Earth Sciences
Atmospheric Science
Atmospheric science at JPL is conducted by a diverse set of researchers who track ozone recovery, quantify tropospheric pollutants such as aerosols, ozone, and carbon
monoxide, and develop state-of-the-art atmospheric models. All of these efforts complement each other as instrument, lab study, and modeling teams collaborate to improve their measurements and understandings of current atmospheric conditions.
The study of Earth's environment and its preservation and improvement are at the heart of spaceborne experiments. Flight experiment scientists are:
- Studying hurricanes and other aspects of weather from orbiting spacecraft in order to better understand these phenomena
- Measuring cloud properties and aerosol particles in the atmosphere and mapping vegetated and icy areas
- Observing stratospheric ozone to characterize depletion and the resulting ozone hole
- Mapping the global distribution of water vapor, the most abundant of the greenhouse gases, in order to understand its effect on climate change
- Mapping tropospheric ozone distribution to study global air quality
- Measuring fundamental spectroscopic and kinetic parameters that are critical to the interpretation of the remotely sensed data
Remote Sensing Observations
JPL is responsible for the integrity and analysis of the data that returns to earth from various instrument on NASA’s A-Train constellation of earth observing spacecrafts. Many of these spacecrafts have on-board instruments that, using various techniques, remotely observe the earth’s atmosphere.
Tropospheric Emission Spectrometry
Work performed in this area is centered on the data returned from the Tropospheric Emission Spectrometer (TES) experiment on the EOS-Aura satellite. TES is an infrared Fourier Transform Spectrometer designed to make global measurements of tropospheric ozone and its chemical precursors.
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Ozone and Carbon Monoxide measurements from the TES instrument
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Microwave Atmospheric Science
Microwave instruments are used to obtain information about the chemistry, hydrology, and dynamics of Earth's atmosphere. Its overall goal is to produce information that is needed for understanding and protecting the health of our atmosphere - using the unique capabilities and infrastructure provided by JPL and NASA. Research in this area is 'anchored' on the Microwave Limb Sounder (MLS) experiments, which were initiated at JPL in the early 1970s - starting with aircraft, progressing through balloon and then satellite instruments.
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EOS MLS measurements of ozone loss during the 2004-05 Arctic winter
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The first MLS satellite experiment was on the Upper Atmosphere Research Satellite (UARS), launched in 1991 to assess the chlorine threat to stratospheric ozone. The second, EOS MLS, is on the EOS Aura satellite, launched July 15 2004, with an expected operational lifetime of at least five years. The overall objectives of EOS MLS are to:
- Track recovery of ozone layer chemistry
- Provide information on how atmospheric composition affects climate
- Provide information on pollution in the upper troposphere
The EOS MLS measures many more chemical species than were possible with the first MLS, due to infusion of new submillimeter technology developed at JPL.
Aerosol and Cloud Science
The MISR instrument on board the Terra spacecraft collects multi-angle as well as multi-spectral data never before obtained by satellite instruments. The additional information contained in these data make it possible to set limits on particle size and composition, as well as aerosol amount, measured over ocean. The data is also be used to derive aerosol properties in the atmosphere over heterogeneous land and dense dark vegetation. Researchers use different methods to derive aerosol properties over different types of surface.
MISR also significantly adds to current understanding of clouds and solar radiation in several ways, but its most important contributions will be to provide more accurate estimates of cloud albedo. MISR's nine cameras span much of the range of angles over which cloud reflectivity varies. The albedo retrieved by MISR are expected to be ten times more accurate than those obtained from similar measurements with only a single camera looking straight down.
In Situ Atmospheric Measurements
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JPL makes many in situ measurements of the atmosphere and is able to routinely support field campaigns. Many scientists conducting studies with in situ instruments are active in validation and other campaigns that take place several times a year. Balloons are able to lift their payloads about 99.7% of the earth’s atmosphere so that they can more accurately measure vertical profiles of atmospheric gases.
Mark IV Interferometer
A Mark IV interferometer team uses a mid-infrared Fourier transform interferometer to measure the atmosphere using the Sun as a source. The Mark IV interferometer can be deployed in a stratospheric balloon gondola, on aircraft, or on the ground.
