Estimation of the energy used to melt snow in the Tien Shan mountains and Japanese Islands     

Vladimir Aizen  Elena Aizen  John Melack  Tsutomu Nakamura  Shunichi Kobayashi 《Global and Planetary Change》2002,32(4)

The heat needed to melt snow over the Tien Shan mountains and Japanese Islands for 10-day period (TDP) was estimated. Melting curves and a map of snowmelt duration were obtained through the long-term data from 79 stations in the Tien Shan mountains and 20 stations in the Japanese Islands. At high elevations in the mountains, about 40% of the snow melts during penultimate 10 days of snow cover. In the Japanese Islands, about 80% of the snow melts during the last 20 days of snow cover. Over the mountains, 0.13×10⁴ MJ m² year⁻¹ is needed to melt snow in the northern and western Tien Shan where maximum snow accumulation occurred. The volume of air cooled 10 °C by snowmelt amounted to 4.4×10⁶ km³ year⁻¹ over the Tien Shan mountains and 3×10⁶ km³ year⁻¹ over the Japanese Islands. The most significant impact of snowmelt on air temperature was observed at an elevation of 2500 m in the western and northern Tien Shan. Air that was cooled 10 °C could reach an elevation of 2.1 km day⁻¹. Over the Japanese Islands, energy losses from snowmelt amounted to 0.26×10¹⁴ MJ year⁻¹ and the maximum occurred over Honshu Island. The heat loss from snowmelt in the Tien Shan mountains and Japanese Islands amounted to about 2/3 of heat loss in the Eurasian continental plains.  相似文献   

Statistical probability distribution of snow depth at the model sub‐grid cell spatial scale     

Wolf‐Dietrich Marchand  nund Killingtveit 《水文研究》2005,19(2):355-369

Comprehensive snow depth data, collected using georadar and hand probing, were used for statistical analyses of snow depths inside 1 km grid cells. The sub‐grid cell spatial scale was 100 m. Statistical distribution functions were found to have varying parameters, and an attempt was made to connect these statistical parameters to different terrain variables. The results showed that the two parameters mean and standard deviation of snow depth were significantly related to the sub‐grid terrain characteristics. Linear regression models could explain up to 50% of the variation for both of the snowcover parameters mentioned. Copyright © 2004 John Wiley & Sons, Ltd.  相似文献   

Design and realization of the drawing software for snow/ice stratigraphic profile     

温家洪  杨文璐 《极地研究(英文版)》2003,14(1)

1　IntroductionSnow/icestratigraphicprofileisoneofthetraditionalandimportantresearchfieldsinglaciology (Qin 1 995 ;Xie 1 988) .Thesnow pitprofilesareobserveddirectlyinthefield ,andthestratigraphicprofilesoficecoresaredelineatedandcompiledindetailat1∶1scalethroughnakedeyesinlow temperaturelaboratory .Themajorstratigraphicchar acteristicsobservedincludingcrystalgrainsize,structureofdepthhoar,lighttransmis sion,meltphenomena,windcrustetc.(ShojiandLangway 1 989) ,arenecessarytobedelineatedindia…  相似文献   

