[A-HW22] Advancements in quantification of natural and anthropogenic influences on terrestrial water cycle

[AHW22-P02] Assessment of decadal climatic trends, variability and hydro-meteorological characteristics of Lancang River Basin

*Yi Yu¹, Tsuyoshi Kinouchi¹ (1.Tokyo Institute of Technology)

The Lancang River Basin, as the source region of the Mekong River Basin connecting six countries, runoff changes in the Lancang River Basin are closely related to the water resources and economic and social development of each country. Therefore, it is necessary to deeply understand the temporal and spatial hydrological characteristics of the Lancang River Basin as well as how it is affected by climate change and human activities, thus providing reference for more rational water resource management. In this study, the decadal trends of hydro-climatic parameters were assessed based on Mann-Kendall method for the period between 1981 and 2020. The overall precipitation and runoff in the basin showed a decreasing trend and the temperature showed an increasing trend. the precipitation in the source area and downstream area showed an insignificant increase trend, while the precipitation in the middle area decreased, and significantly decreased in the dry season, which, together with warmer temperature, influenced changes in evapotranspiration and surface runoff distribution. M-K breakpoint analysis showed the sudden change in runoff associated with the construction of dams on the Lancang River. Furthermore, since this Lancang River Basin spans north-south with complex topography and in different provinces for management, SWAT model was applied to each of upper, middle, and lower of the basin, and quantitatively and more accurately assess the effects of climate change and human activities on the changes of runoff and its constituent components in the Lancang River Basin. In this way, appropriate water management strategies can be developed in coordination with different local characteristics.