The Tienshan Mountains of Central Asia, a key region in global arid and semi-arid zones, faces highly uneven precipitation distribution due to its unique topography and climate. While extreme heavy precipitation has been widely studied, research on extreme light precipitation is limited. Additionally, spatial distribution patterns and driving mechanisms of extreme events under varying climatic and geomorphic conditions remain underexplored. This study systematically examines the spatial-temporal trends of extreme hydro-climatic events, focusing on both extreme heavy and light precipitation, to provide insights for water resource management and disaster prevention. A distinct hydrological regime shift has occurred since 2000. The frequency anomaly of extreme light precipitation events (R1p) plunged from positive to negative, indicating a marked decline, whereas extreme heavy precipitation events (R99p) surged, reflecting a substantial increase in frequency. Spatially, a prominent dipole pattern is identified around 80 degrees E, where extreme heavy precipitation frequency increases eastward and decreases westward. Vertically, the mid-altitude zone acts as an amplification center, exhibiting the sharpest intensification of heavy precipitation and the steepest decline in light precipitation frequency. These patterns result from the combined effects of Tibetan Plateau thermal dynamics and monsoon-driven moisture transport, creating distinct differences in extreme precipitation between the eastern and western Tienshan. Future studies should explore the interactions between the plateau and atmospheric circulation to improve the prediction and mitigation of extreme events, aiding water resource management and disaster preparedness.

Changes in precipitation variability not only have a significant impact on water cycle processes, but also pose an additional challenge to society's climate resilience. Extreme precipitation is more severe, more abrupt, and more sensitive to temperature changes than mean-state precipitation. However, our understanding of the features of extreme precipitation variability over a broad range of temporal scales, as well as the differences between wet and dry seasons, is limited. In this study, we perform filtering on a daily (2-5 days) to an interannual (2-8 years) scale, using daily precipitation data from detrended APHRODITE and bias-corrected CMIP6 based on zero-phase Butterworth filters. We then analyze the changes in climatological extreme precipitation variability at different time scales, looking at the features along geographical gradients and in wet and dry seasons. At various warming levels, extreme precipitation variability is projected. The findings reveal that the longer the time scale, the higher the overall variability of both extreme and mean-state precipitation, with extreme precipitation showing greater variability. From daily to interannual scales, the variability of R95p increases from 142.79 mm to 875.05 mm, representing a 6.13-fold increase in volatility, but the variability in mean precipitation increases just 1.43-fold, from 2.27 mm to 3.24 mm. The variability in the eastern Tienshan Mountains (80 degrees E - 95 degrees E) is greater than that in the western Tienshan Mountains (66 degrees E - 80 degrees E). Furthermore, along longitudinal and latitudinal gradients, extreme precipitation variability exhibits considerable time-scale differences, with the more extreme the event, the greater the variability. R10mm variability increases from 15.28 d to 76.74 d on a daily to interannual scale. The variability increase (61.46 d) is roughly twice that for R5mm. Seasonally, the wet season is more variable than the dry. The total variability of R10mm was 4.57 days in the wet season and 1.78 days in the dry season. Compared with the reference period (1976-2005), there is an overall increase in extreme precipitation variability at different warming levels, along with an increasing sensitivity to temperature. With the exception of consecutive dry days, the degree of response of filtered extreme precipitation variability to temperature (absolute value of response rate) shows obvious increases with time scale and accounts for a greater proportion of the total variability response rate.

