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 emission, 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.

Past and ongoing NASA aircraft campaigns provide an extensive data base of in situ observations. These observations comprise some of the most complete characterizations of tropospheric composition ever obtained. Through ongoing instrument development and deployment across the global the number of trace gas species measured in the troposphere continues to increase and instruct. Satellite observations from NASA satellites as well as international partners include observations of carbon monoxide, ozone, NO2, CH2O, and other important tropospheric trace constituents. These satellite measurements provide long-term global coverage and will include hourly observations over selected parts of the globe in the near future. 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 that will increase our knowledge of tropospheric composition and chemical cycles through new or improved measurements of tropospheric trace gases and/or through 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.

Location:
Langley Research Center
Hampton, Virginia

Field of Science:Earth Science

Advisors:
Gao Chen
gao.chen@nasa.gov
757-864-2290

James H. Crawford
James.H.Crawford@nasa.gov
757-864-7231

Joshua P. DiGangi
joshua.p.digangi@nasa.gov
(757) 864-8789

John B. Nowak
john.b.nowak@nasa.gov
757-864-7470

Eligibility is currently open to:

• U.S. Citizens;
• U.S. Lawful Permanent Residents (LPR);
• Foreign Nationals eligible for an Exchange Visitor J-1 visa status; and,
• Applicants for LPR, asylees, or refugees in the U.S. at the time of application with 1) a valid EAD card and 2) I-485 or I-589 forms in pending status

• Degree: Doctoral Degree.