利用GRACE、GPS和绝对重力数据监测斯堪的纳维亚陆地水储量变化
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摘要
重力卫星GRACE(gravity recovery and climate experiment)监测斯堪的纳维亚半岛陆地水储量变化会受到冰川均衡调整(GIA)信号的严重影响。首先根据该地区绝对重力和GPS并址观测数据计算了GIA重力和垂直位移的实测线性比值,利用该比值和GPS网观测的垂直位移速度场得到了GIA重力。然后,对GRACE观测的重力变化速率进行GIA重力改正,进而可分离陆地水储量变化趋势,避免了使用GIA模型所带来的巨大不确定性,并根据观测数据完整估计了所得结果的不确定性。最后与水文模型作对比分析。结果表明,实测的GIA重力-垂直位移线性比值为0.148±0.020μGal/mm(1Gal=10-2 m/s2),该结果检验了Wahr的理论近似值且与北美实测的结果非常接近。2003年1月至2011年3月期间,斯堪的纳维亚半岛陆地水储量存在明显的增加趋势,信号的主体位于半岛南端的维纳恩湖附近,总的水量增加速率为4.6±2.1km3/a,数据观测期间的累积增加水量为38±17km3。研究结果与WGHM水文模型的结果有较好的一致性,相关系数达到0.69,而与GLDAS水文模型的相关性略小。
Gravity satellite GRACE-derived terrestrial water storage change would be seriously affected by glacial isostatic adjustment(GIA)in Scandinavia.To solve this problem,it is calculated that the measured linear ratio of GIA gravity rates and vertical displacement rates according to the data from collocation stations for absolute gravity and GPS.Using the linear ratio and uplift field derived from GPS observation network,the gravity signal of GIA is got.Gravity change rates from GRACE RL05 data can be corrected for GIA using independent gravity rates derived from GPS vertical velocities,and then it is calculated that corresponding equivalent water thickness in Scandinavia and the uncertainties are evaluated by considering the uncertainties from data.The proposed method utilizes observational data only and can avoid the enormous uncertainty from GIA models.The results are compared with that of two hydrological models.The ratio of gravity versus uplift obtained by ground-based measurements in Scandinavia is 0.148±0.020μGal/mm(1Gal=10-2 m/s2),which validates Wahr's approximate theoretical ratio and is very close to the result from North America.From January 2003 to March 2011,terrestrial water storage shows obvious increase in Scandinavia.The main signal locates at the Vnern lake which is in the southern tip of the peninsula.The rate of total water storage is 4.6±2.1km3/a and the corresponding cumulative quantity is 38±17km3 for the period 2003 to 2011.Results from hydrological models are consistent with the result very well.The correlation coefficient between GRACE and WGHM hydrological model can reach 0.69,while for GLDAS model the correlation coefficient is slightly smaller.
Gravity satellite GRACE-derived terrestrial water storage change would be seriously affected by glacial isostatic adjustment(GIA)in Scandinavia.To solve this problem,it is calculated that the measured linear ratio of GIA gravity rates and vertical displacement rates according to the data from collocation stations for absolute gravity and GPS.Using the linear ratio and uplift field derived from GPS observation network,the gravity signal of GIA is got.Gravity change rates from GRACE RL05 data can be corrected for GIA using independent gravity rates derived from GPS vertical velocities,and then it is calculated that corresponding equivalent water thickness in Scandinavia and the uncertainties are evaluated by considering the uncertainties from data.The proposed method utilizes observational data only and can avoid the enormous uncertainty from GIA models.The results are compared with that of two hydrological models.The ratio of gravity versus uplift obtained by ground-based measurements in Scandinavia is 0.148±0.020μGal/mm(1Gal=10-2 m/s2),which validates Wahr's approximate theoretical ratio and is very close to the result from North America.From January 2003 to March 2011,terrestrial water storage shows obvious increase in Scandinavia.The main signal locates at the Vnern lake which is in the southern tip of the peninsula.The rate of total water storage is 4.6±2.1km3/a and the corresponding cumulative quantity is 38±17km3 for the period 2003 to 2011.Results from hydrological models are consistent with the result very well.The correlation coefficient between GRACE and WGHM hydrological model can reach 0.69,while for GLDAS model the correlation coefficient is slightly smaller.
