, Chen; Veblen, D.R.; Blum, A.E.; Chipera, S.J.

    2006-01-01

    Naturally weathered feldspar surfaces in the Jurassic Navajo Sandstone at Black Mesa, Arizona, was characterized with high-resolution transmission and analytical electron microscope (HRTEM-AEM) and field emission gun scanning electron microscope (FEG-SEM). Here, we report the first HRTEM observation of a 10-nm thick amorphous layer on naturally weathered K-feldspar in currently slightly alkaline groundwater. The amorphous layer is probably deficient in K and enriched in Si. In addition to the amorphous layer, the feldspar surfaces are also partially coated with tightly adhered kaolin platelets. Outside of the kaolin coatings, feldspar grains are covered with a continuous 3-5 ??m thick layer of authigenic smectite, which also coats quartz and other sediment grains. Authigenic K-feldspar overgrowth and etch pits were also found on feldspar grains. These characteristics of the aged feldspar surfaces accentuate the differences in reactivity between the freshly ground feldspar powders used in laboratory experiments and feldspar grains in natural systems, and may partially contribute to the commonly observed apparent laboratory-field dissolution rate discrepancy. At Black Mesa, feldspars in the Navajo Sandstone are dissolving at ???105 times slower than laboratory rate at comparable temperature and pH under far from equilibrium condition. The tightly adhered kaolin platelets reduce the feldspar reactive surface area, and the authigenic K-feldspar overgrowth reduces the feldspar reactivity. However, the continuous smectite coating layer does not appear to constitute a diffusion barrier. The exact role of the amorphous layer on feldspar dissolution kinetics depends on the origin of the layer (leached layer versus re-precipitated silica), which is uncertain at present. However, the nanometer thin layer can be detected only with HRTEM, and thus our study raises the possibility of its wide occurrence in geological systems. Rate laws and proposed mechanisms should consider the

  15. Naturally weathered feldspar surfaces in the Navajo Sandstone aquifer, Black Mesa, Arizona: Electron microscopic characterization

    NASA Astrophysics Data System (ADS)

    Zhu, Chen; Veblen, David R.; Blum, Alex E.; Chipera, Stephen J.

    2006-09-01

    Naturally weathered feldspar surfaces in the Jurassic Navajo Sandstone at Black Mesa, Arizona, was characterized with high-resolution transmission and analytical electron microscope (HRTEM-AEM) and field emission gun scanning electron microscope (FEG-SEM). Here, we report the first HRTEM observation of a 10-nm thick amorphous layer on naturally weathered K-feldspar in currently slightly alkaline groundwater. The amorphous layer is probably deficient in K and enriched in Si. In addition to the amorphous layer, the feldspar surfaces are also partially coated with tightly adhered kaolin platelets. Outside of the kaolin coatings, feldspar grains are covered with a continuous 3-5 μm thick layer of authigenic smectite, which also coats quartz and other sediment grains. Authigenic K-feldspar overgrowth and etch pits were also found on feldspar grains. These characteristics of the aged feldspar surfaces accentuate the differences in reactivity between the freshly ground feldspar powders used in laboratory experiments and feldspar grains in natural systems, and may partially contribute to the commonly observed apparent laboratory-field dissolution rate discrepancy. At Black Mesa, feldspars in the Navajo Sandstone are dissolving at ˜10 5 times slower than laboratory rate at comparable temperature and pH under far from equilibrium condition. The tightly adhered kaolin platelets reduce the feldspar reactive surface area, and the authigenic K-feldspar overgrowth reduces the feldspar reactivity. However, the continuous smectite coating layer does not appear to constitute a diffusion barrier. The exact role of the amorphous layer on feldspar dissolution kinetics depends on the origin of the layer (leached layer versus re-precipitated silica), which is uncertain at present. However, the nanometer thin layer can be detected only with HRTEM, and thus our study raises the possibility of its wide occurrence in geological systems. Rate laws and proposed mechanisms should consider the

  16. Weather Specialist/Aerographer's Mate.

    ERIC Educational Resources Information Center

    Chanute AFB Technical Training Center, IL.

    This course trains Air Force personnel to perform duties prescribed for weather specialists and aerographer's mates. Training includes meteorology, surface and ship observation, weather radar, operation of standard weather instruments and communications equipment, and decoding and plotting of surface and upper air codes upon standard maps and…

  17. Mercury's Weather-Beaten Surface: Understanding Mercury in the Context of Lunar and Asteroidal Space Weathering Studies

    NASA Technical Reports Server (NTRS)

    Domingue, Deborah L.; Chapman, Clark. R.; Killen, Rosemary M.; Zurbuchen, Thomas H.; Gilbert, Jason A.; Sarantos, Menelaos; Benna, Mehdi; Slavin, James A.; Schriver, David; Travnicek, Pavel M.; Orlando, Thomas M.; Sprague, Ann L.; Blewett, David T.; Gillis-Davis, Jeffrey J.; Feldman, William C.; Lawrence, David J.; Ho, George C.; Ebel, Denton S.; Nittler, Larry R.; Vilas, Faith; Pieters, Carle M.; Solomon, Sean C.; Johnson, Catherine L.; Winslow, Reka M..; Helbert, Jorn; Peplowski, Patrick N.; Weider, Shoshana Z.; Mouawad, Nelly; Izenberg, Noam R.; McClintock, William E.

    2014-01-01

    Mercury's regolith, derived from the crustal bedrock, has been altered by a set of space weathering processes. Before we can interpret crustal composition, it is necessary to understand the nature of these surface alterations. The processes that space weather the surface are the same as those that form Mercury's exosphere (micrometeoroid flux and solar wind interactions) and are moderated by the local space environment and the presence of a global magnetic field. To comprehend how space weathering acts on Mercury's regolith, an understanding is needed of how contributing processes act as an interactive system. As no direct information (e.g., from returned samples) is available about how the system of space weathering affects Mercury's regolith, we use as a basis for comparison the current understanding of these same processes on lunar and asteroidal regoliths as well as laboratory simulations. These comparisons suggest that Mercury's regolith is overturned more frequently (though the characteristic surface time for a grain is unknown even relative to the lunar case), more than an order of magnitude more melt and vapor per unit time and unit area is produced by impact processes than on the Moon (creating a higher glass content via grain coatings and agglutinates), the degree of surface irradiation is comparable to or greater than that on the Moon, and photon irradiation is up to an order of magnitude greater (creating amorphous grain rims, chemically reducing the upper layers of grains to produce nanometer scale particles of metallic iron, and depleting surface grains in volatile elements and alkali metals). The processes that chemically reduce the surface and produce nanometer-scale particles on Mercury are suggested to be more effective than similar processes on the Moon. Estimated abundances of nanometer-scale particles can account for Mercury's dark surface relative to that of the Moon without requiring macroscopic grains of opaque minerals. The presence of

  18. Mercury's Weather-Beaten Surface: Understanding Mercury in the Context of Lunar and Asteroidal Space Weathering Studies

    NASA Astrophysics Data System (ADS)

    Domingue, Deborah L.; Chapman, Clark R.; Killen, Rosemary M.; Zurbuchen, Thomas H.; Gilbert, Jason A.; Sarantos, Menelaos; Benna, Mehdi; Slavin, James A.; Schriver, David; Trávníček, Pavel M.; Orlando, Thomas M.; Sprague, Ann L.; Blewett, David T.; Gillis-Davis, Jeffrey J.; Feldman, William C.; Lawrence, David J.; Ho, George C.; Ebel, Denton S.; Nittler, Larry R.; Vilas, Faith; Pieters, Carle M.; Solomon, Sean C.; Johnson, Catherine L.; Winslow, Reka M.; Helbert, Jörn; Peplowski, Patrick N.; Weider, Shoshana Z.; Mouawad, Nelly; Izenberg, Noam R.; McClintock, William E.

    2014-05-01

    Mercury's regolith, derived from the crustal bedrock, has been altered by a set of space weathering processes. Before we can interpret crustal composition, it is necessary to understand the nature of these surface alterations. The processes that space weather the surface are the same as those that form Mercury's exosphere (micrometeoroid flux and solar wind interactions) and are moderated by the local space environment and the presence of a global magnetic field. To comprehend how space weathering acts on Mercury's regolith, an understanding is needed of how contributing processes act as an interactive system. As no direct information (e.g., from returned samples) is available about how the system of space weathering affects Mercury's regolith, we use as a basis for comparison the current understanding of these same processes on lunar and asteroidal regoliths as well as laboratory simulations. These comparisons suggest that Mercury's regolith is overturned more frequently (though the characteristic surface time for a grain is unknown even relative to the lunar case), more than an order of magnitude more melt and vapor per unit time and unit area is produced by impact processes than on the Moon (creating a higher glass content via grain coatings and agglutinates), the degree of surface irradiation is comparable to or greater than that on the Moon, and photon irradiation is up to an order of magnitude greater (creating amorphous grain rims, chemically reducing the upper layers of grains to produce nanometer scale particles of metallic iron, and depleting surface grains in volatile elements and alkali metals). The processes that chemically reduce the surface and produce nanometer-scale particles on Mercury are suggested to be more effective than similar processes on the Moon. Estimated abundances of nanometer-scale particles can account for Mercury's dark surface relative to that of the Moon without requiring macroscopic grains of opaque minerals. The presence of

  19. Local topography of Mars and its relationship to surface weathering processes

    NASA Technical Reports Server (NTRS)

    Schaefer, M. W.

    1993-01-01

    There is a growing body of evidence in favor of the importance of aqueous sedimentary processes on Mars. It is important to understand the role that surface weathering processes have played in the development of the present morphology of the Martian surface. Such an understanding is important not only for its relevance to the study of volatile sources and sinks on Mars through time, but also for its relevance to Martian geologic and tectonic history. Starting in the fall of this year, the Mars Observer Laser Altimeter will begin sending back to Earth data on the topography of Mars that is of a higher quality than most of the topography data available for the Earth. This data will be invaluable, not only for understanding global and large-scale regional processes and landforms on Mars, but also for the study of local and smaller-scale regional processes and landforms. Digital topography is an important part of geologic and geomorphic studies, useful in distinguishing between different lithologies and between different types of weathering. Digital topography data may be used to study a wide variety of local and regional-scale landforms, including valleys, sand dunes, lava flows, landslides, and slopes. Topography data are also essential to the analysis of spectral response patterns, especially in areas of high topographic relief. Geomorphic classification can be significantly improved by the addition of topographic information.

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

    NASA Astrophysics Data System (ADS)

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

    2011-12-01

    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

  1. The role of SANSA's geomagnetic observation network in space weather monitoring: A review

    NASA Astrophysics Data System (ADS)

    Kotzé, P. B.; Cilliers, P. J.; Sutcliffe, P. R.

    2015-10-01

    Geomagnetic observations play a crucial role in the monitoring of space weather events. In a modern society relying on the efficient functioning of its technology network such observations are important in order to determine the potential hazard for activities and infrastructure. Until recently, it was the perception that geomagnetic storms had no or very little adverse effect on radio communication and electric power infrastructure at middle- and low-latitude regions like southern Africa. The 2003 Halloween storm changed this perception. In this paper we discuss the role of the geomagnetic observation network operated by the South African National Space Agency (SANSA) in space weather monitoring. The primary objective is to describe the geomagnetic data sets available to characterize and monitor the various types of solar-driven disturbances, with the aim to better understand the physics of these processes in the near-Earth space environment and to provide relevant space weather monitoring and prediction.

  2. INDICATION OF INSENSITIVITY OF PLANETARY WEATHERING BEHAVIOR AND HABITABLE ZONE TO SURFACE LAND FRACTION

    SciTech Connect

    Abbot, Dorian S.; Ciesla, Fred J.; Cowan, Nicolas B.

    2012-09-10

    It is likely that unambiguous habitable zone terrestrial planets of unknown water content will soon be discovered. Water content helps determine surface land fraction, which influences planetary weathering behavior. This is important because the silicate-weathering feedback determines the width of the habitable zone in space and time. Here a low-order model of weathering and climate, useful for gaining qualitative understanding, is developed to examine climate evolution for planets of various land-ocean fractions. It is pointed out that, if seafloor weathering does not depend directly on surface temperature, there can be no weathering-climate feedback on a waterworld. This would dramatically narrow the habitable zone of a waterworld. Results from our model indicate that weathering behavior does not depend strongly on land fraction for partially ocean-covered planets. This is powerful because it suggests that previous habitable zone theory is robust to changes in land fraction, as long as there is some land. Finally, a mechanism is proposed for a waterworld to prevent complete water loss during a moist greenhouse through rapid weathering of exposed continents. This process is named a 'waterworld self-arrest', and it implies that waterworlds can go through a moist greenhouse stage and end up as planets like Earth with partial ocean coverage. This work stresses the importance of surface and geologic effects, in addition to the usual incident stellar flux, for habitability.

  3. Laboratory Simulations of Space Weathering of Asteroid Surfaces by Solar Wind Ions.

    NASA Astrophysics Data System (ADS)

    Miller, Kenneth A.; De Ruette, Nathalie; Harlow, George; Domingue, Deborah L.; Savin, Daniel Wolf

    2014-06-01

    Studies into the formation of the terrestrial planets rely on the analysis of asteroids and meteorites. Asteroids are solar system remnants from the planetary formation period. By characterizing their mineralogical composition we can better constrain the formation and evolution of the inner planets.Remote sensing is the primary means for studying asteroids. Sample return missions, such as Hayabusa, are complex and expensive, hence we rely on asteroid reflectance spectra to determine chemical composition. Links have been made and debated between meteorite classes and asteroid types [1, 2]. If such relationships can be confirmed, then meteorites would provide a low cost asteroid sample set for study. However, a major issue in establishing this link is the spectral differences between meteorite samples and asteroid surfaces. The most commonly invoked explanation for these differences is that the surfaces of asteroids are space weathered [2, 3]. The dominant mechanism for this weathering is believed to be solar-wind ion irradiation [2, 4, 5]. Laboratory simulations of space weathering have demonstrated changes in the general direction required to alter spectra from unweathered meteorite samples to asteroid observations [3, 6 -10], but many open questions remain and we still lack a comprehensive understanding. We propose to explore the alleged connection of ordinary chondrite (OC) meteorites to S-type asteroids through a series of systematic laboratory simulations of solar-wind space weathering of asteroid surface materials. Here we describe the issue in more detail and describe the proposed apparatus. [1] Chapman C. R. (1996) Meteorit. Planet. Sci., 31, 699-725. [2] Chapman C. R. (2004), Annu. Rev. Earth Planet. Sci., 32, 539-567. [3] Hapke B. (2001) J. Ge-ophys. Res., 106, 10039-10074. [4] Pieters C.M. et al. (2000) Meteorit. Planet. Sci., 35, 1101-1107. [5] Ver-nazza P. et al. (2009) Nature, 458, 993-995. [6] Stra-zulla G. et al. (2005) Icarus, 174, 31-35 (2005). [7

  4. A study on the integrity and authentication of weather observation data using Identity Based Encryption.

    PubMed

    Seo, Jung Woo; Lee, Sang Jin

    2016-01-01

    Weather information provides a safe working environment by contributing to the economic activity of the nation, and plays role of the prevention of natural disasters, which can cause large scaled casualties and damage of property. Especially during times of war, weather information plays a more important role than strategy, tactics and information about trends of the enemy. Also, it plays an essential role for the taking off and landing of fighter jet and the sailing of warships. If weather information, which plays a major role in national security and economy, gets misused for cyber terrorism resulting false weather information, it could be a huge threat for national security and the economy. We propose a plan to safely transmit the measured value from meteorological sensors through a meteorological telecommunication network in order to guarantee the confidentiality and integrity of the data despite cyber-attacks. Also, such a plan allows one to produce reliable weather forecasts by performing mutual authentication through authentication devices. To make sure of this, one can apply an Identity Based Signature to ensure the integrity of measured data, and transmit the encrypted weather information with mutual authentication about the authentication devices. There are merits of this research: It is not necessary to manage authentication certificates unlike the Public Key Infrastructure methodology, and it provides a powerful security measure with the capability to be realized in a small scale computing environment, such as the meteorological observation system due to the low burden on managing keys. PMID:27536509

  5. Simulation studies of the impact of advanced observing systems on numerical weather prediction

    NASA Technical Reports Server (NTRS)

    Atlas, R.; Kalnay, E.; Susskind, J.; Reuter, D.; Baker, W. E.; Halem, M.

    1984-01-01

    To study the potential impact of advanced passive sounders and lidar temperature, pressure, humidity, and wind observing systems on large-scale numerical weather prediction, a series of realistic simulation studies between the European Center for medium-range weather forecasts, the National Meteorological Center, and the Goddard Laboratory for Atmospheric Sciences is conducted. The project attempts to avoid the unrealistic character of earlier simulation studies. The previous simulation studies and real-data impact tests are reviewed and the design of the current simulation system is described. Consideration is given to the simulation of observations of space-based sounding systems.

  6. Rates of oxidative weathering on the surface of Mars

    NASA Technical Reports Server (NTRS)

    Burns, Roger G.; Fisher, Duncan S.

    1993-01-01

    A model of acid weathering is proposed for the iron-rich basalts on Mars. Aqueous oxidation of iron sulfides released SO4(2-) and H(+) ions that initiated the dissolution of basaltic ferromagnesian silicates and released Fe(2+) ions. The Fe(2+) ions eventually underwent ferrolysis reactions and produced insoluble hydrous ferric oxide phases. Measurements of the time-dependence of acid weathering reactions show that pyrrhotite is rapidly converted to pyrite plus dissolved ferrous iron, the rate of pyrite formation decreasing with rising pH and lower temperatures. On Mars, oxidation rates of dissolved Fe(2+) ions in equatorial melt-waters in contact with the atmosphere are estimated to lie in the range 0.3-3.0 ppb Fe/yr over the pH range 2 to 6. Oxidation of Fe(2+) ions is estimated to be extremely slow in brine eutectic solutions that might be present on Mars and to be negligible in the frozen regolith.

  7. Rates of oxidative weathering on the surface of Mars

    NASA Astrophysics Data System (ADS)

    Burns, R. G.; Fisher, D. S.

    1993-02-01

    A model of acid weathering is proposed for the iron-rich basalts on Mars. Aqueous oxidation of iron sulfides released SO4(2-) and H(+) ions that initiated the dissolution of basaltic ferromagnesian silicates and released Fe(2+) ions. The Fe(2+) ions eventually underwent ferrolysis reactions and produced insoluble hydrous ferric oxide phases. Measurements of the time-dependence of acid weathering reactions show that pyrrhotite is rapidly converted to pyrite plus dissolved ferrous iron, the rate of pyrite formation decreasing with rising pH and lower temperatures. On Mars, oxidation rates of dissolved Fe(2+) ions in equatorial melt-waters in contact with the atmosphere are estimated to lie in the range 0.3-3.0 ppb Fe/yr over the pH range 2 to 6. Oxidation of Fe(2+) ions is estimated to be extremely slow in brine eutectic solutions that might be present on Mars and to be negligible in the frozen regolith.

  8. Hubble Observes Surface of Titan

    NASA Technical Reports Server (NTRS)

    1994-01-01

    Scientists for the first time have made images of the surface of Saturn's giant, haze-shrouded moon, Titan. They mapped light and dark features over the surface of the satellite during nearly a complete 16-day rotation. One prominent bright area they discovered is a surface feature 2,500 miles across, about the size of the continent of Australia.

    Titan, larger than Mercury and slightly smaller than Mars, is the only body in the solar system, other than Earth, that may have oceans and rainfall on its surface, albeit oceans and rain of ethane-methane rather than water. Scientists suspect that Titan's present environment -- although colder than minus 289 degrees Fahrenheit, so cold that water ice would be as hard as granite -- might be similar to that on Earth billions of years ago, before life began pumping oxygen into the atmosphere.

    Peter H. Smith of the University of Arizona Lunar and Planetary Laboratory and his team took the images with the Hubble Space Telescope during 14 observing runs between Oct. 4 - 18. Smith announced the team's first results last week at the 26th annual meeting of the American Astronomical Society Division for Planetary Sciences in Bethesda, Md. Co-investigators on the team are Mark Lemmon, a doctoral candidate with the UA Lunar and Planetary Laboratory; John Caldwell of York University, Canada; Larry Sromovsky of the University of Wisconsin; and Michael Allison of the Goddard Institute for Space Studies, New York City.

    Titan's atmosphere, about four times as dense as Earth's atmosphere, is primarily nitrogen laced with such poisonous substances as methane and ethane. This thick, orange, hydrocarbon haze was impenetrable to cameras aboard the Pioneer and Voyager spacecraft that flew by the Saturn system in the late 1970s and early 1980s. The haze is formed as methane in the atmosphere is destroyed by sunlight. The hydrocarbons produced by this methane destruction form a smog similar to that found over large cities, but is much

  9. Hubble Observes Surface of Titan

    NASA Technical Reports Server (NTRS)

    1994-01-01

    Scientists for the first time have made images of the surface of Saturn's giant, haze-shrouded moon, Titan. They mapped light and dark features over the surface of the satellite during nearly a complete 16-day rotation. One prominent bright area they discovered is a surface feature 2,500 miles across, about the size of the continent of Australia.

    Titan, larger than Mercury and slightly smaller than Mars, is the only body in the solar system, other than Earth, that may have oceans and rainfall on its surface, albeit oceans and rain of ethane-methane rather than water. Scientists suspect that Titan's present environment -- although colder than minus 289 degrees Fahrenheit, so cold that water ice would be as hard as granite -- might be similar to that on Earth billions of years ago, before life began pumping oxygen into the atmosphere.

    Peter H. Smith of the University of Arizona Lunar and Planetary Laboratory and his team took the images with the Hubble Space Telescope during 14 observing runs between Oct. 4 - 18. Smith announced the team's first results last week at the 26th annual meeting of the American Astronomical Society Division for Planetary Sciences in Bethesda, Md. Co-investigators on the team are Mark Lemmon, a doctoral candidate with the UA Lunar and Planetary Laboratory; John Caldwell of York University, Canada; Larry Sromovsky of the University of Wisconsin; and Michael Allison of the Goddard Institute for Space Studies, New York City.

    Titan's atmosphere, about four times as dense as Earth's atmosphere, is primarily nitrogen laced with such poisonous substances as methane and ethane. This thick, orange, hydrocarbon haze was impenetrable to cameras aboard the Pioneer and Voyager spacecraft that flew by the Saturn system in the late 1970s and early 1980s. The haze is formed as methane in the atmosphere is destroyed by sunlight. The hydrocarbons produced by this methane destruction form a smog similar to that found over large cities, but is much

  10. Weather and climate needs for lidar observations from space and concepts for their realization

    NASA Technical Reports Server (NTRS)

    Atlas, D.; Korb, C. L.

    1981-01-01

    The spectrum of weather and climate needs for lidar observations from space is discussed. This paper focuses mainly on the requirements for winds, temperature, moisture, and pressure. Special emphasis is given to the need for wind observations, and it is shown that winds are required to depict realistically all atmospheric scales in the tropics and the smaller scales at higher latitudes, where both temperature and wind profiles are necessary. The need for means to estimate air-sea exchanges of sensible and latent heat also is noted. Lidar can aid here by measurement of the slope of the boundary layer. Recent theoretical feasibility studies concerning the profiling of temperature, pressure, and humidity by differential absorption lidar (DIAL) from space and expected accuracies are reviewed. Initial ground-based trials provide support for these approaches and also indicate their direct applicability to path-average temperature measurements near the surface. An alternative approach to Doppler lidar wind measurements also is presented. The concept involves the measurement of the displacement of the aerosol backscatter pattern, at constant height, between two successive scans of the same area, one ahead of the spacecraft and the other behind it, a few minutes later. Finally, an integrated space lidar system capable of measuring temperature, pressure, humidity, and winds which combines the DIAL methods with the aerosol pattern displacement concept is described briefly.

  11. Offline land surface temperature assimilation in mumerical weather prediction output

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Land surface temperature plays an important role in land surface processes, and it is a key input to physically-based retrieval algorithms of important hydrological states and fluxes, such as soil moisture and evaporation. For this reason there are many independent estimates of land surface temperat...

  12. Widespread Surface Weathering on Early Mars: possible implication on the Past Climate

    NASA Astrophysics Data System (ADS)

    Loizeau, Damien; Carter, John; Mangold, Nicolas; Poulet, François; Rossi, Angelo P.; Allemand, Pascal; Lozac'h, Loïc; Quantin, Cathy; Bibring, Jean-Pierre

    2015-04-01

    The recent discovery of widespread hydrous clays on Mars with OMEGA/Mars Express and CRISM/MRO indicates that diverse and widespread aqueous environments existed on Mars, from the surface to kilometric depths [1, 2]. The study of the past habitability and past climates of the planet requires assessing the importance of sustained surface water vs. subsurface water in its aqueous history. Vertical sequences of Al-rich clays on top of Fe/Mg-rich clays in the top tens of meters of the surface are identified on Mars [3-6] (see figure 1) and interpreted as possible weathering profiles, similar to cases of pedogenesis on Earth (e.g. [7, 8]). A global study of these clay sequences has recently been published by Carter et al. [9]. This following work presents detailed geological analysis, performed for each identified candidate, in order to constrain their age and origin. With the increasing availability of CTX and HiRISE stereoimages, we investigate the thickness of the altered sequences, the age of the altered units and the different geological contexts to further understand the weathering process(es), and their possible implication on the past climate. The types of geologic settings where the interpreted weathering profiles are observed are much varied: from basin floor to plateaus, in apparent massive rocks to finely layered rocks. Besides, the number and variety of sequences is/was likely larger. However, in term of chronology, the alteration seems to have stopped in a relatively limited period of time for the studied cases, between 3.8 and 3.6 Ga. This would point to a formation due to a global process that enabled liquid water at the surface and pedogenesis in various regions, on various terrains, from late Noachian to early Hesperian. This global process would imply regular, widely distributed ice or precipitations in large regions of Mars at that time. If weathering occurred before that time, during the early or middle Noachian, the sequences may have been erased

  13. NEXRAD Weather Radar Observations of the 2006 Augustine Volcanic Eruption Clouds

    NASA Astrophysics Data System (ADS)

    Schneider, D. J.; Scott, C.; Wood, J.; Hall, T.

    2006-12-01

    The 2006 eruption of Augustine Volcano, Alaska provided an exceptional opportunity to detect and measure explosive volcanic events and to track drifting volcanic clouds using WRS-88D (NEXRAD) weather radar data. Radar data complemented the real-time seismic monitoring by providing rapid confirmation of ash generation and cloud height. The explosive phase of the eruption consisted of thirteen discrete Vulcanian explosions from January 11 to 28, with seismic durations that ranged from one to eleven minutes. The ash columns and drifting clouds from all of the events were observed via a NEXRAD located 185 km NE of the volcano on the Kenai Peninsula (site PAHG). The radar was operated in both precipitation and clear air modes, resulting in a temporal resolution of 4.1 to 10 minutes per complete scan, respectively. Scan elevation angles for the radar beam centroid varied slightly depending upon mode of operation, but values of 0.5, 1.5, 2.5, and 3.5 degrees were typically used, corresponding to altitudes over the volcano of 3.8, 7.2, 10.5, and 13.8 km above sea level. Estimates of eruption cloud height were made by the National Weather Service (NWS) Anchorage Forecast Office using range-height indication cross-sections and radar echo tops (the altitude of the +18.5 dBZ reflectance surface). The observed cloud heights typically ranged from 7.5 to 10.5 km above sea level, with the exception of the January 17 event which briefly had an echo top of about 14 km. Most of the eruption clouds reached their maximum height in the first scan in which they were visible, suggesting an energetic and impulsive initial event, and were at lower heights in subsequent views. These height estimates may be minimum values because very fine-grained ash at the top of eruption clouds has low radar reflectance, and thus may not be observed. Height estimates were rapidly communicated to the NWS Alaska Aviation Weather Unit and the Alaska Volcano Observatory for use in hazard statements and related

  14. JPL's Real-Time Weather Processor project (RWP) metrics and observations at system completion

    NASA Technical Reports Server (NTRS)

    Loesh, Robert E.; Conover, Robert A.; Malhotra, Shan

    1990-01-01

    As an integral part of the overall upgraded National Airspace System (NAS), the objective of the Real-Time Weather Processor (RWP) project is to improve the quality of weather information and the timeliness of its dissemination to system users. To accomplish this, an RWP will be installed in each of the Center Weather Service Units (CWSUs), located in 21 of the 23 Air Route Traffic Control Centers (ARTCCs). The RWP System is a prototype system. It is planned that the software will be GFE and that production hardware will be acquired via industry competitive procurement. The ARTCC is a facility established to provide air traffic control service to aircraft operating on Instrument Flight Rules (IFR) flight plans within controlled airspace, principally during the en route phase of the flight. Covered here are requirement metrics, Software Problem Failure Reports (SPFRs), and Ada portability metrics and observations.

  15. Downscaling surface wind predictions from numerical weather prediction models in complex terrain with WindNinja

    NASA Astrophysics Data System (ADS)

    Wagenbrenner, Natalie S.; Forthofer, Jason M.; Lamb, Brian K.; Shannon, Kyle S.; Butler, Bret W.

    2016-04-01

    Wind predictions in complex terrain are important for a number of applications. Dynamic downscaling of numerical weather prediction (NWP) model winds with a high-resolution wind model is one way to obtain a wind forecast that accounts for local terrain effects, such as wind speed-up over ridges, flow channeling in valleys, flow separation around terrain obstacles, and flows induced by local surface heating and cooling. In this paper we investigate the ability of a mass-consistent wind model for downscaling near-surface wind predictions from four NWP models in complex terrain. Model predictions are compared with surface observations from a tall, isolated mountain. Downscaling improved near-surface wind forecasts under high-wind (near-neutral atmospheric stability) conditions. Results were mixed during upslope and downslope (non-neutral atmospheric stability) flow periods, although wind direction predictions generally improved with downscaling. This work constitutes evaluation of a diagnostic wind model at unprecedented high spatial resolution in terrain with topographical ruggedness approaching that of typical landscapes in the western US susceptible to wildland fire.

  16. Space weathering of asteroidal surfaces. Influence on the UV-Vis spectra

    NASA Astrophysics Data System (ADS)

    Kaňuchová, Z.; Baratta, G. A.; Garozzo, M.; Strazzulla, G.

    2010-07-01

    Context. The surfaces of airless bodies in the Solar System are continuously altered by the bombardment of micrometeoroids and irradiation by solar wind, flares, and cosmic particles. Major effects of this process - space weathering - are darkening and “reddening” of the spectra of surface materials, as well as a “degrading” of absorption features. Aims: We studied the changes induced by energetic ion irradiation in the ultraviolet-visual-near-infrared (UV-Vis-NIR) (0.2-0.98 μm) reflectance spectra of targets selected to mimic the surfaces of airless bodies in the inner Solar System. Our chosen targets are olivine pellets, pure or covered by an organic polymer (polystyrene), which is transparent before irradiation. Polystyrene is used as a template for organic matter of low volatility that can be present on asteroidal surfaces. Moreover we measured the changes induced by ion irradiation in the absorption coefficient of the polymer. The purpose was to have a tool to better compare laboratory with observed spectra and distinguish between planetary objects with pure silicate surfaces and those whose surface is covered by organic matter exposed to cosmic ion bombardment. Methods: The samples were irradiated in vacuum, at room temperature, with 200 keV protons or 200-400 keV argon ions. Before, during, and after irradiation diffuse reflectance spectra were acquired. Polystyrene films were also deposited on quartz substrates and irradiated while transmittance spectra were recorded. Results: We measured the variations of the absorption coefficient of polystyrene as a function of ion fluence. We showed that after ion irradiation the diffuse reflectance spectra of the samples covered by organics exhibit a much more significant variation than those of pure silicates. The spectra of targets made of olivine plus polystyrene can be fitted by using the measured absorption coefficient of polystyrene. Conclusions: The results obtained for pure olivine extend to the UV the

  17. Feasibility of using a seismic surface wave method to study seasonal and weather effects on shallow surface soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objective of this paper is to study the feasibility of using a seismic surface wave method to investigate seasonal and weather effects on shallow surface soils. In the study, temporal variations of subsurface soil properties were measured and monitored by using a combination of a new seismic su...

  18. Feasibility of using a seismic surface wave method to study seasonal and weather effects on shallow surface soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objective of the paper is to study the temporal variations of the subsurface soil properties due to seasonal and weather effects using a combination of a new seismic surface method and an existing acoustic probe system. A laser Doppler vibrometer (LDV) based multi-channel analysis of surface wav...

  19. Porosity and surface area evolution during weathering of two igneous rocks

    SciTech Connect

    Navarre-Sitchler, Alexis; Cole, David; Rother, Gernot; Jin, Lixin; Buss, Heather; Brantley, S. L.

    2013-01-01

    During weathering, rocks release nutrients and storewater vital for growth ofmicrobial and plant life. Thus, the growth of porosity as weathering advances into bedrock is a life-sustaining process for terrestrial ecosystems. Here, we use small-angle and ultra small-angle neutron scattering to show how porosity develops during initial weathering under tropical conditions of two igneous rock compositions, basaltic andesite and quartz diorite. The quartz diorite weathers spheroidally while the basaltic andesite does not. The weathering advance rates of the two systems also differ, perhaps due to this difference in mechanism, from 0.24 to 100 mm kyr1, respectively. The scattering data document how surfaces inside the feldspar-dominated rocks change as weathering advances into the protolith. In the unaltered rocks, neutrons scatter fromtwo types of featureswhose dimensions vary from6 nmto 40 lm: pores and bumps on pore grain surfaces. These features result in scattering data for both unaltered rocks that document multi-fractal behavior: scattering is best described by amass fractal dimension (Dm) and a surface fractal dimension (Ds) for features of length scales greater than and less than 1 lm, respectively. In the basaltic andesite, Dm is approximately 2.9 and Ds is approximately 2.7. The mechanism of solute transport during weathering of this rock is diffusion. Porosity and surface area increase from 1.5%to 8.5%and 3 to 23 m2 g1 respectively in a relatively consistent trend across themm-thick plagioclase reaction front. Across this front, both fractal dimensions decrease, consistentwith development of amoremonodisperse pore networkwith smoother pore surfaces. Both changes are consistent largely with increasing connectivity of pores without significant surface roughening, as expected for transport-limited weathering. In contrast, porosity and surface area increase from 1.3% to 9.5% and 1.5 to 13 m2 g1 respectively across a many cm-thick reaction front in the

  20. Monitoring Inland Ice Cover under All-weather Conditions with the Combined Use of Microwave and GOES-R Observations

    NASA Astrophysics Data System (ADS)

    Liu, Y.; Key, J. R.; Wang, X.

    2010-12-01

    The cryosphere exists at all latitudes and in about one hundred countries. Not only does the cryosphere play a significant role in climate, but also it has profound socio-economic value, especially over inland water, including lakes and rivers, due to its role in water resources and its impact on transportation, fisheries, hunting, herding, and agriculture. A number of ice characterization algorithms have been improved and/or developed for the next generation Geostationary Operational Environmental Satellite (GOES-R) Advanced Baseline Imager (ABI), including ice identification, ice concentration, ice thickness and age, and ice motion. These products will play an important role in monitoring ice cover over inland water considering its high spatial, temporal, and spectral resolution. However, the effectiveness of such products is constrained by cloud cover. Lake ice products from microwave observations are less affected by clouds, but their quality is hindered by coarse spatial and temporal resolution as well as contamination by the land surface. Optimization of all-weather ice products from microwave observations, and ice products with higher spatial and temporal resolutions from GOES-R enables us to monitor the ice characteristics over the inland water surfaces, e.g., the Great Lakes, effectively in real time under all-weather conditions, and improves the products that are being developed for ABI. The combined used of both products provides accurate, timely information on ice characteristics over inland water surfaces to meet the needs of transportation and winter weather forecasting. An overview of the ice cover, concentration, and motion products for both GOES-R and microwave observation will be given, and case studies of combining both products for monitoring ice characteristics over inland water will be presented.

  1. Conversion of bedrock to soil and feedback processes between the surface and the weathering front in a deeply weathered regolith, Central Sri Lankan Highlands

    NASA Astrophysics Data System (ADS)

    Behrens, Ricarda; Bouchez, Julien; Schuessler, Jan A.; Dultz, Stefan; Hewawasam, Tilak; von Blanckenburg, Friedhelm

    2014-05-01

    In the Sri Lankan highlands denudation rates and chemical weathering rates represent the low-end-member in global weathering rates [1, 2]. Here we explore the causes for these low rates by a detailed soil-mineralogical study of a highly weathered deep saprolite profile developed from charnockite bedrock. Spheroidal weathering of the bedrock characterized the weathering front where rounded corestones are produced at the rock-saprolite interface. The first mineral attacked by weathering was found to be pyroxene but plagioclase is the first mineral depleted to near-completion at the corestone-saprolite-boundary. Weathering of pyroxene is initiated by in situ iron oxidation, leading to an increase of porosity due to micro-cracking [3]. The accrued micro cracks allow for fluid transport and the dissolution of biotite and plagioclase. The strong plagioclase weathering leads to formation of high secondary porosity over a small distance and the final disaggregation of bedrock to saprolite. Sequential extraction showed that the first secondary phases are amorphous oxides from which secondary minerals (gibbsite, kaolinite, goethite and minor amounts of smectites) precipitate. Modeling of the strain formation due to increasing volume during iron oxidation in pyroxene and biotite showed that spheroidal weathering can be explained with this process only if the formation of secondary porosity, due to a negative volume budget during primary mineral weathering to secondary phases, occurs. As oxidation is the first occurring reaction, O2 is a rate limiting factor for chemical weathering in this setting. Hence the supply of oxygen and the consumption at depth connects processes at the weathering front with those at the surface as a feedback mechanism. Advective and diffusive transport modeling shows that the feedback will be much more pronounced with dominating diffusive transport. Due to the low porosity of the bedrock the O2 transport in the pristine bedrock occurs via diffusion

  2. ULF Waves Observed at MAGDAS Stations as Probes for Litho-Space Weather Study

    NASA Astrophysics Data System (ADS)

    Yumoto, Kiyohumi

    K.Yumoto, Space Environment Research Center (SERC), Kyushu University started the MAGDAS Project effectively in May of 2005, with the installation of the first unit in Hualien, Taiwan (Yumoto et al., 2006, 2007). Since then, over 50 units have been deployed around the world. They are concentrated along three chains: (1) North and South of Japan (the so-called "210o Magnetic Meridian Chain"), (2) Dip Equator Chain, and (3) Africa Chain (the so-called "96o Magnetic Meridian Chain"). The main goals of MAGDAS project are: (1) study magnetospheric pro-cesses by distinguishing between temporal changes and spatial variations in the phenomena, (2) clarify global structures and propagation characteristics of magnetospheric variations from higher to equatorial latitudes, and (3) understand global generation mechanisms of the Solar-Terrestrial phenomena (see Yumoto, 2004). From MAGDAS observations, ULF waves are found to be used as good probes for litho-space weather study in developing and developed countries. In the present paper, we will introduce the following examples: Pc 5 magnetic amplitudes at lower-latitude MAGDAS station show a linear relation with the solar wind velocity, thus we can use the Pc 5 amplitudes as a monitoring probe of the solar wind velocity. Pc 3-4 magnetic pulsations have skin depth comparable with the depth of epicentre of earthquakes in the lithosphere. Therefore, we can use Pc 3-4 as a probe for detecting ULF anomaly and precursors associated with great earthquakes. Pi 2 magnetic pulsations are observed globally at MAGDAS stations located at high, middle, low, and equatorial latitudes in night-and day-time. We can use the Pi 2s as a good indicator of onsets of magnetospheric substorms. Sudden commencements (sc), sudden impulse (si), and solar flare effects (sfe) create magnetic variations at MAGDAS stations. Therefore, MAGDAS data can be used as a probe of interplanetary shocks and interplanetary discontinuities in the solar wind, and solar flare

  3. The Main Pillar: Assessment of Space Weather Observational Asset Performance Supporting Nowcasting, Forecasting and Research to Operations

    NASA Astrophysics Data System (ADS)

    Posner, A.; Hesse, M.; St. Cyr, C.

    2012-12-01

    Sporadically, the Sun unleashes severe magnetic activity into the heliosphere. The specific solar/heliospheric phenomena and their effects on humans, technology and the wider geospace environment include a) high-intensity emissions from the Sun causing radio blackouts and (surface) charging, b) particle acceleration in the solar corona leading to high dose rates of ionizing radiation in exposed materials that can trigger single event upsets in electronic components of space hardware, or temporal/permanent damage in tissue, c) arrivals of fast-moving coronal mass ejections with embedded enhancements of magnetic fields that can cause strong ionospheric disturbances affecting radio communications and induce out-of-spec currents in power lines near the surface. Many of the effects could now be forecast with higher fidelity than ever before. However, forecasting critically depends upon availability of timely and reliable observational data. It is therefore crucial to understand how observational assets perform during periods of severe space weather. This paper analyzes and documents the status of the existing and upcoming observational capabilities for forecasting, and discusses how the findings may impact space weather research and its transition to operations.

  4. Weather impacts on space operations

    NASA Astrophysics Data System (ADS)

    Madura, J.; Boyd, B.; Bauman, W.; Wyse, N.; Adams, M.

    The efforts of the 45th Weather Squadron of the USAF to provide weather support to Patrick Air Force Base, Cape Canaveral Air Force Station, Eastern Range, and the Kennedy Space Center are discussed. Its weather support to space vehicles, particularly the Space Shuttle, includes resource protection, ground processing, launch, and Ferry Flight, as well as consultations to the Spaceflight Meteorology Group for landing forecasts. Attention is given to prelaunch processing weather, launch support weather, Shuttle launch commit criteria, and range safety weather restrictions. Upper level wind requirements are examined. The frequency of hourly surface observations with thunderstorms at the Shuttle landing facility, and lightning downtime at the Titan launch complexes are illustrated.

  5. Additional Arctic observations improve weather and sea-ice forecasts for the Northern Sea Route

    PubMed Central

    Inoue, Jun; Yamazaki, Akira; Ono, Jun; Dethloff, Klaus; Maturilli, Marion; Neuber, Roland; Edwards, Patti; Yamaguchi, Hajime

    2015-01-01

    During ice-free periods, the Northern Sea Route (NSR) could be an attractive shipping route. The decline in Arctic sea-ice extent, however, could be associated with an increase in the frequency of the causes of severe weather phenomena, and high wind-driven waves and the advection of sea ice could make ship navigation along the NSR difficult. Accurate forecasts of weather and sea ice are desirable for safe navigation, but large uncertainties exist in current forecasts, partly owing to the sparse observational network over the Arctic Ocean. Here, we show that the incorporation of additional Arctic observations improves the initial analysis and enhances the skill of weather and sea-ice forecasts, the application of which has socioeconomic benefits. Comparison of 63-member ensemble atmospheric forecasts, using different initial data sets, revealed that additional Arctic radiosonde observations were useful for predicting a persistent strong wind event. The sea-ice forecast, initialised by the wind fields that included the effects of the observations, skilfully predicted rapid wind-driven sea-ice advection along the NSR. PMID:26585690

  6. Additional Arctic observations improve weather and sea-ice forecasts for the Northern Sea Route

    NASA Astrophysics Data System (ADS)

    Inoue, Jun; Yamazaki, Akira; Ono, Jun; Dethloff, Klaus; Maturilli, Marion; Neuber, Roland; Edwards, Patti; Yamaguchi, Hajime

    2015-11-01

    During ice-free periods, the Northern Sea Route (NSR) could be an attractive shipping route. The decline in Arctic sea-ice extent, however, could be associated with an increase in the frequency of the causes of severe weather phenomena, and high wind-driven waves and the advection of sea ice could make ship navigation along the NSR difficult. Accurate forecasts of weather and sea ice are desirable for safe navigation, but large uncertainties exist in current forecasts, partly owing to the sparse observational network over the Arctic Ocean. Here, we show that the incorporation of additional Arctic observations improves the initial analysis and enhances the skill of weather and sea-ice forecasts, the application of which has socioeconomic benefits. Comparison of 63-member ensemble atmospheric forecasts, using different initial data sets, revealed that additional Arctic radiosonde observations were useful for predicting a persistent strong wind event. The sea-ice forecast, initialised by the wind fields that included the effects of the observations, skilfully predicted rapid wind-driven sea-ice advection along the NSR.

  7. Additional Arctic observations improve weather and sea-ice forecasts for the Northern Sea Route.

    PubMed

    Inoue, Jun; Yamazaki, Akira; Ono, Jun; Dethloff, Klaus; Maturilli, Marion; Neuber, Roland; Edwards, Patti; Yamaguchi, Hajime

    2015-01-01

    During ice-free periods, the Northern Sea Route (NSR) could be an attractive shipping route. The decline in Arctic sea-ice extent, however, could be associated with an increase in the frequency of the causes of severe weather phenomena, and high wind-driven waves and the advection of sea ice could make ship navigation along the NSR difficult. Accurate forecasts of weather and sea ice are desirable for safe navigation, but large uncertainties exist in current forecasts, partly owing to the sparse observational network over the Arctic Ocean. Here, we show that the incorporation of additional Arctic observations improves the initial analysis and enhances the skill of weather and sea-ice forecasts, the application of which has socioeconomic benefits. Comparison of 63-member ensemble atmospheric forecasts, using different initial data sets, revealed that additional Arctic radiosonde observations were useful for predicting a persistent strong wind event. The sea-ice forecast, initialised by the wind fields that included the effects of the observations, skilfully predicted rapid wind-driven sea-ice advection along the NSR. PMID:26585690

  8. Total Lightning Observations of Extreme Weather Events over the Contiguous United States

    NASA Technical Reports Server (NTRS)

    Carey, Lawrence D.; Petersen, Walter A.; Christian, Hugh J.

    2008-01-01

    The overall objective is to investigate total lightning characteristics of extreme weather events over the contiguous United States (CONUS) using TRMM (Tropical Rainfall Measuring Mission) LIS (Lightning Image Sensor) and OTD (Optical Transient Detector) satellite observations. A large LIS (10+ years) and OTD (5 years) data base is available to study the instantaneous total or cloud-to-ground (CG) plus intracloud (IC) lightning characteristics of extreme weather events. More specifically, the LIS and OTD data are combined with National Lightning Detection Network (NLDN) observations to examine the total and CG lightning flash rate and density, the IC:CG ratio, and positive CG percentage. These instantaneous lightning characteristics can be used for basic science studies to better understand the physical and dynamical linkages between lightning and precipitation and their environmental controls. They can also provide a first-look of extreme weather events leading up to future satellite observations (e.g., NOAA GOES-R Geostationary Lightning Mapper [GLM]) for use in climate studies and the short-term prediction and warning process. Extreme weather events are defined by the NOAA Storm Data reports of tornadoes, large hail (at least 0.75 inch) and strong straight-line winds (at least 50 kts). Over CONUS, there are over 70,000 severe storm reports in the TRMM spatial domain (< 35 N) from 1998-2007 and over 100,000 storm reports in the OTD spatial domain (5/1995-4/2000). Temporal co-location is on the order of 1% (i.e., 1000 s of coincident overpasses), providing a statistically significant sample of instantaneous total lightning properties. This instantaneous behavior of lightning in extreme weather is then compared to that of typical thunderstorm events, or randomly sampled LIS/OTD events in which the extreme events have been eliminated from the population. Results describing the instantaneous behavior of total lightning within a large sample of extreme and typical

  9. Planetary Space Weather: Long term prediction based on observations of hidden sunspot development

    NASA Astrophysics Data System (ADS)

    Schmidt, W.; Quémerais, E.; Kyrölä, E.

    2014-04-01

    Space weather phenomena at the Earth or other planets are caused by activities on the solar surface. These are accompanied by intensified Lyman alpha radiation which can be used to monitor active solar regions even when they move behind the Sun as seen from Earth. Using the Lyman alpha mapper SWAN on SOHO one can follow the development of these active regions and thereby predict their state long before they re-appear around the limb of the Sun. This information can be used to prepare for possible adverse effects on infrastructures up to 15 days before the solar wind particles start interacting with the near-Earth environment. In a similar way the space weather situation can be predicted for the environment around other planets in the Solar system.

  10. Chemical Weathering of Black Shales and Rare Earth Element Composition of Surface Waters and Groundwater

    NASA Astrophysics Data System (ADS)

    Hannigan, R. E.; Johannesson, K. H.

    2001-05-01

    Weathering processes dominate the dissolved and suspended loads of most of the world's major rivers. Among sedimentary rocks, black shales are particularly sensitive to chemical weathering. Therefore, shale systems are useful for investigating the partitioning of chemical elements during chemical weathering. Recent studies, such as those by Peucker-Ehrenbrink, Ravizza and others, link chemical weathering of black shales to changes in marine isotopic composition. Rare earth elements (REE) have a unique chemistry and are ideal for such tracer studies. We explored the effect of modern chemical weathering of black shales on the hydrochemistry of surface and groundwaters in the Mohawk Valley of New York State. This region provides an ideal site for the investigation of trace element remobilization during the chemical weathering of black shales. In this region, surface and groundwaters, in intimate contact with black shales and have high dissolved metal concentrations presumably due to water-rock interactions. The extent to which the dissolved REE composition of the surface and ground waters retains the rock signature is, in someway related to the length of time that the water remains in contact with the rock. We compared the REE compositions of surface and groundwaters in areas draining black shale to those of waters draining regions of dolostone-limestone to explore the extent of metal release due to chemical weathering. Shale normalized REE patterns for stream waters exhibit slight heavy REE enrichments and, at some locations, LREE depletion. REE patterns of the waters normalized to their respective sediments show some LREE depletion. However, waters associated with the Little Falls dolomite show fractionation predominantly enriched in the heavy REEs. Differences between the black shale sites, recorded as light REE depletion and/or middle REE enrichment, may be related to the discharge of the streams and the total dissolved solids. The dissolved REE chemistry of

  11. C3Winds: A Novel 3D Wind Observing System to Characterize Severe Weather Events

    NASA Astrophysics Data System (ADS)

    Kelly, M. A.; Wu, D. L.; Yee, J. H.; Boldt, J.; Demajistre, R.; Reynolds, E.; Tripoli, G. J.; Oman, L.; Prive, N.; Heidinger, A. K.; Wanzong, S.

    2015-12-01

    The CubeSat Constellation Cloud Winds (C3Winds) is a NASA Earth Venture Instrument (EV-I) concept with the primary objective to resolve high-resolution 3D dynamic structures of severe wind events. Rapid evolution of severe weather events highlights the need for high-resolution mesoscale wind observations. Yet mesoscale observations of severe weather dynamics are quite rare, especially over the ocean where extratropical and tropical cyclones (ETCs and TCs) can undergo explosive development. Measuring wind velocity at the mesoscale from space remains a great challenge, but is critically needed to understand and improve prediction of severe weather and tropical cyclones. Based on compact, visible/IR imagers and a mature stereoscopic technique, C3Winds has the capability to measure high-resolution (~2 km) cloud motion vectors and cloud geometric heights accurately by tracking cloud features from two formation-flying CubeSats, separated by 5-15 minutes. Complementary to lidar wind measurements from space, C3Winds will provide high-resolution wind fields needed for detailed investigations of severe wind events in occluded ETCs, rotational structures inside TC eyewalls, and ozone injections associated with tropopause folding events. Built upon mature imaging technologies and long history of stereoscopic remote sensing, C3Winds provides an innovative, cost-effective solution to global wind observations with the potential for increased diurnal sampling via CubeSat constellation.

  12. Combining solar science and asteroid science with the space weather observation network (SWON)

    NASA Astrophysics Data System (ADS)

    Maiwald, Volker; Weiß, André; Jansen, Frank

    2012-12-01

    The peculiarity of space weather for Earth orbiting satellites, air traffic and power grids on Earth and especially the financial and operational risks posed by damage due to space weather, underline the necessity of space weather observation. The importance of such observations is even more increasing due to the impending solar maximum. In recognition of this importance we propose a mission architecture for solar observation as an alternative to already published mission plans like Solar Probe (NASA) or Solar Orbiter (ESA). Based upon a Concurrent Evaluation session in the Concurrent Engineering Facility of the German Aerospace Center, we suggest using several spacecraft in an observation network. Instead of placing such spacecraft in a solar orbit, we propose landing on several asteroids, which are in opposition to Earth during the course of the mission and thus allow observation of the Sun's far side. Observation of the far side is especially advantageous as it improves the warning time with regard to solar events by about 2 weeks. Landing on Inner Earth Object (IEO) asteroids for observation of the Sun has several benefits over traditional mission architectures. Exploiting shadowing effects of the asteroids reduces thermal stress on the spacecraft, while it is possible to approach the Sun closer than with an orbiter. The closeness to the Sun improves observation quality and solar power generation, which is intended to be achieved with a solar dynamic system. Furthermore landers can execute experiments and measurements with regard to asteroid science, further increasing the scientific output of such a mission. Placing the spacecraft in a network would also benefit the communication contact times of the network and Earth. Concluding we present a first draft of a spacecraft layout, mission objectives and requirements as well as an initial mission analysis calculation.

  13. Weather Observers: A Manipulative Augmented Reality System for Weather Simulations at Home, in the Classroom, and at a Museum

    ERIC Educational Resources Information Center

    Hsiao, Hsien-Sheng; Chang, Cheng-Sian; Lin, Chien-Yu; Wang, Yau-Zng

    2016-01-01

    This study focused on how to enhance the interactivity and usefulness of augmented reality (AR) by integrating manipulative interactive tools with a real-world environment. A manipulative AR (MAR) system, which included 3D interactive models and manipulative aids, was designed and developed to teach the unit "Understanding Weather" in a…

  14. WORLD SURFACE CURRENTS FROM SHIP'S DRIFT OBSERVATIONS

    SciTech Connect

    Duncan, C.P.; Schladow, S.G.

    1980-11-01

    Over 4 million observations of ship's drift are on file at the U.S. National Oceanographic Data Centre, in Washington, D. C., representing a vast amount of information on ocean surface currents. The observed drift speeds are dependent on the frequency of occurence of the particular current speeds and the frequency of observation. By comparing frequency of observation with the drift speeds observed it is possible to confirm known current patterns and detect singularities in surface currents.

  15. Production of mineral surface area within deep weathering profiles at eroding vs. depositional hillslope locations: Christina River Basin Critical Zone Observatory

    NASA Astrophysics Data System (ADS)

    Fisher, B.; Yoo, K.; Aufdenkampe, A. K.; Nater, E.

