应用GRACE卫星重力数据计算陆地水变化的相关进展评述

GRACE重力卫星自2002年3月发射至今,已进行了十多年的连续观测,由此获得的重力场变化数据被广泛地应用于研究地表河流及地下水储量变化、南极和格林兰岛冰盖厚度以及全球海平面变化等.本文从GRACE重力卫星数据的处理方法入手,对其数据特点、限制条件和水文模型计算方法等问题进行了系统总结,并针对近年来利用GRACE卫星数据开展的相关研究,从估算全球水储量的变化、区域水储量变化、地下水变化以及陆地河流流域的水储量变化等方面对相关研究和应用进行了简要评述.最后,对使用GRACE卫星数据反演陆地水储量的验证方法和存在的问题进行讨论.本文对于全面了解近年来应用GRACE卫星数据研究陆地水储量变化方面的相关进展具有参考意义.     

利用GRACE时变重力场探测2010年中国西南干旱陆地水储量变化

GRACE(Gravity Recovery And Climate Experiment)卫星计划为监测陆地水储量变化提供了有效技术手段.本文采用2003至2010年共计8年的GRACE月重力场模型反演中国西南区域陆地水储量变化,与GLDAS(Global Land Data Assimilation System)全球水文模型进行对比分析,其结果在时空分布上均符合较好,同时在2009年秋至2010年春该区域陆地水储量均呈现明显减少,与该时段云贵川三省的干旱事件相一致;比较分析了2009年秋至2010年春GRACE反演陆地水储量变化与TRMM(Tropical Rainfall Measuring Mission)合成数据计算的月降雨量的时空分布,两组结果均与西南干旱事件对应时段与区域十分吻合;对近8年的陆地水储量变化与月降雨量数据进行相关性分析,其结果表明陆地水储量变化与降雨量强相关,即降雨量是导致陆地水储量变化的主要因素;分析该区域地表温度变化,结果显示2009年9月至2010年3月地表温度均比历史同期高,地表温度的升高加剧了陆地水储量的减少.     

2005—2017年两次强ENSO事件对中国区域陆地水储量变化影响的卫星重力观测

近年来极端气候事件的频发对全球和区域性水循环产生了重大影响,特别是2005—2017年间两次强ENSO(El Nino-Southern Oscillation)事件使得全球陆地水储量出现了较大的年际波动.GRACE(Gravity Recovery and Climate Experiment)重力卫星随着数据质量的提高、后处理方法的完善和超过十年的连续观测,捕捉陆地水储量异常的能力明显提高,这为研究2005—2017年间两次强ENSO事件对中国区域陆地水储量变化的影响提供了观测基础.本文综合利用GRACE卫星重力数据、GLDAS水文模型和实测降水资料分析了中国区域陆地水储量年际变化和与ENSO的关系.研究发现:长江流域中、下游地区和东南诸河流域与ENSO存在较高的相关性,与ENSO的相关系数最大值分别为0.55、0.78、0.70,较ENSO分别滞后约7个月、5个月和5个月.其中长江流域下游地区与ENSO的相关性最强,2010/11 La Nina和2015/16 El Nino两次强ENSO事件使得陆地水储量分别发生了约-24.1亿吨和27.9亿吨的波动.在2010/11 La Nina期间,长江流域下游地区和东南诸河流域陆地水储量异常约在2011年4—5月达到谷值,而长江流域中游地区晚1~2月达到谷值.在2015/16 El Nino期间,长江流域中、下游地区和东南诸河流域陆地水储量从2015年9月到2016年7月持续出现正异常信号.其中,2015年秋冬季(2015年9月至2016年1月)陆地水储量异常明显是受此次El Nino同期影响的结果;2016年春季(4—5月)陆地水异常是受到此次厄尔尼诺峰值的滞后影响所致;2016年7月的陆地水储量异常则与西北太平洋存在的异常反气旋环流有关.     

基于多源数据分析维多利亚湖流域水储量变化

本文利用CSR发布的GRACE RL06时变重力场模型,结合两种水文模式、卫星测高、降雨和蒸散等多源数据,从多个角度综合系统地分析维多利亚湖流域2003-01-2017-06的陆地水储量变化.比较了正向建模方法和单一尺度因子对泄漏误差的改正效果,经对比采用正向建模方法在此流域效果更好.基于多源数据得出以下三点与此前研究...     

