The northern margin of the East Kunlun Mountains is a distinctive basin and range transition zone characterized by diverse landforms and abundant salt resources. Within this region, the Nalenggele River Catchment is particularly notable for its rich supergene boron deposits and complete hydrological systems including hot springs, rivers, and salt lakes. This region serves as an ideal natural laboratory for studying the boron behavior during regional chemical weathering and migration processes, as well as for understanding boron ore-forming mechanisms in arid basins with alpine-cold environment. However, the sources of dissolved boron in the river and lake waters are still controversial. The relative hydrological and hydrochemical processes have not been quantitatively researched, hindering a comprehensive understanding of boron enriching processes. In this study, the geochemical compositions and boron isotopes of river waters and rock samples in the Nalenggele River Catchment were systematically analysed to understand the formation processes of dissolved boron in rivers and to quantify potential contributions. The results showed: (1) Chemical weathering plays an important role in the formation of dissolved boron in low-boron rivers (<1 mg/L), whereas the enriched boron in high-boron rivers is mainly derived from geothermal waters in the source areas. (2) Geothermal water inputs account for 86.2 % similar to 91.4 % of dissolved boron and lithium in the Hongshui River, a tributary of the Nalenggele River. During the tributary confluence, over 70 % of dissolved boron in the Nalenggele River is contributed by the Hongshui River. (3) Boron isotopes in water are effective for source identification but less reliable for quantitative assessment of boron enrichment processes in the Nalenggele River Catchment due to its fractionation-prone property. This study presents quantitative results of boron sources, contributions, and accumulations and gives an insight into constraints of boron isotope as a geochemical signature. It is expected to provide an enhanced understandings of boron migration, enrichment, and ore-forming processes within "hot spring - river - salt lake" systems of the Tibetan Plateau.

In this study, the stable isotopic and hydrochemical composition of surface water is systematically investigated to reveal the potential sources, influencing factors and chemical weathering processes. Results show that the primary recharge source of surface water is local precipitation, and its isotopic composition influenced by both evaporation effects and altitude effects. Multiple factors can affect the major ion composition in surface water, including the atmospheric precipitation, anthropogenic input, and rock weathering. The average contribution rates from each endmember are 7.17

Danjiangkou Reservoir has been widely concerned as the water source of the world’s longest cross basin water transfer project. Biogenic elements are the foundation of material circulation and key factors affecting water quality. However, there is no comprehensive study on the biogenic elements in tributaries of Danjiangkou Reservoir, hindering a detailed understanding of geochemical cycling characteristics of biogenic elements in this region. Guanshan River, one of the main tributaries that directly enter the Danjiangkou Reservoir, was token as the research object. Spatiotemporal distribution characteristics of basic water quality parameters and biogenic elements were studied. Water quality was comprehensively evaluated through water quality index (WQI). Absolute principal component score-multiple linear regression (APCS-MLR) model was adopted to explore the main sources of biogenic elements. Results showed that, in terms of season, the concentrations of total nitrogen (TN), total phosphorus (TP), and dissolved organic carbon (DOC) were significantly higher in wet season than in dry season, while no significant differences were found for dissolved inorganic carbon (DIC) and dissolved silica (DSi). Spatially, the concentrations of dissolved carbon, DIC, TN, and TP in the middle and lower reaches were higher than that in the upstream. DOC concentration peaked in the middle reaches, while DSi showed higher concentrations in the upstream. WQI values indicated that the river water quality was between good and excellent, although the water quality in wet season was slightly worse than that in the dry season. PCA extracted five potential sources, which accounting for 84.12

The formation of the Jiangsu radial sand ridges (RSRs) in East China has received extensive attention. However, the provenance of the Jiangsu RSRs sediments is still controversial. In this study, the Pb isotopic compositions of residual fractions were used to elucidate the provenance of the Jiangsu RSRs sediments. The results showed that Pb isotopic compositions of sediments in onshore RSRs were not significantly different with those of the landward offshore RSRs, indicating the shoreward transport of sediments from the landward offshore RSRs. The combination of Pb–Nd isotopic compositions revealed that the seaward offshore sediments mainly originated from the Yangtze River Mouth, while the onshore and landward offshore sediments were dominantly supplied by the Old Yellow River Delta through the southward flow. This study provides a deep insight into the evolution of Jiangsu RSRs, and is of great value to the Jiangsu coastal protection.