    2014-12-01

    Geomorphic and biogeochemical processes and hillslope morphology are partly controlled by the extent and degree of chemical weathering between soil and bedrock. The production of mineral specific surface area (SSA) via chemical weathering is a critical variable for mechanistic understanding of weathering and provides an interface between minerals and the soil carbon cycle. We examined two 21-meter deep drill cores in the Laurels Schist at 141 MASL (summit) and 130 MASL (interfluve) in a 900 ha first order watershed in the Laurels Preserve, a forested land use end member in the Christina River Basin CZO. In addition to mineral SSA, we report elemental and mineralogical changes through both weathering profiles. Despite highly variable bedrock composition, mobile elements (Ca & Na) are depleted within 3-5 m below the ground surface, which is consistent with the removal of Ca-Na-plagioclase ((Na,Ca)Al(Si,Al)3O8) at this interval; we consider this depth as a weathering front. The water table in both boreholes was ~123 MASL (5/2014), which is well below the weathering front, suggesting that weathering processes are not coupled with groundwater interactions in this system. Clay XRD reveals the presence of secondary phyllosilicates including vermiculite, illite, and kaolinite in the upper 3 m of the summit weathering profile, which are weathering products of primary plagioclase, muscovite, and chlorite. The currently available clay mineralogy results are consistent with the decrease in total SSA from up to 20 m2g-1 at the surface to <5 m2g-1 below 3 m depth. Within the first 3 m from the surface, citrate-dithionate extractable iron contributed 30-60% of the total surface area. Therefore transformation of primary minerals to secondary phyllosilicate minerals, involving leaching loss of cations, was partly responsible for SSA production, but iron oxides play a significant role in production of SSA above the weathering front. This observation did not differ between

  16. Ground-based Observations of the Solar Sources of Space Weather

    NASA Astrophysics Data System (ADS)

    Veronig, A. M.; Pötzi, W.

    2016-04-01

    Monitoring of the Sun and its activity is a task of growing importance in the frame of space weather research and awareness. Major space weather disturbances at Earth have their origin in energetic outbursts from the Sun: solar flares, coronal mass ejections and associated solar energetic particles. In this review we discuss the importance and complementarity of ground-based and space-based observations for space weather studies. The main focus is drawn on ground-based observations in the visible range of the spectrum, in particular in the diagnostically manifold Hα spectral line, which enables us to detect and study solar flares, filaments (prominences), filament (prominence) eruptions, and Moreton waves. Existing Hα networks such as the GONG and the Global High-Resolution Hα Network are discussed. As an example of solar observations from space weather research to operations, we present the system of real-time detection of Hα flares and filaments established at Kanzelhöhe Observatory (KSO; Austria) in the frame of the space weather segment of the ESA Space Situational Awareness programme (swe.ssa.esa.int). An evaluation of the system, which is continuously running since July 2013 is provided, covering an evaluation period of almost 2.5 years. During this period, KSO provided 3020 hours of real-time Hα observations at the ESA SWE portal. In total, 824 Hα flares were detected and classified by the real-time detection system, including 174 events of Hα importance class 1 and larger. For the total sample of events, 95 % of the automatically determined flare peak times lie within ±5 min of the values given in the official optical flares reports (by NOAA and KSO), and 76 % of the start times. The heliographic positions determined are better than ±5°. The probability of detection of flares of importance 1 or larger is 95 %, with a false alarm rate of 16 %. These numbers confirm the high potential of automatic flare detection and alerting from ground

  17. Landscape Dissection in the Alakai Swamp on Kauai by Groundwater Enhanced Weathering and and Surface Water

    NASA Astrophysics Data System (ADS)

    Pederson, D. T.; Knapp, E.; Blay, C.; Gates, J. B.

    2011-12-01

    The Alakai Swamp lies on the high western-side of the shield volcano that created Kauai some 5 million years ago. The swamp itself rests on younger lower-gradient lava flows. The basalts are of mantle origin and usually weather rapidly and directly to clays on the island. The remnants of the high points of the shield volcano form a natural "rain making" geometry (with the trade winds) such that the highest points of the Alakai Swamp near the summit experience rainfalls around 1500 mm/yr tapering off to approximately 250 mm/yr in the lower northwestern part of the swamp. Frequent dense fogs also represent a source of moisture for plant growth. The surface of the swamp approximates a sloping plane surface dissected by headward advancing tributaries of the deeply incised Waimea Canyon. Areas of bog/swamps and dense taller vegetation are located in the headwaters and divide areas of tributaries. The bog/swamp areas have a pronounced dip parallel to the general paths of the incising tributaries and represent the local surface of saturation of a zone of chemical and organic reactions weathering (etching) the underlying basalts. Away from the bogs/swamps vegetation height is greater reflecting opportunities for greater root development. Headwaters areas of the tributaries are small with tributary discharge curves during rainfall events suggesting significant groundwater contributions. The tributary canyons are very steep-sided and wide in the lower reaches resulting in very narrow drainage divides. The steep canyon walls are a result of high weathering rates associated with vegetation growth enhanced by groundwater discharge. The rapid growth of roots is also very effective in breaking up rock creating additional surface areas for weathering which increases the rate of conversion of basalts to clay. There is a rapid narrowing of tributary canyons upstream, in places to notch canyons, which further supports the contention that groundwater supported weathering processes are

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

    NASA Technical Reports Server (NTRS)

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

    1992-01-01

    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

  19. A High-Resolution 3D Weather Radar, MSG, and Lightning Sensor Observation Composite

    NASA Astrophysics Data System (ADS)

    Diederich, Malte; Senf, Fabian; Wapler, Kathrin; Simmer, Clemens

    2013-04-01

    Within the research group 'Object-based Analysis and SEamless prediction' (OASE) of the Hans Ertel Centre for Weather Research programme (HerZ), a data composite containing weather radar, lightning sensor, and Meteosat Second Generation observations is being developed for the use in object-based weather analysis and nowcasting. At present, a 3D merging scheme combines measurements of the Bonn and Jülich dual polarimetric weather radar systems (data provided by the TR32 and TERENO projects) into a 3-dimensional polar-stereographic volume grid, with 500 meters horizontal, and 250 meters vertical resolution. The merging takes into account and compensates for various observational error sources, such as attenuation through hydrometeors, beam blockage through topography and buildings, minimum detectable signal as a function of noise threshold, non-hydrometeor echos like insects, and interference from other radar systems. In addition to this, the effect of convection during the radar 5-minute volume scan pattern is mitigated through calculation of advection vectors from subsequent scans and their use for advection correction when projecting the measurements into space for any desired timestamp. The Meteosat Second Generation rapid scan service provides a scan in 12 spectral visual and infrared wavelengths every 5 minutes over Germany and Europe. These scans, together with the derived microphysical cloud parameters, are projected into the same polar stereographic grid used for the radar data. Lightning counts from the LINET lightning sensor network are also provided for every 2D grid pixel. The combined 3D radar and 2D MSG/LINET data is stored in a fully documented netCDF file for every 5 minute interval, and is made ready for tracking and object based weather analysis. At the moment, the 3D data only covers the Bonn and Jülich area, but the algorithms are planed to be adapted to the newly conceived DWD polarimetric C-Band 5 minute interval volume scan strategy. An

  20. Interactive Computing and Processing of NASA Land Surface Observations Using Google Earth Engine

    NASA Technical Reports Server (NTRS)

    Molthan, Andrew; Burks, Jason; Bell, Jordan

    2016-01-01

    Google's Earth Engine offers a "big data" approach to processing large volumes of NASA and other remote sensing products. h\\ps://earthengine.google.com/ Interfaces include a Javascript or Python-based API, useful for accessing and processing over large periods of record for Landsat and MODIS observations. Other data sets are frequently added, including weather and climate model data sets, etc. Demonstrations here focus on exploratory efforts to perform land surface change detection related to severe weather, and other disaster events.

  1. Effects of UV weathering on surface properties of polypropylene composites reinforced with wood flour, lignin, and cellulose

    NASA Astrophysics Data System (ADS)

    Peng, Yao; Liu, Ru; Cao, Jinzhen; Chen, Yu

    2014-10-01

    In this study, the influence of accelerated weathering on polypropylene composites reinforced with wood flour (WF), lignin, and cellulose at different loading levels were evaluated. Six groups of samples were exposed in a QUV accelerated weathering tester for a total of 960 h. The surface color, surface gloss, contact angle and flexural properties of the samples were tested. Besides, the weathered surface was characterized by SEM and ATR-FTIR. The results revealed that (1) the discoloration of composites was accelerated by the presence of lignin, especially at high content; (2) composites containing lignin showed less loss of flexural strength and modulus, less cracks, and better hydrophobicity on weathered surface than other groups, confirming its functions of stabilization and antioxidation; (3) cellulose-based composites exhibited better color stability but more significant deterioration in flexural properties after weathering compared to other composites, suggesting that such kind of composites could not be used as load-bearing structure in outdoor applications.

  2. Cockpit weather information needs

    NASA Technical Reports Server (NTRS)

    Scanlon, Charles H.

    1992-01-01

    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 weather displays for the dispatcher, air traffic control (ATC), and pilot crew should also enhance the dialogue capabilities for reroute decisions. By utilizing a broadcast data link for surface observations, forecasts, radar summaries, lightning strikes, and weather alerts, onboard weather computing facilities construct graphical displays, historical weather displays, color textual displays, and other tools to assist the pilot crew. Since the weather data is continually being received and stored by the airborne system, the pilot crew has instantaneous access to the latest information. This information is color coded to distinguish degrees of category for surface observations, ceiling and visibilities, and ground radar summaries. Automatic weather monitoring and pilot crew alerting is accomplished by the airborne computing facilities. When a new weather information is received, the displays are instantaneously changed to reflect the new information. Also, when a new surface or special observation for the intended destination is received, the pilot crew is informed so that information can be studied at the pilot's discretion. The pilot crew is also immediately alerted when a severe weather notice, AIRMET or SIGMET, is received. The cockpit weather display shares a multicolor eight inch cathode ray tube and overlaid touch panel with a pilot crew data link interface. Touch sensitive buttons and areas are used for pilot selection of graphical and data link displays. Time critical ATC messages are presented in a small window that overlays other displays so that immediate pilot alerting and action can be taken. Predeparture and reroute clearances are displayed on the graphical weather system so pilot review of weather along

  3. State of Art in space weather observational activities and data management in Europe

    NASA Astrophysics Data System (ADS)

    Stanislawska, Iwona

    One of the primary scientific and technical goals of space weather is to produce data in order to investigate the Sun impact on the Earth and its environment. Studies based on data mining philosophy yield increase the knowledge of space weather physical properties, modelling capabilities and gain applications of various procedures in space weather monitoring and forecasting. Exchanging tailored individually and/or jointly data between different entities, storing of the databases and making data accessible for the users is the most important task undertaken by investigators. National activities spread over Europe is currently consolidated pursuant to the terms of effectiveness and individual contributions embedded in joint integrated efforts. The role of COST 724 Action in animation of such a movement is essential. The paper focuses on the analysis of the European availability in the Internet near-real time and historical collections of the European ground based and satellite observations, operational indices and parameters. A detailed description of data delivered is included. The structure of the content is supplied according to the following selection: (1) observations, raw and/or corrected, updated data, (2) resolution, availability of real-time and historical data, (3) products, as the results of models and theory including (a) maps, forecasts and alerts, (b) resolution, availability of real-time and historical data, (4) platforms to deliver data. Characterization of the networking of stations, observatories and space related monitoring systems of data collections is integrated part of the paper. According to these provisions operational systems developed for these purposes is presented and analysed. It concerns measurements, observations and parameters from the theory and models referred to local, regional collections, European and worldwide networks. Techniques used by these organizations to generate the digital content are identified. As the reference pan

  4. Data Assimilation of SMAP Observations and the Impact on Weather Forecasts and Heat Stress

    NASA Technical Reports Server (NTRS)

    Zavodsky, Bradley; Case, Jonathan; Blankenship, Clay; Crosson, William; White, Khristopher

    2014-01-01

    SPoRT produces real-time LIS soil moisture products for situational awareness and local numerical weather prediction over CONUS, Mesoamerica, and East Africa ?Currently interact/collaborate with operational partners on evaluation of soil moisture products ?Drought/fire ?Extreme heat ?Convective initiation ?Flood and water borne diseases ?Initial efforts to assimilate L2 soil moisture observations from SMOS (as a precursor for SMAP) have been successful ?Active/passive blended product from SMAP will be assimilated similarly and higher spatial resolution should improve on local-scale processes

  5. On the dynamic estimation of relative weights for observation and forecast in numerical weather prediction

    NASA Technical Reports Server (NTRS)

    Wahba, Grace; Deepak, A. (Editor)

    1988-01-01

    The problem of merging direct and remotely sensed (indirect) data with forecast data to get an estimate of the present state of the atmosphere for the purpose of numerical weather prediction is examined. To carry out this merging optimally, it is necessary to provide an estimate of the relative weights to be given to the observations and forecast. It is possible to do this dynamically from the information to be merged, if the correlation structure of the errors from the various sources is sufficiently different. Some new statistical approaches to doing this are described, and conditions quantified in which such estimates are likely to be good.

  6. Space Weather Observations by GNSS Radio Occultation: From FORMOSAT-3/COSMIC to FORMOSAT-7/COSMIC-2

    PubMed Central

    Yue, Xinan; Schreiner, William S; Pedatella, Nicholas; Anthes, Richard A; Mannucci, Anthony J; Straus, Paul R; Liu, Jann-Yenq

    2014-01-01

    The joint Taiwan-United States FORMOSAT-3/COSMIC (Constellation Observing System for Meteorology, Ionosphere, and Climate) mission, hereafter called COSMIC, is the first satellite constellation dedicated to remotely sense Earth's atmosphere and ionosphere using a technique called Global Positioning System (GPS) radio occultation (RO). The occultations yield abundant information about neutral atmospheric temperature and moisture as well as space weather estimates of slant total electron content, electron density profiles, and an amplitude scintillation index, S4. With the success of COSMIC, the United States and Taiwan are moving forward with a follow-on RO mission named FORMOSAT-7/COSMIC-2 (COSMIC-2), which will ultimately place 12 satellites in orbit with two launches in 2016 and 2019. COSMIC-2 satellites will carry an advanced Global Navigation Satellite System (GNSS) RO receiver that will track both GPS and Russian Global Navigation Satellite System signals, with capability for eventually tracking other GNSS signals from the Chinese BeiDou and European Galileo system, as well as secondary space weather payloads to measure low-latitude plasma drifts and scintillation at multiple frequencies. COSMIC-2 will provide 4–6 times (10–15X in the low latitudes) the number of atmospheric and ionospheric observations that were tracked with COSMIC and will also improve the quality of the observations. In this article we focus on COSMIC/COSMIC-2 measurements of key ionospheric parameters. PMID:26213514

  7. Optimal Sites for Supplementary Weather Observations: Simulation with a Small Model.

    NASA Astrophysics Data System (ADS)

    Lorenz, Edward N.; Emanuel, Kerry A.

    1998-02-01

    Anticipating the opportunity to make supplementary observations at locations that can depend upon the current weather situation, the question is posed as to what strategy should be adopted to select the locations, if the greatest improvement in analyses and forecasts is to be realized. To seek a preliminary answer, the authors introduce a model consisting of 40 ordinary differential equations, with the dependent variables representing values of some atmospheric quantity at 40 sites spaced equally about a latitude circle. The equations contain quadratic, linear, and constant terms representing advection, dissipation, and external forcing. Numerical integration indicates that small errors (differences between solutions) tend to double in about 2 days. Localized errors tend to spread eastward as they grow, encircling the globe after about 14 days.In the experiments presented, 20 consecutive sites lie over the ocean and 20 over land. A particular solution is chosen as the true weather. Every 6 h observations are made, consisting of the true weather plus small random errors, at every land site, and at one ocean site to be selected by the strategy being considered. An analysis is then made, consisting of observations where observations are made and previously made 6-h forecasts elsewhere. Forecasts are made for each site at ranges from 6 h to 10 days. In all forecasts, a slightly weakened external forcing is used to simulate the model error. This process continues for 5 years, and mean-square forecast errors at each site at each range are accumulated.Strategies that attempt to locate the site where the current analysis, as made without a supplementary observation, is most greatly in error are found to perform better than those that seek the oceanic site to which a chosen land site is most sensitive at a chosen range. Among the former are strategies based on the `breeding' method, a variant of singular vectors, and ensembles of `replicated' observations; the last of these

  8. An observed database to characterize the weather conditions associated with subtropical cyclogenesis over southern-southeastern Brazil

    NASA Astrophysics Data System (ADS)

    Yamamoto, R.; Porfirio da Rocha, R.

    2012-04-01

    A project to study the climatic, dynamic and synoptic aspects of subtropical cyclones that develop in southern-southeastern coast of Brazil is in development. The weather conditions associated with such cyclones is an important question that must be answered in this project. However, for such characterization it is necessary to use the local meteorological observations of wind, wind gust, rainfall, air temperature, etc. The NCEP (National Center for Environmental Prediction) reanalysis have spatial and time resolutions that provide elements to study the synoptic and dynamics of meteorological events (cyclone, anticyclones, troughs, ridges, monsoons circulations, etc) until the production of complex climatology. However, this analysis has coarse horizontal resolution (~250 Km) that often does not allow the identification of intense meteorological phenomena. A more precise characterization of location and intensity of weather conditions associated with subtropical cyclones would be performed using local observations. Therefore, this work describes the methodology to construct a database of surface weather observations using a relational database management system (RDBMS) MySQL. The data source are SYNOP (Surface Synoptic Observations), METAR (Meteorological Aerodrome Report), NCDC (National Climatic Data Center) and CETESB (Environmental Agency of Sao Paulo State) that are available online through dynamic web page. An iterative algorithm robot was developed to automate the data extraction. Most of the data source are encoded or at non-standard format, hence was developed an algorithm in C++, using the REGEX library, an engine of text pattern search, for decode and handle the exception (erroneous and corrupted data). After the data decoding and formatting it is stored into the MySQL database. The structure of database was divided into categories of tables: a table with the source of data definition, a table with stations information and two sets of tables (for hourly

  9. Implications of Non-Systematic Observations for Verification of Forecasts of Aviation Weather Variables

    NASA Astrophysics Data System (ADS)

    Brown, B. G.; Young, G. S.; Fowler, T. L.

    2001-12-01

    Over the last several years, efforts have been undertaken to develop improved automated forecasts of weather phenomena that have large impacts on aviation, including turbulence and in-flight icing conditions. Verification of these forecasts - which has played a major role in their development - is difficult due to the nature of the limited observations available for these evaluations; in particular, voice reports by pilots (PIREPs). These reports, which are provided inconsistently by pilots, currently are the best observations of turbulence and in-flight icing conditions available. However, their sampling characteristics make PIREPs a difficult dataset to use for these evaluations. In particular, PIREPs have temporal and spatial biases (e.g., they are more frequent during daylight hours, and they occur most frequently along flight routes and in the vicinity of major airports, where aircraft are concentrated), and they are subjective. Most importantly, the observations are non-systematic. That is, observations are not consistently reported at the same location and time. This characteristic of the reports has numerous implications for the verification of forecasts of these phenomena. In particular, it is inappropriate to estimate certain common verification statistics that normally are of interest in forecast evaluations. For example, estimates of the false alarm ratio and critical success index are incorrect, due to the unrepresentativeness of the observations. Analytical explanations for this result have been developed, and the magnitudes of the errors associated with estimating these statistics have been estimated through Monte Carlo simulations. In addition, several approaches have been developed to compensate for these characteristics of PIREPs in verification studies, including methods for estimating confidence intervals for the verification statistics, which take into account their sampling variability. These approaches also have implications for verification

  10. Assessing the Impact of Observations on Numerical Weather Forecasts Using the Adjoint Method

    NASA Technical Reports Server (NTRS)

    Gelaro, Ronald

    2012-01-01

    The adjoint of a data assimilation system provides a flexible and efficient tool for estimating observation impacts on short-range weather forecasts. The impacts of any or all observations can be estimated simultaneously based on a single execution of the adjoint system. The results can be easily aggregated according to data type, location, channel, etc., making this technique especially attractive for examining the impacts of new hyper-spectral satellite instruments and for conducting regular, even near-real time, monitoring of the entire observing system. This talk provides a general overview of the adjoint method, including the theoretical basis and practical implementation of the technique. Results are presented from the adjoint-based observation impact monitoring tool in NASA's GEOS-5 global atmospheric data assimilation and forecast system. When performed in conjunction with standard observing system experiments (OSEs), the adjoint results reveal both redundancies and dependencies between observing system impacts as observations are added or removed from the assimilation system. Understanding these dependencies may be important for optimizing the use of the current observational network and defining requirements for future observing systems

  11. An assessment of numerical weather prediction (NWP) models surface soil temperature products using ground-based measurements

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Numerical weather prediction (NWP) models developed by various weather centers produce estimates of the soil temperature state. In this study in situ data collected over the state of Oklahoma is used to assess and compare three NWP surface (soil) temperature products. These are 1) the integrated for...

  12. Surface anisotropy characterisation with meteosat observations

    NASA Astrophysics Data System (ADS)

    Lattanzio, A.; Govaerts, Y. M.; Pinty, B.

    Surface albedo, or more precisely Directional Hemispherical Reflectance (DHR), is the integral the Bi-directional Reflectance Factor (BRF) of the surface over all angles of the upward hemisphere. The retrieval of the DHR trough space observations requires accounting for the scattering and absorption processes in the atmosphere as well as for the angular anisotropy of the surface, the two systems being radiatively coupled. The accuracy achieved in the albedo estimation depends thus on the density of the angular sampling and the reliability of the atmospheric correction. Pinty et al. demonstrated the possibility to derive reliable surface albedo from observations acquired by Meteosat, the European meteorological geostationary satellite. The purpose of this presentation is to analyse the accuracy of this new Meteosat Surface Albedo (MSA) product, including the effects due to instrument changes and associated calibration uncertainties. In particular, the consistency of the surface anisotropy characterisation is examined in detail. To this end, observations acquired by two adjacent geostationary spacecrafts, i.e., Meteosat-7 and Meteosat-5 have been processed with the MSA algorithm. These satellites are located respectively at 0 and 63 degrees East. Data acquired by these two instruments overlap over a large area encompassing most of Africa and the Arabian Peninsula. The consistency of the surface anisotropy retrieval is evaluated through a reconstruction of the Meteosat-5 (-7) observations with the Meteosat-7 (-5) surface anisotropy characterisation. No differences larger than the calibration uncertainties have been found, which indicates that the MSA algorithm accounts correctly for the surface anisotropy and instrument differences.

  13. Real-time Observations of Rock Cracking and Weather Provide Insights into Thermal Stress-Related Processes of Mechanical Weathering.

    NASA Astrophysics Data System (ADS)

    Eppes, M. C.; Magi, B. I.; Keanini, R.

    2015-12-01

    The environmental conditions (weather and/or climate) that limit or drive mechanical weathering via thermal stress are poorly understood. Here we examine acoustic emission (AE) records of rock cracking in boulders sitting on the ground in humid-temperate (~1 year of data) and semi-arid (~3 years) locations. We compare on-site average ambient daily temperature for days in which cracking occurs to the average temperatures for those dates derived from local climate records. The temperatures characterizing days on which cracking occurs is similar for both stations (range = -10 C to +30 C); where 21% and 73% of cracking occurs on hot days (> 20C) in the humid and semi-arid climates respectively while 17% and 0.1% occurs on very cold days (-8C to -3C). When days during which cracking occurs are compared to climate averages, 81% (NC) and 51% (NM) of all cracking occurs on days with absolute temperature anomalies >1, regardless of the temperature. The proportion of cracking that occurs on anomalously hot or cold days rises to 92% and 77% when the data is normalized to account for uneven sampling of the days with extreme temperatures. In order to determine to what extent this trend holds true in a more complex setting, we examined an existing 100+ year record of rock falls from Yosemite Valley. Preliminary results, although more equivocal, are consistent with the boulder cracking AE data. We examine the AE datasets in the context of our previous numerical modeling of insolation-driven thermal stress in rock and hypothesize that there is an increased potential for fracture on days with extreme temperatures because 1) thermal-stress is dependent on temperature variance from far-field and/or average rock temperatures and 2) that days with climatologically extreme air temperatures result in maximums in such variance. An implication of our results is that environments with extreme weather variability may have higher thermal breakdown rates, including certain locations today and

  14. Evaluating the Impacts of NASA/SPoRT Daily Greenness Vegetation Fraction on Land Surface Model and Numerical Weather Forecasts

    NASA Technical Reports Server (NTRS)

    Bell, Jordan R.; Case, Jonathan L.; Molthan, Andrew L.

    2011-01-01

    The NASA Short-term Prediction Research and Transition (SPoRT) Center develops new products and techniques that can be used in operational meteorology. The majority of these products are derived from NASA polar-orbiting satellite imagery from the Earth Observing System (EOS) platforms. One such product is a Greenness Vegetation Fraction (GVF) dataset, which is produced from Moderate Resolution Imaging Spectroradiometer (MODIS) data aboard the NASA EOS Aqua and Terra satellites. NASA SPoRT began generating daily real-time GVF composites at 1-km resolution over the Continental United States (CONUS) on 1 June 2010. The purpose of this study is to compare the National Centers for Environmental Prediction (NCEP) climatology GVF product (currently used in operational weather models) to the SPoRT-MODIS GVF during June to October 2010. The NASA Land Information System (LIS) was employed to study the impacts of the new SPoRT-MODIS GVF dataset on land surface models apart from a full numerical weather prediction (NWP) model. For the 2010 warm season, the SPoRT GVF in the western portion of the CONUS was generally higher than the NCEP climatology. The eastern CONUS GVF had variations both above and below the climatology during the period of study. These variations in GVF led to direct impacts on the rates of heating and evaporation from the land surface. The second phase of the project is to examine the impacts of the SPoRT GVF dataset on NWP using the Weather Research and Forecasting (WRF) model. Two separate WRF model simulations were made for individual severe weather case days using the NCEP GVF (control) and SPoRT GVF (experimental), with all other model parameters remaining the same. Based on the sensitivity results in these case studies, regions with higher GVF in the SPoRT model runs had higher evapotranspiration and lower direct surface heating, which typically resulted in lower (higher) predicted 2-m temperatures (2-m dewpoint temperatures). The opposite was true

  15. Widespread surface weathering on early Mars: A case for a warmer and wetter climate

    NASA Astrophysics Data System (ADS)

    Carter, John; Loizeau, Damien; Mangold, Nicolas; Poulet, François; Bibring, Jean-Pierre

    2015-03-01

    Early Mars (>3 Ga) underwent aqueous alteration as evidenced by fluvial/lacustrine morphologies and the recent discovery of widespread hydrous clays. Despite compelling evidence for diverse and localized aqueous environments, the possibility for sustained liquid water globally on the martian surface and over geological timescales is still highly debated. Instead, a durably cold and dry Mars scenario is often proposed. By studying specific Fe/Mg and Al-rich clay stratigraphies on Mars by means of a planetary scale orbital investigation, we present new evidence that Mars experienced an early era (>3.7 Ga) of widespread aqueous alteration consistent with surface weathering.

  16. A much warmer Earth surface for most of geologic time: implications to biotic weathering

    NASA Technical Reports Server (NTRS)

    Schwartzman, D. W.; McMenamin, M.

    1993-01-01

    The authors present two scenarios for the temperature history of Earth. One scenario is conventional, the other relies on a warmer history. Both scenarios include surface cooling determined by the evolution of the biosphere and are similar until the Proterozoic period. The warmer scenario requires a higher plant/lichen terrestrial biota to increase weathering intensity. Justification for a warmer surface includes period temperatures from the oxygen isotope record of coexisting phosphates and cherts, an upper limit of 58 degrees C from primary gypsum precipitation, and the lack of fractionation of sulfur isotopes between sulfide and sulfates in Archean sediments.

  17. Surface-Correlated Nanophase Iron Metal in Lunar Soils: Petrography and Space Weathering Effects

    NASA Technical Reports Server (NTRS)

    Keller, Lindsay P.; Wentworth, Susan J.; McKay, David S.

    1998-01-01

    Space weathering is a term used to include all of the processes that act on material exposed at the surface of a planetary or small body. In the case of the Moon, it includes a variety of processes that formed the lunar regolith, caused the maturation of lunar soils, and formed patina on rock surfaces. The processes include micrometeorite impact and reworking, implantation of solar wind and flare particles, radiation damage and chemical effects from solar particles and cosmic rays, interactions with the lunar atmosphere, and sputtering erosion and deposition. Space weathering effects collectively result in a reddened continuum slope, lowered albedo, and attenuated absorption features in reflectance spectra of lunar soils as compared to finely comminuted rocks from the same Apollo sites. Understanding these effects is critical in order to fully integrate the lunar sample collection with remotely sensed data from recent robotic missions (e.g., Lunar Prospector, Clementine, Galileo). Our objective is to determine the origin of space weathering effects in lunar soils through combined electron microscopy and microspectrophotometry techniques applied to individual soil particles from <20 pm size factions (dry-sieved) of mature lunar soils. It has been demonstrated that it is the finest size fraction (<25 pm) of lunar soils that dominates the optical properties of the bulk soils.

  18. An Assessment of Optimality of Observations in High-resolution Weather Forecasting

    NASA Astrophysics Data System (ADS)

    Goswami, Prashant; Rakesh, V.

    2016-04-01

    Data assimilation is a critical component for short-range weather forecasting; a number of algorithms have been developed and applied for assimilation of different kind of observations. However, an important but less explored question is the (optimal) amount of observation for maximum improvement in forecasts through data assimilation. Because the meteorological fields at different spatial and temporal resolutions are not necessarily mutually independent, indefinite increase in resolution of observations may be ineffective; thus data optimality in this sense can be defined as the maximum resolution of observation beyond which no appreciable improvement occurs due to assimilation of data. Based on forecasts of seven events over a complex terrain (urban location, Delhi) with different combinations of observations, we show that improvement in forecast skill does not saturate even with assimilation of observations a few kilometers (<10 km) apart. The improvement due to assimilation of data from each of the profilers is appreciable; however, the impact was generally the highest for assimilation of data from all the four profilers. Applicable strategies for observation system design over high-impact areas are discussed.

  19. Effects of copper-plasma deposition on weathering properties of wood surfaces

    NASA Astrophysics Data System (ADS)

    Gascón-Garrido, P.; Mainusch, N.; Militz, H.; Viöl, W.; Mai, C.

    2016-03-01

    Thin layers of copper micro-particles were deposited on the surfaces of Scots pine (Pinus sylvestris L.) micro-veneers using atmospheric pressure plasma to improve the resistance of the surfaces to weathering. Three different loadings of copper were established. Micro-veneers were exposed to artificial weathering in a QUV weathering tester for 0, 24, 48, 96 and 144 h following the standard EN 927-6 [1]. Mass losses after each exposure showed significant differences between copper coated and untreated micro-veneers. Tensile strength was assessed at zero span (z-strength) and finite span (f-strength) under dry conditions (20 °C, 65% RH). During 48 h, micro-veneers lost their z-strength progressively. In contrast, copper coating at highest loading imparts a photo-protective effect to wood micro-veneers during 144 h exhibiting z-strength retention of 95%. F-strength losses were similar in all copper treated and untreated micro-veneers up to 96 h. However, after 144 h, copper coated micro-veneers at highest loading showed significantly greater strength retention of 56%, while untreated micro-veneers exhibited only 38%. Infrared spectroscopy suggested that copper coating does not stabilize lignin. Inductively Coupled Plasma revealed that micro-veneers coated with the highest loading exhibited the lowest percentage of copper loss. Blue stain resistance of copper coated Scots pine following the guidelines of EN 152 [2] was performed. Additional test with different position of the coated surface was also assessed. Copper coating reduced fungal growth when coated surface is exposed in contact with vermiculite. Spores of Aureobasidium pullulans were not able to germinate on the copper coated surface positioned uppermost.

  20. Surface Exposure Ages of Space-Weathered Grains from Asteroid 25143 Itokawa

    NASA Technical Reports Server (NTRS)

    Keller, L. P.; Berger, E. L.; Christoffersen, R.

    2015-01-01

    We use the observed effects of solar wind ion irradiation and the accumulation of solar flare particle tracks recorded in Itokawa grains to constrain the rates of space weathering and yield information about regolith dynamics. The track densities are consistent with exposure at mm depths for 104-105 years. The solar wind damaged rims form on a much faster timescale, <10(exp 3) years.

  1. Increased Surface Albedo in the Northern Hemisphere: Did satellites warn of the weather troubles of 1972 and 1973?

    PubMed

    Kukla, G J; Kukla, H J

    1974-02-22

    Routine mapping of snow and ice fields in the northern hemisphere was started by NOAA in 1967. Large year-to-year variations of the snow and pack-ice covers were observed. The annual mean coverage increased by 12 percent during 1971 and has remained high. The index R, which shows the approximate amount of energy reflected from the surface by snow and ice under the mean cloudiness, increased correspondingly. Thus, if the cloud cover over the snow fields did not increase substantially, the anomalous weather patterns of 1972 and 1973 could have been connected with the deficit in surface heat exchange which originated in the northern hemisphere the year before. During the past 7 years the largest changes occurred in the fall and in the continental interiors of Asia and America (8). Two synoptic parameters which could readily provide information on the development of snow and ice cover in the northern hemisphere are (i) the total area momentarily covered and (ii) the running annual mean of snow and ice coverage for the preceding 1-year period. By 20 September 1973 the annual mean coverage was 37.3 x 10(6) km(2), 11 to 12 percent higher than at the same time during 1968 through 1970. Snow cover-fall, the season when 15 x 10(6) to 55 x 10(6) km(2) of the northern hemisphere is covered with snow and ice, started on 20 September 1973, compared to 17 September 1972 and 5 or 10 October during 1967 through 1970. The links between the atmosphere, the oceans, and the land surfaces must be better understood before the role of snow and ice can be thoroughly explained and exploited for long-range weather forecasting. But it is clear that snow, hitherto almost overlooked in synoptic meteorological reports, must be important in the mechanism of weather changes. PMID:17790616

  2. Frost weathering and rockwall erosion in the southeastern Swiss Alps: Long-term (1994 2006) observations

    NASA Astrophysics Data System (ADS)

    Matsuoka, Norikazu

    2008-07-01

    Rates and processes of frost weathering in the Alps were investigated by visual observations of intensively shattered rocks, continuous monitoring of frost wedging and rock temperatures in bedrock and measurements of rockfall activity. Rapid frost weathering of hard-intact rocks occurs along lakes and streams where seasonal freezing promotes ice segregation in the rock. Otherwise, rocks require pre-existing weakness or a long exposure period for intensively shattered. Automated monitoring shows that crack opening occurs at three scales, including small opening accompanying short-term frost cycles, slightly larger movements during seasonal freezing and occasional large opening originating from refreezing of snow-melt water during seasonal thawing. The opening events require at least partial water saturation in the crack. The repetition of crack opening (frost wedging) results in permanent opening and finally debris dislocation. Debris collections below fractured rockwalls show that pebble falls occur at an average rate of about 0.1 mm a - 1 with significant spatial and inter-annual variations. Occasional large boulder falls significantly raise the rockwall erosion rates, controlled by such factors as the joint distribution in the bedrock, repetition of annual freeze-thaw cycles and extraordinary summer thaw.

  3. A Ground-Based Array to Observe Geospace Electrodynamics During Adverse Space Weather Conditions

    NASA Astrophysics Data System (ADS)

    Sojka, J. J.; Eccles, J. V.; Rice, D.

    2004-05-01

    Geomagnetic Storms occur with surprising frequency and create adverse space weather conditions. During these periods, our knowledge and ability to specify or forecast in adequate detail for user needs is negligible. Neither experimental observations nor theoretical developments have made a significant new impact on the problem for over two decades. Although we can now map Total Electron Content (TEC) in the ionosphere over a continent with sufficient resolution to see coherent long-lived structures, these do not provide constraints on the geospace electrodynamics that is at the heart of our lack of understanding. We present arguments for the need of a continental deployment of ground-based sensors to stepwise advance our understanding of the geospace electrodynamics when it is most adverse from a space weather perspective and also most frustrating from an understanding of Magnetosphere-Ionosphere coupling. That a continental-scale deployment is more productive at addressing the problem than a realizable global distribution is shown. Each measurement is discussed from the point-of-view of either providing new knowledge or becoming a key for future real-time specification and forecasting for user applications. An example of a storm database from one mid-latitude station for the 31 March 2002 is used as a conceptual point in a ground-based array. The presentation focuses on scientific questions that have eluded a quantitative solution for over three decades and view a ground-based array as an "IGY" type of catalyst for answering these questions.

  4. Surface rheological observations on human plasma.

    PubMed

    Matrai, A; Warburton, B; Dormandy, J A

    1984-01-01

    The weak interactions between plasma proteins are of possible importance both in haemorheology and in the pathology of several diseases. The use of surface rheology is a convenient way to study the forces arising between surface adsorbed protein molecules. A surface rheological measuring head has been designed for the Contraves LS-30 viscometer. Plasma samples of healthy human subjects showed a rapidly developing viscous surface layer with a mean peak value of 2.10(-3) Ns/m surface viscosity at 30- 60 seconds. After that the viscosity of the surface layer gradually decreased to zero between 8-20 minutes. The rate of the observed decrease was not related to shearing. There was no difference between samples anticoagulated with heparin or EDTA. The time course of the described phenomenon coincides with that of thrombocyte and white cell adherence to solid surfaces exposed to plasma. PMID:6591960

  5. AIRS Observations of DomeC in Antarctica and Comparison with Automated Weather Stations (AWS)

    NASA Technical Reports Server (NTRS)

    Aumann, Hartmut H.; Gregorich, Dave; Broberg, Steve

    2006-01-01

    We compare the surface temperatures at Dome Concordia (DomeC) deduced from AIRS data and two Automatic Weather Stations at Concordia Station: AWS8989 , which has been in operation since December 1996, and AWS.it, for which data are available between January and November 2005. The AWS8989 readings are on average 3 K warmer than the AWS.it readings, with a warmer bias in the Antarctic summer than in the winter season. Although AIRS measures the skin brightness temperature, while the AWS reports the temperature of the air at 3 meter above the surface, the AIRS measurements agree well with the AWS.it readings for all data and separately for the summer and winter seasons, if data taken in the presence of strong surface inversions are filtered out. This can be done by deducing the vertical temperature gradient above the surface directly from the AIRS temperature sounding channels or indirectly by noting that extreme vertical gradients near the surface are unlikely if the wind speed is more than a few meters per second. Since the AIRS measurements are very well calibrated, the agreement with AWS.it is very encouraging. The warmer readings of AWS8989 are likely due to thermal contamination of the AWS8989 site by the increasing activity at Concordia Station. Data from an AWS.it quality station could be used for the evaluation of radiometric accuracy and stability of polar orbiting sounders at low temperatures. Unfortunately, data from AWS.it was available only for a limited time. The thermal contamination of the AWS8989 data makes long-term trends deduced from AWS8989 and possibly results about the rapid Antarctic warming deduced from other research stations on Antarctica suspect. AIRS is the first hyperspectral infrared sounder designed in support of weather forecasting and climate research. It was launched in May 2002 on the EOS Aqua spacecraft into a 704 km altitude polar sun-synchronous orbit. The lifetime of AIRS, estimated before launch to be at least 5 years is

  6. Problems at the Leading Edge of Space Weathering as Revealed by TEM Combined with Surface Science Techniques

    NASA Astrophysics Data System (ADS)

    Christoffersen, R.; Dukes, C. A.; Keller, L. P.; Rahman, Z.; Baragiola, R. A.

    2015-11-01

    Analytical field-emission TEM techniques cross-correlated with surface analyses by X-ray photoelectron spectroscopy (XPS) provides a unique two-prong approach for characterizing how solar wind ion processing contributes to space weathering.

  7. Biochemical evolution II: origin of life in tubular microstructures on weathered feldspar surfaces.

    PubMed

    Parsons, I; Lee, M R; Smith, J V

    1998-12-22

    Mineral surfaces were important during the emergence of life on Earth because the assembly of the necessary complex biomolecules by random collisions in dilute aqueous solutions is implausible. Most silicate mineral surfaces are hydrophilic and organophobic and unsuitable for catalytic reactions, but some silica-rich surfaces of partly dealuminated feldspars and zeolites are organophilic and potentially catalytic. Weathered alkali feldspar crystals from granitic rocks at Shap, north west England, contain abundant tubular etch pits, typically 0.4-0.6 microm wide, forming an orthogonal honeycomb network in a surface zone 50 microm thick, with 2-3 x 10(6) intersections per mm2 of crystal surface. Surviving metamorphic rocks demonstrate that granites and acidic surface water were present on the Earth's surface by approximately 3.8 Ga. By analogy with Shap granite, honeycombed feldspar has considerable potential as a natural catalytic surface for the start of biochemical evolution. Biomolecules should have become available by catalysis of amino acids, etc. The honeycomb would have provided access to various mineral inclusions in the feldspar, particularly apatite and oxides, which contain phosphorus and transition metals necessary for energetic life. The organized environment would have protected complex molecules from dispersion into dilute solutions, from hydrolysis, and from UV radiation. Sub-micrometer tubes in the honeycomb might have acted as rudimentary cell walls for proto-organisms, which ultimately evolved a lipid lid giving further shelter from the hostile outside environment. A lid would finally have become a complete cell wall permitting detachment and flotation in primordial "soup." Etch features on weathered alkali feldspar from Shap match the shape of overlying soil bacteria. PMID:9860941

  8. The influence of variations of vegetation and soil moisture on surface weather and atmospheric circulation

    SciTech Connect

    Yang, R.

    1992-01-01

    The influence of variations of vegetation and soil moisture on surface weather and atmospheric circulation is studied through the use of the Simple Biosphere Model (SiB) and the Center for Ocean-Land-Atmosphere interactions (COLA) GCM. Tests for the SiB sensitivity to the conversion of the forest to other short vegetation or bare soil were performed at Amazonian and Great Plains sites, and a North Wales spruce forest site respectively. The results show that deforestation has a significant influence on the local surface energy budget and surface weather. The influence is especially prominent at the Amazon and Great Plains sites, and larger in summer than in other seasons. The influence on the partitioning of surface incoming radiative energy is generally constrained by the local atmospheric boundary condition. The sensitivity of the COLA GCM to changes in initial soil wetness (ISW) is determined by repeating three 10-day model integrations with the same initial and boundary conditions as the control runs except the values of ISW, which are revised at 69 model grid points covering much of the continental U.S. It is found that the relations between the changes in the 5-day mean forecast surface air temperature/surface specific humidity and the changes in ISW depend upon vegetation type and the values of ISW, and can be approximated by regression equations. These relations are also confirmed with independent data. With the ISW revised based on these regression equations the surface forecasts of the revised runs are consistently improved. The spatial scale of the ISW anomaly determines the degree and range of the influence. The influence of a small regional ISW change is mainly confined to the local region and to low atmospheric levels. The influence on surface fluxes is strong and persists for more than one month, but the effects on precipitation are relatively weak, changeable, and complex, particularly when an interactive cloud scheme is used.

  9. Characterization of surface chemistry and crystallization behavior of polypropylene composites reinforced with wood flour, cellulose, and lignin during accelerated weathering

    NASA Astrophysics Data System (ADS)

    Peng, Yao; Liu, Ru; Cao, Jinzhen

    2015-03-01

    In this study, six groups of polypropylene composites reinforced with wood flour (WF), cellulose, and lignin at different loading levels were exposed in a QUV accelerated weathering tester for a total duration of 960 h. The changes in surface morphology, chemistry, and thermal properties of weathered samples were characterized by atomic force microscope (AFM), attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), and differential scanning calorimetric (DSC), respectively. The flexural properties of all samples were tested after different durations of weathering. The results showed that: (1) the surface roughness of all samples increased after weathering; (2) composites containing lignin showed less loss of flexural strength and modulus and less roughness on weathered surface compared with lignin-free composites, indicating the functions of stabilization and antioxidation of lignin; (3) the crystallinity of PP increased in all weathered samples due to chain scissions and recrystallization; (4) ATR-FTIR and XPS analyses demonstrated in detail that significant changes occurred in surface chemistry, accompanied by the photodegradation and photo-oxidation of lignin and cellulose with prolonged weathering time.

  10. Plateau weather: A synoptic study of IAGO and ANARE observations in east Antarctica

    SciTech Connect

    Radok, U.; Wendler, G.

    1992-03-01

    Automatic weather stations (AWS) have been operated for a number of years by U.S. and French scientists cooperating in Project Interactions Atmosphere, Glace, Ocean (IAGO) and by the Australian National Antarctic Research Expeditions (ANARE). Six of these stations are sufficiently close to one another on the East Antarctic Plateau for a synoptic interpretation of their observations. The data for 1987 have been reduced to a common format in order to identify episodes of regionally coherent changes. One of these episodes is described and used to outline steps that will be needed for clarifying the relative importance of the local energy balance and the large-scale circulation for the onset, duration, and cessation of katabatic winds on the plateau.

  11. A twenty-first century California observing network for monitoring extreme weather events

    USGS Publications Warehouse

    White, A.B.; Anderson, M.L.; Dettinger, M.D.; Ralph, F.M.; Hinojosa, A.; Cayan, D.R.; Hartman, R.K.; Reynolds, D.W.; Johnson, L.E.; Schneider, T.L.; Cifelli, R.; Toth, Z.; Gutman, S.I.; King, C.W.; Gehrke, F.; Johnston, P.E.; Walls, C.; Mann, Dorte; Gottas, D.J.; Coleman, T.

    2013-01-01

    During Northern Hemisphere winters, the West Coast of North America is battered by extratropical storms. The impact of these storms is of paramount concern to California, where aging water supply and flood protection infrastructures are challenged by increased standards for urban flood protection, an unusually variable weather regime, and projections of climate change. Additionally, there are inherent conflicts between releasing water to provide flood protection and storing water to meet requirements for water supply, water quality, hydropower generation, water temperature and flow for at-risk species, and recreation. In order to improve reservoir management and meet the increasing demands on water, improved forecasts of precipitation, especially during extreme events, is required. Here we describe how California is addressing their most important and costliest environmental issue – water management – in part, by installing a state-of-the-art observing system to better track the area’s most severe wintertime storms.

  12. HF Radar Observations of Space Weather Effects in the Low and Mid-latitude Ionosphere

    NASA Astrophysics Data System (ADS)

    Menk, F. W.

    2015-12-01

    The ionosphere is dynamically coupled to the magnetosphere and hence diurnal and seasonal processes in the ionosphere are strongly influenced by space weather effects. These may vary the electron density distribution and cause changes in the reflection and absorption of HF radio signals. Other consequences include the formation of enhanced convective flows and irregularity features which may contribute to Doppler clutter. While there has been much discussion on the ionospheric signatures of magnetic storms at high latitudes, this presentation focuses on effects detected using mid- and low-latitude HF radars which examine field lines mapping to the vicinity of the ring current. Characteristic features include travelling ionospheric disturbances, high velocity flows and sustained irregular and quasi-sinusoidal 5 - 20 mHz waves recorded near the plasmapause. Such observations provide new insight on complex M-I coupling dynamics.

  13. Surface degradation of CeO2 stabilized acrylic polyurethane coated thermally treated jack pine during accelerated weathering

    NASA Astrophysics Data System (ADS)

    Saha, Sudeshna; Kocaefe, Duygu; Boluk, Yaman; Pichette, Andre

    2013-07-01

    The thermally treated wood is a new value-added product and is very important for the diversification of forestry products. It drew the attention of consumers due to its attractive dark brown color. However, it loses its color when exposed to outside environment. Therefore, development of a protective coating for this value added product is necessary. In the present study, the efficiency of CeO2 nano particles alone or in combination with lignin stabilizer and/or bark extracts in acrylic polyurethane polymer was investigated by performing an accelerated weathering test. The color measurement results after accelerated weathering demonstrated that the coating containing CeO2 nano particles was the most effective whereas visual assessment suggested the coating containing CeO2 nano particles and lignin stabilizer as the most effective coating. The surface polarity changed for all the coatings during weathering and increase in contact angle after weathering suggested cross linking and reorientation of the polymer chain during weathering. The surface chemistry altered during weathering was evaluated by ATR-FTIR analysis. It suggested formation of different carbonyl byproducts during weathering. The chain scission reactions of the urethane linkages were not found to be significant during weathering.

  14. Surface Material Analysis of the S-type Asteroids: Removing the Space Weathering Effect from Reflectance Spectrum

    NASA Technical Reports Server (NTRS)

    Ueda, Y.; Miyamoto, M.; Mikouchi, T.; Hiroi, T.

    2003-01-01

    Recent years, many researchers have been observing a lot of asteroid reflectance spectra in the UV, visible to NIR at wavelength region. Reflectance spectroscopy of asteroid at this range should bring us a lot of information about its surface materials. Pyroxene and olivine have characteristic absorption bands in this wavelength range. Low-Ca pyroxene has two absorption bands around 0.9 microns and 1.9 microns. The more Ca and Fe content, the longer both absorption band centers. On the other hand, reflectance spectrum of olivine has three complicated absorption bands around 1 m, and no absorption feature around 2 microns. In general, reflectance spectra of many asteroids that are considered to be silicate rich (i.e., S- and A type asteroids) show redder slope and more subdued absorption bands than those of terrestrial minerals and meteorites. These features are now believed to be caused by the space weathering effect, which is probably caused by micrometeorite bombardment and/or solar wind. This process causes nanophase reduced iron (npFe(sup 0)) particles near the surface of mineral grains, which leads the optical change. Therefore, the space weathering effect should be removed from asteroid reflectance spectra to compare with those of meteorite and terrestrial minerals. In this report, we will apply the expanded modified Gaussian model (MGM) to the reflectance spectra of S-type asteroids 7 Iris and 532 Herculina and compare them with those of meteorites.

  15. Venus surface mineralogy - Observational and theoretical constraints

    NASA Technical Reports Server (NTRS)

    Fegley, Bruce, Jr.; Treiman, Allan H.; Sharpton, Virgil L.

    1992-01-01

    Earth-based, earth-orbital, and spacecraft observations of the atmosphere and surface of Venus, thermodynamic models of atmosphere-lithosphere interactions, and where available kinetic data on relevant gas-solid reactions to place constraints on the mineralogy of the surface of Venus are used. Which minerals and mineral assemblages are stable on the surface of Venus and which, if any, of these minerals are involved in controlling the abundances of reactive gases in the atmosphere of Venus. It is concluded by identifying key issues facing us today about the mineralogy and geochemistry of the surface of Venus and suggest experimental, observational, and theoretical studies that can improve knowledge of these important questions are discussed.

  16. Wilson surface observables from equivariant cohomology

    NASA Astrophysics Data System (ADS)

    Alekseev, Anton; Chekeres, Olga; Mnev, Pavel

    2015-11-01

    Wilson lines in gauge theories admit several path integral descriptions. The first one (due to Alekseev-Faddeev-Shatashvili) uses path integrals over coadjoint orbits. The second one (due to Diakonov-Petrov) replaces a 1-dimensional path integral with a 2-dimensional topological σ-model. We show that this σ-model is defined by the equivariant extension of the Kirillov symplectic form on the coadjoint orbit. This allows to define the corresponding observable on arbitrary 2-dimensional surfaces, including closed surfaces. We give a new path integral presentation of Wilson lines in terms of Poisson σ-models, and we test this presentation in the framework of the 2-dimensional Yang-Mills theory. On a closed surface, our Wilson surface observable turns out to be nontrivial for G non-simply connected (and trivial for G simply connected), in particular we study in detail the cases G=U(1) and G=SO(3).

  17. Daymet: Daily Surface Weather Data on a 1-km Grid for North America, Version 2.

    NASA Astrophysics Data System (ADS)

    Devarakonda, R.

    2014-12-01

    Daymet: Daily Surface Weather Data and Climatological Summaries provides gridded estimates of daily weather parameters for North America, including daily continuous surfaces of minimum and maximum temperature, precipitation occurrence and amount, humidity, shortwave radiation, snow water equivalent, and day length. The current data product (Version 2) covers the period January 1, 1980 to December 31, 2013 [1]. Data are available on a daily time step at a 1-km x 1-km spatial resolution in Lambert Conformal Conic projection with a spatial extent that covers the North America as meteorological station density allows. Daymet data can be downloaded from 1) the ORNL Distributed Active Archive Center (DAAC) search and order tools (http://daac.ornl.gov/cgi-bin/cart/add2cart.pl?add=1219) or directly from the DAAC FTP site (http://daac.ornl.gov/cgi-bin/dsviewer.pl?ds_id=1219) and 2) the Single Pixel Tool (http://daymet.ornl.gov/singlepixel.html) and THREDDS (Thematic Real-time Environmental Data Services) Data Server (TDS) (http://daymet.ornl.gov/thredds_mosaics.html). The Single Pixel Data Extraction Tool [2] allows users to enter a single geographic point by latitude and longitude in decimal degrees. A routine is executed that translates the (lon, lat) coordinates into projected Daymet (x,y) coordinates. These coordinates are used to access the Daymet database of daily-interpolated surface weather variables. The Single Pixel Data Extraction Tool also provides the option to download multiple coordinates programmatically. The ORNL DAAC's TDS provides customized visualization and access to Daymet time series of North American mosaics. Users can subset and download Daymet data via a variety of community standards, including OPeNDAP, NetCDF Subset service, and Open Geospatial Consortium (OGC) Web Map/Coverage Service. References: [1] Thornton, P. E., Thornton, M. M., Mayer, B. W., Wilhelmi, N., Wei, Y., Devarakonda, R., & Cook, R. (2012). "Daymet: Daily surface weather on a 1

  18. Weatherability Evaluation of Nanocomposite Polymeric Treatments for Surface Protection of Construction Materials

    SciTech Connect

    Scarfato, Paola; Letizia Fariello, Maria; Di Maio, Luciano; Incarnato, Loredana

    2010-06-02

    In this work the protective efficacy and stability against UV weathering of polymeric nanocomposites for concrete (CLS) surface protection have been evaluated. In particular, nanocomposite hybrids were prepared dispersing a commercial organomodified montmorillonite (Cloisite 30B) in two different polymeric matrices, one based on fluoroelastomers (Fluoline CP), the other on silane and siloxane (Antipluviol S). The obtained systems were characterized by several techniques (SAXD, DSC, TGA, FT-IR, contact angle measurements, colorimetry), before and after accelerated aging due to UV exposure, in order to evaluate the effect of the nanoscale dispersion of the organoclay on the properties and the UV stability of the treatments.

  19. Development of a surface-specific, anti-weathering stone preservative treatment

    SciTech Connect

    Rao, S.M.; Brinkar, C.J.; Rao, S.M.; Ross, T.J.

    1997-04-01

    We are testing an anti-weathering preservation strategy that is specific to limestone surfaces. The strategy involves the application of a mineral-specific, bifunctional, passivating/coupling agent that binds to both the limestone surface and to the consolidating inorganic polymer matrix. The sol-gel based reactions form composite materials with desirable conservation and anti-weathering properties. We present the results of our efforts, the highlights of which are: (1) scanning probe microscopy of moisture-free calcite crystals treated with the trisilanol form of silylalkylaminocarboxylate (SAAC), reveals porous agglomerates that offer no significant resistance to the mild leaching action of deionized water. When the crystals are further consolidated with a silica-based consolidant (A2**), no dissolution is seen although the positive role of the passivant molecule is not yet delineated. (2) Modulus of rupture tests on limestone cores treated with an aminoalkylsilane (AEAPS) and A2** showed a 25-35% increase in strength compared to the untreated samples. (3) Environmental scanning electron microscopy of treated limestone subjected to a concentrated acid attack showed degradation of the surface except in areas where thick layers of the consolidant were deposited.

