IN 2004, archeologists discovered six tombs 10 meters underground in the walls of a loess ditch, 50-m-wide by 40-m-deep, north of Liangdai Village in Shaanxi’s Hancheng, 300 meters west of the Yellow River. Two
Although research on a field investigation about quantification drawdown of ground water wells has hitherto been conducted with emphasis on Sana'a basin which is 3 200 km2 in area characterized by general hazard i...Although research on a field investigation about quantification drawdown of ground water wells has hitherto been conducted with emphasis on Sana'a basin which is 3 200 km2 in area characterized by general hazard in quantity and quality of water,there exist uncertainties about the size of the hazardous annual decline in the level of underground water. So the authors are trying to assess reliable hazard data on the depth of ground-water which were obtained by measuring static water level. The data set are twenty six wells from 9 regions which were selected to represent Sana'a basin and collected during the course of the 20 months groundwater monitoring survey from January 2008 to January 2009. The results show that the average drawdown during 20 months to be 3.22 m with an average 0.16 m per month and 2 m per year.展开更多
Based on 11004 satellite images from CBERS CCD and Landsat TM/ETM,changes in the spatial characteristics of all lakes in China were determined following pre-established interpretation rules.This dataset was supported ...Based on 11004 satellite images from CBERS CCD and Landsat TM/ETM,changes in the spatial characteristics of all lakes in China were determined following pre-established interpretation rules.This dataset was supported by 6843 digital raster images(1:100000 and 1:50000),a countrywide digital vector dataset(1:250000),and historical literature.Comparative data were corrected for seasonal variations using precipitation data.There are presently 2693 natural lakes in China with an area greater than 1.0 km2,excluding reservoirs.These lakes are distributed in 28 provinces,autonomous regions and municipalities and have a total area of 81414.6 km2,accounting for-0.9% of China's total land area.In the past 30 years,the number of newly formed and newly discovered lakes with an area greater than 1.0 km2 is 60 and 131,respectively.Conversely,243 lakes have disappeared in this time period.展开更多
文摘IN 2004, archeologists discovered six tombs 10 meters underground in the walls of a loess ditch, 50-m-wide by 40-m-deep, north of Liangdai Village in Shaanxi’s Hancheng, 300 meters west of the Yellow River. Two
文摘Although research on a field investigation about quantification drawdown of ground water wells has hitherto been conducted with emphasis on Sana'a basin which is 3 200 km2 in area characterized by general hazard in quantity and quality of water,there exist uncertainties about the size of the hazardous annual decline in the level of underground water. So the authors are trying to assess reliable hazard data on the depth of ground-water which were obtained by measuring static water level. The data set are twenty six wells from 9 regions which were selected to represent Sana'a basin and collected during the course of the 20 months groundwater monitoring survey from January 2008 to January 2009. The results show that the average drawdown during 20 months to be 3.22 m with an average 0.16 m per month and 2 m per year.
基金supported by the National Special Basic Research Project (Gran No. 2006FY110600)
文摘Based on 11004 satellite images from CBERS CCD and Landsat TM/ETM,changes in the spatial characteristics of all lakes in China were determined following pre-established interpretation rules.This dataset was supported by 6843 digital raster images(1:100000 and 1:50000),a countrywide digital vector dataset(1:250000),and historical literature.Comparative data were corrected for seasonal variations using precipitation data.There are presently 2693 natural lakes in China with an area greater than 1.0 km2,excluding reservoirs.These lakes are distributed in 28 provinces,autonomous regions and municipalities and have a total area of 81414.6 km2,accounting for-0.9% of China's total land area.In the past 30 years,the number of newly formed and newly discovered lakes with an area greater than 1.0 km2 is 60 and 131,respectively.Conversely,243 lakes have disappeared in this time period.
