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NASA NTRSDate not supplied

1235 Preparing for TEMPO: A Review of Planned Metadata, Data Structure, and Distribution by NASA’s Atmospheric Science Data Center

The Atmospheric Science Data Center (ASDC) is in the Science Directorate located at the NASA Langley Research Center (LaRC), in Hampton, Virginia. The ASDC is one of NASA’s Distributed Active Archive Centers (DAAC) and supports over 60 projects and provides access to more than 1,000 archived collections. These datasets were created from satellite measurements, field experiments, and modeled data products. ASDC projects focus on the following Earth science disciplines: Radiation Budget, Clouds, Aerosols, and Tropospheric Composition. The ASDC is the official Distributed Active Archive Center (DAAC) of record for the upcoming Tropospheric Emissions: Monitoring of Pollution (TEMPO) instrument.. The instrument will share a ride on a commercial satellite as a hosted payload and will be launched to an orbit about 22,000 miles above Earth's equator. The investigation will, for the first time, use a space-based instrument to make accurate observations of tropospheric pollution concentrations of ozone, nitrogen dioxide, formaldehyde, and aerosols with high resolution and frequency over the U.S, Canada, and Mexico.

Ashlee Autore↗

NASA NTRSDate not supplied

1235 Preparing for TEMPO: A Review of Planned Metadata, Data Structure, and Distribution by NASA’s Atmospheric Science Data Center

Ashlee Autore↗

NASA NTRSDate not supplied

Near Real Time Air Quality Forecasts Using the NASA GEOS Model

This presentation provides an overview of NASA's Global Modeling and Assimilation Office (GMAO) high-resolution global forecast and reanalysis products for weather, aerosols, and air quality. The NASA Global Earth Observing System (GEOS) model radiatively coupled to GOCART aerosol module assimilates 2-dimensional column-integrated aerosol optical depth (AOD) at one wavelength (550 nm) in order to constrain the model's background AOD in order to have the best historical estimate and forecasts of AOD and particulate matter. Furthermore, the GEOS model has been expanded to provide global near-real-time 5-day forecasts of atmospheric composition at unprecedented horizontal resolution of 0.25 degrees (~25 km). This composition forecast system (GEOS-CF) combines the operational GEOS weather forecasting model with the state-of-the-science GEOS-Chem chemistry module (version 12) to provide detailed analysis of a wide range of air pollutants such as ozone, carbon monoxide, nitrogen oxides, and fine particulate matter (PM2.5).

K Emma Knowland↗

NASA NTRSDate not supplied

Near Real Time Air Quality Forecasts Using the NASA GEOS Model

K Emma Knowland↗

NASA NTRSDate not supplied

Enabling Analysis of Air Quality Data From Tropospheric Emissions: Monitoring of POllution (Tempo) Via Cloud-Based Tools

Launched in April 2023, the Tropospheric Emissions: Monitoring of POllution (TEMPO) instrument provides high-resolution measurements of key atmospheric pollutants, such as ozone, nitrogen dioxide, and formaldehyde. Maximizing the use and utility of this new source of air quality information requires streamlining data access for a wide variety of research, public health, and other interested users. These varied applications often require the data to be structured in different ways, e.g., specific formats, array shapes, or file sizes. To enable access to TEMPO data in different forms, the NASA Atmospheric Science Data Center (ASDC), as part of the NASA Earth Science Data and Information System (ESDIS), provides a variety of cloud-based data transformation and GIS visualization tools. This presentation demonstrates methods of accessing and working with TEMPO data through these services, while highlighting aspects of the software and algorithmic workflows that perform the necessary data transformations. Examples include data subsetting, concatenation, and visualizations accessible via Jupyter notebooks and GIS software.

Daniel Kaufman↗

NASA NTRS2010

Increasing Springtime Ozone Mixing Ratios in the Free Troposphere Over Western North America

In the lowermost layer of the atmosphere - the troposphere - ozone is an important source of the hydroxyl radical, an oxidant that breaks down most pollutants and some greenhouse gases. High concentrations of tropospheric ozone are toxic, however, and have a detrimental effect on human health and ecosystem productivity1. Moreover, tropospheric ozone itself acts as an effective greenhouse gas. Much of the present tropospheric ozone burden is a consequence of anthropogenic emissions of ozone precursors resulting in widespread increases in ozone concentrations since the late 1800s. At present, east Asia has the fastest-growing ozone precursor emissions. Much of the springtime east Asian pollution is exported eastwards towards western North America. Despite evidence that the exported Asian pollution produces ozone, no previous study has found a significant increase in free tropospheric ozone concentrations above the western USA since measurements began in the late 1970s. Here we compile springtime ozone measurements from many different platforms across western North America. We show a strong increase in springtime ozone mixing ratios during 1995-2008 and we have some additional evidence that a similar rate of increase in ozone mixing ratio has occurred since 1984. We find that the rate of increase in ozone mixing ratio is greatest when measurements are more heavily influenced by direct transport from Asia. Our result agrees with previous modelling studies, which indicate that global ozone concentrations should be increasing during the early part of the twenty-first century as a result of increasing precursor emissions, especially at northern mid-latitudes, with western North America being particularly sensitive to rising Asian emissions. We suggest that the observed increase in springtime background ozone mixing ratio may hinder the USA s compliance with its ozone air quality standard.