  20. Surface degradation of polymer insulators under accelerated climatic aging in weather-ometer

    SciTech Connect

    Xu, G.; McGrath, P.B.; Burns, C.W.

    1996-12-31

    Climatic aging experiments were conducted on two types of outdoor polymer insulators by using a programmable weather-ometer. The housing materials for the insulators were silicone rubber (SR) and ethylene propylene diene monomer (EPDM). The accelerated aging stresses were comprised of ultraviolet radiation, elevated temperature, temperature cycling, thermal shock and high humidity. Their effects on the insulator surface conditions and electrical performance wee examined through visual inspection and SEM studies, contact angle measurements, thermogravimetric analysis (TGA), energy dispersive spectroscopy (EDS) analysis, and 50% impulse flashover voltage tests. The results showed a significant damage on the insulator surface caused by some of the imposed aging stresses. The EDS analysis suggested a photooxidation process that happened on the insulator surface during the aging period.

  1. Space Weather Monitoring for ISS Space Environments Engineering and Crew Auroral Observations

    NASA Technical Reports Server (NTRS)

    Minow, Joseph I.; Pettit, Donald R.; Hartman, William A.

    2012-01-01

    The awareness of potentially significant impacts of space weather on spaceand ground ]based technological systems has generated a strong desire in many sectors of government and industry to effectively transform knowledge and understanding of the variable space environment into useful tools and applications for use by those entities responsible for systems that may be vulnerable to space weather impacts. Essentially, effectively transitioning science knowledge to useful applications relevant to space weather has become important. This talk will present proven methodologies that have been demonstrated to be effective, and how in the current environment those can be applied to space weather transition efforts.

  2. How much does weather-driven vegetation dynamics matter in land surface modelling?

    NASA Astrophysics Data System (ADS)

    Ingwersen, Joachim; Streck, Thilo

    2016-04-01

    Land surface models (LSM) are an essential part of weather and climate models as they provide the lower boundary condition for the atmospheric models. In state-of-the-art LSMs the seasonal vegetation dynamics is "frozen". The seasonal variation of vegetation state variables, such as leaf area index or green vegetation fraction, are prescribed in lookup tables. Hence, a year-by-year variation in the development of vegetation due to changing weather conditions cannot be considered. For climate simulations, this is obviously a severe drawback. The objective of the present study was to quantify the potential error in the simulation of land surface exchange processes resulting from "frozen" vegetation dynamics. For this purpose we simulated energy and water fluxes from a winter wheat stand and a maize stand in Southwest Germany. In a first set of simulations, six years (2010 to 2015) were simulated considering weather-driven vegetation dynamics. For this purpose, we coupled the generic crop growth model GECROS with the NOAH-MP model (NOAHMP-GECROS). In a second set of simulations all vegetation-related state variables of the 2010 simulation were written to an external file and were used to overwrite the vegetation-related state variables of the simulations of the years 2011-2015. The difference between both sets was taken as a measure for the potential error introduced to the LSM due to the assumption of a "frozen" vegetation dynamics. We will present first results and discuss the impact of "frozen" vegetation dynamics on climate change simulations.

  3. An observational analysis: Tropical relative to Arctic influence on midlatitude weather in the era of Arctic amplification

    NASA Astrophysics Data System (ADS)

    Cohen, Judah

    2016-05-01

    The tropics, in general, and El Niño/Southern Oscillation (ENSO) in particular are almost exclusively relied upon for seasonal forecasting. Much less considered and certainly more controversial is the idea that Arctic variability is influencing midlatitude weather. However, since the late 1980s and early 1990s, the Arctic has undergone the most rapid warming observed globally, referred to as Arctic amplification (AA), which has coincided with an observed increase in extreme weather. Analysis of observed trends in hemispheric circulation over the period of AA more closely resembles variability associated with Arctic boundary forcings than with tropical forcing. Furthermore, analysis of intraseasonal temperature variability shows that the cooling in midlatitude winter temperatures has been accompanied by an increase in temperature variability and not a decrease, popularly referred to as "weather whiplash."

  4. Assimilating QuikSCAT Ocean Surface Winds with the Weather Research and Forecasting Model for Surface Wind-Field Simulation over the Chukchi/Beaufort Seas

    NASA Astrophysics Data System (ADS)

    Fan, Xingang; Krieger, Jeremy R.; Zhang, Jing; Zhang, Xiangdong

    2013-07-01

    To achieve a high-quality simulation of the surface wind field in the Chukchi/Beaufort Sea region, quick scatterometer (QuikSCAT) ocean surface winds were assimilated into the mesoscale Weather Research and Forecasting model by using its three-dimensional variational data assimilation system. The SeaWinds instrument on board the polar-orbiting QuikSCAT satellite is a specialized radar that measures ice-free ocean surface wind speed and direction at a horizontal resolution of 12.5 km. A total of eight assimilation case studies over two five-day periods, 1-5 October 2002 and 20-24 September 2004, were performed. The simulation results with and without the assimilation of QuikSCAT winds were then compared with QuikSCAT data available during the subsequent free-forecast period, coastal station observations, and North American Regional Reanalysis data. It was found that QuikSCAT winds are a potentially valuable resource for improving the simulation of ocean near-surface winds in the Chukchi/Beaufort Seas region. Specifically, the assimilation of QuikSCAT winds improved, (1) offshore surface winds as compared to unassimilated QuikSCAT winds, (2) sea-level pressure, planetary boundary-layer height, as well as surface heat fluxes, and (3) low-level wind fields and geopotential height. Verification against QuikSCAT data also demonstrated the temporal consistency and good quality of QuikSCAT observations.

  5. Homogenizing surface pressure time-series from operational numerical weather prediction models for geodetic applications

    NASA Astrophysics Data System (ADS)

    Dobslaw, H.

    2016-07-01

    Global surface pressure grids from 14.5 years of 6-hourly analyses out of both the operational ECMWF weather prediction model and ERA-Interim are mapped to a common reference orography by means of ECMWF's mean sea-level pressure diagnostic. The approach reduces both relative biases and residual variability by about one order of magnitude and thereby achieves a consistency among both data sets at the level of about 1 hPa. Remaining differences rather reflect temperature biases and also resolution limitations of the reanalysis data set, but are not anymore related to the local roughness in orography or to changes in the spatial resolution of the operational model. The presented reduction method therefore allows to obtain surface pressure time series with the long-time consistency of a reanalysis from an operational numerical weather model with much higher resolution and much shorter latency, making the results suitable for geodetic near realtime applications requiring continuously updated time series that are homogeneous over many years.

  6. Space Weathering Effects in Lunar Soils: The Roles of Surface Exposure Time and Bulk Chemical Composition

    NASA Technical Reports Server (NTRS)

    Zhang, Shouliang; Keller, Lindsay P.

    2011-01-01

    Space weathering effects on lunar soil grains result from both radiation-damaged and deposited layers on grain surfaces. Typically, solar wind irradiation forms an amorphous layer on regolith silicate grains, and induces the formation of surficial metallic Fe in Fe-bearing minerals [1,2]. Impacts into the lunar regolith generate high temperature melts and vapor. The vapor component is largely deposited on the surfaces of lunar soil grains [3] as is a fraction of the melt [4, this work]. Both the vapor-deposits and the deposited melt typically contain nanophase Fe metal particles (npFe0) as abundant inclusions. The development of these rims and the abundance of the npFe0 in lunar regolith, and thus the optical properties, vary with the soil mineralogy and the length of time the soil grains have been exposed to space weathering effects [5]. In this study, we used the density of solar flare particle tracks in soil grains to estimate exposure times for individual grains and then perform nanometer-scale characterization of the rims using transmission electron microscopy (TEM). The work involved study of lunar soil samples with different mineralogy (mare vs. highland) and different exposure times (mature vs. immature).

  7. The main pillar: Assessment of space weather observational asset performance supporting nowcasting, forecasting, and research to operations

    PubMed Central

    Posner, A; Hesse, M; St Cyr, O C

    2014-01-01

    Space weather forecasting critically depends upon availability of timely and reliable observational data. It is therefore particularly important to understand how existing and newly planned observational assets perform during periods of severe space weather. Extreme space weather creates challenging conditions under which instrumentation and spacecraft may be impeded or in which parameters reach values that are outside the nominal observational range. This paper analyzes existing and upcoming observational capabilities for forecasting, and discusses how the findings may impact space weather research and its transition to operations. A single limitation to the assessment is lack of information provided to us on radiation monitor performance, which caused us not to fully assess (i.e., not assess short term) radiation storm forecasting. The assessment finds that at least two widely spaced coronagraphs including L4 would provide reliability for Earth-bound CMEs. Furthermore, all magnetic field measurements assessed fully meet requirements. However, with current or even with near term new assets in place, in the worst-case scenario there could be a near-complete lack of key near-real-time solar wind plasma data of severe disturbances heading toward and impacting Earth's magnetosphere. Models that attempt to simulate the effects of these disturbances in near real time or with archival data require solar wind plasma observations as input. Moreover, the study finds that near-future observational assets will be less capable of advancing the understanding of extreme geomagnetic disturbances at Earth, which might make the resulting space weather models unsuitable for transition to operations. Key Points Manuscript assesses current and near-future space weather assets Current assets unreliable for forecasting of severe geomagnetic storms Near-future assets will not improve the situation PMID:26213516

  8. Quantifying the VNIR Effects of Nanophase Iron Generated through the Space Weathering of Silicates: Reconciling Modeled Data with Laboratory Observations

    NASA Astrophysics Data System (ADS)

    Legett, C., IV; Glotch, T. D.; Lucey, P. G.

    2015-12-01

    Space weathering is a diverse set of processes that occur on the surfaces of airless bodies due to exposure to the space environment. One of the effects of space weathering is the generation of nanophase iron particles in glassy rims on mineral grains due to sputtering of iron-bearing minerals. These particles have a size-dependent effect on visible and near infrared (VNIR) reflectance spectra with smaller diameter particles (< 50 nm) causing both reddening and darkening of the spectra with respect to unweathered material (Britt-Pieters particle behavior), while larger particles (> 300 nm) darken without reddening. Between these two sizes, a gradual shift between these two behaviors occurs. In this work, we present results from the Multiple Sphere T-Matrix (MSTM) scattering model in combination with Hapke theory to explore the particle size and iron content parameter spaces with respect to VNIR (700-1700 nm) spectral slope. Previous work has shown that the MSTM-Hapke hybrid model offers improvements over Mie-Hapke models. Virtual particles are constructed out of an arbitrary number of spheres, and each sphere is assigned a refractive index and extinction coefficient for each wavelength of interest. The model then directly solves Maxwell's Equations at every wave-particle interface to predict the scattering, extinction and absorption efficiencies. These are then put into a simplified Hapke bidirectional reflectance model that yields a predicted reflectance. Preliminary results show an area of maximum slopes for iron particle diameters < 80 nm and iron concentrations of ~1-10wt% in an amorphous silica matrix. Further model runs are planned to better refine the extent of this region. Companion laboratory work using mixtures of powdered aerogel and nanophase iron particles provides a point of comparison to modeling efforts. The effects on reflectance and emissivity values due to particle size in a nearly ideal scatterer (aerogel) are also observed with comparisons to

  9. Development of Innovative Technology to Provide Low-Cost Surface Atmospheric Observations

    NASA Astrophysics Data System (ADS)

    Kucera, Paul; Steinson, Martin

    2016-04-01

    Accurate and reliable real-time monitoring and dissemination of observations of surface weather conditions is critical for a variety of societal applications. Applications that provide local and regional information about temperature, precipitation, moisture, and winds, for example, are important for agriculture, water resource monitoring, health, and monitoring of hazard weather conditions. In many regions in Africa (and other global locations), surface weather stations are sparsely located and/or of poor quality. Existing stations have often been sited incorrectly, not well-maintained, and have limited communications established at the site for real-time monitoring. The US National Weather Service (NWS) International Activities Office (IAO) in partnership with University Corporation for Atmospheric Research (UCAR)/National Center for Atmospheric Research (NCAR) and funded by the United States Agency for International Development (USAID) Office of Foreign Disaster Assistance (OFDA) has started an initiative to develop and deploy low-cost weather instrumentation in sparsely observed regions of the world. The goal is to provide observations for environmental monitoring, and early warning alert systems that can be deployed at weather services in developing countries. Instrumentation is being designed using innovative new technologies such as 3D printers, Raspberry Pi computing systems, and wireless communications. The initial effort is focused on designing a surface network using GIS-based tools, deploying an initial network in Zambia, and providing training to Zambia Meteorological Department (ZMD) staff. The presentation will provide an overview of the project concepts, design of the low cost instrumentation, and initial experiences deploying a surface network deployment in Zambia.

  10. Inference of Surface Chemical and Physical Properties Using Mid-Infrared (MIR) Spectral Observations

    NASA Technical Reports Server (NTRS)

    Roush, Ted L.

    2016-01-01

    Reflected or emitted energy from solid surfaces in the solar system can provide insight into thermo-physical and chemical properties of the surface materials. Measurements have been obtained from instruments located on Earth-based telescopes and carried on several space missions. The characteristic spectral features commonly observed in Mid-Infrared (MIR) spectra of minerals will be reviewed, along with methods used for compositional interpretations of MIR emission spectra. The influence of surface grain size, and space weathering processes on MIR emissivity spectra will also be discussed. Methods used for estimating surface temperature, emissivity, and thermal inertias from MIR spectral observations will be reviewed.

  11. Simulating sulfur loss from asteroid surfaces as a result of space weathering

    NASA Astrophysics Data System (ADS)

    Kracher, A.; Sears, D.

    2003-04-01

    The NEAR Shoemaker spacecraft has found a lower than expected S/Si ratio on the surface of asteroid 433 Eros. Given that other element ratios are approximately chondritic, and that all known chondrite groups have S/Si ratio at least 3-10x higher than the NEAR data, it is unlikely that the low S abundance is a bulk property of Eros. Thus sulfur has apparently been lost from at least the top layer of the regolith. Possible sources for the energy required to either remove sulfur or transport it to deeper levels of the regolith are meteorite impact or solar wind exposure, or both. These phenomena are known to cause physical and chemical changes to lunar surface materials and are thought by some researchers to also occur on asteroids and to be responsible for the changes in asteroid spectra. The process is referred to as "space weathering". The effects of space weathering have been successfully simulated by exposure of regolith simulants to laser irradiation (simulating impacts) and ion beams (for solar wind). These experiments demonstrated the formation of submicroscopic Fe metal due to decomposition of Fe-bearing silicates. However, simulants used to date did not contain sulfide, an important constituent of chondrite meteorites and presumably asteroids. In sulfide-bearing regoliths decomposition of FeS as well as FeO would be expected. Experiments with sulfide-bearing simulants could shed light on the processes responsible for the low S/Si ratio on the surface of Eros. However, simulations of sulfur loss require more than simply performing the same experiments with a different simulant. The conditions of energy deposition have to be carefully adjusted so that they are a realistic proxy for the actual processes on asteroid surfaces. Also, the effects of regolith reworking need to be taken into account, since larger impacts can excavate deeper layers of regolith that were previously shielded from the effects of space weathering. Thus realistic simulations need to be

  12. An observed connection between wintertime temperature anomalies over Northwest China and weather regime transitions in North Atlantic

    NASA Astrophysics Data System (ADS)

    Li, Chao; Zhang, Qingyun

    2015-04-01

    In this study, the association between wintertime temperature anomalies over Northwest China and the weather regime transitions in North Atlantic on synoptic scale is analyzed by using observational surface air temperature (SAT) data and atmospheric reanalysis data. Daily SAT anomaly and duration time are used in order to define SAT anomaly cases. Differences with regard to the circulation anomalies over the Ural Mountains and the upstream North Atlantic area are evident. It is found that the colder than normal SAT is caused by the enhanced Ural high and associated southward flow over Northwest China. Time-lagged composites reveal possible connections between the SAT anomalies and the different development phases of the North Atlantic Oscillation (NAO). The Ural highs tend to be strengthened during the negative phase of NAO (NAO-) to Atlantic ridge transition, which are closely related to the downstream-propagating Rossby wave activity. The opposite circulation patterns are observed in the warm SAT cases. A cyclonic circulation anomaly is distinctly enhanced over the Urals during the positive phase of NAO (NAO+) to Scandinavian blocking transition, which would cause warmer SAT over Northwest China. Further analyses suggest that the intensified zonal wind over North Atlantic would favor the NAO- to Atlantic ridge transition, while the weakened zonal wind may be responsible for the transition between NAO+ and Scandinavian blocking.

  13. Oscillation Responses to an Extreme Weather Event from a Deep Moored Observing System

    NASA Astrophysics Data System (ADS)

    Wang, Z.; Dimarco, S. F.; Stoessel, M. M.; Zhang, X.; Ingle, S.

    2011-12-01

    In June 2007 tropical Cyclone Gonu passed directly over an ocean observing system consisting of four, deep autonomous mooring stations along the 3000 m isobath in the northern Arabian Sea. Gonu was the largest cyclone known to have occurred in the Arabian Sea or to strike the Arabian Peninsula. The mooring system was designed by Lighthouse R & D Enterprises, Inc. and installed in cooperation with the Oman Ministry of Agriculture and Fisheries Wealth. The instruments on the moorings continuously recorded water velocities, temperature, conductivity, pressure, dissolved oxygen and turbidity at multiple depths and at hourly intervals during the storm. Near-inertial oscillations at all moorings from thermocline to seafloor are coincident with the arrival of Gonu. Sub-inertial oscillations with periods of 2-10 days are recorded at the post-storm relaxation stage of Gonu, primarily in the thermocline. These oscillations consist of warm, saline water masses, likely originating from the Persian Gulf. Prominent 12.7-day sub-inertial waves, measured at a station ~300 km offshore, are bottom-intensified and have characteristics of baroclinic, topographically-trapped waves. Theoretical results from a topographically-trapped wave model are in a good agreement with the observed 12.7-day waves. The wavelength of the 12.7-day waves is about 590 km calculated from the dispersion relationship. Further analysis suggests that a resonant standing wave is responsible for trapping the 12.7-day wave energy inside the Sea of Oman basin. The observational results reported here are the first measurements of deepwater responses to a tropical cyclone in the Sea of Oman/Arabian Sea. Our study demonstrates the utility of sustained monitoring for studying the impact of extreme weather events on the ocean.

  14. Modification of olivine surface morphology and reactivity by microbial activity during chemical weathering

    NASA Astrophysics Data System (ADS)

    Welch, Susan A.; Banfield, Jillian F.

    2002-01-01

    Prior transmission electron microscope studies showed that the surface geometry of olivine changes dramatically during natural chemical weathering. However, similar morphological evolution has not been reported in laboratory studies of olivine dissolution. In this study, we examined the development of fayalite (Fe 2SiO 4) surface morphology during both abiotic and biotic (using Acidithiobacillus ferrooxidans) laboratory dissolution experiments at an initial pH of 2.0. The fayalite came from Cheyenne Canyon, Colorado (Smithsonian # R 3516) and contains a few percent laihunite (olivine structure with ordered ferric iron and vacancies, ˜Fe 0.82+Fe 0.83+SiO 4). High-resolution field emission low voltage scanning electron microscope (SEM) characterization of all reacted samples showed etch patterns consistent with those reported from naturally reacted olivine. High-resolution transmission electron microscope (HRTEM) data demonstrated pervasive channeling on (001), with channel spacings that range down to < 10 nm. Formation of channels on (001) is probably initiated by preferential removal of cations from olivine M1 sites. Channeling confers at least an order of magnitude increase in surface area. Relict strips of olivine between channels contain laihunite layers that are oriented parallel to channel margins. X-ray diffraction analyses indicated that the relative abundance of laihunite is higher in reacted compared to unreacted samples. This result is consistent with prior studies of naturally weathered olivine that suggest that laihunite is far less readily dissolved than olivine. Samples reacted in the presence of A. ferrooxidans cells that enzymatically oxidized iron, or in solutions where ferric iron was added to simulate biological activity, dissolve at a much slower rate than samples reacted abiotically. We attribute suppression of the olivine dissolution rate to surface adsorption of Fe 3+. It is probable that ferric iron adsorption is controlled by M2 sites in

  15. Impact of the winter North-Atlantic weather regimes on subtropical sea-surface height variability

    NASA Astrophysics Data System (ADS)

    Barrier, Nicolas; Treguier, Anne-Marie; Cassou, Christophe; Deshayes, Julie

    2013-09-01

    Interannual variability of subtropical sea-surface-height (SSH) anomalies, estimated by satellite and tide-gauge data, is investigated in relation to wintertime daily North-Atlantic weather regimes. Sea-level anomalies can be viewed as proxies for the subtropical gyre intensity because of the intrinsic baroclinic structure of the circulation. Our results show that the strongest correlation between SSH and weather regimes is found with the so-called Atlantic-Ridge (AR) while no significant values are obtained for the other regimes, including those related to the North Atlantic Oscillation (NAO), known as the primary actor of the Atlantic dynamics. Wintertime AR events are characterized by anticyclonic wind anomalies off Europe leading to a northward shift of the climatological wind-stress curl. The latter affects subtropical SSH annual variability by altered Sverdrup balance and ocean Rossby wave dynamics propagating westward from the African coast towards the Caribbean. The use of a simple linear planetary geostrophic model allows to quantify those effects and confirms the primary importance of the winter season to explain the largest part of SSH interannual variability in the Atlantic subtropical gyre. Our results open new perspectives in the comprehension of North-Atlantic Ocean variability emphasizing the role of AR as a driver of interannual variability at least of comparable importance to NAO.

  16. Surface Temperature Variation Prediction Model Using Real-Time Weather Forecasts

    NASA Astrophysics Data System (ADS)

    Karimi, M.; Vant-Hull, B.; Nazari, R.; Khanbilvardi, R.

    2015-12-01

    Combination of climate change and urbanization are heating up cities and putting the lives of millions of people in danger. More than half of the world's total population resides in cities and urban centers. Cities are experiencing urban Heat Island (UHI) effect. Hotter days are associated with serious health impacts, heart attaches and respiratory and cardiovascular diseases. Densely populated cities like Manhattan, New York can be affected by UHI impact much more than less populated cities. Even though many studies have been focused on the impact of UHI and temperature changes between urban and rural air temperature, not many look at the temperature variations within a city. These studies mostly use remote sensing data or typical measurements collected by local meteorological station networks. Local meteorological measurements only have local coverage and cannot be used to study the impact of UHI in a city and remote sensing data such as MODIS, LANDSAT and ASTER have with very low resolution which cannot be used for the purpose of this study. Therefore, predicting surface temperature in urban cities using weather data can be useful.Three months of Field campaign in Manhattan were used to measure spatial and temporal temperature variations within an urban setting by placing 10 fixed sensors deployed to measure temperature, relative humidity and sunlight. Fixed instrument shelters containing relative humidity, temperature and illumination sensors were mounted on lampposts in ten different locations in Manhattan (Vant-Hull et al, 2014). The shelters were fixed 3-4 meters above the ground for the period of three months from June 23 to September 20th of 2013 making measurements with the interval of 3 minutes. These high resolution temperature measurements and three months of weather data were used to predict temperature variability from weather forecasts. This study shows that the amplitude of spatial and temporal variation in temperature for each day can be predicted

  17. Observing Global Surface Water Flood Dynamics

    NASA Astrophysics Data System (ADS)

    Bates, Paul D.; Neal, Jefferey C.; Alsdorf, Douglas; Schumann, Guy J.-P.

    2014-05-01

    Flood waves moving along river systems are both a key determinant of globally important biogeochemical and ecological processes and, at particular times and particular places, a major environmental hazard. In developed countries, sophisticated observing networks and ancillary data, such as channel bathymetry and floodplain terrain, exist with which to understand and model floods. However, at global scales, satellite data currently provide the only means of undertaking such studies. At present, there is no satellite mission dedicated to observing surface water dynamics and, therefore, surface water scientists make use of a range of sensors developed for other purposes that are distinctly sub-optimal for the task in hand. Nevertheless, by careful combination of the data available from topographic mapping, oceanographic, cryospheric and geodetic satellites, progress in understanding some of the world's major river, floodplain and wetland systems can be made. This paper reviews the surface water data sets available to hydrologists on a global scale and the recent progress made in the field. Further, the paper looks forward to the proposed NASA/CNES Surface Water Ocean Topography satellite mission that may for the first time provide an instrument that meets the needs of the hydrology community.

  18. Space Weather Measurements from the Surface of Mars with the RAD Instrument on the Mars Science Laboratory

    NASA Astrophysics Data System (ADS)

    Hassler, Donald M.; Rafkin, Scot; Reitz, Guenther; Koehler, Jan; Posner, Arik; Guo, Jingnan; Ehresmann, Bent; Zeitlin, Cary; Wimmer-Schweingruber, Robert; Matthiä, Daniel

    2016-07-01

    The Radiation Assessment Detector (RAD) is a compact, lightweight energetic particle analyzer currently operating on the surface of Mars as part of the Mars Science Laboratory (MSL) Mission. RAD is providing the first measurements of the energetic particle radiation environment on the surface of another planet due to solar flares, coronal mass ejections (CMEs), and galactic cosmic rays (GCRs). RAD is providing synoptic measurements of the energetic particle environment at a 2nd location in heliosphere (other than near-Earth or L1), and will aid heliospheric modeling over solar cycle. These observations of SEP fluxes are contributing to a solar energetic particle (SEP) event database at Mars and the Martian surface to aid prediction of Solar Particle Events (SPEs), including onset, temporal & size predictions. This presentation will provide an overview of the RAD investigation and present measurements of the solar flare, GCR and radiation environment on the surface of Mars, and discuss the importance of providing broad heliospheric coverage for situational awareness of space weather as we plan to send humans out into deep space and to Mars. RAD is supported by NASA (HEOMD) under JPL subcontract #1273039 to SwRI, and by DLR in Germany under contract with Christian-Albrechts-Universitat (CAU).

  19. Space Weather Measurements from the Surface of Mars with the RAD Instrument on the Mars Science Laboratory

    NASA Astrophysics Data System (ADS)

    Hassler, D.

    2015-12-01

    The Radiation Assessment Detector (RAD) is a compact, lightweight energetic particle analyzer currently operating on the surface of Mars as part of the Mars Science Laboratory (MSL) Mission. RAD is providing the first measurements of the energetic particle radiation environment on the surface of another planet due to solar flares, coronal mass ejections (CMEs), and galactic cosmic rays (GCRs). RAD is providing synoptic measurements of the energetic particle environment at a 2nd location in heliosphere (other than near-Earth or L1), and will aid heliospheric modeling over solar cycle. These observations of SEP fluxes are contributing to a solar energetic particle (SEP) event database at Mars and the Martian surface to aid prediction of Solar Particle Events (SPEs), including onset, temporal & size predictions. This presentation will provide an overview of the RAD investigation and present measurements of the solar flare, GCR and radiation environment on the surface of Mars, and discuss the importance of providing broad heliospheric coverage for situational awareness of space weather as we plan to send humans out into deep space and to Mars. RAD is supported by NASA (HEOMD) under JPL subcontract #1273039 to SwRI, and by DLR in Germany under contract with Christian-Albrechts-Universitat (CAU).

  20. Weather Instruments.

    ERIC Educational Resources Information Center

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

    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…

  1. Statistical relationship between surface PM10 concentration and aerosol optical depth over the Sahel as a function of weather type, using neural network methodology

    NASA Astrophysics Data System (ADS)

    Yahi, H.; Marticorena, B.; Thiria, S.; Chatenet, B.; Schmechtig, C.; Rajot, J. L.; Crepon, M.

    2013-12-01

    work aims at assessing the capability of passive remote-sensed measurements such as aerosol optical depth (AOD) to monitor the surface dust concentration during the dry season in the Sahel region (West Africa). We processed continuous measurements of AODs and surface concentrations for the period (2006-2010) in Banizoumbou (Niger) and Cinzana (Mali). In order to account for the influence of meteorological condition on the relationship between PM10 surface concentration and AOD, we decomposed the mesoscale meteorological fields surrounding the stations into five weather types having similar 3-dimensional atmospheric characteristics. This classification was obtained by a clustering method based on nonlinear artificial neural networks, the so-called self-organizing map. The weather types were identified by processing tridimensional fields of meridional and zonal winds and air temperature obtained from European Centre for Medium-Range Weather Forecasts (ECMWF) model output centered on each measurement station. Five similar weather types have been identified at the two stations. Three of them are associated with the Harmattan flux; the other two correspond to northward inflow of the monsoon flow at the beginning or the end of the dry season. An improved relationship has been found between the surface PM10 concentrations and the AOD by using a dedicated statistical relationship for each weather type. The performances of the statistical inversion computed on the test data sets show satisfactory skills for most of the classes, much better than a linear regression. This should permit the inversion of the mineral dust concentration from AODs derived from satellite observations over the Sahel.

  2. The Main Pillar: Assessment of Space Weather Observational Asset Performance Supporting Nowcasting, Forecasting and Research to Operations

    NASA Technical Reports Server (NTRS)

    Posner, Arik; Hesse, Michael; SaintCyr, Chris

    2014-01-01

    Space weather forecasting critically depends upon availability of timely and reliable observational data. It is therefore particularly important to understand how existing and newly planned observational assets perform during periods of severe space weather. Extreme space weather creates challenging conditions under which instrumentation and spacecraft may be impeded or in which parameters reach values that are outside the nominal observational range. This paper analyzes existing and upcoming observational capabilities for forecasting, and discusses how the findings may impact space weather research and its transition to operations. A single limitation to the assessment is lack of information provided to us on radiation monitor performance, which caused us not to fully assess (i.e., not assess short term) radiation storm forecasting. The assessment finds that at least two widely spaced coronagraphs including L4 would provide reliability for Earth-bound CMEs. Furthermore, all magnetic field measurements assessed fully meet requirements. However, with current or even with near term new assets in place, in the worst-case scenario there could be a near-complete lack of key near-real-time solar wind plasma data of severe disturbances heading toward and impacting Earth's magnetosphere. Models that attempt to simulate the effects of these disturbances in near real time or with archival data require solar wind plasma observations as input. Moreover, the study finds that near-future observational assets will be less capable of advancing the understanding of extreme geomagnetic disturbances at Earth, which might make the resulting space weather models unsuitable for transition to operations.

  3. eHeroes and Swiff: EC-Funded FP7 networks for modelling and observation of space weather events

    NASA Astrophysics Data System (ADS)

    Lapenta, Giovanni

    2013-04-01

    We report on two EC-FP7 funded projects: Swiff and eHeroes. Swiff (swiff.eu) is a modelling effort that aims at producing an integrated space weather modelling and forecasting network. We are unifying into a single approach fluid and kinetic models to track space weather events from their solar origin to their impact on the Earth environment, eHeores (eheroes.eu) is a observational and modelling effort that collects and processes data to produce new data services and new models to track and predict space weather. eHeores focuses on the impact of space weather on space exploration including the effects on spacecraft, on the exploration of the Moon and Mars. We will report on the results obtained in these projects highlighting their relevance to space weather and its impact on the Earth and on space exploration. The research leading to these results has received funding from the European Commission's Seventh Framework Programme (FP7/2007-2013) under the grant agreement SWIFF (project n° 263340, www.swiff.eu).

  4. Daymet: Daily Surface Weather Data on a 1-km Grid for North America, Version 2.

    SciTech Connect

    Thornton, Peter E; Thornton, Michele M; Mayer, Benjamin W; Wilhelmi, Nate; Wei, Yaxing; Devarakonda, Ranjeet; Cook, Robert B

    2014-01-01

    More information: http://daymet.ornl.gov Presenter: Ranjeet Devarakonda Environmental Sciences Division Oak Ridge National Laboratory (ORNL) Daymet: Daily Surface Weather Data and Climatological Summaries provides gridded estimates of daily weather parameters for North America, including daily continuous surfaces of minimum and maximum temperature, precipitation occurrence and amount, humidity, shortwave radiation, snow water equivalent, and day length. The current data product (Version 2) covers the period January 1, 1980 to December 31, 2013 [1]. The prior product (Version 1) only covered from 1980-2008. Data are available on a daily time step at a 1-km x 1-km spatial resolution in Lambert Conformal Conic projection with a spatial extent that covers the conterminous United States, Mexico, and Southern Canada as meteorological station density allows. Daymet data can be downloaded from 1) the ORNL Distributed Active Archive Center (DAAC) search and order tools (http://daac.ornl.gov/cgi-bin/cart/add2cart.pl?add=1219) or directly from the DAAC FTP site (http://daac.ornl.gov/cgi-bin/dsviewer.pl?ds_id=1219) and 2) the Single Pixel Tool [2] and THREDDS (Thematic Real-time Environmental Data Services) Data Server [3]. The Single Pixel Data Extraction Tool allows users to enter a single geographic point by latitude and longitude in decimal degrees. A routine is executed that translates the (lon, lat) coordinates into projected Daymet (x,y) coordinates. These coordinates are used to access the Daymet database of daily-interpolated surface weather variables. Daily data from the nearest 1 km x 1 km Daymet grid cell are extracted from the database and formatted as a table with one column for each Daymet variable and one row for each day. All daily data for selected years are returned as a single (long) table, formatted for display in the browser window. At the top of this table is a link to the same data in a simple comma-separated text format, suitable for import into a

  5. Weather in the News.

    ERIC Educational Resources Information Center

    Markle, Sandra

    1989-01-01

    A discussion of TV weather forecasting introduces this article which features several hands-on science activities involving observing, researching, and experimenting with the weather. A reproducible worksheet on the reliability of weather forecasts is included. (IAH)

  6. Observation and research for strong meteor shower and related catastrophic space weather

    NASA Astrophysics Data System (ADS)

    Ma, Y. H.; He, Y. W.; Xu, P. X.; Zhao, H. B.

    2007-07-01

    During the first international joint observation for strong meteor shower, we made multi-subject observations for Leonids and Draconids and their disaster space weather events by several methods. Combining the synthetical analysis of Leonids, Perseids and Draconids and their related data from 1957 to 2003, we sufficiently confirm that the periodic strong meteor showers can result in the formation of catastrophic space weather events. The following summing-up is confirmed basically: 1.The formation mechanism of the strong meteor shower There are meteoroids with high density and uneven distribution close the cometary nucleus, especially in the direction of opposite the Sun and backside of the nucleus. They can stretch 1-11AU along the cometary orbit and 1-5 (&sim10^3AU) cross the orbit. Therefore good displays of meteor shower (10---100 times as usual) or storms (103---104 times as usual) can occur when the Earth passes a high density meteoroid stream during the period of 3 years before and 5 years after the perihelion passage of the comet. During that period, bolides or shooting stars which are serious harmful to spaceflight security increase greatly to 3%~10%. This corrects the wrong point of view that the harmful micro-meteoroids to spaceflight security in period meteor showers are <1 g only. 2. The cosmic dust maintaining mechanism of long-life Es layer in mid-latitude area It is proved the life of Es layer increased greatly when most ions are long-life metal type ions (Fe +, Mg + ?? ) which composite coefficient is much smaller than that of molecule type ions(O2 + , NO + ?? ). The observation for about 50 years roughly approves that the blanketing frequency of Es layer (fb Es) abnormally increase in large area (>105km2) and lasting long time (>15 min) only when strong meteor shower occurred at night. It is not f, l and c type Es layer evolved from sequence Es layer. This shows that the cause of fb Es increase is that the ionosphere was bombarded by an additional

  7. Oxidative Weathering of Earth's Surface 3.7 Billion Years ago? - A Chromium Isotope Perspective

    NASA Astrophysics Data System (ADS)

    Frei, R.; Crowe, S.; Bau, M.; Polat, A.; Fowle, D. A.; Døssing, L. N.

    2015-12-01

    The Great Oxidation Event signals the first large-scale oxygenation of the atmosphere roughly 2.4 Gyr ago. Geochemical signals diagnostic of oxidative weathering, however, extend as far back as 3.3-2.9 Gyr ago. 3.8-3.7 Gyr old rocks from Isua, Greenland stand as a deep time outpost, recording information on Earth's earliest surface chemistry and the low oxygen primordial biosphere. We find positive Cr isotope values (average δ53Cr = +0.05 +/- 0.10 permil; δ53Cr = (53Cr/52Cr)sample/(53Cr/52Cr)SRM 979 - 1) x 1000, where SRM 979 denotes Standard Reference Material 979 in both the Fe and Si-rich mesobands of 7 compositionally distinct quartz-magnetite and magnesian banded iron formation (BIF) samples collected from the eastern portion of the Isua BIF (Western Greenland). These postively fractioned Cr isotopes, relative to the igneous silicate Earth reservoir, in metamorphosed BIFs from Isua indicate oxidative Cr cycling 3.8-3.7 Gyr ago. We also examined the distribution of U, which is immobile in its reduced state but mobile when it is oxidized. Elevated U/Th ratios (mean U/Th ratio of 0.70 ± 0.29) in these BIFs relative to the contemporary crust, also signal oxidative mobilization of U. We suggest that reactive oxygen species (ROS) accumulated in Earth's surface environment inducing the oxidative weathering of rocks during the deposition of the Isua BIFs. The precise threshold atmospheric O2 concentrations for the induction of Cr isotope fractionation remain uncertain, but we argue that our data are consistent with the very low levels of oxygen or other ROS indicated by other proxies. Importantly, any trace of Cr that cycled through redox reactions on land would tend both to be heavy, and to mobilize into the contemporaneous run-off more readily than Cr weathered directly as Cr(III). Once having reached the oceans, this fractionated Cr would have been stripped from seawater by Fe (oxy)hydroxides formed during the deposition of BIFs from low oxygen oceans. The

  8. Sensitivity of Spacebased Microwave Radiometer Observations to Ocean Surface Evaporation

    NASA Technical Reports Server (NTRS)

    Liu, Timothy W.; Li, Li

    2000-01-01

    Ocean surface evaporation and the latent heat it carries are the major components of the hydrologic and thermal forcing on the global oceans. However, there is practically no direct in situ measurements. Evaporation estimated from bulk parameterization methods depends on the quality and distribution of volunteer-ship reports which are far less than satisfactory. The only way to monitor evaporation with sufficient temporal and spatial resolutions to study global environment changes is by spaceborne sensors. The estimation of seasonal-to-interannual variation of ocean evaporation, using spacebased measurements of wind speed, sea surface temperature (SST), and integrated water vapor, through bulk parameterization method,s was achieved with reasonable success over most of the global ocean, in the past decade. Because all the three geophysical parameters can be retrieved from the radiance at the frequencies measured by the Scanning Multichannel Microwave Radiometer (SMMR) on Nimbus-7, the feasibility of retrieving evaporation directly from the measured radiance was suggested and demonstrated using coincident brightness temperatures observed by SMMR and latent heat flux computed from ship data, in the monthly time scale. However, the operational microwave radiometers that followed SMMR, the Special Sensor Microwave/Imager (SSM/I), lack the low frequency channels which are sensitive to SST. This low frequency channels are again included in the microwave imager (TMI) of the recently launched Tropical Rain Measuring Mission (TRMM). The radiance at the frequencies observed by both TMI and SSM/I were simulated through an atmospheric radiative transfer model using ocean surface parameters and atmospheric temperature and humidity profiles produced by the reanalysis of the European Center for Medium Range Weather Forecast (ECMWF). From the same ECMWF data set, coincident evaporation is computed using a surface layer turbulent transfer model. The sensitivity of the radiance to

  9. Observation of local cloud and moisture feedbacks over high ocean and desert surface temperatures

    NASA Technical Reports Server (NTRS)

    Chahine, Moustafa T.

    1995-01-01

    New data on clouds and moisture, made possible by reanalysis of weather satellite observations, show that the atmosphere reacts to warm clusters of very high sea surface temperatures in the western Pacific Ocean with increased moisture, cloudiness, and convection, suggesting a negative feedback limiting the sea surface temperature rise. The reverse was observed over dry and hot deserts where both moisture and cloudiness decrease, suggesting a positive feedback perpetuating existing desert conditions. In addition, the observations show a common critical surface temperature for both oceans and land; the distribution of atmospheric moisture is observed to reach a maximum value when the daily surface temperatures approach 304 +/- 1 K. These observations reveal complex dynamic-radiative interactions where multiple processes act simultaneously at the surface as well as in the atmosphere to regulate the feedback processes.

  10. Global surface-based cloud observation for ISCCP

    NASA Technical Reports Server (NTRS)

    1994-01-01

    Visual observations of cloud cover are hindered at night due to inadequate illumination of the clouds. This usually leads to an underestimation of the average cloud cover at night, especially for the amounts of middle and high clouds, in climatologies on surface observations. The diurnal cycles of cloud amounts, if based on all the surface observations, are therefore in error, but they can be obtained more accurately if the nighttime observations are screened to select those made under sufficient moonlight. Ten years of nighttime weather observations from the northern hemisphere in December were classified according to the illuminance of moonlight or twilight on the cloud tops, and a threshold level of illuminance was determined, above which the clouds are apparently detected adequately. This threshold corresponds to light from a full moon at an elevation angle of 6 degrees or from a partial moon at higher elevation, or twilight from the sun less than 9 degrees below the horizon. It permits the use of about 38% of the observations made with the sun below the horizon. The computed diurnal cycles of total cloud cover are altered considerably when this moonlight criterion is imposed. Maximum cloud cover over much of the ocean is now found to be at night or in the morning, whereas computations obtained without benefit of the moonlight criterion, as in our published atlases, showed the time of maximum to be noon or early afternoon in many regions. Cloud cover is greater at night than during the day over the open oceans far from the continents, particularly in summer. However, near noon maxima are still evident in the coastal regions, so that the global annual average oceanic cloud cover is still slightly greater during the day than at night, by 0.3%. Over land, where daytime maxima are still obtained but with reduced amplitude, average cloud cover is 3.3% greater during the daytime. The diurnal cycles of total cloud cover we obtain are compared with those of ISCCP for a

  11. Earth surface erosion and weathering from the 10Be (meteoric)/9Be ratio

    NASA Astrophysics Data System (ADS)

    von Blanckenburg, F.; Bouchez, J.; Wittmann, H.; Dannhaus, N.

    2012-12-01

    A perfect clock of the stability of the Earth surface is one that combines a first isotope the flux of which depends on the release rate during erosion, and a second isotope produced at constant rate. The ratio of the meteoric cosmogenic nuclide 10Be to stable 9Be is such a system. We provide a quantitative framework for its use. In a weathering zone some of the 9Be, present typically in 2.5ppm concentrations in silicate minerals, is released and partitioned between a reactive phase (adsorbed to clay and hydroxide surfaces, given the high partition coefficients at intermediate pH), and into the dissolved phase. The combined mass flux of both phases is defined by the soil formation rate and a mineral dissolution rate - and is hence proportional to the chemical weathering rate and the denudation rate. At the same time, the surface of the weathering zone is continuously exposed to fallout of meteoric 10Be. This 10Be percolates into the weathering zone where it mixes with dissolved 9Be. Both isotopes may exchange with the adsorbed Be, given that equilibration rate of Be is fast relative to soil residence times. Hence a 10Be/9Be(reactive) ratio results in soils from which the total denudation rate can be calculated. A prerequisite is that the flux of meteoric 10Be is known from field experiments or from global production models [1], that the 9Be concentration in bedrock (mostly 2.5ppm) is known [2], and that the reactive Be can be chemically extracted from soil or sediment [3]. In rivers, when reactive Be and dissolved Be equilibrate, a catchment-wide denudation rate can be determined from both sediment and a sample of filtered river water, where the sediment 10Be/9Be ratio is independent of grain size. We have tested this approach in sediment-bound Be and dissolved Be in water of the Amazon and Orinoco basin. The reactive Be was extracted from sediment by combined hydroxylamine and HCl leaches [2]. In the Amazon trunk stream, the Orinoco, Apure, and La Tigra river 10Be

  12. GEM: Statistical weather forecasting procedure

    NASA Technical Reports Server (NTRS)

    Miller, R. G.

    1983-01-01

    The objective of the Generalized Exponential Markov (GEM) Program was to develop a weather forecast guidance system that would: predict between 0 to 6 hours all elements in the airways observations; respond instantly to the latest observed conditions of the surface weather; process these observations at local sites on minicomputing equipment; exceed the accuracy of current persistence predictions at the shortest prediction of one hour and beyond; exceed the accuracy of current forecast model output statistics inside eight hours; and be capable of making predictions at one location for all locations where weather information is available.

  13. Surface dynamics of crude and weathered oil in the presence of dispersants: Laboratory experiment and numerical simulation

    NASA Astrophysics Data System (ADS)

    Soloviev, Alexander V.; Haus, Brian. K.; McGauley, Michael G.; Dean, Cayla W.; Ortiz-Suslow, David G.; Laxague, Nathan J. M.; Özgökmen, Tamay M.

    2016-05-01

    Marine oil spills can have dire consequences for the environment. Research on their dynamics is important for the well-being of coastal communities and their economies. Propagation of oil spills is a very complex physical-chemical process. As seen during the Deepwater Horizon event in the Gulf of Mexico during 2010, one of the critical problems remaining for prediction of oil transport and dispersion in the marine environment is the small-scale structure and dynamics of surface oil spills. The laboratory experiments conducted in this work were focused on understanding the differences between the dynamics of crude and weathered oil spills and the effect of dispersants. After deposition on the still water surface, a drop of crude oil quickly spread into a thin slick; while at the same time, a drop of machine (proxy for weathered) oil did not show significant evolution. Subsequent application of dispersant to the crude oil slick resulted in a quick contraction or fragmentation of the slick into narrow wedges and tiny drops. Notably, the slick of machine oil did not show significant change in size or topology after spraying dispersant. An advanced multi-phase, volume of fluid computational fluid dynamics model, incorporating capillary forces, was able to explain some of the features observed in the laboratory experiment. As a result of the laboratory and modeling experiments, the new interpretation of the effect of dispersant on the oil dispersion process including capillary effects has been proposed, which is expected to lead to improved oil spill models and response strategies.

  14. Surface Properties of Titan from Radar Observations

    NASA Astrophysics Data System (ADS)

    Campbell, D. B.; Black, G. J.; Margot, J.-L.; Nolan, M.; Ostro, S. J.; Slade, M.

    2000-10-01

    The 13 cm wavelength radar system on the 305 m Arecibo telescope was used in October and November, 1999 to observe Titan. Observations took place on nine nights spanning the whole range of Titan longitudes. A circularly polarized wave was transmitted and the backscatter cross section measured in both the expected or OC sense of receive circular polarization and in the cross polarized or SC sense. Initial reduction of the observations gave a mean OC cross section of 16% +/- 3 of Titan's projected area and a circular polarization ratio (the ratio of the SC to OC cross sections) of 0.6 +/- 0.2. The mean OC cross section is slightly higher than the 12.5% reported by Muhleman et al. (Ann. Rev. Earth Planet. Sci., 1995, Vol. 23) at 3.5 cm wavelength. The high polarization ratio is indicative of either a very rough surface at wavelength scales or, possibly, sub-surface multiple scattering. The 13 cm OC cross section varies between 6% and 24% as a function of longitude, a somewhat smaller range than that reported by Muhleman et al. at 3.5 cm. The Arecibo Observatory is part of the National Astronomy and Ionosphere Center which is operated by Cornell University under a cooperative agreement the National Science Foundation. Additional support is provided by NASA. DBC, SJO and MS were partially supported by NASA grants.

  15. Annual carbon dioxide cycle in a montane soil: observations, modeling, and implications for weathering

    SciTech Connect

    Solomon, D.K.; Cerling, T.E.

    1987-12-01

    Profiles of CO/sub 2/ concentrations in soil and snow, soil respiration, soil and snow temperatures, and shallow ground water chemistry were monitored from March 1984 to July 1985 in a montane region neat Brighton, Utah. Significant seasonal variations in the concentrations of CO/sub 2/ in soil and snow occurred, and two principal rise-decline cycles were observed. During the first cycle the concentration of soil CO/sub 2/ at 35 cm rose from 4200 ppmv in July to a maximum of 12,400 ppmv in August and then declined to 4300 ppmv by October. This cycle is attributed to the changing production rate of soil CO/sub 2/ during the growing season. During the second cycle the concentration of CO/sub 2/ at 35 cm began to rise in November, reached a maximum of 7200 ppmv in early spring, and quickly declined to 3200 ppmv by late spring shortly after the snow cover had melted. This cycle is attributed to deterioration in the exchange of CO/sub 2/ between the soil and atmosphere due to a deep snowpack. A model based on Fick's second law of diffusion was developed to account for the temporal and spatial distribution of soil CO/sub 2/. The model predicts that soil CO/sub 2/ at 35 cm is increased by as much as 15 times due to the deep snowpack. The elevated concentration of soil CO/sub 2/, abundance of water, and above-freezing soil temperatures imply that significant soil weathering occurs during the winter in montane regions.

  16. Satellite-observed sensitivity of weather condition for forecasting malaria vector distribution in Bandarban District, Bangladesh

    NASA Astrophysics Data System (ADS)

    Nizamuddin, Mohammad; Rahman, Atiqur; Roytman, Leonid; Kogan, Felix; Powell, Al; Goldberg, Mitch; Khan, Mohammad M.

    2008-10-01

    Malaria is a serious public health problem in Bangladesh. Almost thirteen districts in Bangladesh experience epidemics of malaria. Epidemics occur mainly in the highlands of Bangladesh, notably in Bandarban district. This study examined the relationship between environmental factors and malaria incidence in Bandarban district in Bangladesh. This paper examines the association between malaria cases and weekly vegetation health condition index for the region for last fourteen years. The vegetation health index derived from a combination of Advance Very High Resolution Radiometer based normalized difference vegetation index and 10 micrometer (μm) to 11 micrometer (μm) thermal radiances, was designed for monitoring moisture and thermal impacts on vegetation health. It estimates the correlation between malaria cases and Vegetation Health (VH) Indices (Vegetation Condition Index (VCI) and Temperature Condition Index (TCI)) computed for each week over a period of 14 years (1992-2005). Following the results of correlation analysis the principal components regression (PCR) method was performed on weather components of satellite data and climate variability during each of the two annual malaria seasons to construct a model to predict malaria as a function of the TCI computed for this period. A good correlation was found between malaria cases and TCI characterizing thermal condition during the month of August and September. Furthermore the simulated results found from PCR model were compared with observed malaria statistics showing that the error of the estimates of malaria is less than 10%. Remote sensing therefore demonstrates the potential of a seasonal forecasting which can provide information about peak mosquito to breading conditions. The derived results are potential important for decision makers in the region to control malaria particularly under constraint of limited budget allocations.

  17. The rate of chemical weathering of pyrite on the surface of Venus

    NASA Technical Reports Server (NTRS)

    Fegley, B., Jr.; Lodders, K.

    1993-01-01

    This abstract reports results of an experimental study of the chemical weathering of pyrite (FeS2) under Venus-like conditions. This work, which extends the earlier study by Fegley and Treiman, is part of a long range research program to experimentally measure the rates of thermochemical gas-solid reactions important in the atmospheric-lithospheric sulfur cycle on Venus. The objectives of this research are (1) to measure the kinetics of thermochemical gas-solid reactions responsible for both the production (e.g., anhydrite formation) and destruction (e.g., pyrrhotite oxidation) of sulfur-bearing minerals on the surface of Venus and (2) to incorporate these and other constraints into holistic models of the chemical interactions between the atmosphere and surface of Venus. Experiments were done with single crystal cubes of natural pyrite (Navajun, Logrono, Spain) that were cut and polished into slices of known weight and surface area. The slices were isothermally heated at atmospheric pressure in 99.99 percent CO2 (Coleman Instrument Grade) at either 412 C (685 K) or 465 C (738 K) for time periods up to 10 days. These two isotherms correspond to temperatures at about 6 km and 0 km altitude, respectively, on Venus. The reaction rate was determined by measuring the weight loss of the reacted slices after removal from the furnace. The reaction products were characterized by X-ray diffraction, scanning electron microscopy, and energy dispersive spectroscopy on the SEM.

  18. Improving the Long-Term Stability of Atmospheric Surface Deformation Predictions by Mitigating the Effects of Orography Updates in Operational Weather Forecast Models

    NASA Astrophysics Data System (ADS)

    Dill, Robert; Bergmann-Wolf, Inga; Thomas, Maik; Dobslaw, Henryk

    2016-04-01

    The global numerical weather prediction model routinely operated at the European Centre for Medium-Range Weather Forecasts (ECMWF) is typically updated about two times a year to incorporate the most recent improvements in the numerical scheme, the physical model or the data assimilation procedures into the system for steadily improving daily weather forecasting quality. Even though such changes frequently affect the long-term stability of meteorological quantities, data from the ECMWF deterministic model is often preferred over alternatively available atmospheric re-analyses due to both the availability of the data in near real-time and the substantially higher spatial resolution. However, global surface pressure time-series, which are crucial for the interpretation of geodetic observables, such as Earth rotation, surface deformation, and the Earth's gravity field, are in particular affected by changes in the surface orography of the model associated with every major change in horizontal resolution happened, e.g., in February 2006, January 2010, and May 2015 in case of the ECMWF operational model. In this contribution, we present an algorithm to harmonize surface pressure time-series from the operational ECMWF model by projecting them onto a time-invariant reference topography under consideration of the time-variable atmospheric density structure. The effectiveness of the method will be assessed globally in terms of pressure anomalies. In addition, we will discuss the impact of the method on predictions of crustal deformations based on ECMWF input, which have been recently made available by GFZ Potsdam.

  19. Lunar Surface Properties from Diviner Eclipse Observations

    NASA Astrophysics Data System (ADS)

    Hayne, Paul; Paige, David; Greenhagen, Benjamin; Bandfield, Joshua; Siegler, Matthew; Lucey, Paul

    2015-04-01

    The thermal behavior of planetary bodies can reveal information about fundamental processes shaping their surfaces and interiors. Diviner [1] has been mapping the Moon's diurnal temperatures since the Lunar Reconnaissance Orbiter (LRO) arrived in 2009, yielding new insights into regolith formation [2, 3], the distribution of volatiles [4, 5], lunar volcanism [6, 7, 8], and impact processes [9]. The Moon's cooling during eclipse provides complementary information on the physical properties of the uppermost surface layer, which can be used to further investigate these and other processes. We used data from Diviner's seven thermal infrared spectral channels to measure surface temperatures before, during and after the 8 Oct., 2014 eclipse. In its standard nadir-pushbroom mode, Diviner maps surface temperatures in a ~6-km swath with a spatial resolution of ~250 m. Using Diviner's independent scanning capability [11], we also targeted two regions of interest on sequential orbits to create a time series of thermal observations: 1) Kepler crater (-38°E, 8°N) and 2) an unnamed nighttime "cold spot" (-33.3°E, 3°N). Pre-eclipse surface temperatures in these regions were ~380 K. As a relatively young Copernican-aged impact crater, Kepler was selected to investigate the abundance and size distribution of rocks in the ejecta and interior. Lunar nighttime "cold spots" are anomalous features around very young impact craters, extending for up to hundreds of crater radii, notable for their low temperatures in the Diviner nighttime data [9]. Although their origins are not fully explained, they are likely the result of in-situ disruption and decompression of regolith during the impact process. The selected cold spot (one of hundreds or even thousands on the lunar surface) was located with good viewing ge- ometry from LRO, and had a diameter of ~10 km surrounding a crater < 1 km in diameter. At Kepler crater, we observed dramatic differences in the amount of cooling related to the

  20. Integrating Satellite, Radar and Surface Observation with Time and Space Matching

    NASA Astrophysics Data System (ADS)

    Ho, Y.; Weber, J.