2013年冬季广东罕见持续暴雨过程特点及成因   总被引：1，自引：0，他引：1  

邓文剑  吴乃庚  林良勋  张华龙 《气象科技》2015,43(2):276-282

利用常规气象观测站、区域自动站资料和NCEP/NCAR客观分析资料等,对2013年12月13—17日广东出现的持续时间长、影响范围广和累计雨量大的罕见暴雨过程特征及成因进行了分析;对比分析了此过程与2008年年初持续低温雨雪冰冻过程形成的异同条件。结果表明:500hPa上在青藏高原附近建立"北脊南槽"的环流形势,促使北方冷空气沿脊前东移南下和来自南海、孟加拉湾沿南支槽前向东向北推进的暖湿气流在广东持续交绥,并在局地形成异常经向垂直环流,为持续性暴雨提供有利的环流背景条件;广东位于200hPa高空槽前部,处于高空急流入口区南侧的辐散、中低层辐合的区域中,也十分利于中低层水汽辐合抬升、凝结而产生暴雨。同2008年初持续低温雨雪冰冻过程相比较,这两次过程均发生在相似的"北脊南槽"形势下,但本次过程槽脊经向度大、南支槽位置偏南、降雨强度大;而2008年初过程则雨雪冰冻影响范围广和持续时间长;两过程虽同是在冬季低温背景下发生,而本次过程没有像2008年初过程那样在中层建立一强逆温层和低层形成一过冷却层,因而降水相态以雨为主,2008年初过程则以降雪冰冻(冻雨)天气为主。  相似文献   

Role of Ozone Deposition in the Occurrence of the Spring Maximum     

Alexander Liudchik  Viktar Pakatashkin  Siarhei Umreika  Rasele Girgzdiene 《大气与海洋》2015,53(1):42-49

Abstract

A hypothesis has been formulated on the basis of experimental data presented in this article. According to the hypothesis, occurrence of the spring surface ozone maximum at mid-latitudes results from a delay in snow-cover melt. The data were collected at ozone stations in Minsk (Belarus) and Preila (Lithuania). Because the measurements of surface ozone concentration are quite different, despite the close proximity of the stations, a conclusion can be drawn about the significant influence of meteorological parameters on measurements. In addition to a rather subjective and poorly defined parameter—time of snow melt—the difference between the average March temperature and a climatological mean may be treated as a criterion for the presence or absence of the spring ozone maximum.  相似文献   

2015年1月大气环流和天气分析   总被引：1，自引：0，他引：1  

尹姗  何立富 《气象》2015,41(4):514-520

2015年1月大气环流主要特征为：北半球极涡呈偶极型分布,中心气压均较常年偏低。欧亚中高纬环流呈三波型,以纬向环流为主;西太平洋副热带高压和南支槽的强度接近常年平均水平。1月全国平均气温为-3.1℃,较常年同期（-5.0℃）偏高1.9℃,为1961年以来同期最高。全国平均降水量14.4 mm,较常年同期(13.2 mm)偏多气候中心原数据为9.0,但计算为9.1,但分布极不均匀,西南地区、西北地区和华南南部降水偏多,而华北至江南一带则明显偏少,北京等地几乎无降水。月内仅在上旬出现了1次全国范围中等强度冷空气过程,而降水过程有5次。上旬后期,云南等地出现了创历史极值的强雨雪天气,气象干旱得到有效缓解。月末中东部地区出现入冬以来最大范围雨雪过程,贵州等地出现冻雨。中东部月内共出现3次大范围雾 霾天气。  相似文献   

2013年湖北省两次降雪过程对比分析   总被引：1，自引：1，他引：0  

张萍萍  吴翠红  祁海霞  王晓玲  张宁 《气象》2015,41(4):418-426

利用常规观测资料、NCEP再分析资料、微波辐射计及多普勒雷达等资料对2013年2月7—8日干雪过程、2月18—19日湿雪过程,从水汽、不稳定、动力及温湿层结方面进行对比分析,得出如下结论：（1）2月7—8日的干雪过程水汽层次浅薄,水汽输送支仅为700 hPa弱西南气流;2月18—19日的湿雪过程水汽充沛,水汽输送支为700 hPa强西南急流和850 hPa 东南气流。（2）干雪过程低层冷平流强,层结稳定。湿雪过程低层暖平流强,冷暖交汇使大气不稳定度增加。（3）干雪过程中弱暖湿气流沿深厚冷空气垫爬升,动力辐合位于中高层,次级环流的形成减弱上升运动。湿雪过程中弱冷空气楔入到强暖湿气流底部,迫使其抬升,形成深厚上升运动区,次级环流的形成增强上升运动。（4）干雪过程整层温度<0℃,700 hPa出现冷性逆温层,-10℃层位于925 hPa附近,水汽密度、液态水含量、整层水汽含量较小;湿雪过程700 hPa出现暖性逆温层,-10℃层位于500 hPa附近,水汽密度、液态水含量、整层水汽含量较大。在上述研究的基础上给出了干、湿雪形成的三维物理模型,该模型从温湿（风）垂直层结上面体现出了干、湿雪形成的主要环境背景差异,对于干、湿雪预报具有一定的参考价值。  相似文献   

