标准化径流指数在阿克苏河水文干旱特征识别中的应用

阿克苏河位于丝绸之路经济带重要通道,是典型的中亚跨境河流,阿克苏丰富的水资源成为沿岸各国争夺的焦点。针对阿克苏河未来水资源评估和管理的迫切需要,以阿克苏河干流月径流为数据基础,结合径流距平百分比,采用标准化径流指数(Standardized Runoff Index,SRI)辨识阿克苏河水文干旱事件,并验证了水文干旱识别的合理性。结果表明:SRI丰枯等级划分临界值在阿克苏河能够有效地识别水文干旱事件及其干旱等级,SRI趋势分析发现未来阿克苏河春、夏季洪水和冬旱现象的可能性在逐渐增大,水资源季节差异将越来越明显,这将是未来水资源合理利用和管理的一个新挑战。     

Comparison of Meteorological,Hydrological and Agricultural Drought Responses to Climate Change and Uncertainty Assessment

A comparison study of meteorological, hydrological and agricultural drought responses to climate change resulting from different General Circulation Models (GCMs), emission scenarios and hydrological models is presented. Drought variations from 1961–2000 to 2061–2100 in Huai River basin above Bengbu station in China are investigated. Meteorological drought is recognized by the Standardized Precipitation Index (SPI) while hydrological drought and agricultural drought are indexed with a similar standardized procedure by the Standardized Runoff Index (SRI) and Standardized Soil Water Index (SSWI). The results generally approve that hydrological and agricultural drought could still pose greater threats to local water resources management in the future, even with a more steady background to meteorological drought. However, the various drought responses to climate change indicate that uncertainty arises in the propagation of drought from meteorological to hydrological and agricultural systems with respect to alternative climates. The uncertainty in hydrological model structure, as well as the uncertainties in GCM and emission scenario, are aggregated to the results and lead to much wider variations in hydrological and agricultural drought characteristics. Our results also reveal that the selection of hydrological models can induce fundamental differences in drought simulations, and the role of hydrological model uncertainty may become dominating among the three uncertainty sources while recognizing frequency of extreme drought and maximum drought duration.     

基于Copula函数的新型综合干旱指数构建与应用

干旱指数是研究干旱的重要工具,构建综合干旱指数是目前干旱监测、风险评估的前沿和趋势。本文基于阿基米德Copula函数,联合降雨(气象)、径流(水文)两种要素,构建了一种能够综合表征气象干旱和水文干旱的新型综合干旱指数MSDI_p,并用其表征渭河流域的干旱演变特征,且进一步对其背后的驱动力进行了探究。结果表明:(1)MSDI_p指数既能像标准化降水指数(SPI)一样敏锐地捕捉干旱的发生,也能像标准化径流指数(SRI)一样很好地刻画干旱的持续时间和结束,同时具备气象和水文两种干旱指数表征不同类型干旱的优势,能综合表征干旱演变特征;(2)受气候变化和人类活动影响,渭河流域过去50余年综合干旱呈显著增强趋势;(3)渭河流域综合干旱指数序列存在变异点(1994年),且未来流域干旱情势有加剧趋势;(4)太阳黑子和大气环流异常因子等对渭河流域综合干旱的发生有较大影响,其中太阳黑子活动的影响最强。且除直接影响外,太阳黑子还能通过影响大气环流异常因子进而对综合干旱的发生造成间接影响。     

A New Non-stationary Hydrological Drought Index Encompassing Climate Indices and Modified Reservoir Index as Covariates

Due to accelerating climate variability and intensified anthropogenic activities, the hypothesis of stationarity of data series is no longer applicable, questioning the reliability of the traditional drought index. Thus, it is critical to develop a non-stationary hydrological drought index that takes into account the joint impacts of climate and anthropogenic changes in a drought assessment framework. In this study, using the Generalized Additive Model for Location, Scale and Shape (GAMLSS), a new Non-stationary Standardized Runoff Index (NSRI) was developed combining climate indices (CI) and modified reservoir index (MRI) as explanatory variables. This novel index was applied to the hydrological drought assessment of the Hanjiang River basin (HRB) in China, and its reliability was assessed by comparing with the traditional Standardized Runoff Index (SRI). Results indicated that the optimal non-stationary model with CI and MRI as covariates performed better than did other models. Furthermore, NSRI was more robust in identifying extreme drought events and was more effective in the study region than the conventional SRI. In addition, based on the method of Breaks for Additive Seasonal and Trend (BFAST), it was found that there were two change points in 1981 and 2003 for the NSRI series at four hydrological stations in the HRB, which indicated that hydrological drought in the basin had a prominent non-stationary behavior. Our findings may provide significant information for regional drought assessment and water resources management from a changing environment perspective.