    2015-12-01

    The Integrated Data Viewer (IDV) from Unidata is a Java™-based software framework for analyzing and visualizing geoscience data. It brings together the ability to display and work with satellite imagery, gridded data, surface observations, balloon soundings, NWS WSR-88D Level II and Level III RADAR data, and NOAA National Profiler Network data, all within a unified interface. Applying time and space matching on the satellite, radar and surface observation datasets will automatically synchronize the display from different data sources and spatially subset to match the display area in the view window. These features allow the IDV users to effectively integrate these observations and provide 3 dimensional views of the weather system to better understand the underlying dynamics and physics of weather phenomena.

  1. GONG Observations of Solar Surface Flows

    PubMed

    Hathaway; Gilman; Harvey; Hill; Howard; Jones; Kasher; Leibacher; Pintar; Simon

    1996-05-31

    Doppler velocity observations obtained by the Global Oscillation Network Group (GONG) instruments directly measure the nearly steady flows in the solar photosphere. The sun's differential rotation is accurately determined from single observations. The rotation profile with respect to latitude agrees well with previous measures, but it also shows a slight north-south asymmetry. Rotation profiles averaged over 27-day rotations of the sun reveal the torsional oscillation signal-weak, jetlike features, with amplitudes of 5 meters per second, that are associated with the sunspot latitude activity belts. A meridional circulation with a poleward flow of about 20 meters per second is also evident. Several characteristics of the surface flows suggest the presence of large convection cells. PMID:8662460

  2. Fundamental statistical relationships between monthly and daily meteorological variables: Temporal downscaling of weather based on a global observational dataset

    NASA Astrophysics Data System (ADS)

    Sommer, Philipp; Kaplan, Jed

    2016-04-01

    Accurate modelling of large-scale vegetation dynamics, hydrology, and other environmental processes requires meteorological forcing on daily timescales. While meteorological data with high temporal resolution is becoming increasingly available, simulations for the future or distant past are limited by lack of data and poor performance of climate models, e.g., in simulating daily precipitation. To overcome these limitations, we may temporally downscale monthly summary data to a daily time step using a weather generator. Parameterization of such statistical models has traditionally been based on a limited number of observations. Recent developments in the archiving, distribution, and analysis of "big data" datasets provide new opportunities for the parameterization of a temporal downscaling model that is applicable over a wide range of climates. Here we parameterize a WGEN-type weather generator using more than 50 million individual daily meteorological observations, from over 10'000 stations covering all continents, based on the Global Historical Climatology Network (GHCN) and Synoptic Cloud Reports (EECRA) databases. Using the resulting "universal" parameterization and driven by monthly summaries, we downscale mean temperature (minimum and maximum), cloud cover, and total precipitation, to daily estimates. We apply a hybrid gamma-generalized Pareto distribution to calculate daily precipitation amounts, which overcomes much of the inability of earlier weather generators to simulate high amounts of daily precipitation. Our globally parameterized weather generator has numerous applications, including vegetation and crop modelling for paleoenvironmental studies.

  3. Weathering and vegetation controls on nickel isotope fractionation in surface ultramafic environments (Albania)

    NASA Astrophysics Data System (ADS)

    Estrade, Nicolas; Cloquet, Christophe; Echevarria, Guillaume; Sterckeman, Thibault; Deng, Tenghaobo; Tang, YeTao; Morel, Jean-Louis

    2015-08-01

    to be isotopically heavier than the soil (Δ60Niwhole plant-soil up to 0.40‰). Fractions of Ni extracted by DTPA (diethylenetriaminepentaacetic acid) presented isotopically heavy compositions compared to the soil (Δ60NiDTPA-soil up to 0.89‰), supporting the hypothesis that the dissolved Ni fraction controlled by weathering has a heavy isotope signature. The non-hyperaccumulators (n = 2) were inclined to take up and translocate light Ni isotopes with a large degree of fractionation (Δ60Nileaves-roots up to - 0.60 ‰). For Ni-hyperaccumulators (n = 7), significant isotopic fractionation was observed in the plants in their early growth stages, while no fractionation occurred during later growth stages, when plants are fully loaded with Ni. This suggests that (i) the high-efficiency translocation process involved in hyperaccumulators does not fractionate Ni isotopes, and (ii) the root uptake process mainly controls the isotopic composition of the plant. In ultramafic contexts, vegetation composed of hyperaccumulators can significantly influence isotopic compositions through its remobilization in the upper soil horizon, thereby influencing the isotopic balance of Ni exported to rivers.

  4. Weather types across the Caribbean basin and their relationship with rainfall and sea surface temperature

    NASA Astrophysics Data System (ADS)

    Moron, Vincent; Gouirand, Isabelle; Taylor, Michael

    2015-10-01

    Eight weather types (WTs) are computed over 98.75°W-56.25°W, 8.75°N-31.25°N using cluster analysis of daily low-level (925 hPa) winds and outgoing longwave radiation, without removing the mean annual cycle, by a k-means algorithm from 1979 to 2013. The WTs can be firstly interpreted as snapshots of the annual cycle with a clear distinction between 5 "wintertime" and 3 "summertime" WTs, which account together for 70 % of the total mean annual rainfall across the studied domain. The wintertime WTs occur mostly from late November to late April and are characterized by varying intensity and location of the North Atlantic subtropical high (NASH) and transient synoptic troughs along the northern edge of the domain. Large-scale subsidence dominates the whole basin but rainfall can occur over sections of the basin, especially on the windward shores of the troughs associated with the synoptic waves. The transition between wintertime and summertime WTs is rather abrupt, especially in May. One summertime WT (WT 4) is prevalent in summer, and almost exclusive around late July. It is characterized by strong NASH, fast Caribbean low level jet and rainfall mostly concentrated over the Caribbean Islands, the Florida Peninsula, the whole Central America and the tropical Eastern Pacific. The two remaining summertime WTs display widespread rainfall respectively from Central America to Bermuda (WT 5) and over the Eastern Caribbean (WT 6). Both WTs combine reduced regional scale subsidence and weaker Caribbean low-level jet relatively to WT 4. The relationships between WT frequency and El Niño Southern Oscillation (ENSO) events are broadly linear. Warm central and eastern ENSO events are associated with more WT 4 (less WT 5-6) during boreal summer and autumn (0) while this relationship is reversed during boreal summer (+1) for central events only. In boreal winter, the largest anomalies are observed for two WTs consistent with negative (WT 2) and positive (WT 8) phases of the

  5. Weather types across the Caribbean basin and their relationship with rainfall and sea surface temperature

    NASA Astrophysics Data System (ADS)

    Moron, Vincent; Gouirand, Isabelle; Taylor, Michael

    2016-07-01

    Eight weather types (WTs) are computed over 98.75°W-56.25°W, 8.75°N-31.25°N using cluster analysis of daily low-level (925 hPa) winds and outgoing longwave radiation, without removing the mean annual cycle, by a k-means algorithm from 1979 to 2013. The WTs can be firstly interpreted as snapshots of the annual cycle with a clear distinction between 5 "wintertime" and 3 "summertime" WTs, which account together for 70 % of the total mean annual rainfall across the studied domain. The wintertime WTs occur mostly from late November to late April and are characterized by varying intensity and location of the North Atlantic subtropical high (NASH) and transient synoptic troughs along the northern edge of the domain. Large-scale subsidence dominates the whole basin but rainfall can occur over sections of the basin, especially on the windward shores of the troughs associated with the synoptic waves. The transition between wintertime and summertime WTs is rather abrupt, especially in May. One summertime WT (WT 4) is prevalent in summer, and almost exclusive around late July. It is characterized by strong NASH, fast Caribbean low level jet and rainfall mostly concentrated over the Caribbean Islands, the Florida Peninsula, the whole Central America and the tropical Eastern Pacific. The two remaining summertime WTs display widespread rainfall respectively from Central America to Bermuda (WT 5) and over the Eastern Caribbean (WT 6). Both WTs combine reduced regional scale subsidence and weaker Caribbean low-level jet relatively to WT 4. The relationships between WT frequency and El Niño Southern Oscillation (ENSO) events are broadly linear. Warm central and eastern ENSO events are associated with more WT 4 (less WT 5-6) during boreal summer and autumn (0) while this relationship is reversed during boreal summer (+1) for central events only. In boreal winter, the largest anomalies are observed for two WTs consistent with negative (WT 2) and positive (WT 8) phases of the

  6. Comparison of surface water chemistry and weathering effects of two lake basins in the Changtang Nature Reserve, China.

    PubMed

    Wang, Rui; Liu, Zhaofei; Jiang, Liguang; Yao, Zhijun; Wang, Junbo; Ju, Jianting

    2016-03-01

    The geochemistry of natural waters in the Changtang Nature Reserve, northern Tibet, can help us understand the geology of catchments, and provide additional insight in surface processes that influence water chemistry such as rock weathering on the Qinghai-Tibet Plateau. However, severe natural conditions are responsible for a lack of scientific data for this area. This study represents the first investigation of the chemical composition of surface waters and weathering effects in two lake basins in the reserve (Lake Dogaicoring Qiangco and Lake Longwei Co). The results indicate that total dissolved solids (TDS) in the two lakes are significantly higher than in other gauged lakes on the Qinghai-Tibet Plateau, reaching 20-40g/L, and that TDS of the tectonic lake (Lake Dogaicoring Qiangco) is significantly higher than that of the barrier lake (Lake Longwei Co). Na(+) and Cl(-) are the dominant ions in the lake waters as well as in the glacier-fed lake inflows, with chemical compositions mainly affected by halite weathering. In contrast, ion contents of inflowing rivers fed by nearby runoff are lower and concentrations of dominant ions are not significant. Evaporite, silicate, and carbonate weathering has relatively equal effects on these rivers. Due to their limited scope, small streams near the lakes are less affected by carbonate than by silicate weathering. PMID:26969064

  7. Delving Deeper: How Saprolite And Chemical Weathering Influence The Expression Of Climate On Surface Shaping Processes

    NASA Astrophysics Data System (ADS)

    Dixon, J. L.; Heimsath, A. M.; Amundson, R.

    2008-12-01

    Climate, erosion, chemical weathering, and hillslope form are intricately linked by a set of feedbacks controlling the evolution of soil mantled landscapes. Our current understanding of their functional relationships is hampered by the lack of field data quantifying erosion and weathering variability at a hillslope scale. Here, we examine how climate influences hillslope form and function along a 64 km climate transect up the western front of the southern Sierra Nevada, California. We use cosmogenic 10Be and chemical mass balances to quantify rates of soil production, physical erosion, and chemical weathering. We couple denudation rates with high resolution laser altimetry data and measurements of soil thickness to examine the morphometric expression of climate and dominant soil transport processes. Importantly, we include measurements of deep chemical weathering in saprolites beneath soil, to better understand the role of saprolite in both expressing climate influence and influencing erosion-weathering feedbacks. We test several soil transport laws, which express predictable functional relationships between soil flux and landscape form, based either on the role that gravity or hillslope gradient or on the extent that soil depth may influence soil production and flux. Rates of local soil production range from 31.2 to 160.0 t km-2y-1 across the climate gradient, reflecting average lowering rates of 36.5 ± 2.8 m My-1. Soil production rates decrease with soil thickness at the low elevation grassland site, in agreement with published data from similar landscapes; however, we find limited applicability of existing transport laws to hillslope form at other sites in the Sierra Nevada. Along the studied climate gradient, chemical weathering rates peak at middle elevations (1200-2000 m), averaging 112.3 ± 9.7 t km-2y-1 compared to high and low elevation sites (46.8 ± 5.2 t km-2y-1). Patterns of weathering rates with elevation are similar to those of predicted silica

  8. Solar Wind Interaction with Lunar Magnetic Fields: ARTEMIS Observations and Correlations with Surface Properties

    NASA Astrophysics Data System (ADS)

    Halekas, J. S.; Blewett, D. T.; Poppe, A. R.; Brain, D. A.

    2014-12-01

    Lunar magnetic fields, though small in scale and comparatively weak, have surprisingly significant effects on the incoming plasma, and a number of observations suggest that their presence may locally alter the space weathering of the surface. Recent observations from Kaguya and Chandrayaan have shown that lunar magnetic anomalies efficiently reflect incoming solar wind protons, providing substantial shielding of portions of the crust, with potential implications for both space weathering and surface sputtering. The two ARTEMIS probes have made a number of low-altitude (tens of kilometers) passes over regions with moderately strong crustal magnetic fields, at local times both near the sub-solar point and at the terminator. Several such passes occurred over a region of the surface containing unusual albedo markings - or "swirls" - that could indicate a local reduction in space weathering. We investigate the ARTEMIS low-altitude passes in detail, focusing on how the observed reflected protons and other local modifications of charged particle distributions and electromagnetic fields relate to the properties of the surface.

  9. Labrador Sea surface temperature control on the summer weather in the Eastern Europe

    NASA Astrophysics Data System (ADS)

    Gnatiuk, Natalia; Vihma, Timo; Bobylev, Leonid

    2016-04-01

    Many studies have addressed the linkages between the Arctic Amplification and mid-latitude weather patterns. Most of them have focused on the effects of changes in sea ice, terrestrial snow or open ocean SST on the air temperature in selected mid-latitude areas. However, when analysing such potential linkages, one should be aware that from the point of view of the atmosphere it is almost the same whether the thermal forcing originates from the sea ice melt, snowmelt, or changes in SST. Most important is to quantify how the atmosphere responds to anomalies in the surface temperature and then affects weather patterns in remote areas. For this purpose, we studied the hemispheric-scale relationships between anomalies in the Northern Hemisphere Earth surface temperature (Ts) and 2-m air temperature (T2m) in mid-latitudes (Central and Eastern Europe). Using regression analyses based on the ERA-Interim reanalysis data, we assessed the said temperature relationships with focus on the lagged monthly and inter-seasonal linkages. Technically we divided the Northern Hemisphere in equal areas with a size of 15x10 degrees and calculated correlation coefficients for the monthly mean temperatures between all defined regions from one side and the Central/East European study regions from another side over the period 1979-2014. Using this approach, we found that the strongest links in the considered kind of relationships take place between spring sea surface temperature in the Labrador Sea and summer air (T2m) temperature in the Eastern Europe. In order to confirm the correlation results obtained, to identify thermal forcing factors and to assess their relative importance, we analysed the multiyear averages and anomalies of various meteorological parameters for 10 coldest and 10 warmest springs and summers in the period 1979-2014: surface pressure, total precipitation, sea-ice and total cloud cover, wind components, surface solar radiation downwards, surface heat fluxes and air

  10. Soil, snow, weather, and sub-surface storage data from a mountain catchment in the rain-snow transition zone

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A comprehensive hydroclimatic data set is presented for the 2011 water year to improve understanding of hydrologic processes in the rain-snow transition zone. Catchment soil depths and surface texture from 57 points are presented along with soil moisture, snow cover, weather data, and associated hy...

  11. Fluorescent beeswax for surface flow velocity observations

    NASA Astrophysics Data System (ADS)

    Grimaldi, S.; Tauro, F.; Petroselli, A.; Mocio, G.; Capocci, I.; Rapiti, E.; Rapiti, R.; Cipollari, G.; Porfiri, M.

    2012-12-01

    Watershed surface processes control downstream runoff phenomena, waste and pollutant diffusion, erosion mechanics, and sediment transport. A quantitative understanding of the flow physics is currently limited by the lack of effective tracing techniques suitable for basin-scale observations. More specifically, field experiments require environmentally resilient, non-invasive, and low cost measurement systems that can potentially operate in remotely-controlled or unmanned conditions. Traditional tracing methodologies are largely not capable to cope with extreme in-situ conditions, including practical logistic challenges as well as inherent flow complexity. Specifically, most of available technologies need physical sampling to estimate the tracer concentration and do not allow for continuous-time measurements. In addition, commonly used tracers, such as isotopes, dyes, and chemicals, are not directly applicable to monitor surface hillslope processes and large-scale microchannel networks due to elaborate detection processes and dispersion issues. In this context, the feasibility of using buoyant fluorescent microspheres as particle tracers in natural water flows is investigated. Specifically, a novel fabrication methodology is designed to manufacture particles from natural beeswax and a highly diluted solution of a nontoxic fluorescent red dye. The fabrication procedure allows for adjusting the size of the particles from tens of microns up to a few millimeters and their density from positively to negatively-buoyant with respect to water. An array of experimental techniques is employed to conduct a thorough characterization of the fluorescence and morphology of the tracers. In addition, ad-hoc experiments are designed to assess the fluorescence response due to Ultra Violet (UV) exposure and thermal processes. Proof-of-concept laboratory analysis are conducted to illustrate the integration of the novel particle tracers in existing tracing methods for surface flow

  12. Simulation studies of the impact of future observing systems on weather prediction

    NASA Technical Reports Server (NTRS)

    Atlas, R.; Kalnay, E.; Baker, W. E.; Susskind, J.; Reuter, D.; Halem, M.

    1985-01-01

    The features and preliminary results from a simulation system being implemented to develop realistic estimates of the impacts future data acquisition systems will have on large-scale numerical weather simulation are described. The new instruments may include advanced passive IR and microwave satellite sensors, as well as active scatterometer and lidar sounders. A main goal of the impact study is to identify those sensor systems which will provide the most benefit. The realism of the study is being enhanced by assimilating as much real-world data as possible and generating global weather maps for comparison with maps generated on the bases on the projected new, higher resolution data. Early results have indicated a preference for higher resolution wind data than for temperature data for making 1-5 day forecasts. The prime instrument candidate for collecting the data is lidar, provided the sensor resolution design goals are met.

  13. 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

    USGS Publications Warehouse

    White, A.F.; Blum, A.E.; Schulz, M.S.; Bullen, T.D.; Harden, J.W.; Peterson, M.L.

    1996-01-01

    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. Maximum volume decreases of >50% occur in the older soils. BET surface areas of the bulk soils increase with age, as do specific surface areas of aluminosilicate mineral fractions such as plagioclase, which increases from 0.4-1.5 m2 g-1 over 600 Ky. Quartz surface areas are lower and change less with time (0.11-0.23 m2 g-1). BET surface areas correspond to increasing external surface roughness (?? = 10-600) and relatively constant internal surface area (??? 1.3 m2 g-1). SEM observations confirm both surface pitting and development of internal porosity. A numerical model describes aluminosilicate dissolution rates as a function of changes in residual mineral abundance, grain size distributions, and mineral surface areas with time. A simple geometric treatment, assuming spherical grains and no surface roughness, predicts average dissolution rates (plagioclase, 10-17.4; K-feldspar, 10-17.8; and hornblende, 10-17.5 mol cm-1 s-1) that are constant with time and comparable to previous estimates of soil weathering. Average rates, based on BET surface area measurements and variable surface roughnesses, are much slower (plagioclase, 10-19.9; K-feldspar, 10-20.5; and hornblende 10-20.1 mol cm-2 s-1). Rates for individual soil horizons decrease by a factor of 101.5 over 3000 Ky indicating that the surface reactivities of minerals decrease as the physical surface areas increase. Rate constants based on BET estimates for the Merced soils are factors of 103-104 slower than reported experimental dissolution rates determined from freshly prepared silicates with low surface

  14. Open Surface Solar Irradiance Observations - A Challenge

    NASA Astrophysics Data System (ADS)

    Menard, Lionel; Nüst, Daniel; Jirka, Simon; Maso, Joan; Ranchin, Thierry; Wald, Lucien

    2015-04-01

    The newly started project ConnectinGEO funded by the European Commission aims at improving the understanding on which environmental observations are currently available in Europe and subsequently providing an informational basis to close gaps in diverse observation networks. The project complements supporting actions and networking activities with practical challenges to test and improve the procedures and methods for identifying observation data gaps, and to ensure viability in real world scenarios. We present a challenge on future concepts for building a data sharing portal for the solar energy industry as well as the state of the art in the domain. Decision makers and project developers of solar power plants have identified the Surface Solar Irradiance (SSI) and its components as an important factor for their business development. SSI observations are crucial in the process of selecting suitable locations for building new plants. Since in-situ pyranometric stations form a sparse network, the search for locations starts with global satellite data and is followed by the deployment of in-situ sensors in selected areas for at least one year. To form a convincing picture, answers must be sought in the conjunction of these EO systems, and although companies collecting SSI observations are willing to share this information, the means to exchange in-situ measurements across companies and between stakeholders in the market are still missing. We present a solution for interoperable exchange of SSI data comprising in-situ time-series observations as well as sensor descriptions based on practical experiences from other domains. More concretely, we will apply concepts and implementations of the Sensor Web Enablement (SWE) framework of the Open Geospatial Consortium (OGC). The work is based on an existing spatial data infrastructure (SDI), which currently comprises metadata, maps and coverage data, but no in-situ observations yet. This catalogue is already registered in the

  15. Near-Real Time Satellite-Retrieved Cloud and Surface Properties for Weather and Aviation Safety Applications

    NASA Technical Reports Server (NTRS)

    Minnis, Patrick; Smith, William L., Jr.; Bedka, Kristopher M.; Nguyen, Louis; Palikonda, Rabindra; Hong, Gang; Trepte, Qing Z.; Chee, Thad; Scarino, Benjamin; Spangenberg, Douglas A.; Sun-Mack, Szedung; Fleeger, Cecilia; Ayers, J. Kirk; Chang, Fu-Lung; Heck, Patrick M.

    2014-01-01

    Cloud properties determined from satellite imager radiances provide a valuable source of information for nowcasting and weather forecasting. In recent years, it has been shown that assimilation of cloud top temperature, optical depth, and total water path can increase the accuracies of weather analyses and forecasts. Aircraft icing conditions can be accurately diagnosed in near-­-real time (NRT) retrievals of cloud effective particle size, phase, and water path, providing valuable data for pilots. NRT retrievals of surface skin temperature can also be assimilated in numerical weather prediction models to provide more accurate representations of solar heating and longwave cooling at the surface, where convective initiation. These and other applications are being exploited more frequently as the value of NRT cloud data become recognized. At NASA Langley, cloud properties and surface skin temperature are being retrieved in near-­-real time globally from both geostationary (GEO) and low-­-earth orbiting (LEO) satellite imagers for weather model assimilation and nowcasting for hazards such as aircraft icing. Cloud data from GEO satellites over North America are disseminated through NCEP, while those data and global LEO and GEO retrievals are disseminated from a Langley website. This paper presents an overview of the various available datasets, provides examples of their application, and discusses the use of the various datasets downstream. Future challenges and areas of improvement are also presented.

  16. Near-Real Time Satellite-Retrieved Cloud and Surface Properties for Weather and Aviation Safety Applications

    NASA Astrophysics Data System (ADS)

    Minnis, P.; Smith, W., Jr.; Bedka, K. M.; Nguyen, L.; Palikonda, R.; Hong, G.; Trepte, Q.; Chee, T.; Scarino, B. R.; Spangenberg, D.; Sun-Mack, S.; Fleeger, C.; Ayers, J. K.; Chang, F. L.; Heck, P. W.

    2014-12-01

    Cloud properties determined from satellite imager radiances provide a valuable source of information for nowcasting and weather forecasting. In recent years, it has been shown that assimilation of cloud top temperature, optical depth, and total water path can increase the accuracies of weather analyses and forecasts. Aircraft icing conditions can be accurately diagnosed in near-real time (NRT) retrievals of cloud effective particle size, phase, and water path, providing valuable data for pilots. NRT retrievals of surface skin temperature can also be assimilated in numerical weather prediction models to provide more accurate representations of solar heating and longwave cooling at the surface, where convective initiation. These and other applications are being exploited more frequently as the value of NRT cloud data become recognized. At NASA Langley, cloud properties and surface skin temperature are being retrieved in near-real time globally from both geostationary (GEO) and low-earth orbiting (LEO) satellite imagers for weather model assimilation and nowcasting for hazards such as aircraft icing. Cloud data from GEO satellites over North America are disseminated through NCEP, while those data and global LEO and GEO retrievals are disseminated from a Langley website. This paper presents an overview of the various available datasets, provides examples of their application, and discusses the use of the various datasets downstream. Future challenges and areas of improvement are also presented.

  17. Evapotranspiration from nonuniform surfaces - A first approach for short-term numerical weather prediction

    NASA Technical Reports Server (NTRS)

    Wetzel, Peter J.; Chang, Jy-Tai

    1988-01-01

    Observations of surface heterogeneity of soil moisture from scales of meters to hundreds of kilometers are discussed, and a relationship between grid element size and soil moisture variability is presented. An evapotranspiration model is presented which accounts for the variability of soil moisture, standing surface water, and vegetation internal and stomatal resistance to moisture flow from the soil. The mean values and standard deviations of these parameters are required as input to the model. Tests of this model against field observations are reported, and extensive sensitivity tests are presented which explore the importance of including subgrid-scale variability in an evapotranspiration model.

  18. Space Weathering of Small Bodies

    NASA Astrophysics Data System (ADS)

    McFadden, L. A.

    2002-12-01

    Space weathering is defined as any process that wears away and alters surfaces, here confined to small bodies in the Solar System. Mechanisms which possibly alter asteroid and comet surfaces include solar wind bombardment, UV radiation, cosmic ray bombardment, micrometeorite bombardment. These processes are likely to contribute to surface processes differently. For example, solar wind bombardment would be more important on a body closer to the Sun compared to a comet where cosmic ray bombardment might be a more significant weathering mechanism. How can we measure the effects of space weathering? A big problem is that we don't know the nature of the surface before it was weathered. We are in a new era in the study of surface processes on small bodies brought about by the availability of spatially resolved, color and spectral measurements of asteroids from Galileo and NEAR. What processes are active on which bodies? What physics controls surface processes in different regions of the solar system? How do processes differ on different bodies of different physical and chemical properties? What combinations of observable parameters best address the nature of surface processes? Are there alternative explanations for the observed parameters that have been attributed to space weathering? Should we retain the term, space weathering? How can our understanding of space weathering on the Moon help us understand it on asteroids and comets? Finally, we have to leave behind some presuppositions, one being that there is evidence of space weathering based on the fact that the optical properties of S-type asteroids differs from those of ordinary chondrites.

  19. Spectral observations of 19 weathered and 23 fresh NEAs and their correlations with orbital parameters

    NASA Astrophysics Data System (ADS)

    Fevig, Ronald A.; Fink, Uwe

    2007-05-01

    Results of our visible to near-infrared spectrophotometric observations of 41 near-Earth asteroids (NEAs) are reported. These moderate-resolution spectra, along with 14 previously published spectra from our earlier survey [Hicks, M.D., Fink, U., Grundy, W.M., 1998. Icarus 133, 69-78] show a preponderance of spectra consistent with ordinary chondrites (23 NEAs with this type of spectrum, along with 19 S-types and 13 in other taxonomic groups). There exists statistically significant evidence for orbit-dependent trends in our data. While S-type NEAs from our survey reside primarily in (1) Amor orbits or (2) Aten or Apollo orbits which do not cross the asteroid main-belt, the majority of objects with spectra consistent with ordinary chondrites in our survey are in highly eccentric Apollo orbits which enter the asteroid main-belt. This trend toward fresh, relatively unweathered NEAs with ordinary chondrite type spectra in highly eccentric Apollo orbits is attributed to one or a combination of three possible causes: (1) the chaotic nature of NEA orbits can easily result in high eccentricity orbits/large aphelion distances so that they can enter the collisionally enhanced environment in the main-belt, exposing fresh surfaces, (2) they have recently been injected into such orbits after a collision in the main-belt, or (3) such objects cross the orbits of several terrestrial planets, causing tidal disruption events that expose fresh surfaces.

  20. Quantifying Surface Energy Flux Estimation Uncertainty Using Land Surface Temperature Observations

    NASA Astrophysics Data System (ADS)

    French, A. N.; Hunsaker, D.; Thorp, K.; Bronson, K. F.

    2015-12-01

    Remote sensing with thermal infrared is widely recognized as good way to estimate surface heat fluxes, map crop water use, and detect water-stressed vegetation. When combined with net radiation and soil heat flux data, observations of sensible heat fluxes derived from surface temperatures (LST) are indicative of instantaneous evapotranspiration (ET). There are, however, substantial reasons LST data may not provide the best way to estimate of ET. For example, it is well known that observations and models of LST, air temperature, or estimates of transport resistances may be so inaccurate that physically based model nevertheless yield non-meaningful results. Furthermore, using visible and near infrared remote sensing observations collected at the same time as LST often yield physically plausible results because they are constrained by less dynamic surface conditions such as green fractional cover. Although sensitivity studies exist that help identify likely sources of error and uncertainty, ET studies typically do not provide a way to assess the relative importance of modeling ET with and without LST inputs. To better quantify model benefits and degradations due to LST observational inaccuracies, a Bayesian uncertainty study was undertaken using data collected in remote sensing experiments at Maricopa, Arizona. Visible, near infrared and thermal infrared data were obtained from an airborne platform. The prior probability distribution of ET estimates were modeled using fractional cover, local weather data and a Penman-Monteith mode, while the likelihood of LST data was modeled from a two-source energy balance model. Thus the posterior probabilities of ET represented the value added by using LST data. Results from an ET study over cotton grown in 2014 and 2015 showed significantly reduced ET confidence intervals when LST data were incorporated.

  1. Estimation of sea-surface winds using backscatter cross-section measurements from airborne research weather radar

    SciTech Connect

    Hildebrand, P.H. . Remote Sensing Facility)

    1994-01-01

    A technique is presented for estimation of sea-surface winds using backscatter cross-section measurements from an airborne research weather radar. The technique is based on an empirical relation developed for use with satellite-borne microwave scatterometers which derives sea-surface winds from radar backscatter cross-section measurements. Unlike a scatterometer, the airborne research weather radar is a Doppler radar designed to measure atmospheric storm structure and kinematics. Designed to scan the atmosphere, the radar also scans the ocean surface over a wide range of azimuths, with the incidence angle and polarization angle changing continuously during each scan. The new sea-surface wind estimation technique accounts for these variations in incidence angle and polarization and derives the atmospheric surface winds. The technique works well over the range of wind conditions over which the wind speed-backscatter cross-section relation holds, about 2--20 m/s. The problems likely to be encountered with this new technique are evaluated and it is concluded that most problems are those which are endemic to any microwave scatterometer wind estimation technique. The new technique will enable using the research weather radar to provide measurements which would otherwise require use of a dedicated scatterometer.

  2. Comparative Analysis of Thunderstorm Activity in the West Caucasus According to the Instrumental Measurements and Weather Stations Observations

    NASA Astrophysics Data System (ADS)

    Knyazeva, Zalina; Gergokova, Zainaf; Gyatov, Ruslan; Boldyreff, Anton

    2014-05-01

    The number of thunderstorms days is one of the main characteristics of thunderstorms. In most cases, the number of days with different meteorological phenomena are the climate characteristic of the area. This characteristic is a common climate indicator. The comparative analysis of thunderstorms days quantity, received with lightning detector LS 8000 by Vaisala and weather stations of Krasnodar District (Russia), is presented. For this purpose the Krasnodar region was divided into 19 sites. The thunderstorm days amount and their comparison were conducted for each site according to the data of weather stations and LS 8000 lightning detectors. Totally 29 weather stations are located in this area. The number of thunderstorm days per year for the period of 2009-2012 was determined according to data, received from stations. It was received that average annual number of thunderstorm days for this area was from 33 to 39 days. The majority of thunderstorm days per year (up to 77) was registered in the south of Krasnodar region and on the Black Sea coast. The lowest thunderstorm activity (about 20 days) was observed in the North of the region. To compare visual and voice data for calculating thunderstorm days quantity of the Krasnodar region, the day was considered thundery if at least one weather station registered a storm. These instrumental observations of thunderstorms allow to obtain the basic characteristics and features of the distribution of thunderstorm activity over a large territory for a relatively short period of time. However, some characteristics such as thunderstorms intensity, damages from lightning flashes and others could be obtained only with instrumental observations. The territory of gathering thunderstorm discharges data by system LS8000 is limited by perimeter of 2250 km and square of 400 000 km2. According to the instrumental observations, the majority of storm activity also takes place on the Black Sea coast, near the cities of Sochi and Tuapse

  3. Impact of atmospheric CO2 rise on chemical weathering of the continental surfaces

    NASA Astrophysics Data System (ADS)

    Godderis, Y.; Roelandt, C.; Beaulieu, E.; Kaplan, J. O.; Schott, J.

    2009-04-01

    Continental weathering consumes atmospheric CO2. Recent analysis of field data has shown that this flux is rapidly reacting to ongoing climate (ref 1) and land use changes (ref 2), displaying an increase of up to 40 % over a few decades. Weathering processes are thus a potentially important component of the present day global carbon cycle. We developed numerical model describing continental weathering reactions based on laboratory kinetic laws and coupled to numerical model of the productivity of the biosphere (B-WITCH)(ref 3,4). This model is able to simulate the chemical composition of streams for both small and large continental watersheds. In this model, we emphasized the role of land plants in controlling belowground hydrological fluxes and decreasing the pH of percolating water through root respiration, both of which heavily impact weathering rates. Both climate change and increasing atmospheric CO2 concentrations affect the productivity and biogeography of the terrestrial biosphere through direct climate effects and CO2 fertilization. With our weathering model coupled to a dynamic global vegetation model, we have the capability to explore the impact of CO2 and climate change on rock weathering. With regards to CO2 fertilization, we calculate that the overall weathering rate may potentially rise by 20 % when CO2 increases up to 8 times the present day pressure for a large tropical watershed (Orinoco). This change is driven by a decrease in evapotranspiration when CO2 rises, and thus by an increase in the weathering profile drainage. We extend our sensitivity tests to the fertilization effect to 20 sites all over the world under various climatic, biospheric and lithologic conditions, and the results will be discussed. ref 1: Gislason et al., EPSL, 277, 213-222, 2008 ref 2: Raymond et al.,Nature, 451, 449-452, 2008 ref 3: Godd

  4. Cloud Observation and Modeling Test Bed for Air Force Weather Applications: Overview and First Results

    NASA Astrophysics Data System (ADS)

    Nobis, T. E.

    2012-12-01

    Air Force Weather (AFW) has documented requirements for real-time cloud analysis and short range cloud forecasts to support DoD missions around the world. To meet these needs, AFW utilizes the Cloud Depiction and Forecast System (CDFS) II system to develop a hourly cloud analysis and short range forecast. The system creates cloud masks from 16 different satellite sources and optimally merges them to create the analysis. This analysis then forms the initialization field for a short range 'advective' based cloud forecast. Northrop Grumman Corp. has recently delivered a CDFS II based Cloud Model Test Bed. This system offers the ability to test several aspects of the CDFS II system including: the effect of adding and subtracting sources of cloud imagery, the effect of changing source and skill of required external data sources, and the impact of changing the cloud information merge process among the various sources. In addition, the test bed offers a capability to generate a robust cloud modeling baseline against which to measure progress of a next generation Numerical Weather Prediction (NWP) based advanced data assimilation system. Finally, the test bed allows the development and testing of new cloud modeling validation techniques (and sources) to provide greater confidence in results generated from the test bed. This presentation will provide a basic overview of the CDFS II system and of the newly developed Test Bed and will include results from the first series of experiments conducted using the Test Bed.

  5. BET surface area distributions in polar stream sediments: Implications for silicate weathering in a cold-arid environment

    USGS Publications Warehouse

    Marra, Kristen R.; Elwood Madden, Megan E; Soreghan, Gerilyn S.; Hall, Brenda L

    2014-01-01

    BET surface area values are critical for quantifying the amount of potentially reactive sediments available for chemical weathering and ultimately, prediction of silicate weathering fluxes. BET surface area values of fine-grained (<62.5 μm) sediment from the hyporheic zone of polar glacial streams in the McMurdo Dry Valleys, Antarctica (Wright and Taylor Valleys) exhibit a wide range (2.5–70.6 m2/g) of surface area values. Samples from one (Delta Stream, Taylor Valley) of the four sampled stream transects exhibit high values (up to 70.6 m2/g), which greatly exceed surface area values from three temperate proglacial streams (0.3–12.1 m2/g). Only Clark stream in Wright Valley exhibits a robust trend with distance, wherein surface area systematically decreases (and particle size increases) in the mud fraction downstream, interpreted to reflect rapid dissolution processes in the weathering environment. The remaining transects exhibit a range in variability in surface area distributions along the length of the channel, likely related to variations in eolian input to exposed channel beds, adjacent snow drifts, and to glacier surfaces, where dust is trapped and subsequently liberated during summer melting. Additionally, variations in stream discharge rate, which mobilizes sediment in pulses and influences water:rock ratios, the origin and nature of the underlying drift material, and the contribution of organic acids may play significant roles in the production and mobilization of high-surface area sediment. This study highlights the presence of sediments with high surface area in cold-based glacier systems, which influences models of chemical denudation rates and the impact of glacial systems on the global carbon cycle.

  6. All-Weather Sounding of Moisture and Temperature From Microwave Sensors Using a Coupled Surface/Atmosphere Inversion Algorithm

    NASA Astrophysics Data System (ADS)

    Boukabara, S. A.; Garrett, K.

    2014-12-01

    A one-dimensional variational retrieval system has been developed, capable of producing temperature and water vapor profiles in clear, cloudy and precipitating conditions. The algorithm, known as the Microwave Integrated Retrieval System (MiRS), is currently running operationally at the National Oceanic and Atmospheric Administration (NOAA) National Environmental Satellite Data and Information Service (NESDIS), and is applied to a variety of data from the AMSU-A/MHS sensors on board the NOAA-18, NOAA-19, and MetOp-A/B polar satellite platforms, as well as SSMI/S on board both DMSP F-16 and F18, and from the NPP ATMS sensor. MiRS inverts microwave brightness temperatures into atmospheric temperature and water vapor profiles, along with hydrometeors and surface parameters, simultaneously. This atmosphere/surface coupled inversion allows for more accurate retrievals in the lower tropospheric layers by accounting for the surface emissivity impact on the measurements. It also allows the inversion of the soundings in all-weather conditions thanks to the incorporation of the hydrometeors parameters in the inverted state vector as well as to the inclusion of the emissivity in the same state vector, which is accounted for dynamically for the highly variable surface conditions found under precipitating atmospheres. The inversion is constrained in precipitating conditions by the inclusion of covariances for hydrometeors, to take advantage of the natural correlations that exist between temperature and water vapor with liquid and ice cloud along with rain water. In this study, we present a full assessment of temperature and water vapor retrieval performances in all-weather conditions and over all surface types (ocean, sea-ice, land, and snow) using matchups with radiosonde as well as Numerical Weather Prediction and other satellite retrieval algorithms as references. An emphasis is placed on retrievals in cloudy and precipitating atmospheres, including extreme weather events

  7. Road Weather and Connected Vehicles

    NASA Astrophysics Data System (ADS)

    Pisano, P.; Boyce, B. C.

    2015-12-01

    On average, there are over 5.8 M vehicle crashes each year of which 23% are weather-related. Weather-related crashes are defined as those crashes that occur in adverse weather or on slick pavement. The vast majority of weather-related crashes happen on wet pavement (74%) and during rainfall (46%). Connected vehicle technologies hold the promise to transform road-weather management by providing improved road weather data in real time with greater temporal and geographic accuracy. This will dramatically expand the amount of data that can be used to assess, forecast, and address the impacts that weather has on roads, vehicles, and travelers. The use of vehicle-based measurements of the road and surrounding atmosphere with other, more traditional weather data sources, and create road and atmospheric hazard products for a variety of users. The broad availability of road weather data from mobile sources will vastly improve the ability to detect and forecast weather and road conditions, and will provide the capability to manage road-weather response on specific roadway links. The RWMP is currently demonstrating how weather, road conditions, and related vehicle data can be used for decision making through an innovative Integrated Mobile Observations project. FHWA is partnering with 3 DOTs (MN, MI, & NV) to pilot these applications. One is a mobile alerts application called the Motorists Advisories and Warnings (MAW) and a maintenance decision support application. These applications blend traditional weather information (e.g., radar, surface stations) with mobile vehicle data (e.g., temperature, brake status, wiper status) to determine current weather conditions. These weather conditions, and other road-travel-relevant information, are provided to users via web and phone applications. The MAW provides nowcasts and short-term forecasts out to 24 hours while the EMDSS application can provide forecasts up to 72 hours in advance. The three DOTs have placed readers and external

  8. Comparative study of pulsed laser cleaning applied to weathered marble surfaces

    NASA Astrophysics Data System (ADS)

    Ortiz, P.; Antúnez, V.; Ortiz, R.; Martín, J. M.; Gómez, M. A.; Hortal, A. R.; Martínez-Haya, B.

    2013-10-01

    The removal of unwanted matter from surface stones is a demanding task in the conservation of cultural heritage. This paper investigates the effectiveness of near-infrared (IR) and ultraviolet (UV) laser pulses for the cleaning of surface deposits, iron oxide stains and different types of graffiti (black, red and green sprays and markers, and black cutting-edge ink) on dolomitic white marble. The performance of the laser techniques is compared to common cleaning methods on the same samples, namely pressurized water and chemical treatments. The degree of cleaning achieved with each technique is assessed by means of colorimetric measurements and X-ray microfluorescence. Eventual morphological changes induced on the marble substrate are monitored with optical and electronic microscopy. It is found that UV pulsed laser ablation at 266 nm manages to clean all the stains except the cutting-edge ink, although some degree of surface erosion is produced. The IR laser pulses at 1064 nm can remove surface deposits and black spray acceptably, but a yellowing is observed on the stone surface after treatment. An economic evaluation shows that pulsed laser cleaning techniques are advantageous for the rapid cleaning of small or inaccessible surface areas, although their extensive application becomes expensive due to the long operating times required.

  9. Problems at the Leading Edge of Space Weathering as Revealed by TEM Combined with Surface Science Techniques

    NASA Technical Reports Server (NTRS)

    Christoffersen, R.; Dukes, C. A.; Keller, L. P.; Rahman, Z.; Baragiola, R. A.

    2015-01-01

    Both transmission electron micros-copy (TEM) and surface analysis techniques such as X-ray photoelectron spectroscopy (XPS) were instrumen-tal in making the first characterizations of material generated by space weathering in lunar samples [1,2]. Without them, the nature of nanophase metallic Fe (npFe0) correlated with the surface of lunar regolith grains would have taken much longer to become rec-ognized and understood. Our groups at JSC and UVa have been using both techniques in a cross-correlated way to investigate how the solar wind contributes to space weathering [e.g., 3]. These efforts have identified a number of ongoing problems and knowledge gaps. Key insights made by UVa group leader Raul Barag-iola during this work are gratefully remembered.

  10. Space Weather Monitoring for ISS Space Environments Engineering and Crew Auroral Observations

    NASA Astrophysics Data System (ADS)

    Minow, J. I.; Pettit, D. R.; Hartman, W. A.

    2012-12-01

    The International Space Station (ISS) space environments community utilizes near real time space weather data in support of a variety of ISS engineering and operations activities. The team has operated the Floating Potential Measurement Unit (FPMU) suite of plasma instruments (two Langmuir probes, a floating potential probe, and a plasma impedance probe) on ISS from 2006 to the present time to obtain in-situ measurements of plasma density and temperature along the ISS orbit and variations in ISS frame potential due to the combined effects of electrostatic current collection processes from the plasma environment and inductive (vxB) effects due to the motion of the vehicle across the Earth's magnetic field. An ongoing effort to use FPMU for measuring the ionospheric response to geomagnetic storms at ISS altitudes and document ISS frame charging as the vehicle passes through regions of precipitating auroral electrons is challenged by restrictions on the available FPMU operation time. The instruments can only be operated during campaign periods limited to about a third of a year in accumulated operation time and FPMU data is down linked through the ISS Ku band telemetry system, a shared resource. As a result, FPMU campaign periods of a few days to weeks have typically been scheduled for periods of a week or two in advance. Capturing geomagnetic storm data under these conditions depended on the fortuitous event of a storm starting during a previously planned FPMU campaign period, an unlikely event at a time when Solar Cycle 24 was ending and a protracted solar minimum gave little in the way of geoeffective solar disturbances. However, with the start of Solar Cycle 24 the number of solar disturbances and associated geomagnetic storms started to increase and we modified our strategy to improve the chances of capturing geomagnetic storm data. We now monitor near real time space weather data from NASA, NOAA, and ESA sources to determine solar wind disturbance arrival times

  11. Identification of weathered structures and aquifers from resistivity observations in the Strengbach catchment (Vosges, France).

    NASA Astrophysics Data System (ADS)

    Gance, Julien; Sailhac, Pascal; Malet, Jean-Philippe; Viville, Daniel; Pierret, Marie-Claire

    2015-04-01

    In low mountain regions, natural water resources used for agriculture or drinking water generally come from natural sources. Management of these water resources is complex for some catchments where most of the water flows is exfiltrating from bedrock aquifers characterized by important spatial heterogeneity and different connectivity levels in space and time. The Strengbach catchment (Vosges, North East France) is a hydro-geochemical observatory monitored for more than 25 years. The numerous geochemical studies have highlighted the existence of different lithological and structural units in the catchment constituted by different weathered granitic aquifers. Their spatial extension has been determined through the measurement of the soil electrical resistivity using 20 Electrical Resistivity Tomography (ERT) profiles. The profiles have been inverted separately with the BERT software in 2D and compared to 2.5 D inversions, where the inversion accounts for the profile crossings. The comparison between 2D and 2.5D inversion results allows validating the 2-D assumption. The 20 profiles are distributed over the complete catchment and cover more densely the water source area of the Strengbach stream. The shallow resistivities (5-10 m) measured highlight several weathered zones possibly characterized by different porosity. A combined analysis with soil water conductivity measurements in boreholes allows proposing a map of the spatial extension of these units. The resistivity data are also used to assess the depth of the main reservoir at the scale of the catchment. The hypothesis of the existence of a deeper reservoir is brought out by Audio-Magneto Telluric (AMT) and Very Low Frequency (VLF) measurements.

  12. Modeling land-surface processes and land-atmosphere interactions in the community weather and regional climate WRF model (Invited)

    NASA Astrophysics Data System (ADS)

    Chen, F.; Barlage, M. J.

    2013-12-01

    The Weather Research and Forecasting (WRF) model has been widely used with high-resolution configuration in the weather and regional climate communities, and hence demands its land-surface models to treat not only fast-response processes, such as plant evapotranspiration that are important for numerical weather prediction but also slow-evolving processes such as snow hydrology and interactions between surface soil water and deep aquifer. Correctly representing urbanization, which has been traditionally ignored in coarse-resolution modeling, is critical for applying WRF to air quality and public health research. To meet these demands, numerous efforts have been undertaken to improve land-surface models (LSM) in WRF, including the recent implementation of the Noah-MP (Noah Multiple-Physics). Noah-MP uses multiple options for key sub-grid land-atmosphere interaction processes (Niu et al., 2011; Yang et al., 2011), and contains a separate vegetation canopy representing within- and under-canopy radiation and turbulent processes, a multilayer physically-based snow model, and a photosynthesis canopy resistance parameterization with a dynamic vegetation model. This paper will focus on the interactions between fast and slow land processes through: 1) a benchmarking of the Noah-MP performance, in comparison to five widely-used land-surface models, in simulating and diagnosing snow evolution for complex terrain forested regions, and 2) the effects of interactions between shallow and deep aquifers on regional weather and climate. Moreover, we will provide an overview of recent improvements of the integrated WRF-Urban modeling system, especially its hydrological enhancements that takes into account the effects of lawn irrigation, urban oasis, evaporation from pavements, anthropogenic moisture sources, and a green-roof parameterization.

  13. Space Weathering Products Found on the Surfaces of the Itokawa Dust Particles: A Summary of the Initial Analysis

    NASA Technical Reports Server (NTRS)

    Noguchi, T.; Kimura, M.; Hashimoto, T.; Konno, M.; Nakamura, T.; Ogami, T.; Ishida, H.; Sagae, R.; Tsujimoto, S.; Tsuchiyama, A,; Zolensky, M. E.; Tanaka, M.; Fujimura, A.; Abe, M.; Yada, T.; Mukai, T.; Ueno, M.; Okada, T.; Shirai, K.; Ishibashi, Y.; Okazaki, R.

    2012-01-01

    Surfaces of airless bodies exposed to interplanetary space gradually have their structures, optical properties, chemical compositions, and mineralogy changed by solar wind implantation and sputtering, irradiation by galactic and solar cosmic rays, and micrometeorite bombardment. These alteration processes and the resultant optical changes are known as space weathering [1, 2, 3]. Our knowledge of space weathering has depended almost entirely on studies of the surface materials returned from the Moon and regolith breccia meteorites [1, 4, 5, 6] until the surface material of the asteroid Itokawa was returned to the Earth by the Hayabusa spacecraft [7]. Lunar soil studies show that space weathering darkens the albedo of lunar soil and regolith, reddens the slopes of their reflectance spectra, and attenuates the characteristic absorption bands of their reflectance spectra [1, 2, 3]. These changes are caused by vapor deposition of small (<40 nm) metallic Fe nanoparticles within the grain rims of lunar soils and agglutinates [5, 6, 8]. The initial analysis of the Itokawa dust particles revealed that 5 out of 10 particles have nanoparticle-bearing rims, whose structure varies depending on mineral species. Sulfur-bearing Fe-rich nanoparticles (npFe) exist in a thin (5-15 nm) surface layer (zone I) on olivine, low-Ca pyroxene, and plagioclase, suggestive of vapor deposition. Sulfur-free npFe exist deeper inside (<60 nm) ferromagnesian silicates (zone II). Their texture suggests formation by amorphization and in-situ reduction of Fe2+ in ferromagnesian silicates [7]. On the other hand, nanophase metallic iron (npFe0) in the lunar samples is embedded in amorphous silicate [5, 6, 8]. These textural differences indicate that the major formation mechanisms of the npFe0 are different between the Itokawa and the lunar samples. Here we report a summary of the initial analysis of space weathering of the Itokawa dust particles.

  14. Simulations and Tests of Prototype Antenna System for Low Frequency Radio Experiment (LORE) Space Payload for Space Weather Observations

    NASA Astrophysics Data System (ADS)

    Pethe, Kaiwalya; Galande, Shridhar; Jamadar, Sachin; Mahajan, S. P.; Patil, R. A.; Joshi, B. C.; Manoharan, P. K.; Roy, Jayashree; Kate, G.

    2016-03-01

    Low frequency Radio Experiment (LORE) is a proposed space payload for space weather observations from space, operating between few kHz to 30 MHz. This paper presents preliminary design and practical implementation of LORE antenna systems, which consist of three mutually orthogonal mono-poles. Detailed computational electromagnetic simulations, carried out to study the performance of the antenna systems, are presented followed up by laboratory tests of the antennas as well as radiation tests with a long range test range, designed for this purpose. These tests form the first phase of the design and implementation of the full LORE prototype later in the year.

  15. Aquarius Observations of Sea Surface Salinity

    NASA Video Gallery

    This visualization shows changes in global sea surface salinity, as measured by NASA’s Aquarius instrument aboard the Aquarius/SAC-D spacecraft, from December 2011 through December 2012. Red repr...

  16. Environmental Education Tips: Weather Activities.

    ERIC Educational Resources Information Center

    Brainard, Audrey H.

    1989-01-01

    Provides weather activities including questions, on weather, heating the earth's surface, air, tools of the meteorologist, clouds, humidity, wind, and evaporation. Shows an example of a weather chart activity. (RT)

  17. A statistical-dynamical scheme for reconstructing ocean forcing in the Atlantic. Part I: weather regimes as predictors for ocean surface variables

    NASA Astrophysics Data System (ADS)

    Cassou, Christophe; Minvielle, Marie; Terray, Laurent; Périgaud, Claire

    2011-01-01

    The links between the observed variability of the surface ocean variables estimated from reanalysis and the overlying atmosphere decomposed in classes of large-scale atmospheric circulation via clustering are investigated over the Atlantic from 1958 to 2002. Daily 500 hPa geopotential height and 1,000 hPa wind anomaly maps are classified following a weather-typing approach to describe the North Atlantic and tropical Atlantic atmospheric dynamics, respectively. The algorithm yields patterns that correspond in the extratropics to the well-known North Atlantic-Europe weather regimes (NAE-WR) accounting for the barotropic dynamics, and in the tropics to wind classes (T-WC) representing the alteration of the trades. 10-m wind and 2-m temperature (T2) anomaly composites derived from regime/wind class occurrence are indicative of strong relationships between daily large-scale atmospheric circulation and ocean surface over the entire Atlantic basin. High temporal correlation values are obtained basin-wide at low frequency between the observed fields and their reconstruction by multiple linear regressions with the frequencies of occurrence of both NAE-WR and T-WC used as sole predictors. Additional multiple linear regressions also emphasize the importance of accounting for the strength of the daily anomalous atmospheric circulation estimated by the combined distances to all regimes centroids in order to reproduce the daily to interannual variability of the Atlantic ocean. We show that for most of the North Atlantic basin the occurrence of NAE-WR generally sets the sign of the ocean surface anomaly for a given day, and that the inter-regime distances are valuable predictors for the magnitude of that anomaly. Finally, we provide evidence that a large fraction of the low-frequency trends in the Atlantic observed at the surface over the last 50 years can be traced back, except for T2, to changes in occurrence of tropical and extratropical weather classes. All together, our

  18. Seasonal changes in Titan's weather patterns and the evolution and implications of accompanying surface changes

    NASA Astrophysics Data System (ADS)

    Turtle, Elizabeth; McEwen, Alfred

    2012-07-01

    Post-equinox changes in Titan's atmospheric circulation brought clouds and extensive methane rain to low latitudes [1,2]. Observations by Cassini ISS over the ensuing ~1.5 yr revealed surface changes to be short-lived; few rain-darkened areas persisted through 2011. In an unsaturated permeable medium, infiltration rates are >20 mm/week [3], so persistence of surface liquids over several months suggests that either an impermeable layer or the local methane table lies close to the surface. Evaporation rates >1 mm/week are predicted at low latitudes [4] and 20 mm/week has been documented at Titan's poles [5], thus areas where darkening persisted must be saturated ground at the level of a methane table or have had ponded liquid 2.5-50 cm deep. Several smaller areas of surface brightening were also observed, a phenomenon that is less well understood. Cassini VIMS spectra of these regions do not match clouds or other surface units [6]. Interpretations include cleaning by runoff [2] or deposition of a fine-grained volatile solid as the result of evaporative cooling of the surface [6]. In general, brightening has persisted longer than darkening, but these areas are also reverting to their original appearance, possibly due to evaporation/sublimation of the bright material or re-deposition of darker hydrocarbons by aeolian transport or precipitation from the atmosphere. Cassini and Earth-based observers monitor Titan frequently, but few clouds have been observed since Fall 2010, which may indicate that enough methane was removed from the atmosphere and the lapse rate stabilized sufficiently that activity will not resume until the onset of convection at mid-northern latitudes later in northern spring. A similar lapse followed a 2004 outburst of south-polar clouds [7], which also appeared to produce significant rainfall [8]. [1] Turtle et al., GRL 38, L03203, doi:10.1029/2010GL046266, 2011. [2] Turtle et al., Science 331, 10.1126/science.1201063. 2011. [3] Hayes et al., GRL 35

  19. Meteorite Falls Observed in U.S. Weather Radar Data in 2015 and 2016 (To Date)

    NASA Technical Reports Server (NTRS)

    Fries, Marc; Fries, Jeffrey; Hankey, Mike; Matson, Robert

    2016-01-01

    To date, over twenty meteorite falls have been located in the weather radar imagery of the National Oceanic and Atmospheric Administration (NOAA)'s NEXRAD radar network. We present here the most prominent events recorded since the last Meteoritical Society meeting, covering most of 2015 and early 2016. Meteorite Falls: The following events produced evidence of falling meteorites in radar imagery and resulted in meteorites recovered at the fall site. Creston, CA (24 Oct 2015 0531 UTC): This event generated 218 eyewitness reports submitted to the American Meteor Society (AMS) and is recorded as event #2635 for 2015 on the AMS website. Witnesses reported a bright fireball with fragmentation terminating near the city of Creston, CA, north of Los Angeles. Sonic booms and electrophonic noise were reported in the vicinity of the event. Weather radar imagery records signatures consistent with falling meteorites in data from the KMUX, KVTX, KHNX and KVBX. The Meteoritical Society records the Creston fall as an L6 meteorite with a total recovered mass of 688g. Osceola, FL (24 Jan 2016 1527 UTC): This daytime fireball generated 134 eyewitness reports on AMS report number 266 for 2016, with one credible sonic boom report. The fireball traveled roughly NE to SW with a terminus location north of Lake City, FL in sparsely populated, forested countryside. Radar imagery shows distinct and prominent evidence of a significant meteorite fall with radar signatures seen in data from the KJAX and KVAX radars. Searchers at the fall site found that recoveries were restricted to road sites by the difficult terrain, and yet several meteorites were recovered. Evidence indicates that this was a relatively large meteorite fall where most of the meteorites are unrecoverable due to terrain. Osceola is an L6 meteorite with 991 g total mass recovered to date. Mount Blanco, TX (18 Feb 2016 0343 UTC): This event produced only 39 eyewitness reports and is recorded as AMS event #635 for 2016. No

  20. Frost monitoring and forecasting using MODIS Land Surface Temperature data and a Numerical Weather Prediction model forecasts for Eastern Africa

    NASA Astrophysics Data System (ADS)

    Limaye, A. S.; Kabuchanga, E. S.; Flores, A.; Mungai, J.; Sakwa, V. N.; Shaka, A.; Malaso, S.; Irwin, D.

