青藏高原多年冻土活动层厚度对气候变化的响应

活动层厚度变化将会对多年冻土区生态系统、地气间能水平衡和碳循环等产生重要影响。利用Stefan公式模拟了1981-2010年青藏高原多年冻土区活动层厚度的分布和空间变化特征。结果表明：多年冻土区活动层厚度平均为2.39 m,活动层厚度在羌塘盆地最小,在多年冻土区边缘、祁连山、西昆仑山、念青唐古拉山活动层厚度较大。在气候变化条件下,青藏高原多年冻土区活动层厚度呈整体增大趋势,在1981-2010年,活动层厚度的变化量为-1.54~2.24 m,变化率为-5.90~10.13 cm·a^-1,平均每年变化1.29 cm。活动层增厚趋势与年平均气温增大的趋势基本一致,这说明气候变化对活动层厚度变化有很大的影响。     

Assessing the response of runoff to climate change and human activities for a typical basin in the Northern Taihang Mountain,China

Climate change and human activities are the two main factors on runoff change. Quantifying the contribution of climate change and human activities on runoff change is important for water resources planning and management. In this study, the variation trend and abrupt change point of hydro-meteorological factors during 1960–2012 were detected by using the Mann–Kendall test and Pettitt change-point statistics. Then the runoff was simulated by SWAT model. The contribution of climate change and human activities on runoff change was calculated based on the SWAT model and the elasticity coefficient method. The results showed that in contrast to the increasing trend for annual temperature, the significant decreasing trends were detected for annual runoff and precipitation, with an abrupt change point in 1982. The simulated results of SWAT had good consistency with observed ones, and the values of \(R^{2}\) and \(E_{NS}\) all exceeded 0.75. The two methods used for assessing the contribution of climate change and human activities on runoff reduction yielded consistent results. The contribution of climate change (precipitation reduction and temperature rise) was \({\sim }37.5\%\), while the contribution of human activities (the increase of economic forest and built-up land, hydrologic projects) was \({\sim }62.5\%\).     

青藏高原中部新生代伦坡拉盆地沉降史分析

新生代伦坡拉盆地位于青藏高原中部,拉萨地体与羌塘地体间班公湖-怒江缝合带之上.伦坡拉盆地及缝合带上其他陆相盆地的形成反映了班怒带缝合之后的再活化过程.盆地内部主要沉积了始新世-中新世牛堡组与丁青湖组两套地层,虽然后期的风化剥蚀和地表第四纪覆盖对获取野外露头资料造成了一定影响,但20世纪50年代以来大规模的钻井勘探为研究区域大地构造和沉积盆地演化提供了重要依据.为重建伦坡拉盆地的沉降史,本文对盆地中11条钻井剖面和1条实测剖面进行了回剥分析.沉降曲线显示盆地经历了两个明显不同的沉降阶段和一个缓慢抬升阶段.初始的快速沉降开始于始新世,在区域伸展作用下上地壳破裂形成半地堑型盆地,并开始在滨浅湖环境中沉积牛堡组地层.这一过程中伴有左行走滑.渐新世早期,受构造活动之后热量传导的影响,前期快速沉降被缓慢热沉降取代,沉降中心向北东方向迁移,并在半深湖-深湖环境下沉积丁青湖组地层.与此同时印度板块不断向北俯冲,在挤压作用下热沉降逐渐减弱并提前结束.中新世波尔多阶基底开始构造抬升,盆地不断发生挤压变形,并最终形成了现今的构造格局.     

Gender and climate change linkages in the semi-arid region of Ghana

GeoJournal - Climate change is projected to have a serious impact on all sectors of the world. The agriculture sector is one of the most vulnerable sectors with implications for smallholder farmers...     

