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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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NASA NTRS1988

Correlative Measurements Program

The GSFC Correlative Measurements Program at the Wallops Flight Facility was represented on the Satellite/Satellite Intercomparisons Working Group. The Correlative Measurements Program uses the Rocket Ozonesonde (ROCOZ-A) and the Electrochemical Concentration Cell (ECC) balloon borne ozonesonde to measure the vertical profile of ozone amount in the atmosphere. The balloon work is described in a separate report. The ROCOZ-A instrument was used for many years to provide in situ truth data for various satellite ozone measuring systems, such as SBUV on Nimbus-7, SAGE-II, SBUV-II on the NOAA series of polar orbiting satellites, SME, LIMS, etc. The particular data sets of interest to the Ozone Trends Panel Working Group were collected at Natal, Brazil. The major results produced for and used by the Ozone Trends Panel are shown. The ROCOZ-A average ozone density profile is plotted versus altitude on the left. ECC ozonesondes were used for the portion of the profile below 20 km, the lower limit for ROCOZ-A. The difference between SAGE-II and ROCOZ-A average density profiles is shown.

Parsons, C. L.↗
NASA NTRS1988

Ozone measurements using balloon-borne ozonesondes

Vertical profiles of atmospheric ozone have been measured for a number of years by WFF personnel using small balloon borne ozonesondes. These sondes are interfaced with meteorological radiosondes so that both ozone data and meterological data (pressure, temperature, humidity, wind speed and direction) are obtained from ground level up to 30 to 35 km. Efforts at Wallops have been focused in three areas. The first involves biweekly launches from two sites (Wallops and Natal, Brazil), timed to coincide with overpasses of satellite borne ozone sensors such as the Solar Backscattered Ultraviolet. The resulting data are reported to the World Ozone Data Center and are used for satellite correlative support, as well as, for studies of both tropospheric and stratospheric ozone. The second activity consists of field campaigns in remote locations in support of special projects. The third is a continuing activity to quantitatively evaluate and improve the sonde's performance under stratospheric conditions.

Torres, A. L.↗
NASA NTRS1989

Comparison of satellite-inferred (SAGE II) aerosol optical depths with corresponding airborne sunphotometer optical depths

Solar radiation measurements were made with an airborne multiwavelength autotracking sunphotometer detector off the northeastern coast of Brazil on April 6, 1985. These measurements are used to validate solar radiation measurements from the Stratospheric Aerosol and Gas Experiment (SAGE II). The SAGE II data below 17.5 km are dominated by attenuation due to thunderstorm-generated cirrus clouds. When integrated above 17.5 km, however, the aerosol extinction profiles from SAGE II yield aerosol optical depths that are consistent with the corresponding sunphotometer values above 10.1 km.

Livingston, John M.↗
NASA NTRS1988

Improved ground hydrology calculations for global climate models (GCMs) - Soil water movement and evapotranspiration

A physically based ground hydrology model is presented that includes the processes of transpiration, evaporation from intercepted precipitation and dew, evaporation from bare soil, infiltration, soil water flow, and runoff. Data from the Goddard Institute for Space Studies GCM were used as inputs for off-line tests of the model in four 8 x 10 deg regions, including Brazil, Sahel, Sahara, and India. Soil and vegetation input parameters were caculated as area-weighted means over the 8 x 10 deg gridbox; the resulting hydrological quantities were compared to ground hydrology model calculations performed on the 1 x 1 deg cells which comprise the 8 x 10 deg gridbox. Results show that the compositing procedure worked well except in the Sahel, where low soil water levels and a heterogeneous land surface produce high variability in hydrological quantities; for that region, a resolution better than 8 x 10 deg is needed.

Abramopoulos, F.↗
NASA NTRS1989

Retrieval of aerosol size distribution moments from multiwavelength particulate extinction measurements

Two methods for inferring aerosol size distribution moments from multiwavelength particulate extinction measurements are studied. The methods are an eigenvalue technique that approximates an appropriate moment-weighting function by a linear combination of kernel functions and a conversion ratio approach that uses the ratio of the particulate extinction measurements at two wavelengths to choose a model moment-to-extinction conversion ratio. The techniques are applied to infer the third moment, or volume, of the aerosol size distribution from actual particulate extinction measurements taken as part of the Stratospheric Aerosol and Gas Experiment II during a correlative measurement experiment in Brazil in April 1985.

