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1.
The study used a daily step conceptual hydrological model to examine the effects of climate change on snowfall accumulation and on snow cover melting in the Broye catchment (moderate relief- altitude from 400 to 1500 m a.s.l.). Five elevation bands representing a range of climatic conditions were used together with three realistic climate change scenarios based loosely on GCM's predictions and which reflect feasible changes by extending time periods. For a very moderate climate change (rise in air temperature of ca 1 °C), possibly in a near future, the reduction of snow cover duration, mean water equivalent and monthly maximum water equivalent is the most sensitive in the lower part of the catchment and during the first and last months of the snow season. In the higher part of the basin and during the colder months January and February, similar reduction rates can be expected in case of larger climate changes. The floods due to the melting of snow cover are lower. Sometimes rainfall, considered as snow in the present day conditions, generates additional floods during the winter season. For winter sports resorts below 1500 m a.s.l., even the very moderate climatic change scenario (temperature rise around 1 °C) leads to economically very difficult conditions. Finally, a climatic change detection index based on snow cover duration is proposed. 相似文献
2.
Although representation of hydrology is included in all regional climate models (RCMs), the utility of hydrological results from RCMs varies considerably from model to model. Studies to evaluate and compare the hydrological components of a suite of RCMs and their use in assessing hydrological impacts from future climate change were carried out over Europe. This included using different methods to transfer RCM runoff directly to river discharge and coupling different RCMs to offline hydrological models using different methods to transfer the climate change signal between models. The work focused on drainage areas to the Baltic Basin, the Bothnian Bay Basin and the Rhine Basin. A total of 20 anthropogenic climate change scenario simulations from 11 different RCMs were used. One conclusion is that choice of GCM (global climate model) has a larger impact on projected hydrological change than either selection of emissions scenario or RCM used for downscaling. 相似文献
3.
Hydrologic Sensitivity of Global Rivers to Climate Change 总被引：12，自引：1，他引：12
Bart Nijssen Greg M. O'Donnell Alan F. Hamlet Dennis P. Lettenmaier 《Climatic change》2001,50(1-2):143-175
Climate predictions from four state-of-the-art general circulation models (GCMs) were used to assess the hydrologic sensitivity to climate change of nine large, continental river basins (Amazon, Amur, Mackenzie, Mekong, Mississippi, Severnaya Dvina, Xi, Yellow, Yenisei). The four climate models (HCCPR-CM2, HCCPR-CM3, MPI-ECHAM4, and DOE-PCM3) all predicted transient climate response to changing greenhouse gas concentrations, and incorporated modern land surface parameterizations. Model-predicted monthly average precipitation and temperature changes were downscaled to the river basin level using model increments (transient minus control) to adjust for GCM bias. The variable infiltration capacity (VIC) macroscale hydrological model (MHM) was used to calculate the corresponding changes in hydrologic fluxes (especially streamflow and evapotranspiration) and moisture storages. Hydrologic model simulations were performed for decades centered on 2025 and 2045. In addition, a sensitivity study was performed in which temperature and precipitation were increased independently by 2 °C and 10%, respectively, during each of four seasons. All GCMs predict a warming for all nine basins, with the greatest warming predicted to occur during the winter months in the highest latitudes. Precipitation generally increases, but the monthly precipitation signal varies more between the models than does temperature. The largest changes in the hydrological cycle are predicted for the snow-dominated basins of mid to higher latitudes. This results in part from the greater amount of warming predicted for these regions, but more importantly, because of the important role of snow in the water balance. Because the snow pack integrates the effects of climate change over a period of months, the largest changes occur in early to mid spring when snow melt occurs. The climate change responses are somewhat different for the coldest snow dominated basins than for those with more transitional snow regimes. In the coldest basins, the response to warming is an increase of the spring streamflow peak, whereas for the transitional basins spring runoff decreases. Instead, the transitional basins have large increases in winter streamflows. The hydrological response of most tropical and mid-latitude basins to the warmer and somewhat wetter conditions predicted by the GCMs is a reduction in annual streamflow, although again, considerable disagreement exists among the different GCMs. In contrast, for the high-latitude basins increases in annual flow volume are predicted in most cases. 相似文献
4.
