黄河流域近50a极端降水指数的时空变化

根据黄河流域80个气象站1957—2008年的逐日降水资料,利用Rclim Dex软件选用了10个极端降水指数,采用Mann-Kendall趋势检验法和线性回归分析法,研究了极端降水指数在年和季节尺度上的时空变化特征。结果表明:极端降水指数中除了Rx5DAY呈显著下降趋势、SDII呈上升趋势外,其他8个指数均呈非显著下降趋势;从极端气候指数的四季变化来看,Rx1DAY和Rx5DAY在夏、秋季的空间分布相似,且数值大于春、冬季的;黄河流域降水量呈逐年减小趋势,极端降水指数的变化趋势不明显,但存在时空差异。     

长江流域降水量和径流量长期变化趋势检验

采用TFPW-MK(Mann-Kendall test with trend-free pre-whitening)趋势检验法,对20世纪50年代以来长江流域154个气象站降水量和26个主要水文站径流量的变化趋势进行了显著性检验.结果显示:①流域年降水总量整体变化趋势不显著,但各季节和月份的降水量存在的增加或减少趋势显著,尤其是在上世纪90年代期间降水量分布存在一定的变异,在流域空间分布上不仅出现了降水显著增加的集中区(洞庭湖和鄱阳湖水系),而且还出现降水显著减少的集中区(四川盆地和汉江上游),在降水的年内时间分布上也存在着趋于集中的态势,表现在夏季降水量增加、而秋季和春季降水量减少.②流域内各主要支流径流量变化趋势与其降水量变化趋势基本一致,夏季长江中下游地区径流量增加趋势显著,而秋季长江上游和汉江地区径流量则呈减少趋势,相对而言干流径流量的变化趋势并不显著.     

1960—2018年嫩江流域极端降水事件时空变化特征

本文选取嫩江流域12个站点1960—2018年逐日降水资料,采用线性回归、Mann-Kendall检验、小波分析、R/S分析等方法,分析了该流域极端降水事件的时空变化特征及未来变化趋势.结果表明:流域平均年降水量、大雨日数、日最大降水量、强降水量等4个极端降水指数均表现出上升趋势,但趋势不显著;各极端降水指数时间序列均存在3个明显的周期变化;流域年降水量与强降水量空间分布趋势均为由上游至下游逐渐递减,暴雨中心出现在嫩江右岸支流雅鲁河上,各极端降水指数在流域内的多数地区均表现为正增长;未来流域多数地区各极端降水指数的变化趋势仍将以上升为主.     

近55年珠江上游流域降水演变规律

采用线性回归、5年滑动平均、Mann-Kendall趋势检验及小波分析等方法,对珠江上游流域1954年-2008年降水序列进行研究分析。结果表明:近55年来,珠江上游流域年降水量总体呈不显著增加趋势;各季节降水均呈现无显著变化趋势;除1月降水增加显著外,其余各月均无明显趋势变化。流域各站点的年、季节降水趋势基本上也无显著变化。除年降水量在1963年发生了显著突变外,季节和大部分月降水均无显著突变发生。年和季节降水量的相位变化时间尺度大体一致,均存在多年尺度的变化特征。     

城市化对长江三角洲地区降水变化趋势影响初探

根据长江三角洲地区城市化程度,选择1956—2007年和城市化发展较为迅速的1981—2007年两个时段进行研究,基于长江三角洲地区35个国家基本/基准站1956—2007年52a日降水量资料,分析了两个时段长江三角洲降水量的年和季节变化特征、降水的气候趋势系数和气候倾向率的空间分布差异,以及城市化对降水变化趋势的影响。初步的研究结果表明:1956—2007年长三角地区年降水呈减少趋势,城市化快速期减少趋势明显加快。两时期季节降水量有相同的变化趋势,但变化趋势明显程度和变化速率差别很大,城市化快速期变化剧烈,年降水变化趋势在城市化快速期几乎呈现出与整个52a时段相反的空间分布,城市化快速期长江三角洲中部大片区域变干趋势显著。     