Livingston, John M.↗
NASA NTRS1989

Validation of SAGE II ozone measurements

Five ozone profiles from the Stratospheric Aerosol and Gas Experiment (SAGE) II are compared with coincident ozonesonde measurements obtained at Natal, Brazil, and Wallops Island, Virginia. It is shown that the mean difference between all of the measurements is about 1 percent and that the agreement is within 7 percent at altitudes between 20 and 53 km. Good agreement is also found for ozone mixing ratios on pressure surfaces. It is concluded that the SAGE II profiles provide useful ozone information up to about 60 km altitude.

Cunnold, D. M.↗
NASA NTRS1989

Shade images of forested areas obtained from LANDSAT MSS data

The pixel size in the present day Remote Sensing systems is large enough to include different types of land cover. Depending upon the target area, several components may be present within the pixel. In forested areas, generally, three main components are present: tree canopy, soil (understory), and shadow. The objective is to generate a shade (shadow) image of forested areas from multispectral measurements of LANDSAT MSS (Multispectral Scanner) data by implementing a linear mixing model, where shadow is considered as one of the primary components in a pixel. The shade images are related to the observed variation in forest structure, i.e., the proportion of inferred shadow in a pixel is related to different forest ages, forest types, and tree crown cover. The Constrained Least Squares (CLS) method is used to generate shade images for forest of eucalyptus and vegetation of cerrado using LANDSAT MSS imagery over Itapeva study area in Brazil. The resulted shade images may explain the difference on ages for forest of eucalyptus and the difference on three crown cover for vegetation of cerrado.

Shimabukuro, Yosio Edemir↗
NASA NTRS1989

Remote sensing of biomass burning in the tropics

A technique for assessing the effects of biomass burning on the climate is described. This method is based on the analysis of remote sensing data for the emitted particulates. The relationship between particulates and trace gases is studied. The assessment technique is applied to the 1987 burning season in Brazil. It is noted that during the dry season there may be up to 5000 fires per day which emit 200 ton/hr CO2, 20 ton/hr CO, and 0.5 ton/hr of CH4 to the atmosphere.

Kaufman, Yoram J.↗
NASA NTRS1990

The Amazon Boundary-Layer Experiment (ABLE 2B) - A meteorological perspective

The Amazon Boundary-Layer Experiments (ABLE) 2A and 2B, which were performed near Manaus, Brazil in July-August, 1985, and April-May, 1987 are discussed. The experiments were performed to study the sources, sinks, concentrations, and transports of trace gases and aerosols in rain forest soils, wetlands, and vegetation. Consideration is given the design and preliminary results of the experiment, focusing on the relationships between meteorological scales of motion and the flux, transports, and reactions of chemical species and aerosols embedded in the atmospheric fluid. Meteorological results are presented and the role of the meteorological results in the atmospheric chemistry experiment is examined.

Garstang, Michael↗
NASA NTRS1989

Shade images of forested areas obtained from Landsat MSS data

The objective of this report is to generate a shade (shadow) image of forested areas from Landsat MSS data by implementing a linear mixing model, where shadow is considered as one of the primary components in a pixel. The shade images are related to the observed variation in forest structure; i.e., the proportion of inferred shadow in a pixel is related to different forest ages, forest types, and tree crown cover. The constrained least-squares method is used to generate shade images for forest of eucalyptus and vegetation of 'cerrado' over the Itapeva study area in Brazil. The resulted shade images may explain the difference on ages for forest of eucalyptus and the difference on tree crown cover for vegetation of cerrado.

Shimabukuro, Yosio Edemir↗
NASA NTRS1990

Measurements of reactive nitrogen oxides (NO/y/) within and above a tropical forest canopy in the wet season

Measurements of ambient concentrations of reactive nitrogen oxides were made in the Amazon rain forest, near Manaus, Brazil, continuously at 39 m (above the canopy), and on several days and nights at 19 m (within the canopy). Concentrations were very low, typically 100-700 pptv, except for brief periods when up to 5000 pptv of NO(y) was observed, indicating polluted air from the urban area of Manaus. The forest was a net sink for NO(y) with the NO(y) flux = -7.6 + or - 5.0) x 10 to the 9th molecules/sq cm per sec in unpolluted periods, even though soils emitted NO at a significant rate (8.9 + or - 1.5 x 10 to the 9th molecules/sq cm per sec). The deposition rate for NO(y) appeared to be much larger during the daytime than at night, suggesting that uptake was controlled either by plant processes (stomatal opening) or by supply of reactive components of NO(y) (e.g., HNO3) during the daytime. Implications for regional and global atmospheric chemistry are discussed.

