Determination of characteristic features of cloud liquid water from satellite microwave measurements
- Univ. of Colorado, Boulder (United States)
In this paper the authors present an algorithm for determining liquid water path (LWP) in clouds using satellite microwave measurements from the special sensor microwave/imager (SSM/I). This physically based algorithm is derived using the guidance of a 32-stream plane-parallel model of microwave radiative transfer in the cloudy atmosphere. Their investigation using both radiative transfer model and observed SSM/I data indicates that the retrieved LWP is sensitive to the emission temperature of the liquid water, to the presence of large hydrometeors, to the nonuniformity of the rainfall in the satellite field of view, and to the radiation from atmosphere and ocean. Therefore they have incorporated cloud temperature into their algorithm using ancillary infrared satellite data. To account for the effects of rainfall on the LWP retrievals, they use a threshold for the onset of precipitation to determine whether there is any precipitation in the satellite field of view. Two separate retrieval schemes are derived for non-precipitating and precipitating clouds. A clear-sky radiation scheme is developed to separate radiation of atmosphere and ocean from that of liquid water. This algorithm is indirectly validated by comparing retrieved values of LWP for clear versus cloudy situations. The retrievals are examined for regions in the tropical western Pacific Ocean, the North Atlantic Ocean, and the subtropical southeast Pacific Ocean. The retrievals obtained using their algorithm are also compared with simultaneous retrievals using other LWP algorithms described in the literature. The present algorithm is shown to perform consistently well in all three regions under all conditions. It is determined that features of their algorithm that result in more consistent global retrievals of LWP are inclusion of the tunable clear-sky scheme, estimation of cloud temperature using satellite infrared radiances, and consideration of precipitation. 31 refs., 20 figs., 3 tabs.
- OSTI ID:
- 6889400
- Journal Information:
- Journal of Geophysical Research; (United States), Journal Name: Journal of Geophysical Research; (United States) Vol. 98:D3; ISSN JGREA2; ISSN 0148-0227
- Country of Publication:
- United States
- Language:
- English
Similar Records
Observations of cloud liquid water path over oceans: Optical and microwave remote sensing methods
Aircraft observations of the vertical structure of stratiform precipitation relevant to microwave radiative transfer
Related Subjects
540120* -- Environment
Atmospheric-- Chemicals Monitoring & Transport-- (1990-)
ALGORITHMS
ATLANTIC OCEAN
CLOUDS
EMISSION
FLUIDS
HYDROGEN COMPOUNDS
ICE
LIQUIDS
MATHEMATICAL LOGIC
MICROWAVE SPECTRA
OXYGEN COMPOUNDS
PACIFIC OCEAN
PERFORMANCE
PRECIPITATION
REMOTE SENSING
SATELLITES
SEAS
SEPARATION PROCESSES
SKY
SPECTRA
SURFACE WATERS
WATER