     

人类活动影响的辽宁省大凌河流域水文干旱演变特征

为了揭示人类活动干扰对不同时空尺度水文干旱的影响,本文以辽西北大凌河流域为例,利用SWAT(Soil and Water Assessment Tool)模型重建天然状态下的历史水文序列,基于多时间尺度的标准化径流指数(SSI),对比评估天然状态和人类活动影响下的流域水文干旱演变特征.结果表明,人类活动干扰是流域径流序...     

变化环境下时变标准化径流指数的构建与应用

变化环境下,干旱指数可能表现出非一致性特征。本文假设径流序列为二阶非平稳序列,建立以时间为协变量的时变矩GAMLSS模型,该模型采用非一致性Gamma分布拟合实测径流序列,并基于该模型计算出的时变标准化径流指数SRIt,与传统指数SRI进行对比分析,以验证其合理性与必要性。结果表明:基于时变矩模型的时变标准化径流指数SRIt更适应于潘家口水库流域变化环境下水文干旱的评价。时变标准化径流指数SRIt的值整体上比基于一致性模型的指数SRI偏小,即所表示的干旱程度更加严重,主要是因为时变矩GAMLSS模型能够反映出变化环境下径流序列的变化趋势,该趋势是影响径流的一系列因素共同导致的,如气候变化,人类活动等。而在受这些因素的影响下,潘家口水库流域的水文干旱事件频率增加,严重程度增强。     

不同季节气象干旱向水文干旱的传播及其动态变化

研究变化环境下气象干旱向水文干旱的传播与影响机制,有利于揭示水文干旱的形成过程与机理,从而建立基于气象干旱的水文干旱预警.为揭示不同季节气象干旱向水文干旱的传播动态变化及其驱动因素,本研究以无定河、窟野河和沁河流域为研究区域,采用标准化降水指数(SPI)和标准化径流指数(SRI)分别表征气象干旱和水文干旱,分析气象、水...     

Hydrological Drought Class Transition Using SPI and SRI Time Series by Loglinear Regression

Loglinear models for three-dimensional contingency tables was used with data from 21 rainfall stations and 7 hydrometric stations in the Luanhe river basin, northeast China, for short term prediction of drought severity class. Loglinear models were fitted to drought class transitions derived from standardized precipitation index (SPI) and standardized runoff index (SRI) time series to find which series was more suitable for hydrological drought class prediction 1 and 2 months ahead, respectively. Expected frequencies for two consecutive transitions between drought classes were first calculated, and based on this the predicted drought classes 1 and 2 months ahead were obtained. The results showed that despite the contingency tables of drought class transitions presented the maintenance of the precedent drought class, results of three-dimensional loglinear modeling presented good results when comparing predicted and observed drought classes. Only for a few cases predictions did not fully match the observed drought class, mainly for 2-month lead and when the SRI values are near the limit of the severity class predicted by SRI time series. Based on the correlation analysis of SPI and SRI, we presented the well-known method of hydrological drought class prediction by SPI time series. It was found that, using loglinear regression method, the accuracy of predictions for 2-month lead predicted by SPI time series was higher than those predicted by SRI time series. When we divided the SPI and SRI time series into 2 sub-periods (pre- and post-1980 where land cover changed), we got the same drought class prediction as that predicted by the entire SPI and SRI time series, which illustrated that changes in land use did not affect predictions of hydrological drought classes in the Luanhe river basin. It could be concluded that loglinear prediction of drought class transitions is a useful tool for short term hydrological drought warning, and the results could provide significant information for water resources managers and policy makers to mitigate drought effects.     