基于TRMM 3B42数据的1998-2010年中国暴雨时空特征分析

基于TRMM 3B42数据,构建5个年尺度时间序列参数,借助GIS空间分析和数学方法,揭示和分析1998-2010年暴雨降水的格局与过程特征。研究表明:13年来,年暴雨降水总量与年降水总量均呈缓慢下降的趋势,且空间格局相似,年暴雨降水比例时间波动较显著;暴雨集中分布区年降水以及年暴雨降水的时间波动均比较明显,年暴雨频次的时间波动较小但空间差异显著;暴雨降水空间分布在东西方向的差异性明显强于南北方向;年暴雨降水呈现向东北方向偏移的趋势;5个变量的变化趋势均表现出较强的空间差异性,且大部分像元呈增加(或减少)但统计不显著的趋势。     

近60年福建地区降水及时空演变特征研究

基于1961—2020年福建省年降水和季节降水数据,采用线性回归、M-K突变检验、Morlet小波等方法,分析福建省近60年年均降水变化趋势、突变特征、时空序列周期的降水特性。结果表明：近60年福建省年降水整体表现为上升趋势,倾向率为1.2695mm/a;春、秋季年均降水整体都表现为不显著下降趋势,夏季降水呈现显著性上升趋势,冬季降水表现为不显著上升趋势,突变检验以及线性回归趋势分析结果显示1961—2020年年降水整体呈现不显著上升趋势,倾向率和趋势变化及结果一致。年降水55年为第一主周期,6、19、12年为次周期,55年主周期整体变现为枯-丰-枯-丰-枯循环交替周期变化,目前在正处在偏枯周期,未来在5～6年降水表现为减少趋势。该研究为福建省季节降水和年均降水变化趋势和空间分布提供参考依据。     

黄河流域降水演变规律研究

基于黄河流域及其周边地区1000多个水文气象站近50年的月降水资料所生成的整个流域及其29个三级区的面雨量过程,采用多种时间序列分析方法,研究了黄河流域降水的随机性、趋势性和周期性。结果表明：黄河流域各三级区降水量Hurst系数的分布范围在0.449～0．644之间,说明其具有长期弱相关性;Kendall秩次相关检验结果表明黄河流域降水减少的趋势性不明显,从三级区看,大通河享堂以上等7个三级区降水有一定的减少趋势;黄河流域降水的短周期为准3年周期,中长周期一般表现为l1年和22年左右的周期。     

考虑变异的广西降水时空变化特征研究

基于广西22个气象台站1956年～2018年的逐日降水数据,采用经验正交函数(EOF)、Mann-kendall、小波分析法和R/S分析法等方法,对广西降水量的时空变化、周期规律和未来趋势进行了分析。结果表明,广西降水在空间上总体呈现从西南向东北先减少后增加的特点,但存在桂东北、桂南两个高值区;EOF分解得到的前三个模态可以较好地反映广西年降水的3种空间分布类型;通过多种突变方法的综合诊断,得出广西年降水在2012年发生变异。利用Morlet分析广西降水在多时间尺度下的周期变化,发现降水量序列存在3个时间尺度;广西降水量的Hurst指数大于0.5,说明未来变化呈增长趋势。     

黄河流域近40年气候变化的时空特征

黄河流域是我国主要的气候敏感区之一,气候变化对其生态环境演变与经济社会发展有显著影响。本文利用欧洲中期天气预报中心ERA5再分析资料分析了黄河流域过去40年的温度、降水、水汽通量散度、蒸散和荒漠化风险等的演变特征,结果发现:1979—2019年黄河流域四季均呈现明显增温趋势,其中春季增温最为明显;季节性降水的变化差异显著,春季和夏季降水呈现下降趋势,秋季降水增加;黄河流域空中水汽以辐合为主,过去40年黄河流域上游水汽辐合年际波动最小,中游次之,下游最大;黄河流域蒸散整体呈现减少趋势,其中增加趋势集中在上游地区;黄河流域荒漠化风险整体处于中等风险以上,呈现由南向北加剧的空间分布,1982—2014年黄河流域荒漠化风险呈现下降趋势。本研究厘清了全球气候变化背景下黄河流域蒸散、水汽输送和降水等水循环过程的变化规律,能够为维护黄河流域地区生态安全、防范重大气象灾害风险提供科学依据。     

