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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1984

Early season spring small grains proportion estimation

An accurate, automated method for estimating early season spring small grains from Landsat MSS data is discussed. The method is summarized and the results of its application to 100 sample segment-years of data from the US Northern Great Plains in 1976, 1977, 1978, and 1979 are summarized. The results show that this estimator provides accurate estimates earlier in the growing season than previous methods. Ground truth is required only in the estimator development, and data storage, transmission, preprocessing, and processing requirements are minimal.

Phinney, D. E.↗
NASA NTRS1990

Measurement of atmospheric opacity at 278 GHz at McMurdo Station, Antarctica in austral spring seasons, 1986 and 1987

A quasi-continuous record is presented of atmospheric opacity measured at 278 GHz (1.1 mm wavelength) from the McMurdo Station (Antarctica) during austral spring seasons of 1986 (August 30 - October 30) and 1987 (September 4 - October 13) with measurements taken every 20 minutes (except during storms or other periods of high opacity). All data are reduced to represent opacity in the zenith direction. It was found that, during much of September, the two successive years differed considerably in tropospheric opacity. In 1986, water vapor and attendant opacity were generally lower, due to low tropospheric temperatures. Measured opacities were found to be higher than would be expected from the empirical relationships representing opacity as a function of water vapor column density at mm-wavelengths, as proposed by Rice and Ade (1979), Zammit and Ade (1981), and Liebe (1985).

De Zafra, R. L.↗
NASA NTRS1983

Early season spring small grains direct proportion estimation - Development and evaluation of a Landsat based methodology

The Inventory Technology Development (ITD) project of the Agriculture and Resources Inventory Surveys Through Aerospace Remote Sensing (AgRISTARS) program has developed an accurate, automated technology for early season estimation of spring small grains areal proportion from Landsat MSS data. The design criteria for an early season procedure included estimates available within the first 30 days of the growing season, low data processing/preprocessing requirements and no need for scene-to-scene registration. The prototype estimator which meets the design goals is based on a constrained linear model in which the observed spectral response of an entire scene is modeled as a linear combination of the major constituent elements in the scene. The procedure was evaluated over 100 sample segments collected for crop years 1976 through 1979 in the U.S. Northern Great Plains. Analysis of the test results indicated accuracy that compare favorably with both the automated at-harvest technologies tested during the FY81-82 AgRISTARS Spring Small Grains Pilot experiments and earlier analyst-intensive at-harvest technologies.

Phinney, D. E.↗
NASA NTRS2019

Dynamics and Variability of the Spring Dry Season in the United States Southwest as Observed in AmeriFlux and NLDAS-2 Data

The spring dry season occurring in an arid region of the Southwest United States, which receives both winter storm track and summer monsoon precipitation, is investigated. Bimodal precipitation and vegetation growth provide an opportunity to assess multiple climate mechanisms and their impact on hydroclimate and ecosystems.We detect multiple shifts from wet to drier conditions in the observational record and land surface model output. Focusing on the recent dry period, a shift in the late 1990s resulted in earlier and greater spring soil moisture draw down, and later and reduced spring vegetation green-up, compared to a prior wet period (1979 - 1997). A simple soil moisture balance model shows this shift is driven by changes in winter precipitation.The recent post-1999 dry period, as well as an earlier one from 1948 - 1966, are both related to the cool tropics phase of Pacific decadal variability which influences winter precipitation. In agreement with other studies for the Southwest United States, we find the recent drought cannot be explained in terms of precipitation alone, but also is due to the rising influence of temperature, thus highlighting the sensitivity of this region to warming temperatures. Future changes in the spring dry season will therefore be affected by how tropical decadal variability evolves, and also by emerging trends due to human-driven warming.

Pascolini-Campbell, Madeleine↗
NASA NTRS1977

Preliminary report on the CTS transient event counter performance through the 1976 spring eclipse season

The transient event counter is described, defining its operational characteristics, and presenting the preliminary results obtained through the first 90 days of operation including the Spring 1976 eclipse season. The results show that the CTS was charged to the point where discharges have occurred. The discharge induced transients have not caused any anomalous events in spacecraft operation. The data indicate that discharges can occur at any time during the day without preference to any local time quadrant. The number of discharges occurring in the 1 sec sample interval are greater than anticipated.

