PROGRAM TITLE:	Mission Operations and Data Analysis 
ACTIVITY STREAM:	Data and Observations
SCIENCE ELEMENT:	Climate and Hydrologic Systems
				Biogeochemical Dynamics
				Ecological Systems and Dynamics
				Earth System History
				Solid Earth Processes
				Solar Influences
				Global Observing Systems


SCIENTIFIC MERIT:  The objective of the Mission Operations and Data 
Analysis program is to acquire, process, and archive long-term data 
sets produced by spaceborne missions, which are funded by other 
programs until they are launched. These data relate to issues of 
global change in atmospheric ozone and trace chemical species, the 
Earth's radiation budget, aerosols, sea ice, land surface properties, 
and ocean circulation and biology.
SAM-II and SAGE-2	The Stratospheric Aerosol Measurement II 
(SAM-II) instrument on the Nimbus-7 satellite will conclude its 
measurements in December, 1993, having collected  a 15-year data 
set on atmospheric aerosols (and stratospheric clouds) in Earth's 
polar regions. Data from the Stratospheric Aerosol and Gas 
Experiment II (SAGE-II), on NASA's Earth Radiation Budget 
Spacecraft (ERBS), continue to provide vertical profiles of aerosols, 
ozone, nitrogen dioxide, and water vapor over Earth's tropical and 
mid latitude regions, as they have since ERBS launch in 1984.
ERBS 	The Earth Radiation Budget Experiment (ERBE), is 
composed of three identical instrument packages flying on NOAA-9, 
NOAA-10, and NASA's ERBS. These instruments provide data 
illuminating the temporal and spatial variations in the Earth's 
radiation budget, which drive the Earth's climate, as they have since 
the launch of ERBS in 1984. Data from the Earth Radiation Budget 
(ERB) instrument on Nimbus-7, and from the ERBE instruments, 
provide the only continuous data set on total solar irradiance ("solar 
constant") and its temporal variations stretching from 1978 to the 
present.  NOAA 9  and 10 operations continue to support ERB  non-
scanner measurements.   ERB measurements onboard Nimbus 7 will 
conclude in December 1993 due to the deterioration of the satellite's 
orbital geometry.
ASF 	SAR data transmitted from ESA's ERS-1 spacecraft is acquired, 
processed, and archived by NASA's Alaska SAR (Synthetic Aperture 
Radar) Facility (ASF), based at the Geophysical Institute, University 
of Alaska, Fairbanks.  ASF is doing the same with SAR data from 
Japan's ERS, and is planning to support ESA's ERS-2, and Canada's 
RadarSat spacecraft when they become operational. These data 
provide important information on the properties and dynamics of sea 
ice and other land and sea processes in the polar regions.
SIR-C	The Spaceborne Imaging Radar-C (SIR-C) builds upon the 
heritage of spaceborne synthetic aperture radar (SAR) missions 
Seasat SAR (1978), SIR-A (1981) and SIR-B (1984) in the use of SAR 
technology to study earth science. Because of SAR's ability to image 
the earth through cloud cover, sensitivity to surface roughness, soil 
moisture, and ice-water contrast, it is useful in studies of geological 
features. canopy morphology, sea ice dynamics,  and ocean surface 
features.  SIR-C provides the opportunity to identify the optimum 
wavelengths, polarizations, and illumination geometries for SAR 
imagery of the earth.
Ocean Color	NASA will purchase, from the Orbital Sciences 
Corporation (OSC), ocean color data to be acquired by the SeaWiFS 
instrument which will fly on the SeaStar satellite to be launched in 
July, 1994.  SeaWiFS will provide worldwide high-precision, 
moderate-resolution, multispectral visible observations of ocean 
radiance, thus building on the experience gained from the Coastal 
Zone Color Scanner (CZCS) on Nimbus-7. These data should determine 
the mean and variable bio-optical reflectance characteristics of the 
upper ocean, leading to an understanding of the primary 
productivity of the upper oceans and the affected fluxes of carbon 
dioxide and other trace gases across the air-sea interface. MO&DA; 
will fund the acquisition, processing, and archiving of resulting long-
term data sets.
STAKEHOLDERS:  National and international connections are a natural 
part of this program. There are ongoing interagency connections with 
NOAA and international agreements with ESA, Japan, and Canada.  
International agreements provide that the Alaska SAR Facility will 
acquire SAR data from satellites flown by ESA (the European Space 
Agency), Japan, and Canada. SIR-C is a joint mission with a European 
consortium consisting of the DLR (Germany) and ASI (Italy); the 
consortium is referred to as X-SAR in reference to the X-band radar 
sensor they are contributing to the SIR-C/X-SAR experiment. 
Nationally, the SIR-C Science Team includes members representing 
the USGS and USDA.
Demand for SeaWiFS ocean color data is expected to be led by the 
Joint Global Ocean Flux Study (JGOFS), part of a core program of the 
International Geosphere-Biosphere Program (IGBP). Other 
multinational studies that will rely on ocean color data include the 
World Ocean Circulation Experiment (WOCE) and the International 
Global Atmospheric Chemistry (IGAC) program.
POLICY RELEVANCE:	Climate Change and Natural Variability
				Forests and Deforestation
PROGRAM CONTACT:	Mr. Stanley Schneider
Chief, Mission Operations and Data Analysis Branch
NASA Headquarters, Code YD
Washington, DC  20546