共查询到20条相似文献，搜索用时 15 毫秒
1.
采有英国Hadley中心的GISST海冰面积资料，NCFP／NCAR再分析资料以及中国160站气温和降水资料，分析了春季格陵兰海冰面积与夏季中国区域气温和降水的关系。初步研究表明，春季格陵兰海冰面积变化和随后夏季我国黄河长江中下游之间地区气温以及8月份华北和西南地区降水呈明显正相关，而和6月黄河中上游地区降水则具有明显的负相关。同时，春季格陵兰海冰异常时期对应着北半球大气环流的明显主为化，表明海冰与我国气温及降水之间的联系具有一定的环流背景。 相似文献
2.
西藏色齐拉山地区立体气候特征初步分析 总被引：1，自引：0，他引：1
利用西藏色齐拉山地区不同海拔高度的8个自动站和3个实测气象站1年的近地面观测资料,分析了该地区气温、地温、降水量、湿度和风速等气象要素的季节变化特征,探讨了东、西坡局地气候特征差异形成的原因。结果表明:色齐拉山地区1月为最冷月、7月为最暖月;月平均最高气温、最低气温与平均气温的季节变化一致。气温日较差大年较差小。年平均气温直减率东、西坡分别为0.54℃/100m和0.73℃/100m,西坡大于东坡。地气温差冬季西坡大于东坡,夏季东坡大于西坡。年、月平均地温直减率西坡仍大于东坡;东坡除夏季7、8月份外,地温直减率小于气温直减率;西坡除冬季(12月和1月),地温直减率大于气温直减率。降水量东坡比西坡多,海拔2500m以上地区4~10月降水总量随着海拔高度的升高呈增加趋势,增加率为20.9mm/100m。空气相对湿度冬季低夏季高,年变化呈单峰型。东、西坡冬季风速较强夏季相对较弱,初春风速最大。东、西坡气候差异与海拔高度、坡向、下垫面性质有关。 相似文献
3.
Based on the data of monthly mean air temperature and precipitation from about 400 stationsin 1951—1995.and the data of maximum and minimum air temperatures,relative humidity,totalcloud cover and low-cloud cover,sunshine duration,evaporation,wind speed,snow-covered daysand depth,and soil temperatures in 8 layers from 0 m down to 3.2 m from 200 odd stations in 1961—1995.the climate change and its characteristics in China in recent 45 years have been analyzedand studied comprehensively.This paper,as the first part of the work.has analyzed the climatechange and regularities of such meteorological elements as mean air temperature,maximum andminimum air temperatures,precipitation,relative humidity and sunshine duration.The possiblemechanism on climate change in China and the climate change and regularities of othermeteorological elements will be discussed in another paper as the second part. 相似文献
4.
额济纳绿洲夏末典型晴天小气候特征分析 总被引：5，自引：3，他引：5
绿洲系统特有的地理地貌形成了绿洲特殊的小气候特征。利用额济纳绿洲2003年9月8～10日小气候观测资料，分析了绿洲柽柳林的小气候特征。在柽柳林内，地表和近地层大气温度有明显的日变化，日间地表给大气加热，大气温度呈超绝热递减率随高度递减；夜间大气给地表加热，大气为稳定层结。近地层空气湿度的日变化与温度相反。林内空气温度的垂直分布主要取决于冠层与地表吸收太阳辐射状况。在林冠顶层，白天以上升气流为主，夜间以下沉气流为主，绿洲荒漠环流效应已经不明显。绿洲上空大气浑浊度小，对太阳辐射的削减较少，绿洲具有很好的光资源背景。 相似文献
5.
The results of our 1993 and 1994 experiments at the Tsimlyansk experimental site are given. Spatial variations of small-scale (0.1 m < l < 100 m) temperature inhomogeneities of a steppe surface have been measured. Considerable variations in surface radiation temperature Tr, with variances up to 5 K2, have been found. The spectra of Tr variations are of a one-mode character. The position of the spectral maximum on the wavenumber scale depends on the surface characteristics and may change from year-to-year. Probability density distributions for steppe surface radiation temperature variations are close to a normal distribution. 相似文献
6.