人类活动影响下塔里木河流域气象干旱向水文干旱传播的规律

为了解人类活动影响下塔里木河流域气象干旱向水文干旱传播的规律,基于标准化降水指数(SPI)和径流干旱指数(SDI)分析了气象、水文干旱的变化特征,探讨了人类活动对气象干旱向水文干旱传播规律的影响。研究结果表明：源流区气象、水文干旱均呈减弱趋势,干流气象干旱呈减弱趋势,水文干旱与之相反;随时间尺度增大,干旱历时延长;源流区气象、水文干旱以及干流气象干旱的发生频率受人类活动影响后(1993年后)均降低,仅干流水文干旱的发生频率升高;受人类活动影响后,源流区不同季节气象干旱向水文干旱的传播时间均变长,干流干旱传播时间除春季外均缩短;源流区干旱传播时间延长与气候变化有关,而干流干旱传播时间缩短主要是受人类活动的影响。     

Construction of an optimized comprehensive drought index for agricultural watersheds in cold regions and its applicability analysisEI北大核心CSCD

以挠力河流域为寒区农业流域典型区,构建融合多源信息的综合干旱指数用于寒区农业流域干旱特征的评估,并分析其适用性。基于构建的SWAT模型模拟挠力河流域水文气象要素,计算单一的标准化降水蒸散发指数(SPEI)、标准化土壤湿度指数(SSI)和标准化径流指数(SRI),运用主成分分析法和熵权法分别对3种单一干旱指数赋权,通过最小偏差法计算最优组合权重,构建融合气象干旱、农业干旱和水文干旱信息的综合干旱指数(OCDI)。结果表明:OCDI的干旱事件监测结果与历史干旱事件吻合度较高,综合考虑多时间尺度下的OCDI对于挠力河流域干旱状况描述更为准确和全面;3种单一干旱指数监测的干旱程度空间分布差异明显,融合多源信息的OCDI能够从气象干旱、农业干旱和水文干旱多角度揭示挠力河流域综合干旱特征;OCDI与不同类型单一干旱指数均有较高的相关性,在挠力河流域上游对于干旱的综合表征能力更优且年尺度的OCDI综合表征能力优于季尺度和月尺度;OCDI能够较好地识别和区分该流域的综合干旱程度,随着OCDI所识别综合干旱程度的加重,流域实际受旱面积相应增大。     

Future Hydrological Drought Analysis Considering Agricultural Water Withdrawal Under SSP Scenarios

Hydrological drought is assessed through river flow, which depends on river runoff and water withdrawal. This study proposed a framework to project future hydrological droughts considering agricultural water withdrawal (AWW) for shared socioeconomic pathway (SSP) scenarios. The relationship between AWW and potential evapotranspiration (PET) was determined using a deep belief network (DBN) model and then applied to estimate future AWW using projections of the twelve global climate models (GCMs). 12 GCMs were bias-corrected using the quantile mapping method, climate variables were generated, and river flow was estimated using the soil and water assessment tool (SWAT) model. The standardized runoff index (SRI) was used to project the changes in hydrological drought characteristics. The results revealed a higher occurrence of severe droughts in the future. Droughts would be more frequent in the near future (2021–2060) than in the far future (2061–2100) and more severe when AWW is considered. Droughts would also be more severe for SSP5-8.5 than for SSP2-4.5. The study revealed that the increased PET due to rising temperatures is the primary cause of the increased drought frequency and severity. The AWW will accelerate the drought severities in the future in the Yeongsan River basin.

     

渭河流域水文干旱历时-烈度相依结构动态变化与驱动力分析

变化环境下,探究干旱多属性相依结构动态变化及其驱动力,对区域干旱风险管理具有重要意义。以渭河流域为研究对象,应用Copula函数的极大似然比(Copula-based Likelihood-ratio, CLR)方法,对水文干旱历时-烈度相依结构进行变异诊断,分析变异前后特征;从气候变化(气象因子、气象干旱特征)与人类活动的角度,阐明水文干旱历时-烈度相依结构可能的驱动因素,获得影响因子重要性排序。结果表明：(1)华县、张家山、状头站水文干旱历时-烈度相依结构分别在1993年、1982年、1994年发生变异;(2)在相对长的历时下(华县站9～12个月、状头站5～12个月),华县、状头站相同历时下,变异点前后的烈度增加,且随着历时变长,烈度增加的幅度上升,干旱加剧态势明显;(3)除气象干旱对水文干旱演变的影响外,水文干旱历时-烈度相依结构的动态变化主要受水分“需求侧”因子(人类取用水、潜在蒸散发)的驱动。总体而言,研究成果为干旱多属性相依结构的非平稳性检测提供了一种新的思路,所提框架可推广应用于其他流域。     