Cooper, O. R.↗

NASA NTRS1995

Environmentally regulated aerospace coatings

Aerospace coatings represent a complex technology which must meet stringent performance requirements in the protection of aerospace vehicles. Topcoats and primers are used, primarily, to protect the structural elements of the air vehicle from exposure to and subsequent degradation by environmental elements. There are also many coatings which perform special functions, i.e., chafing resistance, rain erosion resistance, radiation and electric effects, fuel tank coatings, maskants, wire and fastener coatings. The scheduled promulgation of federal environmental regulations for aerospace manufacture and rework materials and processes will regulate the emissions of photochemically reactive precursors to smog and air toxics. Aerospace organizations will be required to identify, qualify and implement less polluting materials. The elimination of ozone depleting chemicals (ODC's) and implementation of pollution prevention requirements are added constraints which must be addressed concurrently. The broad categories of operations affected are the manufacture, operation, maintenance, and repair of military, commercial, general aviation, and space vehicles. The federal aerospace regulations were developed around the precept that technology had to be available to support the reduction of organic and air toxic emissions, i.e., the regulations cannot be technology forcing. In many cases, the regulations which are currently in effect in the South Coast Air Quality Management District (SCAQMD), located in Southern California, were used as the baseline for the federal regulations. This paper addresses strategies used by Southern California aerospace organizations to cope with these regulatory impacts on aerospace productions programs. All of these regulatory changes are scheduled for implementation in 1993 and 1994, with varying compliance dates established.

Morris, Virginia L.↗

NASA NTRS2000

Introduction to the SONEX (Subsonic Assessment Ozone and Nitrogen Oxides Experiment) and POLINAT-2 (Pollution from Aircraft Emissions in the North Atlantic Flight Corridor) Special Issue

Emissions of atmospheric species from the engines of subsonic aircraft at cruise altitude (roughly, above seven kilometers) are of concern to scientists, the aviation industry and policymakers for two reasons. First, water vapor, soot and sulfur oxides, and related heterogeneous processes, may modify clouds and aerosols enough to perturb radiative forcing in the UT/LS (upper troposphere/lower stratosphere). A discussion of these phenomena appears in Chapter 3 of the IPCC Aviation Assessment (1999). An airborne campaign conducted to evaluate aviation effects on contrail, cirrus and cloud formation, is described in Geophysical Research Letters. The second concern arises from subsonic aircraft emissions of nitrogen oxides (NO + NO2 = NO(sub x)), CO, and hydrocarbons. These species may add to the background mixture of photochemically reactive species that form ozone. In the UT/LS, ozone is a highly effective greenhouse gas. The impacts of subsonic aircraft emissions on tropospheric NO(sub x) and ozone budgets have been studied with models that focus on UT chemistry [e.g. see discussions of individual models in Brasseur et al., 1998; Friedl et al., 1997; IPCC, 1999]. Depending on the model used, projected increases in the global subsonic aircraft fleet from 1992 to 2015 will lead to a 50-100 pptv increase in UT/LS NO. at 12 km (compared to 50-150 pptv background) in northern hemisphere midlatitudes. The corresponding 12-km ozone increase is 7-11 ppbv, or 5-10% (Chapter 4 in IPCC, 1999). Two major sources of uncertainties in model estimates of aviation effects are: (1) the often limited degree to which global models - the scale required to evaluate aircraft emissions - realistically simulate atmospheric transport and other physical processes; (2) limited UT/LS observations of trace gases with which to evaluate model performance. In response to the latter deficiency, a number of airborne campaigns aimed at elucidating the effect of aircraft on atmospheric nitrogen oxides and ozone were performed between 1990 and 1996 (see descriptions in Friedl et al., 1997; Brasseur et al., 1998).