引文
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[26]汪汉胜,许厚泽,李国营.SNREI地球模型负荷勒夫数数值计算的新进展[J].地球物理学报,1996,39(S1):182-189.WANG Hansheng,XU Houze,LI Guoying.Improvement of Computations of Load Love Numbers of SNREI Earth Model[J].Chinese Journal of Geophysics,1996,39(S1):182-189.
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[29]SWENSON S,CHAMBERS D,WAHR J.Estimating Geocenter Variations from a Combination of GRACE and Ocean Model Output[J].Journal of Geophysical Research,2008,113(B8):B08410.
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[31]CHAMBERS D P.Evaluation of New GRACE Time-variable Gravity Data over the Ocean[J].Geophysical Research Letters,2006,33(17):L17603.
[32]STEFFEN H,WU P,WANG Hansheng.Determination of the Earth’s Structure in Fennoscandia from GRACE and Implications for the Optimal Post-processing of GRACE Data[J].Geophysical Journal International,2010,182(3):1295-1310.
[33]PETTERSEN B R.The Postglacial Rebound Signal of Fennoscandia Observed by Absolute Gravimetry,GPS,and Tide Gauges[J].International Journal of Geophysics,2011:957329.
[34]JAMES T S,IVINS E R.Present-day Antarctic Ice Mass Changes and Crustal Motion[J].Geophysical Research Letters,1995,22(8):973-976.
[35]FANG M,HAGER B H.Vertical Deformation and Absolute Gravity[J].Geophysical Journal International,2001,146(2):539-548.
[36]贾路路,汪汉胜,相龙伟.冰川均衡调整重力与径向位移近似关系的不确定性[J].地球科学:中国地质大学学报,2014,39(7):905-914.JIA Lulu,WANG Hansheng,XIANG Longwei.Uncertainty of Approximate Relationship between GIA Induced Viscous Gravity and Radial Displacement[J].Earth Science-Journal of China University of Geosciences,2014,39(7):905-914.
[37]MILNE G A,DAVIS J L,MITROVICA J X,et al.Spacegeodetic Constraints on Glacial Isostatic Adjustment in Fennoscandia[J].Science,2001,291(5512):2381-2385.
[38]LAMBECK K,PURCELL A,ZHAO J,et al.The Scandinavian Ice Sheet:From MIS 4to the End of the Last Glacial Maximum[J].BOREAS,2010,39(2):410-435.
[39]RODELL M,HOUSER P R,JAMBOR U,et al.The Global Land Data Assimilation System[J].Bulletin of the American Meteorological Society,2004,85(3):381-394.
[40]DLL P,KASPAR F,LEHNER B.A Global Hydrological Model for Deriving Water Availability Indicators:Model Tuning and Validation[J].Journal of Hydrology,2003,270(1-2):105-134.
[2]RODELL M,VELICOGNA I,FAMIGLITTI J S.Satellitebased Estimates of Groundwater Depletion in India[J].Nature,2009,460(7258):999-1002.
[3]WAHR J,SWENSON S,ZLOTNICKI V,et al.Timevariable Gravity from GRACE:First Results[J].Geophysical Research Letters,2004,31(11):L11501.
[4]汪汉胜,王志勇,袁旭东,等.基于GRACE时变重力场的三峡水库补给水系水储量变化[J].地球物理学报,2007,50(3):730-736.WANG Hansheng,WANG Zhiyong,YUAN Xudong,et al.Water Storage Changes in Three Gorges Water Systems Area Inferred from GRACE Time-variable Gravity Data[J].Chinese Journal of Geophysics,2007,50(3):730-736.
[5]FENG Wei,ZHONG Min,LEMOINE J M,et al.Evaluation of Groundwater Depletion in North China Using the Gravity Recovery and Climate Experiment(GRACE)Data and Ground-based Measurements[J].Water Resources Research,2013,49(4):2110-2118.
[6]卢飞,游为,范东明,等.由GRACE RL05数据反演近10年中国大陆水储量及海水质量变化[J].测绘学报,2015,44(2):160-167.DOI:10.11947/j.AGCS.2015.20130753.LU Fei,YOU Wei,FAN Dongming,et al.Chinese Continental Water Storage and Ocean Water Mass Variations Analysis in Recent Ten Years Based on GEACE RL05Data[J].Acta Geodaetica et Cartographica Sinica,2015,44(2):160-167.DOI:10.11947/j.AGCS.2015.20130753.