Under global warming, extreme hydrological events are experiencing increasingly violent fluctuations. Investigating changes in the intensity and frequency of extreme precipitation (EP) events is particularly critical for understanding the hydrological response to climate change. Based on high-precision and long-term daily grid precipitation data obtained from Asian Precipitation-Highly Resolved Observational Data Integration Towards Evaluation of Water Resources (APHRODITE), 25 EP indices were examined for the Tienshan Mountains region of Central Asia (TMCA). Here, the relationship between EP and associated large-scale climate teleconnections is revealed by using a series of approaches such as trend analysis and the geographical detector method (GMD), a statistical tool to measure and attribute spatial stratified heterogeneity. The results show an overall increase in EP during 1951-2014, as reflected in the 25 indices. Furthermore, the number of consecutive dry days (CDD) decreased from 87.02 to 69.35 while the number of consecutive wet days (CWD) increased from 3.89 to 4.61. Meanwhile, the increasing trend of total precipitation (PRCPTOT) was 18.43 mm/10a, and changes in EP frequency were shown to increase with event rareness. For R95p, the observed changes in frequency are 34.46%, but these jump to 96.58% for R99p. Moreover, the study also notes that changes in EP are elevation-dependent, with middle altitude areas (1500-3500 m) being most sensitive to change rates. As well, the study reveals that the occurrence of EP responds non-linearly to climatic teleconnections, and that the combined effect of two factors generally make much larger contributions to EP than the summation of individual factors. Further analyses indicate strong zonal circulation at 500 hPa, 1000 hPa potential height increases airflow from west to east. And the weakening of the East Asian Summer Monsoon accompanied by the westward extension of the western Pacific subtropical high and the increase in Mongolian anticyclone activity all bring sufficient exogenous water vapor from the North Atlantic and Indian Ocean to the TMCA.

This paper investigates the performance of bias-corrected Flexible Global Ocean-Atmosphere-Land System-g3 (FGOALS-g3) model products and then detects changes in extreme precipitation (EP) in the Tienshan Mountains, Central Asia (TMCA), as reflected by 25 EP indices. The reliability of the FGOALS-g3 model outputs is assessed systematically based on multiple statistical indicators against multi-source precipitation datasets and the bias -corrected FGOALS-g3 model products are applied to project EP variations under different global warming levels. Using the geographical detector method, a novel statistical method for detecting spatial heterogeneity and elucidating the underlying causes, the explanatory power of 20 atmospheric circulation factors related to EP is examined. The findings indicate that while the FGOALS-g3 products can detect the spatial pattern of multi-year average precipitation in the TMCA, there is an obvious overestimation in magnitude, especially in the West and Middle Tienshan Mountains. These biases are significantly reduced, however, after downscaling and bias correction. Compared with the Asian Precipitation Highly-Resolved Observational Data Integration Towards Evaluation (APHRODITE) data, the grid-by-grid error in bias-corrected FGOALS-g3 simulated mean precipitation is between-7.64% and 10.95%. In terms of EP, the corrected FGOALS-g3 products not only reproduce the spatial distribution, but also reasonably simulate their magnitudes, with some overestimation in light EP and underestimation in heavy EP. Overall, across the historical period, EP has increased. The intensity and frequency of EP are projected to generally increase under different scenarios. At 1.5 degrees C warming levels, annual total pre-cipitation in wet days (PRCP) increases by 5.74% (7.74%) under the SSP245 (SSP585). Additionally, as an EP becomes rarer, its rate of change rises. The main driving factors in EP are detected to be 30 hPa zonal wind (30ZW), relative number of sunspots (SF), south Asian summer monsoon (SAM), sea surface temperature anomaly in the region of 5 degrees S-5 degrees N, 170 degrees-120 degrees W (NINO 3.4), and mean surface temperature (T).

The Tienshan Mountains is the main water source and ecological barrier in the central portion of the Silk Road Economic Belt, a new economic development zone with the Asia-Pacific Economic Circle to the east and the European Economic Circle to the west. Production-living-ecological activities in the arid Central Asia region are heavily dependent on water resources mainly recharged from melt and alpine precipitation. Hence, reliable projections of changes in extreme precipitation under global warming are particularly important for the utilization and management of water resources. Based on the downscaled and bias-corrected state-of-art global climate models from the Coupled Model Intercomparison Project Phase 6 (CMIP6), we investigate changes in extreme precipitation over the Tienshan Mountains, Central Asia (TMCA) under different levels of global warming (1.5 degrees C, 2.0 degrees C, 3.0 degrees C, and 4.0 degrees C). We specifically assess the robustness of changes and the benefits of limiting warming to 2.0 degrees C as opposed to 3.0 degrees C. Compared with the reference period (1976-2005), a robust change in extreme precipitation across the TMCA is expected for all warming levels. And the fraction of land faced a robust change also increases with warming levels. Furthermore, there would be a substantial rise in extreme impacts in the TMCA when shifting from increases of 2.0 degrees C to 3.0 degrees C. In a scenario involving a 1.0 degrees C rise (i.e., from 2.0 degrees C to 3.0 degrees C), nearly 85.70 % and 60.19 % of the land in the TMCA will be affected by a robust increase in annual total wet-day precipitation (PRCPTOT) and number of light rain days (RSmm), respectively. In the same scenario, areas affected by robust changes in duration indices (consecutive dry days [CDD] and consecutive wet days [CWD]) will likely be less than 11.59 %. Limiting warming to 2.0 degrees C instead of 3.0 degrees C can avoid a marked increased impacts of about 62.84 %similar to 153.77 % of the change in frequency, intensity, and duration of extreme precipitation.