    2014-12-01

    Frost is a major challenge across Eastern Africa, severely impacting agriculture. Frost damages have wide ranging economic implications on tea and coffee farms, which represent a major economic sector. Early monitoring and forecasting will enable farmers to take preventive actions to minimize the losses. Although clearly important, timely information on when to protect crops from freezing is relatively limited. MODIS Land Surface Temperature (LST) data, derived from NASA's Terra and Aqua satellites, and 72-hr weather forecasts from the Kenya Meteorological Service's operational Weather Research Forecast model are enabling the Regional Center for Mapping of Resources for Development (RCMRD) and the Tea Research Foundation of Kenya to provide timely information to farmers in the region. This presentation will highlight an ongoing collaboration among the Kenya Meteorological Service, RCMRD, and the Tea Research Foundation of Kenya to identify frost events and provide farmers with potential frost forecasts in Eastern Africa.

  1. Frost Monitoring and Forecasting Using MODIS Land Surface Temperature Data and a Numerical Weather Prediction Model Forecasts for Eastern Africa

    NASA Technical Reports Server (NTRS)

    Kabuchanga, Eric; Flores, Africa; Malaso, Susan; Mungai, John; Sakwa, Vincent; Shaka, Ayub; Limaye, Ashutosh

    2014-01-01

    Frost is a major challenge across Eastern Africa, severely impacting agricultural farms. Frost damages have wide ranging economic implications on tea and coffee farms, which represent a major economic sector. Early monitoring and forecasting will enable farmers to take preventive actions to minimize the losses. Although clearly important, timely information on when to protect crops from freezing is relatively limited. MODIS Land Surface Temperature (LST) data, derived from NASA's Terra and Aqua satellites, and 72-hr weather forecasts from the Kenya Meteorological Service's operational Weather Research Forecast model are enabling the Regional Center for Mapping of Resources for Development (RCMRD) and the Tea Research Foundation of Kenya to provide timely information to farmers in the region. This presentation will highlight an ongoing collaboration among the Kenya Meteorological Service, RCMRD, and the Tea Research Foundation of Kenya to identify frost events and provide farmers with potential frost forecasts in Eastern Africa.

  2. Surface analysis and anti-graffiti behavior of a weathered polyurethane-based coating embedded with hydrophobic nano silica

    NASA Astrophysics Data System (ADS)

    Rabea, A. Mohammad; Mohseni, M.; Mirabedini, S. M.; Tabatabaei, M. Hashemi

    2012-03-01

    In this study, a permanent anti-graffiti polyurethane coating was prepared using concomitant loading of an OH-functional silicone modified polyacrylate additive ranging from 2 to 15 mol% and hydrophobic silica nanoparticles from 1 to 5 wt%. UV-visible spectroscopy, contact angle measurement and dynamic mechanical thermal analysis (DMTA) analysis were conducted on selected samples to study the weathering performance of samples containing various amounts of silica nanoparticles before and after accelerated weathering conditions. The results showed that higher amounts of additive had inferior effects on the anti-graffiti performance of the coating samples after exposure. However, silica nanoparticles could positively affect the anti-graffiti performance against ageing cycles. This improvement was attributed to lower degradation of samples containing silica nanoparticles and barrier property of nanoparticles against graffiti penetration. The presence of silica nanoparticles did not have any significant effect on the surface free energy of the samples prior and after ageing.

  3. Seasonal changes in Titan's weather patterns and the evolution and implications of accompanying surface changes

    NASA Astrophysics Data System (ADS)

    Turtle, E. P.; Perry, J.; McEwen, A. S.; Barbara, J. M.; Del Genio, A. D.; West, R. A.; Barnes, J. W.; Hayes, A.; Lorenz, R. D.; Lunine, J. I.; Stofan, E. R.; Schaller, E. L.; Lopes, R. M.; Ray, T. L.

    2012-12-01

    Post-equinox changes in Titan's atmospheric circulation brought clouds and extensive methane rain to Titan's low latitudes [1,2]. Observations by Cassini ISS over the ~2 years since the storm revealed most of the changes to be short-lived; only a few darkened patches persisted through Fall 2011. In an unsaturated permeable medium, infiltration rates exceed 20 mm/week [3], so persistence of surface liquids over several months suggests either a shallow impermeable layer or that the local methane table lies close to the surface. Evaporation rates greater than 1 mm/week are predicted in equatorial regions [4] and rates of 20 mm/week have been documented at Titan's poles [5], thus areas where darkening persisted must be saturated ground at the level of a methane table or have had liquid ponded to depths of 2.5-50 cm. Several smaller areas of surface brightening were also observed, a phenomenon that is less well understood. Cassini VIMS spectra of these regions do not match those of clouds or other surface units [6, 7]. Interpretations include cleaning by runoff [2] or deposition of a fine-grained volatile solid as the result of evaporative cooling [6, 7]. In general, brightening has persisted longer than darkening, but these areas are also reverting to their original appearance, which could constrain rates of evaporation/sublimation of the bright material or re-deposition of darker hydrocarbons by aeolian transport or precipitation from the atmosphere. Cassini and Earth-based observers monitor Titan frequently (typically at least a few times per month), but few clouds have been observed since Fall 2010, which may indicate that enough methane was removed from the atmosphere and the lapse rate stabilized sufficiently that activity will not resume until the onset of convection at mid-northern latitudes later in northern spring. A similar lapse followed a 2004 outburst of south-polar clouds [8], which also appeared to produce significant rainfall [9]. [1] Turtle et al., GRL

  4. Tracking tropical cloud systems - Observations for the diagnosis of simulations by the Weather Research and Forecasting (WRF) Model

    SciTech Connect

    Vogelmann, A.M.; Lin, W.; Cialella, A.; Luke, E.; Jensen, M.; Zhang, M.

    2010-03-15

    To aid in improving model parameterizations of clouds and convection, we examine the capability of models, using explicit convection, to simulate the life cycle of tropical cloud systems in the vicinity of the ARM Tropical Western Pacific sites. The cloud life cycle is determined using a satellite cloud tracking algorithm (Boer and Ramanathan, 1997), and the statistics are compared to those of simulations using the Weather Research and Forecasting (WRF) Model. Using New York Blue, a Blue Gene/L supercomputer that is co-operated by Brookhaven and Stony Brook, simulations are run at a resolution comparable to the observations. Initial results suggest a computational paradox where, even though the size of the simulated systems are about half of that observed, their longevities are still similar. The explanation for this seeming incongruity will be explored.

  5. The Role of Model and Initial Condition Error in Numerical Weather Forecasting Investigated with an Observing System Simulation Experiment

    NASA Technical Reports Server (NTRS)

    Prive, Nikki C.; Errico, Ronald M.

    2013-01-01

    A series of experiments that explore the roles of model and initial condition error in numerical weather prediction are performed using an observing system simulation experiment (OSSE) framework developed at the National Aeronautics and Space Administration Global Modeling and Assimilation Office (NASA/GMAO). The use of an OSSE allows the analysis and forecast errors to be explicitly calculated, and different hypothetical observing networks can be tested with ease. In these experiments, both a full global OSSE framework and an 'identical twin' OSSE setup are utilized to compare the behavior of the data assimilation system and evolution of forecast skill with and without model error. The initial condition error is manipulated by varying the distribution and quality of the observing network and the magnitude of observation errors. The results show that model error has a strong impact on both the quality of the analysis field and the evolution of forecast skill, including both systematic and unsystematic model error components. With a realistic observing network, the analysis state retains a significant quantity of error due to systematic model error. If errors of the analysis state are minimized, model error acts to rapidly degrade forecast skill during the first 24-48 hours of forward integration. In the presence of model error, the impact of observation errors on forecast skill is small, but in the absence of model error, observation errors cause a substantial degradation of the skill of medium range forecasts.

  6. Evolution of Titan's equinoctial weather patterns and accompanying surface changes and implications thereof

    NASA Astrophysics Data System (ADS)

    Turtle, E. P.; Perry, J. E.; Barnes, J. W.; McEwen, A. S.; Barbara, J. M.; Del Genio, A. D.; Hayes, A. G.; West, R. A.; Lorenz, R. D.; Schaller, E. L.; Lunine, J. I.; Ray, T. L.; Lopes, R. M. C.; Stofan, E. R.

    2012-04-01

    Post-equinox changes in Titan's atmospheric circulation brought clouds and extensive methane rain to Titan's low latitudes [1,2]. Observations by Cassini ISS over the ~1.5 years since the storm revealed most of the changes to be short-lived; only a few darkened patches persisted through Fall 2011. In an unsaturated permeable medium, infiltration rates are >20 mm/week [3], so persistence of surface liquids over several months suggests either a shallow impermeable layer or that the local methane table lies close to the surface. Evaporation rates >1 mm/week are predicted in equatorial regions [4] and rates of 20 mm/week have been documented at the poles [5], thus areas where darkening persisted must be saturated ground at the level of a methane table or have had liquid ponded to depths of 2.5-50 cm. Several smaller areas of surface brightening were also observed, a phenomenon that is less well understood. Cassini VIMS spectra of these regions do not match those of clouds or other surface units [6, 7]. Interpretations include cleaning by runoff [2] or deposition of fresh methane ice [6, 7]. In general, brightening has persisted longer than darkening, but these areas are also reverting to their original appearance, which could constrain the rate of re-deposition of darker hydrocarbon materials by aeolian transport or possibly precipitation of aerosols from the atmosphere. Although we monitor Titan frequently (at least a few times per month), little cloud activity has been observed since Fall 2010. This lack of clouds may indicate that the outbreak removed enough methane from the atmosphere and the lapse rate stabilized sufficiently that activity will not resume until the onset of convection at mid-northern latitudes later in northern spring. A similar lapse followed a large outbreak of south-polar clouds in Fall 2004 [8], which also appeared to produce significant rainfall [9]. References: [1] Turtle et al., GRL 38, L03203, doi: 10.1029/2010GL046266, 2011. [2] Turtle et

  7. Evaluating the Impacts of NASA/SPoRT Daily Greenness Vegetation Fraction on Land Surface Model and Numerical Weather Forecasts

    NASA Technical Reports Server (NTRS)

    Bell, Jordan R.; Case, Jonathan L.; LaFontaine, Frank J.; Kumar, Sujay V.

    2012-01-01

    The NASA Short-term Prediction Research and Transition (SPoRT) Center has developed a Greenness Vegetation Fraction (GVF) dataset, which is updated daily using swaths of Normalized Difference Vegetation Index data from the Moderate Resolution Imaging Spectroradiometer (MODIS) data aboard the NASA EOS Aqua and Terra satellites. NASA SPoRT began generating daily real-time GVF composites at 1-km resolution over the Continental United States (CONUS) on 1 June 2010. The purpose of this study is to compare the National Centers for Environmental Prediction (NCEP) climatology GVF product (currently used in operational weather models) to the SPoRT-MODIS GVF during June to October 2010. The NASA Land Information System (LIS) was employed to study the impacts of the SPoRT-MODIS GVF dataset on a land surface model (LSM) apart from a full numerical weather prediction (NWP) model. For the 2010 warm season, the SPoRT GVF in the western portion of the CONUS was generally higher than the NCEP climatology. The eastern CONUS GVF had variations both above and below the climatology during the period of study. These variations in GVF led to direct impacts on the rates of heating and evaporation from the land surface. In the West, higher latent heat fluxes prevailed, which enhanced the rates of evapotranspiration and soil moisture depletion in the LSM. By late Summer and Autumn, both the average sensible and latent heat fluxes increased in the West as a result of the more rapid soil drying and higher coverage of GVF. The impacts of the SPoRT GVF dataset on NWP was also examined for a single severe weather case study using the Weather Research and Forecasting (WRF) model. Two separate coupled LIS/WRF model simulations were made for the 17 July 2010 severe weather event in the Upper Midwest using the NCEP and SPoRT GVFs, with all other model parameters remaining the same. Based on the sensitivity results, regions with higher GVF in the SPoRT model runs had higher evapotranspiration and

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

    NASA Technical Reports Server (NTRS)

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

    1986-01-01

    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.

  9. The Surface of Titan: Arecibo Radar Observations

    NASA Technical Reports Server (NTRS)

    Campbell, D. B.; Black, G. J.; Carter, L. M.; Hine, A. A.; Margot, J. L.; Nolan, M. C.; Ostro, S. J.

    2002-01-01

    The Arecibo 12.6 cm radar system was used to observe Titan in 1999, 2000 and 2001. The mean value of the radar albedo is 0.16 and the polarization ratio is 0.35. For some longitudes the echo has a specular component although most of the echo power is contained in a diffuse component. Additional information is contained in the original extended abstract.

  10. Sea surface temperature - Observations from geostationary satellites

    NASA Technical Reports Server (NTRS)

    Bates, J. J.; Smith, W. L.

    1985-01-01

    Multispectral image data acquired from the VISSR atmospheric sounder (VAS) on the geostationary GOES satellites were used to estimate sea surface temperatures (SST). A procedure was developed to screen VAS visible and infrared data for cloud-free regions for estimation of SST from the clear infrared radiances. A data set of matches between the VAS radiances and high quality buoy estimates of SST was produced. A linear regression analysis of these matches was performed to generate an empirical algorithm relating the VAS window channel brightness temperatures to the estimates of SST recorded by NOAA fixed environment buoys. Daily maps of SST during Hurricanes Alicia (1983) and Debbie (1982) demonstrated the ability of VAS to monitor air-sea interactions at high temporal and spatial scales.

  11. Ground-based microwave weather radar observations and retrievals during the 2014 Holuhraun eruption (Bárðarbunga, Iceland)

    NASA Astrophysics Data System (ADS)

    Mereu, Luigi; Silvio Marzano, Frank; Barsotti, Sara; Montopoli, Mario; Yeo, Richard; Arngrimsson, Hermann; Björnsson, Halldór; Bonadonna, Costanza

    2015-04-01

    During an eruptive event the real-time forecasting of ash dispersal into the atmosphere is a key factor to prevent air traffic disasters. The ash plume is extremely hazardous to aircraft that inadvertently may fly through it. Real-time monitoring of such phenomena is crucial, particularly to obtain specific data for the initialization of eruption and dispersion models in terms of source parameters. The latter, such as plume height, ash concentration, mass flow rate and size spectra, are usually very difficult to measure or to estimate with a relatively good accuracy. Over the last years different techniques have been developed to improved ash plume detection and retrieval. Satellite-based observations, using multi-frequency visible and infrared radiometers, are usually exploited for monitoring and measuring dispersed ash clouds. The observations from geostationary orbit suffer from a relatively poor spatial resolution, whereas the low orbit level has a relatively poor temporal resolution. Moreover, the field-of-view of infrared radiometric measurements may be reduced by obstructions caused by water and ice clouds lying between the ground and the sensor's antenna. Weather radar-based observations represent an emerging technique to detect and, to a certain extent, mitigate the hazard from the ash plumes. Ground-based microwave scanning radar systems can provide the three-dimensional information about the detected ash volume with a fairly high spatial resolution every few minutes and in all weather conditions. Methodological studies have recently investigated the possibility of using single-polarization and dual-polarization ground-based radar for the remote sensing of volcanic ash cloud. In this respect, radar observations can be complementary to satellite observations. A microphysical electromagnetic characterization of volcanic ash was carried out in terms of dielectric properties, composition, size and orientation of ash particles. An extended Volcanic Ash Radar

  12. Matching Observations to Model Resolution for Future Weather and Climate Applications

    NASA Technical Reports Server (NTRS)

    Pagano, Thomas S.

    2008-01-01

    High spatial resolution sounding observations will improve initialization and assimilation into the next generation forecast models and validation of the next generation of climate models. One such advanced sounder concept for low earth orbit is the Advanced Remote-sensing Imaging Emission Spectrometer (ARIES) which proposes to provide highvspatial hyperspectral resolution observations in the mid to longwave infrared. This paper explores the effects of spatial resolution on the errors expected from the combined use of models and observations for representing scene information. We calculate the frequency response of the instrument and model and determine the error at any given spatial frequency. The results show that it is vital to have observations match the spatial resolution of models to minimize the uncertainty in the representation of the scene contents.

  13. Evaluation of Integrated Multi-satellitE Retrievals for GPM with All Weather Gauge Observations over CONUS

    NASA Astrophysics Data System (ADS)

    Chen, S.; Qi, Y.; Hu, B.; Hu, J.; Hong, Y.

    2015-12-01

    The Global Precipitation Measurement (GPM) mission is composed of an international network of satellites that provide the next-generation global observations of rain and snow. Integrated Multi-satellitE Retrievals for GPM (IMERG) is the state-of-art precipitation products with high spatio-temporal resolution of 0.1°/30min. IMERG unifies precipitation measurements from a constellation of research and operational satellites with the core sensors dual-frequency precipitation radar (DPR) and microwave imager (GMI) on board a "Core" satellite. Additionally, IMERG blends the advantages of currently most popular satellite-based quantitative precipitation estimates (QPE) algorithms, i.e. TRMM Multi-satellite Precipitation Analysis (TMPA), Climate Prediction Center morphing technique (CMORPH), Precipitation Estimation from Remotely Sensed Information using Artificial Neural Networks-Cloud Classification System (PERSIANN-CCS). The real-time and post real-time IMERG products are now available online at https://stormpps.gsfc.nasa.gov/storm. In this study, the final run post real-time IMERG is evaluated with all-weather manual gauge observations over CONUS from June 2014 through May 2015. Relative Bias (RB), Root-Mean-Squared Error (RMSE), Correlation Coefficient (CC), Probability Of Detection (POD), False Alarm Ratio (FAR), and Critical Success Index (CSI) are used to quantify the performance of IMERG. The performance of IMERG in estimating snowfall precipitation is highlighted in the study. This timely evaluation with all-weather gauge observations is expected to offer insights into performance of IMERG and thus provide useful feedback to the algorithm developers as well as the GPM data users.

  14. PV powering a weather station for severe weather

    SciTech Connect

    Young, W. Jr.; Schmidt, J.

    1997-12-31

    A natural disaster, such as Hurricane Andrew, destroys thousands of homes and businesses. The destruction from this storm left thousands of people without communications, potable water, and electrical power. This prompted the Florida Solar Energy Center to study the application of solar electric power for use in disasters. During this same period, volunteers at the Tropical Prediction Center at the National Hurricane Center (NHC), Miami, Florida and the Miami Office of the National Weather Service (NWS) were working to increase the quantity and quality of observations received from home weather stations. Forecasters at NHC have found surface reports from home weather stations a valuable tool in determining the size, strength and course of hurricanes. Home weather stations appear able to record the required information with an adequate level of accuracy. Amateur radio, utilizing the Automatic Packet Report System, (APRS) can be used to transmit this data to weather service offices in virtually real time. Many weather data collecting stations are at remote sites which are not readily serviced by dependable commercial power. Photovoltaic (solar electric) modules generate electricity and when connected to a battery can operate as a stand alone power system. The integration of these components provides an inexpensive standalone system. The system is easy to install, operates automatically and has good communication capabilities. This paper discusses the design criteria, operation, construction and deployment of a prototype solar powered weather station.

  15. The influence of dynamic vegetation models including harvest and fertilization management on the energy fluxes and the feedback effects between the weather and the land surface models

    NASA Astrophysics Data System (ADS)

    Klein, Christian; Biernath, Christian; Thieme, Christoph; Heinlein, Florian; Priesack, Eckart

    2014-05-01

    Recent studies show that uncertainties in regional and global weather and climate simulations are partly caused by inadequate descriptions of the soil-plant-atmosphere system. Particularly relevant for the improvement of regional weather forecast are models which better describe the feedback fluxes between the land surface and the atmosphere, which influences surface temperature, surface air pressure and the amount and frequency of precipitation events. Aim of this study was to examine the differences between weather simulation results by the "Regional Climate and Weather Forecast Model" (WRF) using either the frequently applied land surface model NOAH or Expert-N. Where the standard model NOAH distinguish between vegetation class specific monthly changing soil cover values (leaf area index) and defined soil characteristics, Expert-N is an ecosystem model that allows the application of more mechanistic soil and plant sub-models including the management of soil and vegetation and effects of water and nutrient availability on plant growth are considered. The WRF-NOAH model was applied with a default land surface configuration typical for the simulation domain Bavaria, Germany. Expert-N was configured using the Hurley Pasture Model to simulate plant growth and calibrated using vegetation, management and soil data from one grassland site. Both models were applied to the simulation domain. The simulation results of energy fluxes in both models between the land surface and the atmosphere were compared with each other's and with weather data from about 100 weather stations in Bavaria using statistical methods. The influence of different harvest scenarios on the energy fluxes is discussed. The simulation shows the high impact of vegetation management on the energy fluxes which caused significant differences between weather characteristics such as the simulated surface temperatures and precipitation events on the regional scale. Therefore, we conclude that weather forecast

  16. Modelling surface roughness and rocks in LRO Diviner observations

    NASA Astrophysics Data System (ADS)

    Williams, J.-P.; Hayne, P. O.; Paige, D. A.

    2012-09-01

    The Diviner Lunar Radiometer Experiment on NASA's Lunar Reconnaissance Orbiter (LRO) observes radiance in 7 infrared spectral channels from which brightness temperatures of the lunar surface are derived. In general, Diviner's surface footprint contains small scale variations in temperature. This anisothermality results in different observed brightness temperatures in Diviner's individual channels. A three-dimensional heat diffusion model is used to explore anisothermality in Diviner observations resulting from surface roughness and rocks at multiple length-scales and illumination conditions.

  17. Space Weathering Processes on Mercury

    NASA Technical Reports Server (NTRS)

    Noble, S. K.; Pieters, C. M.

    2002-01-01

    Like the Moon, Mercury has no atmosphere to protect it from the harsh space environment and therefore it is expected that it will incur the effects of space weathering. These weathering processes are capable of both creating regolith and altering its optical properties. However, there are many important differences between the environments of Mercury and the Moon. These environmental differences will almost certainly affect the weathering processes as well as the products of those processes. It should be possible to observe the effects of these differences in Vis/NIR spectra of the type expected to be returned by MESSENGER. More importantly, understanding these weathering processes and their consequences is essential for evaluating the spectral data returned from MESSENGER and other missions in order to determine the mineralogy and the iron content of the Mercurian surface. Theoretical and experimental work has been undertaken in order to better understand these consequences.

  18. Micro-mapping Meteorite Surfaces on Mars using Microscopic Imager Mosaics — A Tool for Unraveling Weathering History at Meridiani Planum

    NASA Astrophysics Data System (ADS)

    Ashley, J. W.; Herkenhoff, K. E.; Golombek, M. P.; Johnson, J. R.

    2012-12-01

    Meteorites found on Mars provide valuable insights into martian surface processes. During the course of Mars Exploration Rover (MER) extended missions, Spirit and Opportunity have identified 17 confirmed and candidate meteorites on Mars, most of which are irons. The iron meteorites exhibit morphologies and coatings that communicate complex post-fall exposure histories relevant to an understanding of climate near the martian equator [1-4]. Both chemical and mechanical weathering effects are represented. Among the more significant of these are: 1) cm-scale hollowing, 2) surficial rounding, 3) mass excavation/dissolution and removal, 4) differential etching of kamacite plates and taenite lamellae, revealing Widmanstätten patterns, 5) discontinuous iron oxide coatings, and 6) the effects of cavernous weathering, which often penetrate to rock interiors. Determining the nature, magnitude, and timing of each process and its associated features is a complex problem that will be aided by laboratory experiments, image processing, and careful surface evaluation. Because some features appear to superpose others in ways analogous to stratigraphic relationships, Microscopic Imager (MI) mosaics are useful for sketching "geologic maps" of meteorite surfaces. Employing the techniques of conventional planetary mapping [5], each map was drafted manually using full-resolution MI mosaics and Adobe Photoshop software. Units were selected to represent the oxide coating, dust-coated surfaces, sand-coated surfaces, taenite lamellae, and uncoated metal. Also included are areas in shadow, and regions of blooming caused by specular reflection of metal. Regmaglypt rim crests are presented as lineations. As with stratigraphic relationships, noting embayments and other cross-cutting relationships assists with establishing the relative timing for observed weathering effects. In addition to suggesting alternating sequences of wind and water exposure [1], patterns in oxide coating occurrence show

  19. Simulation and Observation of Global Variations in Surface Exchange and Atmospheric Mixing Ratios of CO2

    NASA Astrophysics Data System (ADS)

    Denning, A.; Conner-Gausepohl, S.; Kawa, S.; Baker, I. T.; Zhu, Z.; Brown, M.; Vay, S.; Wofsy, S. C.; Philpott, A.; Collatz, G.; Schaefer, K.; Kleist, J.

    2005-12-01

    We have performed a simulation of hourly variations of terrestrial surface fluxes and the atmospheric mixing ratio of carbon dioxide from January 1, 2000 through December 31, 2004, and have evaluated the simulation by comparison to a number of observations. Terrestrial photosynthesis and ecosystem respiration were computed using the Simple Biosphere Model (SiB), driven by diurnally-varying weather analyzed by the NASA Goddard Earth Observing System (GEOS) Data Assimilation System (DAS), with vegetation parameters specified using imagery from the NOAA Advanced High Resolution Radiometer (AVHRR). CO2 emissions due to the combustion of fossil fuel and to air-sea gas exchange were also prescribed as boundary forcing to the atmospheric transport Parameterized Chemical Transport model (PCTM). Preliminary results showed reasonable agreement with spatial and synoptic variations, but suffered from a systematic offset with respect to the observed seasonal cycle of CO2 at many flask observing stations. Subsequent analysis showed that these problems were traceable to temporal interpolation of the satellite vegetation imagery and the treatment of leaf-to-canopy scaling in SiB, which have both been substantially revised as a result of these analyses. Comparisons to eddy covariance data at several sites, to tower-based continuous observations of CO2 mixing ratio, and to data collected by airborne sampling show that the coupled simulation successfully captures many features of the observed temporal and spatial variations of terrestrial surface exchange and atmospheric transport of CO2. The simulations demonstrate the sensitivity of both surface exchange and atmospheric transport of CO2 to synoptic weather events in middle latitudes, and suggest that high-frequency variations in continental [CO2] data can be interpreted in terms of surface flux anomalies.

  20. Solid Surface Combustion Experiment Yields Significant Observations

    NASA Technical Reports Server (NTRS)

    Sacksteder, Kurt R.; Koudelka, John M.; Vergilii, Franklin

    1999-01-01

    The spread of a flame over solid fuel is not only a fundamental textbook combustion phenomenon, but also the central element of destructive fires that cause tragic loss of life and property each year. Throughout history, practical measures to prevent and fight fires have been developed, but these have often been based on lessons learned in a costly fire. Since the 1960 s, scientists and engineers have employed powerful tools of scientific research to understand the details of flame spread and how a material can be rendered nonflammable. High-speed computers have enabled complex flame simulations, whereasand lasers have provided measurements of the chemical composition, temperature, and air velocities inside flames. The microgravity environment has emerged as the third great tool for these studies. Spreading flames are complex combinations of chemical reactions and several physical processes including the transport of oxygen and fuel vapor to the flame and the transfer of heat from the flame to fresh fuel and to the surroundings. Depending on its speed, air motion in the vicinity of the flame can affect the flame in substantially different ways. For example, consider the difference between blowing on a campfire and blowing out a match. On Earth, gravity induces air motion because of buoyancy (the familiar rising hot gases); this process cannot be controlled experimentally. For theoreticians, buoyant air motion complicates the problem modeling of flame spread beyond the capacity of modern computers to simulate. The microgravity environment provides experimental control of air motion near spreading flames, with results that can be compared with detailed theory. The Solid Surface Combustion Experiment (SSCE) was designed to obtain benchmark flame spreading data in quiescent test atmospheres--the limiting case of flames spreading. Professor Robert Altenkirch, Vice President for Research at Mississippi State University, proposed the experiment concept, and the NASA Lewis

  1. A Global Analysis of the ZWD/PW Conversion Methods using Radiosonde Observations and Numerical Weather Models

    NASA Astrophysics Data System (ADS)

    Rozsa, S.

    2014-12-01

    Water vapor plays an important role as a basic climate variable in the thermodynamics and dynamics of the storm systems at the atmosphere and in hydrological cycles of local, regional and global scales. Moreover, the distribution of atmospheric water vapor is difficult to determine because of its rapid change in spatial and temporal scales. Atmospheric water vapor can be estimated by the zenith delay derived from ground-based GNSS data. Ground-based GNSS receivers are a valuable source for determining total zenith delay (ZTD) and precipitable water vapor (PW) data for meteorology since they are portable, economic and provide measurements that are not affected by weather conditions. They cannot provide a humidity profile as radiosondes can, however they have the advantage of producing automated continuous data as opposed to operational radiosondes usually providing two measurements in a day. Therefore, tropospheric delay modeling methods for estimating precipitable water vapor using GNSS signals are being developed frequently. Wet and hydrostatic zenith delays can be computed by applying the mapping functions which are mathematical equations using elevation angles. The observed tropospheric delays can be used for monitoring the water vapor content of the troposphere. In several regions of the world GNSS derived products are already used on a routine basis for numerical weather prediction. In this study, PW values obtained from radiosonde profiles and the ones derived from ground-based GNSS data are processed both with BERNESE v5.0 using Niell mapping function and GAMIT/GLOBK using empirical model GPT (Global Pressure and Temperature) are compared with the values computed from radiosonde analysis algorithm under severe storm conditions. In order to convert the ZWD to PW new, locally fitted models are derived using local radiosonde observations and ECMWF model data.

  2. Observations of fair-weather cumuli over land: Dynamical factors controlling cloud size and cover

    NASA Astrophysics Data System (ADS)

    Lamer, Katia; Kollias, Pavlos

    2015-10-01

    Comprehensive observations of shallow convection at the Atmospheric Radiation Measurement Southern Great Plains site are carefully analyzed to study the macrophysical and dynamical properties of active and forced cumuli separately and investigate their relationship to the subcloud layer turbulent structure. Clearly, active clouds possess stronger dynamics and greater horizontal extent than their forced counterpart. As previously reported, upper level stability and relative humidity do control the predominance of active clouds. While cloud cover remains difficult to associate to mixed-layer parameters (small correlation coefficients), mixed-layer top vertical velocity skewness, and coherent updraft fraction most significantly correlate to cumulus cloud cover and especially the portion attributed to active clouds; both of which are not currently considered in shallow cloudiness parameterizations. This study also points to several factors that continue to limit our ability to adequately sample shallow cumuli and suggests that forward models will be necessary to bridge observations and model outputs.

  3. Doppler weather radar observations of the 2009 eruption of Redoubt Volcano, Alaska

    USGS Publications Warehouse

    Schneider, David J.; Hoblitt, Richard P.

    2013-01-01

    The U.S. Geological Survey (USGS) deployed a transportable Doppler C-band radar during the precursory stage of the 2009 eruption of Redoubt Volcano, Alaska that provided valuable information during subsequent explosive events. We describe the capabilities of this new monitoring tool and present data captured during the Redoubt eruption. The MiniMax 250-C (MM-250C) radar detected seventeen of the nineteen largest explosive events between March 23 and April 4, 2009. Sixteen of these events reached the stratosphere (above 10 km) within 2–5 min of explosion onset. High column and proximal cloud reflectivity values (50 to 60 dBZ) were observed from many of these events, and were likely due to the formation of mm-sized accretionary tephra-ice pellets. Reflectivity data suggest that these pellets formed within the first few minutes of explosion onset. Rapid sedimentation of the mm-sized pellets was observed as a decrease in maximum detection cloud height. The volcanic cloud from the April 4 explosive event showed lower reflectivity values, due to finer particle sizes (related to dome collapse and related pyroclastic flows) and lack of significant pellet formation. Eruption durations determined by the radar were within a factor of two compared to seismic and pressure-sensor derived estimates, and were not well correlated. Ash dispersion observed by the radar was primarily in the upper troposphere below 10 km, but satellite observations indicate the presence of volcanogenic clouds in the stratosphere. This study suggests that radar is a valuable complement to traditional seismic and satellite monitoring of explosive eruptions.

  4. Coastal Observations of Weather Features in Senegal during the AMMA SOP-3 Period

    NASA Technical Reports Server (NTRS)

    Jenkins, G.; Kucera, P.; Joseph, E.; Fuentes, J.; Gaye, A.; Gerlach, J.; Roux, F.; Viltard, N.; Papazzoni, M.; Protat, A.; Bouniol, D.; Reynolds, A.; Arnault, J.; Badiane, D.; Kebe, F.; Camara, M.; Sall, S.

    2009-01-01

    During 15 August through 30 September 2006, ground and aircraft measurements were obtained from a multi-national group of students and scientists in Senegal. Key measurements were aimed at investigating and understanding precipitation processes, thermodynamic and dynamic environmental conditions, cloud, aerosol and microphysical processes and spaceborne sensors (TRMM, CloudSat/Calipso) validation. Ground and aircraft instruments include: ground based polarimetric radar, disdrometer measurements, a course and a high-density rain gauge network, surface chemical measurements, a 10 m flux tower, broadband IR, solar and microwave measurements, rawinsonde and radiosonde measurements, FA-20 dropsonde, in situ microphysics and cloud radar measurements. Highlights during SOP3 include ground and aircraft measurements of squall lines, African Easterly Waves (AEWs), Saharan Air Layer advances into Senegal, and aircraft measurements of AEWs -- including the perturbation that became Hurricane Isaac.

  5. Low cloud type over the ocean from surface observations. Part 1: Relationship to surface meteorology and the vertical distribution of temperature and moisture

    SciTech Connect

    Norris, J.R.

    1998-03-01

    Surface cloud observations and coincident surface meteorological observations and soundings from five ocean weather stations are used to establish representative relationships between low cloud type and marine boundary layer (MBL) properties for the subtropics and midlatitudes by compositing soundings and meteorological observations for which the same low cloud type was observed. Physically consistent relationships are found to exist between low cloud type, MBL structure, and surface meteorology at substantially different geographical locations and seasons. Relative MBL height and inferred decoupling between subcloud and cloud layers are increasingly greater for stratocumulus, cumulus-under-stratocumulus, and cumulus, respectively, at midlatitude locations as well as the eastern subtropical location during both summer and winter. At the midlatitude locations examined, cloudiness identified as fair-weather stratus often occurs in a deep, stratified cloud layer with little or no capping inversion. This strongly contrasts with cloudiness identified as stratocumulus, which typically occurs in a relatively well-mixed MBL under a strong capping inversion at both midlatitude and eastern subtropical locations. At the transition between subtropics and midlatitudes in the western North Pacific, cloudiness identified as fair-weather stratus occurs in a very shallow layer near the surface. Above this layer the associated profile of temperature and moisture is similar to that for cumulus at the same location, and neither of these cloud types is associated with a discernible MBL. Sky-obscuring fog and observations of no low cloudiness typically occur with surface-based inversions. These observed relationships can be used in future studies of cloudiness and cloudiness variability to infer processes and MBL structure where above-surface observations are lacking. 42 refs., 6 figs., 4 tabs.

  6. Color changes in objects in natural scenes as a function of observation distance and weather conditions.

    PubMed

    Romero, Javier; Luzón-González, Raúl; Nieves, Juan L; Hernández-Andrés, Javier

    2011-10-01

    We have analyzed the changes in the color of objects in natural scenes due to atmospheric scattering according to changes in the distance of observation. Hook-shaped curves were found in the chromaticity diagram when the object moved from zero distance to long distances, where the object chromaticity coordinates approached the color coordinates of the horizon. This trend is the result of the combined effect of attenuation in the direct light arriving to the observer from the object and the airlight added during its trajectory. Atmospheric scattering leads to a fall in the object's visibility, which is measurable as a difference in color between the object and the background (taken here to be the horizon). Focusing on color difference instead of luminance difference could produce different visibility values depending on the color tolerance used. We assessed the cone-excitation ratio constancy for several objects at different distances. Affine relationships were obtained when an object's cone excitations were represented both at zero distance and increasing distances. These results could help to explain color constancy in natural scenes for objects at different distances, a phenomenon that has been pointed out by different authors. PMID:22016233

  7. In situ observations from STEREO/PLASTIC: a test for L5 space weather monitors

    NASA Astrophysics Data System (ADS)

    Simunac, K. D. C.; Kistler, L. M.; Galvin, A. B.; Popecki, M. A.; Farrugia, C. J.

    2009-10-01

    Stream interaction regions (SIRs) that corotate with the Sun (corotating interaction regions, or CIRs) are known to cause recurrent geomagnetic storms. The Earth's L5 Lagrange point, separated from the Earth by 60 degrees in heliographic longitude, is a logical location for a solar wind monitor - nearly all SIRs/CIRs will be observed at L5 several days prior to their arrival at Earth. Because the Sun's heliographic equator is tilted about 7 degrees with respect to the ecliptic plane, the separation in heliographic latitude between L5 and Earth can be more than 5 degrees. In July 2008, during the period of minimal solar activity at the end of solar cycle 23, the two STEREO observatories were separated by about 60 degrees in longitude and more than 4 degrees in heliographic latitude. This time period affords a timely test for the practical application of a solar wind monitor at L5. We compare in situ observations from PLASTIC/AHEAD and PLASTIC/BEHIND, and report on how well the BEHIND data can be used as a forecasting tool for in situ conditions at the AHEAD spacecraft with the assumptions of ideal corotation and minimal source evolution. Preliminary results show the bulk proton parameters (density and bulk speed) are not in quantitative agreement from one observatory to the next, but the qualitative profiles are similar.

  8. Detection of Rain-on-Snow (ROS) Events Using the Advanced Microwave Scanning Radiometer-Earth Observing System (AMSR-E) and Weather Station Observations

    NASA Astrophysics Data System (ADS)

    Ryan, E. M.; Brucker, L.; Forman, B. A.

    2015-12-01

    During the winter months, the occurrence of rain-on-snow (ROS) events can impact snow stratigraphy via generation of large scale ice crusts, e.g., on or within the snowpack. The formation of such layers significantly alters the electromagnetic response of the snowpack, which can be witnessed using space-based microwave radiometers. In addition, ROS layers can hinder the ability of wildlife to burrow in the snow for vegetation, which limits their foraging capability. A prime example occurred on 23 October 2003 in Banks Island, Canada, where an ROS event is believed to have caused the deaths of over 20,000 musk oxen. Through the use of passive microwave remote sensing, ROS events can be detected by utilizing observed brightness temperatures (Tb) from AMSR-E. Tb observed at different microwave frequencies and polarizations depends on snow properties. A wet snowpack formed from an ROS event yields a larger Tb than a typical dry snowpack would. This phenomenon makes observed Tb useful when detecting ROS events. With the use of data retrieved from AMSR-E, in conjunction with observations from ground-based weather station networks, a database of estimated ROS events over the past twelve years was generated. Using this database, changes in measured Tb following the ROS events was also observed. This study adds to the growing knowledge of ROS events and has the potential to help inform passive microwave snow water equivalent (SWE) retrievals or snow cover properties in polar regions.

  9. Plasmon Surface Polariton Dispersion by Direct Optical Observation.

    ERIC Educational Resources Information Center

    Swalen, J. D.; And Others

    1980-01-01

    Describes several simple experiments that can be used to observe directly the dispersion curve of plasmon surface polaritons (PSP) on flat metal surfaces. A method is described of observing the increonental change in the wave vector of the PSP due to coatings that differ in thickness by a few nanometers. (Author/CS)

  10. Age calibration of weathering fractures in desert clasts: A new approach to dating geomorphic surfaces in arid landscapes

    NASA Astrophysics Data System (ADS)

    D'Arcy, Mitch; Roda Boluda, Duna; Whittaker, Alex

    2014-05-01

    Advances in geomorphological and sedimentological research depend on the availability of reliable exposure age constraints. Establishing robust age models at a high spatial and temporal resolution is crucial for measuring rates of geomorphological change and decoding complex landscapes shaped by time-dependent forces, e.g. climate fluctuations. A number of isotopic and luminescence techniques are now available for dating geomorphic surfaces, however they remain expensive and time-consuming to deploy with detailed coverage over space and time in many study areas. For this reason, quick and accessible methods for correlating and extrapolating these chronologies are needed. In arid landscapes, among others, a variety of weathering-induced changes occur to geomorphic and sedimentary surfaces, and many of these processes occur at predictable rates and can be quantified using objective, field based measurements. One example is the gradual widening of fractures that exist within boulders on desert surfaces, by a combination of processes including salt weathering and freeze-thaw cycles. The recent emergence of very detailed exposure age models in a number of locations means it is now possible to measure the rates of desert weathering processes, and use them as fully calibrated age indicators themselves. With the potential to significantly extend the coverage of existing age constraints, this kind of quantitative age correlation would enable a broad range of geomorphological and sedimentological research that depends on detailed absolute age models. We have measured the mean widths of hundreds of vertical fractures that dissect granitic boulders, on a variety of alluvial surfaces in Owens Valley, California, which have themselves been independently dated in detail using cosmogenic nuclides. Our data demonstrates for the first time that these fractures widen at a predictable, steady rate of approximately 1 mm ka-1 for at least the last 150 ka, in this arid study area in the

  11. Space Weathering of Rocks

    NASA Technical Reports Server (NTRS)

    Noble, Sarah

    2011-01-01

    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.

  12. Using shallow seismic tomography to characterize patterns of near-surface weathering and the mobile-immobile regolith transition: Implications for the erodibility and morphology of hillslopes.

    NASA Astrophysics Data System (ADS)

    Clarke, B. A.; Kirby, E.; Burbank, D. W.; West, N.

    2014-12-01

    We use 2D tomography of P- and S-wave velocities (Vp, Vs), based on seismic refraction and surface wave analyses, to characterize subsurface architecture and erodibility of hillslopes. Calibrating the seismic imagery with direct field observations allows us to quantify mechanical properties, image depth-dependent variations in weathering intensity, and identify the mobile-immobile regolith transition and differences in transport efficiency of mobile layers. We conducted a cross-CZO comparison of N- and S-facing slopes at Boulder Creek and Shale Hills CZOs (BcCZO and SSHCZO) to investigate how near-surface weathering and hillslope morphology are influenced by differences in regional geology and climatic as well as local variations in aspect-controlled microclimate. Niwot Ridge (BcCZO) is a high alpine site with minimal soil/veg cover, characterized by steeper S-facing hillslopes; whereas, SSHCZO is a temperate, densely-forested, soil-mantled site with steeper N-facing slopes. On Niwot Ridge, the depth of the weathering front and thickness of mobile regolith are substantially greater on shallower N-facing slopes; however, velocity-based estimates of transport efficiency are higher on S-facing slopes. Although, thin mobile regolith on S-facing slopes may be weaker (slower V), the lower gradient of N-facing slopes and southward asymmetry of the ridge divide, suggests greater transport efficiency on N-facing aspects. This can be explained by the dominance of frost/freeze process on N-facing slopes, which can efficiently develop and transport the thick mobile regolith. At SSHCZO, depths of weathering fronts are invariant with slope aspect, suggesting that aspect control is not a predominant mechanism driving regolith production. Mobile regolith thickness, however, is more than 2-fold greater on N-facing slopes. Additionally, mobile regolith on both slope aspects is primarily composed of well-developed soils. N-facing soils are thicker with greater cohesion, moisture, and

  13. Deeply weathered basement rocks in Norway

    NASA Astrophysics Data System (ADS)

    Bönner, Marco; Knies, Jochen; Fredin, Ola; Olesen, Odleiv; Viola, Giulio

    2014-05-01

    Recent studies show that, in addition to tectonic processes, surface processes have also had a profound impact on the topography of Norway. This is especially obvious for the northernmost part of the Nordland county and for western Norway, where the current immature Alpine-type topography cannot be easily explained by tectonic processes only. Erosion of the sedimentary succession also does not seem sufficient to explain the observed relief. Common remnants of deeply weathered basement rocks, however, indicate a history of deep alteration and later erosion of the bedrock, which needs to be considered as another important factor in the development of the topographic relief. Most of the sites with deeply weathered basement exhibit a clay-poor grussy type of weathering, which is generally considered to be of relatively young age (Plio-/Pleistocene) and thought to represent an intermediate stage of weathering. Unfortunately, small amounts or complete absence of clay minerals in these weathering products precluded the accurate dating of this weathered material. Scandinavia was exposed to a large range of glaciations and the once extensive sedimentary successions have been almost entirely eroded, which impedes a minimum age estimate of the weathering profile. Although several sites preserving remnants of deep weathering can still be observed onshore Norway, they are all covered by Quaternary overburden and the age of the regolith remains thus unconstrained and a matter of debate. The only exception is a small Mesozoic basin on Andøya, northern Norway, where weathered and clay-poor saprolite was found underlying Jurassic and Cretaceous sedimentary rocks. Over the last few years the Geological Survey of Norway (NGU) has mapped and investigated deep weathering onshore Norway to better understand weathering processes and to constrain the age of the weathering remnants. The combined interpretation of geophysical, mineralogical and geochemical data, together with recent

  14. Estimation of planetary surface roughness by HF sounder observation

    NASA Astrophysics Data System (ADS)

    Kobayashi, T.; Ono, T.

    Japanese Martian exploration project "Nozomi" was to carry out several science missions. Plasma Wave Sounder, one of those onboard missions, was an HF sounder to study Martian plasma environment, and Martian surface with the altimetry mode (Oya and Ono, 1998) as well. The altimetry mode observation was studied by means of computer simulations utilizing the KiSS code which had been originally designed to simulate the SELENE Lunar Radar Sounder, a spaceborne HF GPR, based on Kirchhoff approximation theory (Kobayashi, Oya and Ono, 2002). We found an empirical power law for the standard deviation of observed altitudes over Gaussian random rough surfaces: it varies in proportion to the square of the RMS gradient of the surface √{2} hRMS{λ_0, where hRMS and λ_0 are the RMS height of the surface and the correlation distance of the surface, respectively. We applied Geometrical optics to understand this empirical power law, and derived a square power law for the standard deviation of the observed altitude. Our Geometrical optics model assumed the followings: 1) the observed surface is a Gaussian random rough surface, 2) the mean surface is a flat horizontal plane, 3) the observed surface echo is the back scattering echoes, 4) the observed altitude is the mean value of the apparent range of those back scattering echoes. These results imply that HF sounder may be utilized to measure the surface roughness of planetary bodies in terms of the RMS gradient of the surface. Refrence: H. Oya and T. Ono, A new altimeter for Mars land shape observations utilizing the ionospheric sounder system onboard the Planet-B spacecraft, Earth Planets Space, Vol. 50, pp.229-234, 1998 T. Kobayashi, H. Oya, and T. Ono, A-scope analysis of subsurface radar sounding of lunar mare region, Earth Planets Space, Vol. 54, pp.973-982, 2002

  15. Climate change effects on Glacier recession in Himalayas using Multitemporal SAR data and Automatic Weather Station observations

    NASA Astrophysics Data System (ADS)

    Kumar, V.; Singh, S. K.; Venkataraman, G.

    2009-04-01

    The Himalaya is the highest but the youngest mountain belt (20 to 60 million years B.P.) of the earth running in arc shape for about 2500 km. It has more than 90 peaks above 6000 m and contains about 50% of all glaciers outside of the polar environments (Bahadur, 1993). All glaciers in this region are in general recession since last 150 years (Paul et al.,1979). Gangotri, Siachen, Bara Shigri and Patsio are major glaciers in this region which are showing retreat with different rates and their respective tributary glaciers are completely disconnected from main body of glaciers. Spaceborne synthetic aperture radar data provide an important tool for monitoring the fluctuation of the glaciers. In this paper attempt has been made for quantifying the glacier retreat using multitemporal synthetic aperture radar (SAR) data. SAR intensity and phase information will be exploited separately under SAR intensity tracking and interferometric SAR (InSAR) coherence tracking (Strozzi et al., 2002) respectively. Glacier retreat study have been done using time series coregistered multi temporal SAR images. Simultaneously InSAR coherence thresholding is applied for tracking the snout of Gangotri glacier. It is observed that glacier is retreating at the rate of 21 m/a. Availability of high resolution spotlight mode TerraSAR-X SAR data will supplement the ENVISAT ASAR and ERS-1/2 based observations. The observatory in the proximity of Gangotri glacier has been made functional at Bhojbasa and all weather parameters viz. Snow fall, temperature, pressure, air vector, column water vapor and humidity are recorded twice a day as per WMO standards manually and automatically. Three Automatic Weather Stations (AWS) have been established in the glacier area at Bhojbasa , Kalindipass and Nandaban. Since Himalayan environment is presently under great stress of decay and degeneration, AWS data will be analyzed in the context of climate change effects on fluctuation of glaciers. References 1.Jagdish

  16. Field observations, experiments, and modeling of sediment production from freeze and thaw action on a bare, weathered granite slope in a temperate region of Japan

    NASA Astrophysics Data System (ADS)

    Tsutsumi, Daizo; Fujita, Masaharu

    2016-08-01

    In the present study, field observations and model simulations were conducted to examine the process of sediment production due to freeze and thaw action in a temperate climate region. Two small areas were designated and observations were conducted to determine the mechanisms of sediment production due to freeze and thaw action on a bare, weathered granite slope in the Tanakami Mountains in the southern part of Shiga Prefecture, Japan. During the cold season from 2004 to 2005, air, surface, and subsurface temperatures were measured at 10-min intervals. The sediment produced on plot 1 was collected and weighed once per week, whereas the sediment produced on plot 2 was left untouched until the end of the cold season. The freeze and thaw cycle occurred repeatedly, with the frozen zone (i.e., temperature < 0 °C) extending to a depth of 10 cm. Sediment was produced as a result of active freeze and thaw processes and, accordingly, there was no longer sediment production at the end of the cold season. Plots 1 and 2 produced 108 and 44 kg m- 2 year- 1 of sediment, respectively. This difference indicates that sediment cover of the saprolite surface mitigated the destructive effects of freezing. During the cold season from 2005 to 2006, a half of plot 1 was covered by broadleaves (Quercus serrata) and the other half was covered by coniferous leaves (Pinus densiflora); plot 2 was covered by no leaves to understand the effects of surface cover on the reduction in sediment production. The results showed that surface leaf cover dramatically decreased sediment production due to freeze and thaw action versus the no-surface cover. A simulation model combining a thermal conductivity analysis and a simple and empirical sediment production model was developed to estimate the amount of sediment produced by the freeze and thaw action. The observation results of temperature change and amount of sediment during the first season, from 2004 to 2005, were simulated with the model. The model

  17. Observation of Fermi arc surface states in a topological metal.

    PubMed

    Xu, Su-Yang; Liu, Chang; Kushwaha, Satya K; Sankar, Raman; Krizan, Jason W; Belopolski, Ilya; Neupane, Madhab; Bian, Guang; Alidoust, Nasser; Chang, Tay-Rong; Jeng, Horng-Tay; Huang, Cheng-Yi; Tsai, Wei-Feng; Lin, Hsin; Shibayev, Pavel P; Chou, Fang-Cheng; Cava, Robert J; Hasan, M Zahid

    2015-01-16

    The topology of the electronic structure of a crystal is manifested in its surface states. Recently, a distinct topological state has been proposed in metals or semimetals whose spin-orbit band structure features three-dimensional Dirac quasiparticles. We used angle-resolved photoemission spectroscopy to experimentally observe a pair of spin-polarized Fermi arc surface states on the surface of the Dirac semimetal Na3Bi at its native chemical potential. Our systematic results collectively identify a topological phase in a gapless material. The observed Fermi arc surface states open research frontiers in fundamental physics and possibly in spintronics. PMID:25593189

  18. Weather Watch

    ERIC Educational Resources Information Center

    Bratt, Herschell Marvin

    1973-01-01

    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)

  19. Evaluation of Nimbus 7 SMMR sensor with airborne radiometers and surface observations in the Norwegian Sea

    NASA Technical Reports Server (NTRS)

    Gloersen, P.; Cavalieri, D.; Crawford, J.; Campbell, W. J.; Farrelly, B.; Johannessen, J.; Johannessen, O. M.; Svendsen, E.; Kloster, K.

    1981-01-01

    Measurements made by the Nimbus 7 SMMR are compared with near simultaneous observations using the airborne SMMR simulator and with surface observations. The area of the test is in the Norwegian Sea between Bear Island and Northern Norway. It is noted that during the observation period two low-pressure systems were located in the test area, giving a spatial wind variation from 3-20 m/s. It is shown that the use of the currently available brightness temperatures and algorithms for SMMR does not give universally satisfactory results for SST and wind speed under extreme weather conditions. In addition, the SMMR simulator results are seen as indicating the need for more work on calibration.