Summary Efforts to understand and simulate the global climate in numerical models have led to regional studies of the energy and
water balance. The Baltic Basin provides a continental scale test basin where meteorology, oceanography and hydrology all
can meet. Using a simple conceptual approach, a large-scale hydrological model of the water balance of the total Baltic Sea
Drainage Basin (HBV-Baltic) was used to simulate the basinwide water balance components for the present climate and to evaluate
the land surface components of atmospheric climate models. It has been used extensively in co-operative BALTEX (The Baltic
Sea Experiment) research and within SWECLIM (Swedish Regional Climate Modelling Programme) to support continued regional climate
model development. This helps to identify inconsistencies in both meteorological and hydrological models. One result is that
compensating errors are evident in the snow routines of the atmospheric models studied. The use of HBV-Baltic has greatly
improved the dialogue between hydrological and meteorological modellers within the Baltic Basin research community. It is
concluded that conceptual hydrological models, although far from being complete, play an important role in the realm of continental
scale hydrological modelling. Atmospheric models benefit from the experience of hydrological modellers in developing simpler,
yet more effective land surface parameterisations. This basic modelling tool for simulating the large-scale water balance
of the Baltic Sea drainage basin is the only existing hydrological model that covers the entire basin and will continue to
be used until more detailed models can be successfully applied at this scale.
Received November 24, 2000 Revised April 4, 2001 相似文献
5.
Christiana Photiadou Bart van den Hurk Aarnout van Delden Albrecht Weerts 《Climate Dynamics》2016,46(1-2):187-203
An adapted statistical bias correction method is introduced to incorporate circulation-dependence of the model precipitation bias, and its influence on estimated discharges for the Rhine basin is analyzed for a historical period. The bias correction method is tailored to time scales relevant to flooding events in the basin. Large-scale circulation patterns (CPs) are obtained through Maximum Covariance Analysis using reanalysis sea level pressure and high-resolution precipitation observations. A bias correction using these CPs is applied to winter and summer separately, acknowledging the seasonal variability of the circulation regimes in North Europe and their correlation with regional precipitation rates over the Rhine basin. Two different climate model ensemble outputs are explored: ESSENCE and CMIP5. The results of the CP-method are then compared to observations and uncorrected model outputs. Results from a simple bias correction based on a delta factor (NoCP-method) are also used for comparison. For both summer and winter, the CP-method offers a statistically significant improvement of precipitation statistics for subsets of data dominated by particular circulation regimes, demonstrating the circulation-dependence of the precipitation bias. Uncorrected, CP and NoCP corrected model outputs were used as forcing to a hydrological model to simulate river discharges. The CP-method leads to a larger improvement in simulated discharge in the Alpine area in winter than in summer due to a stronger dependence of Rhine precipitation on atmospheric circulation in winter. However, the NoCP-method, in comparison to the CP-method, improves the discharge estimations over the entire Rhine basin. 相似文献
6.
By 2025, it is estimated that around 5 billion people, out of a total population of around 8 billion, will be living in countries experiencing water stress (using more than 20% of their available resources). Climate change has the potential to impose additional pressures in some regions. This paper describes an assessment of the implications of climate change for global hydrological regimes and water resources. It uses climate change scenarios developed from Hadley Centre climate simulations (HadCM2 and HadCM3), and simulates global river flows at a spatial resolution of 0.5×0.5° using a macro-scale hydrological model. Changes in national water resources are calculated, including both internally generated runoff and upstream imports, and compared with national water use estimates developed for the United Nations Comprehensive Assessment of the Freshwater Resources of the World. Although there is variation between scenarios, the results suggest that average annual runoff will increase in high latitudes, in equatorial Africa and Asia, and southeast Asia, and will decrease in mid-latitudes and most subtropical regions. The HadCM3 scenario produces changes in runoff which are often similar to those from the HadCM2 scenarios — but there are important regional differences. The rise in temperature associated with climate change leads to a general reduction in the proportion of precipitation falling as snow, and a consequent reduction in many areas in the duration of snow cover. This has implications for the timing of streamflow in such regions, with a shift from spring snow melt to winter runoff. Under the HadCM2 ensemble mean scenario, the number of people living in countries with water stress would increase by 53 million by 2025 (relative to those who would be affected in the absence of climate change). Under the HadCM3 scenario, the number of people living in countries with water stress would rise by 113 million. However, by 2050 there would be a net reduction in populations in stressed countries under HadCM2 (of around 69 million), but an increase of 56 million under HadCM3. The study also showed that different indications of the impact of climate change on water resource stresses could be obtained using different projections of future water use. The paper emphasises the large range between estimates of “impact”, and also discusses the problems associated with the scale of analysis and the definition of indices of water resource impact. 相似文献
7.
Warmer climate: less or more snow? 总被引：1，自引：0，他引：1
Jouni Räisänen 《Climate Dynamics》2008,30(2-3):307-319
Changes in snow amount, as measured by the water equivalent of the snow pack (SWE), are studied using simulations of 21st century climate by 20 global climate models. Although the simulated warming makes snow season to shorten from its both ends in all of Eurasia and North America, SWE at the height of the winter generally increases in the coldest areas. Elsewhere, snow decreases throughout the winter. The average borderline between increasing and decreasing midwinter SWE coincides broadly with the ?20°C isotherm in late 20th century November–March mean temperature, although with some variability between different areas. On the colder side of this isotherm, an increase in total precipitation generally dominates over reduced fraction of solid precipitation and more efficient melting, and SWE therefore increases. On the warmer side, where the phase of winter precipitation and snowmelt are more sensitive to the simulated warming, the reverse happens. The strong temperature dependence of the simulated SWE changes suggests that projections of SWE change could be potentially improved by taking into account biases in simulated present-day winter temperatures. A probabilistic cross verification exercise supports this suggestion. 相似文献
8.
改进的CLDAS降水驱动对中国区域积雪模拟的影响评估 总被引：4，自引：3，他引：1
积雪因为其特定的属性在气候变化和水文循环中扮演着重要角色,在大气和陆面之间起到了调节能量和水交换的显著作用,而陆面驱动数据的质量直接决定着模式对积雪的模拟效果。本文采用CLDAS(CMA Land Data Assimilation System)和改进后的降水驱动(CLDAS-Prcp)分别驱动Noah3.6陆面模式对积雪变量进行模拟,并对中国主要的积雪区东北区域、新疆区域、青藏高原区域的积雪覆盖率、雪深、雪水当量的模拟效果进行了评估。结果表明,CLDAS-Prcp改善了原有驱动在冬季由于低估降水所造成的模拟积雪量偏少的情况;东北区域模拟结果与观测的时间变率最为一致,积雪覆盖率、雪深、雪水当量的相关系数分别为0.42,0.78,0.93;而雪水当量的改进效果最明显,均方根误差和偏差分别减小了54.8%和83.1%,相关系数提高了0.47;同时,CLDAS-Prcp不仅能反映积雪变量的年际变率,而且能够较准确地反映出强度较大的突发降雪事件。 相似文献
9.
Summary The land surface model SEWAB (Surface Energy and Water Balance) is designed to be coupled to both, atmospheric and hydrological
models. Its application in mid and high latitudes requires the inclusion of freezing and thawing processes within the soil
and the accumulation and ablation of a snow cover. These winter processes are parameterised with a minimum number of empirical
formulations in order to assure reasonable computation times for an application in climate and sensitivity studies yet accounting
for all important processes. Meteorological forcing data and measurements of snow depth, soil temperature and liquid soil
water content at two locations in the mid-west of North America are used to test the model. Generally the simulated snow depth
matches the measurements, remaining differences in snow depth can be explained by uncertainties in snow density, blowing snow
and errors in precipitation measurements. The simulated soil temperature and liquid soil water content compare well with the
measurements, showing the isolating effect of the snow cover.
Received August 25, 2000 Revised January 19, 2001 相似文献
10.
Arctic environments are generally believed to be highly sensitive to human-induced climatic change. In this paper, we explore the impacts on the hydrological system of the sub-arctic Tana Basin in Northernmost Finland and Norway. In contrast with previous studies, attention is not only given to river discharge, but also to the spatial patterns in snow coverage and evapotranspiration. We used a distributed water balance model that was coupled to a regional climate model in order to calculate a scenario of climate change by the end of this century. Three different model experiments were performed, adopting different approaches to using the climate model output in the hydrological model runs. The results were largely consistent, indicating a much shorter snow season and, accordingly, decreased sublimation, an increase in evapotranspiration, and a shift in the annual runoff peak. As the snow-free season is extended, the amount of solar radiation that is received during this period increases significantly. The results also show important local differences in the hydrological response to climate change. For example, in the scenario runs, the snow season was more than 30 days shorter at higher elevations, but in some of the river valleys, this was up to 70 days. 相似文献
11.
