Study of the sensitivity of a regional model in response to land cover change over northern China

✍ Scribed by Helin Wei; Congbin Fu

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 570 KB
• Volume: 12
• Category: Article
• ISSN: 0885-6087
• DOI: 10.1002/(sici)1099-1085(19981030)12:13/14<2249::aid-hyp733>3.0.co;2-q

✦ Synopsis

Changing land surface types may have important consequences for the climate system. Predicting even the local, immediate eects of changing land surface types on the local energy and water balance has been dicult, because the land surface parameterization schemes used previously in climate models have been inadequate and the resolution of GCMs (global circulation models) has been too coarse to describe mesoscale forcings such as vegetation gradient adequately and to yield accurate regional climate detail. Grassland is a major ecosystem in northern China, playing a crucial role in the surface energy and water budget. Inclusion of a biosphere and atmosphere transfer scheme (BATS) into the National Centre for Atmospheric Research (NCAR) regional climate model (RegCM) permits an exploratory study of the possible eects of land cover change. Based on the observation of deserti®cation processes in this area, an experiment with seven-day integration was designed in which all of the grassland in northern China is replaced by desert. The results show that, with the conversion of grassland into the desert, the surface hydrological cycle over northern China is weakened, with less precipitation and, in particular, a reduction in evaporation; the surface heat budget also changes, especially with the reduction in latent heat ¯ux being much more than the reduction of net radiation, which results in an increase in surface temperature. These results are relevant to changes of parameters in BATS owing to changing land surface. Some detailed patterns of the eects of changing land surface on local energy and water balance have been simulated.