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SCIENCE DIRECTORATE
RESEARCH OPPORTUNITIES
Directorate Brief Description:
The Science Directorate
studies the Earth's atmosphere and how human activities influence it for a better understanding of
global change. The research focuses primarily on the Earth's radiation balance and climate,
atmospheric chemistry, and associated data management. They also support NASA's application programs
and educational outreach activities.
Branch Brief Description:
The Chemistry & Dynamics Branch
studies how air chemistry and dynamics influence the atmosphere. Research topics include, measurement
of the composition of the atmosphere, estimates of atmospheric pollution in the lower atmosphere, the
processes that affect the ozone layer, hurricane and weather forecasts, and atmospheric spectroscopy.
They also develop and use computer models that simulate atmospheric chemistry and transport processes.
Their expertise often supports the analysis of data from field experiments.
- Project Description:
Many observed changes in global atmospheric composition and associated chemistry can be linked to
anthropogenic activity. This opportunity solicits research to improve understanding of tropospheric
chemical cycles, both at a fundamental level and with respect to predicting future changes. High
priority is placed on understanding the transport and photochemical evolution of pollution as it moves
from local to regional scales and is ultimately incorporated into the global atmosphere. NASA
observations relevant to this pursuit include ground-based, airborne, and satellite observations. NASA
possesses an extensive database of in situ observations from both past and ongoing aircraft campaigns.
These campaigns have provided some of the most complete characterizations of tropospheric composition
ever obtained. Satellite observations from the Terra, Aqua, and Aura satellites include observations
of carbon monoxide, ozone, NO2, and other important tropospheric trace constituents. These satellite
measurements can provide long-term global coverage data. Modeling tools available to evaluate these
data sets include both simple box models as well as regional and global chemical models. Box models
are ideal for diagnosing basic chemical understanding through the prediction of observable quantities
(e.g., OH, HO2, CH2O, H2O2, HO2NO2, etc.). Box models are also useful for making observation-based
estimates of photochemical impacts such as ozone production rates, reactive nitrogen budgets, and
photochemical lifetimes both at a point as well as along a trajectory. These results are
complementary to regional and global models which address the combined effect of emissions, chemistry,
and transport processes on the spatial and temporal distributions of trace constituents, but are
limited in their ability to reproduce the true atmospheric state. We encourage investigations
incorporating both data analysis and modeling aimed at integrating in situ and satellite observations.
Such activities are critical to both validation of satellite observations as well as the
interpretation of satellite observations and their relevance to understanding tropospheric chemical
processes and future changes in atmospheric composition.
Desired Major(s): Tropospheric Chemical Studies
Key Words: Atmospheric chemistry; Atmospheric trace constituents;
Troposphere, Atmospheric modeling; Satellite measurements
Point of Contact Information: Gao Chen, Gao.Chen@nasa.gov, 757-864-2290
This project can be adapted for: (check all that are relevant)
[X] Post-Doc
[X] Faculty
[X] Graduate Students
[X] Undergraduate Students
[ ] High School Students
- Project Description:
Lidar techniques that have important applications to global investigations of atmospheric composition,
chemistry, and dynamics are being developed and applied from airborne and space-based platforms. The
differential absorption lidar (DIAL) technique has been used extensively in remote measurements of
ozone, water vapor, aerosol, and cloud distributions in regional and global atmospheric investigations
of important tropospheric and stratospheric processes. Airborne DIAL systems have been used for
several decades in national and international field experiments and as prototypes for future
space-based systems. The capabilities of the current DIAL systems can be expanded by the development
of novel DIAL techniques and systems for the measurement of other gases, such as carbon monoxide and
carbon dioxide, and in the development of advanced, compact lidar systems for high-altitude aircraft
and unattended aerial vehicles (UAVs). This will enable the investigation of atmospheric composition
and processes that are not amenable to study by current airborne DIAL systems. In addition, there are
many future applications of space-based DIAL systems to global atmospheric science investigations
associated with atmospheric composition, chemical weather, air quality, severe storms, radiation
budgets, and climate change, to name a few.
Major field experiments will be conducted with the current and newly developed airborne DIAL systems,
and the lidar data will be analyzed with respect to the atmospheric processes under investigation.