海河流域河川径流对气候变化的响应机理

利用可变下渗容量(Variable Infiltration Capacity,VIC)模型,在海河流域选取了6个典型流域来率定VIC模型的参数。通过模型参数移植技术,建立了全流域的径流模拟平台。根据假定的气候变化情景,分析了海河流域河川径流对气候变化的响应机理。结果表明:在年平均气温升高2℃时,海河流域的径流量将减少6.5%;当年降水量增加或者减少10%时,海河流域的径流量将分别增加26%和减少23%;当汛期降水占年降水量的比例分别增加或者减少10%时,全流域的径流量将会增加12%或者减少7%;在空间上,在年平均气温升高和年降水量变化的情景下,海河流域西北部的河川径流比东南部更敏感;在降水年内分配变化的情景下,海河流域东南部的河川径流比西北部更敏感。总体上,年降水量越大,径流量对降水量的敏感性越小,对平均气温的敏感性也越小,而对降水年内分配的敏感性越大。     

湿润亚热带典型白云岩流域的岩溶无机碳汇强度

岩溶作用积极参与全球碳循环过程,进一步弄清岩溶碳汇机制对于精确评估碳循环过程意义重大。中国碳酸盐岩分布面积广大,尤以西南地区最为广泛与集中,虽然本区已开展了较多以石灰岩为主流域的岩溶碳汇研究,但是与白云岩流域相关的研究较为薄弱,这不利于精确评价中国岩溶碳汇潜力和服务于国家碳中和战略。为此,本文以中国西南岩溶区内具代表性的贵州施秉黄洲河白云岩流域作为研究区,对湿润亚热带典型白云岩小流域的水-岩-气相互作用及其无机岩溶碳汇进行了为期1年(2018年5月至2019年5月)的水文水化学自动监测研究。获得了黄洲河白云岩流域的降雨量、流量、水温、电导率、pH值等高时间分辨率的连续监测数据,并采用化学热力学模型计算了方解石与白云石饱和指数及河水中CO₂分压等水化学指标。结果显示:(1)该白云岩流域属典型的山区雨源型河流,洪水流量过程虽然呈现显著的暴涨暴落特征,但是流域出口河水的化学动态仍受水化学稳态行为的控制;(2)流域上游高原面上浅切割地表河两侧发育溶隙型含水介质,中下游排水系统为地表河,由于地表河水中CO₂的释放,使该流域出口河水的方解石饱和指数较高,并伴有河床钙华沉积;(3)采用白云石开放系统化学热力学模型,结合不同土地利用类型的土壤CO₂数据,计算出泄流于地表河的岩溶地下水 {\mathrm{HCO}}_3^{-}浓度为5.1 mmol/L,该值要高于黄洲河出口河水 {\mathrm{HCO}}_3^{-}平均浓度16%,表明该岩溶流域内的地表河因受紊流脱气和水生生物光合作用的影响,水中的溶解无机碳有所降低;(4)由水化学-径流法准确计算了该白云岩流域的岩溶碳汇通量(以CO₂计),为36.43 t/(km²·a),该值并未显著高于中国南方其他碳酸盐岩流域的岩溶碳汇通量,表明白云岩流域覆被中CO₂浓度仍与流域径流量呈反比关系,这两个主控因子的共同作用,使湿润亚热带岩溶流域的岩溶碳汇通量不至于发生较大变化。     

Hydrological impact of forest fires and climate change in a Mediterranean basin

Forest fire can modify and accelerate the hydrological response of Mediterranean basins submitted to intense rainfall: during the years following a fire, the effects on the hydrological response may be similar to those produced by the growth of impervious areas. Moreover, climate change and global warming in Mediterranean areas can imply consequences on both flash flood and fire hazards, by amplifying these phenomena. Based on historical events and post-fire experience, a methodology to interpret the impacts of forest fire in terms of rainfall-runoff model parameters has been proposed. It allows to estimate the consequences of forest fire at the watershed scale depending on the considered burned area. In a second stage, the combined effect of forest fire and climate change has been analysed to map the future risk of forest fire and their consequence on flood occurrence. This study has been conducted on the Llobregat river basin (Spain), a catchment of approximately 5,000 km² frequently affected by flash floods and forest fires. The results show that forest fire can modify the hydrological response at the watershed scale when the burned area is significant. Moreover, it has been shown that climate change may increase the occurrence of both hazards, and hence, more frequent severe flash floods may appear.     

