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1.
《The Professional geographer》2013,65(1):117-125
This study develops observed climate-based downscaling transfer functions that are used with general circulation model (GCM) output to assess potential global-change impacts on Upper Colorado Plateau, USA, water resources. Daily automated snow water equivalent stations are used with 700 mb atmospheric circulation to determine empirical transfer functions. Downscaling methodologies using multiple regression and neural networks are evaluated, with the neural network results explaining approximately 70%of the daily snowfall variance. The neural network-based transfer functions are used with the GENESIS GCM to simulate snowfall characteristics in both a 1xCO2 and a 2xCO2 climate. While the total precipitation simulated by the 2xCO2 analysis remains nearly the same as today, less will fall as snow; specifically, snow water equivalence shows significant reduction (except in the Green River Basin) as the snow season is reduced by 58 days on average. 相似文献
2.
Johnathan W. Sugg Christopher M. Fuhrmann L. Baker Perry Dorothy K. Hall Charles E. Konrad II 《自然地理学》2017,38(2):105-123
AbstractSnowfall in the Southern Appalachian Mountain region of the eastern US is characterized by much spatiotemporal variability. Annual snowfall totals vary by up to 75 cm, and variations in snowfall intensity can lead to large differences in the local snowfall distribution. Research has shown that the synoptic pattern associated with the snowfall strongly influences the regional-scale distribution of snow cover. However, topographic variability results in locally complex snow cover patterns that are not well understood or documented. In this study, we characterize the snow covered area (SCA) and fractional snow cover associated with different synoptic patterns in 14 individual sub-regions. We analyze 63 snow events using Moderate-resolution Imaging Spectroradiometer standard snow cover products to ascertain both qualitative and quantitative differences in snow cover across sub-regions. Among sub-regions, there is significant variation in the snow cover pattern from individual synoptic classes. Furthermore, the percent SCA follows the regional snowfall climatology, and sub-regions with the highest elevations and northerly latitudes exhibit the greatest variability. Results of the sub-regional analysis provide valuable guidance to forecasters by contributing a deeper understanding of local snow cover patterns and their relationship to synoptic-scale circulation features. 相似文献
3.
祁连山区季节性积雪资源的气候分析* 总被引：14，自引：0，他引：14
本文采用1986年10月至1988年9月NOAA—9、10两颗卫星的AVHRR资料标准化后反演的积雪参量,对照祈连山区26个气象站1951—1988年逐日雪深、雪密度和积雪日数的资科,修正卫星反演的平均值。得到高分辨率多年平均雪深和雪盖频率的空间分布。从而估算出各流域平均雪储量,并与降雪量和春季融雪径流作对此分析。 相似文献
4.
识别降雪异常空间模态,明晰降雪异常的影响因素,对理解中国南北过渡带气候变化规律具有重要的实践意义。论文基于1970—2020年逐日气象数据,辅以湿球温度动态阈值法、经验正交分解法等气候诊断方法,对秦岭南北冷季(11月—次年5月)降雪异常空间模态进行识别,探讨了不同主导模态与海气异常的相关关系。结果表明：(1)秦岭南北冷季降雪异常存在2个主导模态。第1模态为“全区一致型”,降雪异常偏强区分布于关中平原、秦岭山地、汉江谷地和大巴山区东段;第2模态为“山地主导下降型”,反映山地降雪异常对气候变化的敏感性;(2)在时间变化上,第1模态以年际波动为主,20世纪90年代中期后,空间模态多处于负相位,即全区一致降雪偏少;第2模态以年代转折为主,近期空间模态多处于正相位,即山地降雪异常偏少;(3)在影响因素上,第1模态降雪异常与1月中高纬度500 hPa欧亚遥相关波列相关,第2模态降雪异常与冬季赤道中东太平洋海温异常密切相关。研究将降雪异常格局与环流异常机制组合研究,可为理解中国南北过渡带降雪异常预警信号提供理论基础。 相似文献
5.
