Vertical position changes of ground-based Global Navigation Satellite System(GNSS) stations have been used to study regional terrestrial water storage(TWS) changes. However, the feasibility is still unclear in many ar...Vertical position changes of ground-based Global Navigation Satellite System(GNSS) stations have been used to study regional terrestrial water storage(TWS) changes. However, the feasibility is still unclear in many areas due to diverse local effects. This study aims to evaluate the capability of GNSS vertical displacements in monitoring hydrological variations in four climate settings over Chinese mainland. The spatial and temporal variations of hydrological load-induced(HYDL) vertical displacements at 208 GNSS sites during 2011-2020 were analyzed by comparing with Gravity Recovery and Climate Experiment(GRACE)/GRACE Follow-On(GFO) and Global Land Data Assimilation System(GLDAS) derived TWS changes. The results indicate that GNSS vertical positions show different capabilities in capturing seasonal and non-seasonal hydrological dynamics in different climate regions. Among the four climatic settings, the subtropical monsoon climate(SMC) region, with the largest deformation fluctuation(the regional mean root mean square(RMS) is 7.97 mm), has the highest regional mean HYDL-GRACE and HYDL-GLDAS anti-correlation coefficients(CCs) of-0.47 and-0.45 at the seasonal scale, respectively. For the individual GNSS site, the number of the sites with CC <-0.40 between HYDL and GRACE/GLDASderived TWS changes accounts for 55.1% and 55.1%(SMC), 13.0% and 7.4%(temperate monsoon climate, TMC), 6.7% and 13.3%(temperate continental climate, TCC), 32.3% and 38.7%(plateau climate,PC), respectively. For the non-seasonal term, although the proportion with CC <-0.40 in each climate type decreases mainly due to the influence of local geodynamic and human activities, especially in the SMC and PC regions, GNSS site vertical deformations still show good capability in monitoring hydrological extremes. The results provide valuable information for better application of GNSS to hydrology.展开更多
In this study we compared weekly GNSS position time series with modelled values of crustal deformations on the basis of Gravity Recovery and Climate Experiment （GRACE） data. The Global Navigation Satellite Systems ...In this study we compared weekly GNSS position time series with modelled values of crustal deformations on the basis of Gravity Recovery and Climate Experiment （GRACE） data. The Global Navigation Satellite Systems （GNSS） time series were taken from homogeneously reprocessed global network solutions within the International GNSS Service （IGS） Reprucessing 1 project and from regional solutions performed by Warsaw University of Technology （WUT） European Permanent Network （EPN） Local Analysis Center （LAC） within the EPN reprocessing project. Eight GNSS sites from the territory of Poland with observation timespans between 2.5 and 13 years were selected for this study. The Total Water Equivalent （TWE） estimation from GRACE data was used to compute deformations using the Green＇s function formalism. High frequency components were removed from GRACE data to avoid aliasing problems. Since GRACE observes mainly the mass transport in continental storage of water, we also compared GRACE deformations and the GNSS position time series, with the deformations computed on the basis of a hydrosphere model. We used the output of Water GAP Hydrology Model （WGHM） to compute deformations in the same manner as for the GRACE data. The WGHM gave slightly larger amplitudes than GNSS and GRACE. The atmospheric non-tidal loading effect was removed from GNSS position time series before comparing them with modelled deformations. The results confirmed that the major part of observed seasonal variations for GNSS vertical components can be attributed to the hy- drosphere loading. The results for these components agree very well both in the amplitude and phase. The decrease in standard deviation of the residual GNSS position time series for vertical components corrected for the hydrosphere loading reached maximally 36% and occurred for all but one stations for both global and regional solutions. For horizontal components the amplitudes are about three times smaller than for vertical components therefore the comparison is much more complicated and the conclusions are ambiguous.展开更多
The concentration of runoff depends upon that of soil loss and the latter is assumed to be linear to the value of EI that equals the product of total storm energy E times the maximum 30-min intensity I 30 for a giv...The concentration of runoff depends upon that of soil loss and the latter is assumed to be linear to the value of EI that equals the product of total storm energy E times the maximum 30-min intensity I 30 for a given rainstorm. Usually, the maximum accumulative amount of rain for a rainstorm might bring on the maximum amount of runoff, but it does not equal the maximum erosion and not always lead the maximum concentration. Thus, the average concentration weighted by amount of runoff is somewhat unreasonable. An improvement for the calculation method of non-point source pollution load put forward by professor Li Huaien is proposed. In replacement of the weight of runoff, EI value of a single rainstorm is introduced as a new weight. An example of Fujing River watershed shows that its application is effective.展开更多
基金supported by National Natural Science Foundation of China(42064002,42004013,42204006)the GuangxiNatural Science Foundation of China(2024GXNSFDA010041)+5 种基金Guangdong Basic and Applied Basic Research Foundation(2022A1515010469)Guangxi Key Laboratory of Spatial Information and Geomatics(Grant no.21-238-21-05)the Open Fund of Hubei Luojia Laboratory(230100019,230100020)The GNSS observation data are provided by Crustal Movement Observation Network of China(CMONC)The GRACE/GFO mascon gravimetry data products are provided by NASA Jet Propulsion Laboratory/California Institute of TechnologyThe GLDAS data products are provided by NASA Earthdata.
