| Glaciers are not only the most valuable freshwater in the Earth, but also a good sensitive indicator of global climate change. With global warming, most of the mountain glaciers keep on melting for decades, especially in the Tibetan Plateau (TP), known as the "Asia water tower". Moreover, the mountain glaciers change is not only an important impact on river runoff, but also reveals the plateau climate patterns, so there is an important meaning of study TP glaciers change to understand of future climate change and glacier runoff. Furthermore, TP has an important influence on water resources supply in the region of the Yangtze River basin where is it originated. Yangtze River basin as China's important economic and political regions, with the rapid social and economic development, the water resources supply will be a very prominent constraints. There is an important scientific and practical meaning of study the issues about the water storage change and future water resources sustainable utilization in the Yangtze River basin.There are deficiencies by the traditional measurement methods (glaciological measurements, the cumulative area ratio method, hydrology methods, etc.) to determine the glaciers mass change, which are relatively short-termed, difficult access to generally remote glaciers, rely heavily on the availability of glaciological mass balances during various years, and need hydrological observations; the limitations of traditional hydrological observations which are low resolution, difficult to make a wide range of large-scale accurate quantitative assessment; the critical issues of GRACE satellites which are low spatial resolution, aliasing effects, leakage effects, difficult to validate and separate signals, Glacial Isostatic Adjustment (GIA) effects and so on. In this contribution, the theory, model, algorithm and key technologies for determining surface mass change by combination space technology and ground-based observations data. In order to overcome the key difficulties mentioned above, several new strategies, models and methods are proposed. The main innovative contributions are listed below:(1) Research on the theory and method determine the Earth's surface mass transport from GRACE data. Firstly, the formulas for the potential theory, mascon, point-mass modeling, spherical harmonic coefficients fitting, optimized forward model are derived independently and given the advantages and disadvantages of these methods; Secondly, we deeply study the post-processing methods of GRACE which include the Gaussian filter, Wiener filter, improved Gaussian filter, Fan filter, EOF filter, RMS (Root Mean Square) filter, moving windows decorrelation filer, moreover, a new filter is devised named 'Non-isotropic combination filter' which showed a better performance; Thirdly, the signal separation method, forward modeling technique, nonlinear programming, four steps and scale factor are derived independently to correct leakage; Fourth, we propose the Pel-5-VM4-R model to correct GIA effects in China which based on the ten models to derive the global GIA effects; Finally, the function model of the terrestrial water storage changes signals obtained based on the GRACE satellite data is proposed, which included the seasonal signals (annual and semi-annual), S2 tidal alias (cycle:161 days), K2, tidal alias (cycle:3.73 years), and trend and acceleration signals.(2) Because the spatial resolution of GRACE is on the order of few hundred kilometers, the Multi-Lagrange multiplier method which can be minimized the effects of GRACE observational errors and reduced the leakage errors in the large area is proposed, which shows better than Gaussian smoothing kernel in reduced the leakage errors and determined the large surface mass change. Moreover, to infer the water storage change in Yangtze River and its main tributaries on Multi-Lagrange multiplier method and compare with hydrological data show that they have high correlation coefficient and coincide with each other.(3) The total terrestrial water storage anomalies (TWSA) in Yangtze River basin is inferred by Multi-Lagrange multiplier method from GRACE, and applied a time-lagged autoregressive model of river discharge to study the flood potential of Yangtze River basin, which show that the inclusion of GRACE-based total water storage information allows us to assess the predisposition of a river basin to flooding as much as 3-6 months in advance. We conclude that basin-scale estimates of water storage derived from satellite observations of time-variable gravity can be provided a new and effective tool for characterizing regional flood potential.(4) The TWSA in southwestern China is inferred by Lagrange multiplier method from GRACE, and assessed hydrological drought characterization, which shows the GRACE has the ability to detect the terrestrial water storage changes in southwestern China which are caused by drought events. Also, the Non-seasonal water storage deficit can further quantify the drought characteristics, and thereby provide a useful new tool for the research of hydrological drought events.(5) The correlation between the TWSA in Yangtze, the runoff in Datong station, precipitation and ENSO are given, which shows the Yangtze River basin of precipitation, river runoff and the TWSA reduced before summer in El Nino year that mean it is likely to occur drought, otherwise flood. To monitor and predict El Nino has great significance on preventing floods and drought in Yangtze River Basin.(6) The method of monitoring TP glaciers mass change by combination remote sensing data which include Landsat 7, CGI, Google, ICESat and SRTM is proposed and given the detailed flow of calculation which include determined the glacier footprints, the preprocessed of ICESat and three correlated methods of SRTM, which is successful research for Karakoram and Eastern TP (ETP) glaciers elevation change.(7) Positive glacier-mass balance in the Karakoram is verified by combination with GRACE, GPS, precipitation and the hydrological station observations surrounding Karakoram river systems. Moreover, The cause of glacier in the Karakoram stable and advancing is firstly given by combination with CAM and CLM, which is large evaporation loss of mass in the middle east transfer to the Karakoram by the strengthening of the role of westerly winds and formed snow, then make the glacier increased.(8) The glaciers elevation change of ETP, Gel (sub-areas:A, B, C), Tang (sub-areas: A, B, C, D, E, F) and HDS (sub-area:A) are proposed by combination remote sensing data which include Landsat 7, CGI, Google, ICESat and SRTM show that the Gel, Tang and HDS glaciers are rapidly melting, especially in the sub-area A of HDS.(9) ETP glaciers contributions to the Yangtze River basin water storage are given by geodesy and hydrology method, which show ETP glaciers are rapidly melting, the Yangtze River basin water storage change is increasing and have a moderate negative correlation with each other, ETP glaciers contributions to the Yangtze River basin water storage close to 20% and Tang 15.35%, the normalized melt index (NMI) is 0.25 by hydrological observation data, the Ping Shan and Datong hydrological stations data show that the precipitation of the upper reaches of the Yangtze River (Jinsha River) and the entire Yangtze River basin are consistent with each other and slowly increasing in 2003-2010.(10) Here, we propose that the Yangtze River has been a seasonal river. The water storage is mainly from precipitation and secondly from TP glacier melting water. |
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