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
It is important to quantify mass variations in the Antarctic ice sheet hybrid filtering scheme employing a combination of the decorrelated to study the global sea-level rise and climate change. A filter P3M6 and 300 k...It is important to quantify mass variations in the Antarctic ice sheet hybrid filtering scheme employing a combination of the decorrelated to study the global sea-level rise and climate change. A filter P3M6 and 300 km Fan filter was used, and the sur- face mass variations over the Antarctic are recovered from GRACE CSR RL04 monthly gravity field models from August 2002 to June 2010. After deduction of leakage errors using the GLDAS hydrological model and postglacial rebound effects using the glacial isostatic adjustment model IJ05, the variations in the ice sheet mass are obtained. The results reveal that the rate of melting of the Antarctic ice sheet is 80.0 Gt/a and increasing and contributes 0.22 mm/a to the global sea-level rise; the mass loss rate is 78.3 Gt/a in the West Antarctic and 1.6 Gt/a in the East Antarctic. The average mass loss rate increases from 39.3 Gt/a for the period 2002-2005 to 104.2 Gt/a for the period 2006-2010, and its corresponding contribution to the global sea-level rise increases from 0.11 to 0.29 mm/a, which indicates accelerated ice mass loss over the Antarctic since 2006. Moreover, the mass accumulation rates for Enderby Land and Wilkes Land along the coast of East Antarctica decrease for the period 2006-2008 but increase evidently after 2009.展开更多
黑河流域水储量变化对该区域的生态环境和经济建设等具有重要影响。本文利用2002-08—2011-06的GRACE(gravity recovery and climate experiment)时变重力场模型GRGS-EIGEN-GL04,采用去相关滤波P3M6与300km高斯滤波相结合的滤波方法反...黑河流域水储量变化对该区域的生态环境和经济建设等具有重要影响。本文利用2002-08—2011-06的GRACE(gravity recovery and climate experiment)时变重力场模型GRGS-EIGEN-GL04,采用去相关滤波P3M6与300km高斯滤波相结合的滤波方法反演了黑河流域陆地水储量变化,扣除GLDAS(global land data assimilation system)水文模型计算的土壤水和冰雪变化,给出了黑河流域地下水储量的时空变化,并利用张掖地区23口地下水测井数据对地下水反演结果进行了初步验证。研究结果表明:①黑河流域陆地水储量整体上呈现减少趋势,与该流域气候变化和CPC(Climate Prediction Center)水文模型的计算结果具有较好的一致性,其减少速率为2.3cm/a等效水高;②黑河流域地下水储量呈现长期减少趋势,其减少速率为2.5cm/a等效水高,上、中游区域地下水储量减少速率相当,下游区域地下水储量减少速率明显小于中上游区域。展开更多
The long-term continuous gravity observations obtained by the superconducting gravimeters (SG) at seven globally-distributed stations are comprehensively analyzed. After removing the signals related to the Earth's...The long-term continuous gravity observations obtained by the superconducting gravimeters (SG) at seven globally-distributed stations are comprehensively analyzed. After removing the signals related to the Earth's tides and variations in the Earth's rotation, the gravity residuals are used to describe the seasonal fluctuations in gravity field. Meanwhile, the gravity changes due to the air pressure loading are theoretically modeled from the measurements of the local air pressure, and those due to land water and nontidal ocean loading are also calculated according to the corresponding numerical models. The numerical results show that the gravity changes due to both the air pressure and land water loading are as large as 100×10-9 m s-2 in magnitude, and about 10×10-9 m s-2 for those due to the nontidal ocean loading in the coastal area. On the other hand, the monthly-averaged gravity variations over the area surrounding the stations are derived from the spherical harmonic coefficients of the GRACE-recovered gravity fields, by using Gaussian smoothing technique in which the radius is set to be 600 km. Com-pared the land water induced gravity variations, the SG observations after removal of tides, polar mo-tion effects, air pressure and nontidal ocean loading effects and the GRACE-derived gravity variations with each other, it is inferred that both the ground- and space-based gravity observations can effec-tively detect the seasonal gravity variations with a magnitude of 100×10-9 m s-2 induced by the land water loading. This implies that high precision gravimetry is an effective technique to validate the re-liabilities of the hydrological models.展开更多
基金funded by the Major National Scientific Research Plan(2013CB733305,2012CB957703)the National Natural Science Foundation of China(41174066,41131067,41374087,41431070)
文摘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.
