K. Chance, X. Liu, C. Chan Miller, G. González Abad, G. Huang, C. Nowlan, A. Souri, R. Suleiman, K. Sun, H. Wang, L. Zhu, P. Zoogman, J. Al-Saadi, J. -C. Antuña-Marrero, J. Carr, R. Chatfield, M. Chin, R. Cohen, D. Edwards, J. Fishman, D. Flittner, J. Geddes, M. Grutter, J. Herman, D. Jacob, S. Janz, J. Joiner, J. Kim, N. Krotkov, B. Lefer, R. Martin, O. Mayol-Bracero, A. Naeger, M. Newchurch, G. Pfister, K. Pickering, R. Pierce, C. Rivera Cárdenas, A. Saiz-Lopez, W. Simpson, E. Spinei, R. J. Spurr, J. Szykman, O. Torres, J. Wang
The NASA/Smithsonian Tropospheric Emissions: Monitoring of Pollution (TEMPO; tempo.si.edu) satellite instrument will measure atmospheric pollution and much more over Greater North America at high temporal resolution (hourly or better in daylight, with selected observations at 10 minute or better sampling) and high spatial resolution (10 km2 at the center of the field of regard). It will measure ozone (O3) profiles (including boundary layer O3), and columns of nitrogen dioxide (NO2), nitrous acid (HNO2), sulfur dioxide (SO2), formaldehyde (H2CO), glyoxal (C2H2O2), water vapor (H2O), bromine oxide (BrO), iodine oxide (IO), chlorine dioxide (OClO), as well as clouds and aerosols, foliage properties, and ultraviolet B (UVB) radiation. The instrument has been delivered and is awaiting spacecraft integration and launch in 2022. This talk describes a selection of TEMPO applications based on the TEMPO Green Paper living document (http://tempo.si.edu/publications.html).
Applications to air quality and health will be summarized. Other applications presented include: biomass burning and O3 production; aerosol products including synergy with GOES infrared measurements; lightning NOx; soil NOx and fertilizer application; crop and forest damage from O3; chlorophyll and primary productivity; foliage studies; halogens in coastal and lake regions; ship tracks and drilling platform plumes; water vapor studies including atmospheric rivers, hurricanes, and corn sweat; volcanic emissions; air pollution and economic evolution; high-resolution pollution versus traffic patterns; tidal effects on estuarine circulation and outflow plumes; air quality response to power blackouts and other exceptional events.
Satellite observations of tropospheric carbon monoxide (CO) are employed in diverse applications including air quality studies, chemical weather forecasting and the characterization of CO emissions through inverse modeling. The TERRA / MOPITT ('Measurements of Pollution in the Troposphere') instrument incorporates a set of gas correlation radiometers to observe CO simultaneously in both a thermal-infrared (TIR) band near 4.7 µm and a near-infrared (NIR) band near 2.3 μm. This multispectral capability is unique to MOPITT. The MOPITT retrieval algorithm for vertical profiles of CO has been refined almost continuously since TERRA was launched at the end of 1999. Retrieval algorithm enhancements are the result of ongoing analyses of instrument performance, improved radiative transfer modeling, and systematic comparisons with correlative data, including in-situ profiles measured from aircraft and products from other satellite instruments. In the following, we describe the methods used to routinely evaluate MOPITT CO profiles. As the satellite instrument with the longest record for CO, methods for assessing the long-term stability are becoming increasingly important.
When the first observations of a tropospheric trace gas were obtained in the 1980s, carbon monoxide enhancements from
tropical biomass burning dominated the observed features. In 2005, an active remote-sensing system to provide detailed
information on the vertical distribution of aerosols and clouds was launched, and again, one of the most imposing
features observed was the presence of emissions from tropical biomass burning. This paper presents a brief overview of
space-borne observations of the distribution of trace gases and aerosols and how tropical biomass burning, primarily in
the Southern Hemisphere, has provided an initially surprising picture of the distribution of these species and how they
have evolved from prevailing transport patterns in that hemisphere. We also show how interpretation of these
observations has improved significantly as a result of the improved capability of trajectory modeling in recent years and
how information from this capability has provided additional insight into previous measurements form satellites.