Intense human activities in arid areas have great impacts on groundwater hydrochemical cycling by causing groundwater salinization. The spatiotemporal distributions of groundwater hydrochemistry are crucial for studying groundwater salt migration, and also vital to understand hydrological and hydrogeochemical processes of groundwater in arid inland oasis areas. However, due to constraints posed by the paucity of observation data and intense human activities, these processes are not well known in the dried-up river oases of arid areas. Here, we examined spatiotemporal variations and evolution of groundwater hydrochemistry using data from 199 water samples collected in the Wei-Ku Oasis, a typical arid inland oasis in Tarim Basin of Central Asia. As findings, groundwater hydrochemistry showed a spatiotemporal dynamic, while its spatial distribution was complex. TDS and δ18O of river water in the upstream increased from west to east, whereas ion concentrations of shallow groundwater increased from northwest to southeast. Higher TDS was detected in spring for shallow groundwater and in summer for middle groundwater. Pronounced spatiotemporal heterogeneity demonstrated the impacts of geogenic, climatic, and anthropogenic conditions. For that, hydrochemical evolution of phreatic groundwater was primarily controlled by rock dominance and evaporation-crystallization process. Agricultural irrigation and drainage, land cover change, and groundwater extraction reshaped the spatiotemporal patterns of groundwater hydrochemistry. Groundwater overexploitation altered the leaking direction between the aquifers, causing the interaction between saltwater and freshwater and the deterioration of groundwater environment. These findings could provide an insight into groundwater salt migration under human activities, and hence be significant in groundwater quality management in arid inland oasis areas.

植被总初级生产力(Gross primary productivity,GPP)是陆地生态系统碳循环的关键环节,对维持全球碳平衡至关重要.基于Google Earth Engine平台,利用NASA LP DAAC发布的MOD17A2H产品,研究分析了塔里木河生态输水期间陆地生态系统生长季的GPP变化.结果表明:(1)生态输水后,塔里木河生态环境整体得到改善.输水前期,塔里木河生长季GPP平均为3675.51 g C·m-2·季-1,输水中期,生长季GPP增加到4024.09 g C·m-2·季-1,输水后期,该值跃升为4896.61 g C·m-2·季-1.2000—2020年塔里木河生长季GPP表现出明显的增加趋势,增长幅度约为每个生长季增加90.25 g C·m-2.2010年后,上、中、下游日GPP增加幅度亦更明显,分别为每10 a增加2.54 g C·m-2、2.17 g C·m-2和1.74 g C·m-2.(2)塔里木河陆地生态系统生长季(5—10月)的日GPP变化在不同区域存在明显差异.上游区日GPP变化总体上表现出先增加后减小的单峰趋势,下游区则以双峰变化趋势为主.(3)塔里木河生态输水工程有益于生长季GPP的变化,其中对6、8月的GPP变化影响更显著.

分析了开都河-黄水沟-大湖区-小湖区连通工程实施后博斯腾湖矿化度的时空变化及其驱动因素,以期为进一步改善博斯腾湖水环境提供科学指导.结果表明:空间变化上,水系连通工程促进了博斯腾湖大、小湖区水循环,改善了博斯腾湖矿化度,使黄水沟河道(南大闸)矿化度降低了0.5～1.0 g/L、大湖区西北角和东南部矿化度降低了0.3～0.5 g/L、小湖区东部矿化度降低了0～1.5 g/L;时间变化上,博斯腾湖黄水沟区、西岸区、大湖区和小湖区矿化度变化具有较高的同步性;水系连通工程的实施对改善博斯腾湖矿化度空间分布作用显著;高矿化度水体的扩散和湖水水位,尤其是水温等因素共同驱动了矿化度随时间的变化.在水系连通工程实施下,科学调控年内入湖、出湖水量并严格阻止污水入河、入湖是改善博斯腾湖矿化度的关键.