长江中游四大家鱼发江生态水文因子分析及生态水文目标确定

基于长江中游四大家鱼发江量历次调查数据,采用宜昌站作为长江中游水文情势变化分析的控制站,基于其1900~2004年共105年的日径流资料,采用每年5~6月涨水过程数、总涨水日数、平均每次涨水过程日数等3项生态水文指标,分析了四大家鱼发江量与3项生态水文因子的变化关系,认为产卵场所处江段每年5~6月的总涨水日数是决定家鱼苗发江量多寡的一个重要环境因子。根据IHA方法,对宜昌站105年来的生态水文指标分析表明,长江宜昌站生态水文过程的改变并不明显,5~6月总涨水日数变化趋势不显著,显示长江中游影响四大家鱼苗发江量的生态流量过程改变不明显,与前人得出的葛洲坝枢纽修建后四大家鱼的产卵条件和卵苗江汛规律没有变化这一认识一致。但是,随着三峡水库的运行,下游河道的生态环境流量过程会有较大改变,本文建议三峡水库的调控以保障长江中游每年5~6月的总涨水日数维持在22.1±7.2范围内为生态水文目标,即可从生态环境流量过程方面补偿水利工程对中游四大家鱼鱼苗发江量的影响。     

Seminar on Water and Energy,Stockholm, Sweden,August 21, 2005

Abstract

In Europe the implementation of the Water Framework Directive (WFD) will have major implications for water resources management. Part of the Directive requires Member States to implement a comprehensive system of controls (licences) on the allocation and abstraction (withdrawal) of surface and groundwater resources. This paper describes the development of a procedure to help assess and set abstraction licences for agricultural irrigation. The methodology is described with reference to Scotland, a country with limited abstraction control previously and where irrigation is supplemental to rainfall. The methodology combines spatial climatic information using a Geographical Information System (GIS) with data derived from a water balance computer model. The procedure enables the volumetric irrigation demand in a ‘design’ dry year for a given site to be estimated, taking into account local variations in climate, soil type, land use and irrigation practices. The approach provides a scientifically robust framework to allow the regulatory authority to assess the ‘reasonable’ water requirements of individual irrigators and hence develop allocations to satisfy the range of competing demands (e.g. agriculture, industry, and environment) on water resources. The methodology is applicable in other temperate countries where water abstraction controls are required and where appropriate datasets are available. The application of the procedure and its methodological limitations are described.     

Stakeholder-driven,enquiry-driven,or stakeholder-relevant,enquiry-driven science?

There is currently debate within the international hydrological community on whether hydrological science should give priority to providing measurements, knowledge, and understanding pre-determined as being needed by stakeholders, or priority to more basic enquiry-driven science that will stimulate the continued health and growth of hydrology as an important Earth science discipline. Two recent major international initiatives in hydrology reflect these two perspectives. One, the Hydrology for the Environment, Life, and Policy (HELP) program, is primarily fostered by UNESCO-IHP and is focused on stimulating the stakeholder-driven hydrological science required in specific catchments that have become members of a global network. The second, the decade on Prediction in Ungauged Basins (PUB), which is appropriately managed by IAHS, is primarily driven by scientific enquiry and is focused on creating new scientific methods and understanding, albeit with practical application ultimately in mind. This paper summarizes the nature, origins, growth, and progress of these two international programs but also describes the subtly different approach that has been adopted by the U.S. National Science Foundation's (NSF's) Center for Sustainability of semi-Arid Hydrology and Riparian Areas (SAHRA). NSF is a federal agency whose primary goal is to ‘enable the future’ by stimulating novel science. Because SAHRA is a federally-funded entity supported by an agency with this goal, the Center clearly cannot operate in stakeholder-driven, response mode in competition with the already effective private U.S. consultancy industry. Nonetheless, SAHRA's mission is to create knowledge and build understanding that will enhance the prospects of sustainable water management in semi-arid regions, especially the southwestern U.S. To resolve this apparent conflict, SAHRA looks ahead to future stakeholder needs and builds its research agenda around selected critical stakeholder-relevant questions that require substantial and sustained investment in basic, multidisciplinary, enquiry-driven science. This paper describes SAHRA's approach and reports on associated research and outreach activities.     