The Atmospheric Infrared Sounder (AIRS) has been operating since Sept. 2002 and is being used operationally by several weather centers. Routine retrieval processing is done by NASA. Daytime AIRS measurements in the 4.3um region show large (upto 12 K) brightness temperature shifts compared to nighttime observations. The daytime shifts result from the preferential absorption of solar radiance in the upper atmosphere by CO2 and other molecules. This energy is transferred to many of the 4 um CO2 bands, driving them into a state of Non-Local Thermodynamic Equilibrium (NLTE). We present comparisons of observations against the results of a Fast Model we developed for the AIRS instrument, that includes this effect. This algorithm is fast enough to be used for retrievals, and will be especially useful for the 4.3um R branch head channels that are used for temperature sounding.
The data assimilation of 2000-2004 carbon monoxide (CO) retrievals by the MOPITT (Measurements Of Pollution In The Troposphere) instrument onboard the NASA Terra satellite provide an opportunity for the first time to study the transport and sources of pollution including their year-to-year variations. Based on the different representations of assimilated CO in the chemistry transport model (CTM) space and at the MOPITT retrieval grid this study advocates for direct mapping of CO-sensitive radiances or characterized CO retrievals by the chemical data assimilation schemes. The comprehensive CO forecast provides a great deal of information on the vertical scales that cannot be constrained by the measured radiances. It also provides comprehensive a priori specifications for the inverse problems especially for the vertical levels and geographical regions where the radiometer begins to misplace its high sensitivity to the CO loading. Evaluation of the multi-year MOPITT retrievals and assimilated CO against in situ CO statistics showed how the data assimilation helps to diminish a priori effects in the reprocessed CO retrievals. Data analysis of the multi-year data reveal substantial inter-annual variations of CO loading in the free troposphere and call for the unbiased tracer assimilation schemes in the CTM with optimized CO surface emissions.
Carbon monoxide (CO) is an important tropospheric trace species and can serve as a useful tracer of atmospheric transport. The Measurements of Pollution In The Troposphere (MOPITT) instrument uses the 4.7 μm CO band to measure the spatial and temporal variation of the CO profile and total column amount in the troposphere from space. Launched in 1999 on board the NASA Terra satellite, the MOPITT views the earth with a pixel size 22 km by 22 km and a cross-track swath that measures a near-global distribution of CO every 3 days. In the operational MOPITT CO retrieval algorithm (V3; Version 3), surface skin temperature (Ts) and emissivity (E) are retrieved simultaneously with the CO profile. The accuracy of E and Ts is crucial for obtaining the CO retrieval within the 10% accuracy from the MOPITT measurements. However, because both Ts and E are retrieved from the same piece of information from the MOPITT measurements, the accuracy of both valuables may be limited. Extra surface skin temperature information is needed to determine surface emissivity, and vice versa. In this study, we use MODIS Ts within the MOPITT FOVs, in conjunction with those MOPITT signals most sensitive to the background scene, to compute the surface emissivity through an iterative retrieval algorithm. A monthly 1degree grid averaged 4.7 μm surface emissivity map is generated. The evaluation of the accuracy of this monthly 1 degree grid averaged 4.7 μm surface emissivity map is presented and its impacts on the retrievals of tropospheric CO profiles from the MOPITT measurements are also discussed.
The Moderate-resolution Imaging Spectroradiometer (MODIS) provides aerosol optical depth (AOD) along with the fine mode fraction over ocean and darker land surfaces. Measurement Of Pollution In The Troposphere (MOPITT) onboard the Terra satellite provides quantitative information of carbon monoxide (CO). Measurements of CO whose principal sources arise from anthropogenic emissions such as biomass burning and forest fires, is very useful for tracing fire emissions in the atmosphere. In this study, intense fires in the southeast part of Russia in May, 2003 are studied with the satellite data from MODIS and MOPITT. The AOD distribution from the MODIS for May, 2003 show stretched regions of high AODs near the Korean Peninsula. The CO concentrations at 700 hPa from the MOPITT for May, 2003 also show enhanced values. Correlation between CO and AOD are investigated for the forest fire case. This multi-instrumental approach to monitor the aerosol in the atmosphere is expected to contribute to the classification of the aerosol characteristics in the atmosphere, carbonaceous aerosol in particular.