文摘Vertical position changes of ground-based Global Navigation Satellite System(GNSS) stations have been used to study regional terrestrial water storage(TWS) changes. However, the feasibility is still unclear in many areas due to diverse local effects. This study aims to evaluate the capability of GNSS vertical displacements in monitoring hydrological variations in four climate settings over Chinese mainland. The spatial and temporal variations of hydrological load-induced(HYDL) vertical displacements at 208 GNSS sites during 2011-2020 were analyzed by comparing with Gravity Recovery and Climate Experiment(GRACE)/GRACE Follow-On(GFO) and Global Land Data Assimilation System(GLDAS) derived TWS changes. The results indicate that GNSS vertical positions show different capabilities in capturing seasonal and non-seasonal hydrological dynamics in different climate regions. Among the four climatic settings, the subtropical monsoon climate(SMC) region, with the largest deformation fluctuation(the regional mean root mean square(RMS) is 7.97 mm), has the highest regional mean HYDL-GRACE and HYDL-GLDAS anti-correlation coefficients(CCs) of-0.47 and-0.45 at the seasonal scale, respectively. For the individual GNSS site, the number of the sites with CC <-0.40 between HYDL and GRACE/GLDASderived TWS changes accounts for 55.1% and 55.1%(SMC), 13.0% and 7.4%(temperate monsoon climate, TMC), 6.7% and 13.3%(temperate continental climate, TCC), 32.3% and 38.7%(plateau climate,PC), respectively. For the non-seasonal term, although the proportion with CC <-0.40 in each climate type decreases mainly due to the influence of local geodynamic and human activities, especially in the SMC and PC regions, GNSS site vertical deformations still show good capability in monitoring hydrological extremes. The results provide valuable information for better application of GNSS to hydrology.
文摘In this study we compared weekly GNSS position time series with modelled values of crustal deformations on the basis of Gravity Recovery and Climate Experiment （GRACE） data. The Global Navigation Satellite Systems （GNSS） time series were taken from homogeneously reprocessed global network solutions within the International GNSS Service （IGS） Reprucessing 1 project and from regional solutions performed by Warsaw University of Technology （WUT） European Permanent Network （EPN） Local Analysis Center （LAC） within the EPN reprocessing project. Eight GNSS sites from the territory of Poland with observation timespans between 2.5 and 13 years were selected for this study. The Total Water Equivalent （TWE） estimation from GRACE data was used to compute deformations using the Green＇s function formalism. High frequency components were removed from GRACE data to avoid aliasing problems. Since GRACE observes mainly the mass transport in continental storage of water, we also compared GRACE deformations and the GNSS position time series, with the deformations computed on the basis of a hydrosphere model. We used the output of Water GAP Hydrology Model （WGHM） to compute deformations in the same manner as for the GRACE data. The WGHM gave slightly larger amplitudes than GNSS and GRACE. The atmospheric non-tidal loading effect was removed from GNSS position time series before comparing them with modelled deformations. The results confirmed that the major part of observed seasonal variations for GNSS vertical components can be attributed to the hy- drosphere loading. The results for these components agree very well both in the amplitude and phase. The decrease in standard deviation of the residual GNSS position time series for vertical components corrected for the hydrosphere loading reached maximally 36% and occurred for all but one stations for both global and regional solutions. For horizontal components the amplitudes are about three times smaller than for vertical components therefore the comparison is much more complicated and the conclusions are ambiguous.
基金FoundationofSichuanScienceandTech nologyCommittee (No .0 1SG4 7 0 2 )
文摘The concentration of runoff depends upon that of soil loss and the latter is assumed to be linear to the value of EI that equals the product of total storm energy E times the maximum 30-min intensity I 30 for a given rainstorm. Usually, the maximum accumulative amount of rain for a rainstorm might bring on the maximum amount of runoff, but it does not equal the maximum erosion and not always lead the maximum concentration. Thus, the average concentration weighted by amount of runoff is somewhat unreasonable. An improvement for the calculation method of non-point source pollution load put forward by professor Li Huaien is proposed. In replacement of the weight of runoff, EI value of a single rainstorm is introduced as a new weight. An example of Fujing River watershed shows that its application is effective.
