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Water storage changes in North America retrieved from GRACE gravity and GPS data 被引量:2
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作者 Wang Hansheng Xiang Longwei +4 位作者 Jia Lulu Wu Patrick Steffen Holger Jiang Liming Shen Qiang 《Geodesy and Geodynamics》 2015年第4期267-273,共7页
As global warming continues,the monitoring of changes in terrestrial water storage becomes increasingly important since it plays a critical role in understanding global change and water resource management.In North Am... As global warming continues,the monitoring of changes in terrestrial water storage becomes increasingly important since it plays a critical role in understanding global change and water resource management.In North America as elsewhere in the world,changes in water resources strongly impact agriculture and animal husbandry.From a combination of Gravity Recovery and Climate Experiment(GRACE) gravity and Global Positioning System(GPS) data,it is recently found that water storage from August,2002 to March,2011 recovered after the extreme Canadian Prairies drought between 1999 and 2005.In this paper,we use GRACE monthly gravity data of Release 5 to track the water storage change from August,2002 to June,2014.In Canadian Prairies and the Great Lakes areas,the total water storage is found to have increased during the last decade by a rate of 73.8 ± 14.5 Gt/a,which is larger than that found in the previous study due to the longer time span of GRACE observations used and the reduction of the leakage error.We also find a long term decrease of water storage at a rate of-12.0 ± 4.2 Gt/a in Ungava Peninsula,possibly due to permafrost degradation and less snow accumulation during the winter in the region.In addition,the effect of total mass gain in the surveyed area,on present-day sea level,amounts to-0.18 mm/a,and thus should be taken into account in studies of global sea level change. 展开更多
关键词 Canadian Prairies Great Lakes Ungava Peninsula water storage changes gravity Recovery and Climate Experiment (GRACE) data Global Positioning System (GPS) data Glacial isostatic adjustment Separation approach
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Stream Function Wave Derived by Unified Variational Principle of Water Gravity Wave
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作者 Fu Yuhua Senior Engineer, China Offshore Oil Production Research Center, P.O.Box 9607, Beijing, 100086 《China Ocean Engineering》 SCIE EI 1997年第2期187-200,共14页
Based on the linear wave, solitary wave and fifth order stokes wave derived by use of the Unified Variational Principle of Water Gravity Wave (UVPWGW), this paper derives stream function wave theory by using UVPWGW. T... Based on the linear wave, solitary wave and fifth order stokes wave derived by use of the Unified Variational Principle of Water Gravity Wave (UVPWGW), this paper derives stream function wave theory by using UVPWGW. This paper will handle the Kinematic Free Surface Boundary Condition (KFSBC) and Dynamic Free Surface Boundary Condition (DFSBC) directly and give the optimum solution, instead of the conditions Sigma(Q(av) - Q(i))(2) = min, and the related equations of stational condition. When the wave height H, period T and water depth D are given, the original stream function wave will be determined, and can not be adjusted if it does not agree with the real case; in the present method, the adjustment can be done by adding several constraint conditions, for example, the wave profile can be adjusted according to the condition of accurate peak position. The examples given in this paper show that for the original stream function wave, the DFSBC can be fairly well satisfied, but the KFSBC can not; however, the stream function wave derived by UVPWGW is better than the original one in the sense of minimum error squares in the aspect of the level at which KFSBC and DFSBC are satisfied. 展开更多
关键词 unified variational principle of water gravity wave stream function wave theory optimum solution
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Proof of Six-Wave Resonance Conditions of Ocean Surface Gravity Waves in Deep Water
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作者 LIN Guo-bin HUANG Hu 《China Ocean Engineering》 SCIE EI CSCD 2019年第6期734-738,共5页