Stevens, N. J.↗
NASA NTRS1976

Preliminary report on the CTS transient event counter performance through the 1976 spring eclipse season

The transient event counter (TEC), senses and counts transients having a voltage rise of greater than five volts in three separate wire harnesses: the attitude control harness, the solar array instrumentation harness and the solar array power harness. The operational characteristics of TEC are defined and the preliminary results obtained through the first 90 days of operation including the spring 1976 eclipse season are presented. The results show that the Communications Technology Satellite was charged to the point where discharges occurred. The discharge induced transients did not cause any anomalous events in spacecraft operation. The data indicate that discharges can occur at any time during the day without preference to any local time quadrant. The number of discharges occurring in the one second sample interval are greater than anticipated. The compilation and review of the data is continuing.

Stevens, N. J.↗
NASA NTRS2013

Examining Lake Michigan Spring Euphotic Depth (Zeu) Anomalies: Utilizing 10 Years of MODIS-Aqua Data at 4 Kilometer Resolution

Examination of ten years of euphotic depth anomalies in Lake Michigan during the months of March-June indicates the following: The well-known and frequently observed occurrence of a turbidity feature in the southern part of Lake Michigan during the spring season has become less common during the period 2003-2012. Overall, the clarity of Lake Michigan water in the southern end of the lake appears to have increased spring season over the period 2003-2012. Euphotic depth can be used as a primary indicator of changes in Lake Michigan lacustrine optics, and for other large lakes. Unique events, such as the heavy rains in June 2008, can have a distinct signature in the euphotic depth anomaly distribution in Lake Michigan.

Acker, James G.↗
NASA NTRS1994

Seasonal trend analysis of published ground-based and TOMS total ozone data through 1991

A seasonal trend analysis of published Dobson (including stations' newly revised and Brewer-simulated Dobson) total ozone data through 1991 from a network of 56 stations has been performed, using three different data periods. The trend results for the longest data period 1964 - 1991 indicate substantial negative trends in ozone in the higher northern latitudes during the winter and spring seasons, some evidence of negative trend in the higher southern latitudes (30 deg S - 55 deg S) during all seasons, and trends close to zero for all seasons over the 30 deg S - 30 deg N latitude range. For the shortest data period, November 1978 through 1991, there is a clear indication that trends have become more negative in the higher northern latitudes, especially during the winter and spring seasons, and also in the higher southern latitudes in all seasons. A seasonal trend analysis of zonal averages of total ozone mapping spectrometer (TOMS) satellite total ozone data for the comparable period November 1978 through 1991 has also been performed, and moderately good agreement is found between trends in Dobson and TOMS data over this period.

Reinsel, Gregory C.↗
NASA NTRS1980

Aerial color infrared photography applications to citriculture

Results of a one-year experimental study on the use of aerial color infrared photography in citrus grove management are presented. It is found that the spring season, when trees are in flush (have young leaves), is the best season to photograph visible differences between healthy and diseased trees. It is also shown that the best photography can be obtained with a 12-in. focal length lens. The photographic scale that allowed good photo interpretation with simple inexpensive equipment was 1 in. = 330 ft. The use of a window-overlay transparency method allowed rapid photo interpretation and data recording in computer-compatible forms. Aerial color infrared photography carried out during the spring season revealed a more accurate status of tree condition than visual inspection.