Bakwin, Peter S.↗
NASA NTRS1990

Sources of variation in nitrous oxide flux from Amazonian ecosystems

Nitrous oxide flux and soil nutrient characteristics were measured in three undisturbed tropical ecosystem types, in cleared and burned areas, and in areas of forest converted to pasture near Manaus, Brazil. Nitrogen mineralization, nitrification, and soil nitrogen pools were high in upland forests on clay soils (terra firme) and low in the sand-type and floodplain (varzea) soils. Nitrous oxide flux followed the same pattern, with an average flux of 1.9 ng/sq cm per hr in terra firme, 0.3 in sand types, and 0.1 in varzea. Flux from recently cleared and burned areas did not differ from terra firme forest, but pastures had significantly elevated fluxes (10.3 ng/sq cm per hr). These data were combined with satellite data-based areal estimates of land cover classes to estimate total N2O-N flux from the intensive study area used by the Amazon Boundary Layer Experiment. Total N2O-N flux from the area was 22.9 kg/h; pastures covered 11 percent of the area but accounted for over 40 percent of the flux.

Matson, P. A.↗
NASA NTRS1990

Airborne flux measurements and budget estimates of trace species over the Amazon Basin during the GTE/ABLE 2B expedition

In situ airborne measurements of turbulent heat, moisture, momentum, ozone, and carbon monoxide fluxes in a convective boundary layer were obtained over a tropical rain forest between 1100 and 1630 LT on May 4, 1987. The aircraft flight path was chosen so as to fly over the tower site at the Ducke Forest Reserve near Manaus, Amazonas, Brazil. Both turbulence statistics and mean quantities were used to study the budgets of heat, water vapor, ozone, and carbon monoxide. The ozone budget study shows an accumulation rate in the boundary layer of 0.3 + or - 0.2 ppbv/h. The surface resistance to ozone during this flight was determined to be 0.06 + or - 0.03 s/cm, while the aerodynamic resistance was 0.14-0.17 s/cm. Results from the CO budget analysis show a midday accumulation rate of 0.6 + or - 0.3 ppbv/h in the Amazonian boundary layer. The evidence suggests production of CO in the PBL. A source of CO may exist below the lowest flight level (about 150 m), although it was not possible to determine what part of the flux at flight level was due to chemical production and what part may be due to surface emission.

Ritter, John A.↗
NASA NTRS1990

Ozone and aerosol distributions over the Amazon Basin during the wet season

Results are presented of O3 and aerosol measurements made in the lower troposphere from April 13 through May 10, 1987, as part of the wet season field experiment. Aircraft flights on the NASA Electra were conducted in the vicinity of Manaus, Brazil and between Manaus and the mouth of the Amazon River. Airborne O3 measurements were made in situ and with a lidar system pointed below the aircraft in nadir mode of operation. Data collection and results concerning the distributions of O3 and aerosols observed during the wet season from within the mixed layer to the middle troposphere over the central Amazon basin and between Manaus and Belem are discussed, and these observations are compared to the measurements obtained in the 1985 dry season. Ozone mixing ratio values are found to be lower than those of the 1985 dry season by 6-8 ppbv, indicating a strong removal process near the surface during wet season. It is also found that within the mixed layer O3 levels appeared to be lower over the forest compared to over the ocean.

