The change and prediction of temperature and precipitation in the Dawen River basin using the statistical downscaling model (SDSM)

In order to explore the climate change in the Dawen River basin,based on the data of six weather stations in the Dawen River basin from 1966 to 2017,Mann Kendall test and wavelet analysis were used to study the temperature and precipitation trends,mutations and cycles in the region.In addition,based on the three scenarios of RCP2.6,RCP4.5,and RCP8.5 under the CanESM2 model,SDSM was used to compare and analyze the future climate change of the Dawen River basin.The results revealed that:the annual mean temperature of the Dawen River basin had increased significantly since 1966 (p<0.01);in different scenarios,the spatial distribution of the projected maximum temperature,minimum temperature and precipitation will hardly change compared with that in history;the temperature and precipitation in the Dawen River basin will generally increase in the future.The rising trend of maximum and minimum temperature under the three scenarios is in the EP相似文献   

统计降尺度方法对黄河上游流域气象要素模拟分析

将CMIP5模式的输出作为降尺度的输入来预估区域性气候的研究较少,本文使用CMIP5中精度较高的Can ESM2模式下的RCP4.5情景(中等温室气体排放)对黄河上游流域未来气象要素进行预估。利用黄河上游流域(上诠站以上)14个气象站点1967-2010年的逐月降水、气温和NCEP再分析资料,选取拟合度、均值相对误差、标准差相对误差作为评价指标,利用逐步回归算法筛选22个预报因子,建立了月资料序列的统计降尺度模型,并将模型应用于CMIP5中Can ESM2模式下RCP4.5情景,产生了未来气候要素的变化情景。结果表明:该模型对降水的模拟效果好于对气温的模拟。     

鄱阳湖流域气候变化及其对入湖径流量的影响

为分析鄱阳湖流域气候变化特征及评估其对流域径流的影响,研究利用1961-2010年间鄱阳湖流域29个气象站和入湖"五河"水文控制站观测数据,分析该时段内流域气候和径流量变化趋势,建立统计模型分析其对流域径流量的影响。研究结果表明:鄱阳湖流域年气温呈显著性(99%置信度检验)波动上升趋势,流域降水总体呈略上升趋势,降水天数呈下降趋势。受气候变化的影响,鄱阳湖流域径流量呈上升趋势。统计模型计算结果表明,径流量与降雨变化呈非线性关系,径流量对降雨变化有着较强的敏感性,相同的气温变化情景下,降水增加比降水减少对径流量的影响更加显著,表明降水变化对径流量有着不同程度和方向的影响作用。气温对径流的影响呈线性,但其影响不明显。未来气候变化情景下,2050年前鄱阳湖流域在高排放A2和RCP8.5情景下呈现明显增长趋势,但其径流量低于其他排放情景。     

金沙江中上游流域未来径流模拟研究

为了探究金沙江中上游流域未来径流变化趋势,为流域防洪规划提供依据,基于SWAT水文模型,选用CMIP5数据集建立未来时段的全球气候模式,从时间和空间尺度解析研究区2022—2050年径流变化趋势。结果表明：流域2022—2050年降水量和平均气温均高于基准期,并且呈现上升趋势,其中流域南部降水量增幅较大,流域北部气温增幅较大。在RCP2.6、RCP4.5、RCP8.5 3种气候情景下,2022—2050年年径流量均呈现增大趋势,变化率分别为5.79×10⁸、5.53×10⁸、2.99×10⁸ m³/a。相较于基准期,未来春季和秋季径流量呈现减少趋势,夏季和冬季径流量呈现增加趋势,冬季径流量增幅达到了10%。流域产流量呈现从西北到东南依次增加的特点,相较于基准期,流域南部产流量均呈现增加趋势。未来径流量呈现增加趋势,冬季径流量增幅较大,可能会发生冬汛等极端水文事件,流域南部受洪水威胁的可能性进一步增大。     

Downscaling Monsoon Rainfall over River Godavari Basin under Different Climate-Change Scenarios