Accurate modeling of tropospheric delays is crucial for the global navigation satellite system (GNSS), which finds extensive applications in early warning systems of natural hazards and extreme weather forecasting. Zenith tropospheric delay (ZTD) is estimated as a random walk process with a constraint in GNSS processing. The constraint, referred to as random walk process noise (RWPN), holds significant importance in real-time ZTD estimation and exhibits geographical and temporal specificity. Presently, RWPN is treated as either a constant value or derived from a numerical weather model (NWM). To address this, our study presents a global RWPN model (GRM) by parameterizing a decade of NWM-derived RWPN data. Taking into account its spatiotemporal nature, we formulate the RWPN equation for each station by employing trigonometric, exponential, and Legendre functions. The optimum RWPN value is determined by incorporating GRM using latitude, longitude, orthometric height, and time as inputs. To validate the efficacy of GRM, we compare its performance against RWPN values derived from both JRA-55 and ERA5 datasets for the year 2020. The results indicate that the GRM-derived values exhibit enhanced accuracy in comparison with the optimal fixed RWPN values, as well as the yearly and monthly mean RWPN values. Additionally, we assess the efficacy of the GRM model in real-time ZTD estimation across 20 globally distributed GNSS stations. The results reveal an improvement exceeding 10

The water-level fluctuation zone of the lower Jinsha River Basin is a fragile ecosystem with limited water resources in the southwest of China. Soil water is critical for maintaining ecological balance and promoting the healthy development of animals and plants in this region. In this study, eight typical soil profiles were monitored for hydrochemistry in soil-soluble salt from upstream to downstream of the lower Jinsha River Basin. The results show that the soil water content was low and had a negative correlation coefficient with major ions in the soil-soluble phase. The soil-soluble salt is slightly alkaline, and Ca2+, Na+, SO42−, and HCO3− are important components for ions in a soluble phase. Major ions in soluble salt originate from various sources, including precipitation, anthropogenic input, silicate weathering, and carbonate weathering, and the contribution rates from each end member were 0.7%, 45.1%, 25.2%, and 29%, respectively. The ion composition in surface soil soluble salt is mainly influenced by precipitation and human activities, while the ions in the 0–50 cm soil layer originate from the precipitation input and water-rock interaction. In addition, rock weathering is a vital process for releasing ions into soil-soluble salt from 50 to 100 cm soil layer. Our findings provide important references for ion sources and the eco-hydrological process in limited water resources in the water-level fluctuation zone of the lower Jinsha River Basin.

Water vapor over oceans is significant for numerical weather prediction (NWP) and climate research. Ocean platform-based global navigation satellite system (GNSS) which can sense the atmospheric water vapor is becoming an important supplement for water vapor measurements over oceans. However, the application of ocean platform-based GNSS meteorology is normally based on geodetic GNSS receivers, which implies the high cost of hardware. In this contribution, we investigate the potential of retrieving real-time water vapor over oceans with a low-cost receiver (u-blox F9P), and a geodetic GNSS receiver (Trimble NetR9) is also equipped in the experiment vessel. The post-processed Trimble NetR9 zenith total delay (ZTD) estimates and European Centre for Medium-Range Weather Forecasts (ECMWF) ERA5 precipitable water vapor (PWV) products are used for the validation of real-time ZTDs and PWV values. The results show that the real-time ZTDs derived from the low-cost multi-GNSS (GPS + Galileo) observations obtain a difference of over 2.13 cm in root-mean-square (rms) compared to the post-processed ZTDs with an averaged initialization time of approximately 40 min. In addition, compared to ERA5 PWV, the real-time PWV derived from u-blox F9P multi-GNSS observations shows a difference in rms of approximately 4 mm. Although u-blox F9P multi-GNSS performs relatively worse than Trimble NetR9 multi-GNSS in real-time ZTD/PWV estimates, the accuracy of low-cost GNSS receivers derived water vapor over oceans can still meet the requirements for NWP and nowcasting, which demonstrates promising prospects in supplementing the measurements of water vapor over oceans.

