Principal Investigator: Dr. Christian D. Kummerow, NASA Goddard Space Flight Center
Proposal Title: A small, lightweight radiometer to improve the temporal sampling of rainfall
Rainfall, along with temperature are undoubtedly the variables which will most directly affect mankind in an era of changing climate. The transient nature of rainfall, however, makes the detection of subtle changes difficult. While the successful launch and early operation of the joint US/Japan TRMM mission will yield the first systematic maps of global rainfall and the distribution of latent heating, TRMM cannot solve all the problems associated with precipitation. The biggest shortcoming of TRMM, as well as previous and future single satellite missions, is that the poor sampling of the instruments severely limits the number of applications that could be envisioned. With better sampling, rainfall climatologies could be monitored on finer scales, data assimilation and weather forecast models could be initialized properly, surface hydrology applications such as soil moisture and flash flood predictions would be possible. A proposal from Goddards Laboratory for Atmospheres has been submitted to NASAs EOS Response to RFI on Concepts for Science and Applications Missions in the Post-2002 Era.
The main objectives of the proposed work is to develop a microwave radiometer that is light enough, small enough and cheap enough to allow multiple copies to be flown concurrently in order to overcome the serious rainfall sampling limitations of the state-of-the art radiometers flying on EOS-PM, ADEOS-II and eventually the NPOESS series. Specifically, we consider two alternative designs. The main approach is a new and smaller (26 kg, 41W) sensor that combines a scanning mirror at 37 and 85 GHz with a thinned array 10.7 GHz channel that could be mounted on a RSDO low-range three-axis stabilized bus. We are proposing to build a prototype instrument to test the robustness of the design as well as sensitivity and noise. Concurrent with this main effort, however, we also plan to review the design heritage of the hugely successful SSM/I instrument to determine if mass and power requirements can be reduced to those of the first option.