Evaluating the impact of climate change at river basin level has become essential for proper management of the water resources. In the present study, Godavari River basin in India is taken as study area to project the monthly monsoon precipitation using statistical downscaling. The downscaling method used is a regression based downscaling termed as fuzzy clustering with multiple regression. Among the atmospheric variables simulated by global circulation/climate model (GCM) mean sea level pressure, specific humidity and 500 hPa geopotential height are used as predictors. 1^o × 1^o gridded rainfall data over Godavari river basin are collected from India Meteorological Department (IMD). A statistical relationship is established between the predictors and predictand (monsoon rainfall) to project the monsoon rainfall for the future using the Canadian Earth System Model (CanESM2) over IMD grid points under the Representative Concentration Pathways 2.6, 4.5 and 8.5 (RCP 2.6, 4.5, 8.5) scenarios of Fifth Coupled Model Inter-Comparison Project (CMIP 5). Downscaling procedure is applied to all 25 IMD grid points over the basin to find out the spatial distribution of monsoon rainfall for the future scenarios. For 2.6 and 4.5 scenarios results show an increasing trend. For scenario 8.5 rainfall showed a mixed trend with rainfall decreasing in the first thirty years of prediction and then increasing gradually over the next sixty years.     

1961-2005年黄河流域极端气候事件变化趋势

利用黄河流域58个气象站点1961-2005年的逐日平均气温、最高气温、最低气温和逐日降水量数据,采用百分比阈值法定义极端气温和极端强降水事件,计算气象综合干旱指数(CI),并分析了黄河流域极端气候事件的变化趋势及其空间格局.结果表明:黄河流域极端低温和极端高温天数分别呈减少和增加趋势,平均速率分别为-3.8d/10a和1.7d/10a;年极端强降水总量的变化趋势存在着明显的区域差异,河源区增加最显著,而中游的黄土高原中、东部减少最显著;干旱天数呈减少趋势,河源区减幅最大,河套-宁夏平原以及鄂尔多斯高原西北部的减幅最小.     

长江流域气象干旱演变特征及未来变化趋势预估

基于长江流域及周边范围在内的318个气象站点1956—2018年的实测资料和CMIP5全球气候模式在3种RCPs情景下的预估数据,以标准化降水蒸散发指数作为干旱等级的划分指标,对流域历史气象干旱时空演变特征进行了分析,并预估了流域未来不同排放情景下的气象干旱时空变化趋势。结果表明:①近60 a,流域干旱率年际变化较大,平均干旱率为18.21%。从年代变化来看,近20 a干旱影响范围普遍较大;干旱频发地区主要位于岷江流域,干旱次数呈从上游向下游递减的趋势;高强度的干旱多发生于金沙江中下游地区和成都平原地区,平均场次干旱强度也呈从上游向下游递减的趋势;②在RCP2.6、RCP4.5和RCP8.5情景下,2020—2050年长江流域多年平均干旱面积分别为74.1万km²、75.7万km²和126.4万km²;流域上、中、下游干旱频次多年平均值分别为1.1~1.2次/a、1.0~1.1次/a、1.0~1.1次/a。预估时段内上、中、下游干旱频次较历史时段分别增加38.4%~50.7%,33.7%~45.3%和32.6%~49.6%;预估时段内上、中、下游干旱强度多年平均值分别为-1.68,-1.64,-1.60,与历史时段差别不大。研究结果可为相关部门制订科学合理的干旱灾害防范措施和对策提供科学依据。     

Impacts of Climate Change on Water Resources Availability and Agricultural Water Demand in the West Bank