Comparisons of these lidar measurements will also be made to in situ balloon/aircraft measurements and
to remote ground-based and satellite measurements in important satellite validation experiments. The
future generation of space-based lidar systems for measurements of gases and aerosols will be
significantly influenced from the development of these advanced airborne lidar systems and in their
application to important atmospheric science investigations.
Desired Majors: Lidar Atmospheric Measurements of Gases and Aerosols
Key Words: Atmospheric Composition; Tropospheric Chemistry; Stratospheric Chemistry; Lidar; Active
Remote Sensing; Ozone; Water Vapor; Aerosols; Clouds
Point of Contact: Edward Browell, Edward.V.Browell@nasa.gov, 757-864-1273
This project can be adapted for:
[X] Post-Doc
[ ] Faculty
[ ] Graduate Students
[ ] Undergraduate Students
[ ] High School Students
- Project Description: The Chemistry and Dynamics Branch
of the Science Directorate at NASA Langley Research Center conducts
research into the trace constituent composition of the troposphere and stratosphere. Atmospheric
trace constituents, such as ozone, carbon dioxide, hydrocarbons and aerosols are present in only small
concentrations, but can have a large impact on climate, air quality, and atmospheric structure and
dynamics. The trace constituent composition of the troposphere and stratosphere is governed by
physical, chemical, and radiative processes of the Earth System in addition to natural and
anthropogenic emissions. Research utilizes observations from satellite instruments, field missions,
and ground observations, in addition to a variety of atmospheric models, to both understand the
current state and predict the future state of atmospheric composition. We are currently involved in
several interrelated research activities. We are engaged in box model studies of field mission data to
test our understanding of atmospheric photochemical processes. We participate in the NASA Global
Modeling Initiative, which is an effort to create and utilize a suite of related Earth System Modeling
Framework (ESMF) compliant global composition models. We are engaged in validation of observations
made by instruments on board the NASA Aura satellite using noncoincident modeling techniques. Last, we
are using the Langley Research Center's Real-time Air Quality Modeling System (RAQMS), a chemical data
assimilation system, for air quality analysis, scientific studies, and field mission chemical
forecasting support.
Desired Majors: Atmospheric Modeling, Data Analysis, and Assimilation
Key Words: Atmospheric Composition; Tropospheric Chemistry; Stratospheric Chemistry; Satellite
Atmospheric Observations
Point of Contact: Jassim Al-Saadi, J.A.Al-Saadi@nasa.gov, 757-864-5164
This project can be adapted for:
[X] Post-Doc
[X] Faculty
[X] Graduate Students
[ ] Undergraduate Students
[ ] High School Students
- Project Description:
The International Reference Ionosphere (IRI) model is a widely used empirical model for the
specification of ionospheric parameters and is recommended for international use by the Committee On
SPace Research (COSPAR) and the International Union of Radio Science (URSI). It provides monthly
averages of the electron and ion densities and their corresponding temperatures from about 50 km to
2000 km, as well as the Total Electron Content (TEC) and some additional parameters like the vertical
ion drift at the equator. For COSPAR, the international umbrella organization for space agencies, the
primary interest in IRI is the need for a general description of the ionosphere for the evaluation of
environmental effects on spacecraft and experiments, and humans in space. URSI, representing
telecommunication interests and general radio wave propagation issues, is primarily interested in the
IRI electron and ion densities for defining the background ionosphere for radio wave propagation
studies and applications.
An important functionality of the IRI model needed for space-weather-related applications is the
accurate characterization of ionospheric parameters during solar-geomagnetic storms. The recent
release of IRI-2000 is the first version of IRI to include any geomagnetic activity dependence, but
only for the F-region densities.
Currently there is no storm-time correction to IRI parameters in the E-region. TIMED/SABER
observations suggest several orders of magnitude enhancement in the E-region dominant ion (i.e., NO+)
and electron densities during the April 2002 and October-November 2003 solar storms. An error of
several orders of magnitude in the IRI E-region parameterization will limit the model's usability in
radio wave propagation models - as applied to system design of communication, navigation, and
surveillance systems - and the real-time processing of the radio wave propagation data during
solar-geomagnetic storms. To improve the utility and range of applicability of the IRI model, we
propose through this project to develop an empirical storm-time correction to the E-region NO+ and
electron densities using infrared emission measurements from the TIMED/SABER instrument.
