A Composite Observing System forAtmospheric Water Vapor

Rex J. Fleming

UCAR Joint Office for Scientific Support (JOSS)


Atmospheric water vapor is crucial to a range of socioeconomic applications in atmospheric science. No one observing system can provide the proper combination of accuracy, vertical resolution, and global coverage needed for the se applications. A composite observing system for atmospheric water vapor is emerging and these components are briefly described. New results and expectations from measurements on board commercial airlines are reviewed. Comparisons are made between the aircraft data and radiosondes. The ability of the commercial aircraft Water Vapor Sensing System (WVSS) to depict moist absolutely unstable layers (MAULs) is presented.

A variety of other observing systems will complete the composite system. Theadvantages and limitations of GPS slant path retrievals are reviewed. The roles of other observing systems such as ground-based remote sensing, remote sensing from commercial aircraft, and the use of UAVs are projected.