Climatic difference in dry and wet season under effect of the Longitudinal Range-Gorge and its influence on transboundary river runoff

Based on observed data of transboundary river runoffs in the Longitudinal Range-Gorge Region （LRGR） and those of precipitation and air temperature fields in Yunnan, climatic variability in dry and wet seasons under the impact of LRGR and its influence on transboundary river runoff are studied by means of statistical analysis and wavelet transforms. Results show that latitude variations of high correlation center for precipitation field and corresponding transboundary river runoff are not so notable due to the underlying topography of LRGR, while longitude variations are highly marked. In dry season, greater precipitation and slighter relative deviation are observed in the eastern part as compared to those in the western part of LRGR; while lower average temperature and greater standard deviation are found in the eastern part. In wet season, greater precipitation and slighter relative deviation are ob- served in the western part, while lower average temperature and similar standard deviation are found in the eastern part. Either in dry or wet season, relative deviation of eastern runoff is always greater than that of the western one. LRGR＇s barrier action is stronger for southwest monsoon but weaker for northeast one. Under the effect of LRGR, precipitation variations in the eastern and western parts are primarily found in smaller timescales, and the variations tend to be insignificant as timescales increase; whereas slighter temperature variations are observed In recent years, precipitation in wet season tended to increase, which in turn resulted in the greater runoff of transboundary rivers. While in the past decade, air temperature showed a climbing trend in both dry and wet season in the LRGR.

Climatic difference in dry and wet season under effect of the Longitudinal Range-Gorge and its influence on transboundary river runoff