Qualified applicants will have the opportunity to participate in a research project to examine how
satellite data can be used to explore the effects of solar-geomagnetic storms on the lower ionosphere
and produce an empirical model that will help accurately specify conditions in the lower ionosphere
for all space technologies that use radio waves traveling through the ionosphere, e.g., Earth
climate-related observations from space.
Desired Majors: Use of Satellite data in Study of the E-region
Key Words: Ionosphere, NO+, electron density, ionospheric E-region
Point of Contact: Christopher Mertens, Christopher.J.Mertens@nasa.gov, 757-864-2179
This project can be adapted for:
[X] Post-Doc
[ ] Faculty
[ ] Graduate Students
[ ] Undergraduate Students
[ ] High School Students
Branch Brief Description:
The Climate Science Branch
studies observations from satellite instruments to improve the understanding of clouds, aerosols,
ozone, and the Earth's radiation balance. They also advance computer models that simulate cloud
processes. Other research activities include converting satellite data into measurements useful to the
renewable energy community and testing the accuracy of satellite measurements through field
experiments.
- Project Description:
Basic and applied research is being conducted in remote sensing of the Earth's cloudiness and
radiative fluxes (top of atmosphere, surface, within atmosphere). Clouds are the primary modulators of
the radiative energy balance of the Earth's surface and atmosphere on both local and global scales.
Data sets from several satellite instruments, including CERES, ERBE, MODIS, CALIPSO, CloudSat, MISR,
Geostationary Operational Environmental Satellite, Landsat, AVHRR, HIRS, SSM/I, will be analyzed and
compared. In addition, simultaneous aircraft and/or ground-based laser-radar measurements (.e.g. ARM)
will be used to examine cloud cover, cloud base and top height, optical depth, reflectance, cloud
particle size, liquid and ice water path, and emissivity. Comparisons will be made with theoretical
predictions of cloud generation/dissipation and with models of cloud radiative properties such as
cloud albedo, bidirectional reflectance, and emissivity. Simulation studies will examine the sampling
requirements and cloud measurement capabilities of current and future satellite measurement systems.
Use of passive and active microwave observations are of special interest in addressing the problems
associated with multilayered cloud systems. Studies are also encouraged that analyze cloud data as
large ensembles of cloud systems or "cloud objects": a Lagrangian analog to the more traditional
Eulerian monthly averaged gridded climate data. Cloud studies of this sort include attempts to
unscramble changes in cloud dynamics from aerosol effects on clouds, i.e. the aerosol indirect effect.
Opportunities also exist for using high spectral resolution (monochromatic) algorithms to develop and
refine rapid radiative transfer (RRT) algorithms. Because of their high efficiency, the RRT
algorithms can be applied to the analysis and validation of large satellite data sets. In addition to
being used to create the RRT algorithms, the monochromatic algorithm is also being used to investigate
the radiative impacts of observed changes to trace gas abundances, as well as to changes in the cloud
and aerosol properties (e.g., amount and distribution). Finally, the monochromatic algorithms are
being used in a study to determine the optimal spectral regions for future satellite instruments.
Desired Majors: Satellite, Aircraft, and Ground Observed Cloud and Radiative Flux Analyses
Key Words: Atmospheric radiation; Atmospheric remote; Clouds; Lidar; Satellite atmospheric
observations; Microwave remote sensing
Point of Contact: Bruce Wielicki, Bruce.A.Wielicki@nasa.gov, 757-864-1273
This project can be adapted for:
[X] Post-Doc
[X] Faculty
[X] Graduate Students
[ ] Undergraduate Students
[ ] High School Students
- Project Description: Basic and applied research is being conducted in the development of
advanced techniques for retrieving and analyzing atmospheric data from satellite, airborne, and
ground-based remote-sensing instruments. Techniques are being developed (limb scattering, e.g.) for
processing satellite atmospheric limb scattering and laser-radar measurements and data from existing
satellite solar occultation experiments (SAM II, SAGE, SAGE II, and SAGE III), and various LIDAR
measurements. Our goal is to retrieve stratospheric and tropospheric constituent concentration
profiles and study their influence on atmospheric chemistry and dynamics. Current investigations
include the retrieval of tropospheric and stratospheric water vapor, ozone, nitrogen dioxide, and
aerosol information from solar extinction and LIDAR data; an assessment of the errors associated with
the determination of global ozone trends using solar occultation measurements from satellites; the
measurement of atmospheric constituent absorption cross sections at various visible wavelengths for
use in converting constituent extinction to concentration information; and the determination of
various aerosol optical properties from multiwavelength data.
