HR: 14:40h
AN: U13B-03 INVITED     [Abstracts]
TI: Challenges to Deriving Climate Time Series From Satellite Observations
AU: * Wentz, F J
EM: frank.wentz@remss.com
AF: Remote Sensing Systems, 438 First Street, Santa Rosa, CA 95401 United States
AU: Mears, C A
EM: mears@remss.com
AF: Remote Sensing Systems, 438 First Street, Santa Rosa, CA 95401 United States
AB: Satellites have been observing the Earth's weather and climate since the launch of TIROS-1 in 1960. As satellite and sensor technology advanced over the next two decades, the accuracy of the satellite observations improved to the point of being useful for climate monitoring. The launch of the first Microwave Sounding Unit (MSU) in October 1978 and the first Special Sensor Microwave Imager (SSM/I) in June 1987 mark the beginning of research-quality time series for several important climate state variables, including tropospheric temperature and water vapor, cloud and rain water, and ocean surface winds. In this talk, we will illustrate the many obstacles that must be overcome to convert raw satellite measurements into climate data records. Probably the most pivotal issue is sensor calibration. Although an on-board self-calibrating apparatus is part of each satellite sensor, the accuracy of the calibration system is limited and in some cases unexpected calibration problems occurred on-orbit. The lack of exact calibration leads to a second problem: merging sensors flying on many different satellites into one consistent decadal time series. Also drifts in the satellites' orbits, both in altitude and local time of day, must be carefully taken into account else spurious signals will enter the time series. In addition to these technical difficulties, programmatic problems present a different set of hurdles that must be overcome. The maintenance of a long-term climate record may necessitate sustaining a long-term research activity requiring continuity in both expert staffing and funding. The alternative of computing climate records in an operational rather than research environment creates a new set of problems. As the satellite sensor technology continues to advance into the next decade, new challenges will arise. The new sensors will have different channel sets, viewing geometries, and orbital characteristics. Their complexity will be an order of magnitude greater than their predecessors. Furthermore, the conflicting requirements of operational weather forecasting versus climate monitoring will continue to be a complication. We will need to overcome all of these problems in order to merge these new observations into a seamless half-century satellite climate record.
UR: http://www.remss.com
DE: 1610 Atmosphere (0315, 0325)
DE: 1616 Climate variability (1635, 3305, 3309, 4215, 4513)
DE: 1635 Oceans (1616, 3305, 4215, 4513)
DE: 1640 Remote sensing (1855)
SC: Union [U]
MN: Fall Meeting 2005