The Yalu Tsangpo River basin is a typical semi-arid and cold region in the Qinghai-Tibet Plateau, where significant climate change has been detected in the past decades. The objective of this paper is to demonstrate h...The Yalu Tsangpo River basin is a typical semi-arid and cold region in the Qinghai-Tibet Plateau, where significant climate change has been detected in the past decades. The objective of this paper is to demonstrate how the regional vegetation, especially the typical plant types, responds to the climate changes. In this study, the model of gravity center has been firstly introduced to analyze the spatial-temporal relationship between NDVI and climate factors considering the time-lag effect. The results show that the vegetation grown has been positively influenced by the rainfall and precipitation both in moving tracks of gravity center and time-lag effect especially for the growing season during the past thirteen years. The herbs and shrubs are inclined to be influenced by the change of rainfall and temperature, which is indicated by larger positive correlation coefficients at the 0.05 confidence level and shorter lagging time. For the soil moisture, the significantly negative relationship of NDV-PDI indicates that the growth and productivity of the vegetation are closely related to the short-term soil water, with the correlation coefficients reaching the maximum value of o.81 at Lag 0-1. Among the typicalvegetation types of plateau, the shrubs of low mountain, steppe and meadow are more sensitive to the change of soil moisture with coefficients of -0.95, -0.93, -0.92, respectively. These findings reveal that the spatial and temporal heterogeneity between NDVI and climatic factors are of great ecological significance and practical value for the protection of eco-environment in Qinghai-Tibet Plateau.展开更多
The water level in a deep well instantly responds to the earth’s tide and atmospheric pressure, and varies accordingly, not only in terms of amplitude but also in the phase lag. Therefore, phase lag correction is use...The water level in a deep well instantly responds to the earth’s tide and atmospheric pressure, and varies accordingly, not only in terms of amplitude but also in the phase lag. Therefore, phase lag correction is used in analyzing digital groundwater observation data in eastern China. Calculation results presented by the authors in this paper show that the correction method is effective in the identification of anomalous changes for short-term seismic precursors. The correction method can also be applied to the processing of observed deformation and tilt data.展开更多
基金funded by the National Natural Science Foundation of China (Grant No. 41201441, No. 41371363, and No. 41301501)Guangxi Key Laboratory of Spatial Information and Geomatics (Grant No. 1207115-18)the knowledge innovation project of the Chinese academy of sciences (Grant Nos. KZCX2YW-333, KZCXZ-EW-317)
文摘The Yalu Tsangpo River basin is a typical semi-arid and cold region in the Qinghai-Tibet Plateau, where significant climate change has been detected in the past decades. The objective of this paper is to demonstrate how the regional vegetation, especially the typical plant types, responds to the climate changes. In this study, the model of gravity center has been firstly introduced to analyze the spatial-temporal relationship between NDVI and climate factors considering the time-lag effect. The results show that the vegetation grown has been positively influenced by the rainfall and precipitation both in moving tracks of gravity center and time-lag effect especially for the growing season during the past thirteen years. The herbs and shrubs are inclined to be influenced by the change of rainfall and temperature, which is indicated by larger positive correlation coefficients at the 0.05 confidence level and shorter lagging time. For the soil moisture, the significantly negative relationship of NDV-PDI indicates that the growth and productivity of the vegetation are closely related to the short-term soil water, with the correlation coefficients reaching the maximum value of o.81 at Lag 0-1. Among the typicalvegetation types of plateau, the shrubs of low mountain, steppe and meadow are more sensitive to the change of soil moisture with coefficients of -0.95, -0.93, -0.92, respectively. These findings reveal that the spatial and temporal heterogeneity between NDVI and climatic factors are of great ecological significance and practical value for the protection of eco-environment in Qinghai-Tibet Plateau.
基金This project was sponsored by the Science and Technology Development Program(031060107) ,Shandong Province .
文摘The water level in a deep well instantly responds to the earth’s tide and atmospheric pressure, and varies accordingly, not only in terms of amplitude but also in the phase lag. Therefore, phase lag correction is used in analyzing digital groundwater observation data in eastern China. Calculation results presented by the authors in this paper show that the correction method is effective in the identification of anomalous changes for short-term seismic precursors. The correction method can also be applied to the processing of observed deformation and tilt data.
