1970-2016年气候变化对渭河源头清源河流域降水和地表径流的影响

[目的]探究1970—2016年渭河源头清源河气温、降水、径流变化特征及相互关系,为明确该区域气候变化对降水和径流的影响及模拟研究径流演变过程提供依据。[方法]在分析气候要素变化和径流等年际变化规律和相互关系的基础上,采用3种气温修正气候水文模型与流域基本水文模型相比较的方法研究气候变化对径流的影响。[结果]1994—1995年是清源河流域主要气象水文要素变化的分界线,1970—1994年,流域年平均气温、年降水量、径流量变化不大;1995年之后,气温持续升高,而降水、径流则出现了整体降低趋势,2010—2016年平均温度比1970—1974年升高0.9℃,升幅15.79%;年降水量、径流量分别减少13.48%,31.82%。3个气候水文模型MQPT_1-1,MQPT_2-1和MQPT_3-1对年降水—径流过程模拟精度均比一般水文模型高,尤其是气温扰动法修正模型MQPT_2-1平均模拟误差仅为3.03%,比不考虑气候变化的流域水文模型精度提高11.62%。[结论]渭河源头清源河小流域近50 a气温变化对径流影响非常明显,尤其是1995年之后;在径流模拟分析中必须考虑气温等主要气象因子的影响。     

艾比湖流域气候变化及对地表水资源的影响

利用艾比湖流域逐月气温、降水数据,结合流域地表径流和艾比湖湖泊面积数据,分析了1961—2010年流域气候要素变化趋势和突变特征,探讨了气候变化对流域地表水资源的影响。结果表明:(1)近50a来艾比湖流域气温、降水均呈波动上升趋势,气候由暖干型向暖湿型转变。冬季升温对流域气温增幅贡献率大,气温在1995年发生突变。冬季降水量增幅明显,夏季只有温泉站点降水量增幅显著,降水量在1984年发生突变;(2)流域年均气温与径流量呈正相关,年降水量与径流量的变化呈显著同步性;(3)流域年平均气温与艾比湖面积大小关系复杂;年平均降水量与湖泊面积的变化趋势趋于同步,1996—1999年这种同步性更明显;(4)气候变化直接影响冰川伸缩与雪线升降,冰川数量和规模均逐渐减小,用水矛盾日益尖锐,影响绿洲社会经济发展。     

白洋淀流域气温、降水和径流变化特征及其相互响应关系

运用Mann-Kendall趋势检验、突变检验和小波分析法,对白洋淀流域1957—2012年7个气象站点气温、降水和3个典型水文站点径流量的变化趋势、突变点及周期性变化进行了分析,并探讨了径流与降水和气温的响应关系,以期为该地区生态环境保护和水资源合理利用提供基础数据支持。结果表明,研究区年均气温呈上升的趋势,并在1988年后上升趋势增大,其中,冬季和春季的气温增幅对气温升高贡献较大;降水量变化相对复杂,整体呈波动下降的趋势,其中,夏季降水量减少幅度最大,达1.72 mm·a~(-1)。受气温升高和降水量的直接影响,典型站点径流量呈明显下降趋势,并在年际尺度上与气温呈负相关,与降水变化呈显著正相关;在年内尺度上,则与气温和降水变化呈显著正相关。夏季径流量减少幅度最大,阜平、倒马关和紫荆关站分别下降0.85 m~3·s~(-1)·a~(-1)、0.72 m~3·s~(-1)·a~(-1)和0.66 m~3·s~(-1)·a~(-1)。3个指标的周期性变化都比较明显,其中径流和降水的波动变化基本一致,表明径流对降水的响应比较突出。径流变化不仅受气温和降水的影响,还受到水利工程建设、各类农业措施等多种因素的影响。     

基于SWAT模型的气候变化下水文响应分析——以福建省长汀县朱溪小流域为例

本文以长汀县河田地区朱溪小流域为研究区,基于多年的气象、水文数据及高程数据模型、土地利用图、土壤类型图等,构建朱溪小流域SWAT模型。本文在假设下垫面条件不变的情况下应用假定气候情景法,通过改变日最高、最低气温值和逐日降雨量值构建15种不同的气候条件情景定量模拟分析气候变化对朱溪小流域径流的影响。研究结果表明:降水和温度的变化共同影响着朱溪小流域的产流过程,朱溪小流域的径流量与降雨量呈现正相关关系,与气温呈现负相关关系;相对于温度变化对朱溪小流域径流的影响,降雨量对于研究区径流量的影响更大。     

滦河流域气候变化的水文响应研究

以滦河流域为研究区,基于未来气候变化研究成果建立了16种气候变化情景,结合SWAT分布式水文模型模拟了不同气候变化情景下的水文过程,对滦河流域气候变化的水文响应进行了分析。结果表明:SWAT模型可以较好地模拟滦河流域的月流量过程,在研究区具有较好的适用性;流域气温升高将会导致蒸发量增加、径流减少。在以升温为主、降水变化存在很大不确定性的情况下,滦河流域径流量可能进一步衰减。在未来降水增加的情况下,流域年均地表径流增加趋势的空间差异显著,尤其是流域下游的迁西县等地增加幅度超过12mm,研究结果将为变化环境下滦河流域的水资源管理提供参考。     

不同气候变化情景模式对大凌河流域径流的影响研究

为定量研究不同气候变化情景对大凌河径流的影响,探索气候变化下大凌河径流响应规律,基于分布式水文模型SWAT模型,通过设定不同气候变化情景(假定气温±2℃,降水量变化±10%),定量分析不同气候变化情景对大凌河径流的影响。研究成果表明:模型适合于大凌河径流模拟,模型参数率定期和验证期年径流模拟相对误差均在10%以内,确定性系数均达到0.8以上;气温升高2℃,流域径流增加5.8%,降雨量减少10%,流域径流量减少4.7%;降雨量增加10%,流域径流量增加4.3%。研究成果对于大凌河应对气候变化下水资源保护以及利用可提供参考。     

气候变化对开都河流域径流的影响研究

利用SWAT模型模拟开都河流域的径流变化,并采用1990—2009年的水文站点径流数据进行精度验证,然后设定气候变化情景,模拟不同气候条件下径流的响应特征。结果表明:模拟结果与实测径流较吻合,剔除异常年份（1994年、1995年）后,校准期（1990—2000年）效率系数为0.58,平均相对误差为-5.7%,线性拟合度为0.8;验证期（2000—2009年）的结果与校准期接近,均达到了模型的评价标准,说明SWAT模型在开都河流域的适用性较好。基于此,采用任意情景设置方法,设置了25种气候变化（气温和降水）组合情景,研究了该流域对气候变化的响应,结果表明,气候变化对径流量的影响较为显著,降水增加或气温降低均会导致径流量增加,流域未来年均径流变化的主要影响因素是降水,温度的影响相对较弱。     

乐安河流域水文气象要素变化特征分析

根据乐安河流域1954—2013年水文、气象资料,采用非参数统计方法 Mann-Kendall和Spearman秩相关检验对其降水、气温、暴雨、干旱和径流变化进行趋势分析。结果表明:乐安河流域降水总体呈弱减少趋势,其中春、秋、冬季降水量呈减少趋势,夏季降水量呈增加趋势;平均气温呈极显著增加趋势;全年干旱时间呈上升趋势,除了20世纪60年代其他时期整体上表现为秋冬旱出现频率高于夏旱;流域径流变化与年降水量总体变化趋势基本吻合。以上结果说明,该流域季节性干旱和洪涝灾害有进一步加剧的风险,需要采取措施应对全球气候变化对区域水资源的影响。     

西北内陆县域气候变化及其对河川径流的影响

根据民乐县及祁连县气象站点1958-2008年气温、降水资料,结合民乐县历年水文数据,利用Mann-Ken-dall秩相关分析法等方法分析了民乐、祁连县1958-2008年气温、降水和民乐地表径流量的变化,在建立定量化关系的基础上研究了气候变化对民乐县地表径流的影响并对未来径流量做出预测.研究表明,气温的变化可分为基准期(1958-1986年)和增温期(1987-2008年),后者增温速率达0.62℃/10 a,且全年各季度整体增加;降水量总体上呈上升趋势,增幅为19.5 mm/10 a,突变年(1978年)后降水量的波动性增大;历年降水量有减少趋势,受气候变化影响,径流量的年际变化增大,气温与降水对径流变化的贡献相反.未来径流量还有减小的趋势,对此,提出了调整产业和种植结构、节水灌溉、综合利用水资源等措施以应对.     

气候变化对西北内陆寒区地表水资源的影响研究

气候是形成和影响地表水资源的重要因素。在全球气候变暖的背景下,内陆寒区出山径流量的变化对中下游地区社会经济发展、防汛抗旱和生态环境保护有着直接的影响。以内陆高寒区甘肃省石羊河流域为研究区,通过天然径流量对气候变化的敏感性分析,假定影响径流变化的主要因素为降水、气温,然后根据未来气候的可能变化趋势,设置气候情景方案,模拟计算不同情景下的地表径流量变化趋势,从而研究气候变化对寒区流域地表水资源的影响。     

Response of snowmelt hydrology to climate change

In mountainous regions where the accumulation and melt of seasonal snow cover are important for runoff production, the timing and quantity of water supply could be strongly affected by regional climate change, particularly altered temperature and precipitation regimes.In this paper, the hydrological response to climate change scenarios is examined using a semi-distributed snowmelt runoff model. The model represents an improvement over simple temperature-based models, in that it incorporates the net radiation into the snowpack. Thus it takes into account the basin's topography and slope orientation when computing snowmelt. In general, a warmer climate is expected to shift snowmelt earlier into the winter and spring, decreasing summer runoff. The effects of other potential climate changes (such as precipitation and cloudiness patterns) are explored. The uncertainties in these predictions are discussed.     

不同宽度硬头黄竹林河岸缓冲带对地表径流的拦截效应

利用2008年河岸缓冲带硬头黄竹人工林的降雨量、穿透降雨量和树干径流量来计算林冠层截留量,并在冬、夏两季分别对林内枯落物和取样土壤测定最大持水能力,建立5m至40m不同缓冲带宽度的简易径流场观测地表径流量.结果表明:全年林冠截留总量为315.6 mm,占全年降水量的32.4%,林冠截留量随着降雨量的增加而增加,但林冠截留率反而减小,选取24组不同雨量级的降雨量(P)与林冠截留量(I)数据进行拟合,方程为:I=0.7791P~(0.78).硬头黄竹林内枯落物生物量为2.87 t/hm~2,其最大持水量为9.13 t/hm~2,是枯落物自身干质量的3.2倍,但由于>10 mm的降雨在时间分布上具有连续性,枯落物对降雨的截留效应明显被削弱.实际截留量只占全年降水量的9.2%.硬头黄竹林对林内土壤物理性质起到了明显的改善作用,土壤容重随着土壤深度的变浅而减小,加快了地表径流的人渗速率,土壤的最大截留能力为497.36 t/hm~2.地表径流量随河岸缓冲带宽度增加而减小,20m宽的河岸缓冲带就可截留40.7%,而当缓冲带宽度继续增加,截留效率并没有明显变化.     

Trend and uncertainty analysis of simulated climate change impacts with multiple GCMs and emission scenarios

Trends and uncertainty of the climate change impacts on hydrology, soil erosion, and wheat production during 2010-2039 at El Reno in central Oklahoma, USA, were evaluated for 12 climate change scenarios projected by four GCMs (CCSR/NIES, CGCM2, CSIRO-Mk2, and HadCM3) under three emissions scenarios (A2, B2, and GGa). Compared with the present climate, overall t-tests (n = 12) show that it is almost certain that mean precipitation will decline by some 6% (>98.5% probability), daily precipitation variance increase by 12% (>99%), and maximum and minimum temperature increase by 1.46 and 1.26 °C (>99%), respectively. Compared with the present climate under the same tillage systems, it is very likely (>90%) that evapotranpiration and long-term soil water storage will decease, but runoff and soil loss will increase despite the projected declines in precipitation. There will be no significant changes in wheat grain yield.Paired t-tests show that daily precipitation variance projected under GGa is greater than those under A2 and B2 (P = 0.1), resulting in greater runoff and soil loss under GGa (P = 0.1). HadCM3 projected greater mean annual precipitation than CGCM2 and CSIRO (P = 0.1). Consequently, greater runoff, grain yield, transpiration, soil evaporation, and soil water storage were simulated for HadCM3 (P = 0.1). The inconsistency among GCMs and differential impact responses between emission scenarios underscore the necessity of using multi-GCMs and multi-emission scenarios for impact assessments. Overall results show that no-till and conservation tillage systems will need to be adopted for better soil and water conservation and environmental protection in the region during the next several decades.     