Wim Klaassen 《Boundary-Layer Meteorology》1992,58(4):329-354
Using a surface-layer model, fluxes of heat and momentum have been calculated for flat regions with regularly spaced step changes in surface roughness and stomatal resistance. The distance between successive step changes is limited to 10 km in order to fill the gap between micro-meteorological measurements and meso-scale models. A single-layer big leaf model of the vegetation is compared with a multi-layer model to assess the performance of the former in the determination of surface fluxes in heterogeneous terrain.The sub-models of vegetation and atmosphere are mainly based on well-known theory. However, a modification of the mixing-length closure of atmospheric exchange is included to achieve a more realistic calculation of fluxes near step changes at the surface. Measurements, presented in the literature, are used to determine the mixing-length parameters and to validate the calculated fluxes downwind of a change in vegetation cover.The single-layer model, well validated for homogeneous surfaces, underestimates the effects of local advection upon the surface fluxes as this model neglects air flow across the edges of tall vegetation. Using the multi-layer model, local advection results in an increase of up to 50% in regional momentum flux and smaller changes in regional evaporation. Even widely spaced heterogeneities appear to influence regional fluxes. 相似文献
7.
Yaohui Li Cailing Zhao Tiejun Zhang Wei Wang Haixia Duan Yuanpu Liu Yulong Ren Zhaoxia Pu 《Acta Meteorologica Sinica》2018,32(6):896-908
This study examines the impacts of land-use data on the simulation of surface air temperature in Northwest China by the Weather Research and Forecasting (WRF) model. International Geosphere–Biosphere Program (IGBP) landuse data with 500-m spatial resolution are generated from Moderate Resolution Imaging Spectroradiometer (MODIS) satellite products. These data are used to replace the default U.S. Geological Survey (USGS) land-use data in the WRF model. Based on the data recorded by national basic meteorological observing stations in Northwest China, results are compared and evaluated. It is found that replacing the default USGS land-use data in the WRF model with the IGBP data improves the ability of the model to simulate surface air temperature in Northwest China in July and December 2015. Errors in the simulated daytime surface air temperature are reduced, while the results vary between seasons. There is some variation in the degree and range of impacts of land-use data on surface air temperature among seasons. Using the IGBP data, the simulated daytime surface air temperature in July 2015 improves at a relatively small number of stations, but to a relatively large degree; whereas the simulation of daytime surface air temperature in December 2015 improves at almost all stations, but only to a relatively small degree (within 1°C). Mitigation of daytime surface air temperature overestimation in July 2015 is influenced mainly by the change in ground heat flux. The modification of underestimated temperature comes mainly from the improvement of simulated net radiation in December 2015. 相似文献
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利用1961—2004年我国西南地区322个站的气温观测资料, 分析了乡村站、小城市站、大中城市站和国家基准/基本站气温变化趋势特点, 着重研究了城市化对城镇站和国家站地面气温记录的影响程度和相对贡献比例。结果显示:区域平均的各类台站年平均气温呈现不同程度的上升趋势, 城市站、国家站的增温速率均高于乡村站。大中城市站和国家站的年平均热岛增温率分别为0.086 ℃/ 10a和0.052 ℃/10a, 其增温贡献率分别达57.6%和45.3%。与大多数地区不同, 西南地区的增温速率明显偏小。因此, 尽管平均热岛强度变化比许多地区弱, 但其相对贡献明显, 表明城市化对该区域气温趋势的绝对影响较弱, 但相对影响较强。另外, 城市热岛增温有明显的季节变化, 表现为秋季最强, 春季或冬季次之, 夏季最弱。热岛增温贡献率则为春季最大 (100%), 夏季次之 (73%以上), 秋季和冬季相对较小。这主要是因为春、夏两季背景气候变凉或趋势微弱, 热岛增温在实际增温中占有更高的比例。 相似文献
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The Beijing meteorological tower is located in an area of Beijing, China, which has developed from a suburban to an inner city setting over the past 30 years. The impacts of this urbanization process on both the vertical profile and diurnal cycles of air temperature are investigated using hourly data collected from a series of monitoring levels (up to 325 m high) on the Beijing meteorological tower since 1984. We find that the inter-decadal temperature has increased gradually, and that a more significant increase occurred during the 1980s and 1990s due to the effects of urbanization. A well-defined change in temperature stratification was also observed over this period. The height of the temperature inversion layer decreased from the 1980s to the 2000s. A well-defined nighttime temperature inversion developed below 50 m during the summer in the 1980s, but this near-surface inversion is not seen in data from the 1990s and 2000s. This change can be related to an increase in turbulent mixing caused by urban roughness and surface heat storage that disturbs the near-surface temperature inversion layer. In addition, the diurnal change in temperature in the city in summer shows a maximum increase from sunrise to the early afternoon, which is mainly caused by the nature variability and global warming in both the summer and winter. The urbanization mainly contributes to the temperature increase in the afternoon and nighttime. Moreover the urbanization dominates the increase in daily mean near-surface temperature. 相似文献
12.