Balloon OH (BOH) measurements
This instrument mounted on a balloon uses a heterodyne radiometer to detect thermal emission from the OH radical in the Earth's stratosphere. BOH is deployed in a stratospheric balloon gondola and is used to validate OH measurements made by the Microwave Limb Sounder (MLS) instrument on the Aura satellite.
Submillimeter Limb Sounder (SLS) instrument
SLS uses a cryogenic heterodyne radiometer to detect thermal emission from multiple molecules near 640 GHz in the Earth's stratosphere. SLS is deployed in a stratospheric balloon gondola or on aircraft.
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Figure above shows profiles of normalized Potential Vorticity (sPV) for the dates and locations of various MkIV balloon flights
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LIDAR Measurements
LIDAR is used by groups at JPL to measure tropospheric and stratospheric temperature, ozone and water. Instrumentation is housed at Table Mountain and in Hawaii.
The LIDAR group has expertise in remote sensing instrumentation, and retrievals as well as atmospheric science. There are close ties with the MLS project, the TES project, the OCO project, and the Network for Detection of Stratospheric Change.
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The 5-year ozone climatology shows a very well pronounced annual cycle around 15 km characterized by a maximum in late winter/spring, and a minimum in late summer/fall. (Figure on the left is TMO, right is TMF.)
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Laboratory Studies and Modeling
Laboratory Studies
This activity involves the use of state-of-the-art experimental techniques to measure kinetic, photochemical and spectroscopic parameters related to elementary atmospheric processes. Rate coefficients, cross sections and quantum yields are measured using methods such as laser photolysis, discharge-flow and steady-state photolysis combined with high-sensitivity detection methods such as molecular beam mass spectrometry, long-path UV-visible-NIR absorption, diode laser wavelength modulation spectroscopy and laser-induced fluorescence.
Particular importance is placed on processes that play important roles in polar ozone depletion, long-term trends in stratospheric ozone at mid-latitudes, the oxidizing potential of the troposphere, and the formation of oxidants in urban and regional environments.
Quantitative spectroscopy is another key focus of the laboratory studies program. JPL’s Molecular Spectroscopy Team takes measurements of molecules from the microwave through the ultraviolet spectral regions to measure spectroscopic parameters of atmospheric molecules with extremely high precision and accuracy. These parameters are required for the measurement of atmospheric composition and structure by NASA remote sensing instruments for studies in Earth and planetary sciences, astrobiology and astrophysics.
Modeling
In this area, computer models of atmospheric processes are developed and used to interpret data from field measurements, as prognostic tools to understand long-term changes in climate and composition, and to diagnose elementary processes in atmospheric transport and chemistry.
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For tropospheric studies, the group uses a three-dimensional chemical transport model that incorporates winds derived from a weather model. In combination with detailed emission inventories of trace gases, this model has been used to study long-range pollution transport, the effects of biomass burning on global air quality, and the relationships between large-scale weather features and patterns in trace-gas composition. Another important objective is to compare global measurements of trace gases from space with model calculations. This GEOS-Chem model conducts validation activities with many of JPL’s science teams.
The group also has a strong emphasis on stratospheric modeling. This work focuses on the comparison of aircraft, satellite, balloon and ground-based measurements with model predictions to test the fundamental chemical processes that constrain the budgets of ozone and trace gases in the important lower stratosphere and upper troposphere regions.
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GEOS-Chem modeled CO2 during April 2003 at 300 hPa
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Contacts
Annmarie Eldering - Management Contact
E-Mail: Annmarie.Eldering@jpl.nasa.gov
Phone: 818.354.4941
Dong Wu - Aerosols and Clouds
E-Mail: Dong.L.Wu@jpl.nasa.gov
Phone: 818.393.1954
Michelle Santee - Microwave Atmospheric Science
E-Mail: Michelle.Santee@jpl.nasa.gov
Phone: 818.354.9424
Geoffrey Toon - Atmospheric Observations
E-Mail: Geoffrey.Toon@jpl.nasa.gov
Phone: 818.354.8259
Stanley Sander - Lab Studies and Modeling
E-Mail: Stanley.P.Sander@jpl.nasa.gov
Phone: 818.354.2625
John Worden - Tropospheric Emission Spectroscopy
E-Mail: John.R.Worden@jpl.nasa.gov
Phone: 818.393.7122
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