Browell, Edward V.↗
NASA NTRS1990

Carbon monoxide over the Amazon Basin during the wet season

Measurements of the distribution of carbon monoxide in the lower atmosphere (150-5000 m) over the Amazon region of Brazil during the wet season, taken in conjunction with the 1987 NASA Global Tropospheric Experiment/Amazon Boundary Layer Experiment (ABLE 2B), are analyzed. About 100 hr of airborne, in situ CO measurements were obtained using a tunable diode laser system, providing insights into factors influencing the basin-scale distribution of CO in the Amazonian troposphere during wet season conditions. Distribution of CO over the altitudes 0.15-4.5 km was influenced by such factors as surface emissions from biological sources and long-range transport of pollutants from Northern Hemisphere sources. It is noted that the disruption of mixed layer growth and decay processes has a particularly important influence on CO concentration in the daytime lower troposphere and that the correlation of CO with O3 was positive under conditions influenced by Northern Hemisphere air and negative under all other conditions observed.

Harriss, R. C.↗
NASA NTRS1990

Aerosol chemistry during the wet season in central Amazonia - The influence of long-range transport

The temporal variation in the concentration and chemistry of the atmospheric aerosol over central Amazonia, Brazil, during the 1987 wet season is discussed based on ground and aircraft collected data obtained during the NASA GTE ABLE 2B expedition conducted in April/May 1987. It is found that wet-season aerosol concentrations and composition are variable in contrast to the more uniform biogenic aerosol observed during the 1985 dry season; four distinct intervals of enhanced aerosol concentration coincided with short periods (3 to 5 d) of extensive rainfall. It is hypothesized that aerosol chemistry in Amazonia during the wet season is strongly influenced by long-range transport of soil dust, marine aerosol, and possibly biomass combustion products advected into the central Basin by large-scale tropospheric circulation, producing periodic pulses of material input to local boundary layer air. The resultant wet-season aerosol regime is dynamic, in contrast to the uniformity of natural biogenic aerosols during the dry season.

Talbot, R. W.↗
NASA NTRS1990

Rainfall and surface kinematic conditions over central amazonia during ABLE 2B

Rainfall, rainfall systems, and surface kinematics of the central Amazon basin wet season are investigated using meteorological and chemical data collected during the wet season Amazon Boundary Layer Experiment (ABLE) near Manaus, Brazil. Through analysis of (GOES-West) imagery, it is determined that, based on location of the initial development, there are three main types of convective systems which influence a mesoscale network near Manaus, namely the Coastal Occurring Systems (COS), the Basin Occurring Systems (BOS), and the Locally Occurring Systems (LOS). Chemical analysis of rainwater delivered by these systems shows significant differences in concentrations of formate, acetate, pyruvate, sulfate, and hydrogen ion, and measurements of aerosol concentrations near Manaus show large influxes of aerosols into central Amazonia after passage of BOS and COS. Results of satellite based classification of the rain-producing systems are discussed.

Greco, Steven↗
NASA NTRS1990

Radio emission in peculiar galaxies

During the last decades a number of surveys of peculiar galaxies have been carried out and accurate positions become available. Since peculiarities are a possible evidence of radio emission (Wright, 1974; Sulentic, 1976; Stocke et al., 1978), the authors selected a sample of 24 peculiar galaxies with optical jet-like features or extensions in different optical catalogues, mainly the Catalogue of Southern Peculiar Galaxies and Associations (Arp and Madore, 1987) and the ESO/Uppsala Survey of the ESO(B) Atlas (Lauberts, 1982) for observation at the radio continuum frequency of 22 GHz. The sample is listed in a table. Sol (1987) studied this sample and concluded that the majority of the jet-like features seem to admit an explanation in terms of interactive galaxies with bridges and/or tails due to tidal effects. Only in a few cases do the jets seem to be possibly linked to some nuclear activity of the host galaxy. The observations were made with the 13.7m-radome enclosed Itapetinga Radiotelescope (HPBW of 4.3 arcmin), in Brazil. The receiver was a 1 GHz d.s.b. super-heterodine mixer operated in total-power mode, with a system temperature of approximately 800 K. The observational technique consisted in scans in right ascention, centralized in the optical position of the galaxy. The amplitude of one scan was 43 arcmin, and its duration time was 20 seconds. The integration time was at least 2 hours (12 ten-minute observations) and the sensibility limit adopted was an antenna temperature greater than 3 times the r.m.s. error of the baseline determination. Virgo A was used as the calibrator source. Three galaxies were detected for the first time as radio sources and four other known galaxies at low frequencies had their flux densities measured at 22 GHz. The results for these sources are presented.

Demellorabaca, Dulia F.↗