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At least 1,225 records · Page 68
All sourcesNASA NTRSDOE OSTI
NASA NTRS2003

Validation of the Measurement of Pollution in the Troposphere (MOPITT) Experiment by Ground-Based Infrared Solar Spectroscopic Measurements of Carbon Monoxide (CO) and Methane (CH4)

The goal of the MOPITT experiment is to enhance our knowledge of the lower atmosphere system and particularly how it interacts with the surface/ocean/biomass systems. The particular focus is the distribution, transport, sources and sinks of carbon monoxide and methane in the troposphere. The MOPITT instrument was launched on EOS TERRA satellite December 18, 1999. After the launch and until March 22, 2000 the MOPITT instrument was in engineering and calibration mode. Beginning March 23, 2000 through May 6, 2001 the instrument was in a science measurement mode with some calibration breaks. On May 7, 2001 a criocooler on a side B died and channels 1 - 4 became inoperational. The MOPITT resumed its scientific measurements on August 25, 2001 with channels 5 - 8. With some calibration breaks the instrument currently provides the data. The project has three elements to it: hardware, data analysis and modeling. The MOPITT instrument, on the NASA EOS Terra satellite, measures the upwelling infrared radiance. Using the technique of correlation spectroscopy, information regarding the distribution of atmospheric CO and CH4 can be extracted. By using appropriate data analysis techniques, concentration profiles of CO are currently obtained on a global basis at a reasonably high horizontal (approximately 22km) and vertical resolution (approximately 3km). Column amounts of methane will be derived over the sunlit side of the orbit. These profiles are assimilated into models to study the chemistry and dynamics of CO, CH4 and other constituents of the lower atmosphere.

Pougatchev, Nikita↗
NASA NTRS2003

Electrodeposition of High Quality Nickel Phosphorous Alloys for Pollution Reduction and Energy Conservation

NASA and the University of Alabama in Huntsville have developed ecologically friendly, versatile nickel and nickel cobalt phosphorous electroplating processes. Solutions show excellent performance with high efficiency for vastly extended throughput. Properties include, clean, low temperature operation (40 - 60 C), high Faradaic efficiency, low stress and high hardness. A variety of alloy and plating speed options are easily achieved from the same chemistry using soluble anodes for metal replacement with only 25% of the phosphorous additions required for electroless nickel. Thick deposits are easily achieved unattended, for electroforming freestanding shapes without buildup of excess orthophosphate or stripping of equipment.

Engelhaupt, Darell↗
NASA NTRS2004

Electrodeposition of High Quality Nickel Phosphorous Alloys for Pollution Reduction and Energy Conservation

NASA and the University of Alabama in Huntsville have developed ecologically friendly, versatile nickel and nickel cobalt phosphorous electroplating processes. Solutions show excellent performance with high efficiency for vastly extended throughput. Properties include, clean, low temperature operation (40 - 60 C), high Faradaic efficiency, low stress and high hardness. A variety of alloy and plating speed options are easily achieved from the same chemistry using soluble anodes for metal replacement with only 25% of the phosphorous additions required for electroless nickel. Thick deposits are easily achieved unattended, for electroforming freestanding shapes without buildup of excess orthophosphate or stripping of equipment.

Engelhaupt, Darell↗
NASA NTRS2004

Application of MODIS-Derived Active Fire Radiative Energy to Fire Disaster and Smoke Pollution Monitoring

The radiative energy emitted by large fires and the corresponding smoke aerosol loading are simultaneously measured from the MODIS sensor from both the Terra and Aqua satellites. Quantitative relationships between the rates of emission of fire radiative energy and smoke are being developed for different fire-prone regions of the globe. Preliminary results are presented. When fully developed, the system will enable the use of MODIS direct broadcast fire data for near real-time monitoring of fire strength and smoke emission as well as forecasting of fire progression and smoke dispersion, several hours to a few days in advance.