青藏高原若尔盖生态区水资源对气候变化的响应

利用1980-2012年若尔盖水文站径流量资料、若尔盖及周边20个站同期气象观测数据,通过分析径流量演变规律及与气候因子的关系,研究了若尔盖生态区水资源对气候变化的响应.结果显示：近30 a该区域地表水资源整体呈波动下降趋势,气候倾向率为1.4×10⁸ m³·（10a）^-1;径流量的年际分布较均匀,年内分配呈双峰型,主要集中在6-9月,同期径流量集中度、集中期及丰枯率均呈现下降趋势,峰型度呈上升趋势,这与全球气候变暖及降水量减少相关.降水量是影响该流域径流量的最主要因子,夏季降水量很大程度决定着径流量的丰枯,而秋季径流量对降水量的响应最为敏感.气温的升高导致高山冰雪消融量的增大,进而使非汛期径流量增加;同时,流域蒸发量的加大,增加了地表水资源的消耗.     

祁连山老虎沟流域强消融期径流对气候变化的响应

为定量研究老虎沟流域径流对气候变化的响应,利用老虎沟流域1959年和2014年强消融期（7月）的气象、径流数据,分析了强消融期气温、降水、蒸发、冰川消融量、径流（流域的径流深）等的变化,进而探讨了老虎沟流域强消融期气温分布和降水形态、流域蒸发和冰川消融对径流的影响。结果表明：老虎沟流域2014年强消融期径流比1959年多159 mm,增加了49.67%。2014年7月平均气温较1959年升高0.38℃,最低气温升高1.34℃。1959年和2014年7月降水量相差较小;老虎沟流域强消融期日降水和日径流之间呈负相关,蒸发量的变化较小,流域内祁连山站的混合态降水比例减少23.01%,导致降水转化为径流的比例增大;起决定性作用的是正积温, 2014年7月较1959年的正积温高11.71℃·d,主要由于2~4℃的气温日数增多导致正积温增加,从而加剧冰川消融对径流的补给。     

吐鲁番盆地第四纪气候变迁及其对砂岩型铀成矿作用的意义

本从吐鲁番盆地第四系典型剖面的岩性岩相和孢粉组合特征入手，分析了这些特征所反映的气候类型和性质。结果表明，吐鲁番盆地第四纪以来以干凉为主，间有温和湿润的气候，比较有利于砂岩型铀矿化的形成。     

Spatial variability of soil moisture at typical alpine meadow and steppe sites in the Qinghai-Tibetan Plateau permafrost region

Permafrost degradation has the potential to significantly change soil moisture. The objective of this study was to assess the variability of soil moisture in a permafrost region using geostatistical techniques. The experiment was conducted in August 2008 in alpine steppe and meadow located in the Qinghai-Tibetan Plateau permafrost region. Four soil depths (0–10, 10–20, 20–30 and 30–40 cm) were analyzed using frequency domain reflectometry, and sampling made of 80 points in a 10 m × 10 m grid were sampled. Soil moisture was analyzed using classical statistics to appropriately describe central tendency and dispersion, and then using geostatistics to describe spatial variability. Classical statistical method indicated that soil moisture in the permafrost region had a normal distribution pattern. Mean surface soil moisture in alpine meadow was higher than that in alpine steppe. The semivariograms showed that soil moisture variability in alpine cold steppe was larger than that in alpine meadow, which decreased with depths. Nugget values in alpine steppe were low (0.1–4.5), in contrast to alpine cold meadow. Soil moisture in alpine steppe had highly structured spatial variability with more than 93.4% spatial heterogeneity, and the range decreased with depth. Soil moisture content in alpine cold meadow had a moderate spatial dependence with a range of 51.3–169.2 m, increasing with depth.     