Thompson, Anne M.↗

NASA NTRS2004

The EOS-Aura Mission

The EOS-Aura atmospheric chemistry mission is scheduled for launch in June 2004. Aura is the third of the large EOS observatories. The spacecraft carries an international instrument payload that has a planned six year lifetime. The Aura mission will collect data to help answer stratospheric and tropospheric atmospheric chemistry questions. The mission has the following four major objectives: 1) Track the ozone layer to determine if it is recovering as predicted. The four Aura instruments, HIRDLS, OMI, MLS, and TES will measure ozone, key source, radical, reservoir, tracer gases, and aerosols. Aura's unique design allows for major ozone controlling gases to be measured within the same air mass within a few minutes. The OMI instrument will continue the trends fiom NASA's TOMS series. 2) Track tropospheric pollutant sources and measure tropospheric ozone precursors. Major pollution sources include urban, industrial and biomass burning regions. Tropospheric trace gases will be measured, using TES and OMI, at an average spatial resolution of about approximately 15 km with near global coverage. 3) Measure key upper tropospheric atmospheric constituents that influence climate. The Aura instruments will monitor O3, H2O, CO, cirrus ice, and aerosols. EOS-Aura will fly in a sun-synchronous polar orbit about 15 minutes behind Aqua and make near coincident and synergistic measurements with the EOS- Aqua, Cloudsat, OCO, PARASOL and Calipso missions. Aura launched July 15,2004.

Schoeberl, Mark R.↗

NASA NTRS2005

The EOS-Aura Mission

The EOS-Aura atmospheric chemistry mission is scheduled for launch in June 2004. Aura is the third of the large EOS observatories. The spacecraft carries an international instrument payload that has a planned six year lifetime. The Aura mission will collect data to help answer stratospheric and tropospheric atmospheric chemistry questions. The mission has the following four major objectives: 1) Track the ozone layer to determine if it is recovering as predicted. The four Aura instruments, HIRDLS, OMI, MLS, and TES will measure ozone, key source, radical, reservoir, tracer gases, and aerosols. Aura's unique design allows for major ozone controlling gases to be measured within the same air mass within a few minutes. The OMI instrument will continue the trends from NASA's TOMS series. 2) Track tropospheric pollutant sources and measure tropospheric ozone precursors. Major pollution sources include urban, industrial and biomass burning regions. Tropospheric trace gases will be measured, using TES and OMI, at an average spatial resolution of about approx. 15 km with near global coverage. 3) Measure key upper tropospheric atmospheric constituents that influence climate. The Aura instruments will monitor O3, H2O, CO, cirrus ice, and aerosols. EOS-Aura will fly in a sun-synchronous polar orbit about 15 minutes behind Aqua and make near coincident and synergistic measurements with the EOS-Aqua, Cloudsat, OCO, PARASOL and Calipso missions. Aura launched July 15,2004.

Schoeberl, Mark R.↗

NASA NTRS2019

Characterizing Spatio-Temporal Ozone Gradients Along Coastal Boundaries: Sondes and Mobile Measurements from OWLETS-2

One of the major difficulties for the modeling and satellite communities is the validation of O3 levels in sharp coastal transition regions within metropolitan areas. Land-water gradients of ozone as well as its precursors can be significant due to differences in emissions, land use, surface deposition, boundary layer height, and mesoscale wind patterns. The Ozone Water-Land Environmental Transition Study (OWLETS-2) was a follow-on field campaign spearheaded by NASA GSFC and LaRC's Tropospheric Ozone Lidar Network (TOLnet) conducted in the summer of 2018 within the Upper Chesapeake region to better characterize spatial and vertical distribution of various pollutants across the coastal boundary. Supporting this campaign, 40 ozonesondes were simultaneously launched directly in the marine environment on Hart Miller Island (HMI) and on two land sites: both the University of Maryland, Baltimore County (UMBC) and Howard University-Beltsville (HUBV). In addition, Personal Ozone Monitors (POMs) - small sensors - were deployed in a variety of environments - car, boat, and drone, to name a few - to quantify ozone across fine spatial and temporal thresholds. The purpose of these measurements is multifaceted: to provide both ozone pollution information to coastal metropolitan communities and validation to satellite, modeling, and forecasting communities, especially in current and future satellite endeavors such as TROPOMI and TEMPO.

coastal pollution↗

NASA NTRS1995

Explaining the Accumulation of Intercontinental Biomass Burning Pollution: High Versus Low Processes, Africa Versus South America, Cooking Versus Mixing

The intercontinental buildup of tropospheric ozone, carbon monoxide, and other pollutants over the South Atlantic has been attributed to biomass burning over distant continents. We address several of the large questions regarding the nature and budget of this buildup have remained: What is the role of turning In South America or various portions of Africa in this accumulation? What are the relative roles of shallow and deep convection for emplacing various compounds in the free troposphere? Can we understand the ozone budget? We report the first simulations of a three-dimensional pollutant transport model, (GRACES) transport which is driven by fully reconstructed meteorology for the TRACE-A/SAFARI period of 1992. Greater detail is provided by a two-dimensional, detailed-chemistry model of more restricted regions of Africa. We find a predominant role for African emissions affecting the Atlantic during this period. Boundary-layer venting via PBL convection tends to build the observed carbon monoxide column over the ocean, while deep cumulonimbus processes tend to explain rather more of the ozone column.

