Trends in temperature and precipitation on the Tibetan Plateau, 1961-2005

We studied the basic characteristics of temperature and precipitation in different climatic zones of the Tibetan Plateau (TP) from 1961-2005, through statistical and spatial analysis. Over the past 45 yr, annual temperature in the TP increased at a rate of 0.265 degrees C decade(-1). The rate of temperature increase in winter was double that of spring in almost all zones and the rate of annual temperature increase was demonstrably higher during 1980-2005 than during 1961-1980 and 19612005, suggesting that the rate of warming is accelerating. Annual precipitation showed a slight increase (8.21 mm decade(-1)) across the whole TP. Short (2 to 4 yr), middle (5 to 8 yr), and long (> 10 yr) precipitation cycles were found at 32, 11, and 6 stations, respectively. Empirical Orthogonal Function (EOF) analysis revealed different precipitation cycles between the northern and the southern TP, with the boundary along 33 degrees N. For the period 1961-2005, 46 stations showed a warming-wetting trend; the number of stations showing this trend for 1980-2005 was 34% higher than for 1961-1980, suggesting that a warming-wetting trend will dominate the TP in the future.