中国降雪气候学特征 总被引：18，自引：1，他引：17
利用逐日地面降雪观测资料,分析中国25oN以北范围内降雪量、降雪日数、雪带分布和各强度降雪的气候学特征,得到以下结论:①雪季长度与年降雪日数在东部呈纬向分布,大兴安岭北部最长(>210 d),长江以南最短(常年无雪或偶尔降雪);在西部青海省南部和西藏自治区北部最长(>300 d),滇、川、藏交界处及新疆自治区北部较长,南疆较短(<60 d)。年降雪量东南部最少,东北和西北北部较多(>30 mm),青海和西藏降雪量最多(>60 mm)。平均降雪强度江淮一带最大。②根据雪季降雪频次划分中国的雪带,东北大部、内蒙自治区东部、新疆北部、青藏高原大部、秦岭等地区为常年多雪带;长江以南的滇南、四川盆地、江浙沿海等地区为永久无雪带;其余地区为常年降雪带和偶尔降雪带。③不同区域各级降雪日数占总降雪日数的比例都是暴雪日数最少,大雪日数其次,小雪日数最多;但中雪降雪量占总降雪量的比例在东北北部、华北、西北、新疆、东南、青藏高原东部等区域仅高于小雪降雪量,而在黄-淮地区仅次于暴雪降雪量。④降雪年内分配在东北北部、西北、新疆、青藏高原东部等地区都呈双峰型,最多雪时节在早冬和晚冬、早春,隆冬时节并不是降雪最多时间,黄-淮和东南地区呈单峰型,东南地区峰值更陡。⑤总降雪日数和除暴雪外的各等级降雪日数与地理位置关系较明显,在中国东部主要随着纬度升高增加,在中国西部随海拔高度增加而增加;随着纬度升高,东部和西部的总降雪强度都减小,西部的小雪强度也减小。 相似文献
6.
利用NASA发布的2008—2015年CloudSat卫星的2B-CWC-RO、2B-CLDCLASS、2C-SNOW-PROFILE和地面气象站的观测资料，对北疆沿天山及其周边区域内21次强降雪天气降雪前和降雪期间卫星过境时云宏微观特征进行了对比分析。本文将研究区域分为了北疆沿天山西部和中部地区，分析结果表明：（1）降雪前和降雪期间的云类型以层云、积云、高层云和深对流云为主。（2）降雪前冰粒子等效半径均值分布在58.65~67.29 μm之间，冰粒子数浓度的均值在41.2~76.5 L-1之间，冰水含量的均值在25.4~135.1 mg·m-3之间，雪水含量均值在28.0~88.0 mg·m-3之间，降雪强度均值在0.08~0.36 mm·h-1之间。（3）降雪前冰粒子等效半径、冰粒子数浓度、冰水含量、雪水含量和降雪强度均值分别比降雪期间大2.9 %、6.2 %、34.4 %、36.4 %和18.7 %，且高值区主要集中在北疆沿天山西部地区。 相似文献
7.
利用1971-2015年锡林郭勒地区15个气象观测站近45 a的逐日积雪日数资料,采用滑动T检验、Mann-Kendall检验、小波分析和EOF方法对研究区的积雪日数时空变化特征进行分析。结果表明：研究期内积雪日数在1996年发生了一次由多到少的突变,且日数变化存在7 a的主周期和11 a、22 a的副周期。积雪月际变化呈单峰型的分布特征,多雪期主要集中在12~2月,少雪期分布在10月份和4月份;研究区空间分布差异性显著,总体呈东多西少、南多北少的分布格局,区内大部地区属于稳定积雪区。对积雪日数及其影响因子进行聚类分析,将研究区划分为4种类型,分别为降雪量偏少-积雪日数偏高区、降雪量-积雪日数一致偏高区、降雪量-积雪日数中值区、降雪量-积雪日数一致偏少区。该区有3种异常分布型：第一模态为全区一致偏多（少）型;第二模态为北多（少）南少（多）型;第三模态为中西部多（少）,东南部少（多）型。 相似文献
8.