GRACE/GRACE-FO重力卫星揭示近20年河西走廊陆地水储量时空变化

河西走廊由疏勒河流域、黑河流域和石羊河流域组成,水资源保护对河西走廊生态平衡和经济发展有着重要意义.本文利用JPL GRACE/GRACE-FO Mascon模型反演该区域陆地水储量的时空变化,结合GLDAS模型、实测地下水位和冰川水模型等数据对陆地水储量进行水平衡分析及时空特征变化分析,结果表明：(1)2002-04—2020-01间由于降水和冰川融水的补充,疏勒河流域南部和黑河大部分区域陆地水储量空间变化呈上升趋势,而蒸散消耗与农业扩张则导致疏勒河流域北部和石羊河流域陆地水储量下降;(2)通过水平衡研究发现人类耗水是疏勒河流域、黑河流域和石羊河流域陆地水储量变化的重要因素,平均贡献率分别为-24.49%、-47.20%和-43.29%;(3)河西走廊水资源治理政策的实施减少了农业灌溉耗水量、控制了耕地面积的扩张、抑制了地下水储量的消耗.     

GRACE估算陆地水储量季节和年际变化

利用最新公布的GRACE GFZ RL04数据,分析了2003年1月～2007年12月全球27条流域和陆地水储量的季节性和年际变化.结果表明,相近流域季节性变化相位接近.2003年1月～2007年12月陆地水储量季节性变化为1572.4 km3,其中变化最大流域为亚马逊河,其次分别为鄂毕河、尼罗河和尼日尔河等流域.5年来 GRACE陆地水储量的年际变化为-75.4±40.3 km3/a,其中亚马逊河、勒拿河和马更些河等流域的年际变化呈现正增长,而刚果河、密西西比河、恒河、育空河和雅鲁藏布江等流域则相反.GRACE与GLDAS数据均表明2006年后陆地水储量年际变化存在明显增加.     

全球水储量变化的GRACE卫星检测

利用GRACE月尺度变化的地球重力场反演了全球水储量变化,并与陆地水文资料、卫星测高资料及海洋模式得到的结果进行了比对.通过对SOURE台站重力变化的陆地水储量变化计算结果和GRACE重力场系数截断为15阶得到的结果比较,发现两者比较接近,且年周期变化特征明显.对于亚马逊流域,当重力场系数截断为15阶且平滑半径使用106 m时,GRACE反演的区域平均水储量厚度的周年变化振幅为15.6×10-2m,小于使用平滑半径为4×105m的23.7×10-2m.在研究长江流域时,本文对水文资料做球谐系数展开,并与GRACE数据做同样的截断和平滑处理,结果发现GRACE反演的水厚度变化与水文资料结果基本上符合.对于纬度±66°之间的海洋区域,GRACE反演的海水质量变化接近于结合卫星测高和海洋模式得到的结果,但对于2°×2°网格,则在一些区域差异明显,最大超过了0.2 m,中误差为3.8×10-2m.可见,当前GRACE卫星时变重力场只能确定出上千公里及以上尺度区域的水储量变化.     

利用GRACE卫星重力数据监测关中地区地下水储量变化

关中地区作为一带一路重要的工农业发达地区之一,开展针对该地区地下水储量变化的监测和分析工作对揭示地下水储量变化特征与经济社会发展具有重要现实意义.本文基于2003—2014年GRACE卫星重力场模型数据,采用组合滤波及单一尺度因子方法反演了关中地区陆地水储量变化,扣除GLDAS地表水平均结果,对关中地区地下水储量变化进行了监测分析.将陆地水储量变化与GLDAS进行相关性分析,将地下水储量变化与WGHM地下水模型及实测地下水位结果进行对比分析.研究结果表明：①关中地区陆地水变化与GLDAS模型结果具有较强的相关性,相关系数多数大于0.7,其中与模型平均结果的相关系数可达0.8.② 2003—2008年关中地区地下水呈正增长趋势,增加速率为0.25 cm·a^-1,与同期实测数据变化趋势一致;但2003—2013年地下水存在长期亏损,亏损速率为-0.37 cm·a^-1等效水高,这与同时期WGHM估算结果-0.35 cm·a^-1十分吻合.③关中地区地下水存在明显的年变化特征,在2003—2014年期间地下水减少速率为-0.44 cm·a^-1,与该地区降雨量有较好的一致性,在降雨偏少的2008、2012和2013年,地下水也显著减少.     

