Organization: National Aeronautics and Space Administration (NASA)

Research Title: Radiation Science Program

Funding Level (millions of dollars):

FY94	6.5
FY95	9.6
FY96	6.0

Committee on Environment and Natural Resources (CENR) Component:
(a) Subcommittee: Global Change Research Subcommittee (100%)
(b) Environmental Issue: Climate change (100%)
(c) Research Activity: System structure and function: Understanding (100%)

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

Point of Contact:
Robert Curran
Phone: 202-358-1432
E-Mail: rcurran@hq.nasa.gov

Research Goals:
(a) To advance the understanding of radiative exchange processes in the sun-earth- atmosphere system. (b) To develop improved radiation models and parameterizations for earth system models. (c) To improve space observational capabilities for radiation parameters and processes.

Research Description:
The major research elements of the program are:

Clouds and Radiation - Through the First ISCCP Regional Experiments (FIRE) project, conduct comprehensive field measurements, data analysis, and modeling of the radiative characteristics and the formation, maintenance, and dissipation mechanisms of cirrus and marine stratocumulus clouds. Radiation studies include satellite, airborne, and surface measurements of broadband and multispectral radiation fluxes and lidar backscattering characteristics and development and testing of improved radiation parameterizations for regional and global climate models. Cloud process studies include the large-scale and local meteorological environments as well as microphysical processes. Observations for these studies involve existing satellite measurements and airborne and surface deployment of advanced technology remote sensors including lidars, wind profilers, Doppler radars, radiometers, and spectrometers. In addition, measurements are made of cloud microphysical characteristics from unique balloon sondes and conventional meteorological parameters from operational and special rawindsondes.

Aerosols and Radiation - Investigate aerosol radiative forcing mechanisms including the direct effects of aerosols in absorbing and scattering atmospheric radiation and the indirect aerosol effects whereby aerosols, acting as cloud condensation nuclei, modify cloud formation and decay processes and cloud radiative properties.

Remote Sensing Research - Evaluate the accuracy of current satellite measurement capabilities by using airborne and ground-based correlative measurements, to derive improved cloud and radiation data products from existing satellite data, and to define measurement requirements for future satellite systems. Airborne prototypes for future satellite instruments are developed and tested in regional experiments to derive new science results and to demonstrate the technology for future satellite systems.

Other Radiation Processes - Conduct studies to improve and test models for radiation budget components at the Earth's surface, to use these models and associated satellite observations in developing climatologies of surface radiation budget components, to understand and quantify solar variability as a radiative forcing mechanism for the Earth's climate system, and to identify radiation-dynamical interactions in large- scale meteorological systems.

Program Interfaces:
The Radiation Science Program is closely integrated with NASA Mission to Planet Earth flight programs through participation of the Program Manager as Program Scientist for appropriate instruments and missions. In addition a number of national and international scientific organization, panels, and working groups provide coordination and guidance for the program. FIRE, the largest program element, is a NASA-lead multi-agency program that is coordinated through an interagency working group of agency Program Managers from NASA, NSF, ONR, NOAA, and DOE. Scientific coordination and guidance is provided by a single FIRE Science Team composed of PI's supported by the various agencies. Coordination with the DOE's ARM Program is accomplished by NASA representation on the ARM Interagency Working Group. In addition, the program is periodically reviewed by the NAS Board on Atmospheric Science and Climate and by the World Climate Research Program's Working Group on Radiative Fluxes .

Program Milestones:
Spring 1995: Selection and initiation of FIRE-III Science Team. Summer 1995: Smoke Cloud and Aerosol Radiation (SCAR-B) experiment, Brazil (In collaboration with MODIS and Aerosol Interdisciplinary. Science Teams). Spring 1996: FIRE III Cirrus Mini- campaign (In collaboration with SASS). Spring 1997: FIRE III Arctic Field Campaign.

Policy Payoffs:
(a) Improved radiation parameterizations for regional and global climate models. (b) Better characterization of the formation, maintenance, and dissipation mechanisms of cirrus and marine stratocumulus clouds and improved methods for treating cloud processes in regional and global models. (c) More accurate algorithms for retrieving cloud and radiation data from satellite measurements. (d) New measurements of atmospheric aerosol radiative properties and aerosol-cloud modification effects. Special focus is on aerosols produced by biomass burning to reduce the large uncertainties of current estimates for aerosol radiative forcing of climate change.