Variation of snow water resources in northwestern China, 1951-1997

An observation study is carried out on snow mass amount estimate in northwe stern China by using microwave derived snow depth charts employing data fro m SMMR in conjunction with daily snow depth, density and snow cover duratio n records for 46 ground climate stations. Spatial patterns, seasonal cycle, and interannual variation of snow cover are discussed. Results show that s now cover is the second largest water supply over the arid northwestern Chi na, and unlike most other areas in the world, northwestern China did not ex perience any decrease in snow cover since 1987. Secular trends reveal syste matic increase in snow mass and durations. Analysis of snow cover-climate r elationship indicates that gradual increase in snow cover is primarily in r esponse to increase in snow season precipitation.