基金supported by the National Basic Research Program of China (Grant No. 2007CB714405)the National Natural Science Foundation of China (Grant No. 40874002)the Program for New Century Excellent Talents in University (Grant No. NCET-07-0635)
文摘It is important to quantify mass variations in the Antarctic ice sheet hybrid filtering scheme employing a combination of the decorrelated to study the global sea-level rise and climate change. A filter P3M6 and 300 km Fan filter was used, and the sur- face mass variations over the Antarctic are recovered from GRACE CSR RL04 monthly gravity field models from August 2002 to June 2010. After deduction of leakage errors using the GLDAS hydrological model and postglacial rebound effects using the glacial isostatic adjustment model IJ05, the variations in the ice sheet mass are obtained. The results reveal that the rate of melting of the Antarctic ice sheet is 80.0 Gt/a and increasing and contributes 0.22 mm/a to the global sea-level rise; the mass loss rate is 78.3 Gt/a in the West Antarctic and 1.6 Gt/a in the East Antarctic. The average mass loss rate increases from 39.3 Gt/a for the period 2002-2005 to 104.2 Gt/a for the period 2006-2010, and its corresponding contribution to the global sea-level rise increases from 0.11 to 0.29 mm/a, which indicates accelerated ice mass loss over the Antarctic since 2006. Moreover, the mass accumulation rates for Enderby Land and Wilkes Land along the coast of East Antarctica decrease for the period 2006-2008 but increase evidently after 2009.
文摘黑河流域水储量变化对该区域的生态环境和经济建设等具有重要影响。本文利用2002-08—2011-06的GRACE(gravity recovery and climate experiment)时变重力场模型GRGS-EIGEN-GL04,采用去相关滤波P3M6与300km高斯滤波相结合的滤波方法反演了黑河流域陆地水储量变化,扣除GLDAS(global land data assimilation system)水文模型计算的土壤水和冰雪变化,给出了黑河流域地下水储量的时空变化,并利用张掖地区23口地下水测井数据对地下水反演结果进行了初步验证。研究结果表明:①黑河流域陆地水储量整体上呈现减少趋势,与该流域气候变化和CPC(Climate Prediction Center)水文模型的计算结果具有较好的一致性,其减少速率为2.3cm/a等效水高;②黑河流域地下水储量呈现长期减少趋势,其减少速率为2.5cm/a等效水高,上、中游区域地下水储量减少速率相当,下游区域地下水储量减少速率明显小于中上游区域。
基金Supported by Knowledge Innovation of Chinese Academy of Sciences (Grant No. KZCX2-YW-133)National Natural Science Foundation of China (Grant Nos. 40730316 and 40574034)Frontier Domain Item of Chinese Academy of Sciences
文摘The long-term continuous gravity observations obtained by the superconducting gravimeters (SG) at seven globally-distributed stations are comprehensively analyzed. After removing the signals related to the Earth's tides and variations in the Earth's rotation, the gravity residuals are used to describe the seasonal fluctuations in gravity field. Meanwhile, the gravity changes due to the air pressure loading are theoretically modeled from the measurements of the local air pressure, and those due to land water and nontidal ocean loading are also calculated according to the corresponding numerical models. The numerical results show that the gravity changes due to both the air pressure and land water loading are as large as 100×10-9 m s-2 in magnitude, and about 10×10-9 m s-2 for those due to the nontidal ocean loading in the coastal area. On the other hand, the monthly-averaged gravity variations over the area surrounding the stations are derived from the spherical harmonic coefficients of the GRACE-recovered gravity fields, by using Gaussian smoothing technique in which the radius is set to be 600 km. Com-pared the land water induced gravity variations, the SG observations after removal of tides, polar mo-tion effects, air pressure and nontidal ocean loading effects and the GRACE-derived gravity variations with each other, it is inferred that both the ground- and space-based gravity observations can effec-tively detect the seasonal gravity variations with a magnitude of 100×10-9 m s-2 induced by the land water loading. This implies that high precision gravimetry is an effective technique to validate the re-liabilities of the hydrological models.
