中巴喀喇昆仑公路冰湖溃决灾害

中巴公路穿越的西喀喇昆仑—喜马拉雅地区生存着除极地之外最大的陆地冰川群,是世界上著名的跃动型冰川活动区,发育典型的"冰湖溃决型"冰川。历史上,冰川跃进,堵塞河道(冰川支谷),形成短暂堰塞冰湖,溃坝泄流,形成洪水或泥石流,对中巴公路沿线造成惨重伤亡与财产损失。文献记录表明,1780年以来,大型冰湖溃决事件多起源于印度河上游的新沙勒河谷(Shingshal valley)和希约克河谷上游(Upper Shyok River valley)。近年来,中巴公路沿线水系或冰川河谷,并没有发生流域性规模的冰湖溃决灾害,中小型冰湖溃决事件不是因冰川跃进,更多的是因为升温作用造成的冰舌萎缩涌水、冰湖渗透溃堤,或因冰上湖或冰前湖在冰崩、岩崩等激发因素的直接触发下,形成涌浪翻坝,导致冰湖溃决。本文基于近300年的历史文献,开展了10多年的持续野外调查工作,采用遥感解译、定点观测与案例分析等研究手段,对中巴公路沿线冰湖溃决灾害的河流背景、灾害历史、冰湖的分类、形成与溃决机制等进行时间梳理和汇总分析。本文将为中巴公路地质灾害的研究提供本底认识,可为区域自然灾害研究提供基础性数据支撑。

An integrated land change modeler and distributed hydrological model approach for quantifying future urban runoff dynamics

Climate and land use changes have a significant impact on the runoff generation process in urban environments, and these effects could get worse in the future. The combined contributions of these changes have increased the risk of flooding.Therefore, there is a need for integrated modeling to better understand the runoff variability, especially in small urban catchments. To quantify and separate the effects of land-use changes and climate change on the hydrological response of urban catchments with a distributed hydrological model(Storm Water Management Model, SWMM), this study introduces a new integrated approach based on the Machine Learning based land use change modeler and climate change scenarios under CMIP6.Based on supervised classification and land use change model analysis, accumulated impervious area increase from 22%(in2023) to 33%(in 2060) was observed in the study area. Furthermore, integrating this projected increase in imperviousness with future climate change into SWMM by considering three different scenarios i.e., S1(Climate Change), S2(Combined Land Use and Climate Change), and S3(Land use Change) resulted that climate change could cause an increase in runoff from 13.2% to18.3% in peak runoff and the contribution of land use could range from 9.1% to 18.6%. Similarly, in response to the coupled effects of climate and land-use change, the runoff would likely change from 24.53% to 39.66%. Conclusively, the study showed that despite climate change, intensive urban development by the substitution of impervious surfaces could also have a severe impact on the microclimate and hydrology of small catchments. Lastly, this study could provide a way forward for the future planning and management of water resources in small catchments which could be extended to larger catchments.

Synthesis, structure and magnetic properties of a decanuclear Fe(Ⅲ)/oxo cluster

An iron(Ⅲ) cluster,namely [Fe10(μ3-O)8L8(NO3)6](1),has been synthesized by treatment of Fe(NO3)3·9 H2O with 3,5-dimethyl-l-(hydroxymethyl)-pyrazole(HL) under ambient temperature.The core skeleton of {FeⅢ10) can be regarded as a pear-like cage with eight triangular {FeⅢ3(μ3-O)} units,in which each three FeⅢ centers is held together by one μ3-O2- group with FeⅢ centers as corner-sharing triangle units.Importantly,{FeⅢ10} cluster is not only stable in solid state but also in solution,which is confirmed by powder X-ray diffraction(PXRD) pattern and electrospray ionization mass spectrometry(ESI-MS),respectively.Furthermore,1 shows anti ferromagnetic exchange behavior arising from the interactions between the iron(Ⅲ) centers.