M. Klein et Aj. Gasiewski, Nadir sensitivity of passive millimeter and submillimeter wave channels toclear air temperature and water vapor variations, J GEO RES-A, 105(D13), 2000, pp. 17481-17511
The upwelling microwave-to-submillimeter wave brightness temperature observ
ed from above the Earth's atmosphere is sensitive to parameters such as pre
ssure, temperature, water vapor, and hydrometeor content, and this sensitiv
ity has been successfully used for passive vertical sounding of temperature
and water vapor profiles. To determine optimal satellite observation strat
egies for future passive microwave instruments operating at frequencies abo
ve those now used, a study of the potential clear-air vertical sounding cap
abilities of all significant microwave oxygen and water vapor absorption li
nes in the frequency range from approximately 10 to 1000 GHz has been perfo
rmed. The study is based on a second-order statistical climatological model
covering four seasons, three latitudinal zones, and altitudes up to simila
r to 70 km. The climatological model was developed by comparing data from t
hree sources: the Upper Atmosphere Research Satellite Halogen Occultation E
xperiment (UARS HALOE) instrument, the TIROS Operational Vertical Sounder (
TOVS) Initial Guess Retrieval radiosonde set, and the NOAA advanced microwa
ve sounder unit (AMSU) radiosonde set. The Liebe MPM87 absorption model is
used for water vapor and oxygen absorption and considers the effects of ozo
ne and isotope absorption. Variations in the vertical sounding capabilities
due to statistical variations of water vapor and temperature with latitude
and season around each line are considered, and useful channel sets for ge
ostationary microwave vertical sounding are suggested.