本文利用2000年3月-2011年2月西藏地区的MODIS雪盖产品数据、DEM数据以及地面气象观测数据,结合GIS空间分析方法,分析了西藏地区不同自然区划地带下雪线的时空变化特征及其与气象因素的关系。研究表明：西藏及各区域年平均雪线波动变化比较平稳,全区年平均雪线为4848.6m,呈微弱上升趋势,线性倾向率为6.54m/10a;各季节平均雪线中,秋季雪线的变化对年平均贡献最大,二者相关系数达0.796。冬季雪线呈下降趋势（相关系数为-0.625）,其余三季则均表现为上升趋势,但均不显著;除东喜马拉雅南翼山地雪线逐月变化波动明显外（标准差为60.3m）,其余均表现为平缓波动形势;西藏地区的雪线空间分布基本上表现为由东南向西北方向逐步升高的态势,其中东南部和西北部雪线分布密集且复杂。中部雪线则相对较稀疏,其高、低值区分别与山脉和河谷分布相对应;整体上,西藏雪线与气温正相关,与降水量负相关,但是各区域四季雪线与气温、降水量之间又存在差异。雪线是积雪各要素特征变化最为敏感的指示器,研究西藏高原雪线的时空分布特征及其与气象因素之间的关系,对了解西藏高原乃至整个青藏高原的气候变化具有重要的意义。 相似文献
12.
Brazilian strategic interest in the Madeira River basin, one of the most important of the southern Amazon tributaries, includes the development of hydropower to satisfy the country’s growing energy needs and new waterways to boost regional trade and economic development. Because of evidences that climate change impacts the hydrological regime of rivers, the aim of this study was to assess how global climate change and regional land cover change caused by deforestation could affect the river’s hydrological regime. To achieve this goal, we calibrated a large-scale hydrological model for the period from 1970–1990 and analyzed the ability of the model to simulate the present hydrological regime when climate model simulations were used as input. Climate change projections produced by climate models were used in the hydrological model to generate scenarios with and without regional land-use and land-cover changes induced by forest conversion to pasture for the period from 2011–2099. Although results show variability among models, consensus scenarios indicated a decrease in the low-flow regime. When the simulations included forest conversion to pasture, climate change impacts on low flows were reduced in the upper basin, while, in the lower basin, discharges were affected along the whole year due to the more vigorous land-use conversion in the Brazilian region of the basin. 相似文献
13.
ABSTRACTIn situ observations of snow water equivalent (SWE) from manual snow surveys and automated sensors are made at approximately 1000 sites across Canada in support of water resource planning for flood control and hydroelectricity production. These data represent an important source of information for research (e.g., validation of hydrological and climate models), for applied studies (e.g., ground snow loads), and for climate monitoring. This note describes the process to update a Canadian historical snow survey dataset to 2016 and the production of a 0.1° gridded version for research applications. Analysis of trends in SWE, snow depth (SD), and density over the 50-year period from 1967 to 2016 revealed large spatial variability in trend sign and strength, with a relatively small percentage of points showing statistically significant trends. Where SWE and SD trends were significant, they tended to be negative, which is consistent with previous investigations of snow cover changes in Canada. The results show evidence of a latitudinal dependence in SWE trends, with the largest negative trends occurring over lower latitudes, and a tendency for mainly positive trends in Arctic SWE, which is consistent with observations from Russia and climate model projections of the response of Arctic snow cover to climate warming. Arctic sites also showed evidence of an increasing trend in 1 April snowpack density of 6.6?kg m?3 per decade but little corresponding change in SD. This has potentially important consequences for the soil thermal regime because it provides a cooling influence from an increase in the snowpack effective thermal conductivity. The snow survey dataset is available from the Government of Canada Open Data portal. 相似文献
14.