A warm on-ice air flow from the open water over the Arctic sea ice in the Fram Straitwas, for the first time, systematically measured on 12 March 1998 by aircraft in thelowest 3 km over a 300-km long distance. The air mass modification and the processesinvolved are discussed.Over the water, air temperature was lower than water temperature so that a convectiveboundary layer (CBL) was present as initial condition. As soon as the CBL passed theice edge, a shallow stable internal boundary layer (IBL) was formed. In the residual CBL, turbulence and pre-existing convective clouds dissolved within about 20 km. Within about the same distance, due to the transition from unstable to stable stratification, the influence of surface friction increased in the IBL and decreased above the IBL with consequent generation of a low-level jet at IBL top. The IBL was strongly stratified with respect to both temperature and wind. The wind shear was around 0.1 s-1 so that the Richardson number in the IBL was subcritical and turbulence was generated. The IBL top grew to about 145 m over 230 km distance. The growth of the IBL was not monotonic and was influenced by (a) inhomogeneous ice surface temperatures causedby both different ice thickness and changes in the cloud conditions, and (b) leads in theice deck. At the front side of the on-ice flow, the air mass boundary between the warmair and the cold Arctic air was sharp (12 K over 10 km) at low levels and tilted withheight. Observations suggest that the stratified IBL was lifted as a slab on top of thecold air. 相似文献
13.
Cited are the latest data on the contemporary climate changes in surface air temperature (to the year 2011 inclusive). Substantiated is the necessity of extending the concept on the normals and anomalies of surface air temperature under conditions of the changing climate. Formulated is a concept of “dynamic normals” and “dynamic anomalies” of surface air temperature taking account of current trends of climate change and interseasonal variations. It is proposed to adopt this concept both for the problems of forthcoming climate change assessments and for the long-range forecasting out of the “limit of predictability.” An adaptive regression method is proposed to compute such dynamic normals as a function of the indicator of global climate changes. Presented are the skill scores of dynamic normals as of “intermediate” forecasts (an analogue of the climate forecast under a changing climate). 相似文献
14.
中国东部冬季气温异常的主模态与大气环流的关系 总被引：4，自引：3，他引：1
利用中国东部季风区375个测站,1961-2006年历年平均地面气温资料,采用EOF、SVD、相关分析等方法,分析了中国东部季风区冬季气温与500hPa高度场异常变化的关系。结果表明:影响冬季气温的关键区有两个,皆为显著正相关;SVD分析表明:乌山脊弱,东亚槽浅,纬向环流偏强,经向环流偏弱,极涡面积偏小,使南下冷空气偏少,冬季气温易偏高。上年7月北大西洋高压异常偏强(偏弱),次年冬季气温将会异常偏暖(偏冷),北大西洋前期高度场与气温普遍有密切的关系,主要影响长江流域及其以北的季风中北部区;建立了气温距平与北大西洋关键区上年7月高度距平的关系,并建立了均生函数模型,预测了未来20 a的气温变化趋势。 相似文献
15.
Detecting and adjusting temporal inhomogeneity in Chinese mean surface air temperature data 总被引：18，自引：0，他引：18
LI Qingxiang LIU Xiaoning ZHANG Hongzheng Thomas C. PETERSON David R. EASTERLING 《大气科学进展》2004,21(2):260-268
Adopting the Easterling-Peterson (EP) techniques and considering the reality of Chinese meteorolog-ical observations, this paper designed several tests and tested for inhomogeneities in all Chinese historicalsurface air temperature series from 1951 to 2001. The result shows that the time series have been widelyimpacted by inhomogeneities resulting from the relocation of stations and changes in local environmentsuch as urbanization or some other factors. Among these factors, station relocations caused the largestmagnitude of abrupt changes in the time series, and other factors also resulted in inhomogeneities to someextent. According to the amplitude of change of the difference series and the monthly distribution featuresof surface air temperatures, discontinuities identified by applying both the E-P technique and supportedby China‘s station history records, or by comparison with other approaches, have been adjusted. Basedon the above processing, the most significant temporal inhomogeneities were eliminated, and China‘s mosthomogeneous surface air temperature series has thus been created. Results show that the inhomogeneitytesting captured well the most important change of the stations, and the adjusted dataset is more reli-able than ever. This suggests that the adjusted temperature dataset has great value of decreasing theuncertaities in the study of‘ observed climate change in China. 相似文献
16.
我国地面气温参考站点遴选的依据、原则和方法 总被引：17，自引：0，他引：17
由于城市化和观测环境变化的影响,我国现有国家级气象台站网观测的地面气温资料许多已不能满足气候变化检测研究的要求。利用我国全部气象观测站网的台站信息,对地面气温资料序列质量进行了系统评价,遴选出可用于气温变化研究的参考站点。这项工作建立了地面气温参考站点遴选的原则、方法和步骤,并据此确定了138个地面气温参考站。这些台站可代表背景地面气温场,其长期气温观测资料可用作城市台站或国家级台站城市化增温评价的参考,也可直接用于我国地面气温变化的检测分析。 相似文献
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Summary Near surface climate was observed through temperature profiling from the surface to 2.47 m height in an urban vegetated park
and its surroundings in central Stockholm, Sweden. Measurements were conducted during three summer days by mobile traverses.
Air temperature differences between the built-up area and the park were in the range of 0.5–0.8 °C during the day and reached
a maximum of 2 °C at sunset. The thermal stratification of the air was mainly stable in the park and unstable in the built-up
area. Inverse air temperature profiles in the park were less stable in open than in shady areas, and close to neutral at midday.
The most unstable air was found in the north–south orientated canyons in the early afternoon. Possible heat advection from
the surroundings, and thus uncoupling between the surface and the air, was identified through temperature gradients pointing
at different directions within the 2.47 m profile. Examples at midday indicated that warm air advected as far as 150 m into
the park. 相似文献
19.
The paper reports on detection and quantification of the impact of local anthropogenic structures and regional climatic changes on subsurface temperature field. The analyzed temperature records were obtained by temperature monitoring in a borehole in Prague-Spo?ilov (Czechia) and by repeated logging of a borehole in ?empeter (Slovenia). The observed data were compared with temperatures yielded by mathematical 3D time-variable geothermal models of the boreholes’ sites with the aim to decompose the observed transient component of the subsurface temperature into the part affected by construction of new buildings and other anthropogenic structures in surroundings of the boreholes and into the part affected by the ground surface temperature warming due to the surface air temperature rise. A direct human impact on the subsurface temperature warming was proved and contributions of individual anthropogenic structures to this change were evaluated. In the case of Spo?ilov, where the mean annual warming rate reached 0.034°C per year at the depth of 38.3?m during the period 1993–2008, it turned out that about half of the observed warming can be attributed to the air (ground) surface temperature change and half to the human activity on the surface in the immediate vicinity of the borehole. The situation is similar in ?empeter, where the effect of the recently built surface anthropogenic structures is detectable down to the depth of 80?m and the share of the anthropogenic signal on the non-stationary component of the observed subsurface temperature amounts to 30% at the depth of 50?m. 相似文献
20.
本文根据北半球500百帕图上552位势什米等高线所包围面积的大小，计算了1951—1980年历年逐月环极气流指数。通过对近30年来环极气流指数的分析，发现环极气流不但有明显的季节变化，而且还有2—4个月、5年、19—20年的周期性振动。在1951—1980年的30年中，五十年代环极气流收缩，六十年代环极气流扩张，七十年代以来则一直在平均值附近振动。环极气流指数与我国的气温和降水均有密切关系。当环极气流扩张（收缩）时，我国气温偏低（偏高）；降水在冬春和初夏季节偏少（偏多），在盛夏和秋季偏多（偏少）。这些结果可以用来很好地解释过去30年气候形成的原因。 相似文献