According to the analysis of the climate materials including the topographic map in 1975, the TM and CBERS satellite remote sensing materials from the 1980s to 2005 as well as the air temperature, precipitation, evapo...According to the analysis of the climate materials including the topographic map in 1975, the TM and CBERS satellite remote sensing materials from the 1980s to 2005 as well as the air temperature, precipitation, evaporation rate, maximum depth of snow and the biggest depth of frozen soil in the past 45 years, the water level area of four lakes at the southeast of Nagqu, Tibet including Barn Co, Pung Co, Dung Co and Nuripung Co show a distinct trend of expansion in the past 30 years. In 2005, the water level area of the above four lakes increased by 48.2 km^2, 38.2 km^2, 19.8 km^2 and 26.0 km^2 respectively compared to 1975, with the respective increase rate of 25.6%, 28.2%, 16.2% and 37.6%. That is closely related to the warming and humidified climate change in the recent years such as rise of the air temperature increase of the precipitation, decrease of the evaporation rate and permafrost degradation.展开更多
Lakes in the Tibetan Plateau are considered sensitive responders to global warming Variations in physical features of lake systems such as surface area and water level are very helpful in understanding regional respon...Lakes in the Tibetan Plateau are considered sensitive responders to global warming Variations in physical features of lake systems such as surface area and water level are very helpful in understanding regional responses to global warming in recent decades. In this study multi-source remote sensing data were used to retrieve the surface area and water level time series of five inland lakes in the south-central part of the Tibetan Plateau over the past dec- ades. Changes in water level and surface area of the lakes were investigated. The results showed that the water level of three lakes （Puma Yumco, Taro Co, Zhari Namco） increased, with expanding surface area, while the water levels of the other two lakes （Paiku Co, Mapam Yumco） fell, with shrinking area. The water levels of the lakes experienced remarkable changes in 2000-2012 as compared with 1976-1999. Spatially, lakes located at the southern fringe of the Tibetan Plateau showed consistency in water level changes, which was different from lakes in the central Tibetan Plateau.展开更多
Lakes are important ecological water sources in the Bashang Plateau. Its expansion or shrinkage directly affects the ecological security of the plateau and its surrounding areas. In this study, Landsat images from 198...Lakes are important ecological water sources in the Bashang Plateau. Its expansion or shrinkage directly affects the ecological security of the plateau and its surrounding areas. In this study, Landsat images from 1984 to 2015 were selected to monitor the area of lakes in the Bashang Plateau and to analyze the spatiotemporal evolution and driving forces of lakes in the Bashang Plateau. The results showed that there were 47 lakes in the Bashang Plateau in 2015, with a total area of 37.63 km2, mainly distributed in the central and western regions of the region. From 1984 to 2015, the lakes in Bashang Plateau showed a shrinking trend. At the same time, there are obvious stage differences in lake changes. During 1984-1996, the number of lakes increased by 99 and the total area increased by 124.43 km2. From 1996 to 2015, the number of lakes decreased by 142, and the total area decreased by 183.96 km2. Before 1996, climate change was the dominant factor. However, the shrinkage of lakes after 1996 is the result of climate change and human activities. Among them, the large-scale planting of water consuming crops such as vegetables is the main human activity mode leading to lake shrinkage. This study will help to understand the expansion and contraction factors of the Bashang Plateau lakes in Hebei province and provide a reference for the future protection and management of the lakes.展开更多
目的了解2015年青海省某高原盐湖企业高纯优质碳酸锂生产装置职业病危害因素分布情况,提出可行性防护对策,为同类企业职业病防治提供依据。方法依据《工业企业设计卫生标准》等职业卫生标准和规范,采用职业卫生现场调查等方法对该生产...目的了解2015年青海省某高原盐湖企业高纯优质碳酸锂生产装置职业病危害因素分布情况,提出可行性防护对策,为同类企业职业病防治提供依据。方法依据《工业企业设计卫生标准》等职业卫生标准和规范,采用职业卫生现场调查等方法对该生产工艺进行调查与评价。结果工作场所空气中粉尘和毒物时间加权平均浓度(TWA)符合职业接触限值;2个检测点碳酸锂粉尘和矽尘超限倍数超标,合格率为71.4%;各岗位工种接触噪声40 h等效声级均小于85 d B(A)。结论该企业职业病危害因素主要为碳酸锂粉尘和矽尘,需加强防护设施及酸碱输送管道的维护检修,避免跑、冒、滴、漏现象发生,确保防护有效。展开更多
基金National Natural Science Foundation of China, No.40761005
文摘According to the analysis of the climate materials including the topographic map in 1975, the TM and CBERS satellite remote sensing materials from the 1980s to 2005 as well as the air temperature, precipitation, evaporation rate, maximum depth of snow and the biggest depth of frozen soil in the past 45 years, the water level area of four lakes at the southeast of Nagqu, Tibet including Barn Co, Pung Co, Dung Co and Nuripung Co show a distinct trend of expansion in the past 30 years. In 2005, the water level area of the above four lakes increased by 48.2 km^2, 38.2 km^2, 19.8 km^2 and 26.0 km^2 respectively compared to 1975, with the respective increase rate of 25.6%, 28.2%, 16.2% and 37.6%. That is closely related to the warming and humidified climate change in the recent years such as rise of the air temperature increase of the precipitation, decrease of the evaporation rate and permafrost degradation.