Global climate change is predicted as a result of increased concentrations of greenhouse gasses in the atmosphere. It is predicted that climate change will result in increasing temperature by 2 to 6°C and a possible reduction of precipitation of up to 16% in the Mediterranean basin. In this study, the West Bank is taken as a case study from the Mediterranean basin to evaluate the effects of such climate change on water resources availability and agricultural water demands. Due to the uncertainty in climate change impacts on temperature and precipitation, a number of scenarios for these impacts were assumed within the range of predicted changes. For temperature, three scenarios of 2, 4 and 6°C increase were assumed. For precipitation, two scenarios of no change and 16% precipitation reduction were assumed. Based on these scenarios, monthly evapotranspiration and monthly precipitation excess depths were estimated at seven weather stations distributed over the different climatic and geographical areas of the West Bank. GIS spatial analyses showed that the increase in temperature predicted by climate change could potentially increase agricultural water demands by up to 17% and could also result in reducing annual groundwater recharge by up to 21% of existing values. However, the effects of reduced precipitation resulting from climate change are more enormous as a 16% reduction in precipitation could result in reducing annual groundwater recharge in the West Bank by about 30% of existing value. When this effect is combined with a 6°C increase in temperature, the reduction in groundwater recharge could reach 50%.     

GCMs降尺度及其在讨赖河上游径流预报中的应用

在气候变化和人类活动影响下,内陆河流域出山径流变异程度提升,研究径流预测及其对气候变化响应具有理论和实践的双重意义。以讨赖河流域上游为研究区,采用Delta降尺度及权重集成方法对14种GCMs在3种RCP情景下的气温和降水进行优化,预测分析了该区未来径流变化和水资源供需平衡。结果表明:由气候-生态联合驱动的径流预测模式在讨赖河流域适用性良好,气温对出山径流总体呈负减效应,降水和NDVI表现为正增效应。未来气温和降水呈增加趋势,增温主要发生在河谷地带,降水增加在分水岭周边更为显著。流域出山径流总体增加,不同子区径流变幅从小到大依次为OL06＜OL04＜OL05＜OL01＜OL03＜OL02。尽管未来出山径流有所增加,但从水资源满足度来看,平、枯水年讨赖河流域仍存在水资源短缺问题。     

“一带一路”区域未来RCPs情景降水变化分析

以“一带一路”地区作为研究区域,利用分位数映射法的4种传递函数订正全球气候模式(HadGEM2-ES)不同RCPs(Representative Concentration Pathways,温室气体浓度轨迹)情景的月降水量,以获得更具可靠性的未来降水变化的预测结果;在此基础上分析未来各地区不同RCPs情景年降水量变化趋势以及差异情况。利用均方根误差RMSE和降水偏差diff分析比较分位数映射法的订正效果,结果显示线性参数化方案PTFl法建立的传递函数综合订正效果最佳;同时也发现未订正的HadHEM2-ES在东亚和俄罗斯等地区存在明显的降水增加趋势高估。订正后的未来“一带一路”降水变化显示:①东亚、东南亚和俄罗斯地区的降水量在4个情景多为增加趋势,北非、西亚地区在4个情景多为减少趋势。②未来平均年降水量总体呈增加趋势;区域平均值中,EA(东亚)和Rus(俄罗斯)增加趋势明显,WA(西亚)和NAfr(北非)则是减少趋势。各地区降水突变情况存在明显的情景差异,RCP2.6情景突变情况最少,其他3种情景在不同地区都有不同的表现。分析结果为今后的政策制定或工程建设提供有效的参考依据。     

新安江流域气候变化及径流响应研究

针对新安江流域新安江水库控制区域,构建新安江月水文模型,利用1979-2005年实测水文资料对模型进行率定和验证,并以CMIP5大气环流模式输出驱动水文模型,生成2006-2099年该流域在RCP2.6、RCP4.5和RCP8.5情景下的逐月径流过程。在此基础上,研究气候变化背景下流域气温、降雨、蒸发和径流的变化趋势,并对其不确定性进行分析。结果表明:2006-2099年该流域年均气温与年蒸发深度均呈上升趋势,且对于辐射强度变化较敏感,呈显著正相关关系。流域年降雨量与径流深呈波动上升趋势,对于辐射强度变化敏感性并不显著。年径流深在丰水年和平水年相对基准期有所减少,而在枯水年和特枯水年则呈增加趋势。月径流深在秋、冬季呈上升趋势,在春、夏季则呈下降趋势。     

