By using remote sensing and GIS technologies, spatial analysis and statistic analysis, we calculated the water area and volume variations of the Nam Co Lake from 1971-2004, and discussed their influence factors from t...By using remote sensing and GIS technologies, spatial analysis and statistic analysis, we calculated the water area and volume variations of the Nam Co Lake from 1971-2004, and discussed their influence factors from the viewpoints of climatic change and water balance. Data source in this study includes bathymetric data of the lake, aerial surveyed topographic maps of 1970, remote sensing images of 1991 and 2004 in the lake catchment, meteorological data from 17 stations within 1971-2004 in the adjacent area of the lake catchment. The results showed that the lake area expanded from 1920 km2 to 2015 km2 during 1971 to 2004 with the mean annual increasing rate (MAIR) of 2.81 km2 a-1, and the lake volume augmented from 783.23×108 m3 to 863.77×108 m3 with the MAIR of 2.37×108 m3. Moreover, the MAIR of the lake area and volume are both higher during 1992 to 2004 (4.01 km2 a-1 and 3.61×108 m3 a-1) than those during 1971 to 1991 (2.06 km2 a-1 and 1.60×108 m3 a-1). Analyses of meteorological data indicated that the continue rising of air temperature conduced more glacier melting water. This part of water supply, together with the increasing precipitation and the descending evaporation, contributed to the enlargement of Nam Co Lake. The roughly water balance analyses of lake water volume implied that, in two study periods (1971-1991 and 1992-2004), the precipitation supplies (direct precipitations on the lake area and stream flow derived from precipitations) accounted for 63% and 61.92% of the whole supplies, while the glacier melting water supplies occupied only 8.55% and 11.48%, respectively. This showed that precipitations were main water supplies of the Nam Co Lake. However, for the reason of lake water increasing, the increased amount from precipitations accounted for 46.67% of total increased water supplies, while the increased amount from glacier melting water reached 52.86% of total increased water supplies. The ratio of lake evaporation and lake volume augment showed that 95.71% of total increased water suppl展开更多
基金supported by the National Basic Research Program of China (Grant No. 2005CB422002)National Natural Science Foundation of China (Grant No. 40871099)+1 种基金Innovation Project of Chinese Academy of Sciences (Grant No. KZCX2-YW-146)EU Sixth Frame-work Project (BRAHMATWINN, Grant No. FP6-036952)
文摘By using remote sensing and GIS technologies, spatial analysis and statistic analysis, we calculated the water area and volume variations of the Nam Co Lake from 1971-2004, and discussed their influence factors from the viewpoints of climatic change and water balance. Data source in this study includes bathymetric data of the lake, aerial surveyed topographic maps of 1970, remote sensing images of 1991 and 2004 in the lake catchment, meteorological data from 17 stations within 1971-2004 in the adjacent area of the lake catchment. The results showed that the lake area expanded from 1920 km2 to 2015 km2 during 1971 to 2004 with the mean annual increasing rate (MAIR) of 2.81 km2 a-1, and the lake volume augmented from 783.23×108 m3 to 863.77×108 m3 with the MAIR of 2.37×108 m3. Moreover, the MAIR of the lake area and volume are both higher during 1992 to 2004 (4.01 km2 a-1 and 3.61×108 m3 a-1) than those during 1971 to 1991 (2.06 km2 a-1 and 1.60×108 m3 a-1). Analyses of meteorological data indicated that the continue rising of air temperature conduced more glacier melting water. This part of water supply, together with the increasing precipitation and the descending evaporation, contributed to the enlargement of Nam Co Lake. The roughly water balance analyses of lake water volume implied that, in two study periods (1971-1991 and 1992-2004), the precipitation supplies (direct precipitations on the lake area and stream flow derived from precipitations) accounted for 63% and 61.92% of the whole supplies, while the glacier melting water supplies occupied only 8.55% and 11.48%, respectively. This showed that precipitations were main water supplies of the Nam Co Lake. However, for the reason of lake water increasing, the increased amount from precipitations accounted for 46.67% of total increased water supplies, while the increased amount from glacier melting water reached 52.86% of total increased water supplies. The ratio of lake evaporation and lake volume augment showed that 95.71% of total increased water suppl
