No Significant Shift of Warming Trend over the Last Two Decades on the Mid-South of Tibetan Plateau

摘要

Climate warming on the Tibetan Plateau has been regarded as an important driving force of regional environmental change. Although several studies have analyzed the shift of warming trends on this plateau within the context of a recent global warming “hiatus” since 1998, their disparate findings have hindered a comprehensive and regional understanding. Based on the daily mean temperature ( T mean ), maximum temperature ( T max ), and minimum temperature ( T min ) collected from meteorological stations on the period of 1961–2017, we re-examined the timing and magnitude of temperature phase change using piecewise linear regression on the mid-south of Tibetan Plateau. The results show that among the trends in regional annual T mean , T max and T min , the statistically significant change-point was observed only in annual T max ( p 0.01) . The warming trend of annual T max has accelerated significantly since 1992 and has exceeded that of annual T min after 2000, causing a remarkable reversal from decline to increase in diurnal temperature range (DTR) ( p 0.01). Spatially, the occurrence time of change-points in T mean , T max, and T min varied among stations, but most of them occurred before the mid-1990s. Besides, the trend shifts in T max /DTR during the cold season played a primary role in the significant trend shifts in annual T max /DTR. This study underscores that there is no significant shift of warming trends over the last two decades on the mid-south of Tibetan Plateau.