  20. Understanding the coupled surface energy flux-valley wind system using observations in an alpine valley

    NASA Astrophysics Data System (ADS)

    Daniels, M. H.; Pardyjak, E.; Brutsaert, W. H.; Mage, R.; Parlange, M. B.

    2010-12-01

    Buoyancy-driven diurnal valley winds depend on relative partitioning of incoming solar radiation into the sensible and latent heat fluxes. Evaporation and transpiration at the surface contribute to the latent heat flux, while heating of the air near the surface results from the sensible heat flux. Thus if more moisture is available at the surface, (e.g. as soil moisture or dew) then more energy will be partitioned into the latent heat flux, and less will be available for the sensible heat flux. Presented here is an analysis of observations from surface weather stations placed throughout the La Fouly catchment (~20 km^2) in southern Switzerland during the summers of 2009 and 2010. The stations were equipped with sensors to measure atmospheric and land surface variables including: incoming solar radiation, 2 m air temperature, skin temperature, wind speed and direction, relative humidity, precipitation, soil moisture, and soil temperature. Scaling analysis is used to show how the balance between sensible and latent heat fluxes influences the buoyancy-driven valley winds. A preliminary analysis indicates that increased surface soil moisture tends to decrease the strength of slope winds both during the day and at night, while decreased soil moisture has the opposite effect. While this type of relation has been previously investigated through numerical simulations of valley or slope flows, it has not (to the authors' knowledge), been previously observed in the field.

  1. Solar Flares, CMEs, and Space Weather Measurements from the Surface of Mars with the RAD Instrument on the Mars Science Laboratory

    NASA Astrophysics Data System (ADS)

    Hassler, Donald M.; Zeitlin, Cary; Ehresmann, Bent; Wimmer-Schweingruber, Robert F.

    2015-08-01

    The Radiation Assessment Detector (RAD) is a compact, lightweight energetic particle analyzer currently operating on the surface of Mars as part of the Mars Science Laboratory (MSL) Mission. RAD is providing the first measurements of the energetic particle radiation environment on the surface of another planet due to solar flares, coronal mass ejections (CMEs), and galactic cosmic rays (GCRs).RAD is providing synoptic measurements of the energetic particle environment at a 2nd location in heliosphere (other than near-Earth or L1), and will aid heliospheric modeling over solar cycle. These observations of SEP fluxes are contributing to a solar energetic particle (SEP) event database at Mars and the Martian surface to aid prediction of Solar Particle Events (SPEs), including onset, temporal & size predictions.This presentation will provide an overview of the RAD investigation and present measurements of the solar flare, GCR and radiation environment on the surface of Mars, and discuss the importance of providing broad heliospheric coverage for situational awareness of space weather as we plan to send humans out into deep space and to Mars.RAD is supported by NASA (HEOMD) under JPL subcontract #1273039 to SwRI, and by DLR in Germany under contract with Christian-Albrechts-Universitat (CAU).

  2. Weather service upgrade too costly?

    NASA Astrophysics Data System (ADS)

    Bush, Susan

    America needs timely and accurate weather forecasting, said Ernest F. Hollings (D-S.C.), chairman of the Senate Committee on Commerce, Science, and Transportation on National Ocean Policy. Calling the existing warning and forecast system dangerously obsolete, Hollings said that new technology “should dramatically improve the accuracy and timeliness of weather predictions,” as we face the new challenge of bringing the National Weather Service into the 21st century. Hollings' committee heard testimony to consider the modernization of the NWS and pending legislation (S98, S916) on June 18.Major components of the Weather Service Modernization program, according to John A. Knauss, administrator of the National Oceanic and Atmospheric Administration, are the Next Generation Weather Radar (NEXRAD), a new generation of Geostationary Operational Environmental Satellites (GOES-NEXT), the Automated Surface Observing System (ASOS), and the Advanced Weather Interactive Processing System (AWIA). The best defense against severe weather—early warnings—is probably hampered by outdated equipment, he added.

  3. NPP VIIRS Land Surface Temperature EDR validation using NOAA's observation networks

    NASA Astrophysics Data System (ADS)

    Guillevic, P. C.; Privette, J. L.

    2012-12-01

    NOAA will soon use the new Visible Infrared Imager Radiometer Suite (VIIRS) on the Joint Polar Satellite System (JPSS) as its primary polar-orbiting satellite imager. Employing a near real-time processing system, NOAA will generate a series of Environmental Data Records (EDRs) from VIIRS data. For example, the VIIRS Land Surface Temperature (LST) EDR will estimate the surface skin temperature over all global land areas and provide key information for monitoring Earth surface energy and water fluxes. Because both VIIRS and its processing algorithms are new, NOAA is conducting a rigorous calibration and validation program to understand and improve product quality. This work presents a new validation methodology to estimate the quantitative uncertainty in the LST EDR, and contribute to improving the retrieval algorithm. It employs a physically-based approach to scaling up point LST measurements currently made operationally at many field and weather stations around the world. The scaling method consists of the merging information collected at different spatial resolutions within a land surface model to fully characterize large area (km x km scale) satellite products. The approach can be used to explore scaling issues over terrestrial surfaces spanning a large range of climate regimes and land cover types, including forests and mixed vegetated areas. First results show that VIIRS and MODIS (collection 5) LST products are very consistent. Over vegetated areas, VIIRS LST EDRs verify JPSS program quality requirements - bias and precision specifications of VIIRS LST EDRs are 1.5K and 2.5K. However, VIIRS agrees better with scaled-up field data than with non-scaled field observations. Over desert areas, current VIIRS LST EDRs do not verify JPSS specifications. VIIRS and MODIS LST products tend to underestimate surface temperature at night. Ultimately, this validation approach should lead to an accurate and continuously-assessed VIIRS LST products suitable to support weather

  4. Space weathering of near-Earth and main belt silicate-rich asteroids: observations and ion irradiation experiments

    NASA Astrophysics Data System (ADS)

    Marchi, S.; Brunetto, R.; Magrin, S.; Lazzarin, M.; Gandolfi, D.

    2005-12-01

    In this paper we report the results of a comparison between ion irradiation experiments (N^+, Ar^+, Ar++) on silicates, a large spectral data set of silicate-rich (S-type) asteroids, and ordinary chondrite meteorites (OCs). Ion irradiation experiments - conducted on Fe-poor olivine, Fe-poor orthopyroxene, bulk silicate-rich rocks and one OC - have been monitored by means of reflectance spectroscopy (0.3-2.5 μm). All these experiments produce reddening and darkening of reflectance spectra. The observational data consist of a set of visible and near-infrared (0.4-2.4 μm) spectra of S-type asteroids, that belong to main belt (MBAs) and near-Earth (NEOs) populations. By analyzing the spectra of OCs, MBAs, and NEOs, we find a similar mineralogy between most asteroids and meteorites, but different distributions of spectral slopes. We interpret these findings in the frame of space weathering induced by solar wind ion irradiation.

  5. Spectroscopic analyses of Fe and water in clays: A Martian surface weathering study

    NASA Technical Reports Server (NTRS)

    Bishop, J. L.; Pieters, Carle M.; Edwards, J. O.; Coyne, L. M.; Chang, S.

    1991-01-01

    Martian surface morphology suggests the presence of liquid H2O on Mars in the past. Reflectance spectra of the Martian surface include features which correspond to the crystal field transitions of iron, as well as features supporting the presence of ice and minerals containing structural OH and surface water. Researchers initiated further spectroscopic studies of surface iron and water and structural OH in clays in order to determine what remotely obtained spectra can indicate about the presence of clays on Mars based on a clearer understanding of the factors influencing the spectral features. Current technology allows researchers to better correlate the low frequency fundamental stretching and bending vibrations of O-H bonds with the diagnostic near infrared overtone and combination bands used in mineral characterization and identification.

  6. Greenland surface albedo changes 1981-2012 from satellite observations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Significant melt over Greenland has been observed during the last several decades associated with extreme warming events over the northern Atlantic Ocean. An analysis of surface albedo change over Greenland is presented, using a 32-year consistent satellite albedo product from the Global Land Surfac...

  7. Correction of Sampling Errors in Ocean Surface Cross-Sectional Estimates from Nadir-Looking Weather Radar

    NASA Technical Reports Server (NTRS)

    Caylor, I. Jeff; Meneghini, R.; Miller, L. S.; Heymsfield, G. M.

    1997-01-01

    The return from the ocean surface has a number of uses for airborne meteorological radar. The normalized surface cross section has been used for radar system calibration, estimation of surface winds, and in algorithms for estimating the path-integrated attenuation in rain. However, meteorological radars are normally optimized for observation of distributed targets that fill the resolution volume, and so a point target such as the surface can be poorly sampled, particularly at near-nadir look angles. Sampling the nadir surface return at an insufficient rate results in a negative bias of the estimated cross section. This error is found to be as large as 4 dB using observations from a high-altitude airborne radar. An algorithm for mitigating the error is developed that is based upon the shape of the surface echo and uses the returned signal at the three range gates nearest the peak surface echo.

  8. Controls over the thickness and elemental enrichment patterns in microscopic weathering-zones in exposed and terra-rossa covered carbonate bedrock surfaces

    NASA Astrophysics Data System (ADS)

    Ryb, U.; Erel, Y.; Matmon, A.

    2014-12-01

    Weathering zone's mineral and chemical compositions reflect the processes that govern denudation. We study 0-2500 μm thick weathering zones that evolve below carbonate bedrock surfaces, which experienced prolong denudation under Mediterranean climate, in the Judea Hills, Israel. Samples were collected from exposed (n=13) and terra-rossa covered (n=12) surfaces. In a previous study, denudation rates were calculated for the exposed bedrock samples. Since most of the terra-rossa volume is derived from an aeolian source, we do not consider it an integral part of the rock weathering zone. Bulk rock compositions range from limestone to dolomite, and frequently consist of a mixture of calcite and dolomite minerals. We analyzed major and trace elements across the weathering zones using a laser-ablation ICPMS system. Selected samples were further analyzed with an electron-probe. The extent of weathering zones is marked by the variation of element concentrations near the rock surface (relatively to the bulk rock), at depths of 0-500 μm and 0-2500 μm in exposed and terra-rossa covered surfaces, respectively. These zones are characterized by a relatively high porosity resulting from carbonate-mineral dissolution below the surface. Correlation analyses within each profile reveal three major elemental correlations: (1) Mg-Sr-U correlation results from variation in the abundance of the mineral dolomite. These elements are typically depleted toward the surface, due to preferential dissolution of dolomite crystals and precipitation of secondary calcite; (2) Al-Si correlation results from variations in the abundance of clay minerals, which may concentrate as an insoluble residue, or derive from the outer environment; and, (3) P-Y-REE correlation is highly enriched toward the surface, suggesting contribution from the outer environment. In contrast to silicate rocks, the extent and intensity of the weathering zones of exposed carbonate surfaces are decoupled from denudation rates

  9. Using Microwave Observations to Estimate Land Surface Temperature during Cloudy Conditions

    NASA Astrophysics Data System (ADS)

    Holmes, T. R.; Crow, W. T.; Hain, C.; Anderson, M. C.

    2014-12-01

    Land surface temperature (LST), a key ingredient for physically-based retrieval algorithms of hydrological states and fluxes, remains a poorly constrained parameter for global scale studies. The main two observational methods to remotely measure T are based on thermal infrared (TIR) observations and passive microwave observations (MW). TIR is the most commonly used approach and the method of choice to provide standard LST products for various satellite missions. MW-based LST retrievals on the other hand are not as widely adopted for land applications; currently their principle use is in soil moisture retrieval algorithms. MW and TIR technologies present two highly complementary and independent means of measuring LST. MW observations have a high tolerance to clouds but a low spatial resolution, and TIR has a high spatial resolution with temporal sampling restricted to clear skies. The nature of the temperature at the very surface layer of the land makes it difficult to combine temperature estimates between different methods. The skin temperature is characterized by a strong diurnal cycle that is dependant in timing and amplitude on the exact sensing depth and thermal properties of the vegetation. This paper builds on recent progress in characterizing the main structural components of the DTC that explain differences in TIR and MW estimates of LST. Spatial patterns in DTC timing (phase lag with solar noon) and DTC amplitude have been calculated for TIR, MW and compared to weather prediction estimates. Based on these comparisons MW LST can be matched to the TIR record. This paper will compare in situ measurements of LST with satellite estimates from (downscaled) TIR and (reconciled) MW products. By contrasting the validation results of clear sky days with those of cloudy days the expected tolerance to clouds of the MW observations will be tested. The goal of this study is to determine the weather conditions in which MW can supplement the TIR LST record.

  10. Modeling the dry-weather tidal cycling of fecal indicator bacteria in surface waters of an intertidal wetland.

    PubMed

    Sanders, Brett F; Arega, Feleke; Sutula, Martha

    2005-09-01

    Recreational water quality at beaches in California and elsewhere is often poor near the outlets of rivers, estuaries, and lagoons. This condition has prompted interest in the role of wetlands in modulating surface water concentrations of fecal indicator bacteria (FIB), the basis of water quality standards internationally. A model was developed and applied to predict the dry-weather tidal cycling of FIB in Talbert Marsh, an estuarine, intertidal wetland in Huntington Beach, California, in response to loads from urban runoff, bird feces, and resuspended sediments. The model predicts the advection, dispersion and die-off of total coliform, Escherichia coli, and enterococci using a depth-integrated formulation. We find that urban runoff and resuspension of contaminated wetland sediments are responsible for surface water concentrations of FIB in the wetland. Model predictions show that urban runoff controls surface water concentrations at inland sites and sediment resuspension controls surface water concentrations near the mouth. Direct wash-off of bird feces into the surface water is not a significant contributor, although bird feces can contribute to the sediment bacteria load. The key parameters needed to accurately predict FIB concentrations, using a validated hydrodynamic model, are: the load due to urban runoff, sediment erodibility parameters, and sediment concentrations and surface water die-off rates of enteric bacteria. In the present study, literature values for sediment erodibility and water column die-off rates are used and average concentrations of FIB are predicted within 1/2 log unit of measurements. Total coliform are predicted more accurately than E. coli or enterococci, both in terms of magnitude and tidal variability. Since wetland-dependent animals are natural sources of FIB, and FIB survive for long periods of time and may multiply in wetland sediments, these results highlight limitations of FIB as indicators of human fecal pollution in and near

  11. Aeolian weathering of Venusian surface materials - Preliminary results from laboratory simulations

    NASA Technical Reports Server (NTRS)

    Marshall, John R.; Greeley, Ronald; Tucker, David W.; Pollack, James B.

    1988-01-01

    An attempt is made to duplicate the atmospheric temperature, pressure, and approximate gas composition of all surface elevations on Venus by means of a simulator environment in which particles are impacted against rock targets as a way of studying planetary aeolian processes. While particles are abraded even at the low impact velocities envisioned for Venus, the same particles do not generate basaltic rock abrasion for impact velocities lower than 1 m/sec; comminution debris is instead transferred onto rock surfaces to form an accretion layer. These phenomena are seen as functions of the greater than 660 K temperatures encountered.

  12. An assessment of the Polar Weather Research and Forecasting (WRF) model representation of near-surface meteorological variables over West Antarctica

    NASA Astrophysics Data System (ADS)

    Deb, Pranab; Orr, Andrew; Hosking, J. Scott; Phillips, Tony; Turner, John; Bannister, Daniel; Pope, James O.; Colwell, Steve

    2016-02-01

    Despite the recent significant climatic changes observed over West Antarctica, which include large warming in central West Antarctica and accelerated ice loss, adequate validation of regional simulations of meteorological variables are rare for this region. To address this gap, results from a recent version of the Polar Weather Research and Forecasting model (Polar WRF) covering West Antarctica at a high horizontal resolution of 5 km were validated against near-surface meteorological observations. The model employed physics options that included the Mellor-Yamada-Nakanishi-Niino boundary layer scheme, the WRF Single Moment 5-Class cloud microphysics scheme, the new version of the rapid radiative transfer model for both shortwave and longwave radiation, and the Noah land surface model. Our evaluation finds this model to be a useful tool for realistically capturing the near-surface meteorological conditions. It showed high skill in simulating surface pressure (correlation ≥0.97), good skill for wind speed with better correlation at inland sites (0.7-0.8) compared to coastal sites (0.3-0.6), generally good representation of strong wind events, and good skill for temperature in winter (correlation ≥0.8). The main shortcomings of this configuration of Polar WRF are an occasional failure to properly represent transient cyclones and their influence on coastal winds, an amplified diurnal temperature cycle in summer, and a general tendency to underestimate the wind speed at inland sites in summer. Additional sensitivity studies were performed to quantify the impact of the choice of boundary layer scheme and surface boundary conditions. It is shown that the model is most sensitive to the choice of boundary layer scheme, with the representation of the temperature diurnal cycle in summer significantly improved by selecting the Mellor-Yamada-Janjic boundary layer scheme. By contrast, the model results showed little sensitivity to whether the horizontal resolution was 5 or

  13. Severe Weather

    ERIC Educational Resources Information Center

    Forde, Evan B.

    2004-01-01

    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…

  14. Severe Weather

    ERIC Educational Resources Information Center

    Forde, Evan B.

    2004-01-01

    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,…

  15. Applications of Land Surface Temperature from Microwave Observations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Land surface temperature (LST) is a key input for physically-based retrieval algorithms of hydrological states and fluxes. Yet, it remains a poorly constrained parameter for global scale studies. The main two observational methods to remotely measure T are based on thermal infrared (TIR) observation...

  16. Shortwave surface radiation budget network for observing small-scale cloud inhomogeneity fields

    NASA Astrophysics Data System (ADS)

    Madhavan, B. L.; Kalisch, J.; Macke, A.

    2015-03-01

    As part of the High Definition Clouds and Precipitation for advancing Climate Prediction Observational Prototype Experiment (HOPE), a high spatial density network of 99 silicon photodiode pyranometers was set up around Jülich (10 km x 12 km area) from April to July 2013, to capture the variability in the radiation field at the surface induced by small-scale cloud inhomogeneity. Each of these autonomously operated pyranometer stations was equipped with weather sensors for simultaneous measurements of ambient air temperature and relative humidity. In this paper, we provide the details of this unique setup of the pyranometer network and the data analysis with initial quality screening procedure we adopted. We also present some exemplary cases consisting of the days with clear, broken cloudy and overcast skies to assess our spatio-temporal observations from the network, and validate their consistency with other collocated radiation measurements available during the HOPE period.

  17. RECONSTRUCTING CORONAL MASS EJECTIONS WITH COORDINATED IMAGING AND IN SITU OBSERVATIONS: GLOBAL STRUCTURE, KINEMATICS, AND IMPLICATIONS FOR SPACE WEATHER FORECASTING

    SciTech Connect

    Liu Ying; Luhmann, Janet G.; Lin, Robert P.; Bale, Stuart D.; Thernisien, Arnaud; Vourlidas, Angelos; Davies, Jackie A.

    2010-10-20

    We reconstruct the global structure and kinematics of coronal mass ejections (CMEs) using coordinated imaging and in situ observations from multiple vantage points. A forward modeling technique, which assumes a rope-like morphology for CMEs, is used to determine the global structure (including orientation and propagation direction) from coronagraph observations. We reconstruct the corresponding structure from in situ measurements at 1 AU with the Grad-Shafranov method, which gives the flux-rope orientation, cross section, and a rough knowledge of the propagation direction. CME kinematics (propagation direction and radial distance) during the transit from the Sun to 1 AU are studied with a geometric triangulation technique, which provides an unambiguous association between solar observations and in situ signatures; a track fitting approach is invoked when data are available from only one spacecraft. We show how the results obtained from imaging and in situ data can be compared by applying these methods to the 2007 November 14-16 and 2008 December 12 CMEs. This merged imaging and in situ study shows important consequences and implications for CME research as well as space weather forecasting: (1) CME propagation directions can be determined to a relatively good precision as shown by the consistency between different methods; (2) the geometric triangulation technique shows a promising capability to link solar observations with corresponding in situ signatures at 1 AU and to predict CME arrival at the Earth; (3) the flux rope within CMEs, which has the most hazardous southward magnetic field, cannot be imaged at large distances due to expansion; (4) the flux-rope orientation derived from in situ measurements at 1 AU may have a large deviation from that determined by coronagraph image modeling; and (5) we find, for the first time, that CMEs undergo a westward migration with respect to the Sun-Earth line at their acceleration phase, which we suggest is a universal

  18. Coupling fast all-season soil strength land surface model with weather research and forecasting model to assess low-level icing in complex terrain

    NASA Astrophysics Data System (ADS)

    Sines, Taleena R.

    Icing poses as a severe hazard to aircraft safety with financial resources and even human lives hanging in the balance when the decision to ground a flight must be made. When analyzing the effects of ice on aviation, a chief cause for danger is the disruption of smooth airflow, which increases the drag force on the aircraft therefore decreasing its ability to create lift. The Weather Research and Forecast (WRF) model Advanced Research WRF (WRF-ARW) is a collaboratively created, flexible model designed to run on distributed computing systems for a variety of applications including forecasting research, parameterization research, and real-time numerical weather prediction. Land-surface models, one of the physics options available in the WRF-ARW, output surface heat and moisture flux given radiation, precipitation, and surface properties such as soil type. The Fast All-Season Soil STrength (FASST) land-surface model was developed by the U.S. Army ERDC-CRREL in Hanover, New Hampshire. Designed to use both meteorological and terrain data, the model calculates heat and moisture within the surface layer as well as the exchange of these parameters between the soil, surface elements (such as snow and vegetation), and atmosphere. Focusing on the Presidential Mountain Range of New Hampshire under the NASA Experimental Program to Stimulate Competitive Research (EPSCoR) Icing Assessments in Cold and Alpine Environments project, one of the main goals is to create a customized, high resolution model to predict and assess ice accretion in complex terrain. The purpose of this research is to couple the FASST land-surface model with the WRF to improve icing forecasts in complex terrain. Coupling FASST with the WRF-ARW may improve icing forecasts because of its sophisticated approach to handling processes such as meltwater, freezing, thawing, and others that would affect the water and energy budget and in turn affect icing forecasts. Several transformations had to take place in order

  19. Site characterization summary report for dry weather surface water sampling upper East Fork Poplar Creek characterization area Oak Ridge Y-12 Plant, Oak Ridge, Tennessee

    SciTech Connect

    1996-08-01

    This report describes activities associated with conducting dry weather surface water sampling of Upper East Fork Poplar Creek (UEFPC) at the Oak Ridge Y-12 Plant, Oak Ridge, Tennessee. This activity is a portion of the work to be performed at UEFPC Operable Unit (OU) 1 [now known as the UEFPC Characterization Area (CA)], as described in the RCRA Facility Investigation Plan for Group 4 at the Oak- Ridge Y-12 Plant, Oak Ridge, Tennessee and in the Response to Comments and Recommendations on RCRA Facility Investigation Plan for Group 4 at the Oak Ridge Y-12 Plant, Oak Ridge, Tennessee, Volume 1, Operable Unit 1. Because these documents contained sensitive information, they were labeled as unclassified controlled nuclear information and as such are not readily available for public review. To address this issue the U.S. Department of Energy (DOE) published an unclassified, nonsensitive version of the initial plan, text and appendixes, of this Resource Conservation and Recovery Act (RCRA) Facility Investigation (RFI) Plan in early 1994. These documents describe a program for collecting four rounds of wet weather and dry weather surface water samples and one round of sediment samples from UEFPC. They provide the strategy for the overall sample collection program including dry weather sampling, wet weather sampling, and sediment sampling. Figure 1.1 is a schematic flowchart of the overall sampling strategy and other associated activities. A Quality Assurance Project Plan (QAPJP) was prepared to specifically address four rounds of dry weather surface water sampling and one round of sediment sampling. For a variety of reasons, sediment sampling has not been conducted and has been deferred to the UEFPC CA Remedial Investigation (RI), as has wet weather sampling.

  20. Natural Weathering Rates of Silicate Minerals

    NASA Astrophysics Data System (ADS)

    White, A. F.

    2003-12-01

    Silicates constitute more than 90% of the rocks exposed at Earth's land surface (Garrels and Mackenzie, 1971). Most primary minerals comprising these rocks are thermodynamically unstable at surface pressure/temperature conditions and are therefore susceptible to chemical weathering. Such weathering has long been of interest in the natural sciences. Hartt (1853) correctly attributed chemical weathering to "the efficacy of water containing carbonic acid in promoting the decomposition of igneous rocks." Antecedent to the recent interest in the role of vegetation on chemical weathering, Belt (1874) observed that the most intense weathering of rocks in tropical Nicaragua was confined to forested regions. He attributed this effect to "the percolation through rocks of rain water charged with a little acid from decomposing vegetation." Chamberlin (1899) proposed that the enhanced rates of chemical weathering associated with major mountain building episodes in Earth's history resulted in a drawdown of atmospheric CO2 that led to periods of global cooling. Many of the major characteristics of chemical weathering had been described when Merrill (1906) published the groundbreaking volume Rocks, Rock Weathering, and Soils.The major advances since that time, particularly during the last several decades, have centered on understanding the fundamental chemical, hydrologic, and biologic processes that control weathering and in establishing quantitative weathering rates. This research has been driven by the importance of chemical weathering to a number environmentally and economically important issues. Undoubtedly, the most significant aspect of chemical weathering is the breakdown of rocks to form soils, a process that makes life possible on the surface of the Earth. The availability of many soil macronutrients such as magnesium, calcium, potassium, and PO4 is directly related to the rate at which primary minerals weather. Often such nutrient balances are upset by anthropogenic

  1. Progress in Space Weather Modeling and Observations Needed to Improve the Operational NAIRAS Model Aircraft Radiation Exposure Predictions

    NASA Astrophysics Data System (ADS)

    Mertens, C. J.; Kress, B. T.; Wiltberger, M. J.; Tobiska, W.; Xu, X.

    2011-12-01

    The Nowcast of Atmospheric Ionizing Radiation for Aviation Safety (NAIRAS) is a prototype operational model for predicting commercial aircraft radiation exposure from galactic and solar cosmic rays. NAIRAS predictions are currently streaming live from the project's public website, and the exposure rate nowcast is also available on the SpaceWx smartphone app for iPhone, IPad, and Android. Cosmic rays are the primary source of human exposure to high linear energy transfer radiation at aircraft altitudes, which increases the risk of cancer and other adverse health effects. Thus, the NAIRAS model addresses an important national need with broad societal, public health and economic benefits. The processes responsible for the variability in the solar wind, interplanetary magnetic field, solar energetic particle spectrum, and the dynamical response of the magnetosphere to these space environment inputs, strongly influence the composition and energy distribution of the atmospheric ionizing radiation field. During the development of the NAIRAS model, new science questions were identified that must be addressed in order to obtain a more reliable and robust operational model of atmospheric radiation exposure. Addressing these science questions require improvements in both space weather modeling and observations. The focus of this talk is to present these science questions, the proposed methodologies for addressing these science questions, and the anticipated improvements to the operational predictions of atmospheric radiation exposure. The overarching goal of this work is to provide a decision support tool for the aviation industry that will enable an optimal balance to be achieved between minimizing health risks to passengers and aircrew while simultaneously minimizing costs to the airline companies.

  2. Surface Turbulent Fluxes Over Pack Ice Inferred from TOVS Observations

    NASA Technical Reports Server (NTRS)

    Lindsay, R. W.; Francis, J. A.; Persson, P. O. G.; Rothrock, D. A.; Schweiger, A. J.

    1996-01-01

    A one-dimensional, atmospheric boundary layer model is coupled to a thermodynamic ice model to estimate the surface turbulent fluxes over thick sea ice. The principal forcing parameters in this time-dependent model are the air temperature, humidity, and wind speed at a specified level (either at 2 m or at 850 mb) and the downwelling surface radiative fluxes. The free parameters. are the air temperature, humidity, and wind speed profiles below the specified level, the surface skin temperature, the ice temperature profile, and the surface turbulent fluxes. The goal is to determine how well we can estimate the turbulent surface heat and momentum fluxes using forcing parameters from atmospheric temperatures and radiative fluxes retrieved from the TIROS-N Operational Vertical Sounder (TOVS) data. Meteorological observations from the Lead Experiment (LeadEx, April 1992) ice camp are used to validate turbulent fluxes computed with the surface observations and the results are used to compare with estimates based on radio-sonde observations or with estimates based on TOVS data. We find that the TOVS-based estimates of the stress are significantly more accurate than those found with a constant geostrophic drag coefficient, with a root-mean-square error about half as large. This improvement is due to stratification effects included in the boundary layer model. The errors in the sensible heat flux estimates, however, are large compared to the small mean values observed during the field experiment.

  3. Space Weathering of Lunar Rocks

    NASA Technical Reports Server (NTRS)

    Noble, S. K.; Keller, L. P.; Christoffersen, R.; Rahman, Z.

    2012-01-01

    All materials exposed at the lunar surface undergo space weathering processes. On the Moon, boulders make up only a small percentage of the exposed surface, and areas where such rocks are exposed, like central peaks, are often among the least space weathered regions identified from remote sensing data. Yet space weathered surfaces (patina) are relatively common on returned rock samples, some of which directly sample the surface of larger boulders. Because, as witness plates to lunar space weathering, rocks and boulders experience longer exposure times compared to lunar soil grains, they allow us to develop a deeper perspective on the relative importance of various weathering processes as a function of time.

  4. Weather & Weather Maps. Teacher's Manual.

    ERIC Educational Resources Information Center

    Metro, Peter M.; Green, Rachel E.

    This guide is intended to provide an opportunity for students to work with weather symbols used for reporting weather. Also included are exercises in location of United States cities by latitude and longitude, measurement of distances in miles and kilometers, and prediction of weather associated with various types of weather fronts. (RE)

  5. SEM and TEM Observation of the Surfaces of the Fine-Grained Particles Retrieved from the Muses-C Regio on the Asteroid 25413 Itokawa

    NASA Technical Reports Server (NTRS)

    Noguchi, T.; Nakamura, T.; Zolensky, Michael E.; Tanaka, M.; Hashimoto, T.; Konno, M.; Nakato, A.; Ogami, T.; Fujimura, A.; Abe, M.; Yada, T.; Mukai, T.; Ueno, M.; Okada, T.; Shirai, K.; Ishibashi, Y.; Okazaki, R.

    2011-01-01

    Surface materials on airless solar system bodies exposed to interplanetary space are gradually changed their visible to near-infrared reflectance spectra by the process called "space weathering", which makes the spectra darker and redder. Hapke et al. proposed a model of space weathering: vapor deposition of nanophase reduced iron (npFe(sup 0)) on the surfaces of the grains within the very surface of lunar regolith. This model has been proved by detailed observation of the surfaces of the lunar soil grains by transmission electron microscope (TEM). They demonstrated that npFe(sup 0) was formed by a combination of vapor deposition and irradiation effects. In other words, both micrometeorite impacts and irradiation by solar wind and galactic cosmic ray play roles on the space weathering on the Moon. Because there is a continuum of reflectance spectra from those of Q-type asteroids (almost the same as those of ordinary chondrites) to those of S-type asteroids, it is strongly suggested that reflectance spectra of asteroids composed of ordinary chondrite-like materials were modified over time to those of S-type asteroids due to space weathering. It is predicted that a small amount of npFe(sup 0) on the surface of grains in the asteroidal regolith composed of ordinary chondrite-like materials is the main agent of asteroidal space weathering.

  6. An observational correlation between stellar brightness variations and surface gravity.

    PubMed

    Bastien, Fabienne A; Stassun, Keivan G; Basri, Gibor; Pepper, Joshua

    2013-08-22

    Surface gravity is a basic stellar property, but it is difficult to measure accurately, with typical uncertainties of 25 to 50 per cent if measured spectroscopically and 90 to 150 per cent if measured photometrically. Asteroseismology measures gravity with an uncertainty of about 2 per cent but is restricted to relatively small samples of bright stars, most of which are giants. The availability of high-precision measurements of brightness variations for more than 150,000 stars provides an opportunity to investigate whether the variations can be used to determine surface gravities. The Fourier power of granulation on a star's surface correlates physically with surface gravity: if brightness variations on timescales of hours arise from granulation, then such variations should correlate with surface gravity. Here we report an analysis of archival data that reveals an observational correlation between surface gravity and root mean squared brightness variations on timescales of less than eight hours for stars with temperatures of 4,500 to 6,750 kelvin, log surface gravities of 2.5 to 4.5 (cgs units) and overall brightness variations of less than three parts per thousand. A straightforward observation of optical brightness variations therefore allows a determination of the surface gravity with a precision of better than 25 per cent for inactive Sun-like stars at main-sequence to giant stages of evolution. PMID:23969460

  7. COSMO-SkyMed measurements in precipitation over the sea: analysis of Louisiana summer thunderstorms by simultaneous weather radar observations

    NASA Astrophysics Data System (ADS)

    Roberto, N.; Baldini, L.; Gorgucci, E.; Facheris, L.; Chandrasekar, V.

    2012-04-01

    Radar signatures of rain cells are investigated using X-band synthetic aperture radar (X-SAR) images acquired from COSMO-SkyMed constellation over oceans off the coast of Louisiana in summer 2010 provided by ASI archive. COSMO-SkyMed (CSK) monitoring of Deepwater Horizon oil spill provided a big amount of data during the period April-September 2010 and in July-August when several thunderstorms occurred in that area. In X-SAR images, radar signatures of rain cells over the sea usually consist of irregularly shaped bright and dark patches. These signatures originate from 1) the scattering and attenuation of radiation by hydrometers in the rain cells and 2) the modification of the sea roughness induced by the impact of raindrops and by wind gusts associated with rain cell. However, the interpretation of precipitation signatures in X-SAR images is not completely straightforward, especially over sea. Coincident measurements from ground based radars and an electromagnetic (EM) model predicting radar returns from the sea surface corrugated by rainfall are used to support the analysis. A dataset consisting of 4 CSK images has been collected over Gulf of Mexico while a WSR-88D NEXRAD S-band Doppler radar (KLIX) located in New Orleans was scanning the nearby portion of ocean. Terrestrial measurements have been used to reconstruct the component of X-SAR returns due to precipitation by modifying the known technique applied on measurements over land (Fritz et al. 2010, Baldini et al. 2011). Results confirm that the attenuation signature in X-SAR images collected over land, particularly pronounced in the presence of heavy precipitation cells, can be related to the S-band radar reflectivity integrated along the same path. The Normalized Radar Cross Section (NRCS) of land is considered to vary usually up to a few dBs in case of rain but with strong dependency on the specific type and conditions of land cover. While the NRCS of sea surface in clear weather condition can be

  8. Estimating long-term surface hydrological components by coupling remote sensing observation with surface flux model.

    SciTech Connect

    Song, J.; Wesely, M. L.

    2002-05-02

    A model framework for parameterized subgrid-scale surface fluxes (PASS) has been applied to use satellite data, models, and routine surface observations to infer root-zone available moisture content and evapotranspiration rate with moderate spatial resolution within Walnut River Watershed in Kansas. Biweekly composite normalized difference vegetative index (NDVI) data are derived from observations by National Oceanic and Atmospheric Administration (NOAA) satellites. Local surface observations provide data on downwelling solar irradiance, air temperature, relative humidity, and wind speed. Surface parameters including roughness length, albedo, surface water conductance, and the ratio of soil heat flux to net radiation are estimated; pixel-specific near-surface meteorological conditions such as air temperature, vapor pressure, and wind speed are adjusted according to local surface forcing. The PASS modeling system makes effective use of satellite data and can be run for large areas for which flux data do not exist and surface meteorological data are available from only a limited number of ground stations. The long-term surface hydrological budget is evaluated using radar-derived precipitation estimates, surface meteorological observations, and satellite data. The modeled hydrological components in the Walnut River Watershed compare well with stream gauge data and observed surface fluxes during 1999.

  9. RAPID COMMUNICATION: Observation of a dynamic specular weld pool surface

    NASA Astrophysics Data System (ADS)

    Zhang, Y. M.; Song, H. S.; Saeed, G.

    2006-06-01

    Observation and measurement of a weld pool surface is a key towards the development of next generation intelligent welding machines which can mimic a skilled human welder to a certain extent. However, the bright arc radiation and the specular surface complicate the observation and measurement task. This paper proposes a novel method to turn the difficulty of the specular surface into an advantage by exploiting the difference between propagation of an illumination laser and the arc plasma. The governing law is simply the reflection law which can provide the base for the computation of the weld pool surface. Experimental results verified the effectiveness of the proposed method in acquiring clear images in the presence of the bright arc.

  10. Use of weather research and forecasting model outputs to obtain near-surface refractive index structure constant over the ocean.

    PubMed

    Qing, Chun; Wu, Xiaoqing; Li, Xuebin; Zhu, Wenyue; Qiao, Chunhong; Rao, Ruizhong; Mei, Haipin

    2016-06-13

    The methods to obtain atmospheric refractive index structure constant (Cn2) by instrument measurement are limited spatially and temporally and they are more difficult and expensive over the ocean. It is useful to forecast Cn2 effectively from Weather Research and Forecasting Model (WRF) outputs. This paper introduces a method that WRF Model is used to forecast the routine meteorological parameters firstly, and then Cn2 is calculated based on these parameters by the Bulk model from the Monin-Obukhov similarity theory (MOST) over the ocean near-surface. The corresponding Cn2 values measured by the micro-thermometer which is placed on the ship are compared with the ones forecasted by WRF model to determine how this method performs. The result shows that the forecasted Cn2 is consistent with the measured Cn2 in trend and the order of magnitude as a whole, as well as the correlation coefficient is up to 77.57%. This method can forecast some essential aspects of Cn2 and almost always captures the correct magnitude of Cn2, which experiences fluctuations of two orders of magnitude. Thus, it seems to be a feasible and meaningful method that using WRF model to forecast near-surface Cn2 value over the ocean. PMID:27410347

  11. An assessment of buoy-derived and numerical weather prediction surface heat fluxes in the tropical Pacific

    NASA Astrophysics Data System (ADS)

    Cronin, Meghan F.; Fairall, Christopher W.; McPhaden, Michael J.

    2006-06-01

    As part of the Eastern Pacific Investigation of Climate Processes program, from 2000 through 2003, the easternmost 95°W Tropical Atmosphere Ocean (TAO) moorings were enhanced to provide time series of net surface heat flux, and the National Oceanic and Atmospheric Administration ship maintaining the 95°W and 110°W TAO lines was enhanced to monitor surface heat fluxes and atmospheric boundary layer structure. In this study we compare the ship-based and buoy-based radiative, bulk latent, and sensible heat fluxes, as well as the meteorological state variables used to compute the turbulent heat fluxes. The buoy net surface heat flux measurements appear to have an overall uncertainty near the target 10 W m-2, when careful attention is paid to the state variables. When hourly averaged data were unavailable, the telemetered daily averaged data were used in combination with an estimate of the mesoscale gustiness. In the eastern tropical Pacific a warm layer correction to account for stratification above 1-m depth was important only during the warm season (January-May) near the equator. These high-quality, cross-validated buoy heat flux time series are then used to assess the National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR), NCEP/Department of Energy, and 40-year European Centre for Medium-Range Weather Forecasts reanalyses' surface heat fluxes. All reanalyses show that over warm water where deep convection is prominent, latent heat loss is too large and net solar radiation is too weak; conversely, in regions of stratocumulus over cool water, net solar radiation is too strong, and for NCEP/NCAR, latent heat loss is too weak.

  12. Observations of Heliospheric Faraday Rotation (FR) and Interplanetary Scintillation (IPS) with the LOw Frequency ARray (LOFAR): Steps Towards Improving Space-Weather Forecasting Capabilities

    NASA Astrophysics Data System (ADS)

    Bisi, M. M.; Fallows, R. A.; Sobey, C.; Eftekhari, T.; Jensen, E. A.; Jackson, B. V.; Yu, H. S.; Hick, P. P.; Odstrcil, D.; Tokumaru, M.

    2015-12-01

    The phenomenon of space weather - analogous to terrestrial weather which describes the changing pressure, temperature, wind, and humidity conditions on Earth - is essentially a description of the changes in velocity, density, magnetic field, high-energy particles, and radiation in the near-Earth space environment including the effects of such changes on the Earth's magnetosphere, radiation belts, ionosphere, and thermosphere. Space weather can be considered to have two main strands: (i) scientific research, and (ii) applications. The former is self-explanatory, but the latter covers operational aspects which includes its forecasting. Understanding and forecasting space weather in the near-Earth environment is vitally important to protecting our modern-day reliance (militarily and commercially) on satellites, global-communication and navigation networks, high-altitude air travel (radiation concerns particularly on polar routes), long-distance power/oil/gas lines and piping, and for any future human exploration of space to list but a few. Two ground-based radio-observing remote-sensing techniques that can aid our understanding and forecasting of heliospheric space weather are those of interplanetary scintillation (IPS) and heliospheric Faraday rotation (FR). The LOw Frequency ARray (LOFAR) is a next-generation 'software' radio telescope centered in The Netherlands with international stations spread across central and northwest Europe. For several years, scientific observations of IPS on LOFAR have been undertaken on a campaign basis and the experiment is now well developed. More recently, LOFAR has been used to attempt scientific heliospheric FR observations aimed at remotely sensing the magnetic field of the plasma traversing the inner heliosphere. We present our latest progress using these two radio heliospheric-imaging remote-sensing techniques including the use of three-dimensional (3-D) modeling and reconstruction techniques using other, additional data as input

  13. A scheme for computing surface layer turbulent fluxes from mean flow surface observations

    NASA Technical Reports Server (NTRS)

    Hoffert, M. I.; Storch, J.

    1978-01-01

    A physical model and computational scheme are developed for generating turbulent surface stress, sensible heat flux and humidity flux from mean velocity, temperature and humidity at some fixed height in the atmospheric surface layer, where conditions at this reference level are presumed known from observations or the evolving state of a numerical atmospheric circulation model. The method is based on coupling the Monin-Obukov surface layer similarity profiles which include buoyant stability effects on mean velocity, temperature and humidity to a force-restore formulation for the evolution of surface soil temperature to yield the local values of shear stress, heat flux and surface temperature. A self-contained formulation is presented including parameterizations for solar and infrared radiant fluxes at the surface. Additional parameters needed to implement the scheme are the thermal heat capacity of the soil per unit surface area, surface aerodynamic roughness, latitude, solar declination, surface albedo, surface emissivity and atmospheric transmissivity to solar radiation.

  14. Cassini ISS observations of Titan's surface and changes in its south-polar lakes

    NASA Astrophysics Data System (ADS)

    Turtle, Elizabeth; Perry, Jason; McEwen, Alfred; Hayes, Alexander; West, Robert

    Cassini's Imaging Science Subsystem (ISS) has been returning images of Titan since early 2004, continuing through the 65 close Titan encounters that have been performed to date. These ob-servations have been combined to produce a 938-nm albedo map of the surface with resolutions ranging from several kilometers to several hundred meters. The morphologies observed on Titan's surface reflect a wide variety of geological features [1]: roughly east-west streamlined shapes, suggestive of aeolian processes, consistent with Cassini RADAR observations of dunes at low latitudes [2]; narrow, curvilinear channels; dark lakes and seas at high latitudes [e.g., 3]; rare impact structures, further evidence for a geologically young surface; and possible tec-tonic and cryovolcanic structures. Changes have also been observed: a new large dark area appeared between July 2004 and June 2005 [3] and may have subsequently faded. Recent ISS observations of Ontario Lacus suggest that its shoreline may have receded as well [cf. 4]. Such changes are interpreted to be the result of precipitation and ponding of liquid methane and the subsequent infiltration into the subsurface or evaporation thereof [3]. No changes have been observed to date in the lakes and seas at high northern latitudes. We will present ISS' most recent map of Titan's surface, documenting changes that may have resulted from weather and seasonal changes and their implications for Titan's active methane cycle. References: [1] Porco et al. (2005) Nature 434, 159-168. [2] Lorenz et al. (2006) Science 312, 724-727. [3] Turtle et al. (2009) GRL 36, DOI 0.1029/2008GL036186. [4] Hayes et al. (2009) Eos Trans. AGU, 90, Abstract P54C-02.

  15. Direct observation of negative-index microwave surface waves.

    PubMed

    Dockrey, J A; Horsley, S A R; Hooper, I R; Sambles, J R; Hibbins, A P

    2016-01-01

    Waves propagating in a negative-index material have wave-front propagation (wavevector, k) opposite in direction to that of energy flow (Poynting vector, S). Here we present an experimental realisation at microwave frequencies of an analogous surface wave phenomenon whereby a metasurface supports a surface mode that has two possible wavevector eigenstates within a narrow band of frequencies: one that supports surface waves with positive mode index, and another that supports surface waves with negative mode index. Phase sensitive measurements of the near-field of surface waves across the metasurface show the contrasting spatial evolution of the two eigenstates, providing a unique opportunity to directly observe the negative-index phenomenon. PMID:26903284

  16. Direct observation of negative-index microwave surface waves

    NASA Astrophysics Data System (ADS)

    Dockrey, J. A.; Horsley, S. A. R.; Hooper, I. R.; Sambles, J. R.; Hibbins, A. P.

    2016-02-01

    Waves propagating in a negative-index material have wave-front propagation (wavevector, k) opposite in direction to that of energy flow (Poynting vector, S). Here we present an experimental realisation at microwave frequencies of an analogous surface wave phenomenon whereby a metasurface supports a surface mode that has two possible wavevector eigenstates within a narrow band of frequencies: one that supports surface waves with positive mode index, and another that supports surface waves with negative mode index. Phase sensitive measurements of the near-field of surface waves across the metasurface show the contrasting spatial evolution of the two eigenstates, providing a unique opportunity to directly observe the negative-index phenomenon.

  17. Direct observation of negative-index microwave surface waves

    PubMed Central

    Dockrey, J. A.; Horsley, S. A. R.; Hooper, I. R.; Sambles, J. R.; Hibbins, A. P.

    2016-01-01

    Waves propagating in a negative-index material have wave-front propagation (wavevector, k) opposite in direction to that of energy flow (Poynting vector, S). Here we present an experimental realisation at microwave frequencies of an analogous surface wave phenomenon whereby a metasurface supports a surface mode that has two possible wavevector eigenstates within a narrow band of frequencies: one that supports surface waves with positive mode index, and another that supports surface waves with negative mode index. Phase sensitive measurements of the near-field of surface waves across the metasurface show the contrasting spatial evolution of the two eigenstates, providing a unique opportunity to directly observe the negative-index phenomenon. PMID:26903284

  18. Observation of Surface Layering in a Nonmetallic Liquid

    SciTech Connect

    Mo,H.; Evmenenko, G.; Kewalramani, S.; Kim, K.; Ehrlich, S.; Dutta, P.

    2006-01-01

    Oscillatory density profiles (layers) have previously been observed at the free surfaces of liquid metals but not in other isotropic liquids. We have used x-ray reflectivity to study a molecular liquid, tetrakis(2-ethylhexoxy)silane. When cooled to T/T{sub c}{approx}0.25 (well above the freezing point for this liquid), density oscillations appear at the surface. Lateral order within the layers is liquidlike. Our results confirm theoretical predictions that a surface-layered state will appear even in dielectric liquids at sufficiently low temperatures, if not preempted by freezing.

  19. Weather and climate

    NASA Technical Reports Server (NTRS)

    1975-01-01

    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.

  20. Observations During GRIP from HIRAD: Ocean Surface Wind Speed and Rain Rate

    NASA Technical Reports Server (NTRS)

    Miller, Timothy L.; James, M. W.; Jones, L.; Ruf, C. S.; Uhlhorn, E. W.; Bailey, M. C.; Buckley, C. D.; Simmons, D. E.; Johnstone, S.; Peterson, A.; Schultz, L. A.; Biewas, S.; Johnson, J. W.; Shah, G.; Feingstein, D.; Cleveland, W. H.; Johnson, J.; Hood, R. E.

    2011-01-01

    HIRAD (Hurricane Imaging Radiometer) flew on the WB-57 during NASA's GRIP (Genesis and Rapid Intensification Processes) campaign in August - September of 2010. HIRAD is a new C-band radiometer using a synthetic thinned array radiometer (STAR) technology to obtain cross-track resolution of approximately 3 degrees, out to approximately 60 degrees to each side of nadir. By obtaining measurements of emissions at 4, 5, 6, and 6.6 GHz, observations of ocean surface wind speed and rain rate can be inferred. This technique has been used for many years by precursor instruments, including the Stepped Frequency Microwave Radiometer (SFMR), which has been flying on the NOAA and USAF hurricane reconnaissance aircraft for several years. The advantage of HIRAD over SFMR is that HIRAD can observe a +/- 60-degree swath, rather than a single footprint at nadir angle. Results from the flights during the GRIP campaign will be shown, including images of brightness temperatures, wind speed, and rain rate. To the extent possible, comparisons will be made with observations from other instruments on the GRIP campaign, for which HIRAD observations are either directly comparable or are complementary. Potential impacts on operational ocean surface wind analyses and on numerical weather forecasts will also be discussed.

  1. Land Surface Microwave Emissivity Dynamics: Observations, Analysis and Modeling

    NASA Technical Reports Server (NTRS)

    Tian, Yudong; Peters-Lidard, Christa D.; Harrison, Kenneth W.; Kumar, Sujay; Ringerud, Sarah

    2014-01-01

    Land surface microwave emissivity affects remote sensing of both the atmosphere and the land surface. The dynamical behavior of microwave emissivity over a very diverse sample of land surface types is studied. With seven years of satellite measurements from AMSR-E, we identified various dynamical regimes of the land surface emission. In addition, we used two radiative transfer models (RTMs), the Community Radiative Transfer Model (CRTM) and the Community Microwave Emission Modeling Platform (CMEM), to simulate land surface emissivity dynamics. With both CRTM and CMEM coupled to NASA's Land Information System, global-scale land surface microwave emissivities were simulated for five years, and evaluated against AMSR-E observations. It is found that both models have successes and failures over various types of land surfaces. Among them, the desert shows the most consistent underestimates (by approx. 70-80%), due to limitations of the physical models used, and requires a revision in both systems. Other snow-free surface types exhibit various degrees of success and it is expected that parameter tuning can improve their performances.

  2. Using Three-Dimensional Passive Seismic Imaging to Capture Near-Surface Weathering and Its Influence on Overlying Vegetation

    NASA Astrophysics Data System (ADS)

    Taylor, N. J.; Dueker, K. G.; Riebe, C. S.; Chen, P.; Flinchum, B. A.; Holbrook, W. S.

    2015-12-01

    In mountain landscapes, vegetation is tightly coupled to elevation through orographic effects on temperature and precipitation. However, at any given elevation, vegetation can vary markedly due to non-climatic factors such as lithology. For example, tree-canopy cover correlates strongly with bedrock composition in the Sierra Nevada, California, via mechanisms that remain poorly understood. We are exploring the hypothesis that vegetation varies across bedrock types in the Sierra Nevada due to differences in near-surface fracture density that influence the availability of water for plants. Our approach uses data collected from autonomous seismic nodes that record seismic energy generated by ambient sources such as wind, rivers, and road traffic. By deploying the nodes across the landscape in arrays spanning 200 m on a side, we can obtain a three-dimensional image of spatial variations in near-surface weathering. Data presented here will be derived from arrays deployed for 3 days each spanning an area of 0.04 km2 at each of three sites underlain by Sierra Nevada granites and granodiorites. To isolate the effects of lithology on vegetation, we chose sites that span a range of forest cover and mafic-mineral content but have similar microclimate (i.e., with similar aspect and elevation). Our data will provide a three-dimensional model of P- and S-wave velocity structure, which we can invert using a Hertz-Mindlin porosity model to constrain the thickness and degree of fracturing and thus the subsurface water-holding potential for plants. We will explore the hypothesis that the densest vegetation occurs within bedrock with the densest fracturing, due to enhanced availability of water in the near surface. We will present a comparison of our results from the Sierra Nevada and results from similar experiments at the Snowy Range and Blair Wallis field sites of the Wyoming Center for Environmental Hydrology and Geophysics.

  3. Observational & modeling analysis of surface heat and moisture fluxes

    SciTech Connect

    Smith, E.

    1995-09-01

    An observational and modeling study was conducted to help assess how well current GCMs are predicting surface fluxes under the highly variable cloudiness and flow conditions characteristic of the real atmosphere. The observational data base for the study was obtained from a network of surface flux stations operated during the First ISLSCP Field Experiment (FIFE). The study included examination of a surface-driven secondary circulation in the boundary layer resulting from a persistent cross-site gradient in soil moisture, to demonstrate the sensitivity of boundary layer dynamics to heterogeneous surface fluxes, The performance of a biosphere model in reproducing the measured surface fluxes was evaluated with and without the use of satellite retrieval of three key canopy variables with RMS uncertainties commensurate with those of the measurements themselves. Four sensible heat flux closure schemes currently being used in GCMs were then evaluated against the FIFE observations. Results indicate that the methods by which closure models are calibrated lead to exceedingly large errors when the schemes are applied to variable boundary layer conditions. 4 refs., 2 figs.

  4. Emergent relation between surface vapor conductance and relative humidity profiles yields evaporation rates from weather data

    PubMed Central

    Salvucci, Guido D.; Gentine, Pierre

    2013-01-01

    The ability to predict terrestrial evapotranspiration (E) is limited by the complexity of rate-limiting pathways as water moves through the soil, vegetation (roots, xylem, stomata), canopy air space, and the atmospheric boundary layer. The impossibility of specifying the numerous parameters required to model this process in full spatial detail has necessitated spatially upscaled models that depend on effective parameters such as the surface vapor conductance (Csurf). Csurf accounts for the biophysical and hydrological effects on diffusion through the soil and vegetation substrate. This approach, however, requires either site-specific calibration of Csurf to measured E, or further parameterization based on metrics such as leaf area, senescence state, stomatal conductance, soil texture, soil moisture, and water table depth. Here, we show that this key, rate-limiting, parameter can be estimated from an emergent relationship between the diurnal cycle of the relative humidity profile and E. The relation is that the vertical variance of the relative humidity profile is less than would occur for increased or decreased evaporation rates, suggesting that land–atmosphere feedback processes minimize this variance. It is found to hold over a wide range of climate conditions (arid–humid) and limiting factors (soil moisture, leaf area, energy). With this relation, estimates of E and Csurf can be obtained globally from widely available meteorological measurements, many of which have been archived since the early 1900s. In conjunction with precipitation and stream flow, long-term E estimates provide insights and empirical constraints on projected accelerations of the hydrologic cycle. PMID:23576717

  5. Correlating CCM upper atmosphere parameters to surface observations for regional climate change predictions

    SciTech Connect

    Li, Xiangshang; Sailor, D.J.

    1997-11-01

    This paper explores the use of statistical downscaling of General Circulation Model (GCM) results for the purpose of regional climate change analysis. The strong correlation between surface observations and GCM upper air predictions is used in an approach very similar to the Model Output Statistics approach used in numerical weather prediction. The primary assumption in this analysis is that the statistical relationships remain unchanged under conditions of climatic change. These relations are applied to GCM upper atmosphere predictions for future (2*CO{sub 2}) climate predictions. The result is a set of regional climate change predictions conceptually valid at the scale of cities. The downscaling for specific cities within a GCM grid cell reveals some of the anticipated variability within the grid cell. In addition, multiple linear regression analysis may indicate warming that is significantly higher or lower for a particular region than the raw data from the GCM runs. 3 refs., 3 figs., 2 tabs.