Influence of canopy density on snow distribution in a temperate mountain range     

J. I. López‐Moreno  J. Latron 《水文研究》2008,22(1):117-126

We analyse spatial variability and different evolution patterns of snowpack in a mixed beech–fir stand in the central Pyrenees. Snow depth and density were surveyed weekly along six transects of contrasting forest cover during a complete accumulation and melting season; we also surveyed a sector unaffected by canopy cover. Forest density was measured using the sky view factor (SVF) obtained from digital hemispherical photographs. During periods of snow accumulation and melting, noticeable differences in snow depth and density were found between the open site and those areas covered by forest canopy. Principal component analysis provided valuable information in explaining these observations. The results indicate a high variability in snow accumulation within forest areas related to differences in canopy density. Maximum snow water equivalent (SWE) was reduced by more than 50% beneath dense canopies compared with clearings, and this difference increased during the melting period. We also found significant temporal variations: when melting began in sectors with low SVF, most of the snow had already thawed in areas with high SVF. However, specific conditions occasionally produced a different response of SWE to forest cover, with lower melting rates observed beneath dense canopies. The high values of correlation coefficients for SWE and SVF (r > 0·9) indicate the reliability of predicting the spatial distribution of SWE in forests when only a moderate number of observations are available. Digital hemispherical photographs provide an appropriate tool for this type of analysis, especially for zenith angles in the range 35–55 . Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

Long‐term change of seasonal snow cover and its effects on river runoff in the Tarim River basin,northwestern China     

Changchun Xu  Yaning Chen  Yimit Hamid  Tiyip Tashpolat  Yapeng Chen  Hongtao Ge  Weihong Li 《水文研究》2009,23(14):2045-2055

Spatio‐temporal variation of snow depth in the Tarim River basin has been studied by the empirical orthogonal function (EOF) based on the data collected by special sensor microwave/imager (SSM/I) and scanning multichannel microwave radiometer (SMMR) during the period from 1979 to 2005. The long‐term trend of snow depth and runoff was presented using the Mann‐Kendall non‐parametric test, and the effects of the variations of snow depth and climatic factors on runoff were analysed and discussed by means of the regression analysis. The results suggested that the snow depth variation on the entire basin was characterised by four patterns: all consistency, north–south contrast, north‐middle‐south contrast and complex. The first pattern accounting 39·13% of the total variance was dominant. The entire basin was mainly affected by one large‐scale weather system. However, the spatial and temporal differences also existed among the different regions in the basin. The significant snow depth changes occurred mainly in the Aksu River basin with the below‐normal snow depth anomalies in the 1980s and the above‐normal snow depth anomalies in the 1990s. The long‐term trend of snow depth was significant in the northwestern, western and southern parts of the basin, whereas the long‐term trend of runoff was significant in the northwestern and northeastern parts. The regression analysis revealed that the runoff of the rivers replenished by snow melt water and rainfall was related primarily to the summer precipitation, followed by the summer temperature or the maximum snow depth in the cold season. Our results suggest that snow is not the principal factor that contributes to the runoff increase in headstreams, although there was a slow increase in snow depth. It is the climatic factors that are responsible for the steady and continuous water increase in the headstreams. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   

Estimating the spatial distribution of snow water equivalent in an alpine basin using binary regression tree models: the impact of digital elevation data and independent variable selection     

N. P. Molotch  M. T. Colee  R. C. Bales  J. Dozier 《水文研究》2005,19(7):1459-1479

  相似文献