摘要:

The extent of the snow cover, the stored amount of water and the state of the snow metamorphism, in particular the date of the snow-melt and the intensity of the run-off, are of prime importance to hydrology and water management in large regions as well as to weather and climate. Regular observations by satellite-borne sensors can substantially improve the information on the status and the dynamic behaviour of these hydrologic parameters on a global scale. Microwave radiometers or scatterometers as all-weather and day and night sensors are excellent tools for reliable observations of cloud-covered regions of the world. The interaction of microwaves with snow strongly depends on snow wetness and size and structure of snow grains. Multifrequency observations can be used to classify snow conditions, to estimate the water equivalent or dry snow and to determine the start of the melting period. Results of several years of ground-based microwave observations along with classical hydrologic measurements are discussed and experience with satellite-borne microwave radiometers for the determination of the extent and state of the northern hemispheric snow cover is reported. Conclusions are drawn to define optimum sensor specifications for satellite-borne microwave remote sensing of the snow cover.

ISSN:0143-1161    

DOI:10.1080/01431168308948536

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

The potential for retrieving cloud amount data from satellite-derived radiation budget archives is investigated. A predictive relationship between cloud cover and satellite-derived system albedo is established and used to produce a new oceanic cloud climatology. In view of the spatially and temporally discontinuous nature of cloud data and the diverse requirements of the three major users (i.e. scientists concerned with weather forecasting, environmental remote sensing and climate modelling), the following recommendations are made: (1) Radiance data, not cloud data, should be archived directly from satellite observations. (2) The highest spatial and temporal resolutions available should be retained in the archive. (3) Detailed comparative studies between surface and satellite assessments of cloud climatologies should be undertaken.

ISSN:0143-1161    

DOI:10.1080/01431168308948537

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor