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1.
Safavi Hamid R. Sajjadi Sayed Mahdi Raghibi Vahid 《Theoretical and Applied Climatology》2017,130(1-2):635-653
Water resources in snow-dependent regions have undergone significant changes due to climate change. Snow measurements in these regions have revealed alarming declines in snowfall over the past few years. The Zayandeh-Rud River in central Iran chiefly depends on winter falls as snow for supplying water from wet regions in high Zagrous Mountains to the downstream, (semi-)arid, low-lying lands. In this study, the historical records (baseline: 1971–2000) of climate variables (temperature and precipitation) in the wet region were chosen to construct a probabilistic ensemble model using 15 GCMs in order to forecast future trends and changes while the Long Ashton Research Station Weather Generator (LARS-WG) was utilized to project climate variables under two A2 and B1 scenarios to a future period (2015–2044). Since future snow water equivalent (SWE) forecasts by GCMs were not available for the study area, an artificial neural network (ANN) was implemented to build a relationship between climate variables and snow water equivalent for the baseline period to estimate future snowfall amounts. As a last step, homogeneity and trend tests were performed to evaluate the robustness of the data series and changes were examined to detect past and future variations. Results indicate different characteristics of the climate variables at upstream stations. A shift is observed in the type of precipitation from snow to rain as well as in its quantities across the subregions. The key role in these shifts and the subsequent side effects such as water losses is played by temperature.
相似文献2.
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
3.
This work analyzes the consequences of climate change in the distribution of the Mediterranean high-mountain vegetation. A study area was chosen at the Sierra de Guadarrama, in the center of the Iberian Peninsula (1,795 to 2,374 m asl). Climate change was analyzed from the record of 18 variables regarding temperature, rainfall and snowfall over the period 1951–2000. The permanence of snow cover (1996–2004), landforms stability and vegetation distribution in 5 years (1956, 1972, 1984, 1991 and 1998) were all analyzed. The Nival Correlation Level of the different vegetation classes was determined through their spatial and/or temporal relationship with several climatologic variables, snow cover duration and landforms. In order to quantify trends and major change processes, areas and percent changes were calculated, as well as Mean Annual Transformation Indices and Transition Matrices. The findings reveal that in the first part of the study period (up to the first half of the 1970s) the temperature rise in the mid-winter months caused the reduction of some classes of nival vegetation, while others expanded, favored by high rainfall, decrease in both maximum temperatures and summer aridity, and longer snow cover duration. The second part of the study period was characterized by the consolidation of the increase in all thermal variables, along with an important reduction in rainfall volume and snow cover duration. As a result, herbaceous plants, which are highly correlated with a long snow permanence and abundance of melting water, have been replaced by leguminous shrubs which grow away from the influence of snow, and which are steadily becoming denser. 相似文献
4.
利用1961-2005年青海南部牧区气象台站观测的气温、降水、积雪资料,用气候诊断方法分析了该地区积雪等气候要素的年代际演变特征以及雪灾变化的成因。结果表明：20世纪60-90年代冬季青海南部牧区中雪和大雪出现的站次以及雪灾出现的站次有逐步增多的趋势,降雪量和地表平均积雪量每10 a分别增加1. 253 mm和8.246 cm,单站积雪量在海拔4100 m左右的高度上增加比较明显,其变化是由气候的年代际波动引起的。 相似文献
5.
Results from four snow models-two used in climate models, one being developed for hydrological forecasting and one used for
avalanche forecasting-are compared with observations made during two contrasting winters at a site in the French Alps. The
models are all driven with hourly measurements of air temperature, windspeed, humidity, snowfall and downward longwave and
shortwave radiation, but they differ greatly in complexity. Results from the models are compared with measurements of snowdepth,
snow water equivalent, surface temperature, runoff and albedo. The models all represent the duration of snow cover well, but
differ in their predictions of peak accumulation and timing of runoff. Experience gained in this study is used to make recommendations
for a more ambitious intercomparison between a larger number of models for a wide range of environments.
Received: 31 July 1998 / Accepted: 12 February 1999 相似文献
6.
G. Diolaiuti D. Bocchiola C. D’agata C. Smiraglia 《Theoretical and Applied Climatology》2012,109(3-4):429-445
We present evidence of climate change impact upon recent changes of glaciers within Lombardy region, in Northern Italy. We illustrate the recent area evolution of a set of 249 glaciers in the area using three surface area records for 1991, 1999 and 2003. The 1999 and 2003 surface area data are processed by combining glacier limits manually digitized upon registered color orthophotos and differential GPS (DGPS) glaciers’ surveys. Glaciers’ area was 117.4?km2 in 1991, 104.7?km2 in 1999, and to 92.4?km2 2003, with a 21% reduction. Glaciers smaller than 1?km2 accounted for 53% of the total loss in area (13.1?km2 during 1991–2003). The area change rate was higher lately, with ca. 11.7 % reduction during 1999–2003. We split Alps and fore Alps of Lombardy into six mountain groups, and we separately investigate relative area variations. We use climate series from local stations within each group to assess climate change during a 30-year window (1976–2005). We focus upon temperature and snow cover depth at thaw, known to impact glaciers’ changes. We compare local year-round temperature anomalies against global ones to evidence enhanced warming within this area, and we investigate the correlation of our target climate variables against NAO. Eventually, we highlight the link between the rate of change of our climate variables to the observed scaling of area loss against glaciers’ size, showing that in rapidly warming areas glaciers’ size affects less relative melting. 相似文献
7.
利用冬奥会气象观测站网资料、ERA5的0.25°×0.25°高分辨率再分析资料、常规探空资料以及激光雷达和风廓线雷达资料,从环流形势、温湿度和微物理特征以及雷达特征等方面对2020年11月17-19日冬奥会张家口赛区一次明显的雨转雪天气过程进行分析。结果表明：低层前期的暖湿西南气流,为降水提供好的水汽和能量条件,后期强的干冷平流为相态转换提供有利条件。赛区出现雨转雪时,700 hPa温度低于-2℃,同时850 hPa温度低于2℃。零度层高度的快速下降是相态转换的重要温度判据,0℃线降到距地面400 m左右赛区降水相态已经转变为纯雪,低层风向的转向对赛场的雨雪相态转换有一定的指示意义。随着高空云冰和雪水含量逐渐增加,其出现最大值后,雨雪相态开始转换。降雪时激光雷达最大探测高度比降雨时有明显的降低,风廓线雷达低层风场的变化和雨雪相态关系密切,风廓线雷达探测的垂直速度变化也能反映雨雪相态的转换。 相似文献
8.
利用青藏高原气象站降雪日数观测资料,分析1981-2010年青藏高原降雪日数的时空变化特点和主要影响因素。结果表明:降雪日数总体上呈青藏高原中东部高寒地区、喜马拉雅山脉南麓和祁连山脉流域降雪日数多,南部河谷和北部湖盆区降雪日数少的空间分布格局;春季降雪日数占全年的45%,其次是冬季（28%）和秋季（22%）,夏季最少（5%）;30年内青藏高原平均年降雪日数呈明显减少趋势,降幅达10.5 d/（10 a）,其中,春季降幅最大（4.8 d/（10 a））,夏季最小（1.2 d/（10 a））;年降雪日数在1997年发生了由多到少的气候突变;降雪日数年内分布呈双峰型,峰值出现在冬夏大气环流的转换季节,青藏高原大气环流的转换期与上升运动相联系的低值天气系统和高空温湿条件均有利于降雪出现;青藏高原降雪日数的明显减少与气温的显著上升呈线性关系。 相似文献
9.
Long-term variability of occurrence of precipitation forms in winter in Kraków, Poland 总被引：1，自引：0，他引：1
Robert Twardosz Ewa ?upikasza Tadeusz Nied?wied? Adam Walanus 《Climatic change》2012,113(3-4):623-638
The paper discusses long-term change in snowfall, rainfall and mixed precipitation viewed in conjunction with air temperature and North Atlantic Oscillation (NAO) in winter (December–February). In the study of contemporary climate change and its effect on the hydrological cycle it is useful to focus on winter precipitation forms. A 146-year secular observation series from Kraków, spanning the period 1863–2008, was used to extract data on the number of days with precipitation and on precipitation amount broken down by form. Statistically significant trends were found in total and mixed precipitation, but not in snowfall and rainfall. The climate warming effect has contributed to a material decrease in the snowfall to total winter precipitation ratio during the second half of the 20th c. The highest impact of air temperature was found in the wintertime variation in number of days with snowfall while the NAO had a significant influence on the frequency and amount of both rainfall and snowfall. 相似文献
10.
Bhogendra Mishra Mukand S. Babel Nitin K. Tripathi 《Theoretical and Applied Climatology》2014,116(3-4):681-694
Various remote sensing products and observed data sets were used to determine spatial and temporal trends in climatic variables and their relationship with snow cover area in the higher Himalayas, Nepal. The remote sensing techniques can detect spatial as well as temporal patterns in temperature and snow cover across the inaccessible terrain. Non-parametric methods (i.e. the Mann–Kendall method and Sen's slope) were used to identify trends in climatic variables. Increasing trends in temperature, approximately by 0.03 to 0.08 °C year?1 based on the station data in different season, and mixed trends in seasonal precipitation were found for the studied basin. The accuracy of MOD10A1 snow cover and fractional snow cover in the Kaligandaki Basin was assessed with respect to the Advanced Spaceborne Thermal Emission and Reflection Radiometer-based snow cover area. With increasing trends in winter and spring temperature and decreasing trends in precipitation, a significant negative trend in snow cover area during these seasons was also identified. Results indicate the possible impact of global warming on precipitation and snow cover area in the higher mountainous area. Similar investigations in other regions of Himalayas are warranted to further strengthen the understanding of impact of climate change on hydrology and water resources and extreme hydrologic events. 相似文献
11.
以乌鲁木齐冬季清雪工作需求为牵引,利用乌鲁木齐2006—2016年冬季(当年11月—翌年3月)逐日降雪量、积雪深度、气温和173 d降雪日的逐时降雪量资料,分析了近11年冬季各量级降雪的分布特征、降雪持续时间和降雪的日变化特征;对积雪深度和对应降雪量做线性拟合,得出二者比值大体为0.968 cm/mm。得出清雪预报服务的重点是:小雪的有无、降雪起止时间和累积降雪量、积雪深度的预报,难点是中雪、大雪特别是暴雪和对应的积雪深度的精细化预报。 相似文献
12.
Long-term snow and weather observations at Weissfluhjoch and its relation to other high-altitude observatories in the Alps 总被引：1，自引：1，他引：0
Snow and weather observations at Weissfluhjoch were initiated in 1936, when a research team set a snow stake and started digging snow pits on a plateau located at 2,540?m asl above Davos, Switzerland. This was the beginning of what is now the longest series of daily snow depth, new snow height and bi-monthly snow water equivalent measurements from a high-altitude research station. Our investigations reveal that the snow depth at Weissfluhjoch with regard to the evolution and inter-annual variability represents a good proxy for the entire Swiss Alps. In order to set the snow and weather observations from Weissfluhjoch in a broader context, this paper also shows some comparisons with measurements from five other high-altitude observatories in the European Alps. The results show a surprisingly uniform warming of 0.8°C during the last three decades at the six investigated mountain stations. The long-term snow measurements reveal no change in mid-winter, but decreasing trends (especially since the 1980s) for the solid precipitation ratio, snow fall, snow water equivalent and snow depth during the melt season due to a strong temperature increase of 2.5°C in the spring and summer months of the last three decades. 相似文献
13.
Global climate models predict that terrestrial northern high-latitude snow conditions will change substantially over the twenty-first century. Results from a Community Climate System Model simulation of twentieth and twenty-first (SRES A1B scenario) century climate show increased winter snowfall (+10–40%), altered maximum snow depth (?5 ± 6 cm), and a shortened snow-season (?14 ± 7 days in spring, +20 ± 9 days in autumn). By conducting a series of prescribed snow experiments with the Community Land Model, we isolate how trends in snowfall, snow depth, and snow-season length affect soil temperature trends. Increasing snowfall, by countering the snowpack-shallowing influence of warmer winters and shorter snow seasons, is effectively a soil warming agent, accounting for 10–30% of total soil warming at 1 m depth and ~16% of the simulated twenty-first century decline in near-surface permafrost extent. A shortening snow season enhances soil warming due to increased solar absorption whereas a shallowing snowpack mitigates soil warming due to weaker winter insulation from cold atmospheric air. Snowpack deepening has comparatively less impact due to saturation of snow insulative capacity at deeper snow depths. Snow depth and snow-season length trends tend to be positively related, but their effects on soil temperature are opposing. Consequently, on the century timescale the net change in snow state can either amplify or mitigate soil warming. Snow state changes explain less than 25% of total soil temperature change by 2100. However, for the latter half of twentieth century, snow state variations account for as much as 50–100% of total soil temperature variations. 相似文献
14.
丹东地区沿海和山区降雪气候特征 总被引：2，自引：0，他引：2
利用丹东地区4个观测站1955—2010年逐年10月至翌年4月逐日降水量、天气现象、雪深等资料,对丹东地区南部沿海和北部山区降雪气候特征进行了分析,结果表明:丹东地区沿海和山区降雪初日、终日及初终日间隔日数、年降雪日数、年降雪量、降水相态、日最大降雪量、日最大积雪深度等平均特征不同。与山区相比,沿海降雪初期较晚,终期较早,初、终日间日数较短,年降雪日数和年降雪量相对较少。在丹东地区1955—2010年降雪时段平均气温升高趋势显著背景下,丹东地区降雪初期推迟、终期提前、初终日间隔日数缩短;降雪日数减少,其中雨夹雪日数所占百分比显著增多;降雪量减少,其中主要是纯雪量减少;日最大降雪量和积雪深度呈减小趋势;沿海和山区变化幅度不同。 相似文献
15.
无资料地区雪灾防御参数常采用周边有资料的气象站参数替代,基于气候背景相似的降雪气候区划可以为代表站的选取提供科学依据。本文利用湖北省76个国家气象站1961—2020年的气象观测资料,选取了降雪初终日、雪日数、积雪日数、降雪量、最大积雪深度等12个多维时间序列指标,采用Hilbert-Schmidt Independence Criterion（HSIC）核函数的有偏估计公式计算12个指标的整体相似性,对湖北省降雪气候进行了聚类分析。结果表明：湖北省降雪气候可以划分为东南部、中部、西北部和西南部4个气候分区,分区的地带性分布特征与湖北省强降雪天气由北方冷空气南下产生的气候背景一致;初雪日从西北部向中部、西南部、东南部降雪区推迟,终雪日则正好相反,西北部的降雪日数和积雪日数最多;东南部代表站为黄石站,中部代表站有麻城、武汉、钟祥,西南部代表站有咸丰、巴东,西北部代表站郧西、老河口。HSIC核函数能很好处理较大年际波动的指标序列集之间的相似性,其聚类方法对湖北省降雪的气候区划较为合理,区划结果为湖北省精细化雪灾防御提供了技术依据。 相似文献
16.
基于天山山区1961-2013年60个气象站点实测气温、降水、相对湿度、日照时数和积雪深度等气候资料,结合时间序列分析、空间分析以及通径分析等方法,全面精确地获取了天山山区气候变化特征以及气候变化对积雪的通径影响。结果表明：天山山区气候变化显著,主要表现为整体增暖、局部变湿与黯化;气候变暖导致天山山区固态降水（降雪）保证率明显降低,尤其是低海拔区域。各气象要素对积雪不仅存在直接的单因素影响而且各气象要素之间还存在间接的相互交叉、相互联结的多因素影响。单因素影响通径分别为气温、降水和日照时数对积雪深度的3条直接影响通径;多因素影响通径分别为气温、降水和日照时数通过相互之间的内在关系对积雪深度产生的6条间接影响通径。最终结果表明气温是积雪变化的主要影响因素,其影响效应远远大于降水和日照时数的影响。 相似文献
17.