Ichoku, Charles↗
NASA NTRS1991

Portable x-ray fluorescence spectrometer for environmental monitoring of inorganic pollutants

A portable x-ray fluorescence spectrometer has a portable sensor unit containing a battery, a high voltage power supply, an x-ray tube which produces a beam x-ray radiation directed toward a target sample, and a detector for fluorescent x-rays produced by the sample. If a silicon-lithium detector is used, the sensor unit also contains either a thermoelectric or thermochemical cooler, or a small dewar flask containing liquid nitrogen to cool the detector. A pulse height analyzer (PHA) generates a spectrum of data for each sample consisting of the number of fluorescent x-rays detected as a function of their energy level. The PHA can also store spectrum data for a number of samples in the field. A processing unit can be attached to the pulse height analyzer to upload and analyze the stored spectrum data for each sample. The processing unit provides a graphic display of the spectrum data for each sample, and provides qualitative and/or quantitative analysis of the elemental composition of the sample by comparing the peaks in the sample spectrum against known x-ray energies for various chemical elements. An optional filtration enclosure can be used to filter particles from a sample suspension, either in the form of a natural suspension or a chemically created precipitate. The sensor unit is then temporarily attached to the filtration unit to analyze the particles collected by the filter medium.

Thornton, Michael G.↗
NASA NTRS2009

Weekly Cycle of Lightning: Evidence of Storm Invigoration by Pollution

We have examined summertime 1998 2009 U.S. lightning data from the National Lightning Detection Network (NLDN) to look for weekly cycles in lightning activity. As was found by Bell et al. (2008) for rain over the southeast U.S., there is a significant weekly cycle in afternoon lightning activity that peaks in the middle of the week there. The weekly cycle appears to be reduced over population centers. Lightning activity peaks on weekends over waters near the SE U.S. The statistical significance of weekly cycles over the western half of the country is generally small. We found no evidence of a weekly cycle of synoptic-scale forcing that might explain these patterns. The lightning behavior is entirely consistent with the explanation suggested by Bell et al. (2008) for the cycles in rainfall and other atmospheric data from the SE U.S., that aerosols can cause storms to intensify in humid, convectively unstable environments.

Bell, Thomas L.↗
NASA NTRS2012

Analyzers Measure Greenhouse Gases, Airborne Pollutants

In complete darkness, a NASA observatory waits. When an eruption of boiling water billows from a nearby crack in the ground, the observatory s sensors seek particles in the fluid, measure shifts in carbon isotopes, and analyze samples for biological signatures. NASA has landed the observatory in this remote location, far removed from air and sunlight, to find life unlike any that scientists have ever seen. It might sound like a scene from a distant planet, but this NASA mission is actually exploring an ocean floor right here on Earth. NASA established a formal exobiology program in 1960, which expanded into the present-day Astrobiology Program. The program, which celebrated its 50th anniversary in 2010, not only explores the possibility of life elsewhere in the universe, but also examines how life begins and evolves, and what the future may hold for life on Earth and other planets. Answers to these questions may be found not only by launching rockets skyward, but by sending probes in the opposite direction. Research here on Earth can revise prevailing concepts of life and biochemistry and point to the possibilities for life on other planets, as was demonstrated in December 2010, when NASA researchers discovered microbes in Mono Lake in California that subsist and reproduce using arsenic, a toxic chemical. The Mono Lake discovery may be the first of many that could reveal possible models for extraterrestrial life. One primary area of interest for NASA astrobiologists lies with the hydrothermal vents on the ocean floor. These vents expel jets of water heated and enriched with chemicals from off-gassing magma below the Earth s crust. Also potentially within the vents: microbes that, like the Mono Lake microorganisms, defy the common characteristics of life on Earth. Basically all organisms on our planet generate energy through the Krebs Cycle, explains Mike Flynn, research scientist at NASA s Ames Research Center. This metabolic process breaks down sugars for energy to fuel cellular functions. "We think this chemical process did not exist when life first formed on Earth," he says, "because it is based on oxygen being available, and there was little oxygen available on the early Earth." It is possible that there are anaerobic regions beneath the sea floor in which life forms like those early non-Krebs Cycle microbes may yet exist. To detect and potentially collect samples of life emerging from hydrothermal vents, Flynn and his colleagues created Medusa, a multi-sensor instrument designed for long-term observation of diked vents on the ocean floor. When the vents erupt, Medusa assesses indicators of life within the expelled water. If the results are positive, the observatory collects samples and detaches from the ocean floor, making the long journey to the surface for retrieval by scientists. One of the indicators Medusa measures is the ratio of carbon isotopes in the water, namely carbon-12 and carbon-13. Living organisms preferentially take up carbon-12, Flynn says, so examining the ratio of these isotopes can help to determine the source of carbon in an environment as either biological or non-biological. "On Mars, there is evidence of localized methane in the atmosphere, and that methane could come from biological sources or from geochemical ones," Flynn says. "Determining the background planetary carbon isotope ratios and then evaluating the specific carbon ratios in this methane would help to determine how it was formed." A long-duration observatory similar to Medusa could one day provide essential evidence for or against the presence of life on the Red Planet or beneath the ice-crusted oceans of Europa.