Studying the relationship between agricultural irrigation water requirements (IWR) and water supply is significant for optimizing the sustainable management of water resources in Tarim River Basin (TRB). However, the related studies have not quantified the total IWR and the imbalance of irrigation water supply and requirements in the TRB. The study analyzed the spatial-temporal variations of IWR by a modified Penman–Monteith (PM) method during 1990–2015. Five major crops—rice, wheat, maize, cotton, and fruit trees—are chosen for calculating the IWR. It was found that the IWR increased significantly, from 193.14 × 108 m3 in 1990 to 471.89 × 108 m3 in 2015, for a total increase of 278.74 × 108 m3. For the first period (1990–2002), the total IWR remained stable at 200 × 108 m3 but started to increase from 2003 onwards. Significantly more irrigation water was consumed in the oasis regions of the Tienshan Mountains (southern slope) and the Yarkand River (plains). Furthermore, there was an intensified conflict between IWR and water supply in the major sub-basins. The ratios of IWR to river discharge (IWR/Q) for the Weigan-Kuqa River Basin (WKRB), Aksu River Basin (ARB), Kaxgar River Basin (KGRB), and Yarkand River Basin (YRB) were 0.93, 0.68, 1.05, and 0.79, respectively. The IWR/Q experienced serious annual imbalances, as high flows occurred in July and August, whereas critical high IWR occurred in May and June. Seasonal water shortages further aggravate the water stress in the arid region.

研究胡杨叶片气孔特征有助于解读干旱胁迫环境下的水分利用特征和抗旱机理。本文选取塔里木河下游英苏、阿拉干、依干布及麻3个典型断面,以胡杨为研究对象,探讨不同干旱胁迫梯度下胡杨叶片气孔密度与气孔长度的变化规律,分析胡杨雌、雄株在干旱胁迫下的响应差异。结果显示:（1）胡杨叶片气孔密度随干旱胁迫程度的增加呈上升趋势,而叶片气孔长度随干旱胁迫程度的加大呈减小趋势;（2）干旱胁迫环境下,胡杨雌、雄株叶片的气孔密度和气孔长度的变化率存在一定差异,表现为在干旱胁迫环境下,胡杨雄株的叶片下表皮气孔密度增长率较小,而胡杨雌株叶片的下表皮气孔长度负增长率显著大于雄性的下表皮;（3）胡杨叶片气孔密度和长度的变化反映胡杨雌、雄株的抗干旱能力,从胡杨叶片的气孔密度与气孔长度的变化结果显示,在干旱胁迫环境下,胡杨雄株的保水能力和耐受能力强于雌株。

采用平板稀释法、紫外分光光度法、NaHCO3浸提-钼锑抗显色法等方法对伊犁大小西沟野生樱桃李下发育土壤的速效氮、速效磷、过氧化氢酶、蔗糖酶、微生物个数及土壤粒度进行了研究.结果表明,研究区土壤的速效氮含量约3.87 mg·kg-1,速效磷含量约17.89 mg·kg-1,二者在垂直方向上均呈现随土层深度的增加而逐渐减少的规律.研究区土壤中的微生物数量变化范围在0～5 000个,均值约2 217个.在垂直方向上,微生物个数与土层深度呈现出显著的负相关性.研究区土壤下的过氧化氢酶活性约为8.26 mg·g-1·min-1,蔗糖酶活性约0.22 mg·g-1,二者在垂直方向上均随土层深度的增加呈明显减少趋势.研究区内的土壤粒级以粉粒、砂粒居多,平均粒径约50.01 μm.土粒不均匀,分选性极差,粒度频率曲线很尖锐,呈极正偏.研究区土壤的速效磷与速效氮、蔗糖酶、过氧化氢酶、微生物个数之间呈现显著的正相关关系,相关系数依次为0.983,0.992,0.960,0.917.野生樱桃李下土壤速效氮及粘粒含量的偏少,微生物数量、过氧化氢酶及蔗糖酶的下降可能是导致野生樱桃李退化的一个原因.