新疆北部是我国降雪高频区之一,随着全球变暖降雪量呈显著增加趋势,对新疆气候产生重要影响,由于观测资料限制对该区域小时降雪研究还未开展,影响降雪精细化预报和服务能力提升。因此,利用新疆天山山区及其以北（以下称“新疆北部”）2012年11月—2021年2月50个国家气象站小时降雪观测资料,分析了冷季（11月—翌年2月）小时降雪特征,并按日降雪量从高到低挑选30个大暴雪过程分析其小时降雪特征、影响系统及典型环流配置。结果表明：（1） 阿勒泰北部、塔城盆地、伊犁河谷为降雪小时数（SHN）高频区,可达200 h·a-1以上;天山山区SHN高频区为海拔1800~2000 m的中山带,达127.3 h·a-1,2000 m以上降雪很少。（2） 北疆和天山山区小时降雪量（R）≤1.0 mm·h-1量级SHN占比分别为91.7%和91.9%,对降雪量贡献分别为70.7%和68.9%,R>1.0 mm·h-1为小时极端降雪事件,对北疆和天山山区降雪量贡献分别为29.3%和31.1%。（3） 极端暴雪过程平均SHN为25.5 h,平均降雪量为30.7 mm,雪强约为1.2 mm·h-1,大暴雪过程由长时间降雪导致,降雪持续时间是开展大暴雪研究和进行预报服务的关键点,造成大暴雪过程的影响系统主要有中亚长波槽、中亚低涡、乌拉尔山长波槽和西西伯利亚低涡（槽）,占比分别为30.0%、6.7%、13.3%和50.0%,中纬度长波槽（涡）和北方西西伯利亚低涡（槽）系统各为50.0%。 相似文献
9.
近50年青藏高原东部冬季积雪的时空变化特征 总被引：2，自引：0，他引：2
选取青藏高原东部地区1961-2010 年64 个测站的积雪数据,分析了冬季积雪日数的空间分布和年代际变化特征,结果表明：高原东部冬季积雪空间分布差异较大,巴颜喀拉山、唐古拉山和念青唐古拉山多雪且变率大,藏南谷地、川西干暖河谷地带及柴达木盆地少雪且变率小,这样的空间分布是由周边大气环流系统及复杂局地地形共同造成的;高原东部冬季积雪表现出“少—多—少”的年代际变化特征,分别在80 年代末和20 世纪末发生由少到多和由多到少的两次突变,尤其是20 世纪末的突变更为显著;降雪和气温的变化是影响积雪日数的重要因素,其中降雪的影响更为显著;80 年代末高原冬季降雪由少到多的突变是造成积雪日数发生相应变化的主要原因;20 世纪末高原冬季气温和降雪分别发生由低到高和由多到少突变,其影响叠加导致积雪日数发生了更为显著的突变。 相似文献
10.
天山巩乃斯河谷融雪期积雪物质平衡初步研究 总被引：1，自引：1，他引：1
本文利用１９９４年３月中，下旬在中间科学院天山积雪雪崩研究站（以下简称积雪站）野外观测到的部分资料，对融雪期季节性积雪的物质平衡进行初步分析，同时利用物质平衡方程对积雪日融出量进行计算。 相似文献
11.