基于Forward-Modeling方法的黑河流域水储量变化特征研究

黑河流域陆地水储量变化对流域下游等周边区域水资源的合理利用以及经济和社会发展等有着重要的意义.本文利用2003年1月至2013年12月的GRACE RL05数据反演了黑河流域陆地水储量长时间序列的变化,并针对重力场模型和数据处理中产生的信号泄漏问题,采用Forward-Modeling方法进行了改正并恢复泄漏信号;将GRACE获得的泄漏信号恢复前后的黑河流域水储量变化结果与全球水文模型GLDAS和CPC进行比较分析,结果表明泄漏信号改正后的结果与水文模型结果的时间序列相关性均有明显提高,从其空间分布结果可以看出Forward-Modeling方法有效地恢复初始信号、增强被湮没的信号,泄漏信号误差减小;通过分析黑河流域水储量变化的长时间序列结果,发现其具有明显的阶段性变化特征,即2003—2006年呈明显下降趋势,约为-0.86cm·a-1,在2007—2010年趋于平衡状态,而2011—2013年则呈现缓慢上升趋势约为0.14cm·a-1;联合GRACE数据和GLDAS数据反演了黑河流域地下水储量变化,并与全球降雨数据GPCC进行了比较分析,两者相关性可达到0.88以上.     

利用重力卫星GRACE监测亚马逊流域2002-2010年的陆地水变化

本文利用GRACE (Gravity Recovery and Climate Experiment) 卫星重力资料研究了亚马逊流域2002-2010年的陆地水变化,并与水文模式和降雨资料进行了比较分析.在年际尺度上,GRACE结果表明:2002-2003年和2005年,亚马逊流域发生明显的干旱现象;2007年至2009年,陆地水呈逐年增加的趋势,并在2009年6月变化值达到最大,为772±181 km³;自2009年6月至2010年12月,陆地水总量又急剧减少了1139±262 km³,这相当于全球海平面上升3.2±0.7 mm所需的水量.水文模式得到的亚马逊流域陆地水在2010年也表现出明显的减少.降雨资料与GRACE观测资料有很好的一致性.在2005年和2010年的干旱期,亚马逊流域的降雨显著减少,说明降雨是亚马逊流域陆地水变化的重要因素.此外,本文采用的尺度因子的方法有效地降低了GRACE后处理误差的影响.     

Assessment of the WATCLASS hydrological model result of the Mackenzie River basin using the GRACE satellite total water storage measurement

Earlier efforts have been geared towards modelling the hydrological water balance of the Mackenzie River basin and its sub‐basins using a coupled land surface–hydrological model for the Canadian cold region known as WATCLASS. The goal of this current study is to effectively inter‐compare the resulting total water storage anomalies estimated from the gravity recovery and climate experiment (GRACE) satellite analysis with those estimated from the atmospheric‐based water balance approach as well as the model output from WATCLASS over the 1 · 8 × 10⁶ km² Mackenzie River basin in Canada. Since the success of the parameter estimation stage of the coupled land surface–hydrological model, WATCLASS over this large catchment, was entirely based on a goodness of fit between the simulated and observed flows, it is often desirable to assess the reliability of the generated state variables prior to concluding on the overall efficiency of this model in reproducing the relevant hydrological processes over this region. A major challenge here lies in finding suitable dataset with which this comparison can be made to further assess the ability of the model in accurately reproducing other mass fluxes. The outcome of this inter‐comparison reveals the potential application of the GRACE‐based approach as a veritable tool required for the closure of the hydrological water balance of the Mackenzie River basin as well as serving as a dependable source of data for the calibration of traditional hydrological models. Copyright © 2009 John Wiley & Sons, Ltd.     