Hydro-Climatological Drought Analyses and Projections Using Meteorological and Hydrological Drought Indices: A Case Study in Blue River Basin, Oklahoma

Understanding the characteristics of historical droughts will benefit water resource managers because it will reveal the possible impacts that future changes in climate may have on drought, and subsequently, the availability of water resources. The goal of this study was to reconstruct historical drought occurrences and assess future drought risk for the drought-prone Blue River Basin in Oklahoma, under a likely changing climate using three types of drought indices, i.e., Standardized Precipitation Index (SPI), Palmer Drought Severity Index (PDSI) and Standardized Runoff Index (SRI). No similar research has been conducted in this region previously. Monthly precipitation and temperature data from the observational period 1950?C1999 and over the projection period 2010?C2099 from 16 statistically downscaled Global Climate Models (GCM) were used to compute the duration, severity, and extent of meteorological droughts. Additionally, soil moisture, evapotranspiration (ET), and runoff data from the well-calibrated Thornthwaite Monthly Water Balance Model were used to examine drought from a hydrological perspective. The results show that the three indices captured the historical droughts for the past 50?years and suggest that more severe droughts of wider extent are very likely to occur over the next 90?years in the Blue River Basin, especially in the later part of the 21st century. In fact, all three indices display lower minimum values than those ever recorded in the past 50?years. This study also found that SRI and SPI (PDSI) had a correlation coefficient of 0.81 (0.78) with a 2-month (no appreciable) lag time over the 1950?C2099 time period across the basin. There was relatively lower correlation between SPI and PDSI over the same period. Although this study recommends that PDSI and SRI are the most suitable indices for assessing future drought risks under an increasingly warmer climate, more drought indices from ecological and socioeconomic perspectives should be investigated and compared to provide a complete picture of drought and its potential impacts on the dynamically coupled nature-human system.     

黄河流域气象干旱与水文干旱时空特征及其传递关系EI北大核心CSCD

基于标准化降水蒸散指数(SPEI)和标准化径流指数(SRI),比较了黄河流域气象干旱和水文干旱的时空分布差异,分析了二者时间尺度上的关联性,并选取典型干旱事件进一步探讨了两种干旱类型的传递关系。结果表明:两种干旱类型空间上有相似的趋势和频次,但在黄河源区和黄河中南部(渭河流域)差异显著,其干旱历时均有随年代延长的趋势,水文干旱历时增长尤为明显;在时间尺度上,SPEI与SRI在大部分区域基本一致,但在黄河源区和渭河流域差异较大,尤其是短时间尺度上差异更显著;气象干旱与水文干旱并非一一对应,多场短历时间断气象干旱受时滞效应、异常气象波动等影响,可能引发一场长历时连续水文干旱或多场短历时间断水文干旱,一场长历时连续气象干旱强度衰减可能引发多场短历时间断水文干旱。     

抚河流域气象干旱向水文干旱传播的影响机制研究

气象干旱是水文干旱发生的前兆,探究影响气象干旱向水文干旱传播的主要因素对建立有效的基于气象干旱的水文干旱监测预警具有重要意义。以抚河流域为例,采用标准化降水指数和标准化径流指数分别评估气象干旱和水文干旱,并构建基于流域分布式二元水循环模型的干旱传播评估方法,采用多因素综合影响贡献量分解法量化气候变化和人类活动对干旱传播变化的贡献。结果表明：建立的抚河流域分布式二元水循环模型模拟流域出口断面流量的纳什效率系数大于0.85,相对误差在5%之内;气象干旱向水文干旱传播关系变化的时间是1980s—1990s。相对于1956—1990年,1991—2019年气象干旱向水文干旱的传播率降低了8.3%;在气象干旱向水文干旱传播的影响中,气候变化的减缓作用占主导地位,贡献量为-9.9%;其次是人类活动的加剧作用,贡献量为1.6%;降水作为干旱的主要致灾因子,变化期增加了144.3 mm,这对于减弱气象干旱向水文干旱传播的敏感性起到主要作用。     