[7]文汉江,黄振威,王友雷,等.青藏高原及其周边地区水储量变化的独立成分分析[J].测绘学报,2016,45(1):9-15.DOI:10.11947/j.AGCS.2016.20140447.WEN Hanjiang,HUANG Zhenwei,WANG Youlei,et al.Independent Component Analysis of Water Storage Changes Interpretation over Tibetan Plateau and Its Surrounding Areas[J].Acta Geodaetica et Cartographica Sinica,2016,45(1):9-15.DOI:10.11947/j.AGCS.2016.20140447.
[8]罗志才,李琼,钟波.利用GRACE时变重力场反演黑河流域水储量变化[J].测绘学报,2012,41(5):676-681.LUO Zhicai,LI Qiong,ZHONG Bo.Water Storage Variations in Heihe River Basin Recovered from GRACE Temporal Gravity Field[J].Acta Geodaetica et Cartographica Sinica,2012,41(5):676-681.
[9]LETTENMAIER D P,FAMIGLIETTI J S.Hydrology:Water from on High[J].Nature,2006,444(7119):562-563.
[10]MORROW E,MITROVICA J X,FOTOPOULOS G.Water Storage,Net Precipitation,and Evapotranspiration in the Mackenzie River Basin from October 2002to September2009Inferred from GRACE Satellite Gravity Data[J].Journal of Hydrometeorology,2011,12(3):467-473.
[11]PELTIER W R.Global Glacial Isostasy and the Surface of the Ice-age Earth:The ICE-5G(VM2)Model and GRACE[J].Annual Review of Earth and Planetary Sciences,2004,32:111-149.
[12]WANG Hansheng,JIA Lulu,STEFFEN H,et al.Increased Water Storage in North America and Scandinavia from GRACE Gravity Data[J].Nature Geoscience,2013,6(1):38-42.
[13]WAHR J,HAN Dazhong,TRUPIN A.Predictions of Vertical Uplift Caused by Changing Polar Ice Volumes on a Viscoelastic Earth[J].Geophysical Research Letters,1995,22(8):977-980.
[14]LAMBERT A,HUANG J,VAN DER KAMP G,et al.Measuring Water Accumulation Rates Using GRACE Data in Areas Experiencing Glacial Isostatic Adjustment:The Nelson River Basin[J].Geophysical Research Letters,2013,40(23):6118-6122.
[15]DAHLE C,FLECHTNER F,GRUBER C,et al.GFZ GRACE Level-2 Processing Standards Document for Level-2Product Release 0005[R].Potsdam:Deutsches Geo Forschungs Zentrum GFZ,2012.
[16]汪汉胜,贾路路,WU P,等.冰川均衡调整对东亚重力和海平面变化的影响[J].地球物理学报,2010,53(11):2590-2602.WANG Hansheng,JIA Lulu,WU P,et al.Effects of Global Glacial Isostatic Adjustment on the Secular Changes of Gravity and Sea Level in East Asia[J].Chinese Journal of Geophysics,2010,53(11):2590-2602.
[17]MAZZOTTI S,LAMBERT A,COURTIER N,et al.Crustal Uplift and Sea Level Rise in Northern Cascadia from GPS,Absolute Gravity,and Tide Gauge Data[J].Geophysical Research Letters,2007,34(15):L15306.
[18]MAZZOTTI S,LAMBERT A,HENTON J,et al.Absolute Gravity Calibration of GPS Velocities and Glacial Isostatic Adjustment in Mid-continent North America[J].Geophysical Research Letters,2011,38(24):L24311.
[19]STEFFEN H,GITLEIN O,DENKER H,et al.Present Rate of Uplift in Fennoscandia from GRACE and Absolute Gravimetry[J].Tectonophysics,2009,474(1-2):69-77.
[20]MLLER J,NAEIMI M,GITLEIN O,et al.A Land Uplift Model in Fennoscandia Combining GRACE and Absolute Gravimetry Data[J].Physics and Chemistry of the Earth,Parts A/B/C,2012,53-54:54-60.
[21]JOHANSSON J M,DAVIS J L,SCHERNECK H G,et al.Continuous GPS Measurements of Postglacial Adjustment in Fennoscandia 1.Geodetic Results[J].Journal of Geophysical Research,2002,107(B8):2157.
[22]LIDBERG M,JOHANSSON J M,SCHERNECK H G,et al.An Improved and Extended GPS-derived 3DVelocity Field of the Glacial Isostatic Adjustment(GIA)in Fennoscandia[J].Journal of Geodesy,2007,81(3):213-230.