气候变化对黄河流域生态径流影响预估

人类活动和气候变化严重改变了黄河水文情势和生态径流,分析未来气候变化对河流生态的影响对流域水资源管理和长期规划意义重大。本文对第六次国际耦合模式比较计划（CMIP6）的13个全球气候模式数据进行偏差订正,驱动水文模型进行径流模拟,应用流量历时曲线方法分析SSP1-2.6、SSP2-4.5、SSP5-8.5情景下2026年至21世纪末年、季节尺度的花园口生态径流变化。结果表明:订正能明显降低降水、气温模拟偏差;人类活动严重影响了1986-2010年花园口生态径流;2026-2100年年均气温和年降水量增加趋势显著,低排放情景增速慢,高排放情景增速快;气候变化可在一定程度上缓解水库调控、水土保持等人类活动对生态径流的负面影响,SSP5-8.5情景缓解程度最高,冬季缓解程度最高,夏、秋季最低。     

Analysis of extreme precipitation and its variability under climate change in a river basin

Natural Hazards - This study investigated the variation of extreme precipitation on a catchment under climate change. Extreme value analysis using generalized extreme value distribution was used to...     

土地利用变化对海河流域典型区域的径流影响

为研究海河流域径流对土地利用变化的响应,以阜平流域、匡门口流域和界河铺流域为研究区,利用1970—2011年的水文气象资料,分析了不同土地利用的时空转移特征,然后结合SWAT(Soil and Water Assessment Tool)模型,设置4种土地利用情景,评价了土地利用变化对径流的影响。结果表明:模型能够较好地模拟全年及汛期月流量过程;多年径流量呈下降趋势,20世纪80年代到90年代中期呈波动性变化;不同的土地利用类型在时空上的转化呈现可逆性,主要是林地增加,草地减少,耕地略有增加;林地的增加和草地的减少会降低汛期径流量以及最大月径流量;汛期径流系数随着林地面积的增加而减小。合理地规划土地利用格局,对控制流域水文事件具有重要意义。     

黄河中游水文变化趋势及其对气候变化的响应

黄河中游水资源匮乏,分析水文要素变化趋势对实现水资源的可持续开发利用具有重要意义。根据流域地貌特征及水文站控制情况,将黄河中游划分为3个区间,分别为:河-龙区间、龙-三区间和三-花区间,采用Mann-Kendall秩次相关检验法与线性回归方法,分析检验了各区间年径流量的历史变化趋势。采用设定情景与水文模拟相结合的途径,评估了不同区间河川径流量对气候变化的响应。根据1950-2005年资料分析,结果表明:黄河中游干流控制站实测径流量与区间径流量均具有显著的减少趋势。若气温升高1℃,年径流量将减少3.7%~6.6%;河川径流对降水变化更为敏感,若降水减少10%,河川径流量将减少17%~22%;近些年黄河中游气温升高和降水减少是河川径流减少的重要原因之一。     

青藏高原气候变化若干前沿科学问题

在全球变化的背景下,青藏高原冰冻圈和大气圈正在发生快速变化,对"亚洲水塔"和"第三极"的生态环境带来深刻影响.研究并梳理了近年来青藏高原气候变化的若干前沿科学问题的研究进展,如高原极端气候事件变化及其与大气环流的关系;高原变暖放大效应及海拔依赖型变暖的物理机制;再分析资料在高原气候变化应用的适用性;气候模式在高原资料稀...     

The response of the environment of the Angara-Lena Plateau to global climate change in the Holocene

The paper is focused on the regularities and character of the response of the regional landscapes of the Angara-Lena Plateau to variations in the global climate system during the Holocene. They were revealed by integrated studies of four peat bogs of the plateau—an important area for the understanding of the environmental dynamics in the entire Baikal region. Age models for the records obtained were provided by 16 radiocarbon dates. A spatiotemporal correlation of spore-pollen indices with the trend of 5¹⁸O records from the global stratotypes was used to find out the possible causes of changes in the landscapes and climate of the Angara-Lena Plateau in the context of past changes in the global climate system. The plateau environment showed a dramatically varying response to global climate variations in the Middle-Late Holocene. Moreover, the observed intervals of reorganization in the regional environment took place in a quasi-millennial regime, in accordance with global climate rearrangement. However, not all the studied regions of the Angara-Lena Plateau exhibited a synchronous or analogous response to global environment change. This emphasizes the complicated character of regional climate manifestations in the Holocene and necessitates the use of paleogeographical data from a wider range of territories.