ＲCPs 情景下贵州省干旱趋势分析

为探究贵州省未来干旱变化趋势,基于 CMIP5 全球气候模式预估的降水月值数据,利用标准化降水指数(SPI)分析了 2016—2050 年 ＲCPs 情景下贵州省干旱趋势。结果表明: 2016—2050 年间ＲCP2. 6、ＲCP4. 5 和 ＲCP8. 5 情景下贵州省 SPI 指数均呈现增加趋势。除特旱外,ＲCP8. 5 情景下轻旱、中旱、重旱发生频次高于 ＲCP2. 6 和 ＲCP4. 5 情景。2016—2030 年各情景下各干旱等级发生频次较高。不同情景下各干旱等级的干旱频率空间异质性突出。各情景下贵州省干旱站次比和干旱强度均呈现下降趋势,发生全域性干旱年份较多,发生区域性干旱和局域性干旱年份较少。发生轻度干旱强度年份较多,发生中度干旱强度和重度干旱强度年份较少。ＲCPs 情景下贵州省降水增加导致干旱风险降低。研究结果可为干旱监测和农业生产提供参考依据。     

基于SDSM的疏勒河流域气候变化统计降尺度研究

疏勒河流域属于气候变化敏感区和生态脆弱区,开展该流域未来气候变化研究,对于水资源合理利用及生态环境保护具有重要意义。为预估该流域的未来气候变化,采用SDSM(statistical downscaling model)模型,根据6个地面气象站41年(1961—2001年)的观测数据、NCEP数据和Had CM3模式模拟数据开展未来气温和降水降尺度研究。结果表明:SDSM对气温的月值模拟精度较高,各站月平均气温纳什效率系数均在0.98以上;SDSM对降水的月值模拟值较实测值整体偏高,模拟效果最好的托勒站月累计降水的纳什效率系数达到0.6。SDSM能较好地模拟气温的年际变化,模拟的年际变化趋势与实测值相差不大;但SDSM对降水的年际变化模拟较差,一些站点的变化趋势方向相反,趋势模拟最好的站点为托勒站和瓜州站。根据SDSM预估结果,与1961—2001年平均值相比,2020—2039年各站点的平均气温均有所升高,A2情景下升幅为(0.8~1.9)℃,B2情景下升幅为(1~2)℃;降水在A2和B2情景下差别不大,其中托勒站减少约54 mm,马鬃山站增加6 mm。研究发现,除托勒站外,疏勒河流域与预报变量相关性最高的预报因子并不在站点所在网格,而是其东侧网格,其原因有待进一步研究。     

Performance Indexes Analysis of the Reservoir-Hydropower Plant System Affected by Climate Change

Assessing the effects of climate change phenomenon on the natural resources, especially available water resources, considering the existing constraints and planning to reduce its adverse effects, requires continuous monitoring and quantification of the adverse effects, so that policymakers can analyze the performance of any system in different conditions clearly and explicitly. The most important objectives of the present research including: (1) calculating the sustainability index for each demand node based on the characteristics of its water supply individually and also calculating the sustainability index of the whole water supply system, (2) investigation the compatible of changes trend among various reservoir performance indexes and (3) evaluation the changes in performance reservoir indexes in the future time period compared to the baseline tie period under three Concentration Pathway (RCP) RCP2.6, RCP4.5 and RCP8.5 scenarios for all water demand nodes and the entire water supply system. To this end, first, climatic parameters data affecting on the water resources such as temperature and precipitation were gathered in the baseline period (1977–2001) and the climatic scenarios were generated for the future period (2016–2040) using the Fifth Assessment Report (AR5) of the International Panel on Climate Change (IPCC). Then, the irrigation demand changes of the agricultural products with the Cropwat model and the value of inflow to the reservoir with the Artificial Neural Network (ANN) model were calculated under the climate change effects. In the next step, the climate change effects on the water supply and demand were simulated using Water Evaluation and Planning model (WEAP), and its results were extracted so as the water management indexes. The results show that the temperature will increase in the future period under all three RCP scenarios (RCP2.6, RCP4.5 and RCP8.5) compared to the baseline period, while precipitation will decrease under the RCP2.6 scenario but will increases under RCP4.5 and RCP8.5 scenarios. Under the trend of changing in temperature and rainfall, the irrigation demand in the agricultural sector in all scenarios will increase compared to the baseline period. However, the inflow of reservoir will decrease under the RCP2.6 and RCP4.5 scenarios and will increases under RCP8.5 scenario. Evaluation of WEAP modeling results shows that the sustainability index of the entire Marun water-energy system will decrease in the future period compared to the baseline period under the RCP2.6, RCP4.5 and RCP8.5 scenarios by 13, 10 and 8%, respectively. The decrease in the system sustainability index shows that in the absence of early planning, the Marun water-energy supply system will face several challenges for meeting the increasing demand of water in different consumer sectors in the coming years.