Blazquez, C. H.↗
NASA NTRS1990

The role of the seasonal cycle in the quasi-biennial oscillation of ozone

The evidence for seasonal synchronization of the ozone quasi-biennial oscillation (QBO) is reviewed, showing how this behavior is not expected on the basis of QBO transport alone but may arise due to the seasonal cycle. Near the equator, the ozone QBO is closely tied to the dynamical QBO and exhibits the same period as that oscillation. Maximum column ozone is attained soon after the transition to westerlies at 50 mb. In the subtropics, the ozone QBO is strongly tied to the seasonal cycle, with anomalies centered in the winter-spring season irrespective of QBO phase. These anomalies result from the interaction of the annual cycle and the QBO. Numerical model results are reported which establish that hemispheric asymmetry in the ozone QBO does not require seasonal asymmetries in the strength or location of the Hadley circulation. The fundamental cause of hemispheric asymmetry in the subtropical ozone QBO is the timing of equatorial, ozone anomalies relative to the seasonal cycle.

Gray, Lesley J.↗
NASA NTRS1987

Satellite-derived attributes of cloud vortex systems and their application to climate studies

Defense Meteorological Satellite Program (DMSP) visible and infrared mosaics are analyzed in conjunction with synoptic meteorological observations of sea level pressure (SLP) and upper-air height to derive composite patterns of cyclonic cloud vortices for the Northern Hemisphere. The patterns reveal variations in the structure and implied dynamics of cyclonic systems at different stages of development that include: (1) increasing vertical symmetry of the lower-level and upper-air circulations and (2) decreasing lower-tropospheric thicknesses and temperature advection, associated with increasing age of the vortex. Cloud vortices are more intense in winter than in summer and typically reach maximum intensity in the short-lived prespiral signature stage. There are major structural differences among frontal wave, polar air, and 'instant occlusion' cyclogenesis types. Cyclones in the dissipation stage may reintensify (deepen), as denoted by the appearance in the imagery of an asymmetric cloud band or a tightened spiral vortex. The satellite-derived statistics on cloud vortex intensity, which are seasonal- and latitude- as well as type-dependent, are applied to a preliminary examination of the synoptic manifestations of seasonal climate variability. An apparently close relationship is found, for two winter and spring seasons, between Northern Hemisphere cyclonic activity and variations in cryosphere variables, particularly the extent of Arctic sea ice. The results may indicate that increased snow and ice extent accompany a southward displacement of cyclonic activity and/or a predominance of deeper systems. However, there is also a strong regional dependence to the ice-synoptics feedback. This study demonstrates the utility of high resolution meteorological satellite imagery for studies of climate variations (climate dynamics).

Carleton, Andrew M.↗
NASA NTRS2013

Juniper Pollen Hotspots in the Southwest

Rationale: Juniperus pollen is a major allergen in Texas, Oklahoma, and New Mexico. While the bulk of pollen may be released in rural areas, large amounts of pollen can be transported to urban areas. Major juniper species in the region include: Juniperus ashei, J. virginiana, J. pinchotii, and J. monosperma. Pollen release is virtually continuous beginning in late September with J. pinchotii and ending in May with J. monosperma. Urban areas in the region were evaluated for the potential of overlapping seasons in order to inform sensitive individuals. Methods: Burkard volumetric pollen traps were established for two consecutive spring seasons at 6 sites in northern New Mexico and 6 sites for two consecutive winter and fall seasons in Texas and Oklahoma Standard methods were used in the preparation and analysis of slides. Results: The Dallas-Fort Worth Metroplex is home to over 6 million people. It is adjacent to populations of J. pinchotii, J. virginiana, and J. ashei. Peak concentration near Dallas for J. ashei in 2011 was 5891 pollen grains/m3 in January 7th. The peak date for J. pinchotii at an upwind sampling location in San Marcos, TX was November 1, 2010 and peak for J. virginiana at a nearby station in Tulsa, OK was November 1, 2010 and peak for J. virginiana at a nearby station in Tulsa, OK was February 20, 2011. Amarillo, TX is adjacent to J. pinchotii, J. ashei, and J. monosperma populations and may be subject to juniper pollen from September through May. Conclusions: Considering the overlapping distributions of juniper trees and the overlapping temporal release of pollen, sensitive patients may benefit from avoiding hotspots.

