Organization: National Aeronautics and Space Administration (NASA)

Research Title: Atmospheric Dynamics Research Program

Funding Level (millions of dollars):

FY94 11.6
FY95 7.9
FY96 5.5

Committee on Environment and Natural Resources (CENR) Component:
(a) Subcommittee: Global Change Research Subcommittee (95%); Natural Disaster Reduction Research Subcommittee (5%)
(b) Environmental Issue: Climate change (20%); Natural Variability, including seasonal-to-interannual forecasting (80%)
(c) Research Activity: System structure and function: Understanding (100%)

Organizational Component:
Physical Climate Branch, Science Division
Office of Mission to Planet Earth
NASA Headquarters
Washington DC 20546

Point of Contact:
Ramesh K. Kakar
Phone: 202-358-0240

Research Goals:
To improve our understanding of the physical processes affecting the energy and water cycles on scales ranging from that of the global circulation to small scale processes whose effects are felt both regionally as well as globally. Improved understanding will result in a better representation of atmospheric processes, particularly energy and water related processes in the General Circulation Models (GCMs). Currently the representation of these processes are a major source of uncertainty in the predictions from GCMs. To accomplish this research goal this program also pursues the development of ground, airborne and space-based remote sensing techniques for the measurement of meteorological parameters.

Research Description:
This program has three major components:

Remote Sensor Development (40%). Progress towards remote sensor requirements includes the development and refinement of ground and airborne lidars for measurement of temperature, moisture and pressure; airborne radars for measurement of precipitation; microwave radiometers for surface imaging and cirrus cloud properties, and the measurement of moisture, temperature, cloud properties, and precipitation; airborne lidars for the measurement of aerosol and cloud backscatter properties and wind velocity profiles; balloon and airborne infrared radiometers for improved sea surface measurements. All these activities are closely related to the development of the Office of Mission to Planet Earth flight sensors/missions such as TRMM (Tropical Rainfall Measuring Mission), AIRS (Atmospheric Infrared Sounder), AMSU (Advanced Microwave Sounding Unit), MHS (Microwave Humidity Sounder), MIMR (Multifrequency Imaging Microwave Radiometer) and LAWS (Laser Atmospheric Wind Sounder).

Data Analysis and Remote Sensing Algorithm Development (30%). This involves satellite data analysis, and calibration and validation of this data. This also involves participation in international and multi-agency coordinated field programs like TOGA-COARE and analysis of data obtained during these campaigns. During TOGA-COARE, NASA aircraft and instruments sponsored by this program participated in well coordinated flight operations with other agencies and measured convective activity in a variety of situations ranging from dissipating systems to actively building and large mature systems. Several NASA microwave radiometers on the ER-2 aircraft were recently used by NASA and Air Force investigators to calibrate and validate SSM/T2 satellite sensors under the sponsorship of this program.

Theory and Numerical Modeling (30%). Modeling undertakings of interest include study of mesoscale phenomenon and interscale energy transitions; and development of parameterization for moist convective systems, frontal zones, internal gravity waves, clouds and radiative transfer. The global distribution of rainfall is critically important in monitoring the global energy and water cycle. The heat released into the atmosphere by the phase change from vapor to liquid and subsequent fallout, i.e. precipitation, is an important element in the energy exchange in the general atmospheric system and critical in understanding the evolution of atmospheric systems from convection to cyclones.

Program Interfaces:
This program has strong links with other components of the NASA Atmospheric Sciences Branch, i.e. Radiation Processes, Water Cycle Processes and Physical Oceanography. It also has strong links with programs supported by other agencies, particularly NSF, NOAA and USAF.

Program Milestones:
Fall 1994: Validation of USAF sponsored SSM/T2 satellite with NASA airborne microwave radiometers. Winter 1994/1995: TOGA-COARE data archived and available through Internet. Summer 1995: Convection and Moisture Experiment (CAMEX) data analyzed and archived. Fall 1995: First deployment of airborne Doppler Lidar for measurement of wind fields in and around weather systems. 1996: Goddard Cumulus Ensemble model linked to NCAR /Penn State MM5 model.

Policy Payoffs:
The representation of atmospheric processes, particularly energy and water related processes, are a major source of uncertainty in the predictions from GCMs. Through observations and understanding of these processes this program will enable significant improvements in the reliability of GCM climate predictions.