A necessary big step up in the modern water wave theories and their widespread application in ocean engineering is how to obtain 6-wave resonance conditions and to prove it. In the light of the existing forms and char... A necessary big step up in the modern water wave theories and their widespread application in ocean engineering is how to obtain 6-wave resonance conditions and to prove it. In the light of the existing forms and characteristics of 3-wave, 4-wave and 5-wave resonance conditions, the 6-wave resonance conditions are proposed and proved for currently a maximum wave-wave resonance interactions of the ocean surface gravity waves in deep water, which will be indispensable to both the Kolmogorov spectrum of the corresponding universal wave turbulence and a synthetic 4-5-6-wave resonant model for the ocean surface gravity waves. 展开更多
关键词 6-wave resonance conditions PROOF ocean surface gravity waves in deep water wave turbulence
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Effects of Seasonal Variations in Physical Parameters on Quality of Gravity Flow Water in Kyanamira Sub-County, Kabale District, Uganda
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作者 Hannington Ngabirano Denis Byamugisha Emmanuel Ntambi 《Journal of Water Resource and Protection》 2016年第13期1297-1309,共13页
The effect of seasonal variations in physical parameters on quality of gravity flow water was investigated in Kyanamira Sub-County, Kabale District, Uganda. The seasonal variations in the physical parameters (pH, temp... The effect of seasonal variations in physical parameters on quality of gravity flow water was investigated in Kyanamira Sub-County, Kabale District, Uganda. The seasonal variations in the physical parameters (pH, temperature, electrical conductivity (EC), turbidity, colour, total dissolved solids (TDS), and total suspended solids (TSS)) were determined during wet and dry seasons. Composite samples from gravity flow water sources were collected monthly from March to August, 2014 and then analyzed. Temperature was measured using thermometer;pH, EC and TDS were determined using a multimeter, turbidity, colour and total suspended solids were determined by spectrophotometric method. TDS, pH and temperature were the most contributing parameters to water quality variations in both seasons. The mean pH values varied between 3.78 - 4.84 from March to August, 2014 at all study sites. These pH values were consistently below the WHO permissible range of 6.5 - 8.5. Similarly, total suspended solids varied between 0.66 - 2.17 mg·L<sup>-1</sup> and were well above the recommended WHO limit of zero mg·L<sup>-1</sup> at all study sites. Turbidity mean values varied between 0.83 - 3.7 NTU and were outside the recommended limits of 3 NTU at Kigata (3.7 NTU) only. Temperatures (20.3°C - 21.15°C) for all the study sites were within the recommended limit of 20°C - 30°C in water for domestic purposes. The mean values of physical parameters for the wet season were: temperature (21.12°C), colour (12.5 PtCoU), turbidity (3.4 NTU), TDS (76.76 mg·L<sup>-1</sup>), TSS (2.13 mg·L<sup>-1</sup>), pH (4.19) and EC (152.7 μS·cm<sup>-1</sup>) were different from those of the dry season (temperature (20.99&#176C), colour (0.93 PtCoU), turbidity (0.53 NTU), TDS (77.33 mg·L<sup>-1</sup>), TSS (0.67 mg·L<sup>-1</sup>), pH (4.86) and EC (158.65 μS·cm<sup>-1</sup>). Basing on these findings above, it was evident to justify discouraging the use of gravity flow water at these study sites for domestic purposes without proper treatment. 展开更多
关键词 Kyanamira Sub-County Seasonal Variations gravity Flow water Physical Parameters
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Effectiveness of empirical orthogonal function used in decorrelation of GRACE time-variable gravity field 被引量:2
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作者 Zhao Qian Wu Yunlong Wu Weiwei 《Geodesy and Geodynamics》 2015年第5期324-332,共9页
Empirical orthogonal function (EOF) was used to process the spherical harmonic coefficient (SHC) of 115 Gravity Recovery and Climate Experiment (GRACE) RL05 monthly gravity field models from March 2003 to Februa... Empirical orthogonal function (EOF) was used to process the spherical harmonic coefficient (SHC) of 115 Gravity Recovery and Climate Experiment (GRACE) RL05 monthly gravity field models from March 2003 to February 2013 released by CSR (Center for Space Research). We analyzed the effectiveness of EOF in decorrelation of gravity field. Results show that only a small Gaussian smoothing radius was needed by EOF to significantly weaken the north -south stripes compared with the empirical moving-window filtering algorithm. The comparative experiments with a Global Land Data Assimilation System (GLDAS) hydrological model also show that EOF did not much affect the real geophysical signals, and that the removed signals were nearly uncorrelated with the real geophysical signals. As the Gravity Recovery and Climate Experiment (GRACE) missions continue, EOF can be used to significantly remove the correlated errors from monthly gravity fields and reserve rich effective signals. 展开更多