变化环境下我国干旱灾害的综合应对

干旱是我国主要自然灾害之一,发生频率大,影响范围广,其不仅具有普遍性、季节性、连续性和地域性等多样特征,同时还影响着我国的粮食安全,以及水循环及其伴生水环境、水生态和水沙过程。因此,系统识别干旱成因,综合应对变化环境下的干旱,已成为我国经济社会发展过程中亟待解决的关键问题之一。我国干旱既受到全球气候变化的影响,也受到经济社会发展过程中非理性水土资源开发活动影响;同时,强调自然成因和以"危机管理"为主要范式的干旱应对方略也未能有效减缓干旱危害。进一步提出我国干旱综合应对在从"危机管理"向"风险管理"转变的同时,还应构建物理机制统一的水资源及伴生过程模拟平台和干旱风险评价指标体系,进而做出相应的应对策略。     

西南地区气象干旱向水文干旱传播的特征

为了解西南地区气象干旱向水文干旱传播的特征,采用西南地区1968—2017年101个气象站观测资料和8个水文站月径流资料,计算了标准化降雨蒸散发指数(SPEI)和标椎化径流指数(SRI),基于皮尔逊相关系数(PCC)确定了干旱响应时间并结合游程理论识别、融合和剔除干旱事件,构建了线性干旱传播模型并确定了西南地区部分流域气象干旱向水文干旱传播的触发阈值。结果表明：西南地区干旱响应时间为2～7月;水文干旱敏感度分布与气象干旱传播率分布较为一致;干旱烈度传播阈值较小的流域,水文干旱事件历时更长。     

A Non-Stationary Reconnaissance Drought Index (NRDI) for Drought Monitoring in a Changing Climate

Traditionally, drought indices are calculated under stationary condition, the assumption that is not true in a changing environment. Under non-stationary conditions, it is assumed the probability distribution parameters vary linearly/non-linearly with time or other covariates. In this study, using the GAMLSS algorithm, a time-varying location parameter of lognormal distribution fitted to the initial values (α₀) of the traditional Reconnaissance Drought Index (RDI) was developed to establish a new index called the Non-Stationary RDI (NRDI), simplifying drought monitoring under non-stationarity. The fifteen meteorological stations having the longest records (1951–2014) in Iran were chose to evaluate the NRDI performances for drought monitoring. Trend analysis of the α₀ series at multiple time windows was tested by using the Mann-Kendall statistics. Although all stations detected decreasing trend in the α₀ series, eight of them were significant at the 5% probability level. The results showed that the time-dependent relationship is adequate to model the location parameter at the stations with the significant temporal trend. There were remarkable differences between the NRDI and the RDI, especially for the time windows larger than 6 months, implying monitoring droughts using the NRDI under non-stationarity. The study suggests using the NRDI where the significant time trend appears in the initial values of RDI due to changing climate.     

气候变化对滇中引水工程取水影响分析

气候变化正在逐渐改变全球的水循环现状,并对水文水资源及其应用产生重大影响。在联合国政府间气候变化专门委员会(IPCC)对气候变化趋势进行分析的基础上,优选近期、远期气候变化情景,并模拟在未来气候变化情景下金沙江流域干流主要断面的逐日流量过程,用以分析气候变化对金沙江干流石鼓断面水文干旱以及对滇中引水工程取水的影响。研究结果表明:受未来可能的气候变化影响,金沙江干流石鼓断面的水文干旱发生强度和发生频率都将有所增加,远期较近期具有高的不确定性;滇中引水工程不可取水天数和可调水量将会增加,但总体而言对工程的不利影响较小。     

非稳态条件下的中长期径流耦合预报方法

气候变化会导致水文序列的非稳态性,从而给水文预报带来新的挑战。以疏勒河上游为例,提出了一种适于非稳态条件下的新的中长期径流预报方法。根据疏勒河径流的补给来源及其受气候变化的影响,按照时间序列模型的思路,依次提取趋势项和周期项,对剩余的随机项采用基于水文-气象遥相关模型,构建了时间序列与水文-气象遥相关的耦合模型。对比分析时间序列法、水文-气象遥相关法和耦合预报法对昌马堡站径流预报的结果,发现耦合预报方法不仅精度最高、模型可信度最高,而且可以描述非稳态的趋势性变化。