An integrated analysis of land-atmosphere interaction processes over landscapes of grassland, gravel and water in Lake Nam Co basin

Lake Nam Co is the third largest lake over the Tibetan Plateau and shows significant influences on the forming and the dvelopement of regional-scale weather and climate. In this study, an integrated analysis of land-atmosphere interaction processes (including meteorological variables, land-atmosphere water, heat and CO₂ flux exchange) is introduced based on in situ measurements of meteorological variables and eddy covariance fluxes over land surfaces of grassland, gravel and water surfaces. The meteorological variables measured at 20 m height of two planetary boundary layer towers in the island and over the grass land indicate that: (1) the air temperature is warmer in the island than that over the surrounding grass land during the open water season and air humidity in the island are all higher in the island than those at the surrounding grass land, with difference values of 0.6-0.7 g m^-3 during monsoon seasons (June to October) and 0.1-0.3 g m^-3 during other months. (2) the measured water, heat and CO₂ flux over the water and the grassland show significant differences, where the lake acts as a significant carbon sink during ice-forming periods and the monthly LE over the water surface are obviously higher than those at the grass land and gravel surface. Our results demonstrate that spatial heterogeneity of meteorologival variables and lake-atmosphere water, heat and CO₂ flux exist in Lake Nam Co basin, which may show hints for other lake catchment research worldwidely.