Climate extremes in the Kobresia meadow area of the Qinghai-Tibetan Plateau, 1961–2008

The Alpine Kobresia meadow is a major vegetation type on the Qinghai-Tibetan Plateau in western China. It is important both in preserving local and regional water and carbon and as a valuable pasture resource; however, meadow degradation has been spreading under both climatic and human disturbance. Climate extremes and related disasters are more discernible by local people than gradual trends and may have rapid and direct impact on the ecosystem; however, research on the resilience of the Kobresia meadow is rare. This study uses time series of 21 objectively defined indices of daily temperature (12) and precipitation (9) extremes from representative weather stations in the Kobresia meadow region to analyse the spatial pattern and regional trend in climate extremes over the period of 1961–2008. A general tendency towards more warm extremes is found over the Kobresia meadow and is more noticeable at night, although the increase in the warmest daytime temperature is larger than that of the warmest night-time temperature. The meadow region is, however, not experiencing a uniform tendency in terms of precipitation extremes, except for a decrease in consecutive dry days, which seems to occur especially at higher altitudes. Regionally, there seems no obvious trend in rain intensity, but a quasi-decadal fluctuation occurs. The middle and eastern Kobresia meadow area has experienced relatively milder extreme climatic change especially in night-time cold temperatures and in precipitation. Targeted measures towards sustaining the Kobresia meadow need to take these regional differences in climatic extremes into account.