Bunderson, L. D.↗
NASA NTRS1988

Visible and near-ultraviolet spectroscopy at Thule AFB (76.5 N) from January 28 - February 15, 1988

Near-ultraviolet and visible spectrographs identical to those employed at McMurdo Station, Antarctica (77.8 S) during the austral spring seasons of 1986 and 1987 were used to study the stratosphere above Thule, Greenland (76.5 N) during early spring, 1988. Observations were carried out both at night using the direct moon as a light source, and during the day by collecting the scattered light from the zenith sky when solar zenith angles were less than about 94.5 degrees. Excellent meteorological conditions prevailed in the troposphere and stratosphere at Thule. Surface weather was extremely clear over most of the period, facilitating measurements of the direct light from the moon. The lower stratospheric arctic polar vortex was located very near Thule throughout the observing period, and temperature at the 30 mbar level were typically below -80 C above Thule, according to the National Meteorological Center daily analyses. Thus conditions were favorable for polar stratospheric cloud formation above Thule. Total column ozone abundances were about 350 to 400 Dobson units, and did not suggest a clear temporal trend over the observing period. Stratospheric nitrogen dioxide measurements were complicated by the presence of a large component of tropospheric pollution on many occasions. Stratospheric nitrogen dioxide could be identified on most days using the absorption in the scattered light from the zenith sky, which greatly enhances the stratospheric airmass while suppressing the tropospheric contribution. These measurements suggest that the total vertical column abundance of nitrogen dioxide present over Thule in February was extremely low, sometimes as low as 3 x 10 to the 14th per sq cm. The abundance of nitrogen dioxide increased systemically from about 3 x 10 to the 14th in late January to 1.0 x 10 to the 15th per sq cm in mid-February, perhaps because of photolysis of N2O5 in the upper part of the stratosphere, near 25 to 35 km.

Mount, G. H.↗
NASA NTRS2008

Seasonal Trends in Stratospheric Water Vapor as Derived from SAGE II Data

Published analysis of HALOE and Boulder balloon measurements of water vapor have shown conflicting trends in stratospheric water vapor for the periods of 1981 through 2005. Analysis of the SAGE II monthly mean water vapor data filtered for large aerosol events for time periods from 1985-1991, 1995-1999, and 2000-2005 have shown a globally decreasing water vapor trend at 17.5km. Seasonal analysis for these three time periods show a decreasing trend in water vapor at 17.5km for the winter and spring seasons. The summer and autumn seasonal analysis show a decreasing trend from 1985-2005, however, there is a increasing trend in water vapor at 17.5km for these seasons during 1995-2005. Latitude vs height seasonal analysis show a decreasing trend in the lower stratosphere between 20S - 20N for the autumn season, while at the latitudes of 30-50S and 30-50N there is an increasing trend in water vapor at heights up to 15km for that season. Comparison with regions of monsoon activity (Asian and North American) show that the Asian monsoon region had some effect on the lower stratospheric moistening in 1995-1999, however, for the time period of 2000-2005, there was no change in the global trend analysis due to either monsoon region. This may be due to the limitations of the SAGE II data from 2000-2005.

Roell, Marilee M.↗
NASA NTRS2022

Cause of a Lower-Tropospheric High-Ozone Layer in Spring Over Hanoi

The ozonesonde observations in Hanoi, Vietnam, over fourteen years since 2004 have confirmed the enhancement in lower tropospheric ozone concentration at about 3 km altitude in the spring season. We investigated the evolution of the ozone enhancement from analysis of meteorological data, backward trajectories, and model sensitivity experiments. In spring, air masses over Hanoi exhibit strong height dependence. At 3km, the high-ozone air masses originate from the land area to the west of Hanoi, while low-ozone air masses below about 1.5 km are from the oceanic area to the east. Above 4 km, the air masses are mostly traced back to the farther west area. The chemical transport model simulations revealed that precursor emissions from biomass burning in the inland Indochina Peninsula have the largest contribution to the lower tropospheric ozone enhancement, which is transported upward and eastward and overhangs the clean air intrusion from the ocean to the east of Hanoi. At this height level, the polluted air has the horizontal extent of about 20 degrees in longitude and latitude. The polluted air observed in Hanoi is transported further east and widely spread over the northern Pacific Ocean.

