Temperature and precipitation trends and their links with elevation in the Hengduan Mountain region, China

ABSTRACT: Annual, seasonal, and monthly changes in temperature and precipitation and their links with elevation in the Hengduan Mountain region (HDMR) in China were analyzed based on the daily climate data of 90 meteorological stations from 1961-2011. The results demonstrate that the average annual mean temperature in the HDMR exhibited significant increasing trends of 0.16°C decade-1 during 1961-2011. The warming trends were found to be more apparent in winter (December-January-February) and autumn (September-October-November) than in summer (June-July-August) and spring (March-April-May). All of the 12 monthly mean temperatures increased, with trends ranging from 0.01-0.24°C per 10 yr. Temperatures increased by 0.06°C per 10 yr per 1000 m for elevations ranging from 500-4000 m. The elevation dependency of climatic warming was most robust in winter followed by spring and summer, and was weakest in autumn. The magnitudes of the monthly temperature changes ranged from 0.02-0.10°C per 10 yr per 1000 m. The relationships between annual, seasonal, and monthly temperature trends and elevation indicate evidence of elevation-dependent warming. The average annual total precipitation showed a nonsignificant decreasing trend of -11.41 mm decade-1 in the HDMR from 1961-2011. Summer, autumn, and winter precipitation showed nonsignificant decreasing trends during 1961-2011, while spring precipitation exhibited an increasing trend at a rate of 7.34 mm decade-1. The HDMR exhibited a wetting trend during January to May and a drying trend during June to December. The annual and seasonal precipitation changes showed positive correlations with elevation, but annual and seasonal precipitation decreased, except for the spring precipitation (which increased significantly). The relationships between annual and seasonal precipitation trends and elevation indicate that the higher altitude regions experienced a slower drying trend than regions at a lower altitude. The spring precipitation increasing trend was amplified with elevation. This study will be helpful for improving our understanding of the variabilities in temperature and precipitation in response to climate change, and will provide support for water resource management in the HDMR.