Martin Melles Julie Brigham-Grette Olga Yu. Glushkova Pavel S. Minyuk Norbert R. Nowaczyk Hans-W. Hubberten 《Journal of Paleolimnology》2007,37(1):89-104
The ca. 13 m long sediment core PG1351, recovered in 1998 from the central part of Lake El’gygytgyn, NE Siberia, was investigated
for lithostratigraphy, water content, dry bulk density (DBD), total organic carbon (TOC), total nitrogen (TN), total sulphur
(TS) and biogenic silica (opal) contents, and for TOC stable isotope ratios (δ13CTOC). The event stratigraphy recorded in major differences in sediment composition match variations in regional summer insolation,
thus confirming a new age model for this core, which suggests that it spans the last 250 ka BP. Four depositional units of
contrasting lithological and biogeochemical composition have been distinguished, reflecting past environmental conditions
associated with relatively warm, peak warm, cold and dry, and cold but more moist climate modes. A relatively warm climate,
resulting in complete summer melt of the lake ice cover and seasonal mixing of the water column, prevailed during the Holocene
and Marine Isotope Stages (MIS) 3, 5.1, 5.3, 6.1, 6.3, 6.5, 7.1–7.3, 7.5, 8.1 and 8.3. MIS 5.5 (Eemian) was characterized
by significantly enhanced aquatic primary production and organic matter supply from the catchment, indicating peak warm conditions.
During MIS 2, 5.2, 5.4, 6.2 and 6.4 the climate was cold and dry, leading to perennial lake ice cover, little regional snowfall,
and a stagnant water body. A cold but more moist climate during MIS 4, 6.6, 7.4, 8.2 and 8.4 is thought to have produced more
snow cover on␣the perennial ice, strongly reducing light penetration and biogenic primary production in␣the lake. While the
cold–warm pattern during␣the past three glacial–interglacial cycles is probably controlled by changes in regional summer insolation,
differences in the intensity of the warm phases and in the degree of aridity (changing snowfall) during cold phases likely
were due to changes in atmospheric circulation patterns.
This is the seventh in a series of eleven papers published in this special issue dedicated to initial studies of El'gygytgyn Crater Lake and
its catchment in NE Russia. JulieBrigham-Grette, Martin Melles, Pavel Minyuk were guest editors of this special issue. 相似文献
12.
西北地区降雪和融雪特征的长期变化对于融雪洪水过程的准确模拟具有重要意义。本研究基于1961—1979年站点观测的日降水和气温等数据,首先对比了湿球温度法、KS方法和双临界气温法计算的降雪量,确定了精度最高的双临界气温方案,进而计算了1980—2019年的日雪雨比,最后分析了雪雨比、降雪开始日期和融雪开始日期的变化规律。结果包括:①春季平均气温呈显著上升趋势,随海拔上升升温速率减小,青藏高原地区、东南部半干旱区、半湿润区春季气温上升速率略低于北疆、南疆、河西走廊及内蒙古西部,春季雪雨比在海拔1000 m以上呈显著下降趋势,在青藏高原地区、东南部半干旱区、半湿润区呈显著下降趋势;秋季平均气温显著上升,随海拔上升升温速率增大,空间上在青藏高原地区上升速率最快,秋季雪雨比在不同海拔和部分气候分区都呈不显著下降趋势;冬季平均气温在海拔2000 m以上呈现显著升温,且随着海拔的升高升温速率加快,空间上在青藏高原地区、东南部半干旱区、半湿润区呈现显著升温,降雪量在1000~2000 m呈现显著增加趋势,空间上在北疆地区呈现显著增加趋势。②降雪开始日期随着温度的升高在所有区域都没有显著的推迟,每一年的降雪开始日期在不同高程带和不同气候区之间的差别没有变化,仍为30~40d。③融雪开始日期在所有海拔区间和气候分区都呈现出显著的提前趋势,每一年的融雪开始的日期在不同高程带和不同气候区的差别仍为25~30d。降雪和融雪特征的变化说明气候变化可能已经对融雪洪水的特征产生了明显的影响。 相似文献
13.