tropospheric ozone↗
NASA NTRS2022

Cause of a Lower-Tropospheric High-Ozone Layer in Spring Over Hanoi

The ozonesonde observations in Hanoi, Vietnam, over fourteen years since 2004 have confirmed the enhancement in lower tropospheric ozone concentration at about 3 km altitude in the spring season. We investigated the evolution of the ozone enhancement from analysis of meteorological data, backward trajectories, and model sensitivity experiments. In spring, air masses over Hanoi exhibit strong height dependence. At 3km, the high-ozone air masses originate from the land area to the west of Hanoi, while low-ozone air masses below about 1.5 km are from the oceanic area to the east. Above 4 km, the air masses are mostly traced back to the farther west area. The chemical transport model simulations revealed that precursor emissions from biomass burning in the inland Indochina Peninsula have the largest contribution to the lower tropospheric ozone enhancement, which is transported upward and eastward and overhangs the clean air intrusion from the ocean to the east of Hanoi. At this height level, the polluted air has the horizontal extent of about 20 degrees in longitude and latitude. The polluted air observed in Hanoi is transported further east and widely spread over the northern Pacific Ocean.

Hanoi↗
NASA NTRS2015

High-Resolution Mesoscale Model Setup for the Eastern Range and Wallops Flight Facility

Mesoscale weather conditions can have an adverse effect on space launch, landing, ground processing, and weather advisories, watches, and warnings at the Eastern Range (ER) in Florida and Wallops Flight Facility (WFF) in Virginia. During summer, land-sea interactions across Kennedy Space Center (KSC) and Cape Canaveral Air Force Station (CCAFS) lead to sea breeze front formation, which can spawn deep convection that can hinder operations and endanger personnel and resources. Many other weak locally-driven low-level boundaries and their interactions with the sea breeze front and each other can also initiate deep convection in the KSC/CCAFS area. These convective processes often last 60 minutes or less and pose a significant challenge to the local forecasters. Surface winds during the transition seasons (spring and fall) pose the most difficulties for the forecasters at WFF. They also encounter problems forecasting convective activity and temperature during those seasons. Therefore, accurate mesoscale model forecasts are needed to better forecast a variety of unique weather phenomena. Global and national scale models cannot properly resolve important local-scale weather features at each location due to their horizontal resolutions being much too coarse. Therefore, a properly tuned local data assimilation (DA) and forecast model at a high resolution is needed to provide improved capability. To accomplish this, a number of sensitivity tests were performed using the Weather Research and Forecasting (WRF) model in order to determine the best DA/model configuration for operational use at each of the space launch ranges to best predict winds, precipitation, and temperature. A set of Perl scripts to run the Gridpoint Statistical Interpolation (GSI)/WRF in real-time were provided by NASA's Short-term Prediction Research and Transition Center (SPoRT). The GSI can analyze many types of observational data including satellite, radar, and conventional data. The GSI/WRF scripts use a cycled GSI system similar to the operational North American Mesoscale (NAM) model. The scripts run a 12-hour pre-cycle in which data are assimilated from 12 hours prior up to the model initialization time. A number of different model configurations were tested for both the ER and WFF by varying the horizontal resolution on which the data assimilation was done. Three different grid configurations were run for the ER and two configurations were run for WFF for archive cases from 27 Aug 2013 through 10 Nov 2013. To quantify model performance, standard model output will be compared to the Meteorological Assimilation Data Ingest System (MADIS) data. The MADIS observation data will be compared to the WRF forecasts using the Model Evaluation Tools (MET) verification package. In addition, the National Centers for Environmental Prediction's Stage IV precipitation data will be used to validate the WRF precipitation forecasts. The author will summarize the relative skill of the various WRF configurations and how each configuration behaves relative to the others, as well as determine the best model configuration for each space launch range.

Watson, Leela R.↗