River discharge and freshwater runoff to the Barents Sea under present and future climate conditions
River discharge forms a major freshwater input into the Arctic Ocean, and as such it has the potential to influence the oceanic
circulation. As the hydrology of Arctic river basins is dominated by cryospheric processes such as snow accumulation and snowmelt,
it may also be highly sensitive to a change in climate. Estimating the water balance of these river basins is therefore important,
but it is complicated by the sparseness of observations and the large uncertainties related to the measurement of snowfalls.
This study aims at simulating the water balance of the Barents Sea drainage basin in Northern Europe under present and future
climate conditions. We used a regional climate model to drive a large-scale hydrological model of the area. Using simulated
precipitation derived from a climate model led to an overestimation of the annual discharge in most river basins, but not
in all. Under the B2 scenario of climate change, the model simulated a 25% increase in freshwater runoff, which is proportionally
larger than the projected precipitation increase. As the snow season is 30–50 day shorter, the spring discharge peak is shifted
by about 2–3 weeks, but the hydrological regime of the rivers remains dominated by snowmelt. 相似文献
15.
Stefan Hagemann Holger Göttel Daniela Jacob Philip Lorenz Erich Roeckner 《Climate Dynamics》2009,32(6):767-781
For the fourth assessment report of the Intergovernmental Panel on Climate Change (IPCC), the recent version of the coupled
atmosphere/ocean general circulation model (GCM) of the Max Planck Institute for Meteorology has been used to conduct an ensemble
of transient climate simulations These simulations comprise three control simulations for the past century covering the period
1860–2000, and nine simulations for the future climate (2001–2100) using greenhouse gas (GHG) and aerosol concentrations according
to the three IPCC scenarios B1, A1B and A2. For each scenario three simulations were performed. The global simulations were
dynamically downscaled over Europe using the regional climate model (RCM) REMO at 0.44° horizontal resolution (about 50 km),
whereas the physics packages of the GCM and RCM largely agree. The regional simulations comprise the three control simulations
(1950–2000), the three A1B simulations and one simulation for B1 as well as for A2 (2001–2100). In our study we concentrate
on the climate change signals in the hydrological cycle and the 2 m temperature by comparing the mean projected climate at
the end of the twenty-first century (2071–2100) to a control period representing current climate (1961–1990). The robustness
of the climate change signal projected by the GCM and RCM is analysed focussing on the large European catchments of Baltic
Sea (land only), Danube and Rhine. In this respect, a robust climate change signal designates a projected change that sticks
out of the noise of natural climate variability. Catchments and seasons are identified where the climate change signal in
the components of the hydrological cycle is robust, and where this signal has a larger uncertainty. Notable differences in
the robustness of the climate change signals between the GCM and RCM simulations are related to a stronger warming projected
by the GCM in the winter over the Baltic Sea catchment and in the summer over the Danube and Rhine catchments. Our results
indicate that the main explanation for these differences is that the finer resolution of the RCM leads to a better representation
of local scale processes at the surface that feed back to the atmosphere, i.e. an improved representation of the land sea
contrast and related moisture transport processes over the Baltic Sea catchment, and an improved representation of soil moisture
feedbacks to the atmosphere over the Danube and Rhine catchments. 相似文献
16.
Jaak Jaagus 《Climatic change》1997,36(1-2):65-77
The paper deals with problems of temporal and spatial variability of snow cover duration, of correlation between snow cover and winter mean air temperature patterns and of the impact of climate change on the snow cover pattern in Estonia. Snow cover fields are presented in form of IDRISI raster images. Snow cover duration measured at ca 100 stations and observation points have been interpolated into raster cells. On the base of time series of raster images, a map of mean territorial distribution of snow cover duration is calculated. Estonia is characterized by a great spatial variability of snow cover mostly caused by the influence of the Baltic Sea. General regularities of snow cover pattern are determined. A 104-year time series of spatial mean values of snow cover duration is composed and analyzed. A decreasing trend and periodical fluctuations have detected. Standardized principal component analysis is used for the time series of IDRISI raster images. It enables to study the influence of different factors on the formation of snow cover fields and territorial extent of coherent fluctuations. Correlation between snow cover duration and winter mean air temperature fields is analyzed. A spatial regression model is created for estimation of the influence of climate change on snow cover pattern in Estonia. Using incremental climate change scenarios (2 °C, 4 °C and 6 °C of warming in winter) mean decrease of snow cover duration in different regions in Estonia is calculated. According to results of model calculation, the highest decrease of snow cover duration will be take place on islands and in the coastal region of West Estonia. A permanent snow cover may not form at all. In the areas with maximum snow cover duration in North-East and South-East Estonia, that decrease should be much lower. 相似文献
17.