     

布哈河流域水资源的气候演变特征

布哈河是青海湖最重要的径流补给河流,其流域水资源气候演变分析对于青海湖生态安全有重要意义。通过天骏、刚察、茶卡气象站长系列气温、降水数据分析布哈河流域气候变化特征。结果表明,近50年来,流域内气温均显著升高,海拔越高升温越明显,冬季升温较其它季节明显。采用Mann-Kendall趋势分析法和累计距平曲线对各时段的升温趋势变化进行了分析,升温自1986年开始至1997年有一个10年左右的波动期,随后在1997出现显著的突变过程,在与青藏高原整体趋势一致的基础上表现出区域自身的增温特点。降水呈增加趋势,但不如温度明显。海拔越高降水增加越明显,夏季降水增加较其它季节明显。根据气温和可利用降水变化特征,流域20世纪80年代开始进入增温增湿期,在20世纪90年代进入相对暖干期,21世纪前10年复转为暖湿期。     

Analysis and prediction of reference evapotranspiration with climate change in Xiangjiang River Basin,China

Reference evapotranspiration(ET_0) is often used to estimate actual evapotranspiration in water balance studies. In this study, the present and future spatial distributions and temporal trends of ET_0 in the Xiangjiang River Basin(XJRB) in China were analyzed. ET_0 during the period from1961 to 2010 was calculated with historical meteorological data using the FAO Penman-Monteith(FAO P-M) method, while ET_0 during the period from 2011 to 2100 was downscaled from the Coupled Model Intercomparison Project Phase 5(CMIP5) outputs under two emission scenarios, representative concentration pathway 4.5 and representative concentration pathway 8.5(RCP45 and RCP85), using the statistical downscaling model(SDSM). The spatial distribution and temporal trend of ET_0 were interpreted with the inverse distance weighted(IDW)method and Mann-Kendall test method, respectively. Results show that:(1) the mean annual ET_0 of the XJRB is 1 006.3 mm during the period from 1961 to 2010, and the lowest and highest values are found in the northeast and northwest parts due to the high latitude and spatial distribution of climatic factors, respectively;(2) the SDSM performs well in simulating the present ET_0 and can be used to predict the future ET_0 in the XJRB; and(3) CMIP5 predicts upward trends in annual ET_0 under the RCP45 and RCP85 scenarios during the period from 2011 to 2100.Compared with the reference period(1961e1990), ET_0 increases by 9.8%, 12.6%, and 15.6% under the RCP45 scenario and 10.2%, 19.1%, and27.3% under the RCP85 scenario during the periods from 2011 to 2040, from 2041 to 2070, and from 2071 to 2100, respectively. The predicted increasing ET_0 under the RCP85 scenario is greater than that under the RCP45 scenario during the period from 2011 to 2100.     