Seasonal water storage change of the Yangtze River basin detected by GRACE

1 Introduction Large-scale mass redistribution, or temporal varia- tion of mass within the Earth system, the driving force of interactions between solid Earth and geophysical fluids envelope (i.e., atmosphere, ocean, and hydro- sphere), is an important geophysical process critical to human life. Most of the interactions between solid Earth and the atmosphere/oceans happen at seasonal and inter-annual time scales. One important contribu- tor of mass redistribution at seasonal and inter-annual …     

福建水库空间分布特征:沿海密度高水量少、内陆密度低水量多

水库是福建重要的水资源.通过2013-2015年遥感影像结合Google Earth和天地图提取福建水库3353座,分布在81个县区,总面积647.51 km2,约占全省土地面积的0.5%;其中面积≤1 km2水库3248座,总面积197.16 km2,面积1 km2水库105座,总面积450.35 km2.基于经验公式估算总蓄水量188.18亿m3,其中小型水库3078座(91.80%),蓄水总量37.06亿m3(19.69%),大中型水库275座(8.20%),蓄水总量151.12亿m3(80.31%).从空间分布格局来看,福建水库水资源空间分布不均,沿海六市水库密度大于三个内陆市,大中型水库主要分布于福建西北部,蓄水量呈现西北多、东南少的特点.单位陆地面积水库数量沿海城市县区均多于内陆,而单位人口水库数量则相反;单位面积水库蓄水量沿海与内陆差异不大,而人均蓄水量则沿海大部分县区远小于内陆.仅以水库作为供水水源,不能满足沿海地区用水,但内陆地区供水充足.水库蓄水对河流水体的平均滞留时间为0.053~0.341 a,除晋江流域受水库蓄水强烈影响外,其他流域受水库中等程度影响.     

Groundwater Monitoring Using GRACE and GLDAS Data after Downscaling Within Basaltic Aquifer System

Gravity Recovery and Climate Experiment (GRACE) satellite mission is ground-breaking information hotspot for the evaluation of groundwater storage. The present study aims at validating the sensitivity of GRACE data to groundwater storage variation within a basaltic aquifer system after its statistical downscaling on a regional scale. The basaltic aquifer system which covers 82.06% area of Maharashtra state in India, is selected as the study area. Five types of basaltic aquifer systems with varying groundwater storage capacities, based on hydrologic characteristics, have been identified within the study area. The spatial and seasonal trend analysis of observed in situ groundwater storage anomalies (ΔGWSano) computed from groundwater level data of 983 wells from the year 2002 to 2016, has been performed to analyze the variation in groundwater storages in the different basaltic aquifer system. The groundwater storage anomalies (ΔGWSDano) have been derived from GRACE Release 05 (RL05) after removing the soil moisture anomaly (ΔSMano) and canopy water storage anomaly (ΔCNOano) obtained from Global Land Data Assimilation System (GLDAS) land surface models (NOAH, MOSAIC, CLM and VIC). The artificial neural network technique has been used to downscale the GRACE and GLDAS data at a finer spatial resolution of 0.125°. The study shows that downscaled GRACE and GLDAS data at a finer spatial resolution is sensitive to seasonal groundwater storage variability in different basaltic aquifer systems and the regression coefficient R has been found satisfactory in the range of 0.696 to 0.818.     

Quantifying temporal variations in water resources of a vulnerable middle eastern transboundary aquifer system

Freshwater resources in the arid Arabian Peninsula, especially transboundary aquifers shared by Saudi Arabia, Jordan, and Iraq, are of critical environmental and geopolitical significance. Monthly Gravity Recovery and Climate Experiment (GRACE) satellite‐derived gravity field solutions acquired over the expansive Saq transboundary aquifer system were analysed and spatiotemporally correlated with relevant land surface model outputs, remote sensing observations, and field data to quantify temporal variations in regional water resources and to identify the controlling factors affecting these resources. Our results show substantial GRACE‐derived terrestrial water storage (TWS) and groundwater storage (GWS) depletion rates of ?9.05 ± 0.25 mm/year (?4.84 ± 0.13 km³/year) and ?6.52 ± 0.29 mm/year (?3.49 ± 0.15 km³/year), respectively. The rapid decline is attributed to both climatic and anthropogenic factors; observed TWS depletion is partially related to a decline in regional rainfall, while GWS depletions are highly correlated with increasing groundwater extraction for irrigation and observed water level declines in regional supply wells.     