The Atmospheric Infrared Sounder (AIRS), launched in May 2002, is the first of a new generation of high-spectral resolution temperature and humidity sounders for numerical weather prediction and climate change studies. The accuracy of the AIRS radiances, and the validity of the clear sky AIRS Forward Model, have already been demonstrated. This paper presents global daytime measurements by the instrument, showing the effects of NLTE in the 4.3 μm CO2 band. Simulations using upper atmosphere NLTE temperatures are compared to actual AIRS measurements, for various solar angles.
The MOPITT (Measurements of Pollution in the Troposphere) Airborne Test Radiometer (MATR) uses gas filter correlation radiometry from high altitude aircraft to measure tropospheric carbon monoxide. This is in support of the ongoing validation campaign for the MOPITT instrument on board the Tera Satellite. This paper reports on a recent study of MATR CO retrievals using observations of thermal radiation during the autumn of 2001 in western United States. Retrievals of CO were performed and compared to in-situ sampling with less than 7% retrieval error relative to the in-situ total column amount. The effects that influence the retrieval such as the instrument sensitivity, the retrieval sensitivity, and bias between observations and the radiation model are discussed.
The Measurements of Pollution In The Troposphere (MOPITT) instrument is designed to measure the spatial and temporal variation of the carbon monoxide (CO) profile and total column amount in the troposphere from the space. MOPITT channels are sensitive to both thermal emission from the surface and target gas absorption and emission. Surface temperature and emissivity are retrieved simultaneously with the CO profile. To obtain the desired 10% precision for the retrieved CO from MOPITT measurements, it is important to understand MOPITT CO channel sensitivity to surface temperature and emissivity and the impacts of the effects of any errors in retrieved skin temperature and emissivity on retrieved CO for various underlying surfaces. To demonstrate the impacts of the surface temperature and emissivity on the retrieval of the tropospheric CO profile, simulation studies are performed. The collocated Moderate Resolution Imaging Spectroradiometer (MODIS) surface products are used to assess the accuracy of the retrieved MOPITT surface temperature and emissivity.
The measurements of Pollution in the Troposphere (MOPITT) instrument aboard the Earth Observing System (EOS) Terra spacecraft measures tropospheric CO and CH4 by use of a nadir-viewing geometry. MOPITT cloud algorithm detects and removes measurements contaminated by clouds before retrieving CO profiles and CO and CH4 total columns. The collocation between MOPITT and MODIS is also established and MODIS cloud mask will be used in the MOPITT cloud algorithm. The cloud detection results in the use of MOPITT data alone agree with MODIS cloud mask for more than 80% of the tested cases.
The Measurement Of Pollution In The Troposphere (MOPITT) instrument, which will be launched on the Terra spacecraft, is designed to measure the tropospheric CO and CH4 at a nadir-viewing geometry. The measurements are taken at 4.7 micrometer in the thermal region, and 2.3 and 2.2 micrometer in the solar region for CO mixing ratio retrieval, CO total column amount and CH4 column amount retrieval, respectively. To ensure the required measurement accuracy, it is critical to identify and remove any cloud contamination to the channel signals. In this study, we develop an algorithm to detect the cloudy pixels, to reconstruct clear column radiance for pixels with partial cloud covers, and to estimate equivalent cloud top positions under overcast conditions to enable CO profile retrievals above clouds. The MOPITT channel radiances, as well as the first guess calculations, are simulated using a fast forward model with input atmospheric profiles from ancillary data sets. The precision of the retrieved CO profiles and total column amounts in cloudy atmospheres is within the expected plus or minus 10% range. Validations of the cloud detecting thresholds with MODIS Airborne Simulator (MAS) data and MATR (MOPITT Airborne Test Radiometer) measurements are also carried out and will be presented separately.
This paper will serve as an overview of the challenges to the recovery of information on atmospheric CO and CH4 from the measurements made by the MOPITT instrument that has been described by Drummond et al. It will also provide a context and introduction to several of the following papers that go into greater detail on particular topics, and outline plans for the data processing. Here we briefly outline the principles of correlation radiometry as used by MOPITT, and introduce the principles behind the retrievals. After noting plans for data processing, we discuss our approach to data validation, and the ability to see global distributions of CO in the MOPITT data.