塔里木河流域降水量的非线性时空变化对比研究及预测

基于塔里木河流域25个气象站1961-2007的实测降水量数据,本文利用Mann-Kendall、R/S分析以及小波分析和周期性叠加趋势模型对塔里木河流域降水量的非线性时空变化特征进行分析,并对未来降水量的变化做出预测。结果表明:1961-2007年之间塔里木河流域降水量整体呈增加趋势,位于塔里木河干流北侧气象站增加趋势要明显强于南侧,其中阿克苏河、迪那河、库车-渭干河和塔里木河干流流域呈极显著增加趋势;在塔里木河干流及阿克苏河源流区出现了增加率的高值中心,最大值在阿合奇,开都-孔雀河的源流区为降水量减少的高值中心,最大减少率在巴音布鲁克;塔里木河干流及子流域的Hurst指数均大于0.5,表明塔里木河流域降水量将保持较鲜明的持续性;相比较1998-2007年,迪那河流域和库车-渭干河流域降水量在2015-2020年的增加值最大。     

太湖流域气候变化检测与未来气候变化情景预估

基于1954—2006年太湖流域6个气象站点的降水、气温资料,探讨了1954年以来太湖流域的气候变化问题,并同时应用统计降尺度模型SDSM和动力降尺度模型PRECIS,对太湖流域的日降水量和日最高、最低气温进行降尺度处理,建立未来2021—2050年的气候变化情景。结果表明:20世纪90年代以来,太湖流域发生了突变式增温,冬、春季节尤为显著;太湖流域降水变化相对较复杂,Mann Kendall法检测到太湖流域年降水量呈振荡性周期变化,并在1980年和2003年发生突变,而Pettitt方法没有检测出太湖流域年降水量的突变。两种降尺度方法模拟的未来时期日最高、最低气温季节和年的变化情景增幅总体上基本一致,均呈显著增加趋势,与Mann Kendall趋势分析结果一致,高排放情景A2下模拟生成的情景增温幅度较低排放情景B2大,最高气温增加幅度比最低气温明显。降水变化情景差异较大,SDSM模拟的未来时期降水并无明显变化趋势,而PRECIS模拟结果与趋势检验结果较为一致,即未来降水增加趋势明显,增幅较大,总体上全流域年降水量呈增加趋势,并且在未来一段时间内仍将持续增加。     

气候变化对嘉陵江流域降水变化影响分析

以长江上游支流嘉陵江为研究对象。利用嘉陵江流域的11个国家气象站1961年-2001年的实测降水数据和NCEP再分析数据,建立了嘉陵江流域降水的统计降尺度模型。在A2和B2排放情景下应用HadCM3的输出数据,预测嘉陵江流域未来三个时期（2010年-2039年、2040年-2069年、2070年-2099年）降水变化情况。分析结果表明相对于基准期的模拟降水量,在HadCM3的A2和B2排放情景下．模拟得到嘉陵江流域大部分区域的降水量有明显上升趋势。     

长江上游保护区径流变化特征及其对气候因子响应的区域差异性研究

分析河川径流的演化规律和动因,对于变化环境下的水生态环境和水资源适应性规划管理十分重要。以长江上游保护区屏山、朱沱和赤水站的1956—1990年的近自然状态径流为研究对象,分别利用小波分析方法、非参数Mann-Kendall趋势分析方法和弹性系数方法,探究了径流变化的多时间尺度演变特性、变化趋势和径流变化对气候因子的响应状况。结果表明:3个研究站点的年径流周期性变化存在相似性,都有着10~14 a的丰枯震荡周期。各站点的径流在年和季节尺度上呈现增加的趋势,但在月尺度上,屏山和朱沱站情况相似,在8月份径流存在明显的下降趋势,赤水站径流在3,4月份有显著增加。3个站点的径流都对降雨的敏感度较高,但是各站点年径流对气候因子的响应也存在区域差异性,流经区域大多位于高山峡谷的屏山站和赤水站,其年径流对降雨的弹性系数要大于朱沱站,而位于四川盆地区域的朱沱站的年径流对蒸发的弹性系数要稍微大于屏山和赤水站。