Chatfield, Robert B.↗

NASA NTRS1994

An analysis of the impacts of global climate and emissions changes on regional tropospheric ozone

Many of the synergistic impacts resulting from future changes in emissions as well as changes in ambient temperature, moisture, and UV flux have not been quantified. A three-dimensional regional-scale photo-chemical model (STEM-2) is used in this study to evaluate these perturbations to trace gas cycles over the eastern half of the United States of America. The model was successfully used to simulate a regional-scale ozone episode (base case - June 1984) and four perturbations scenarios - viz., perturbed emissions, temperature, water vapor column, and incoming UV flux cases, and a future scenario (for the year 2034). The impact of these perturbation scenarios on the distribution of ozone and other major pollutants such as SO2 and sulfates were analyzed in detail. The spatial distribution and the concentration of ozone at the surface increased by about 5-15 percent for most cases except for the perturbed water vapor case. The regional scale surface ozone concentration distribution for the year 2034 (future scenario) showed an increase of non-attainment areas. The rural areas of Pennsylvania, West Virginia, and Georgia showed the largest change in the surface ozone field for the futuristic scenario when compared to the base case.

John, Kuruvilla↗

NASA NTRS2017

Lidar Observations Revealing Transport of O3 in the Presence of a Nocturnal Low-Level Jet: Regional Implications for "Next-Day" Pollution

Remotely sensed profiles of ozone (O3) and wind are presented continuously for the first time during anocturnal low-level jet (NLLJ) event occurring after a severe O3 episode in the Baltimore-Washington D.C.(BW) urban corridor throughout 11-12 June 2015. High-resolution O3 lidar observations indicate a well mixedand polluted daytime O3 reservoir, which decayed into a contaminated nocturnal residual layer(RL) with concentrations between 70 and 100 ppbv near 1 km above the surface. Observations indicatethe onset of the NLLJ was responsible for transporting polluted O3 away from the region, while simultaneouslyaffecting the height and location of the nocturnal residual layer. High-resolution modelinganalyses and next-day (12 June) lidar, surface, and balloon-borne observations indicate the trajectory ofthe NLLJ and polluted residual layer corresponds with ''next-day'' high O3 at sites throughout thesouthern New England region (New York, Connecticut, Massachusetts). The novel O3 lidar observationsare evidence of both nocturnal advection (via high NLLJ wind fields) and entrainment of the pollutedresidual layer in the presence of the ''next-day'' convectively growing boundary layer. In the greatercontext, the novel observational suite described in this work has shown that the chemical budget in areasdownwind of major urban centers can be altered significantly overnight during transport events such asthe NLLJ.

ozone↗

NASA NTRSDate not supplied

Global Burden of Tropospheric Ozone: Effects of Particulate Nitrate Photolysis and Assimilation of NO2 Measurements

Tropospheric ozone is a major pollutant, a greenhouse gas, and the primary source of the hydroxyl radical. It is largely produced in situ from the oxidation of CO and volatile organic compounds in the presence of nitrogen oxides (NOx=NO+NO2). Global atmospheric chemistry models generally underestimate NOx and CO concentrations in the northern hemisphere away from source regions, which would lead to an underestimate in the tropospheric ozone burden. Here we evaluate the tropospheric ozone simulation in the GEOS-Chem model (version 14) using observations from satellite, aircraft, and ozonesondes. We include GEOS-Chem simulations conducted in the standard offline mode, as well as in the online mode within the NASA GEOS earth system model which forms the basis for the GEOS Composition Forecasts (GEOS-CF). In both configurations, GEOS-Chem underestimates ozone concentrations in the northern midlatitude free troposphere in spring and summer. We find that we can improve the ozone simulation by including an additional NOx source over the oceans from particulate nitrate photolysis on sea salt aerosols at rates inferred from field studies over the Atlantic Ocean. We investigate whether further improvements in the ozone simulation can be achieved by assimilating satellite measurements of NO2 from the Ozone Monitoring Instrument (OMI) and CO from the Measurement of Pollution in the Troposphere (MOPITT) instruments.

