Spatiotemporal change of diurnal temperature range and its relationship with sunshine duration and precipitation in China

摘要

We examined the spatiotemporal variation in diurnal temperature range (DTR) and discussed the reasons for the changes of DTR in China based on data from 479 weather stations from 1962 to 2011. Results showed that DTR decreased rapidly (0.291°C/decade) from 1962 to 1989 due to slightly decreased T_(max) and significantly increased T_(min), but the decrease in DTR has stopped since 1990 as T_(max) and T_(min) kept pace with each other. During 1990–2011, DTR remained trendless, with slight increase in the 1990s and slight decrease after 2000. During the whole study period from 1962 to 2011, DTR decreased at a rate of 0.157°C/decade nationally. Spatially, decreases in DTR were greatest in Northeast China and lowest in Southwest China with a transect running from northeast to southwest showing the decreasing trends change from high to low. Seasonally, DTR decreases were greatest in winter and lowest in summer, and the magnitudes of decrease reduced from the north to south of China. The changes in DTR were closely correlated with changes in sunshine duration (SD) in China except the Tibetan Plateau, suggesting that SD decrease is an important contributor to the decrease of DTR through its influence on T_(max). In addition to the contribution of SD decrease, the increasing of precipitation played an important role in DTR decrease in Northwest China, the most arid region of China. It appeared that changes of cloud cover (CC) were not the reasons for DTR changes in the past 50 years as CC has decreased during the study period.