Desired Majors: Inversion and Analysis of Remote-Sensing Data
Key Words: Aerosols; Atmospheric chemistry; Atmospheric moisture; Atmospheric ozone; Atmospheric
remote sensing; Lidar; Satellite atmospheric observations; Stratosphere; Troposphere
Point of Contact: Chip Trepte, Charles.R.Trepte@nasa.gov, 757-864-5836
This project can be adapted for:
[X] Post-Doc
[X] Faculty
[X] Graduate Students
[X] Undergraduate Students
[ ] High School Students
- Project Description:
The Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) satellite mission is
a joint mission between NASA and the French Space Agency, CNES. CALIPSO provides new insight into the
roles that clouds and atmospheric aerosols play in regulating Earth's climate, weather, and air
quality. CALIPSO was launched in April 2006 and orbits in the Afternoon (A-Train) Constellation which,
besides CALIPSO, includes Aqua, CloudSat, Parasol, and Aura. The CALIPSO payload consists of a lidar
that measures aerosols backscatter at 532 and 1064 nm and depolarization at 532 nm, an Infrared
Imaging radiometer (IIR) operating at 8.65, 10.6, and 12.0 m, and a single channel visible Wide Field
of View Camera (WFC) operating at 645 nm. The lidar profiles provide information on the vertical
distribution of aerosols and clouds, cloud ice/water phase, and a qualitative classification of
aerosol size (via the wavelength dependence of the backscatter). The IIR provides information on
cirrus particle size and the WFC provides meteorological context and a means to accurately register
CAIPSO observations to those from MODIS on the Aqua satellite. These observations complement active
and passive measurements made from other sensors within the A-Train to enable an even greater
understanding of our climate system.
Qualified candidates are invited to participate in CALIPSO activities that include evaluating
instrument performance and data quality using correlative measurements from recent field experiments
(eg, CC-VEx, NAMMA, TexAQS/GoMACCS) or through other observing activities, developing new algorithms
or approaches to derive aerosol and cloud optical and microphysical properties using both active and
passive remote sensing capabilities, and contributing to scientific investigations that integrate
CALIPSO measurements with other ground-based, airborne, or satellite data sets to examine or model
aerosol and cloud properties. It is anticipated that the candidate would work with the LaRC CALIPSO
team. Candidates with prior experience in remote sensing data analysis and/or aerosol/cloud modeling
are preferred.
Desired Majors: Lidar and Satellite Data Analysis, Aerosol/Cloud Modeling
Key Words: Lidar, remote sensing, cloud, aerosol
Point of Contact: Chip Trepte, Charles.R.Trepte@nasa.gov, 757-864-5836
This project can be adapted for:
[X] Post-Doc
[X] Faculty
[X] Graduate Students
[ ] Undergraduate Students
[ ] High School Students
- Project Description: Our group is leading the development of NASA's most advanced passive infrared
sensors for the study of Earth's climate and energy balance. In particular we have developed the
Far-Infrared Spectroscopy of the Troposphere (FIRST) instrument that is capable of observing the
entire thermally significant infrared spectrum from 6 to 100 micrometers wavelength. FIRST is a
Fourier Transform Spectrometer (FTS) instrument with a nominal spectral resolution of 0.625
wavenumbers. FIRST has flown twice on high altitude balloon platforms and will be deployed to Barrow,
AK, Mauna Loa, HI, Atacama Desert, Chile, and possibly the South Pole Station in Antarctica over the
coming years. FIRST makes fundamental measurements relevant to the Earth's greenhouse effect and
climate impacts of cirrus and water vapor.