过去(1958-2007)和未来(2011-2060)50年淮河流域气候变化趋势分析

根据淮河流域1958-2007年观测资料和ECHAM5/MPI-OM模式对该流域2011-2060年气候变化的预估结果,分析淮河流域1958-2007年平均气温、极端高(低)温、农业界限温度和年降水量变化,并对2011-2060年气温和降水量变化趋势进行预估。结果表明:(1)淮河流域年平均气温,20世纪90年代以前以降温为主,90年代中后期增温显著;季节变化上,春秋两季气温呈波动增加趋势,冬季增温速率较高,夏季则呈下降趋势,极端气温事件出现次数和温度变化幅度均减小。淮河流域热量资源的时间变化以增温趋势为主,各界限温度初日提前,终日推迟,持续日数和累积温度增加。从区域分布上,流域东部增温趋势强于西部。1958-2007年年降水量和极端降水等无突变性的增加或减少趋势;季节变化上,流域夏季降水量变幅较大。(2)3种排放情景下淮河流域年平均气温升高趋势一致,且SRES-A1B情景升温幅度大于其它两种情景且约在2040年突变增温,3种情景下季节平均气温均为冬季升高最快;未来年降水量有微弱增加,但M-K检测均无显著变化趋势,未来50a淮河流域季节降水仍以春、夏季降水为主,约占全年降水量的70%。     

THE WATER BALANCE OF AN AGRICULTURAL CATCHMENT III THE WATER BALANCE

The catchment of the Kingston Brook has an area of 57 km², mainly under pasture (56%) and arable crops (36%). Changes of soil water content, measured with a neutron probe from April 1969 to March 1973, were analysed to determine evaporation (summer only) and drainage. From measurements of rainfall and runoff, supplemented by Penman estimates of evaporation (in winter), water storage is estimated month by month. Annual mean values (mm) were: rainfall (559), evaporation (398), runoff (157). During the summer, the measured decrease in soil water storage contributed ca 100 mm to evaporation and drainage and there is evidence of delayed recharge (about 30 mm) during the winter. A linear relation between annual rainfall and annual runoff is interpreted in terms of (i) a fixed catchment storage (125 mm); (ii) a small and nearly constant winter evaporation (ca 49mm); (iii) summer evaporation of 125 mm from storage plus a constant fraction (0.57) of contemporary precipitation. Summer evaporation was restricted by the supply of rain in every year from 1969 to 1976. By estimation, 500 mm of summer rain is needed to maintain potential evaporation, and the deficit at which actual evaporation falls below the potential rate was about 40 mm. Replacing the pasture by cereals would increase runoff by about 10% because of the shorter growing season.     

黄土高原晋南旱塬长时间序列冬小麦产量与水量平衡要素动态变化

为揭示黄土高原旱地冬小麦田长期产量及水文变化,以山西省万荣县连作冬小麦为研究对象,分析了冬小麦产量1951—2020年变化趋势及气候年际波动对产量的影响,同时利用Hydrus-1D模型和标定的模型参数模拟了1965—2020年田间水量平衡要素各分量的变化过程。结果表明：试验地冬小麦产量多年平均增产率是31.9 kg/(hm²·a),年际气候变化对冬小麦产量的影响达到±22.4%,其中影响最为显著的气象要素是生育期平均相对湿度和全年降水量;标定期和验证期Hydrus-1D模型的决定系数分别为0.65～0.68,0.57～0.65;近56 a冬小麦平均蒸腾量为(176±29) mm,土壤蒸发量为(296±28) mm占降水量的60%～80%,渗漏量一般小于40 mm,土壤含水量变化为(-2±45) mm。综上,研究地70 a冬小麦产量呈上升趋势,且受年际气候变化的影响其产量波动较大。Hydrus-1D模型能够较好地模拟晋南旱塬冬小麦田的水文变化情况,多年来研究地冬小麦田土壤含水量呈下降趋势。     