Source record↗
NASA NTRS2012

Using Satellite Remote Sensing and Modelling for Insights into N02 Air Pollution and NO2 Emissions

Nitrogen oxides (NO(x)) are key actors in air quality and climate change. Satellite remote sensing of tropospheric NO2 has developed rapidly with enhanced spatial and temporal resolution since initial observations in 1995. We have developed an improved algorithm and retrieved tropospheric NO2 columns from Ozone Monitoring Instrument. Column observations of tropospheric NO2 from the nadir-viewing satellite sensors contain large contributions from the boundary layer due to strong enhancement of NO2 in the boundary layer. We infer ground-level NO2 concentrations from the OMI satellite instrument which demonstrate significant agreement with in-situ surface measurements. We examine how NO2 columns measured by satellite, ground-level NO2 derived from satellite, and NO(x) emissions obtained from bottom-up inventories relate to world's urban population. We perform inverse modeling analysis of NO2 measurements from OMI to estimate "top-down" surface NO(x) emissions, which are used to evaluate and improve "bottom-up" emission inventories. We use NO2 column observations from OMI and the relationship between NO2 columns and NO(x) emissions from a GEOS-Chem model simulation to estimate the annual change in bottom-up NO(x) emissions. The emission updates offer an improved estimate of NO(x) that are critical to our understanding of air quality, acid deposition, and climate change.

Lamsal, L. N.↗
NASA NTRS2011

Influence of Convection and Aerosol Pollution on Ice Cloud Particle Effective Radius

Satellite observations show that ice cloud effective radius (r(sub e)) increases with ice water content (IWC) but decreases with aerosol optical thickness (AOT). Using least-squares fitting to the observed data, we obtain an analytical formula to describe the variations of r(sub e) with IWC and AOT for several regions with distinct characteristics of r(sub e) -IWC-AOT relationships. As IWC directly relates to convective strength and AOT represents aerosol loading, our empirical formula provides a means to quantify the relative roles of dynamics and aerosols in controlling r(sub e) in different geographical regions, and to establish a framework for parameterization of aerosol effects on r(sub e) in climate models.

Jiang, J. H.↗
NASA NTRS2013

Chemical Pollution from Combustion of Modern Spacecraft Materials

Fire is one of the most critical contingencies in spacecraft and any closed environment including submarines. Currently, NASA uses particle based technology to detect fires and hand-held combustion product monitors to track the clean-up and restoration of habitable cabin environment after the fire is extinguished. In the future, chemical detection could augment particle detection to eliminate frequent nuisance false alarms triggered by dust. In the interest of understanding combustion from both particulate and chemical generation, NASA Centers have been collaborating on combustion studies at White Sands Test Facility using modern spacecraft materials as fuels, and both old and new technology to measure the chemical and particulate products of combustion. The tests attempted to study smoldering pyrolysis at relatively low temperatures without ignition to flaming conditions. This paper will summarize the results of two 1-week long tests undertaken in 2012, focusing on the chemical products of combustion. The results confirm the key chemical products are carbon monoxide (CO), hydrogen cyanide (HCN), hydrogen fluoride (HF) and hydrogen chloride (HCl), whose concentrations depend on the particular material and test conditions. For example, modern aerospace wire insulation produces significant concentration of HF, which persists in the test chamber longer than anticipated. These compounds are the analytical targets identified for the development of new tunable diode laser based hand-held monitors, to replace the aging electrochemical sensor based devices currently in use on the International Space Station.