利用1961-2008年青海南部牧区地面气象观测资料、74个环流特征量和北半球500 hPa高度场网格点资料,整理了地表积雪序列和雪灾年表,并对积雪的变化趋势和雪灾发生的机理进行了研究。结果表明,1961-2008年青南牧区共有16 a发生积雪灾害,占总年数的33.33%。在4 450 m以下,累计积雪量随海拔高度的升高而增加,在4 451 m以上,累计积雪量随海拔高度的升高而减小。典型多积雪年新地岛地区的冷空气偏强、高原低值系统活动偏多,新地岛的冷空气容易沿偏西北路径侵入青南高原与高空槽前的暖湿空气汇合,形成云雨的物理条件充分,降雪多、积雪厚。典型少积雪年环流形势与上述基本相反。10-12月北美区极涡面积偏大和欧亚经向环流偏强、10月欧亚经向环流偏强、11月大西洋欧洲环流型E型日数偏多、12月大西洋副高北界位置偏北均有利于前冬青藏高原高度场的偏低和青南牧区累计积雪量的偏多。这些环流因子在相反的配置下,容易导致青南牧区累计积雪量的偏少。前冬模拟预报方程对典型多积雪年和1993年以来的积雪变化趋势全部预测成功。 相似文献
14.
1970—2018年秦岭南北冷季降雪量时空变化及其影响因素 总被引：1，自引：0，他引：1
基于72个气象站点逐日观测数据,对1970/1971—2018/2019年秦岭南北冷季（11月~次年5月）降水类型（降雪、降雨和雨夹雪）进行识别;重点关注降雪时空变化特征,探讨降雪与气温、湿球温度的响应关系;依据“夏季-秋季-冬季”Niño 3.4区海温异常状态,细化4种不同发展过程的厄尔尼诺-南方涛动（ENSO）事件,分析降雪异常与不同ENSO事件的对应关系。结果表明：① 相比气候平均态（1970—2000年）,1990—2018年,秦岭南坡（山地暖温带）降雪量下降了3.1 mm,基本与关中平原降雪量（17.1 mm）持平;② 空间趋势上,低海拔河谷地带降雪量以年代波动为主,山地高海拔地区为降雪下降区;③ 秦岭高山地区气温或湿球温度每升高1.0℃,降雪量分别下降23.1 mm和24.3 mm;从地带性角度分析,由北向南气温或湿球温度每升高1.0℃,秦岭南北降雪量分别下降3.0 mm和2.8 mm;④ 当厄尔尼诺/拉尼娜持续型发生时,关中平原降雪异常偏多;当拉尼娜发展型发生时,秦岭山地和大巴山区降雪异常偏少。当厄尔尼诺发展型发生时,秦岭南北降雪异常呈现“东西分异”,秦岭山地东部和关中平原为降雪异常偏少区。 相似文献
15.
The purpose of this research is to develop a better understanding of the spatial and temporal aspects of central Great Plains snowstorms by: (1) identifying trends in the frequency of snow events, (2) determining the relative importance of significant snowfalls (those producing snowfall amounts of 10 cm or more), and (3) identifying temporal and/or latitudinal variations in the frequency of significant snowstorms. Using NCDC data from cooperative program weather stations along a north-south transect, summary statistics, correlation coefficients, and frequency histograms were generated. The results provided evidence of a highly variable spatial and temporal record. Significant snowstorms are more critical to total snowfall amounts in Nebraska, Kansas, and Texas. Although strong, regionally coherent temporal trends were not detected, a predominance of January through March snow events was observed. The greater frequency of January snowstorms coincides with the mean position of the polar front, while February and March snowfall frequency reflects the increased incidence of Colorado cyclones. Decadally, snowfall variability corresponds with a change in mean temperatures and predominant upper atmospheric flow that occurred around 1950. This change brought less snow to the Southern and Central Plains states, but more snow to the north. [Key words: snowfall, Great Plains, temporal/spatial variability.] 相似文献
16.