  6. Further investigations of automated surface observing system (ASOS) winds used in air quality modeling applications

    SciTech Connect

    Brower, R.P.; Jones, W.B.; Sherwell, J.

    1999-07-01

    Since 1992, a significant shift in the way standard surface meteorological data are observed and collected has occurred across the country. The National Weather Service, the Federal Aviation Administration, and the Department of Defense have been deploying the Automated Surface Observing System (ASOS) at nearly one thousand sites. Prior to ASOS, manual observation and recordation were the norm. With the advent of ASOS, an unprecedented level of meteorological data is now available; observations of standard meteorological variables are available almost real-time at more sites. However, with ASOS, meteorological data are being gathered in a fundamentally different way. New automated instruments sample, analyze, and record meteorological observations without human intervention. Many of these meteorological observations are key inputs to predictive air quality models. Reliable estimates of plume transport and dispersion require reliable and available meteorological data. The effect of the ASOS method of data collection on the dispersion modeling community is not clear. Because the hourly data now being reported at most stations across the country are being gathered in a fundamentally different way than previously, it is prudent to examine the differences between hourly meteorological observations gathered before and after ASOS. A preliminary analysis1 of pre-ASOS and ASOS data suggested that the differences in the observations could impact the data's application to air quality models. This expanded study examines more thoroughly the differences between wind data gathered before and after ASOS implementation in order to identify potential ramifications for air quality modeling. Pre-ASOS and ASOS data, from five stations in and around Maryland that represent the diversity of urbanization and topography of the region and that have a reasonably long record of ASOS observations, are examined.

  7. Surface heat budget at the Nordic Seas in Lagrangian observations

    NASA Astrophysics Data System (ADS)

    de La Lama, Marta S.; Isachsen, Pål E.; Koszalka, Inga; Lacasce, Joseph H.

    2014-05-01

    In the Nordic Seas, the warm, inflowing Atlantic Water is cooled until it is dense enough to sink. Thereafter it circulates at depth, eventually feeding the North Atlantic Deep Water. The air-sea interaction which facilitates this cooling is a complex process involving diverse phenomena, from surface heating to turbulent entrainment at the base of the ocean surface mixed layer. In the present study, we use 486 freely-drifting surface buoys to observe temperature changes on water parcels and the response to air-sea heat fluxes. Such Lagrangian observations advantageously 'filter out' horizontal heat fluxes, since the buoys are advected by the flow, allowing one to focus on the vertical exchanges. We examine the temporal evolution of temperature on the drifters and the correlations with surface heat fluxes, obtained from ECMWF ERA-Interim reanalyses. The frequency spectra indicate a clear ω-2 dependence at frequencies higher than roughly 1/40 days-1. The temperature fluctuations on the other hand are correlated with surface fluxes only at the longer time scales. We then show how the Lagrangian temperature can be represented as a stochastic process, with a deterministic portion determined by the low frequency atmospheric forcing and a white noise perturbation. This is in line with previous studies of the ocean surface response to stochastic wind forcing. What distinguishes the present model is the deterministic part, which must account for the gradual cooling of the water parcels.

  8. SOLAR AND METEOROLOGICAL SURFACE OBSERVATION NETWORK (SAMSON) FOR NC, VA

    EPA Science Inventory

    Solar and Meteorological Surface Observational Network (SAMSON) v1.0 data for 6 NWS stations in North Carolina and 4 in Virginia. Hourly solar elements are: extraterrestrial horizontal and extraterrestrial direct normal radiation; global, diffuse, and direct normal radiation. Met...

  9. Estimating Long Term Surface Soil Moisture in the GCIP Area From Satellite Microwave Observations

    NASA Technical Reports Server (NTRS)

    Owe, Manfred; deJeu, Vrije; VandeGriend, Adriaan A.

    2000-01-01

    Soil moisture is an important component of the water and energy balances of the Earth's surface. Furthermore, it has been identified as a parameter of significant potential for improving the accuracy of large-scale land surface-atmosphere interaction models. However, accurate estimates of surface soil moisture are often difficult to make, especially at large spatial scales. Soil moisture is a highly variable land surface parameter, and while point measurements are usually accurate, they are representative only of the immediate site which was sampled. Simple averaging of point values to obtain spatial means often leads to substantial errors. Since remotely sensed observations are already a spatially averaged or areally integrated value, they are ideally suited for measuring land surface parameters, and as such, are a logical input to regional or larger scale land process models. A nine-year database of surface soil moisture is being developed for the Central United States from satellite microwave observations. This region forms much of the GCIP study area, and contains most of the Mississippi, Rio Grande, and Red River drainages. Daytime and nighttime microwave brightness temperatures were observed at a frequency of 6.6 GHz, by the Scanning Multichannel Microwave Radiometer (SMMR), onboard the Nimbus 7 satellite. The life of the SMMR instrument spanned from Nov. 1978 to Aug. 1987. At 6.6 GHz, the instrument provided a spatial resolution of approximately 150 km, and an orbital frequency over any pixel-sized area of about 2 daytime and 2 nighttime passes per week. Ground measurements of surface soil moisture from various locations throughout the study area are used to calibrate the microwave observations. Because ground measurements are usually only single point values, and since the time of satellite coverage does not always coincide with the ground measurements, the soil moisture data were used to calibrate a regional water balance for the top 1, 5, and 10 cm

  10. Large Scale Surface Radiation Budget from Satellite Observation

    NASA Technical Reports Server (NTRS)

    Pinker, R. T.

    1995-01-01

    During the current reporting period, the focus of our work was on preparing and testing an improved version of our Surface Radiation Budget algorithm for processing the ISCCP D1 data routinely at the SRB Satellite Data Analysis Center (SDAC) at NASA Langley Research Center. The major issues addressed are related to gap filling and to testing whether observations made from ERBE could be used to improve current procedures of converting narrowband observations, as available from ISCCP, into broadband observations at the TOA. The criteria for selecting the optimal version are to be based on results of intercomparison with ground truth.

  11. Observation of Organic Molecules at the Aerosol Surface.

    PubMed

    Wu, Yajing; Li, Wanyi; Xu, Bolei; Li, Xia; Wang, Han; McNeill, V Faye; Rao, Yi; Dai, Hai-Lung

    2016-06-16

    Organic molecules at the gas-particle interface of atmospheric aerosols influence the heterogeneous chemistry of the aerosol and impact climate properties. The ability to probe the molecules at the aerosol particle surface in situ therefore is important but has been proven challenging. We report the first successful observations of molecules at the surface of laboratory-generated aerosols suspended in air using the surface-sensitive technique second harmonic light scattering (SHS). As a demonstration, we detect trans-4-[4-(dibutylamino)styryl]-1-methylpyridinium iodide and determine its population and adsorption free energy at the surface of submicron aerosol particles. This work illustrates a new and versatile experimental approach for studying how aerosol composition may affect the atmospheric properties. PMID:27249662

  12. Sunspots, Space Weather and Climate

    NASA Technical Reports Server (NTRS)

    Hathaway, David H.

    2009-01-01

    Four hundred years ago this year the telescope was first used for astronomical observations. Within a year, Galileo in Italy and Harriot in England reported seeing spots on the surface of the Sun. Yet, it took over 230 years of observations before a Swiss amateur astronomer noticed that the sunspots increased and decreased in number over a period of about 11 years. Within 15 years of this discovery of the sunspot cycle astronomers made the first observations of a flare on the surface of the Sun. In the 150 years since that discovery we have learned much about sunspots, the sunspot cycle, and the Sun s explosive events - solar flares, prominence eruptions and coronal mass ejections that usually accompany the sunspots. These events produce what is called Space Weather. The conditions in space are dramatically affected by these events. Space Weather can damage our satellites, harm our astronauts, and affect our lives here on the surface of planet Earth. Long term changes in the sunspot cycle have been linked to changes in our climate as well. In this public lecture I will give an introduction to sunspots, the sunspot cycle, space weather, and the possible impact of solar variability on our climate.

  13. Weathering of Martian Evaporites

    NASA Technical Reports Server (NTRS)

    Wentworth, S. J.; Velbel, M. A.; Thomas-Keprta, K. L.; Longazo, T. G.; McKay, D. S.

    2001-01-01

    Evaporites in martian meteorites contain weathering or alteration features that may provide clues about the martian near-surface environment over time. Additional information is contained in the original extended abstract.

  14. Moored surface buoy observations of the diurnal warm layer

    NASA Astrophysics Data System (ADS)

    Prytherch, J.; Farrar, J. T.; Weller, R. A.

    2013-09-01

    An extensive data set is used to examine the dynamics of diurnal warming in the upper ocean. The data set comprises more than 4700 days of measurements at five sites in the tropics and subtropics, obtained from surface moorings equipped to make comprehensive meteorological, incoming solar and infrared radiation, and high-resolution subsurface temperature (and, in some cases, velocity) measurements. The observations, which include surface warmings of up to 3.4°C, are compared with a selection of existing models of the diurnal warm layer (DWL). A simple one-layer physical model is shown to give a reasonable estimate of both the magnitude of diurnal surface warming (model-observation correlation 0.88) and the structure and temporal evolution of the DWL. Novel observations of velocity shear obtained during 346 days at one site, incorporating high-resolution (1 m) upper ocean (5-15 m) acoustic Doppler current profile measurements, are also shown to be in reasonable agreement with estimates from the physical model (daily maximum shear model-observation correlation 0.77). Physics-based improvements to the one-layer model (incorporation of rotation and freshwater terms) are discussed, though they do not provide significant improvements against the observations reported here. The simplicity and limitations of the physical model are used to discuss DWL dynamics. The physical model is shown to give better model performance under the range of forcing conditions experienced across the five sites than the more empirical models.

  15. On comparison of modeled surface flux variations to aircraft observations.

    SciTech Connect

    Song, J.; Wesely, M. L.; Environmental Research; Northern Illinois Univ.

    2003-07-30

    Evaluation of models of air-surface exchange is facilitated by an accurate match of areas simulated with those seen by micrometeorological flux measurements. Here, spatial variations in fluxes estimated with the parameterized subgrid-scale surface (PASS) flux model were compared to flux variations seen aboard aircraft above the Walnut River Watershed (WRW) in Kansas. Despite interference by atmospheric eddies, the areas where the modeled sensible and latent heat fluxes were most highly correlated with the aircraft flux estimates were upwind of the flight segments. To assess whether applying a footprint function to the surface values would improve the model evaluation, a two-dimensional correlation distribution was used to identify the locations and relative importance of contributing modeled surface pixels upwind of each segment of the flight path. The agreement between modeled surface fluxes and aircraft measurements was improved when upwind fluxes were weighted with an optimized footprint parameter {var_phi}, which can be estimated from wind profiler data and surface eddy covariance. Variations of the flight-observed flux were consistently greater than those modeled at the surface, perhaps because of the smoothing effect of using 1 km pixels in the model. In addition, limited flight legs prevented sufficient filtering of the effects of atmospheric convection, possibly accounting for some of the more prominent changes in fluxes measured along the flight paths.

  16. Lunar Surface Habitat Configuration Assessment: Methodology and Observations

    NASA Technical Reports Server (NTRS)

    Carpenter, Amanda

    2008-01-01

    The Lunar Habitat Configuration Assessment evaluated the major habitat approaches that were conceptually developed during the Lunar Architecture Team II Study. The objective of the configuration assessment was to identify desired features, operational considerations, and risks to derive habitat requirements. This assessment only considered operations pertaining to the lunar surface and did not consider all habitat conceptual designs developed. To examine multiple architectures, the Habitation Focus Element Team defined several adequate concepts which warranted the need for a method to assess the various configurations. The fundamental requirement designed into each concept included the functional and operational capability to support a crew of four on a six-month lunar surface mission; however, other conceptual aspects were diverse in comparison. The methodology utilized for this assessment consisted of defining figure of merits, providing relevant information, and establishing a scoring system. In summary, the assessment considered the geometric configuration of each concept to determine the complexity of unloading, handling, mobility, leveling, aligning, mating to other elements, and the accessibility to the lunar surface. In theory, the assessment was designed to derive habitat requirements, potential technology development needs and identify risks associated with living and working on the lunar surface. Although the results were more subjective opposed to objective, the assessment provided insightful observations for further assessments and trade studies of lunar surface habitats. This overall methodology and resulting observations will be describe in detail and illustrative examples will be discussed.

  17. Assessment and ground-based correction of the Level-3 MODIS daily aerosol optical depth: Implications in the context of surface solar radiation prediction and numerical weather modeling

    NASA Astrophysics Data System (ADS)

    Ruiz-Arias, J. A.; Dudhia, J.; Pozo-Vazquez, D.

    2012-12-01

    The Level-3 MODIS (L3M) aerosol optical depth (AOD) product offers interesting features for surface solar radiation and numerical weather modeling applications. However, most of the validation efforts so far have been focused on Level-2 (L2M) products and only rarely on L3M. We compare the Collection 5.1 L3M AOD (Terra dataset) available since 2000 against observed daily AOD values at 550 nm from more than 500 AERONET ground stations. The aim is to check the advisability of this dataset for surface solar radiation calculations using numerical weather models. Overall, the mean error (ME) is 0.03 (17%, relative to the mean observed AOD), with a root mean square error (RMSE) of 0.14 (73%), albeit these values are found highly dependent on geographical region. For AOD values above about 0.3 the expected error (EE) is found higher than that of the L2M product. We propose specific parameterizations for the EE of the L3M AOD, as well as for both its ME and its standard deviation. We also found that, roughly, half of the uncertainty of the L3M AOD dataset might be attributable to its sub-pixel variability. Finally, we used a radiative transfer model to investigate how the L3M AOD uncertainty propagates into the direct normal (DNI) and global horizontal (GHI) irradiances evaluation. Overall, for AODs smaller than 0.5, the induced uncertainty in DNI due to AOD alone is below 15% on average, and below 5% for GHI (for a solar zenith angle of 30 degrees). But the uncertainty in AOD is highly spatially variable, so is that in irradiance. These results suggest the necessity of a correction method to reduce the bias of the L3M AOD. Ground-based AOD measurements can be also used in a data fusion procedure. We present the results of a preliminary study using optimal interpolation of L3M daily AOD data based on daily AERONET AOD measurements in the US in the period since June to August 2009. The method removes the data gaps in the original dataset, assesses the spatial distribution

  18. World weather program

    NASA Technical Reports Server (NTRS)

    1980-01-01

    A brief description of the Global Weather Experiment is presented. The world weather watch program plan is described and includes a global observing system, a global data processing system, a global telecommunication system, and a voluntary cooperation program. A summary of Federal Agency plans and programs to meet the challenges of international meteorology for the two year period, FY 1980-1981, is presented.

  19. The Home Weather Station.

    ERIC Educational Resources Information Center

    Steinke, Steven D.

    1991-01-01

    Described is how an amateur weather observer measures and records temperature and precipitation at a well-equipped, backyard weather station. Directions for building an instrument shelter and a description of the instruments needed for measuring temperature and precipitation are included. (KR)

  20. Observation of Sea Ice Surface Thermal States Under Cloud Cover

    NASA Technical Reports Server (NTRS)

    Nghiem, S. V.; Perovich, D. K.; Gow, A. J.; Kwok, R.; Barber, D. G.; Comiso, J. C.; Zukor, Dorothy J. (Technical Monitor)

    2001-01-01

    Clouds interfere with the distribution of short-wave and long-wave radiations over sea ice, and thereby strongly affect the surface energy balance in polar regions. To evaluate the overall effects of clouds on climatic feedback processes in the atmosphere-ice-ocean system, the challenge is to observe sea ice surface thermal states under both clear sky and cloudy conditions. From laboratory experiments, we show that C-band radar (transparent to clouds) backscatter is very sensitive to the surface temperature of first-year sea ice. The effect of sea ice surface temperature on the magnitude of backscatter change depends on the thermal regimes of sea ice thermodynamic states. For the temperature range above the mirabilite (Na2SO4.10H20) crystallization point (-8.2 C), C-band data show sea ice backscatter changes by 8-10 dB for incident angles from 20 to 35 deg at both horizontal and vertical polarizations. For temperatures below the mirabilite point but above the crystallization point of MgCl2.8H2O (-18.0 C), relatively strong backwater changes between 4-6 dB are observed. These backscatter changes correspond to approximately 8 C change in temperature for both cases. The backscattering mechanism is related to the temperature which determines the thermodynamic distribution of brine volume in the sea ice surface layer. The backscatter is positively correlated to temperature and the process is reversible with thermodynamic variations such as diurnal insolation effects. From two different dates in May 1993 with clear and overcast conditions determined by the Advanced Very High Resolution Radiometer (AVHRR), concurrent Earth Resources Satellite 1 (ERS-1) C-band ice observed with increases in backscatter over first-year sea ice, and verified by increases in in-situ sea ice surface temperatures measured at the Collaborative-Interdisciplinary Cryosphere Experiment (C-ICE) site.

  1. Estimates of surface methane emissions over Europe using observed surface concentrations and the FLEXPART trajectory model

    NASA Astrophysics Data System (ADS)

    Weaver, C. J.; Kiemle, C.; Kawa, S. R.; Aalto, T.; Necki, J.; Steinbacher, M.; Arduini, J.; Apadula, F.; Berkhout, H.; Hatakka, J.; O'Doherty, S.

    2013-12-01

    We use surface methane observations from nine European ground stations, and the FLEXPART Lagrangian transport model to obtain surface methane emissions for 2010. Our inversion shows the strongest emissions from the Netherlands and the coal mines in Upper Silesia Poland. This is qualitatively consistent with the EDGAR surface flux inventory. We also report significant surface fluxes from wetlands in southern Finland during July and August and reduced wetland fluxes later in the year. Our simulated methane surface concentration captures at least half of the daily variability in the observations, suggesting that the transport model is correctly simulating the regional transport pathways over Europe. We also use our trajectory model to determine whether future space-based remote sensing instruments (MERLIN) will be able to detect both natural and anthropogenic changes in the surface flux strengths.

  2. OBSERVED POLARIZATION OF BROWN DWARFS SUGGESTS LOW SURFACE GRAVITY

    SciTech Connect

    Sengupta, Sujan; Marley, Mark S. E-mail: Mark.S.Marley@NASA.go

    2010-10-20

    Light scattering by atmospheric dust particles is responsible for the polarization observed in some L dwarfs. Whether this polarization arises from an inhomogeneous distribution of dust across the disk or an oblate shape induced by rotation remains unclear. Here, we argue that the latter case is plausible and, for many L dwarfs, the more likely one. Furthermore, evolutionary models of mature field L dwarfs predict surface gravities ranging from about 200 to 2500 m s{sup -2} (corresponding to masses of {approx}15-70 M {sub Jupiter}). Yet comparison of observed spectra to available synthetic spectra often does not permit more precise determination of the surface gravity of individual field L dwarfs, leading to important uncertainties in their properties. Since rotationally induced non-sphericity, which gives rise to non-zero disk-integrated polarization, is more pronounced at lower gravities, polarization is a promising low gravity indicator. Here, we combine a rigorous multiple scattering analysis with a self-consistent cloudy atmospheric model and observationally inferred rotational velocities and find that the observed optical polarization can be explained if the surface gravity of the polarized objects is about 300 m s{sup -2} or less, potentially providing a new method for constraining L dwarf masses.

  3. Wind Measurement and Archival under the Automated Surface Observing System (ASOS): User Concerns and Opportunity for Improvement.

    NASA Astrophysics Data System (ADS)

    Powell, Mark D.

    1993-04-01

    The National Weather Service, as a part of its modernization effort, is implementing the Automated Surface Observing System (ASOS). Much discussion has occurred about various aspects of ASOS versus the current system of manual and automated observations. Based upon a study of the ASOS specifications and an informal survey of potential ASOS winddata users, defects of the wind sampling and archival strategy chosen for ASOS are discussed in terms of their impact on various user groups. Limitations include: 1) hourly observation average periods that do not conform to international recommendations for wind reporting made by the World Meteorological Organization, 2) no regular archival of high-resolution data-potentially valuable research data are destroyed if not identified within a 12-h period, and 3) no emergency power for operation in severe weather conditions. An alternative sampling and archiving strategy is recommended that benefits a wider cross section of users, without detracting from aviation and forecast service requirements, at a cost of less than 1% of the original ASOS portion of the weather service modernization budget.

  4. Wind measurement and archival under the Automated Surface Observing System (ASOS): User concerns and opportunity for improvement

    SciTech Connect

    Powell, M.D. )

    1993-04-01

    The National Weather Service, as a part of its modernization effort, is implementing the Automated Surface Observing System (ASOS). Much discussion has occurred about various aspects of ASOS versus the current system of manual and automated observations. Based upon a study of the ASOS specifications and an informal survey of potential ASOS wind data users, defects of the wind sampling and archival strategy chosen for ASOS are discussed in terms of their impact on various user groups. Limitations include: (1) hourly observation average periods that do not conform to international recommendations for wind reporting made by the World Meteorological Organization, (2) no regular archival of high-resolution data-potentially valuable research data are destroyed if not identified within a 12-h period, and (3) no emergency power for operation in severe weather conditions. An alternative sampling and archiving strategy is recommended that benefits a wider cross section of users, without detracting from aviation and forecast service requirements, at a cost of less than 1 % of the original ASOS portion of the weather service modernization budget.

  5. Global Surface Thermal Inertia Derived from Dawn VIR Observations

    NASA Astrophysics Data System (ADS)

    Titus, T. N.; Becker, K. J.; Anderson, J.; Capria, M.; Tosi, F.; Prettyman, T. H.; De Sanctis, M. C.; Palomba, E.; Grassi, D.; Capaccioni, F.; Ammannito, E.; Combe, J.; McCord, T. B.; Li, J. Y.; Russell, C. T.; Raymond, C. A.

    2012-12-01

    Comparisons of surface temperatures, derived from Dawn [1] Visible and Infrared Mapping Spectrometer (VIR-MS) [2] observations , to thermal models suggest that Vesta generally has a low-thermal-inertia surface, between 25 and 35 J m^-2 K^-1 s^-½, consistent with a thick layer of fine-grain material [3]. Temperatures were calculated using a Bayesian approach to nonlinear inversion as described by Tosi et al. [4]. In order to compare observed temperatures of Vesta to model calculations, several geometric and photometric parameters must be known or estimated. These include local mean solar time, latitude, local slope, bond bolometric albedo, and the effective emissivity at 5μm. Local time, latitude, and local slope are calculated using the USGS ISIS software system [5]. We employ a multi-layered thermal-diffusion model called 'KRC' [6], which has been used extensively in the study of Martian thermophysical properties. This thermal model is easily modified for use with Vesta by replacing the Martian ephemeris input with the Vesta ephemeris and disabling the atmosphere. This model calculates surface temperatures throughout an entire Vesta year for specific sets of slope, azimuth, latitude and elevation, and a range of albedo and thermal-inertia values. The ranges of albedo and thermal inertia values create temperature indices that are closely matched to the dates and times observed by VIR. Based on observed temperatures and best-fit KRC thermal models, estimates of the annual mean surface temperatures were found to range from 176 K - 188 K for flat zenith-facing equatorial surfaces, but these temperatures can drop as low as 112 K for polar-facing slopes at mid-latitudes. [7] In this work, we will compare observed temperatures of the surface of Vesta (using data acquired by Dawn VIR-MS [2] during the approach, survey, high-altitude mapping and departure phases) to model temperature results using the KRC thermal model [5]. Where possible, temperature observations from

  6. Surface circulation in the northeast Atlantic as observed with drifters

    NASA Astrophysics Data System (ADS)

    Otto, L.; Van Aken, H. M.

    1996-04-01

    ARGOS surface drifter data from the northern parts of the northeast Atlantic over the years 1990-1993 have been analysed. The drifters had a drogue at a depth of 15 or 30 m. These data cover well over 10 drifter years. The overall drift appeared to be towards the northeast. Analysis by geographic area and by season revealed regional and temporal variations of both the mean flow and the eddy statistics. In winter the drifter velocities had a tendency towards higher values, probably due to increased wind speeds. Highest eddy kinetic energy was found in the deep Iceland Basin, where an extension of the Sub-Arctic front was observed, while the lowest eddy kinetic energy was observed over the shallower Rockall Plateau. The strongest mean surface velocities were found in the Iceland Basin, just west of the Rockall Plateau. They were connected with the Sub-Arctic front in this region. No evidence was found of westward transport of surface water across the Reykjanes Ridge towards the Irminger Sea. Two drifters were observed to leave the area across the Iceland-Faroe Ridge, flowing eastwards over the northern Faroes slope, whereas two drifters left the area through the Faroe-Shetland Channel. The small banks in the area appeared to generate anti-cyclonic surface circulation on the scale of these banks. Over the larger Rockall Bank no preference for cyclonic circulation was found. The eddy kinetic energy was highest over the deep Iceland Basin where transient eddies were found with scalar velocities well over 20 cm s -1, while the Rockall Plateau seems to be an "eddy desert". The dispersion due to the temporal variability of the Lagrangian surface velocity could well be modelled with the simple Taylor's theory, with a good fit of the data to the theoretical lines for timescales of 0.25-40 days.

  7. Surface wind observations affected by agricultural development over Northwest China

    NASA Astrophysics Data System (ADS)

    Han, Songjun; Tang, Qiuhong; Zhang, Xuezhen; Xu, Di; Kou, Lihang

    2016-05-01

    Meteorological stations in Northwest China are surrounded by large proportions of cultivated land. The relations between the change of surface wind speed and the cultivated land fractions (CF) within a 4 km radius at 135 meteorological stations over arid Northwest China are investigated. Stations with larger CF experienced larger declines in surface wind speed from 1960 to 2007. Compared with the wind speed variation in the Tibetan Plateau where agricultural development is negligible, stations with low CF show similar variation, whereas the wind speed at stations with large CF illustrates a sharp decrease in the 1970s–1980s, during which irrigated agriculture developed rapidly. The observed wind speed at the station surrounded by irrigated fields in the Jingtai Irrigation District, shows a rapid wind speed decrease during the same period when the irrigated area expanded. By contrast, rapid wind decrease is not observed at a nearby station with minimal influence of agricultural development.

  8. ATLAS-3 correlative measurement opportunities with UARS and surface observations

    NASA Technical Reports Server (NTRS)

    Harrison, Edwin F.; Denn, Fred M.; Gibson, Gary G.

    1995-01-01

    The third ATmospheric Laboratory for Applications and Science (ATLAS-3) mission was flown aboard the Space Shuttle launched on November 3, 1994. The mission length was approximately 10 days and 22 hours. The ATLAS-3 Earth-viewing instruments provided a large number of measurements which were nearly coincident with observations from experiments on the Upper Atmosphere Research Satellite (UARS). Based on ATLAS-3 instrument operating schedules, simulations were performed to determine when and where correlative measurements occurred between ATLAS and UARS instruments, and between ATLAS and surface observations. Results of these orbital and instrument simulations provide valuable information for scientists to compare measurements between various instruments on the two satellites and at selected surface sites.

  9. Space Weather Simulators Developed at NICT : the Solar Surface-Solar Wind Coupling Model and the Next Generation Magnetosphere-Ionosphere Coupling Model

    NASA Astrophysics Data System (ADS)

    Den, Mitsue; Nagatsuma, Tsutomu; Watari, Shinichi; Tanaka, Takashi; Ishii, Mamoru; Kubo, Yuki; Kubota, Yasubumi; Washimi, Haruichi

    We report two global MHD simulators developed at NICT (National Institute of Information and Communications Technology): one is for the solar surface-solar wind coupling system and the other is for the magnetosphere-ionosphere coupling system. One important feature of our simulation model is the 3-D grid system, which has no polar singularity despite of a spherical grid configuration. By this grid system, fine grids can be allocated near the inner boundary which represents the sun or the earth. Some complicated magnetic structures on the solar surface is closely related with the solar disturbances, and in the same way the ionospheric aurora is closely related with the the magnetospheric reconfiguration processes. In views of these situation, it is very crucial for both models to achieve the simultaneous implementations for the fine grid structure on the inner boundary and the wide range grids in global configuration. For the solar surface-solar wind coupling system, the observed magnetic field data are input at the inner boundary, and the solar wind structure can be updated at every day by optimizing the simulation code. For the magnetospheric model, we are developing "the next generation" realtime MHD simulation system. The model is developed by NICT and co-workers, and the extreme phenomena such as the magnetopause crossing are simulated successfully. For the magnetic disturbance event, the westward traveling surge, the most characteristic feature of the substorm, is reproduced quite realistically. In this paper, we describe those two space weather simulator systems and represent several numerical results obtained by using these models.

  10. Constraints on the Global-scale Chemical Weathering State of Mars From TES Results Based on Spectral Analysis of Chemically Weathered Basalts

    NASA Astrophysics Data System (ADS)

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

    2005-12-01

    On Earth, subaerially exposed basaltic rocks (from arid-to-tropical regions) develop weathering rinds and rock coatings that affect spectroscopic measurements of their natural surfaces. Similarly, basaltic rocks and basaltic soil particles on Mars may have rinds and coatings that are spectroscopically observable. Thermal emission spectroscopy, because it provides information about the composition and structure of silicate and non-silicate minerals and mineraloids, provides a useful perspective on the mineralogy of weathered surfaces; reconciliation of the emission spectral features of weathered surfaces with observations from other datasets is critical to interpretations of thermal emission spectral features of Mars. In this study, we investigate the thermal emission (6-25 μm) and visible/near-infrared (VNIR) (0.4-2.5 μm) spectroscopic features of fresh and weathered surfaces of rock samples from the Columbia River Basalt Group (CRBG). VNIR spectra of weathered rock surfaces are brighter and redder than fresh rock surfaces, but contain no evidence for neoformation of clay minerals within subaerially exposed, weathered surfaces. In contrast, thermal emission spectroscopy suggests an enrichment of clay minerals in weathered surfaces. Also, thermal emission spectroscopy indicates the presence of glass-like materials in many weathered surfaces, which likely correspond to amorphous weathering products present within fractures, as coatings on minerals, or as coatings on the rocks themselves. These results have important implications for interpretation of TES and THEMIS data of Mars, including: 1) glasses and clays detected on Mars from thermal infrared spectra may correspond to poorly crystalline weathering products within chemically weathered rock surfaces, 2) chemically weathered surfaces of basalts may appear oxidized but clay-poor to VNIR datasets, and 3) the differential chemical breakdown of primary phases can affect interpretations of the remaining primary rock

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

    NASA Astrophysics Data System (ADS)

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

    2012-03-01

    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.

  12. Experimental Observation of Bohr’s Nonlinear Fluidic Surface Oscillation

    PubMed Central

    Moon, Songky; Shin, Younghoon; Kwak, Hojeong; Yang, Juhee; Lee, Sang-Bum; Kim, Soyun; An, Kyungwon

    2016-01-01

    Niels Bohr in the early stage of his career developed a nonlinear theory of fluidic surface oscillation in order to study surface tension of liquids. His theory includes the nonlinear interaction between multipolar surface oscillation modes, surpassing the linear theory of Rayleigh and Lamb. It predicts a specific normalized magnitude of 0.416η2 for an octapolar component, nonlinearly induced by a quadrupolar one with a magnitude of η much less than unity. No experimental confirmation on this prediction has been reported. Nonetheless, accurate determination of multipolar components is important as in optical fiber spinning, film blowing and recently in optofluidic microcavities for ray and wave chaos studies and photonics applications. Here, we report experimental verification of his theory. By using optical forward diffraction, we measured the cross-sectional boundary profiles at extreme positions of a surface-oscillating liquid column ejected from a deformed microscopic orifice. We obtained a coefficient of 0.42 ± 0.08 consistently under various experimental conditions. We also measured the resonance mode spectrum of a two-dimensional cavity formed by the cross-sectional segment of the liquid jet. The observed spectra agree well with wave calculations assuming a coefficient of 0.414 ± 0.011. Our measurements establish the first experimental observation of Bohr’s hydrodynamic theory. PMID:26803911

  13. Experimental Observation of Bohr’s Nonlinear Fluidic Surface Oscillation

    NASA Astrophysics Data System (ADS)

    Moon, Songky; Shin, Younghoon; Kwak, Hojeong; Yang, Juhee; Lee, Sang-Bum; Kim, Soyun; An, Kyungwon

    2016-01-01

    Niels Bohr in the early stage of his career developed a nonlinear theory of fluidic surface oscillation in order to study surface tension of liquids. His theory includes the nonlinear interaction between multipolar surface oscillation modes, surpassing the linear theory of Rayleigh and Lamb. It predicts a specific normalized magnitude of 0.416η2 for an octapolar component, nonlinearly induced by a quadrupolar one with a magnitude of η much less than unity. No experimental confirmation on this prediction has been reported. Nonetheless, accurate determination of multipolar components is important as in optical fiber spinning, film blowing and recently in optofluidic microcavities for ray and wave chaos studies and photonics applications. Here, we report experimental verification of his theory. By using optical forward diffraction, we measured the cross-sectional boundary profiles at extreme positions of a surface-oscillating liquid column ejected from a deformed microscopic orifice. We obtained a coefficient of 0.42 ± 0.08 consistently under various experimental conditions. We also measured the resonance mode spectrum of a two-dimensional cavity formed by the cross-sectional segment of the liquid jet. The observed spectra agree well with wave calculations assuming a coefficient of 0.414 ± 0.011. Our measurements establish the first experimental observation of Bohr’s hydrodynamic theory.

  14. Experimental Observation of Bohr's Nonlinear Fluidic Surface Oscillation.

    PubMed

    Moon, Songky; Shin, Younghoon; Kwak, Hojeong; Yang, Juhee; Lee, Sang-Bum; Kim, Soyun; An, Kyungwon

    2016-01-01

    Niels Bohr in the early stage of his career developed a nonlinear theory of fluidic surface oscillation in order to study surface tension of liquids. His theory includes the nonlinear interaction between multipolar surface oscillation modes, surpassing the linear theory of Rayleigh and Lamb. It predicts a specific normalized magnitude of 0.416η(2) for an octapolar component, nonlinearly induced by a quadrupolar one with a magnitude of η much less than unity. No experimental confirmation on this prediction has been reported. Nonetheless, accurate determination of multipolar components is important as in optical fiber spinning, film blowing and recently in optofluidic microcavities for ray and wave chaos studies and photonics applications. Here, we report experimental verification of his theory. By using optical forward diffraction, we measured the cross-sectional boundary profiles at extreme positions of a surface-oscillating liquid column ejected from a deformed microscopic orifice. We obtained a coefficient of 0.42 ± 0.08 consistently under various experimental conditions. We also measured the resonance mode spectrum of a two-dimensional cavity formed by the cross-sectional segment of the liquid jet. The observed spectra agree well with wave calculations assuming a coefficient of 0.414 ± 0.011. Our measurements establish the first experimental observation of Bohr's hydrodynamic theory. PMID:26803911

  15. CIRs Observed by MSL/RAD on the Martian Surface

    NASA Astrophysics Data System (ADS)

    Lohf, Henning; Zeitlin, Cary; Rafkin, Scot; Koehler, Jan; Posner, Arik; Hassler, Donald M.; Heber, Bernd; Ehresmann, Bent; Wimmer-Schweingruber, Robert; Guo, Jingnan; Appel, Jan Kristoffer

    2016-07-01

    Co-rotating Interaction Regions (CIRs) are recurrent Stream Interaction Regions in the solar wind which are stable transient plasma structures lasting several solar rotations. They can modulate Galactic Cosmic Rays (GCRs) and to some extent result in a modulation of GCR induced secondary energetic particles on the Martian surface. The Mars Science Laboratory/ Radiation Assessment Detector (MSL/RAD) has been measuring the Martian Surface Radiation Environment for more than three years and observes this modulation effect. We will show that the effect of CIRs can be measured on the Martian surface with MSL/RAD and this can be used to derive the arrival times of CIRs at Mars. These can provide (limited) solar wind plasma properties in the vicinity of Mars and thus serve as important constraints for modeling atmospheric response to variations in the solar wind. We use multi spacecraft observations of the solar wind and compare them with the heliospheric MHD Model ENLIL to verify that a certain class of dose rate variation we see on the Martian surface is due to CIRs. We use ballistic back-mapping as well as a time-shift algorithm to map the plasma properties measured at individual spacecraft locations and times to Mars. We compare these predictions with those of the CCMC ENLIL heliospheric MHD simulations.

  16. TIMS observations of surface emissivity in HAPEX-Sahel

    NASA Technical Reports Server (NTRS)

    Schmugge, Thomas; Hook, Simon; Kahle, Anne

    1995-01-01

    The Thermal Infrared Multispectral Scanner (TIMS) was flown on the NASA C-130 aircraft for a series of 12 flights during HAPEX-Sahel at altitudes ranging from 0.25 to 6 km (0.6 to 15 m resolution). TIMS provides coverage of the 8 to 12 micrometer thermal infrared band in 6 contiguous channels. Thus it is possible to observe the spectral behavior of the surface emissivity over this wavelength interval.

  17. Observations of Ocean surface response to Hurricane Igor: A Salty Tropical Cyclone Wake observed from Space

    NASA Astrophysics Data System (ADS)

    Reul, N.; Quilfen, Y.; Chapron, B.; Vialard, J.; Vincent, E.; Tenerelli, J.; Boyer de Montégut, C.; Vandemark, D.; Lengaigne, M.

    2012-04-01

    The upper ocean response to a moving hurricane is studied using satellite and in situ observations. Sea surface salinity response is emphasized using Soil Moisture and Ocean Salinity Sensor data acquired before and after the passing of Igor, a category 5 hurricane that attained wind speeds of 136 knots in September 2010. Post minus pre-hurricane satellite estimates of sea surface salinity reveal a strong surface salinity enhancement of ~1 practical salinity unit over a ~89000 km2 ocean surface area located on the right-hand side quadrant of the storm as it passed over the Amazon and Orinoco freshwater plume. The presence of this salty wake is associated with the erosion of the freshwater plume by the hurricane-induced mixing. The strong surface layer erosion as detected from space on the right-hand side storm quadrant is confirmed by in situ observation from Argo float profilers. The thermal, density and ocean color wakes are also evaluated and exhibit very consistent patterns with the sea surface salinity wake. As Igor over passed the plume on its left-hand side quadrants, the presence of a thick barrier layer below the plume inhibited mixing and significantly reduced the surface cooling in the wake of the storm, which limited the surface cooling negative feedback on Igor intensification. With this demonstrative example, we show that the new sea surface salinity measurements from space can be very useful as a complementary dataset to help predicting Tropical cyclone intensification in thick barrier layer area, such as the western tropical Atlantic.

  18. Space Weathering in the Mercurian Environment

    NASA Technical Reports Server (NTRS)

    Noble, S. K.; Pieters, C. M.

    2001-01-01

    Space weathering processes are known to be important on the Moon. These processes both create the lunar regolith and alter its optical properties. Like the Moon, Mercury has no atmosphere to protect it from the harsh space environment and therefore it is expected that it will also incur the effects of space weathering. However, there are many important differences between the environments of Mercury and the Moon. These environmental differences will almost certainly affect the weathering processes and the products of those processes. It should be possible to observe the effects of these differences in Vis (visible)/NIR (near infrared) spectra of the type expected to be returned by MESSENGER. More importantly, understanding these weathering processes and their consequences is essential for evaluating the spectral data returned from MESSENGER and other missions in order to determine the mineralogy and the Fe content of the Mercurian surface. Additional information is contained in the original extended abstract.

  19. Arecibo radar observations of Martian surface characteristics near the equator

    NASA Technical Reports Server (NTRS)

    Simpson, R. A.; Tyler, G. L.; Campbell, D. B.

    1978-01-01

    Mars radar observations at 12.6-cm wavelength indicate that many of what were potential Viking landing sites along the planet's equator are rougher than interpretations of Mariner 9 images suggested. Root mean square surface slopes are typically 5 degrees in the region bounded by 160 and 200 degrees W, 0 and 12 degrees S. From Tharsis Montes west to 160 degrees W, radar-scattering characteristics suggest extreme roughness on small scales, perhaps exceeding 10 degrees in rms magnitude. East of Tharsis and north of Valles Marineris the surface is smooth, with values of rms slope as low as 1 degree; the elevation of this plateau was too high for a Viking landing. Study of spectral shapes indicates the Hagfors scattering law remains the best descriptor of quasi-specular surface scattering properties in an average sense; widespread variations in the surface argue against its indiscriminate use, however. Backscattering at moderate (25-40 degrees) incidence angles was studied qualitatively and was found to be significantly above the level predicted by a strictly quasi-specular (e.g., Hagfors) process; it also is variable over the surface.

  20. Probing surface properties of Jupiter Trojans by polarimetric observations

    NASA Astrophysics Data System (ADS)

    Belskaya, I.; Bagnulo, S.; Stinson, A.; Christou, A.; Muinonen, K.

    2014-07-01

    We present the first polarimetric observations of six Jupiter Trojans, namely (588) Achilles, (1583) Antilochus, (3548) Eurybates, (4543) Phoinix, (6545) 1986 TR_6, and (21601) 1998 XO_{89}. All these objects belong to the L4 population of Jupiter Trojans and have diameters in the range of 50-160 km (Grav et al. 2011). The observations were carried out in 2013 at ESO VLT. Each object was observed at 3-4 different phase angles in the phase-angle range from 7 deg up to 11-12 deg, the largest possible phase angles in the ground-based observations of Trojans. Observations were made in the R band with a typical accuracy of 0.05 %. We have measured negative polarization branch for each object with polarization minima varying from -1 % to -1.3 %. The polarization-phase-angle behavior of the observed Trojans is found to be very similar to that of some low-albedo main-belt asteroids, in particular, the P-type asteroids. We compare photometric and polarimetric phase dependencies of Trojans to the phase curves of inner and outer Solar System bodies. Possible relationships of phase-curve parameters with albedos and spectral properties are investigated. Constraints on the surface properties of Jupiter Trojans from the polarimetric observations are discussed.

  1. Observation of dynamic water microadsorption on Au surface

    SciTech Connect

    Huang, Xiaokang Gupta, Gaurav; Gao, Weixiang; Tran, Van; Nguyen, Bang; McCormick, Eric; Cui, Yongjie; Yang, Yinbao; Hall, Craig; Isom, Harold

    2014-05-15

    Experimental and theoretical research on water wettability, adsorption, and condensation on solid surfaces has been ongoing for many decades because of the availability of new materials, new detection and measurement techniques, novel applications, and different scales of dimensions. Au is a metal of special interest because it is chemically inert, has a high surface energy, is highly conductive, and has a relatively high melting point. It has wide applications in semiconductor integrated circuitry, microelectromechanical systems, microfluidics, biochips, jewelry, coinage, and even dental restoration. Therefore, its surface condition, wettability, wear resistance, lubrication, and friction attract a lot of attention from both scientists and engineers. In this paper, the authors experimentally investigated Au{sub 2}O{sub 3} growth, wettability, roughness, and adsorption utilizing atomic force microscopy, scanning electron microscopy, reflectance spectrometry, and contact angle measurement. Samples were made using a GaAs substrate. Utilizing a super-hydrophilic Au surface and the proper surface conditions of the surrounding GaAs, dynamic microadsorption of water on the Au surface was observed in a clean room environment. The Au surface area can be as small as 12 μm{sup 2}. The adsorbed water was collected by the GaAs groove structure and then redistributed around the structure. A model was developed to qualitatively describe the dynamic microadsorption process. The effective adsorption rate was estimated by modeling and experimental data. Devices for moisture collection and a liquid channel can be made by properly arranging the wettabilities or contact angles of different materials. These novel devices will be very useful in microfluid applications or biochips.

  2. Structure of precipitating systems over Taiwan’s complex terrain during Typhoon Morakot (2009) as revealed by weather radar and rain gauge observations

    NASA Astrophysics Data System (ADS)

    Liou, Yu-Chieng; Wang, Tai-Chi Chen; Tsai, Yi-Chun; Tang, Yu-Shuang; Lin, Pay-Liam; Lee, Yung-An

    2013-12-01

    This study documents from an observational perspective the structure of precipitation systems over the complex topography of Taiwan as Typhoon Morakot (2009) impinged on the island on 8 August 2009. An advanced multiple-Doppler radar synthesis technique particularly designed for dealing with non-flat surfaces is applied to analyze the three-dimensional wind fields over the ocean and terrain. In the northern and southern portion of the analysis domain where the mountain slope is relatively gentle and steep, respectively, the radar reflectivity measurements indicate that the precipitation systems exhibit very distinct features, namely, horizontal translation in the north and abrupt intensification in the south. While still far from the southern mountainous region, a north-south oscillation of an east-west-oriented band of strong radar reflectivity (>40 dBZ) with a horizontal span of 20 km is observed. Along the mountain slopes, the band of strong radar reflectivity has a much wider north-south extent. Both the radar and rain gauge observations show that the major precipitation is primarily confined to the windward side of the mountains. An analysis of the saturated Brunt-Väisälä frequency reveals that the upstream atmosphere is statically unstable, which implies that the lifting of the incoming convective cells by the topography will easily trigger precipitation. Thus, most of the moisture will be consumed before the air reaches the leeward side of the mountains. The long duration and the wide range of heavy precipitation in the mountainous regions resulted in a record-breaking average (over the gauges) rainfall amount of 2000 mm over 4 days. The prevailing winds approaching the mountains are from the west. The cross-barrier wind speed has a maximum (∼40 m s-1) above the mountain crest that can be reasonably explained by a simplified shallow water model. The capability of applying the weather radar to provide a reliable quantitative estimate of the rainfall over

  3. Diurnal Variations of Titan's Surface Temperatures From Cassini -CIRS Observations

    NASA Astrophysics Data System (ADS)

    Cottini, Valeria; Nixon, Conor; Jennings, Don; Anderson, Carrie; Samuelson, Robert; Irwin, Patrick; Flasar, F. Michael

    The Cassini Composite Infrared Spectrometer (CIRS) observations of Saturn's largest moon, Titan, are providing us with the ability to detect the surface temperature of the planet by studying its outgoing radiance through a spectral window in the thermal infrared at 19 m (530 cm-1) characterized by low opacity. Since the first acquisitions of CIRS Titan data the in-strument has gathered a large amount of spectra covering a wide range of latitudes, longitudes and local times. We retrieve the surface temperature and the atmospheric temperature pro-file by modeling proper zonally averaged spectra of nadir observations with radiative transfer computations. Our forward model uses the correlated-k approximation for spectral opacity to calculate the emitted radiance, including contributions from collision induced pairs of CH4, N2 and H2, haze, and gaseous emission lines (Irwin et al. 2008). The retrieval method uses a non-linear least-squares optimal estimation technique to iteratively adjust the model parameters to achieve a spectral fit (Rodgers 2000). We show an accurate selection of the wide amount of data available in terms of footprint diameter on the planet and observational conditions, together with the retrieved results. Our results represent formal retrievals of surface brightness temperatures from the Cassini CIRS dataset using a full radiative transfer treatment, and we compare to the earlier findings of Jennings et al. (2009). The application of our methodology over wide areas has increased the planet coverage and accuracy of our knowledge of Titan's surface brightness temperature. In particular we had the chance to look for diurnal variations in surface temperature around the equator: a trend with slowly increasing temperature toward the late afternoon reveals that diurnal temperature changes are present on Titan surface. References: Irwin, P.G.J., et al.: "The NEMESIS planetary atmosphere radiative transfer and retrieval tool" (2008). JQSRT, Vol. 109, pp

  4. Differentiating the roles of photooxidation and biodegradation in the weathering of Light Louisiana Sweet crude oil in surface water from the Deepwater Horizon site.

    PubMed

    Bacosa, Hernando P; Erdner, Deana L; Liu, Zhanfei

    2015-06-15

    We determined the contributions of photooxidation and biodegradation to the weathering of Light Louisiana Sweet crude oil by incubating surface water from the Deepwater Horizon site under natural sunlight and temperature conditions. N-alkane biodegradation rate constants were ca. ten-fold higher than the photooxidation rate constants. For the 2-3 ring and 4-5 ring polycyclic aromatic hydrocarbons (PAHs), photooxidation rate constants were 0.08-0.98day(-1) and 0.01-0.07day(-1), respectively. The dispersant Corexit enhanced degradation of n-alkanes but not of PAHs. Compared to biodegradation, photooxidation increased transformation of 4-5 ring PAHs by 70% and 3-4 ring alkylated PAHs by 36%. For the first time we observed that sunlight inhibited biodegradation of pristane and phytane, possibly due to inhibition of the bacteria that can degrade branched-alkanes. This study provides quantitative measures of oil degradation under relevant field conditions crucial for understanding and modeling the fate of spilled oil in the northern Gulf of Mexico. PMID:25899525

  5. Conversion electron and X-ray Mössbauer studies of the corrosion products and surface modifications in stainless and weathering steels

    NASA Astrophysics Data System (ADS)

    Cook, D. C.

    1986-02-01

    The study of the corrosion products formed on the surface of Type 316 stainless steel exposed to chlorinated seawater for 18 days shows that ferrihydrite and lepidocrocite are the first oxides to form. The surface also shows the formation of a martensite when it is cleaned by light brushing before exposure. Samples of weathering steel, ASTM A242 Type 1, exposed for 51/2 years to either a marine or inland rural environment have been studied between 100K and 400K using CEMS and XMS. Different amounts of hydroxoxides are present on the surface of each sample. The steel exposed to the inland environment contains more α-FeOOH.

  6. Improving Numerical Weather Predictions of Summertime Precipitation Over the Southeastern U.S. Through a High-Resolution Initialization of the Surface State

    NASA Technical Reports Server (NTRS)

    Case, Jonathan L.; Kumar, Sujay V.; Krikishen, Jayanthi; Jedlovec, Gary J.

    2011-01-01

    It is hypothesized that high-resolution, accurate representations of surface properties such as soil moisture and sea surface temperature are necessary to improve simulations of summertime pulse-type convective precipitation in high resolution models. This paper presents model verification results of a case study period from June-August 2008 over the Southeastern U.S. using the Weather Research and Forecasting numerical weather prediction model. Experimental simulations initialized with high-resolution land surface fields from the NASA Land Information System (LIS) and sea surface temperature (SST) derived from the Moderate Resolution Imaging Spectroradiometer (MODIS) are compared to a set of control simulations initialized with interpolated fields from the National Centers for Environmental Prediction 12-km North American Mesoscale model. The LIS land surface and MODIS SSTs provide a more detailed surface initialization at a resolution comparable to the 4-km model grid spacing. Soil moisture from the LIS spin-up run is shown to respond better to the extreme rainfall of Tropical Storm Fay in August 2008 over the Florida peninsula. The LIS has slightly lower errors and higher anomaly correlations in the top soil layer, but exhibits a stronger dry bias in the root zone. The model sensitivity to the alternative surface initial conditions is examined for a sample case, showing that the LIS/MODIS data substantially impact surface and boundary layer properties.

  7. Advanced Methods of Observing Surface Plasmon Polaritons and Magnons

    NASA Astrophysics Data System (ADS)

    Moghaddam, Abolghasem Mobaraki

    Available from UMI in association with The British Library. Requires signed TDF. The primary objectives of this thesis are the investigation of the theoretical and experimental aspects of the design and construction of advanced techniques for the excitation of surface plasmon-polaritons, surface magneto -plasmon-polaritons and surface magnons. They involve on -line observation of these phenomena and to accomplish these goals, analytical studies of the characteristic behaviour of these phenomena have been undertaken. For excitations of surface plasmon- and surface magneto-plasmon-polaritons the most robust and conventional configuration, namely Prism-Medium-Air, coupled to a novel angle scan (prism spinning) method was employed. The system to be described here can automatically measure the reflectivity of a multilayer system over a range of angles that includes the resonance angle in an Attenuated Total Reflection (ATR) experiment. The computer procedure that controls the system is quite versatile so that it allows any right-angle prism of different angle or refractive index to be utilised. It also provided probes to check for optical alignment within the system. Moreover, it performs the angular scan many times and then averages the results in order to reduce the environmental and other possible sources of noise within the system. The mechanical side of the system is unique and could eventually be adopted as a marketable piece of equipment. It consists of a turntable for holding the prism-sample assembly and a drive motor in conjunction with a servo-potentiometer whose output not only operates the turntable but also sends a signal to a computer to measure accurately its position. The interface unit enables a computer to control automatically an angular scan ATR experiment for measuring the resonance reflectivity spectrum of a multilayer system. The interface unit uses an H-bridge switch formed by four bipolar power transistor and two small signal MOSFETs to convert

  8. A System for Monitoring and Forecasting Land Surface Phenology Using Time Series of JPSS VIIRS Observations and Its Applications

    NASA Astrophysics Data System (ADS)

    Zhang, X.; Yu, Y.; Liu, L.

    2015-12-01

    Land surface phenology quantifies seasonal dynamics of vegetation properties including the timing and magnitude of vegetation greenness from satellite observations. Over the last decade, historical time series of AVHRR and MODIS data has been used to characterize the seasonal and interannual variation in terrestrial ecosystems and their responses to a changing and variable climate. The Visible Infrared Imaging Radiometer Suite (VIIRS) instrument on board the operational JPSS satellites provides land surface observations in a timely fashion, which has the capability to monitor phenological development in near real time. This capability is particularly important for assisting agriculture, natural resource management, and land modeling for weather prediction systems. Here we introduce a system to monitor in real time and forecast in the short term phenological development based on daily VIIRS observations available with a one-day latency. The system integrates a climatological land surface phenology from long-term MODIS data and available VIIRS observations to simulate a set of potential temporal trajectories of greenness development at a given time and pixel. The greenness trajectories, which are qualified using daily two-band Enhanced Vegetation Index (EVI2), are applied to identify spring green leaf development and autumn color foliage status in real time and to predict the occurrence of future phenological events. This system currently monitors vegetation development across the North America every three days and makes prediction to 10 days ahead. We further introduce the applications of near real time spring green leaf and fall color foliage. Specifically, this system is used for tracing the crop progress across the United States, guiding the field observations in US National Phenology Network, servicing tourists for the observation of color fall foliage, and parameterizing seasonal surface physical conditions for numerical weather prediction models.

  9. Dust events in Arizona: Long-term satellite and surface observations, and the National Air Quality Forecasting Capability CMAQ simulations

    NASA Astrophysics Data System (ADS)

    Huang, M.; Tong, D.; Lee, P.; Pan, L.; Tang, Y.; Stajner, I.; Pierce, R. B.; McQueen, J.