Mudgett, Paul D.↗
NASA NTRS2013

Source Attributions of Pollution to the Western Arctic During the NASA ARCTAS Field Campaign

We use the NASA GEOS-5 transport model with tagged tracers to investigate the contributions of different regional sources of CO and black carbon (BC) to their concentrations in the Western Arctic (i.e., 50-90 deg N and 190- 320 deg E) in spring and summer 2008. The model is evaluated by comparing the results with airborne measurements of CO and BC from the NASA Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS) field campaigns to demonstrate the strengths and limitations of our simulations. We also examine the reliability of tagged CO tracers in characterizing air mass origins using the measured fossil fuel tracer of dichloromethane and the biomass burning tracer of acetonitrile. Our tagged CO simulations suggest that most of the enhanced CO concentrations (above background level from CH4 production) observed during April originate from Asian anthropogenic emissions. Boreal biomass burning emissions and Asian anthropogenic emissions are of similar importance in July domain wise, although the biomass burning CO fraction is much larger in the area of the ARCTAS field experiments. The fraction of CO from Asian anthropogenic emissions is larger in spring than in summer. European sources make up no more than 10% of CO levels in the campaign domain during either period. Comparisons of CO concentrations along the flight tracks with regional averages from GEOS-5 show that the alongtrack measurements are representative of the concentrations within the large domain of the Western Arctic in April but not in July.

Black Carbon↗
NASA NTRS2014

Geostationary Coastal and Air Pollution Events (GeoCAPE) Filter Radiometer (FR)

The GeoCAPE Filter Radiometer (FR) Study is a different instrument type than all of the previous IDL GeoCape studies. The customer primary goals are to keep mass, volume and cost to a minimum while meeting the science objectives and maximizing flight opportunities by fitting on the largest number of GEO accommodations possible. Minimize total mission costs by riding on a commercial GEO satellite. For this instrument type, the coverage rate, km 2 min, was significantly increased while reducing the nadir ground sample size to 250m. This was accomplished by analyzing a large 2d area for each integration period. The field of view will be imaged on a 4k x 4k detector array of 15 micrometer pixels. Each ground pixel is spread over 2 x 2 detector pixels so the instantaneous field of view (IFOV) is 2048 X 2048 ground pixels. The baseline is, for each field of view 50 sequential snapshot images are taken, each with a different filter, before indexing the scan mirror to the next IFOV. A delta would be to add additional filters.

Geo Cape↗
NASA NTRS2014

Air Pollution Over the Ganges Basin and Northwest Bay of Bengal in the Early Postmonsoon Season Based on NASA MERRAero Data

The MERRA Aerosol Reanalysis (MERRAero) has been recently developed at NASA's Global Modeling Assimilation Office. This reanalysis is based on a version of the Goddard Earth Observing System-5 (GEOS-5) model radiatively coupled with Goddard Chemistry, Aerosol, Radiation, and Transport aerosols, and it includes assimilation of bias-corrected aerosol optical thickness (AOT) from the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor on both Terra and Aqua satellites. In October over the period 2002-2009, MERRAero showed that AOT was lower over the east of the Ganges basin than over the northwest of the Ganges basin: this was despite the fact that the east of the Ganges basin should have produced higher anthropogenic aerosol emissions because of higher population density, increased industrial output, and transportation. This is evidence that higher aerosol emissions do not always correspond to higher AOT over the areas where the effects of meteorological factors on AOT dominate those of aerosol emissions. MODIS AOT assimilation was essential for correcting modeled AOT mainly over the northwest of the Ganges basin, where AOT increments were maximal. Over the east of the Ganges basin and northwest Bay of Bengal (BoB), AOT increments were low and MODIS AOT assimilation did not contribute significantly to modeled AOT. Our analysis showed that increasing AOT trends over northwest BoB (exceeding those over the east of the Ganges basin) were reproduced by GEOS-5, not because of MODIS AOT assimilation butmainly because of the model capability of reproducing meteorological factors contributing to AOT trends. Moreover, vertically integrated aerosol mass flux was sensitive to wind convergence causing aerosol accumulation over northwest BoB.

AOT↗