The MOPITT (Measurement of Pollution in the Troposphere) instrument, to be launched on the Earth Observing System Terra platform, employs gas-correlation spectroscopy to measure profiles of tropospheric carbon monoxide and the total column of methane. The modeling of the instrument, and the associated radiative transfer, comprise the forward model employed in the retrieval calculations. The MOPITT forward model has been implemented through a hierarchy of radiation codes whose salient features are reviewed here.
Laurence Rothman, Curtis Rinsland, Aaron Goldman, Steven Massie, David Edwards, Jean-Marie Flaud, Agnes Perrin, Claude Camy-Peyret, Victor Dana, Y.-Y. Mandin, John Schroeder, Robert Gamache, R. Wattson, Kouichi Yoshino, Kelly Chance, Kenneth Jucks, L. Brown, Vassilii Nemtchinov, Prasad Varanasi
Nineteen ninety-eight marks the 25th anniversary of the release of the first HITRAN database. HITRAN is recognized as the international standard of the fundamental spectroscopic parameters for diverse atmospheric and laboratory transmission and radiance calculations. There have been periodic editions of HITRAN over the past decades as the database has been expanded and improved with respect to the molecular species and spectral range covered, the number of parameters included, and the accuracy of this information. The 1996 edition not only includes the customary line-by-line transition parameters familiar to HITRAN users, but also cross-section data, aerosol indices of refraction, software to filter and manipulate the data, and documentation. This paper describes the data and features that have been added or replaced since the previous edition of HITRAN. We also cite instances of critical data that is forthcoming. A new release is planned for 1998.
KEYWORDS: Carbon monoxide, 3D modeling, In situ metrology, Radiometry, Solar radiation models, Algorithm development, Troposphere, Statistical modeling, Atmospheric modeling, Signal to noise ratio
We have developed a retrieval algorithm for deriving the tropospheric CO profile and column amount from the radiances measured by the Measurements of Pollution in the troposphere instrument. The main components of the algorithm are a fast radiative transfer model, based on the GENLN2 line-by-line model, and a maximum likelihood inversion method. The retrieval a priori information is derived from the results of several aircraft in situ measurements and a 3D chemical- transport model. This paper discusses the CO retrieval algorithm with an emphasis on the analysis and characterization of the algorithm. Forward model and retrieval sensitivities, along with the a priori information used in the retrieval are discussed in terms of their orthogonal components. Examples of ensemble retrieval experiments are also included.
The Measurements of Pollution in the Troposphere (MOPJTF) instrument is a
spaceborne gas correlation radiometer designed to measure CO and CH4 in the
troposphere. This instrument has been selected to be on board of the Earth Observing
System's first platform, EOS-AM, which is scheduled for launch in 1998. A maximum
likelihood retrieval algorithm has been selected for the MOPITT CO measurement in
clear sky conditions. Performance of the algorithm has been evaluated. This paper
describes the algorithm and presents the preliminary results of numerical retrieval
experiments.
In this paper we describe the scientific design work behind the selection of the IR spectral passbands for the 21 sounding channels of the high resolution dynamics limb sounder (HIRDLS) which is scheduled to fly aboard the Earth Observing System (EOS) chemistry platform at the beginning of the next century. At least one radiometer channel must be used for each gas that is being measured. Preferably the interfering contributions to the radiance by other gases in a channel should be small, but the principle requirements are that the desired emission be measured with high signal-to-noise ratio, and that there be separate channels for the measurement of interfering species. However, more than one channel is required to provide full altitude coverage of those target gases such as CO2, H2O, and O3, which have emission bands whose centers become optically thick in the middle atmosphere. Further channels, in which gaseous absorption is low, are required for the characterization of aerosol effects. We describe the HIRDLS channels selected for each gas, with emphasis on signal-to-noise considerations and altitude coverage, the elimination of contaminating signal between channels, and non-LTE processes for high altitude sounding and space view definition.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.