Riverine dissolved matter reflects geochemical genesis information, which is vital to understand and manage the water environment in a basin. The Ganjing River located in the hinterland of the Three Gorges Reservoir was systematically investigated to analyze the composition and spatial variation of riverine ions, probe the source and influencing factors, and assess the chemical weathering rates and CO2 consumption. The results showed that the total dissolved solid value (473.31 ± 154.87 mg/L) with the type of “HCO3−–Ca2+” was higher than that of the global rivers’ average. The hydrochemical parameters were relatively stable in the lower reservoir area of the Ganjing River, which was largely influenced by the backwater of Three Gorges Reservoir. The carbonate weathering source contributed 69.63% of TDS (Total dissolved solids), which generally dominated the hydrochemical characteristics. The contribution rates of atmospheric rainfall were relatively low and stable in the basin, with an average of 4.01 ± 1.28%. The average contribution rate of anthropogenic activities was 12.05% in the basin and even up to 27.80% in the lower reservoir area of the Ganjing River, which illustrated that the impoundment of Three Gorges Reservoir had brought great challenges to the water environment in the reservoir bay. The empirical power functions were tentatively proposed to eliminate the dilution effect caused by runoff discharge on the basis of previous studies. Accordingly, the rock weathering rate was calculated as 23.54 t/km2 in the Ganjing River Basin, which consumed atmospheric CO2 with a flux of 6.88 × 105 mol/y/km2. These results highlight the geochemical information of tributaries in the hinterland of the Three Gorges Reservoir, have significant implications for understanding the impact of impoundment, and provide data support for the integrated management of water resources in the Ganjing River Basin.

巴丹吉林沙漠东南部湖泊群是该沙漠重要的水源之一,为揭示湖泊群水体潜在补给来源和补给方式,探索湖泊水体离子空间变化特征及其影响因素,系统分析了该沙漠东南部湖泊群水体δ18 O和δD同位素特征及水化学组成.结果表明:①巴丹吉林沙漠湖泊群水体pH和电导率平均值分别为9.29,291 mS/cm,以Na+和Cl-离子为主,占离子总量比例达69.4％.② 湖泊群水体 δ18 O和 δD同位素平均值分别为6.42‰和-3.67‰,不同区域湖泊群蒸发效应差异显著,湖泊蒸发强度自东南部至西北部逐步增大.③ 基于同位素高程效应方程,研究区湖泊水体潜在补给来源为东南部雅布赖山大气降水,补给方式主要以周边地下水侧向补给为主.补给水源和区域岩石风化是研究区湖泊群水体离子空间变化的主控因素.

干热河谷库区消落带生态修复关键技术难点在于当消落带植被受到长时间淹水与干旱交替双重胁迫时,如何遴选生态修复两栖植物.通过对乌东德库区消落带生态修复试验段淹没前植被调查、溪洛渡库区和三峡库区典型库岸消落带现存植物种群调查以及查阅三峡库区消落带植被自然演替和植被修复相关文献,结合乌东德水电站水位调度节律和库区干热河谷气候条件,对乌东德库区消落带植被自然演替趋势进行了分析.按照自然修复与人工修复相结合、乡土植物与外来植物相结合的消落带生态修复理念,遴选出乌东德库区消落带生态修复试验植物,提出了在试验段沿海拔高程的植物梯度配置模式:消落带中下部配置以狗牙根、香附子、扁穗牛鞭草等为主的多年生草本植物和以苘麻、狗尾草、马唐等为主的一年生草本植物;消落带上部配置以中山杉、水桦、桑树、秋华柳、银合欢等为主的乔、灌木以及草本植物.

消落带土壤水分是制约植物生长发育的关键因素,对库区消落带生态修复意义重大.本文系统分析了乌东德库区消落带修复试验区土壤含水量分布,探索了土壤水分空间变化和影响因素.结果表明:研究区5月水分含量低于5％,不同试验分区和高程区域土壤水分分布受到微地形、土壤特征、植被类型和植被覆盖度等影响.土壤水分随深度变化的主控因素包括地表蒸发和植物吸水,剖面深度大于50 cm的土壤水分是消落带植物潜在利用水源之一.本研究为干热河谷库区消落带土壤水分研究积累了基础资料,为消落带生态修复提供理论参考.

干旱沙漠区水资源是改善生态环境和促进动植物生存的关键.综合古尔班通古特沙漠研究成果,分别对该沙漠气候特征、水分分布和水分来源、水分循环和生态水文过程等方面进行归纳,指出现有研究存在的不足.在此基础上对古尔班通古特沙漠今后研究的方向和内容进行展望,指出将该沙漠不同水体纳入整体研究,以期丰富该沙漠生态水文机制和进一步探讨干旱区水文循环过程.