Diatom-based models for reconstructing past water quality and productivity in New Zealand lakes 总被引：17，自引：12，他引：5
The trophic status of lakes in New Zealand is, on average, low compared to more densely populated areas of the globe. Despite this, trends of eutrophication are currently widespread due to recent intensification in agriculture. In order to better identify baseline productivity and establish long-term trends in lake trophic status, diatom-based transfer functions for productivity-related parameters were developed. Water quality data and surface sediment diatom assemblages from 53 lakes across the North and South Islands of New Zealand were analysed to determine species responses to the principal environmental gradients in the data set. Repeat sampling of water chemistry over a 12-month period enabled examination of species responses to annual means as well as means calculated for stratified and mixed periods. Variables found to be most strongly correlated with diatom species distributions were chlorophyll a (Chl a), total phosphorus (TP), dissolved reactive phosphorus (DRP), ionic concentration (measured as electrical conductivity (EC)) and pH. These variables were used to develop diatom-based transfer functions using weighted averaging regression and calibration (simple, tolerance down-weighted and with partial least squares algorithm applied). Overall, models derived for stratified means were weaker than those using annual or isothermal means. For specific variables, the models derived for the isothermal mean of EC (WA-tol r2jack = 0.79; RMSEP = 0.15 log10 S cm–1),the annual mean of pH (WA r2jack = 0.72; RMSEP = 0.25 pH units) and the isothermal mean of Chl a (WA r2jack = 0.71; RMSEP = 0.18 log10 mg m–3 Chl a) performed best. The models derived for TP were weak in comparison (for the annual mean of TP: WA r2jack = 0.50; RMSEP = 0.24 log10 mg m–3 TP) and residuals on estimates for this model were correlated with several other water quality variables, suggesting confounding of species responses to TP concentrations. The model derived for the isothermal mean of DRP was relatively strong (WA-tol r2jack = 0.78; RMSEP = 0.17 log10 mg m–3 DRP); however, residual values for this model were also found to be strongly correlated with several other water quality variables. It is concluded that the poor performance of the TP and DRP transfer functions relative to that of the Chl a model reflects the coexistence of nitrogen and phosphorus limitation within the lakes in the data set. In spite of this, the suite of transfer functions developed from the training set is regarded as a valuable addition to palaeolimnological studies in NewZealand. 相似文献
17.
基于1961—2020年9个国家气象观测站逐日资料,采用气候统计学方法分析了塔城地区不同相态降水的时空分布及变化规律,探讨了降水相态的变化成因及其可能影响。结果表明：（1） 近60 a塔城地区年平均降水日数88.1 d,其中降雨日数最多,降雪日数次之,雨夹雪日数最少;3种相态降水在空间上呈现地区西北部多、中东部少的分布格局。（2） 从不同相态降水日数的月际分布来看,降雨主要出现在4—9月,降雪在11月—翌年3月较多,3—4月和10—11月期间3种相态降水共存。（3） 近60 a塔城地区各站不同相态降水的变化趋势存在一定的差异,总体呈现降雨日数增加而降雪日数减少的变化趋势,且降雨量的增速高于降雪量增速,其结果导致雪雨比率以-0.33%·(10a)-1的速率减小。（4） 气温增暖是塔城地区降水相态向多雨化转变的主要原因,同时北极涛动指数（Arctic oscillation index,AO）、北大西洋涛动指数（North Atlantic oscillation index,NAO）以及北半球极涡指数对降水相态的变化也有一定的影响。 相似文献
18.