We are also presently developing the In-Situ Net Flux within the Atmosphere of the Earth (INFLAME)
instruments. These are low-resolution FTS instruments designed to measure directly the net flux of
visible and infrared radiation within the atmosphere. INFLAME will fly on an Uninhabited Aerial
Vehicle (UAV) in 2008, recording the vertical profile of visible and infrared net radiative flux
within the atmosphere. The vertical derivative of this profile provides the net flux divergence, and
thereby the net heating rate within the atmosphere.
Members of the group are also involved in the NASA CERES, AIRS, and SABER experiments.
This position will involve the incumbent directly in all aspects of these projects - hardware
development and field deployment; data analysis; development of scientific and technical requirements
for future satellite sensors; and publication of results at scientific symposia.
Desired Majors: Hyperspectral Remote Sensing of the Atmosphere
Key Words: Hyperspectral Sensing; Spectroscopy; Energy Balance; Radiative Fluxes; Satellite Remote
Sensing
Point of Contact: Marty Mlynczak, M.G.Mlynczak@nasa.gov, 757-864-5695
This project can be adapted for:
[X] Post-Doc
[ ] Faculty
[ ] Graduate Students
[ ] Undergraduate Students
[ ] High School Students
- Project Description:
NASA Langley Research Center (LaRC) recently developed an airborne High Spectral Resolution Lidar
(HSRL) to measure aerosol and cloud distributions and optical properties. The HSRL technique takes
advantage of the spectral distribution of the lidar return signal to discriminate aerosol and
molecular signals to independently retrieve aerosol extinction and backscatter. The current LaRC
airborne HSRL measures aerosol backscatter and depolarization at 532 and 1064 nm and aerosol
extinction at 532 nm. The HSRL along with the Langley Oxygen A-band Spectrometer (LAABS) and a newly
developed Hyperspectral Polarimeter (HySPAR) have recently been successfully deployed on the MILAGRO
and 2006 TexAQS/GoMACCS field campaigns as well as a series of CALIPSO validation flights. Flights
from these field campaigns were coordinated with overpasses of A-Train and Terra satellite remote
sensing instruments (CALIOP, MODIS, MISR, etc.) and other aircraft deploying in situ and remote
sensing instruments that measured aerosol optical and/or microphysical properties. The data sets
acquired offer extensive and unique opportunities to study the distribution of aerosol and explore
combined active-passive retrievals of aerosol microphysical properties and techniques for inferring
aerosol composition/type. These retrievals would address both current and future space-based (e.g.
CALIPSO, MODIS, MISR, GLORY) and airborne (HSRL, HySPAR, LAABS, RSP) measurements. In addition, LaRC
is currently developing an advanced HSRL instrument which will include additional wavelengths in the
UV to provide measurements of ozone via the DIAL technique and aerosol extinction and backscatter at
355 nm. The addition of the UV extinction and backscatter measurements to the measurements at 532 and
1064 nm will provide data to explore advanced retrievals of aerosol microphysical parameters.
An opportunity exists for qualified candidates to participate in the airborne HSRL activities that
include evaluating instrument performance and data quality, developing new algorithms or approaches to
derive aerosol optical and microphysical properties, and contributing to the scientific analyses of
current data sets that integrate measurements from other participating aircraft and satellite
platforms. It is also anticipated that the candidate would deploy with the LaRC team on future field
campaigns to participate in real-time and post flight analyses of the airborne HSRL data and form
collaborations with investigators from other platforms and the modeling community on the use and
interpretation of the airborne HSRL data. Candidates with prior experience in lidar data analysis and
system design/operation are preferred.
Desired Majors: Physical Sciences, Engineering, Mathematics, Computer Science
Key Words: Atmospheric Composition; Lidar; Active Remote Sensing; Aerosols; Clouds; Radiation;
Aerosol Microphysics; Ozone
Point of Contact: Chris Hostetler, Chris.A.Hostetler@nasa.gov, 757-864-5373
This project can be adapted for:
[X] Post-Doc
[X] Faculty
[X] Graduate Students
[ ] Undergraduate Students
[ ] High School Students
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