Atmospheric water vapor plays an essential role in climate change and weather forecasting. However, monitoring water vapor with high spatial and temporal resolutions remains a challenge, especially over ocean regions where observations are insufficient. Shipborne global navigation satellite systems (GNSSs) contribute to enriching water vapor measurements over oceans and also can help validate satellite observations. Due to the lack of long-time serial observations, the performance of shipborne GNSS-derived precipitable water vapor (PWV) is inadequately evaluated on the global ocean scale. In this study, an overall assessment of shipborne GNSS PWV over global oceans is performed based on six voyages from 2014 to 2018. In coastal areas, the PWV differences of shipborne GNSS with respect to (w.r.t.) ground-based GNSS and ground-launched radiosonde data are 2.64 and 2.85 mm in the root mean square (rms), respectively. In open oceans, compared to ship-launched radiosonde profiles and satellite measurements, shipborne GNSS PWV shows the rms of differences of 2.54 and 2.53 mm, respectively. In addition, the rms of PWV differences between the whole track of shipborne GNSS PWV and National Centers for Environmental Prediction (NCEP) Climate Forecast System Version 2 (CFSv2) products is 2.96 mm. The intertechnique validations demonstrate that the accuracy of shipborne GNSS PWV is superior to 3 mm, which meets the requirements of climate research and numerical weather prediction (NWP).

Satellite-borne microwave radiometers provide wet tropospheric correction (WTC) for altimetry observations, which is critical to high-accuracy sea surface height (SSH) measurements. However, it was reported that the Haiyang-2A (HY-2A) calibration microwave radiometer (CMR) experienced abrupt 18.7 GHz band failure. The global navigation satellite system (GNSS) can provide (near) real-time accurate WTC with high temporal resolutions. In this study, GNSS observations of 132 global coastal sites from January 2017 to February 2018 are used for CMR validation and calibration. In addition, the European Centre for Medium-Range Weather Forecasts (ECMWF) products during the same period are also used for comparison. After calibration with GNSS observations, the root-mean-square (RMS) of the WTC differences between CMR and ECMWF decreases from 2.53 to 1.66 cm. After calibration with ECMWF products, the RMS of the WTC differences between ECMWF-calibrated CMR and ECMWF is 1.54 cm. Moreover, different processing strategies of WTC are applied to SSH measurements. The mean sea level anomaly (SLA) values of SSH obtained with ECMWF-calibrated CMR are comparable to those obtained with GNSS-calibrated CMR WTC and with ECMWF WTC. In addition, compared to the SLAs of Jason-3, the SLAs of HY-2A obtained with ECMWF WTC show the smallest differences of 7.79 cm in RMS, which are 0.1 cm smaller than those obtained with ECMWF-calibrated CMR WTC and 0.23 cm smaller than those obtained with GNSS-calibrated CMR WTC. The SLAs obtained with original CMR WTC are reduced by approximately 0.8 cm in RMS after using GNSS-calibrated CMR WTC. Therefore, even with the known limitations of ground-based GNSS (non-collocated measurements over land instead of over ocean), it can indeed serve as a valuable WTC source for radiometer calibration due to the lower latency of GNSS observations.

植物是水库消落带重要组成部分,具有水土保持、污染过滤、物种多样性维持、景观美化等多种生态功能.为系统揭示干热河谷库区消落带植被演替趋势与规律,2019年7月至2020年7月对金沙江干热河谷乌东德库区消落带生态修复试验区水位上涨前的植被现状进行踏查与样方调查,分析了水淹前植物生长现状、特有的植物区系成分和植物种类.研究结果表明:(1)试验地共有维管束植物46科102属112种,其中禾本科、菊科和豆科植物种类最丰富,单科单属现象明显,一年生植物优势明显,具有典型的萨王纳植被特征;(2)群落类型包括车桑子+扭黄茅群落、银合欢+滇刺枣+扭黄茅群落和银合欢纯林群落,结构单一脆弱,人为干扰严重;(3)植物区系成分以热带为主,多为耐旱物种;(4)试验区经历水淹后,原有适应陆生环境的耐旱木本植物物种可能逐步减少,草本植物优势进一步增强,不同生活型植物占比发生改变,具体变化有待后续长期生态监测.研究结果可为后续干热河谷库区消落带生态修复研究与实践提供基础数据与参考依据.