关键词 Empirical orthogonal functiongravity recovery and climateexperiment (GRACE) gravity fieldDeeorrelationTerrestrial water storageGlobal Land Data AssimilationSystem (GLDAS)
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WHU-Grace01s:A new temporal gravity field model recovered from GRACE KBRR data alone 被引量:2
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作者 Zhou Hao Luo Zhicai Zhong Bo 《Geodesy and Geodynamics》 2015年第5期316-323,共8页
A new temporal gravity field model called WHU-Grace01s solely recovered from Gravity Recovery and Climate Experiment (GRACE) K-Band Range Rate (KBRR) data based on dynamic integral approach is presented in this pa... A new temporal gravity field model called WHU-Grace01s solely recovered from Gravity Recovery and Climate Experiment (GRACE) K-Band Range Rate (KBRR) data based on dynamic integral approach is presented in this paper. After meticulously preprocessing of the GRACE KBRR data, the root mean square of its post residuals is about 0.2 micrometers per second, and seventy-two monthly temporal solutions truncated to degree and order 60 are computed for the period from January 2003 to December 2008. After applying the combi- nation filter in WHU-Grace01s, the global temporal signals show obvious periodical change rules in the large-scale fiver basins. In terms of the degree variance, our solution is smaller at high degrees, and shows a good consistency at the rest of degrees with the Release 05 models from Center for Space Research (CSR), GeoForschungsZentrum Potsdam (GFZ) and Jet Pro- pulsion Laboratory 0PL). Compared with other published models in terms of equivalent water height distribution, our solution is consistent with those published by CSR, GFZ, JPL, Delft institute of Earth Observation and Space system (DEOS), Tongji University (Tongji), Institute of Theoretical Geodesy (ITG), Astronomical Institute in University of Bern (AIUB) and Groupe de Recherche de Geodesie Spatiale (GRGS}, which indicates that the accuracy of WHU-Grace01s has a good consistency with the previously published GRACE solutions. 展开更多
关键词 Temporal gravity field model gravity Recovery and Climate Experiment (GRACE) Dynamic integral approach K-Band Range Rate (KBRR) Satellite gravity Spherical harmonics Equivalent water height Geopotential determination
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Water storage variations in the Poyang Lake Basin estimated from GRACE and satellite altimetry 被引量:4
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作者 Yang Zhou Shuanggen Jin +1 位作者 Robert Tenzer Jialiang Feng 《Geodesy and Geodynamics》 2016年第2期108-116,共9页
The Gravity Recovery and Climate Experiment(GRACE) satellite mission provides a unique opportunity to quantitatively study terrestrial water storage(TWS) variations. In this paper,the terrestrial water storage var... The Gravity Recovery and Climate Experiment(GRACE) satellite mission provides a unique opportunity to quantitatively study terrestrial water storage(TWS) variations. In this paper,the terrestrial water storage variations in the Poyang Lake Basin are recovered from the GRACE gravity data from January 2003 to March 2014 and compared with the Global Land Data Assimilation System(GLDAS) hydrological models and satellite altimetry. Furthermore, the impact of soil moisture content from GLDAS and rainfall from the Tropical Rainfall Measuring Mission(TRMM) on TWS variations are investigated. Our results indicate that the TWS variations from GRACE, GLDAS and satellite altimetry have a general consistency. The TWS trends in the Poyang Lake Basin determined from GRACE, GLDAS and satellite altimetry are increasing at 0.0141 km^3/a, 0.0328 km^3/a and 0.0238 km^3/a,respectively during the investigated time period. The TWS is governed mainly by the soil moisture content and dominated primarily by the precipitation but also modulated by the flood season of the Yangtze River as well as the lake and river exchange water. 展开更多