Impact of climate change on soil erosion, runoff, and wheat productivity in central Oklahoma

The potential for global climate changes to increase the risk of soil erosion is clear, but the actual damage is not. The objectives of this study were to evaluate the potential impacts of climate change on soil erosion, surface runoff, and wheat productivity in central Oklahoma. Monthly projections were used from the Hadley Centre's general circulation model, HadCM3, using scenarios A2a, B2a, and GGa1 for the periods of 1950–1999 and 2070–2099. Projected changes in monthly precipitation and temperature distributions between the two periods were incorporated into daily weather series by means of a stochastic weather generator (CLIGEN) with its input parameters adjusted to each scenario. The Water Erosion Prediction Project (WEPP) model was run for four climate scenarios including a recent historical climate and three tillage systems (conventional tillage, conservation tillage, and no-till). HadCM3-projected mean annual precipitation during 2070–2099 at El Reno, Oklahoma decreased by 13.6%, 7.2%, and 6.2% for A2a, B2a, and GGa1, respectively; and mean annual temperature increased by 5.7, 4.0, and 4.7 °C, respectively. Predicted average annual soil loss in the tillage systems other than no-till, compared with historical climate (1950–1999), increased by 18–30% for A2a, remained similar for B2a, and increased by 67–82% for GGa1. Predicted soil loss in no-till did not increase in the three scenarios. Predicted mean annual runoff in all three tillage systems increased by 16–25% for A2a, remained similar for B2a, and increased by 6–19% for GGa1. The greater increases in soil loss and runoff in GGa1 were attributed to greater variability in monthly precipitation as projected by HadCM3. The increased variability led to increased frequency of large storms. Small changes in wheat yield, which ranged from a 5% decrease in B2a to a 5% increase in GGa1, were because the adverse effects of the temperature increase on winter wheat growth were largely offset by CO₂ rise as well as the bulky decrease in precipitation occurred outside the growing season. The overall results indicate that no-till and conservation tillage systems will be effective in combating soil erosion under projected climates in central Oklahoma.     

气候变化对黄河中游河龙区间径流量的影响分析

通过对黄河中游河龙区间的气候变化分析发现,河龙区间年平均气温和四季气温均呈现上升趋势;进入20世纪90年代后河龙区间年平均降水量呈明显减少趋势;春、冬季降水量呈微弱增加趋势,夏、秋季降水量呈明显减少趋势.同时计算分析了龙门站径流量对气候变化的敏感性及气候变化对径流量的影响程度.结果表明,年径流量随降水的增加而增加,随气温的升高而减少;径流量对降水变化的响应较其对气温变化的响应更为显著;20世纪90年代后,气候变化对径流量的影响幅度为21%.     

Runoff Trends Driven by Climate and Afforestation in a Pyrenean Basin

The abandonment of traditional rural life in mountain areas has favoured the expansion of forest in the headwaters of Pyrenean rivers. In this paper, we (i) analyse hydro‐climatic trends at the annual and monthly scales in three nested sub‐catchments in a central Pyrenean basin and (ii) quantify the relative contribution of climate change and forest cover on the observed changes in runoff. Land use maps indicate an increase in the forest cover in all sub‐basins for the period 1987–2009. Non‐parametric Mann–Kendall statistic on annual and monthly hydro‐climatic data from 1965 to 2009 was used to identify trends in climate and runoff data. To assess the potential influence of the period length, trends were also examined for the 1941–2009 stretch. Upward trends were detected for temperature and potential evapotranspiration, particularly during summer and winter months. Precipitation trends and their significance depended on the length of the period considered, although overall results indicated a decrease, particularly for February and July. The effects of climate change and land cover change on annual runoff were identified by means of a change point analysis. Results indicated that a change in annual runoff took place in the 1980s, suggesting the non‐linearity in the relationship between precipitation and runoff, and thus the influence of land use factors. The influence of forest cover was confirmed by comparing observed runoff trends with those resulting from a hydro‐climatic model that does not take into account land use changes. Divergence between both trends revealed that forest cover can account for ~40% of the observed decrease in annual runoff. Copyright © 2015 John Wiley & Sons, Ltd.