Influences of Climate Warming on Plant Phenology in Qinghai Plateau

Long period data observed at selected meteorological stations are analyzed to investigate the response of plant phonology to climate warming in Qinghai Plateau. The Plteau is divided into eastern agriculture region, around Qinghai Lake region, source of three rivers and Qaidam Basin, with their representative areas of Huangyuan, Menyuan, Qumalai and Delingha, and the analysis period is 1983—2007, 1987—2007, 1997—2007 and 1987—2007 respectively. Monthly and annual mean temperature, precipitation, plant development period and other related data are analyzed statistically, showing that annual temperature increases in all of the 4 regions with the ratio of 0.61℃/10 a, 0.59℃/10 a, 1.52℃/10 a, 0.62℃/10 a respectively. Annual precipitation of around Qinghai Lake region shows a decreasing trend, and the value is-11.58 mm/10 a. Annual precipitation of eastern agriculture region, source of three rivers and Qaidam Basin increases by 0.86 mm /10 a, 107.37 mm /10 a and 12.95 mm /10 a respectively. The date of turning green in Qaidam Basin region has delayed by 8.2 d, but in eastern agriculture region, around Qinghai Lake region and source of three rivers it is 8.6 d, 10.5 d and 9.8 d earlier than before. In these 4 regions the flowing stage are respectively 3.2 d, 7.8 d, 1.7 d and 10.9 d earlier. The yellow stage is respectively 6.5 d, 16.2 d, 6.6 d and 6.2 d later, so the plant growth stage is extended in the eastern agriculture region, around Qinghai Lake region and the source of three rivers, but the plant growth stage is shortened a little in Qaidam Basin. The changing tendency of turning green data and yellow stage is found well correlated with annual mean temperature. There are many factors affecting the flowing of plant, so the correlation between plant flowing and mean annual temperature is less significant. The annual precipitation and stage precipitation have some influences on key periods of plant growing, but the influences are less important compared with the temperature.