南美巴塔哥尼亚高原位于大型温带冰块快速变化与洋-陆板块俯冲交汇的复杂地质构造区域,其现今冰川均衡调整(GIA)响应信号及地表抬升的机理有待进一步明确。基于重力恢复与气候实验卫星(GRACE)2003—2016年时变重力数据,分析该高原地区的质量变化特征,利用相关水文模型和遥感卫星数据完善该地区的水文模型并提取水文信息空间变化特征,从GRACE综合信号中扣除水文信号得到现今GIA响应信号,并进一步通过全球定位系统(GPS)数据分析GIA效应对地表抬升的贡献。结果表明:巴塔哥尼亚高原地区呈现出巴塔哥尼亚冰原(PIF)及周围区域质量亏损、高原南部和北部质量增加的空间分布特征;水文质量亏损则形成以PIF为中心向外辐射、负信号逐渐减弱的空间分布;GIA响应使高原整体隆升,尤其在PIF南部最为突出,最高达(1.97±0.35) cm/a,与GIA模型特征相似;在北巴塔哥尼亚冰原(NPI)和南巴塔哥尼亚冰原(SPI)GIA响应分别能够解释约69.25%和82.70%的地表抬升信号。
南美巴塔哥尼亚高原位于大型温带冰块快速变化与洋-陆板块俯冲交汇的复杂地质构造区域,其现今冰川均衡调整(GIA)响应信号及地表抬升的机理有待进一步明确。基于重力恢复与气候实验卫星(GRACE)2003—2016年时变重力数据,分析该高原地区的质量变化特征,利用相关水文模型和遥感卫星数据完善该地区的水文模型并提取水文信息空间变化特征,从GRACE综合信号中扣除水文信号得到现今GIA响应信号,并进一步通过全球定位系统(GPS)数据分析GIA效应对地表抬升的贡献。结果表明:巴塔哥尼亚高原地区呈现出巴塔哥尼亚冰原(PIF)及周围区域质量亏损、高原南部和北部质量增加的空间分布特征;水文质量亏损则形成以PIF为中心向外辐射、负信号逐渐减弱的空间分布;GIA响应使高原整体隆升,尤其在PIF南部最为突出,最高达(1.97±0.35) cm/a,与GIA模型特征相似;在北巴塔哥尼亚冰原(NPI)和南巴塔哥尼亚冰原(SPI)GIA响应分别能够解释约69.25%和82.70%的地表抬升信号。
In recent years, frequent flood disasters have posed significant threats to human life and property. From 28 July to 1 August 2023, a basin-wide extreme flood occurred in the Haihe River Basin (23.7 flood). The Gravity Recovery and Climate Experiment satellite can effectively detect the spatiotemporal characteristics of terrestrial water storage anomalies (TWSA) and has been widely used in flood disaster monitoring. However, flood events usually occur on a submonthly scale. This study first utilizes near-real-time precipitation data to illustrate the evolution of the 23.7 extreme flood. We then reconstruct daily TWSA to improve the issues of coarse temporal resolution and data latency and further calculate wetness index (WI) to explore its flood warning. In addition, we analyze soil moisture storage anomalies to provide a comprehensive understanding of flood mechanisms. The study also compares the 2023 floods to a severe flood event in 2021. Results indicate that reconstructed daily TWSA increases by 143.43 mm in 6 days during the 23.7 flood, highlighting the high sensitivity of our approach to extreme events. Moreover, compared to daily runoff data, the WI consistently exceeds warning thresholds 2-3 days in advance, demonstrating the flood warning capability. The flood event 2021 is characterized by long duration and large precipitation extremes, whereas the 2023 flood affects a wider area. This study provides a reference for using daily TWSA to monitor short-term flood events and evaluate the flood warning potential of WI, aiming to enhance near-real-time flood monitoring and support flood prevention and damage mitigation efforts.
利用重力恢复与气候实验卫星(gravity recovery and climate experiment, GRACE)及其后继卫星GRACE-FO(GRACE follow-on)解算的Tongji-Grace2022时变重力场模型,并用卫星测高数据构建高分辨率约束信息,采用两步点质量建模方法解算了西南极冰盖2002-04—2023-12冰川尺度的高分辨率(27 km×27 km)点质量产品。在研究时段内,产品估计的西南极冰盖质量变化趋势为-139.36±19.92 Gt/a,对全球平均质量海平面变化的贡献量为0.38±0.06 mm/a,与三大GRACE官方机构全球点质量产品的估计结果一致,但空间分辨率显著提高。利用独立的输入-输出法产品评估了三大GRACE官方机构产品、卫星测高产品及本产品。结果表明,本产品对西南极20个冰川(组)质量变化趋势估计表现最优,其线性回归系数和R2值分别为0.82和0.93,显著高于其他点质量产品,且截距最小;与卫星测高产品相比,本产品的R2值更高且截距更小,展示出更高的估计精度。研究时段内,西南极冰盖的长期表面物质异常与冰动力相关质量变化率分别为-...
Identifying the changes in terrestrial water storage is essential for a comprehensive understanding of the regional hydrological mass balance under global climate change. This study used a partial least square regression model to fill the observation gaps between GRACE and GRACE-FO and obtained a complete series of terrestrial water storage anomaly data from April 2002 to December 2020 from southeast China. We investigated the variations in terrestrial water storage anomalies in the region and the influencing factors. The study revealed that terrestrial water storage (TWS) anomalies have been increasing in the region, with an average increase of 0.33 cm/yr (p < 0.01). The intra-annual variation showed a positive anomaly from March to September and a negative anomaly in other months. Terrestrial water storage anomalies increased in most regions (especially in the central and northern parts), whereas they decreased in the southern parts. In terms of the components, the soil moisture storage (SMS) contributes 58.3 % and the surface water storage (SWS, especially reservoirs water storage) contributes 41.4 % to the TWS. The study also found that changes in the precipitation explain approximately 71.7 % of the terrestrial water storage variation, and reservoirs contributes to the remaining 28.3 %. These results are essential for understanding the changes in the hydrological cycle and developing strategies for water management in Southeast China.
The southeastern Tibetan Plateau (SETP), which hosts the most extensive marine glaciers on the Tibetan Plateau (TP), exhibits enhanced sensitivity to climatic fluctuations. Under global warming, persistent glacier mass depletion within the SETP poses a risk to water resource security and sustainability in adjacent nations and regions. This study deployed a high-precision ICESat-2 satellite altimetry technique to evaluate SETP glacier thickness changes from 2018 to 2022. Our results show that the average change rate in glacier thickness in the SETP is -0.91 +/- 0.18 m/yr, and the corresponding glacier mass change is -7.61 +/- 1.52 Gt/yr. In the SETP, the glacier mass loss obtained via ICESat-2 data is larger than the mass change in total land water storage observed by the Gravity Recovery and Climate Experiment follow-on satellite (GRACE-FO), -5.13 +/- 2.55 Gt/yr, which underscores the changes occurring in other land water components, including snow (-0.44 +/- 0.09 Gt/yr), lakes (-0.06 +/- 0.02 Gt/yr), soil moisture (1.88 +/- 1.83 Gt/yr), and groundwater (1.45 +/- 0.70 Gt/yr), with a closure error of -0.35 Gt/yr. This demonstrates that this dramatic glacier mass loss is the main reason for the decrease in total land water storage in the SETP. Generally, there are decreasing trends in solid water storage (glacier and snow) against stable or increasing trends in liquid water storage (lakes, soil moisture, and groundwater) in the SETP. This persistent decrease in solid water is linked to the enhanced melting induced by rising temperatures. Given the decreasing trend in summer precipitation, the surge in liquid water in the SETP should be principally ascribed to the increased melting of solid water.
Study region: The Northwest inland basins of China (NWC).Study focus: Terrestrial water resources, especially groundwater resources, are the main source of water for human activities and for maintaining the stability of the ecological environment in NWC. Excessive consumption of water resources will seriously affect the sustainable utilization of water resources and ecological security in this region. Therefore, it is urgent to clarify the long-term changes in water storage in this area in order to handle the pressure of future water re-sources and the natural environment. Using GRACE satellite datasets and global hydrological models (GHMs) products, this study analyzed spatiotemporal variations in terrestrial water storage anomalies (TWSA), groundwater storage anomalies (GWSA), soil moisture, snow water equivalent, and canopy interception combined anomalies (SSCA) in NWC through the application of the water balance, trend decomposition, and empirical orthogonal decomposition methods. Furthermore, the driving factors of water storage change and feasible water resource manage-ment strategies were discussed. New hydrological insights for the region: TWSA in the NWC has experienced a continuous decline over the past nearly 40 years, while SSCA has shown a weak increasing trend (0.03 cm yr-1). Since the availability of glacial retreat data (2003-2016), glacial water storage in the NWC has decreased by 0.09 cm per year, while TWSA, SSCA, and GWSA have changed at rates of -0.25, 0.02, and -0.18 cm yr-1, respectively. The North Tianshan Rivers Basin has become one of the areas with the most severe groundwater depletion in China. 2005-2010 was a turning period in the changes of TWSA, followed by widespread water loss across the NWC. Glacier and snow melt are the most important factors for the decline of TWSA in the Tianshan mountains area, and over -exploitation of groundwater by human activities is a secondary factor. For other regions, Groundwater losses remain the most significant contributor to TWSA losses. The massive loss of water storage in the Tianshan Mountains area, especially the accelerated retreat of glaciers, will affect the stable water supply to the middle and lower reaches of the oasis region, perhaps leading to increased groundwater extraction, which will threaten regional water security and sustainable development. Developing a water-saving society and implementing inter-basin water transfer arefeasible ways to alleviate the water resource crisis. Conducting a comprehensive analysis of all inland rivers in China helps to facilitate horizontal comparisons between various basins, thereby providing more comprehensive insights of water storage fluctuations. The data on water storage changes, extending back to 1980, provide a longer-term perspective on water resource changes in the region, which can contribute to enhancing water resource security and ecological environ-mental protection.
天山北坡位于中国新疆,地处亚欧桥的国门,社会经济发展迅速,其绿洲经济和灌溉农业对地下水资源的依赖程度高。揭示1990—2020年地下水储量的演变规律对维持区域可持续发展具有重要意义。但由于长时序和较高分辨率的区域地下水观测数据匮乏,使得该任务又极具挑战性。本文基于重建的陆地水储量(TWS)变化数据、ERA5-Land再分析数据和其他相关的土壤质地、海拔高程、植被指数和冰川分布等辅助数据,建立了随机森林降尺度模型,据此估算了天山北坡1990—2020年的8 km分辨率地下水储量(GWS)变化,分析了天山北坡GWS的时空演变规律。估算的GWS变化与实测地下水位序列的时间变化具有较高的一致性,二者的相关系数最高达到0.68。天山北坡GWS具有明显的年内变化和年际变化。GWS在夏季和春季较高,在秋季和冬季较低,峰值出现在6月,最低值出现在10月。1990—2020年天山北坡有85%以上的地区GWS发生了显著下降,全区平均的变化趋势为-0.38 cm/a。其中,艾比湖水系和中段诸河区GWS下降最剧烈,额敏河流域下降速率最小;耕地下降速率最大,草地次之,裸地下降速率最小。日益增强的农业耗水活动是1...
重力恢复与气候实验(gravity recovery and climate experiment,GRACE)卫星已成为观测冰盖质量变化的主要手段之一,但不同机构发布的GRACE数据在估计格陵兰冰盖质量变化上存在较大差异,在研究长期变化趋势时会产生很大不一致性。针对此问题,先分析了用不同GRACE数据估算的格陵兰冰盖质量变化数据之间的差异,再用三角帽(three-cornered hat,TCH)方法对其进行不确定性分析,并通过数据融合消除了不同数据间的不一致性。
基于GRACE/GRACE-FO数据,分析了自2002年4月以来格陵兰冰盖的质量变化情况.结果表明:格陵兰冰盖质量经历了亏损较缓(2002-04—2009-12期间约-196±3 Gt/a)到快速亏损(2010-01—2012-12期间约-422±7 Gt/a)、亏损变缓(2013-01—2017-06期间约-170±15 Gt/a)以及再次快速亏损(2018-05—2021-09期间约-297±4 Gt/a)的变化过程.且相比时段2018-09—2020-08(质量亏损速率约-405±8 Gt/a),格陵兰冰盖在2019-09—2021-08的质量亏损速率明显减缓,约-139±7 Gt/a.格陵兰冰盖夏季质量亏损对其年总质量变化起着决定性作用,但2020年其在春、秋和冬季里质量累积量为近年来最大值,这减少了该年质量亏损总量.研究还表明:降水和融水径流是影响格陵兰冰盖质量变化的主导因素.