Analysing the contribution of snow water equivalent to the terrestrial water storage over Canada

In this study, the spatial and temporal variabilities of terrestrial water storage anomaly (TWSA) and snow water equivalent anomaly (SWEA) information obtained from the Gravity Recovery and Climate Experiment (GRACE) twin satellites data were analysed in conjunction with multisource snow products over several basins in the Canadian landmass. Snow water equivalent (SWE) data were extracted from three different sources: Global Snow Monitoring for Climate Research version 2 (GlobSnow2), Advanced Microwave Scanning Radiometer-Earth Observing System (AMSR-E), and Canadian Meteorological Centre (CMC). The objective of the study was to understand whether SWE variations have a significant contribution to terrestrial water storage anomalies in the Canadian landmass. The period was considered from December 2002 to March 2011. Significant relationships were observed between TWSA and SWEA for most of the 15 basins considered (53% to 80% of the basins, depending on the SWE products considered). The best results were obtained with the CMC SWE products compared with satellite-based SWE data. Stronger relationships were found in snow-dominated basins (R_s > = 0.7), such as the Liard [root mean square error (RMSE) = 21.4 mm] and Peace Basins (RMSE = 26.76 mm). However, despite high snow accumulation in the north of Quebec, GRACE showed weak or insignificant correlations with SWEA, regardless of the data sources. The same behaviour was observed in the Western Hudson Bay basin. In both regions, it was found that the contribution of non-SWE compartments including wetland, surface water, as well as soil water storages has a significant impact on the variations of total storage. These components were estimated using the Water-Global Assessment and Prognosis Global Hydrology Model (WGHM) simulations and then subtracted from GRACE observations. The GRACE-derived SWEA correlation results showed improved relationships with three SWEA products. The improvement is particularly important in the sub-basins of the Hudson Bay, where very weak and insignificant results were previously found with GRACE TWSA data. GRACE-derived SWEA showed a significant relationship with CMC data in 93% of the basins (13% more than GRACE TWSA). Overall, the results indicated the important role of SWE on terrestrial water storage variations.     

Intercomparison of the total storage deficit index (TSDI) over two Canadian Prairie catchments

Retrieval of the terrestrial moisture storage dataset from the Gravity Recovery and Climate Experiment (GRACE) satellite remote sensing system is possible when the catchment of interest is of large spatial scale. These dataset are of paramount importance for the estimation of the total storage deficit index (TSDI), which enables the characterization of a particular drought event from the perspective of the terrestrial moisture storage over that catchment. Incidentally, the GRACE gravity signal over the 13,000 km² Upper Assiniboine River Basin on the drought-prone Canadian Prairie is so poor therefore making the computation of the total storage deficit index for this basin infeasible. Consequently, the estimation of the terrestrial moisture storage from other reliable sources becomes imperative in order to enable the computation of the TSDI over this basin.This study explores the utilization of the Variable Infiltration Capacity (VIC) model, a physically based, spatially distributed hydrologic model to simulate the total moisture storage over the Upper Assiniboine River Basin which was then employed in the estimation of the TSDI over this basin for subsequent characterization of the recent Prairie-wide drought. Interestingly, the temporal patterns in the computed TSDI from the VIC model reveal a strong resemblance with the same drought characterization undertaken over the larger adjacent Saskatchewan River Basin, which was accomplished utilizing terrestrial moisture storage from the GRACE-based approach. Additionally, these independent techniques employed in the characterization of the last Prairie drought over the two adjacently situated basins resulted in similar drought severity classification from the standpoint of the total moisture storage deficits over these basins. This study has therefore shown that in the computation of the total storage deficit index over small-scale catchments during anomalous climatic conditions that propagate extreme dryness through the terrestrial hydrologic systems, simulations of the total water storage from a structurally sound model such as the VIC model could be resourceful for the computation of the monthly total storage deficit index if no constraint is placed on the availability of accurate meteorological forcing.     

Evaluation of micro-behavior of strain field in Chinese mainland with the GPS time series

Introduction In the last 20 years, with observation technique development in space monitoring to Earth, a large progress has been made in monitoring crustal movement. This makes it possible for us to study crustal movement and the present geodynamic. Continuous GPS observation conducted in Chinese mainland and its neighboring region provides us for studying the present strain field of crustal micro-behavior tectonic. Crustal micro-behavior tectonic means that we can study the dif-ference bet…     

Correction to the crustal thickness of the northwestern China using the data of seis-mic tomography

Introduction The gravity anomaly is an indicator of the density distribution of the underground material. Therefore the gravity anomalies have been important data used for studying the deep crustal struc-ture for a long time. Many people have made detailed researches on the regional crustal structure inverted by Bouguer anomalies. In particular some empirical formulae and practical algorithms about the crustal thickness were brought forward, and a series of results were obtained (MENG, 1996)…