    2015-12-01

    Dust events in Arizona: An analysis integrating satellite and surface weather and aerosol measurements, and National Air Quality Forecasting Capability CMAQ simulations Dust records in Arizona during 2005-2013 are developed using multiple observation datasets, including level 2 deep blue aerosol product by the Moderate Resolution Imaging Spectroradiometer (MODIS) and the in-situ measurements at the surface Air Quality System (AQS) and Interagency Monitoring of Protected Visual Environments (IMPROVE) sites in Phoenix. The satellite and surface aerosol observations were anti-correlated with three drought indicators (i.e., MODIS vegetation index, a European satellite soil moisture dataset, and Palmer Drought Severity Index). During the dusty year of 2007, we show that the dust events were stronger and more frequent in the afternoon hours than in the morning due to faster winds and drier soil, and the Sonoran and Chihuahuan deserts were important dust source regions during identified dust events in Phoenix as indicated by NOAA's Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) Model calculations. Based on these findings, we suggested a potential for use of satellite soil moisture and vegetation index products to interpret and predict dust activity. We also emphasized the importance of using hourly observations for better capturing dust events, and expect the hourly geostationary satellite observations in the future to well complement the current surface PM and meteorological observations considering their broader spatial coverage. Additionally, the performance of the National Air Quality Forecasting Capability (NAQFC) 12 km CMAQ model simulation is evaluated during a recent strong dust event in the western US accompanied by stratospheric ozone intrusion. The current modeling system well captured the temporal variability and the magnitude of aerosol concentrations during this event. Directions of integrating satellite weather and vegetation observations

  10. Seaglider observations of surface mixed layer physics and biogeochemistry

    NASA Astrophysics Data System (ADS)

    Damerell, Gillian; Heywood, Karen; Thompson, Andrew; Henson, Stephanie; Rumyantseva, Anya

    2013-04-01

    The Ocean Surface Mixing, Ocean Sub-mesoscale Interaction Study (OSMOSIS) aims to develop new, physically-based parameterisations of processes that deepen and shoal the ocean surface boundary layer. As part of this project, 2 Seagliders were deployed in September 2012 at the Porcupine Abyssal Plain (PAP) site in the North Atlantic, to measure the structure and evolution of the ocean surface boundary layer over the seasonal cycle. The gliders measured temperature, salinity, dissolved oxygen, dive-averaged currents, chlorophyll fluorescence, CDOM fluorescence and PAR. We present results from the first 6 months of the Seaglider deployments, examining particular case studies of deepening/shoaling events and their impact on the biogeochemistry. Shoaling events appear to be more abrupt than deepening events. We also discuss the water masses found in the area, in particular, the occurrences of Mediterranean Water observed at a depth of approximately 800 m. As a contribution to the GROOM project, we assess the advantages and challenges of maintaining a continuous glider-based multidisciplinary observing system at the PAP site, with 2 gliders being turned around approximately every 4 months.

  11. Thermophysical Properties of the Lunar Surface from Diviner Observations

    NASA Astrophysics Data System (ADS)

    Hayne, Paul; Bandfield, Joshua; Vasavada, Ashwin; Ghent, Rebecca; Siegler, Matthew; Williams, Jean-Pierre; Greenhagen, Benjamin; Aharonson, Oded; Paige, David

    2013-04-01

    Orbital thermal infrared measurements are sensitive to a variety of properties of the Moon's surface layer, including rock abundance, regolith cover and porosity, and small-scale surface roughness. With its multiple spectral channels and large dynamic temperature range, the Diviner Lunar Radiometer [1] on NASA's LRO spacecraft has enabled the first global, high-resolution maps of these important thermophysical properties. Here we present a summary of the results of Diviner's thermophysical investigation thus far. Maps of surface rock abundance show low typical values of <1% with higher abundances for recent craters and their blocky ejecta, as well as mass wasting on crater walls, rilles, and impact melt features [2]. The extent and abundance of surface rocks decrease systematically with crater age, and rocky surfaces are only preserved on the youngest craters (<1 Ga). We used nighttime regolith surface temperatures and eclipse cooling observations to constrain profiles of density and conductivity in the upper ~1 m, revealing a remarkably homogeneous subsurface structure [3]. Geographic variations in upper regolith density are nonetheless apparent. For example, buried rocks are suggested within young impact ejecta showing strong radar backscatter, high subsurface density, and a lack of surface rocks [2,4]. Rock fragmentation and regolith accumulation rates can be quantified by comparison of the Diviner data with published crater ages, yielding typical erosion rates which rapidly decrease from ~10 kg m-2 yr-1 for crater ages of ~1 Ma to ~1 mg m-2 yr-1 at ~1 Ga [4]. Variations in upper regolith density correlate with the ages of individual mare basalt units, suggesting this layer is actively processed by impacts on geologically short timescales, which may reveal age relationships previously unseen [5]. Vast cold regions surrounding fresh impact craters during lunar night (termed "cold spots") are only apparent in thermal infrared data [2]. These features cannot be

  12. Weathering in a Cup.

    ERIC Educational Resources Information Center

    Stadum, Carol J.

    1991-01-01

    Two easy student activities that demonstrate physical weathering by expansion are described. The first demonstrates ice wedging and the second root wedging. A list of the needed materials, procedure, and observations are included. (KR)

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

    USGS Publications Warehouse

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

    2008-01-01

    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.

  14. Shortwave spectral radiative forcing of cumulus clouds from surface observations

    NASA Astrophysics Data System (ADS)

    Kassianov, E.; Barnard, J.; Berg, L. K.; Long, C. N.; Flynn, C.

    2011-04-01

    The spectral changes of the shortwave total, direct and diffuse cloud radiative forcing (CRF) at surface are examined for the first time using spectrally resolved all-sky flux observations and clear-sky fluxes. The latter are computed applying a physically based approach, which accounts for the spectral changes of aerosol optical properties and surface albedo. Application of this approach to 13 summertime days with single-layer continental cumuli demonstrates: (i) the substantial contribution of the diffuse component to the total CRF, (ii) the well-defined spectral variations of total CRF in the visible spectral region, and (iii) the strong statistical relationship between spectral (500 nm) and shortwave broadband values of total CRF. Our results suggest that the framework based on the visible narrowband fluxes can provide important radiative quantities for rigorous evaluation of radiative transfer parameterizations and also can be applied for estimation of the shortwave broadband CRF.

  15. Ocean Surface Carbon Dioxide Fugacity Observed from Space

    NASA Technical Reports Server (NTRS)

    Liu, W. Timothy; Xie, Xiaosu

    2014-01-01

    We have developed and validated a statistical model to estimate the fugacity (or partial pressure) of carbon dioxide (CO2) at sea surface (pCO2sea) from space-based observations of sea surface temperature (SST), chlorophyll, and salinity. More than a quarter million in situ measurements coincident with satellite data were compiled to train and validate the model. We have produced and made accessible 9 years (2002-2010) of the pCO2sea at 0.5 degree resolutions daily over the global ocean. The results help to identify uncertainties in current JPL Carbon Monitoring System (CMS) model-based and bottom-up estimates over the ocean. The utility of the data to reveal multi-year and regional variability of the fugacity in relation to prevalent oceanic parameters is demonstrated.

  16. Isotopic excesses of proton-rich nuclei related to space weathering observed in a gas-rich meteorite Kapoeta

    SciTech Connect

    Hidaka, Hiroshi; Yoneda, Shigekazu E-mail: s-yoneda@kahaku.go.jp

    2014-05-10

    The idea that solar system materials were irradiated by solar cosmic rays from the early Sun has long been suggested, but is still questionable. In this study, Sr, Ba, Ce, Nd, Sm, and Gd isotopic compositions of sequential acid leachates from the Kapoeta meteorite (howardite) were determined to find systematic and correlated variations in their isotopic abundances of proton-rich nuclei, leading to an understanding of the irradiation condition by cosmic rays. Significantly large excesses of proton-rich isotopes (p-isotopes), {sup 84}Sr, {sup 130}Ba, {sup 132}Ba, {sup 136}Ce, {sup 138}Ce, and {sup 144}Sm, were observed, particularly in the first chemical separate, which possibly leached out of the very shallow layer within a few μm from the surface of regolith grains in the sample. The results reveal the production of p-isotopes through the interaction of solar cosmic rays with the superficial region of the regolith grains before the formation of the Kapoeta meteorite parent body, suggesting strong activity in the early Sun.

  17. Some observations on vortex-ring collisions upon inclined surfaces

    NASA Astrophysics Data System (ADS)

    New, T. H.; Shi, Shengxian; Zang, B.

    2016-06-01

    This paper reports upon a laser-induced fluorescence visualization and time-resolved particle image velocimetry study to resolve the detailed dynamics associated with Re = 2000 and 4000 circular vortex rings colliding with 30°-75° inclined surfaces. Two-dimensional visualization results show that larger inclination angles lead to increasingly rapid size reduction in the primary vortex-ring core closer to the surface, faster formation of the secondary vortex-ring core, and subsequent ingestion by the former. In contrast, primary vortex-ring core further away from the surface becomes physically larger and incoherent more rapidly, with slower formation and entrainment of the secondary vortex-ring core. Interestingly, a vortex dipole and small vortex-ring-like structure are produced for the largest inclination angle of 75°, possibly due to vortex disconnection and reconnection processes. Results taken along the non-inclined plane show significant bulging of the primary vortex-ring cores when the inclination angle increases from 30° onwards. More importantly, additional vortex cores are observed to entwine with the primary vortex-ring core and provide strong direct evidence for the bi-helical vortex line flow mechanism put forward by Lim (Exp Fluids 7:453-463, 1989). Lastly, the behaviour of the primary and secondary vortex-ring cores further away from the surface is highly sensitive towards the state of the bi-helical lines compressed at that region. Strong compression driven by circumferential flows due to large inclination angles may explain the unique flow structures and behaviour observed for 75° inclination angle here.

  18. Probing the Arctic - insights from combining surface station observations and model analyses

    NASA Astrophysics Data System (ADS)

    Haiden, Thomas

    2016-04-01

    The Arctic system is changing, and to understand the mechanisms and feedback processes contributing to these changes, an integrated spatial-temporal approach is needed. International Arctic Systems for Observing the Atmosphere (IASOA) observatories are predominantly located at coastal locations, which makes their data potentially relevant for both land and ocean areas. Numerical weather prediction (NWP) model analyses and forecasts provide a means of relating such point measurements to the atmospheric state over a larger area. Using ECMWF's re-analysis and forecasting system it is shown how comparison of station observations with NWP output provides insight into the flow-dependence of spatial representativeness. It also reveals systematic shortcomings in the model which need to be considered when the model is used as a tool to gain a better understanding of relevant physical processes. Well-known modelling challenges in the Arctic are discussed, such as the representation of low cloud, in particular at low temperatures, as well as ice/ocean/land-atmosphere interactions. The importance of surface-based observations, such as provided by IASOA observatories, is considered in light of the scientific plan for the Year of Polar Prediction 2017-19.

  19. Interannual variation of the surface temperature of tropical forests from satellite observations

    DOE PAGESBeta

    Gao, Huilin; Zhang, Shuai; Fu, Rong; Li, Wenhong; Dickinson, Robert E.

    2016-01-01

    Land surface temperatures (LSTs) within tropical forests contribute to climate variations. However, observational data are very limited in such regions. This study used passive microwave remote sensing data from the Special Sensor Microwave/Imager (SSM/I) and the Special Sensor Microwave Imager Sounder (SSMIS), providing observations under all weather conditions, to investigate the LST over the Amazon and Congo rainforests. The SSM/I and SSMIS data were collected from 1996 to 2012. The morning and afternoon observations from passive microwave remote sensing facilitate the investigation of the interannual changes of LST anomalies on a diurnal basis. As a result of the variability ofmore » cloud cover and the corresponding reduction of solar radiation, the afternoon LST anomalies tend to vary more than the morning LST anomalies. The dominant spatial and temporal patterns for interseasonal variations of the LST anomalies over the tropical rainforest were analyzed. The impacts of droughts and El Niños on this LST were also investigated. Lastly, the differences between early morning and late afternoon LST anomalies were identified by the remote sensing product, with the morning LST anomalies controlled by humidity (according to comparisons with the National Centers for Environmental Prediction (NCEP) reanalysis data).« less

  20. Interannual variation of the surface temperature of tropical forests from satellite observations

    SciTech Connect

    Gao, Huilin; Zhang, Shuai; Fu, Rong; Li, Wenhong; Dickinson, Robert E.

    2016-01-01

    Land surface temperatures (LSTs) within tropical forests contribute to climate variations. However, observational data are very limited in such regions. This study used passive microwave remote sensing data from the Special Sensor Microwave/Imager (SSM/I) and the Special Sensor Microwave Imager Sounder (SSMIS), providing observations under all weather conditions, to investigate the LST over the Amazon and Congo rainforests. The SSM/I and SSMIS data were collected from 1996 to 2012. The morning and afternoon observations from passive microwave remote sensing facilitate the investigation of the interannual changes of LST anomalies on a diurnal basis. As a result of the variability of cloud cover and the corresponding reduction of solar radiation, the afternoon LST anomalies tend to vary more than the morning LST anomalies. The dominant spatial and temporal patterns for interseasonal variations of the LST anomalies over the tropical rainforest were analyzed. The impacts of droughts and El Niños on this LST were also investigated. Lastly, the differences between early morning and late afternoon LST anomalies were identified by the remote sensing product, with the morning LST anomalies controlled by humidity (according to comparisons with the National Centers for Environmental Prediction (NCEP) reanalysis data).

  1. Hyperspectral Observations of Land Surfaces Using Ground-based, Airborne, and Satellite Sensors

    NASA Astrophysics Data System (ADS)

    Knuteson, R. O.; Best, F. A.; Revercomb, H. E.; Tobin, D. C.

    2006-12-01

    The University of Wisconsin-Madison Space Science and Engineering Center (UW-SSEC) has helped pioneer the use of high spectral resolution infrared spectrometers for application to atmospheric and surface remote sensing. This paper is focused on observations of land surface infrared emission from high spectral resolution measurements collected over the past 15 years using airborne, ground-based, and satellite platforms. The earliest data was collected by the High-resolution Interferometer Sounder (HIS), an instrument designed in the 1980s for operation on the NASA ER-2 high altitude aircraft. The HIS was replaced in the late 1990s by the Scanning-HIS instrument which has flown on the NASA ER-2, WB-57, DC-8, and Scaled Composites Proteus aircraft and continues to support field campaigns, such as those for EOS Terra, Aqua, and Aura validation. Since 1995 the UW-SSEC has fielded a ground-based Atmospheric Emitted Radiance Interferometer (AERI) in a research vehicle (the AERIBAGO) which has allowed for direct field measurements of land surface emission from a height of about 16 ft above the ground. Several ground-based and aircraft campaigns were conducted to survey the region surrounding the ARM Southern Great Plains site in north central Oklahoma. The ground- based AERIBAGO has also participated in surface emissivity campaigns in the Western U.S.. Since 2002, the NASA Atmospheric InfraRed Sounder (AIRS) has provided similar measurements from the Aqua platform in an afternoon sun-synchronous polar orbit. Ground-based and airborne observations are being used to validate the land surface products derived from the AIRS observations. These cal/val activities are in preparation for similar measurements anticipated from the operational Cross-track InfraRed Sounder (CrIS) on the NPOESS Preparatory Platform (NPP), expected to be launched in 2008. Moreover, high spectral infrared observations will soon be made by the Infrared Atmospheric Sounder Interferometer (IASI) on the

  2. Observation of 2nd Schumann eigenmode on Titan's surface

    NASA Astrophysics Data System (ADS)

    Béghin, C.; Wattieaux, G.; Grard, R.; Hamelin, M.; Lebreton, J. P.

    2013-10-01

    This work presents the results obtained from an updated data analysis of the observations of extremely low frequency (ELF) electromagnetic waves performed with the HASI-PWA (Huygens Atmospheric Structure and Permittivity, Wave and Altimetry) instrumentation after Huygens Probe landing on Titan's surface in January 2005. The most significant signals observed at around 36 Hz throughout the descent in the atmosphere have been extensively analyzed for several years, and subsequently interpreted as the signature of a Schumann resonance, although the latter exhibits atypical peculiarities compared with those known on Earth. The usual depicting methods of space wave data used so far could not allow for retrieving the presence of weak signals when Huygens was at rest for 32 min on Titan's surface. Whereas the expected signal seems hidden within the instrumental noise, we show that a careful statistical analysis of the amplitude distribution of the 418 spectral density samples of the 36 Hz line reveals abnormal characteristics compared to other frequencies. This behavior is shown to occur under propitious circumstances due to the characteristics of the onboard data conversion processes into digital telemetry counts, namely 8-bit dynamic after logarithm compression of the DFT (Discrete Fourier Transform) of ELF waveforms. Since this phenomenon is observed only at the frequency bin around 36 Hz, we demonstrate that the Schumann resonance, seen in the atmosphere within the same band is still present on the surface, albeit with a much smaller amplitude compared to that measured before and a few seconds after the impact, because the electric dipole is thought to have been stabilized ten seconds later almost horizontally until the end of the measurements.

  3. Observation of 2nd Schumann eigenmode on Titan's surface

    NASA Astrophysics Data System (ADS)

    Béghin, C.; Wattieaux, G.; Grard, R.; Hamelin, M.; Lebreton, J. P.

    2013-04-01

    This works presents the results obtained from an updated data analysis of the observations of Extremely Low Frequency (ELF) electromagnetic waves performed with the HASI-PWA (Huygens Atmospheric Structure and Permittivity, Wave and Altimetry) instrumentation after Huygens Probe landing on Titan surface in January 2005. The most significant signals observed at around 36 Hz throughout the descent in the atmosphere have been extensively analyzed for several years, and subsequently interpreted as the signature of a Schumann resonance, although the latter exhibits atypical peculiarities compared with those known on Earth. The usual depicting methods of space wave data used so far could not allow retrieving the presence of weak signals when Huygens was at rest for 32 min on Titan's surface. Whereas the expected signal seems hidden within the instrumental noise, we show that a careful statistical analysis of the amplitude distribution of the 418 spectral density samples of the 36 Hz line reveals abnormal characteristics compared to other frequencies. This behavior is shown to occur under propitious circumstances due to the characteristics of the onboard data conversion processes into digital telemetry counts, namely 8-bit dynamic after logarithm compression of the DFT (Discrete Fourier Transform) of ELF waveforms. Since this phenomenon is observed only at the frequency bin around 36 Hz, we demonstrate that the Schumann resonance, seen in the atmosphere within the same band, is still present on the surface, albeit with a much smaller amplitude compared to that measured before and a few seconds after the impact, because the electric dipole is thought to have been stabilized ten seconds later almost horizontally until the end of the measurements.

  4. Turbulence as observed by concurrent measurements made at NSSL using weather radar, Doppler radar, Doppler lidar and aircraft

    NASA Technical Reports Server (NTRS)

    Lee, Jean T.

    1987-01-01

    As air traffic increases and aircraft capability increases in range and operating altitude, the exposure to weather hazards increases. Turbulence and wind shears are two of the most important of these hazards that must be taken into account if safe flight operations are to be accomplished. Beginning in the early 1960's, Project Rough Rider began thunderstorm investigations. Past and present efforts at the National Severe Storm Laboratory (NSSL) to measure these flight safety hazards and to describe the use of Doppler radar to detect and qualify these hazards are summarized. In particular, the evolution of the Doppler-measured radial velocity spectrum width and its applicability to the problem of safe flight is presented.

  5. Retrieval of the land surface-air temperature difference from high spatial resolution satellite observations over complex surfaces in the Tibetan Plateau

    NASA Astrophysics Data System (ADS)

    Zhang, Jie; Gao, Shiyang; Chen, Haishan; Yu, Jiahui; Tang, Qun

    2015-08-01

    The temperature difference between the surface and the air (dTsa) directly indicates the intensity and heat fluxes of land-atmosphere interaction. Considering the effects of surface characteristics and air condition on the surface temperature, using 1 km data from the MOD02 thermal infrared bands of the EOS/moderate-resolution imaging spectroradiometer (MODIS) on satellite Aqua, other MODIS products and temperatures observed from weather stations at 14:00 China standard time (CST), the study analyzes the relationships between dTsa and brightness temperature in the infrared atmospheric window band (Bt31 and Bt32), the water vapor band (Bt28), the atmospheric temperature band (Bt25), and the CO2 band (Bt34). A model estimating dTsa is built. The model coefficients are estimated for 96 stations representing 96 sets of surface and atmospheric conditions, and 71 sets of coefficients among them passing 90% confidence levels of estimating dTsa are selected as references. Combined with the probabilistic neural network (PNN) method and nine parameters reflecting surface characteristics in one season and month, the Tibetan Plateau surface is classified as 71 types with 71 sets of coefficients. PNN is certified an efficient classification method for multiple parameters and mass data. Based on PNN and estimated model, estimated dTsa shows 1.36°C root-mean-square error and a standard deviation of 0.74°C, and dTsa distribution exhibits all centers with peak value and valley value of European Centre for Medium-Range Weather Forecasts, MYD07, and simple regression model results, showing its superiority. The model is worthy of further exploration and application in an effort to advance the retrieval of surface energy fluxes from remote sensing.

  6. Land surface controls on afternoon precipitation diagnosed from observational data: Uncertainties and confounding factors

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The feedback between soil moisture and precipitation has long been a topic of interest due to its potential for improving weather and seasonal forecasts. The generally proposed mechanism assumes a control of soil moisture on precipitation via the partitioning of the surface fluxes (the Evaporative F...

  7. TES Observations of Chryse and Acidalia Planitiae: Multiple Working Hypotheses for Distributions of Surface Compositions

    NASA Technical Reports Server (NTRS)

    Wyatt, M. B.; Bandfield, J. L.; McSween, H. Y., Jr.; Christensen, P. R.; Moersch, J.

    2002-01-01

    A gradation of surface units represents either (1) an influx of basaltic sediment from southern highlands, deposited on andesitic volcanics, or (2) incompletely weathered basalt marking the geographic extent of submarine alteration of basaltic crust. Additional information is contained in the original extended abstract.

  8. Observations of Strong Surface Radar Ducts over the Persian Gulf.

    NASA Astrophysics Data System (ADS)

    Brooks, Ian M.; Goroch, Andreas K.; Rogers, David P.

    1999-09-01

    Ducting of microwave radiation is a common phenomenon over the oceans. The height and strength of the duct are controlling factors for radar propagation and must be determined accurately to assess propagation ranges. A surface evaporation duct commonly forms due to the large gradient in specific humidity just above the sea surface; a deeper surface-based or elevated duct frequently is associated with the sudden change in temperature and humidity across the boundary layer inversion.In April 1996 the U.K. Meteorological Office C-130 Hercules research aircraft took part in the U.S. Navy Ship Antisubmarine Warfare Readiness/Effectiveness Measuring exercise (SHAREM-115) in the Persian Gulf by providing meteorological support and making measurements for the study of electromagnetic and electro-optical propagation. The boundary layer structure over the Gulf is influenced strongly by the surrounding desert landmass. Warm dry air flows from the desert over the cooler waters of the Gulf. Heat loss to the surface results in the formation of a stable internal boundary layer. The layer evolves continuously along wind, eventually forming a new marine atmospheric boundary layer. The stable stratification suppresses vertical mixing, trapping moisture within the layer and leading to an increase in refractive index and the formation of a strong boundary layer duct. A surface evaporation duct coexists with the boundary layer duct.In this paper the authors present aircraft- and ship-based observations of both the surface evaporation and boundary layer ducts. A series of sawtooth aircraft profiles map the boundary layer structure and provide spatially distributed estimates of the duct depth. The boundary layer duct is found to have considerable spatial variability in both depth and strength, and to evolve along wind over distances significant to naval operations (100 km). The depth of the evaporation duct is derived from a bulk parameterization based on Monin-Obukhov similarity theory

  9. Geologic interpretation of new observations of the surface of Venus

    NASA Technical Reports Server (NTRS)

    Saunders, R. S.; Malin, M. C.

    1977-01-01

    New radar observations of the surface of Venus provide further evidence of a diverse and complex geologic evolution. The radar bright feature 'Beta' (24 deg N, 85 deg W) is seen to be a 700 km diameter region elevated a maximum of approximately 10 km relative to its surroundings with a 60 x 90 km wide depression at its summit. 'Beta' is interpreted to be a large volcanic construct, analogous to terrestrial and Martian shield volcanoes. Two large, quasi-circular areas of low reflectivity, examples of a class of features interpreted to be impact basins by previous investigators who were without the benefit of actual topographic information, are shown in altimetry maps to be depressions. Thus the term 'basin' can be applied, although we urge a non-genetic usage until more complete understanding of their origin is achieved through analysis of future observations.

  10. Wacky Weather

    ERIC Educational Resources Information Center

    Sabarre, Amy; Gulino, Jacqueline

    2013-01-01

    What do a leaf blower, water hose, fan, and ice cubes have in common? Ask the students who participated in an integrative science, technology, engineering, and mathematics (I-STEM) education unit, "Wacky Weather," and they will tell say "fun and severe weather"--words one might not have expected! The purpose of the unit…

  11. Space Weather

    NASA Technical Reports Server (NTRS)

    Gallagher, Dennis L.

    2010-01-01

    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.

  12. Aviation Weather Program (AWP)

    NASA Technical Reports Server (NTRS)

    Foote, Brant

    1993-01-01

    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.

  13. Global Monitoring of Martian Surface Albedo Changes from Orbital Observations

    NASA Astrophysics Data System (ADS)

    Geissler, P.; Enga, M.; Mukherjee, P.

    2013-12-01

    Martian surface changes were first observed from orbit during the Mariner 9 and Viking Orbiter missions. They were found to be caused by eolian processes, produced by deposition of dust during regional and global dust storms and subsequent darkening of the surface through erosion and transportation of dust and sand. The albedo changes accumulated in the 20 years between Viking and Mars Global Surveyor were sufficient to alter the global circulation of winds and the climate of Mars according to model calculations (Fenton et al., Nature 2007), but little was known about the timing or frequency of the changes. Since 1999, we have had the benefit of continuous monitoring by a series of orbiting spacecraft that continues today with Mars Reconnaissance Orbiter, Mars Odyssey, and Mars Express. Daily synoptic observations enable us to determine whether the surface albedo changes are gradual or episodic in nature and to record the seasons that the changes take place. High resolution images of surface morphology and atmospheric phenomena help identify the physical mechanisms responsible for the changes. From these data, we hope to learn the combinations of atmospheric conditions and sediment properties that produce surface changes on Mars and possibly predict when they will take place in the future. Martian surface changes are particularly conspicuous in low albedo terrain, where even a thin layer of bright dust brightens the surface drastically. Equatorial dark areas are repeatedly coated and recoated by dust, which is later shed from the surface by a variety of mechanisms. An example is Syrtis Major, suddenly buried in bright dust by the global dust storm of 2001. Persistent easterly winds blew much of the dust cover away over the course of the next Martian year, but episodic changes continue today, particularly during southern summer when regional dust storms are rife. Another such region is Solis Planum, south of the Valles Marineris, where changes take place

  14. Observations of swell influence on ocean surface roughness

    NASA Astrophysics Data System (ADS)

    Hwang, Paul A.

    2008-12-01

    Field measurements of the ocean surface wave spectrum focusing on the slope-contributing components are used to construct a spectral model of the ocean surface roughness. The spectral parameterization is established with the observed empirical power law relation between the dimensionless wave spectral density and wind speed. The power law parameters (proportionality coefficient and exponent) are shown to be modified by swell. Discussions are presented on the swell effects of spectral properties, including their wind speed dependence and swell modification of roughness components characterizing Bragg resonance and surface tilting in radar application. Several notable results include the following: (1) With increasing swell intensity, the spectral density increases in the long-wave portion and decreases in the short-wave portion of the intermediate-scale waves. (2) There is a nodal point with respect to swell impact in the wave number dependence of the coefficient and exponent of the spectral parameterization function in the vicinity of wave number near 3 rad/m, suggesting that waves about a couple of meters long are insensitive to swell influence. (3) Spectral density in the decimeter length scale becomes less sensitive to wind speed variation as swell intensity increases. (4) Increasing swell influence shifts wave breaking toward shorter and broader scales.

  15. Stratocumulus cloud height variations determined from surface and satellite observations

    NASA Technical Reports Server (NTRS)

    Minnis, Patrick; Young, David F.; Davies, R.; Blaskovic, M.; Albrecht, Bruce A.

    1990-01-01

    Determination of cloud-top heights from satellite-inferred cloud-top temperatures is a relatively straightforward procedure for a well-behaved troposphere. The assumption of a monotonically decreasing temperature with increasing altitude is commonly used to assign a height to a given cloud-top temperature. In the hybrid bispectral threshold method, or HBTM, Minnis et al. (1987) assume that the lapse rate for the troposphere is -6.5/Kkm and that the surface temperature which calibrated this lapse rate is the 24 hour mean of the observed or modeled clear-sky, equivalent blackbody temperature. The International Satellite Cloud Climatology Project (ISCCP) algorithm (Rossow et al., 1988) attempts a more realistic assignment of height by utilizing interpolations of analyzed temperature fields from the National Meteorological Center (NMC) to determine the temperature at a given level over the region of interest. Neither these nor other techniques have been tested to any useful extent. The First ISCCP Regional Experiment (FIRE) Intensive Field Observations (IFO) provide an excellent opportunity to assess satellite-derived cloud height results because of the availability of both direct and indirect cloud-top altitude data of known accuracy. The variations of cloud-top altitude during the Marine Stratocumulus IFO (MSIFO, June 29 to July 19, 1987) derived from surface, aircraft, and satellite data are examined.

  16. Observations of Radiative Cooling By Nitric Oxide and Carbon Dioxide in the E and F Regions: Implications for Space Weather and Space Climate

    NASA Astrophysics Data System (ADS)

    Mlynczak, M. G.; Hunt, L. A.; Russell, J. M., III

    2014-12-01

    Infrared emission by nitric oxide (NO, 5.3 um), carbon dioxide (CO2, 15 um), and atomic oxygen (O, 63 um) is the mechanism for radiative cooling of the thermosphere. Heat conduction transports energy from the warmer, higher layers of the thermosphere to lower layers where CO2 and NO ultimately radiate the energy. These radiative processes play a large role in governing the neutral temperature of the ionosphere E and F regions. The SABER instrument on the NASA TIMED satellite has been observing radiative cooling by NO and CO2 for 13 years. Substantial variability in the radiative cooling is observed on timescales ranging from one day to the 11-year solar cycle. Harmonics of the annual cycle are evident in the CO2 cooling rates, implying strong coupling to the lower atmosphere. Harmonics of the solar rotation period are evident in the NO cooling, but only during solar minimum conditions. To date the NO cooling data have been helpful in understanding space weather forecasts and the interaction of co-rotating interaction regions with the ionosphere. The cooling rate data will be reviewed in light of their observed variability over the past 13 years, including the implications for variations in the thermal structure of the E and F regions. The potential for development of proxies and empirical models of the NO and CO2 emissions will also be presented. Such models could become part of an overall space weather forecasting tool.

  17. Assimilation of Smos Observations to Generate a Prototype SMAP Level 4 Surface and Root-Zone Soil Moisture Product

    NASA Technical Reports Server (NTRS)

    Reichle, Rolf H.; De Lannoy, Gabrielle J. M.; Crow, Wade T.; Koster, Randal D.; Kimball, John

    2012-01-01

    The Soil Moisture Active and Passive (SMAP; [1]) mission is being implemented by NASA for launch in October 2014. The primary science objectives of SMAP are to enhance understanding of land surface controls on the water, energy and carbon cycles, and to determine their linkages. Moreover, the high-resolution soil moisture mapping provided by SMAP has practical applications in weather and seasonal climate prediction, agriculture, human health, drought and flood decision support. The Soil Moisture and Ocean Salinity (SMOS; [2]) mission was launched by ESA in November 2009 and has since been observing L-band (1.4 GHz) upwelling passive microwaves. In this paper we describe our use of SMOS brightness temperature observations to generate a prototype of the planned SMAP Level 4 Surface and Root-zone Soil Moisture (L4_SM) product [5].

  18. A systematic evaluation of the lagged effects of spatiotemporally relative surface weather types on wintertime cardiovascular-related mortality across 19 US cities.

    PubMed

    Lee, Cameron C

    2015-11-01

    Previous research using varying methods has shown that the day-to-day variability in cardiovascular (CV)-related mortality is correlated with a number of different meteorological variables, though these relationships can vary geographically. This research systematically examines the relationship between anomalous winter CV-related mortality and geographically and seasonally relative multivariate surface weather types derived from a recently developed gridded weather typing classification (GWTC) for cities in varying climate regions of the United States of America (USA). Results indicate that for all locations examined, during winter, a dry and cool (DC) weather type is significantly related to increased CV-related mortality, especially in the 2 weeks immediately after it occurs, with no apparent mortality displacement. Across the USA as a whole, the peak of this relationship is a 4.1% increase in CV-related mortality at a lag of 3 days. Spike days in CV-related mortality show similar trends, being over 50% more likely 2 to 4 days after the DC type occurs. A humid and warm (HW) weather type exhibited a significant and opposite relationship to that of DC. While these results for DC and HW were statistically significant at every location examined, the magnitudes were larger in the warmer locations. Among other weather types, Warm Front Passages (WFP) were also related to significant increases in CV-related mortality, especially 1 day after they occurred. Though this link was much more varied geographically than results found with DC or HW, it suggests that sequences of multiple DC days followed by WFP may result in increased CV-related mortality. PMID:25711484

  19. A systematic evaluation of the lagged effects of spatiotemporally relative surface weather types on wintertime cardiovascular-related mortality across 19 US cities

    NASA Astrophysics Data System (ADS)

    Lee, Cameron C.

    2015-11-01

    Previous research using varying methods has shown that the day-to-day variability in cardiovascular (CV)-related mortality is correlated with a number of different meteorological variables, though these relationships can vary geographically. This research systematically examines the relationship between anomalous winter CV-related mortality and geographically and seasonally relative multivariate surface weather types derived from a recently developed gridded weather typing classification (GWTC) for cities in varying climate regions of the United States of America (USA). Results indicate that for all locations examined, during winter, a dry and cool (DC) weather type is significantly related to increased CV-related mortality, especially in the 2 weeks immediately after it occurs, with no apparent mortality displacement. Across the USA as a whole, the peak of this relationship is a 4.1% increase in CV-related mortality at a lag of 3 days. Spike days in CV-related mortality show similar trends, being over 50% more likely 2 to 4 days after the DC type occurs. A humid and warm (HW) weather type exhibited a significant and opposite relationship to that of DC. While these results for DC and HW were statistically significant at every location examined, the magnitudes were larger in the warmer locations. Among other weather types, Warm Front Passages (WFP) were also related to significant increases in CV-related mortality, especially 1 day after they occurred. Though this link was much more varied geographically than results found with DC or HW, it suggests that sequences of multiple DC days followed by WFP may result in increased CV-related mortality.

  20. Global chemical weathering and associated P-release

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

    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)

  1. Observations of surface momentum exchange over the marginal-ice-zone and recommendations for its parameterization

    NASA Astrophysics Data System (ADS)

    Elvidge, A. D.; Renfrew, I. A.; Weiss, A. I.; Brooks, I. M.; Lachlan-Cope, T. A.; King, J. C.

    2015-10-01

    Comprehensive aircraft observations are used to characterise surface roughness over the Arctic marginal ice zone (MIZ) and consequently make recommendations for the parameterization of surface momentum exchange in the MIZ. These observations were gathered in the Barents Sea and Fram Strait from two aircraft as part of the Aerosol-Cloud Coupling And Climate Interactions in the Arctic (ACCACIA) project. They represent a doubling of the total number of such aircraft observations currently available over the Arctic MIZ. The eddy covariance method is used to derive estimates of the 10 m neutral drag coefficient (CDN10) from turbulent wind velocity measurements, and a novel method using albedo and surface temperature is employed to derive ice fraction. Peak surface roughness is found at ice fractions in the range 0.6 to 0.8 (with a mean interquartile range in CDN10 of 1.25 to 2.85 × 10-3). CDN10 as a function of ice fraction is found to be well approximated by the negatively skewed distribution provided by a leading parameterization scheme (Lüpkes et al., 2012) tailored for sea ice drag over the MIZ in which the two constituent components of drag - skin and form drag - are separately quantified. Current parameterization schemes used in the weather and climate models are compared with our results and the majority are found to be physically unjustified and unrepresentative. The Lüpkes et al. (2012) scheme is recommended in a computationally simple form, with adjusted parameter settings. A good agreement is found to hold for subsets of the data from different locations despite differences in sea ice conditions. Ice conditions in the Barents Sea, characterised by small, unconsolidated ice floes, are found to be associated with higher CDN10 values - especially at the higher ice fractions - than those of Fram Strait, where typically larger, smoother floes are observed. Consequently, the important influence of sea ice morphology and floe size on surface roughness is

  2. Observations of surface momentum exchange over the marginal ice zone and recommendations for its parametrisation

    NASA Astrophysics Data System (ADS)

    Elvidge, A. D.; Renfrew, I. A.; Weiss, A. I.; Brooks, I. M.; Lachlan-Cope, T. A.; King, J. C.

    2016-02-01

    Comprehensive aircraft observations are used to characterise surface roughness over the Arctic marginal ice zone (MIZ) and consequently make recommendations for the parametrisation of surface momentum exchange in the MIZ. These observations were gathered in the Barents Sea and Fram Strait from two aircraft as part of the Aerosol-Cloud Coupling And Climate Interactions in the Arctic (ACCACIA) project. They represent a doubling of the total number of such aircraft observations currently available over the Arctic MIZ. The eddy covariance method is used to derive estimates of the 10 m neutral drag coefficient (CDN10) from turbulent wind velocity measurements, and a novel method using albedo and surface temperature is employed to derive ice fraction. Peak surface roughness is found at ice fractions in the range 0.6 to 0.8 (with a mean interquartile range in CDN10 of 1.25 to 2.85 × 10-3). CDN10 as a function of ice fraction is found to be well approximated by the negatively skewed distribution provided by a leading parametrisation scheme (Lüpkes et al., 2012) tailored for sea-ice drag over the MIZ in which the two constituent components of drag - skin and form drag - are separately quantified. Current parametrisation schemes used in the weather and climate models are compared with our results and the majority are found to be physically unjustified and unrepresentative. The Lüpkes et al. (2012) scheme is recommended in a computationally simple form, with adjusted parameter settings. A good agreement holds for subsets of the data from different locations, despite differences in sea-ice conditions. Ice conditions in the Barents Sea, characterised by small, unconsolidated ice floes, are found to be associated with higher CDN10 values - especially at the higher ice fractions - than those of Fram Strait, where typically larger, smoother floes are observed. Consequently, the important influence of sea-ice morphology and floe size on surface roughness is recognised, and

  3. Rb Sr and K Ar systems of biotite in surface environments regulated by weathering processes with implications for isotopic dating and hydrological cycles of Sr isotopes

    NASA Astrophysics Data System (ADS)

    Jeong, Gi Young; Cheong, Chang-Sik; Kim, Jeongmin

    2006-09-01

    Biotite is widely used for Rb-Sr and K-Ar isotopic dating and influences Sr isotope geochemistry of hydrological regimes. The isotopic system of biotite behaves diversely in response to surface weathering; i.e. the complete preservation of original Rb-Sr and K-Ar isotopic ages or dramatic reduction. In this study, we have explored the relation between the behavior of isotopic systems and complex weathering processes of biotites in the weathering profiles distributed on the Mesozoic granitoids in South Korea. In the lower parts of the profiles, biotite in the early stages of weathering was transformed into either oxidized biotite or hydrobiotite, with a mass release of 87Sr and 40Ar forced by the rapid oxidation of ferrous iron. During the transformation to oxidized biotite, 87Sr and 40Ar were preferentially released relative to Rb and K, respectively, via solid-state diffusion through the biotite lattice, resulting in a drastic reduction of original isotopic age. The reduction of Rb-Sr age was greater than that of K-Ar age because K was preferentially released over Rb whereas 87Sr and 40Ar were released proportionally to each other. However, during the transformation of biotite to hydrobiotite (i.e., to regularly interstratified biotite-vermiculite), 87Sr, Rb, 40Ar, and K were completely retained in the alternating biotite interlayer, and thus the original isotopic age can be preserved. In the upper parts of the profiles, where iron oxidation was almost completed, 87Sr, Rb, 40Ar, and K were gradually and proportionally released, with no further significant change in isotopic age during the gradual transformation of the early-formed oxidized biotite into hydrobiotite and vermiculite or during their final decomposition to kaolinite. The ratios and amounts of isotopes released from weathered biotites are dependent upon the degree of iron oxidation and the pathways of mineralogical transformation. Regional and local variations in isotopic systems affected by particular

  4. Surface contour radar observations of the directional wave spectrum during Fasinex

    NASA Technical Reports Server (NTRS)

    Walsh, E. J.; Hancock, D. W., III; Hines, D. E.; Swift, R. N.; Scott, J. F.

    1988-01-01

    The surface control radar (SCR), a 36-GHz computer-controlled airborne radar which generates a false-color coded elevation map of the sea surface below the aircraft in real time, is described. The SCR turned out to be ideal for documenting the wave spectra during Fasinex (the Frontal Air-Sea Interaction Experiment) due to its high spatial resolution and rapid mapping capability over extensive areas. Synoptic weather maps for February 15-18, 1986 are presented.

  5. Dissolution rates of subsoil limestone in a doline on the Akiyoshi-dai Plateau, Japan: An approach from a weathering experiment, hydrological observations, and electrical resistivity tomography

    NASA Astrophysics Data System (ADS)

    Akiyama, Sanae; Hattanji, Tsuyoshi; Matsushi, Yuki; Matsukura, Yukinori

    2015-10-01

    This study aims at estimating the controlling factors for the denudation rates of limestone, which often forms solution dolines on karst tablelands. Our approaches include (1) electrical resistivity tomography (ERT) to reveal shallow subsurface structures and hydrological settings, (2) automated monitoring of volumetric water content in soil profiles and manual measurements of subsurface CO2 concentrations and soil water chemistry, and (3) a field weathering experiment using limestone tablets with the micro-weight loss technique for determining current denudation rates. The field experiment and monitoring were carried out over 768 days from 2009-2011 at four sites with varying topographic and hydrological conditions along the sideslope of a doline on the Akiyoshi-dai karst plateau in SW-Japan. The installation depths of the limestone tablets were 15 cm or 50 cm below the slope surface. The soil moisture conditions varied site by site. Water-saturated conditions continued for 40-50% of the whole experimental period at 50-cm depth of upper and middle sites, while only 0-10% of the experimental period was water-saturated at the other sites. Chemical analysis revealed that the soil water was chemically unsaturated with calcite for all the sites. Spatial differences in concentrations of CO2 in soil pore air were statistically less significant. The denudation rates of the buried limestone tablets were 17.7-21.9 mg cm- 2 a- 1 at the upper and middle slopes, where the soil was water-saturated for a long time after precipitation. The lowest denudation of 3.9 mg cm- 2 a- 1 was observed on lower slopes where soil was not capable of maintaining water at a near saturation level even after precipitation. Statistical analysis revealed that the denudation rates of the tablets were strongly controlled by the duration for which soil pores were saturated by water (the conditions defined here are degrees of water saturation greater than 97%). Electrical resistivity tomography

  6. An attempt to comprehend Martian weathering conditions through the analysis of terrestrial palagonite samples

    NASA Technical Reports Server (NTRS)

    Douglas, C.; Wright, I. P.; Bell, J. B.; Morris, R. V.; Golden, D. C.; Pillinger, C. T.

    1993-01-01

    Spectroscopic observations of the Martian surface in the invisible to near infrared (0.4-1.0 micron), coupled with measurements made by Viking, have shown that the surface is composed of a mixture of fine-grained weathered and nonweathered minerals. The majority of the weathered components are thought to be materials like smectite clays, scapolite, or palagonite. Until materials are returned for analysis there are two possible ways of proceeding with an investigation of Martian surface processes: (1) the study of weathering products in meteorites that have a Martian origin (SNC's), and (2) the analysis of certain terrestrial weathering products as analogs to the material found in SNC's, or predicted to be present on the Martian surface. We describe some preliminary measurements of the carbon chemistry of terrestrial palagonite samples that exhibit spectroscopic similarities with the Martian surface. The data should aid the understanding of weathering in SNC's and comparisons between terrestrial palagonites and the Martian surface.

  7. Assimilation of Satellite-Derived Skin Temperature Observations into Land Surface Models

    NASA Technical Reports Server (NTRS)

    Reichle, Rolf H.; Kumar, Sujay V.; Mahanama, P. P.; Koster, Randal D.; Liu, Q.

    2010-01-01

    Land surface (or "skin") temperature (LST) lies at the heart of the surface energy balance and is a key variable in weather and climate models. Here we assimilate LST retrievals from the International Satellite Cloud Climatology Project (ISCCP) into the Noah and Catchment (CLSM) land surface models using an ensemble-based, off-line land data assimilation system. LST is described very differently in the two models. A priori scaling and dynamic bias estimation approaches are applied because satellite and model LST typically exhibit different mean values and variability. Performance is measured against 27 months of in situ measurements from the Coordinated Energy and Water Cycle Observations Project at 48 stations. LST estimates from Noah and CLSM without data assimilation ("open loop") are comparable to each other and superior to that of ISCCP retrievals. For LST, RMSE values are 4.9 K (CLSM), 5.6 K (Noah), and 7.6 K (ISCCP), and anomaly correlation coefficients (R) are 0.62 (CLSM), 0.61 (Noah), and 0.52 (ISCCP). Assimilation of ISCCP retrievals provides modest yet statistically significant improvements (over open loop) of up to 0.7 K in RMSE and 0.05 in anomaly R. The skill of surface turbulent flux estimates from the assimilation integrations is essentially identical to the corresponding open loop skill. Noah assimilation estimates of ground heat flux, however, can be significantly worse than open loop estimates. Provided the assimilation system is properly adapted to each land model, the benefits from the assimilation of LST retrievals are comparable for both models.

  8. Surface topography estimated by inversion of satellite gravity gradiometry observations

    NASA Astrophysics Data System (ADS)

    Ramillien, Guillaume

    2015-04-01

    An integration of mass elements is presented for evaluating the six components of the 2-order gravity tensor (i.e., second derivatives of the Newtonian mass integral for the gravitational potential) created by an uneven sphere topography consisting of juxtaposed vertical prisms. The method is based on Legendre polynomial series with the originality of taking elastic compensation of the topography by the Earth's surface into account. The speed of computation of the polynomial series increases logically with the observing altitude from the source of anomaly. Such a forward modelling can be easily used for reduction of observed gravity gradient anomalies by the effects of any spherical interface of density. Moreover, an iterative least-square inversion of the observed gravity tensor values Γαβ is proposed to estimate a regional set of topographic heights. Several tests of recovery have been made by considering simulated gradiometry anomaly data, and for varying satellite altitudes and a priori levels of accuracy. In the case of GOCE-type gradiometry anomalies measured at an altitude of ~300 km, the search converges down to a stable and smooth topography after 20-30 iterations while the final r.m.s. error is ~100 m. The possibility of cumulating satellite information from different orbit geometries is also examined for improving the prediction.

  9. Daytime sensible heat flux estimation over heterogeneous surfaces using multitemporal land-surface temperature observations

    NASA Astrophysics Data System (ADS)

    Castellví, F.; Cammalleri, C.; Ciraolo, G.; Maltese, A.; Rossi, F.

    2016-05-01

    Equations based on surface renewal (SR) analysis to estimate the sensible heat flux (H) require as input the mean ramp amplitude and period observed in the ramp-like pattern of the air temperature measured at high frequency. A SR-based method to estimate sensible heat flux (HSR-LST) requiring only low-frequency measurements of the air temperature, horizontal mean wind speed, and land-surface temperature as input was derived and tested under unstable conditions over a heterogeneous canopy (olive grove). HSR-LST assumes that the mean ramp amplitude can be inferred from the difference between land-surface temperature and mean air temperature through a linear relationship and that the ramp frequency is related to a wind shear scale characteristic of the canopy flow. The land-surface temperature was retrieved by integrating in situ sensing measures of thermal infrared energy emitted by the surface. The performance of HSR-LST was analyzed against flux tower measurements collected at two heights (close to and well above the canopy top). Crucial parameters involved in HSR-LST, which define the above mentioned linear relationship, were explained using the canopy height and the land surface temperature observed at sunrise and sunset. Although the olive grove can behave as either an isothermal or anisothermal surface, HSR-LST performed close to H measured using the eddy covariance and the Bowen ratio energy balance methods. Root mean square differences between HSR-LST and measured H were of about 55 W m-2. Thus, by using multitemporal thermal acquisitions, HSR-LST appears to bypass inconsistency between land surface temperature and the mean aerodynamic temperature. The one-source bulk transfer formulation for estimating H performed reliable after calibration against the eddy covariance method. After calibration, the latter performed similar to the proposed SR-LST method.

  10. Modeling and surface observations of arsenic dispersion from a large Cu-smelter in southwestern Europe

    NASA Astrophysics Data System (ADS)

    Chen, Bing; Stein, Ariel F.; Castell, Nuria; de la Rosa, Jesus D.; Sanchez de la Campa, Ana M.; Gonzalez-Castanedo, Yolanda; Draxler, Roland R.

    2012-03-01

    Arsenic is a toxic element for human health. Consequently, a mean annual target level for arsenic at 6 ng m-3 in PM10 was established by the European Directive 2004/107/CE to take effect January 2013. Cu-smelters can contribute to one-third of total emissions of arsenic in the atmosphere. Surface observations taken near a large Cu-smelter in the city of Huelva (Spain) show hourly arsenic concentrations in the range of 0-20 ng m-3. The arsenic peaks of 20 ng m-3 are higher than values normally observed in urban areas around Europe by a factor of 10. The Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model has been employed to predict arsenic emissions, transport, and dispersion from the Cu-smelter. The model utilized outputs from different meteorological models and variations in the model physics options to simulate the uncertainty in the dispersion of the arsenic plume. Modeling outputs from the physics ensemble for each meteorological model driving HYSPLIT show the same number of arsenic peaks. HYSPLIT coupled with the Weather Research and Forecasting (WRF-ARW) meteorological output predicted the right number of peaks for arsenic concentration at the observation site. The best results were obtained when the WRF simulation used both four-dimensional data assimilation and surface analysis nudging. The prediction was good in local sea breeze circulations or when the flow was dominated by the synoptic scale prevailing winds. However, the predicted peak was delayed when the transport and dispersion was under the influence of an Atlantic cyclone. The calculated concentration map suggests that the plume from the Cu-smelter can cause arsenic pollution events in the city of Huelva as well as other cities and tourist areas in southwestern Spain.

  11. Linking the Weather Generator with Regional Climate Model

    NASA Astrophysics Data System (ADS)

    Dubrovsky, Martin; Farda, Ales; Skalak, Petr; Huth, Radan

    2013-04-01

    One of the downscaling approaches, which transform the raw outputs from the climate models (GCMs or RCMs) into data with more realistic structure, is based on linking the stochastic weather generator with the climate model output. The present contribution, in which the parametric daily surface weather generator (WG) M&Rfi is linked to the RCM output, follows two aims: (1) Validation of the new simulations of the present climate (1961-1990) made by the ALADIN-Climate Regional Climate Model at 25 km resolution. The WG parameters are derived from the RCM-simulated surface weather series and compared to those derived from weather series observed in 125 Czech meteorological stations. The set of WG parameters will include statistics of the surface temperature and precipitation series (including probability of wet day occurrence). (2) Presenting a methodology for linking the WG with RCM output. This methodology, which is based on merging information from observations and RCM, may be interpreted as a downscaling procedure, whose product is a gridded WG capable of producing realistic synthetic multivariate weather series for weather-ungauged locations. In this procedure, WG is calibrated with RCM-simulated multi-variate weather series in the first step, and the grid specific WG parameters are then de-biased by spatially interpolated correction factors based on comparison of WG parameters calibrated with gridded RCM weather series and spatially scarcer observations. The quality of the weather series produced by the resultant gridded WG will be assessed in terms of selected climatic characteristics (focusing on characteristics related to variability and extremes of surface temperature and precipitation). Acknowledgements: The present experiment is made within the frame of projects ALARO-Climate (project P209/11/2405 sponsored by the Czech Science Foundation), WG4VALUE (project LD12029 sponsored by the Ministry of Education, Youth and Sports of CR) and VALUE (COST ES 1102

  12. Long-term snow and weather observations at Weissfluhjoch and its relation to other high-altitude observatories in the Alps

    NASA Astrophysics Data System (ADS)

    Marty, Christoph; Meister, Roland

    2012-12-01

    Snow and weather observations at Weissfluhjoch were initiated in 1936, when a research team set a snow stake and started digging snow pits on a plateau located at 2,540 m asl above Davos, Switzerland. This was the beginning of what is now the longest series of daily snow depth, new snow height and bi-monthly snow water equivalent measurements from a high-altitude research station. Our investigations reveal that the snow depth at Weissfluhjoch with regard to the evolution and inter-annual variability represents a good proxy for the entire Swiss Alps. In order to set the snow and weather observations from Weissfluhjoch in a broader context, this paper also shows some comparisons with measurements from five other high-altitude observatories in the European Alps. The results show a surprisingly uniform warming of 0.8°C during the last three decades at the six investigated mountain stations. The long-term snow measurements reveal no change in mid-winter, but decreasing trends (especially since the 1980s) for the solid precipitation ratio, snow fall, snow water equivalent and snow depth during the melt season due to a strong temperature increase of 2.5°C in the spring and summer months of the last three decades.

  13. Where fast weathering creates thin regolith and slow weathering creates thick regolith

    SciTech Connect

    Bazilevskaya, Ekaterina; Lebedeva, Marina; Pavich, Milan; Rother, Gernot; Parkinson, D. Y.; Cole, David; Brantley, S. L.

    2012-01-01

    Weathering disaggregates rock into regolith the fractured or granular earthmaterial that sustains life on the continental land surface. Here, we investigate what controls the depth of regolith formed on ridges of two rock compositions with similar initial porosities in Virginia (USA).A priori, we predicted that the regolith on diabasewould be thicker than on granite because the dominant mineral (feldspar) in the diabase weathers faster than its granitic counterpart. However, weathering advanced 20deeper into the granite than the diabase. The 20-thicker regolith is attributed mainly to connected micron-sized pores, microfractures formed around oxidizing biotite at 20m depth, and the lower iron (Fe) content in the felsic rock. Such porosity allows pervasive advection and deep oxidation in the granite. These observations may explainwhy regolithworldwide is thicker on felsic compared tomafic rock under similar conditions. To understand regolith formationwill require better understanding of such deep oxidation reactions and how they impact fluid flow during weathering.

  14. Enhancing Extreme Heat Health-Related Intervention and Preparedness Activities Using Remote Sensing Analysis of Daily Surface Temperature, Surface Observation Networks and Ecmwf Reanalysis

    NASA Astrophysics Data System (ADS)

    Garcia, R. L.; Booth, J.; Hondula, D.; Ross, K. W.; Stuyvesant, A.; Alm, G.; Baghel, E.

    2015-12-01

    Extreme heat causes more human fatalities in the United States than any other natural disaster, elevating the concern of heat-related mortality. Maricopa County Arizona is known for its high heat index and its sprawling metropolitan complex which makes this region a perfect candidate for human health research. Individuals at higher risk are unequally spatially distributed, leaving the poor, homeless, non-native English speakers, elderly, and the socially isolated vulnerable to heat events. The Arizona Department