使用雪日直接界定法,建立了中国大陆长江以北地区（30°N以北）降水相态分离单临界气温统计模型,分东部季风区、西北干燥区和青藏高原区3个不同气候区独立样本建模,检验模型外推使用的可能性,并对单临界气温分离的雨夹雪偏差进行分析。结果表明:所有地区独立样本建立模型估算的单临界气温与根据天气现象记录确定的单临界气温相关性均达到0.05显著性水平,3个气候区独立建模能够估算出降水相态单临界气温的范围及区域特性;以东部季风区和青藏高原区为样本独立建模的估算结果好于西北干燥区;3个独立模型估算的单临界气温偏差绝对值不大于1℃的气象站都多于74%,估算的标准差偏差在-0.5~0.5℃之间的气象站数量占比77%,在-1.0~1.0℃之间的气象站数量占比90%;日平均气温低于单临界气温的雨夹雪日数和降水量与实际降雪日和降雪量的比率北部略小、南部较大,东部季风区的南部雨夹雪界定的雪日和雪量比率均超过100%;使用统计模型确定不同区域雨夹雪中界定的雪日和雪量比率分布也具有可行性。 相似文献
18.
基于全国气象台站逐日地面降雪观测数据,对我国25°N以北不同气候区强降雪事件的地理分布和年内旬、月变化等气候特征进行分析,并探讨1961—2008年其时间序列演变特征,及1961—2008年和1981—2008年 (气候变暖后) 气候变化趋势。结果表明:强降雪量和强降雪日数在青藏高原东部、新疆和东北北部最多;强降雪强度高值中心出现在云南。东北北部、华北、西北、青藏高原东部强降雪事件多发生于初冬和初春,年内分布呈双峰型;新疆和黄淮地区年内分布呈单峰型,前者多发生在隆冬时节,后者多发生于晚冬;1961—2008年东北北部、新疆、青藏高原东部平均强降雪量和强降雪日数呈明显增加趋势;气候变暖后我国大部年强降雪量增多,强降雪日数增加,强降雪强度增强。 相似文献
19.
高速公路路面干湿状态判别及积水模型应用研究 总被引：1，自引：0，他引：1
为了探明公路路面积水(积雪)过程和干湿状况的变化及其气象因子的影响,以江苏省金坛试验基地试验路段的道路气象数据作为模型输入数据,利用改进的Sass道路积水物理模型对3次降雨(雪)过程中的道路积水量进行模拟,通过对模型模拟结果的分级和与仪器记录、人工观测结果的对比,验证模型模拟路面状况的准确性,并探讨了气象因子对路面积水量的影响。研究结果表明:(1) 改进的Sass模型可用于对道路干湿状况的模拟,且准确性较高,可推广到高速公路路面状况的实时监测和预报;(2) 排水过程中,径流和蒸发在不同时期对排水量的贡献率差异较大,从总量上讲,径流对排水起了主要作用;(3) 气象因子对道路积水的影响主要体现在降水量直接影响道路积水,而其他气象因子则通过对蒸发量的影响来间接影响积水量。 相似文献
20.
Marie Piazza Julien Boé Laurent Terray Christian Pagé Emilia Sanchez-Gomez Michel Déqué 《Climatic change》2014,122(4):583-594
Snowfall changes in mountain areas in response to anthropogenic forcing could have widespread hydrological, ecological and economic impacts. In this paper, the robustness of snowfall changes over the French Alps projected during the 21st century and the associated uncertainties are studied. In particular, the role of temperature changes on snowfall changes is investigated. Those issues are tackled through the analysis of the results of a very large ensemble of high-resolution regional climate projections, obtained either through dynamical or statistical downscaling. We find that, at the beginning and at the end of the cold season extending from November to March (included), temperature change is an important source of spread in snowfall changes. However, no link is found between temperature and snowfall changes in January and February. At the beginning and at the end of the cold season, the rate of change in snowfall per Kelvin does not depend much on the bias correction step, the period or the greenhouse gas scenario but mostly on the downscaling method and the climate models, the latter uncertainty source being dominant. 相似文献