关键词 gravity Recovery and Climate Experiment(GRACE) Satellite altimetry Terrestrial water storage variations Poyang Lake Basin
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Monthly gravity field recovery from GRACE orbits and K-band measurements using variational equations approach 被引量:1
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作者 Wang Changqing Xu Houze +1 位作者 Zhong Min Feng Wei 《Geodesy and Geodynamics》 2015年第4期253-260,共8页
The Gravity Recovery and Climate Experiment(GRACE) mission can significantly improve our knowledge of the temporal variability of the Earth's gravity field.We obtained monthly gravity field solutions based on varia... The Gravity Recovery and Climate Experiment(GRACE) mission can significantly improve our knowledge of the temporal variability of the Earth's gravity field.We obtained monthly gravity field solutions based on variational equations approach from GPS-derived positions of GRACE satellites and K-band range-rate measurements.The impact of different fixed data weighting ratios in temporal gravity field recovery while combining the two types of data was investigated for the purpose of deriving the best combined solution.The monthly gravity field solution obtained through above procedures was named as the Institute of Geodesy and Geophysics(IGG) temporal gravity field models.IGG temporal gravity field models were compared with GRACE Release05(RL05) products in following aspects:(i) the trend of the mass anomaly in China and its nearby regions within 2005-2010; (ii) the root mean squares of the global mass anomaly during 2005-2010; (iii) time-series changes in the mean water storage in the region of the Amazon Basin and the Sahara Desert between 2005 and 2010.The results showed that IGG solutions were almost consistent with GRACE RL05 products in above aspects(i)-(iii).Changes in the annual amplitude of mean water storage in the Amazon Basin were 14.7 ± 1.2 cm for IGG,17.1 ± 1.3 cm for the Centre for Space Research(CSR),16.4 ± 0.9 cm for the GeoForschungsZentrum(GFZ) and 16.9 ± 1.2 cm for the Jet Propulsion Laboratory(JPL) in terms of equivalent water height(EWH),respectively.The root mean squares of the mean mass anomaly in Sahara were 1.2 cm,0.9 cm,0.9 cm and 1.2 cm for temporal gravity field models of IGG,CSR,GFZ and JPL,respectively.Comparison suggested that IGG temporal gravity field solutions were at the same accuracy level with the latest temporal gravity field solutions published by CSR,GFZ and JPL. 展开更多
关键词 gravity recovery and climate experiment (GRACE) Temporal gravity field Variational equations approach water storage changes Equivalent water height(EWH)Data weight ratio Geoid height per degree IGG temporal gravity model
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Low-frequency variability of terrestrial water budget in China using GRACE satellite measurements from 2003 to 2010 被引量:1
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作者 Kang Kaixuan Li Hui +1 位作者 Peng Peng Zou Zhengbo 《Geodesy and Geodynamics》 2015年第6期444-452,共9页
Mass variations in terrestrial water storage(TWS) obtained from eight years of satellite data from the Gravity Recovery and Climate Experiment(GRACE) are used to describe low frequency TWS through Empirical Orthog... Mass variations in terrestrial water storage(TWS) obtained from eight years of satellite data from the Gravity Recovery and Climate Experiment(GRACE) are used to describe low frequency TWS through Empirical Orthogonal Function(EOF) analysis. Results of the second seasonal EOF mode show the influence of the Meiyu season. Annual variability is clearly shown in the precipitation distribution over China, and two new patterns of interannual variability are presented for the first time from observations, where two periods of abrupt acceleration are seen in 2004 and 2008. GRACE successfully measures drought events in southern China, and in this respect, an association with the Arctic Oscillation and El Nino-Southern Oscillation is discussed. This study demonstrates the unique potential of satellite gravity measurements in monitoring TWS variations and large-scale severe drought in China. 展开更多
关键词 gravity recovery and climate experiment(GRACE) Terrestrial water storage Drought event Global hydrology models water vapor transport Drought event Empirical orthogonal function(EOF) El Nino-southern oscillation(ENSO)
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