Growth,Reproduction, Mortality,Distribution, and Biomass of Freshwater Drum in Lake Erie

Predominant age-groups in the Lake Erie freshwater drum Aplodinotus grunniens population were 3, 4, and 5 as determined from gill net, trap net, bottom trawl, and midwater trawl samples. Age and growth calculations indicated that females grew faster than males. However, the length-weight relation did not differ between sexes and was described by the equation: log W = ?5.4383 + 3.1987 log L. Some males became sexually mature at age 2 and all were mature by age 6. Females matured 1 year later than males. Three sizes of eggs were present in ovaries; the average total number was 127,000 per female for 20 females over a length range of 270 to 478 mm. Seasonal analysis of the ovary-body weight ratio indicated that spawning extended from June to August. A total annual mortality rate of 49% for drum aged 4 through 11 was derived from catch-curve analysis. Freshwater drum were widely distributed throughout Lake Erie in 1977–1979, the greatest concentration being in the western basin. They moved into warm, shallow water (less than 10 m deep) during summer, and returned to deeper water in late fall. Summer biomass estimates for the western basin, based on systematic surveys with bottom trawls, were 9,545 t in 1977 and 2,333 t in 1978.     

水-能源-粮食纽带关系定量研究方法综述

在总结水-能源-粮食纽带关系研究中, 使用频率较高或潜力较大的 8 种水-能源-粮食纽带关系定量研究方法为: 水-能源-粮食纽带关系工具 2.0( WEF Nexus Tool 2.0) ; 生命周期评价( LCA) ; 可计算的一般均衡模型( CGE) ; 系统动力学模型( SD) ; 气候、土地、能源与水资源策略( CLEWS) ; 基于社会生态系统代谢的多尺度综合评价( MuSIASEM ) ; 市场配置/ 市场配置系统集成模型( MARKAL/ TIMES) 和水资源评价规划模型-长期能源替代规划系统 ( WEAP2LEAP) 。通过总结各研究方法的产生、发展及特性, 并引用案例讨论其适用范围, 分析其优缺点和在使用 时需要注意的问题。在此基础上, 对未来水2能源2粮食纽带关系定量研究方法的发展趋势进行讨论, 认为伴随可持 续发展问题关注度的上升与水-能源-粮食纽带关系内在机理的挖掘, 未来的水-能源-粮食纽带关系定量研究方法将 更加注重量化的精确性和数据的互通以及跨学科研究和多方法的耦合。本文可为水-能源-粮食纽带关系定量研究方法的选择和更新优化提供参考。     

Survival,Growth, and Movement of Subadult Humpback Chub,Gila Cypha,in the Little Colorado River,Arizona

Ecologists estimate vital rates, such as growth and survival, to better understand population dynamics and identify sensitive life history parameters for species or populations of concern. Here, we assess spatiotemporal variation in growth, movement, density, and survival of subadult humpback chub living in the Little Colorado River, Grand Canyon, AZ from 2001–2002 and 2009–2013. We divided the Little Colorado River into three reaches and used a multistate mark‐recapture model to determine rates of movement and differences in survival and density between sites for different cohorts. Additionally, site‐specific and year‐specific effects on growth were evaluated using a linear model. Results indicate that summer growth was higher for upstream sites compared with downstream sites. In contrast, there was not a consistent spatial pattern across years in winter growth; however, river‐wide winter growth was negatively related to the duration of floods from 1 October to 15 May. Apparent survival was estimated to be lower at the most downstream site compared with the upstream sites; however, this could be because in part of increased emigration into the Colorado River at downstream sites. Furthermore, the 2010 cohort (i.e. fish that are age 1 in 2010) exhibited high apparent survival relative to other years. Movement between reaches varied with year, and some years exhibited preferential upstream displacement. Improving understanding of spatiotemporal effects on age 1 humpback chub survival can help inform current management efforts to translocate humpback chub into new locations and give us a better understanding of the factors that may limit this tributary's carrying capacity for humpback chub. Published 2014. This article is a U.S. Government work and is in the public domain in the USA.