干热河谷是我国西南地区一种特殊的自然景观,生态环境极端脆弱,加之消落带涉及面广,类型复杂,自我修复缓慢,增加了干热河谷生态治理的难度.为明确干热河谷生态治理的发展方向,介绍了干热河谷的基本情况,系统回顾了土壤类型、理化性质、水分分布和植被恢复技术、种类选择以及消落带治理方面的研究进展.目前干热河谷生态治理存在微观研究不够深入、缺乏长期动态监测、生态恢复效益评估指标单一化等不足,亟需应用先进技术手段,合理筛选优良的当地植物种类,建立生态环境长期动态监测与评估体系,加强生态系统自我修复功能,更科学有效地开展干热河谷生态治理.

Sediment deposition has already been considered to be a potential risk to the general running of the Three Gorges Reservoir (TGR). Identifying the sediment sources and their contributions to the TGR is of great significance for the sustainable management of reservoir operation. In this study, surface sediments of the TGR and its main tributaries were sampled in the flood (June to September), dry (November to next February) and even (March to May, October) seasons, 2017-2018, together with surrounding upland soils, and analyzed for Sr-Nd isotopes and rare earth elements (REE). The geochemical results showed that epsilon(Nd)(0) values and Sr-87/Sr-86 ratios of surface sediments from the TGR mainstream varied from - 12.21 to - 9.75 and from 0.720241 to 0.726655, respectively. All sediment and upland soil samples generally showed the LREE enrichment and significant Eu depletions. Three potential sources were identified for the TGR sediments and ranked in the order: regional source (adjacent tributaries) > distal source (upstream tributaries) > proximal source (upland soil), based on the Sr-Nd isotopes and REE parameters. Isotopic mixing model coupled with Monte-Carlo simulations was firstly applied to quantify source contributions to the TGR sediments among different seasons. Through Monte-Carlo model simulations, the regional source contributed approximately 40% to the TGR sediments during the flood and even seasons but approximately 50% during the dry season. The contribution from distal sources arrived at about 30% in the three seasons, and 30% from proximal sources during flood and even seasons and 20% in the dry season. Dam construction was the primary factor affecting the sediment deposition in the TGR, and it would further reduce sediment supply from the distal source with the operation of new increasing dams in the upper Yangtze River Basin. Hence, more attention should be paid to the regional sediment supply of the TGR in the future.

ABSTRACT Shallow groundwater and lake water are the dominant water resources in the Badain Jaran Desert. There are still controversial hypotheses related to the origin of groundwater in this desert. Few studies have been conducted to explore the Sr provenance of these waters and assess the water–rock interactions using a Sr isotope approach until now. In this text, the Sr isotope data of waters in the hinterland of the Badain Jaran Desert and neighbouring areas are reported. The waters in the Badain Jaran Desert have few links to its surrounding rivers, but could be influenced by the precipitation in the Yabulai Mountains. The 87Sr/86Sr ratio changes constantly, while the Sr2+ concentration of shallow groundwater gradually decreases from Yabulai to the desert hinterland to Gurinai-Guaizihu. Combined with hydrochemical data and hydrodynamic conditions, these results show that the dissolved Sr of waters in the desert hinterland is controlled by the Yabulai precipitation and catchment weathering. They further show that the desert shallow groundwater Sr originates mainly from the Yabulai precipitation (> 94 %), while whole-rock weathering contributes little (< 6 %), as calculated using isotope mass balance equations. Relative Sr contributions to lakes from shallow groundwater and catchment weathering are calculated to be 92.5 and 7.5 %, respectively.

金沙江干热河谷是我国重要的水利水电开发区.该区域水电站水库建成运行后将产生大面积库区消落带,严重威胁当地生态环境.本文从金沙江干热河谷水电站库区消落带植被现状、物种筛选、植物生理生态响应、植被恢复模式与技术、恢复生态效益评价等方面概括总结了该区域植被恢复研究进展与现状.针对金沙江干热河谷水电站库区消落带现有植被恢复研究实践不足的现状,提出该区域植被恢复宜根据地形地貌,结合生物技术和工程技术,综合利用多种生活型植物的植被恢复思路,指出金沙江干热河谷水电站库区消落带植被恢复未来研究重点,包括实践与示范、生态系统长期动态监测和管理政策研究等方向.