利用MODIS积雪资料以及同期气象资料,分析了2000—2009年玛纳斯河流域积雪面积年内、年际变化及其与同期气温和降水的关系,结果表明:玛纳斯河流域积雪面积在4个不同分带上随季节变化各不相同,其中,带1变化最剧烈,受气候影响最为显著;带2、带3积雪的增加和减少都比较平缓;带4受气候影响最小。从年际波动来看,带1积雪面积随季节变化更为明显,带4在四季变化中均较平稳。对整个流域积雪面积与气候资料的相关分析表明:冬季,流域积雪变化对降水更敏感;而春季,气温是影响流域积雪面积变化的更主要的因素。 相似文献
18.
This paper investigates how using different regional climate model (RCM) simulations affects climate change impacts on hydrology in northern Europe using an offline hydrological model. Climate change scenarios from an ensemble of seven RCMs, two global climate models (GCMs), two global emissions scenarios and two RCMs of varying resolution were used. A total of 15 climate change simulations were included in studies on the Lule River basin in Northern Sweden. Two different approaches to transfer climate change from the RCMs to hydrological models were tested. A rudimentary estimate of change in hydropower potential on the Lule River due to climate change was also made. The results indicate an overall increase in river flow, earlier spring peak flows and an increase in hydropower potential. The two approaches for transferring the signal of climate change to the hydrological impacts model gave similar mean results, but considerably different seasonal dynamics, a result that is highly relevant for other types of climate change impacts studies. 相似文献
19.
利用MODIS积雪资料以及同期气象资料,分析了2000-2009年玛纳斯河流域积雪面积年内、年际变化及其与同期气温和降水的关系,结果表明:玛纳斯河流域积雪面积在4个不同分带上随季节变化各不相同,其中,带1变化最剧烈,受气候影响最为显著;带2、带3积雪的增加和减少都比较平缓;带4受气候影响最小.从年际波动来看,带1积雪面积随季节变化更为明显,带4在四季变化中均较平稳.对整个流域积雪面积与气候资料的相关分析表明:冬季,流域积雪变化对降水更敏感;而春季,气温是影响流域积雪面积变化的更主要的因素. 相似文献
20.
政府间气候变化专门委员会（IPCC）于2008年4月8日正式通过了"气候变化和水"技术报告。该报告建立在IPCC 3个工作组第四次评估报告的基础上,客观、全面而审慎地评估了与水有关的气候变化以及对水的过去、现在和未来的认知。最重要的进展是：过去几十年观测到全球变暖已经与大尺度水文循环的大规模变化联系在一起;气候模型对21世纪的模拟结果一致显示出降水在高纬和部分热带地区将增加,而在部分亚热带和中低纬地区将减少的结果;预计到21世纪中期,河流年平均径流和水量可能会因为高纬和部分湿润热带地区的气候变化而增加,而在中低纬和干旱热带将可能减少;许多地方降水强度和变率的增加将使洪旱危险性上升;预计冰雪储藏的水的补给将在本世纪减少;预计较高的水温和极端变化,包括洪旱等,将影响水质并加剧水污染;对全球而言,气候变化对淡水系统负面影响将超过收益;预计由于气候变化导致的水量-水质变化将影响食物的产量、稳定性、流通和利用;气候变化影响现有水的基础设施的功能和运行,包括水电、防洪、排水、灌溉系统,同时影响到水的管理;目前的水管理措施不足以应对气候变化的影响;气候变化挑战"过去水文上的经验能得到未来的情况"的传统说法;为保障平水和干旱情况所设计的适应选择,必须综合需水和供水双方的战略;减缓措施可以降低升温对全球水资源的影响程度,进而减低适应的需求;水资源管理明显地影响到很多其他政策领域。 相似文献