tropospheric ozone↗

NASA NTRS1976

Effect of water vapor on the destruction of ozone in the stratosphere perturbed by ClX or NOx pollutants

Results are presented for a self-consistent one-dimensional coupled flow calculation for Ox, NOx, HOx, ClX, H2O, H2, CH4, H2O2, and N2O densities between 10 and 120 km. The results agree well with observations for the normal midlatitude atmosphere over this altitude range. ClX, NOx, and H2O are varied independently in the model considered. It is shown that the effect of depletion of ozone by ClX is to remove ozone preferentially above 30 km and to lower the altitude of maximum ozone density. This leads to enhanced solar heating of the lower stratosphere and tropopause and suggests the possibility of an increased flux of water into the stratosphere. Increasing water vapor in the stratosphere greatly enhances the rate of destruction of O3 by ClX and also causes an increase in the rate of destruction of O3 in the NOx-perturbed atmosphere.

Liu, S. C.↗

NASA NTRS2012

Tropospheric Ozone as a Short-lived Chemical Climate Forcer

Tropospheric ozone is the third most important greenhouse gas according to the most recent IPCC assessment. However, tropospheric ozone is highly variable in both space and time. Ozone that is located in the vicinity of the tropopause has the greatest effect on climate forcing. Nitrogen oxides (NOx) are the most important precursors for ozone In most of the troposphere. Therefore, pollution that is lofted upward in thunderstorm updrafts or NOx produced by lightning leads to efficient ozone production in the upper troposphere, where ozone is most important climatically. Global and regional model estimates of the impact of North American pollution and lightning on ozone radiative forcing will be presented. It will be shown that in the Northern Hemisphere summer, the lightning effect on ozone radiative forcing can dominate over that of pollution, and that the radiative forcing signal from North America extends well into Europe and North Africa. An algorithm for predicting lightning flash rates and estimating lightning NOx emissions is being incorporated into the NASA GEOS-5 Chemistry and Climate Model. Changes in flash rates and emissions over an ENSO cycle and in future climates will be assessed, along with the resulting changes in upper tropospheric ozone. Other research on the production of NOx per lightning flash and its distribution in the vertical based on cloud-resolving modeling and satellite observations will be presented. Distributions of NO2 and O3 over the Middle East from the OMI instrument on NASA's Aura satellite will also be shown.

Pickering, Kenneth E.↗

NASA NTRS1995

Linear operating region in the ozone dial photon counting system

Ozone is a relatively unstable molecule found in Earth's atmosphere. An ozone molecule is made up of three atoms of oxygen. Depending on where ozone resides, it can protect or harm life on Earth. High in the atmosphere, about 15 miles up, ozone acts as a shield to protect Earth's surface from the sun's harmful ultraviolet radiation. Without this shield, we would be more susceptible to skin cancer, cataracts, and impaired immune systems. Closer to Earth, in the air we breathe, ozone is a harmful pollutant that causes damage to lung tissue and plants. Since the early 1980's, airborne lidar systems have been used for making measurements of ozone. The differential absorption lidar (DIAL) technique is used in the remote measurement of O3. This system allows the O3 to be measured as function of the range in the atmosphere. Two frequency-doubled Nd:YAG lasers are used to pump tunable dye lasers. The lasers are operating at 289 nm for the DIAL on-line wavelength of O3, and the other one is operated at 300 nm for the off-line wavelength. The DIAL wavelengths are produced in sequential laser pulses with a time separation of 300 micro s. The backscattered laser energy is collected by telescopes and measured using photon counting systems. The photon counting system measures the light signal by making use of the photon nature of light. The output pulse from the Photo-Multiplier Tube (PE), caused by a photon striking the PMT photo-cathode, is amplified and passed to a pulse height discriminator. The peak value of the pulse is compared to a reference voltage (discrimination level). If the pulse amplitude exceeds the discrimination level, the discriminator generates a standard pulse which is counted by the digital counter. Non-linearity in the system is caused by the overlapping of pulses and the finite response time of the electronics. At low count rates one expects the system to register one event for each output pulse from the PMT corresponding to a photon incident upon the photocathode, however, at higher rates the limitations of the discrimination/counting system will cause the observed count rate to be non-linear with respect to the true count rate. Depending on the pulse height distribution and the discriminator level, the overlapping of pulses (pulse pile-up) can cause count loss or even an additional apparent count gain as the signal levels increase. Characterization of the system, including the pulse height distribution, the signal to noise ratio, and the effect of the discriminator threshold level, is critical in maximizing the linear operating region of the system, thus greatly increasing the useful dynamic range of the system.

Andrawis, Madeleine↗