基金We thank the Climate Data Center, National Meteorological Information Center, China Me- teorological Administration, for providing the long-time meteorological data of the four field stations. This research was jointly supported by The ＂Strategic Priority Research Program （B）＂ of the Chinese Academy of Sciences （Grant XDB03030406）, and the National Natural Science Foundation of China （Grant 41371218, 41165011）.
文摘Lakes in the Tibetan Plateau are considered sensitive responders to global warming Variations in physical features of lake systems such as surface area and water level are very helpful in understanding regional responses to global warming in recent decades. In this study multi-source remote sensing data were used to retrieve the surface area and water level time series of five inland lakes in the south-central part of the Tibetan Plateau over the past dec- ades. Changes in water level and surface area of the lakes were investigated. The results showed that the water level of three lakes （Puma Yumco, Taro Co, Zhari Namco） increased, with expanding surface area, while the water levels of the other two lakes （Paiku Co, Mapam Yumco） fell, with shrinking area. The water levels of the lakes experienced remarkable changes in 2000-2012 as compared with 1976-1999. Spatially, lakes located at the southern fringe of the Tibetan Plateau showed consistency in water level changes, which was different from lakes in the central Tibetan Plateau.
文摘Lakes are important ecological water sources in the Bashang Plateau. Its expansion or shrinkage directly affects the ecological security of the plateau and its surrounding areas. In this study, Landsat images from 1984 to 2015 were selected to monitor the area of lakes in the Bashang Plateau and to analyze the spatiotemporal evolution and driving forces of lakes in the Bashang Plateau. The results showed that there were 47 lakes in the Bashang Plateau in 2015, with a total area of 37.63 km2, mainly distributed in the central and western regions of the region. From 1984 to 2015, the lakes in Bashang Plateau showed a shrinking trend. At the same time, there are obvious stage differences in lake changes. During 1984-1996, the number of lakes increased by 99 and the total area increased by 124.43 km2. From 1996 to 2015, the number of lakes decreased by 142, and the total area decreased by 183.96 km2. Before 1996, climate change was the dominant factor. However, the shrinkage of lakes after 1996 is the result of climate change and human activities. Among them, the large-scale planting of water consuming crops such as vegetables is the main human activity mode leading to lake shrinkage. This study will help to understand the expansion and contraction factors of the Bashang Plateau lakes in Hebei province and provide a reference for the future protection and management of the lakes.
文摘目的了解2015年青海省某高原盐湖企业高纯优质碳酸锂生产装置职业病危害因素分布情况,提出可行性防护对策,为同类企业职业病防治提供依据。方法依据《工业企业设计卫生标准》等职业卫生标准和规范,采用职业卫生现场调查等方法对该生产工艺进行调查与评价。结果工作场所空气中粉尘和毒物时间加权平均浓度(TWA)符合职业接触限值;2个检测点碳酸锂粉尘和矽尘超限倍数超标,合格率为71.4%;各岗位工种接触噪声40 h等效声级均小于85 d B(A)。结论该企业职业病危害因素主要为碳酸锂粉尘和矽尘,需加强防护设施及酸碱输送管道的维护检修,避免跑、冒、滴、漏现象发生,确保防护有效。
