Progress on Observation of Cryospheric Components and Climate-Related Studies in China
- Manuscript received: 2008-03-10
- Manuscript revised: 2008-03-10
Abstract: Systematic studies on the cryosphere in China started in the late 1950s. Significant achievements have been made by continuous investigation of glacier inventories, frozen ground observations, paleo-climate analyses of ice cores, process studies and the modeling of cryopsheric/atmospheric interactions. The general facts and understanding of these changes include: (1) Solid precipitation, including the number of days with frost and hail storms, shows a decreasing tendency over the past half century. (2) In most areas glaciers are retreating or have completely vanished (>80%), some glaciers are still advancing (5%--20% depending upon time period). The annual glacial melt water has been increasing since the 1980s. This increased supply of melt water to river runoff in Northwest China is about a 10%--13%. (3) The long-term variability of snow cover in western China is characterized by a large inter-annual variation superimposed on a small increasing trend. Snow cover variability in the Qinghai-Xizang Plateau (QXP) is influenced by the Indian monsoon, and conversely impacts monsoon onset and strength and eventually the drought and flood events in middle-low reaches of Yangtze River. (4) Frozen ground, including permafrost, is decaying both in QXP and in Northeast China. The most significant changes occurred in the regions with thickest seasonal frozen ground (SFG), i.e., inland QXP, then northeastern and northwestern QXP. The cold season air temperature is the main factor controlling SFG change. The increase of ground surface temperatures is more significant than air temperature. (5) The sea ice coverage over the Bohai Sea and Yellow Sea has deceased since the 1980s. (6) River ice duration and ice thickness is also decreasing in northern China. In 2001, the Chinese National Committee of World Climate Research Program/Climate and Cyosphere (WCRP/CliC) (CNC-CliC) was organized to strengthen research on climate and cryosphere in China. Future monitoring of the cryosphere in China will be enhanced both in spatial coverage and through the use of new techniques. Interactions between atmosphere/cryosphere/ hydrosphere/land-surface will be assessed to improve our understanding of the mechanisms of cryospheric change.