Diatom-based conductivity and water-level inference models from eastern Tibetan (Qinghai-Xizang) Plateau lakes 总被引：7，自引：0，他引：7
Xiangdong Yang Christian Kamenik Roland Schmidt Sumin Wang 《Journal of Paleolimnology》2003,30(1):1-19
Climate in central Asia is dominated by the Asian monsoon. The varying impact of the summer monsoon across the Tibetan (Qinghai-Xizang) Plateau provides a strong gradient in precipitation, resulting in lakes of different salinity. Diatoms have been shown to indicate changes in salinity. Thus, transfer functions for diatoms and salinity or related environmental variables represent an excellent tool for paleoclimatic reconstructions in the Tibetan Plateau. Forty freshwater to hypersaline lakes (salinity: 0.1 to 91.7 g l–1) were investigated in the eastern Tibetan Plateau. The relationship between 120 diatom taxa and conductivity, maximum water depth and major ions were analyzed using an indicator value approach, ordination and taxon response models. Canonical correspondence analysis indicated that conductivity was the most important variable, accounting for 10.8% of the variance in the diatom assemblages. In addition water depth and weathering were influential. Weighted Averaging (WA) and Weighted Averaging Partial Least Square (WA-PLS) regression and calibration models were used to establish diatom-conductivity and water depth transfer functions. An optimal two-component WA-PLS model provided a high jack-knifed coefficient of prediction for conductivity (r2
jack = 0.92), with a moderate root mean squared error of prediction (RMSEPjack = 0.22), a very low mean bias (0.0003), and a moderate maximum bias (0.26). A WA model with tolerance downweighting resulted in a slightly lower r2
jack (0.89) for water depth, with RMSEPjack= 0.26, mean bias = –0.0103 and maximum bias = 0.26. 相似文献
19.
The chemistry of precipitation, snow pack and surface water has been analysed on 205 samples collected during the 2001 field season at 25 selected sites within the Latnjavagge drainage basin in arctic–oceanic northern Swedish Lapland. Additionally, daily discharge and yield of dissolved solids have been calculated for several subcatchments and the entire Latnjavagge catchment during the years 2000, 2001 and 2002. Chemical water analysis included the components Ca2+, Mg2+, Na+, K+, Fe2+, Mn2+, Cl−, NO3−, SO42− and PO43−, with SO42− and Ca2+ being the dominant ones in the surface water. Solute concentrations and chemical denudation were low, but showed significant differences within the basin. In areas of shade, longer snow cover, frozen ground and thin regolith, concentrations over the summer were perceptible but so low that solutes brought into the basin from precipitation could be detected in the surface water. In one locality, it was even found that lake water could reflect snowmelt to such an extent that the solute concentration was less than that of summer precipitation. The highest concentrations were found at a radiation-exposed, W-facing, vegetated, moderately steep slope with relatively thick regolith that was thawed at the time of snowmelt in early June. In such well-drained sites with continuous subsurface water flow, a maximum of contact between water and mineral particles could take place. The concentration values revealed differences in the rate of thawing of frozen ground between shaded areas and/or areas at higher altitude on the one hand and radiation-exposed areas on the other. A comparison with published results from Kärkevagge a few kilometres to the northwest as well as from other periglacial locations indicates that the chemical denudation values from Latnjavagge are more representative of periglacial oceanic environments than the values from the Kärkevagge catchment, which shows especially high chemical denudation rates. The investigation in Latnjavagge stresses the importance of spatial variability within even small catchments of homogeneous lithology as it demonstrates that solute concentrations from different subbasins can differ substantially dependent on exposure to radiation, duration of snow cover and frozen ground conditions, regolith thickness and possibly also to vegetation cover and slope angle as factors steering water turbulence and retention of drainage. 相似文献
20.
RS与GIS支持下的草地雪灾监测试验研究 总被引：32，自引：0，他引：32
冬季降雪是影响我国北方草原牧区畜牧业发展的重要因子。在草地雪灾监测和危险性评价过程中，确定积雪区域和积雪深度与牧草高度之间的关系是关键步骤。通过在内蒙古锡林郭勒草原的试验研究，可以认为：应用ＮＯＡＡ／ＡＶＨＲＲ气象卫星资料确定积雪分布范围、应用地面气象站观测的降雪量资料及由ＤＥＭ生成的地形参数确定积雪深 是在较大范围内进行雪灾监测的有效方法。 相似文献