[23]LIDBERG M,JOHANSSON J M,SCHERNECK H G,et al.Recent Results Based on Continuous GPS Observations of the GIA Process in Fennoscandia from BIFROST[J].Journal of Geodynamics,2010,50(1):8-18.
[24]WAHR J,MOLENAAR M,BRYAN F.Time Variability of the Earth’s Gravity Field:Hydrological and Oceanic Effects and Their Possible Detection Using GRACE[J].Journal of Geophysical Research,1998,103(B12):30205-30229.
[25]WANG Hansheng,WU P,WANG Zhiyong.An Approach for Spherical Harmonic Analysis of Non-smooth Data[J].Computers&Geosciences,2006,32(10):1654-1668.
[26]汪汉胜,许厚泽,李国营.SNREI地球模型负荷勒夫数数值计算的新进展[J].地球物理学报,1996,39(S1):182-189.WANG Hansheng,XU Houze,LI Guoying.Improvement of Computations of Load Love Numbers of SNREI Earth Model[J].Chinese Journal of Geophysics,1996,39(S1):182-189.
[27]鞠晓蕾,沈云中,张子占.基于GRACE卫星RL05数据的南极冰盖质量变化分析[J].地球物理学报,2013,56(9):2918-2927.JU Xiaolei,SHEN Yunzhong,ZHANG Zizhan.Antarctic Ice Mass Change Analysis Based on GRACE RL05Data[J].Chinese Journal of Geophysics,2013,56(9):2918-2927.
[28]CHENG Minkang,TAPLEY B D.Variations in the Earth’s Oblateness During the Past 28Years[J].Journal of Geophysical Research,2004,109(B9):B09402.
[29]SWENSON S,CHAMBERS D,WAHR J.Estimating Geocenter Variations from a Combination of GRACE and Ocean Model Output[J].Journal of Geophysical Research,2008,113(B8):B08410.
[30]贾路路,汪汉胜,相龙伟,等.冰川均衡调整对南极冰质量平衡监测的影响及其不确定性[J].地球物理学报,2011,54(6):1466-1477.JIA Lulu,WANG Hansheng,XIANG Longwei,et al.Effects of Glacial Isostatic Adjustment on the Estimate of Ice Mass Balance over Antarctica and the Uncertainties[J].Chinese Journal of Geophysics,2011,54(6):1466-1477.
[31]CHAMBERS D P.Evaluation of New GRACE Time-variable Gravity Data over the Ocean[J].Geophysical Research Letters,2006,33(17):L17603.
[32]STEFFEN H,WU P,WANG Hansheng.Determination of the Earth’s Structure in Fennoscandia from GRACE and Implications for the Optimal Post-processing of GRACE Data[J].Geophysical Journal International,2010,182(3):1295-1310.
[33]PETTERSEN B R.The Postglacial Rebound Signal of Fennoscandia Observed by Absolute Gravimetry,GPS,and Tide Gauges[J].International Journal of Geophysics,2011:957329.
[34]JAMES T S,IVINS E R.Present-day Antarctic Ice Mass Changes and Crustal Motion[J].Geophysical Research Letters,1995,22(8):973-976.
[35]FANG M,HAGER B H.Vertical Deformation and Absolute Gravity[J].Geophysical Journal International,2001,146(2):539-548.
[36]贾路路,汪汉胜,相龙伟.冰川均衡调整重力与径向位移近似关系的不确定性[J].地球科学:中国地质大学学报,2014,39(7):905-914.JIA Lulu,WANG Hansheng,XIANG Longwei.Uncertainty of Approximate Relationship between GIA Induced Viscous Gravity and Radial Displacement[J].Earth Science-Journal of China University of Geosciences,2014,39(7):905-914.
[37]MILNE G A,DAVIS J L,MITROVICA J X,et al.Spacegeodetic Constraints on Glacial Isostatic Adjustment in Fennoscandia[J].Science,2001,291(5512):2381-2385.
[38]LAMBECK K,PURCELL A,ZHAO J,et al.The Scandinavian Ice Sheet:From MIS 4to the End of the Last Glacial Maximum[J].BOREAS,2010,39(2):410-435.
[39]RODELL M,HOUSER P R,JAMBOR U,et al.The Global Land Data Assimilation System[J].Bulletin of the American Meteorological Society,2004,85(3):381-394.
[40]DLL P,KASPAR F,LEHNER B.A Global Hydrological Model for Deriving Water Availability Indicators:Model Tuning and Validation[J].Journal of Hydrology,2003,270(1-2):105-134.