共查询到20条相似文献，搜索用时 765 毫秒
1.
A. E. Barkaoui A. Correia Y. Zarhloule A. Rimi J. Carneiro M. Boughriba M. Verdoya 《Climatic change》2013,118(2):431-441
Data from temperature measurements in boreholes are indicators of the temperature variations associated with past climate change. This paper is a contribution to reconstruct the ground surface temperature history (GSTH) from geothermal data in the eastern part of Morocco. From a set of several temperature logs, measured in the study area, only two were found suitable for estimating the ground surface temperature history (GSTH). In order to reconstruct the surface temperature past changes the functional space inversion method (FSI) was used. The inversion reveals a recent warming in the last century with respective amplitude of 0.1 °C and 1 °C for the boreholes 2952 in Oujda and 1624 in Berkane. These results can be confirmed by the air temperature record of the meteorical station in Oujda despite the scarceness of data beyond 1959. 相似文献
2.
为提高地基反演大气可降水量中加权平均温度的计算精度和效率,以香港市域为例,根据2017年香港无线电探空资料,设计了一种以地面气压为基础的大气加权平均温度模型,并通过2014—2016年探空数据对该模型进行验证,分析表明该模型与探空数据得到的加权平均温度有良好的一致性,具有较高的精度。基于气压回归模型和气温回归模型对2017年7月香港地区进行地基反演大气可降水量,验证新建模型的水汽反演精度。结果表明,该模型能很好的满足地基反演大气可降水量的精度要求,相比于气温回归模型反演精度有了较好的提升。 相似文献
3.
Xuechun LUO Xiao TANG Haoyue WANG Lei KONG Huangjian WU Weiguo WANG Yating SONG Hongyan LUO Yao WANG Jiang ZHU Zifa WANG 《大气科学进展》2023,40(4):601-618
In recent years, China has implemented several measures to improve air quality. The Beijing-Tianjin-Hebei(BTH)region is one area that has suffered from the most serious air pollution in China and has undergone huge changes in air quality in the past few years. How to scientifically assess these change processes remain the key issue in further improving the air quality over this region in the future. To evaluate the changes in major air pollutant emissions over this region, this paper employs ens... 相似文献
4.
Oleg A. Anisimov 《Climatic change》2001,50(3):297-315
The signal of recent global warming has been detected in meteorological records, borehole temperatures and by several indirect climate indicators. Anthropogenic warming continues to evolve, and various methods are used to study and predict the changes of the global and regional climate. Results derived from GCMs, palaeoclimate reconstructions, and regional climate models differ in detail. An empirical model could be used to predict the spatial pattern of the near-surface air temperature and to narrow the range of regional uncertainties. The idea behind this approach is to study the correlations between regional and global temperature using century-scale meteorological records, and to evaluate the regional pattern of the future climate using regression analysis and the global-mean air temperature as a predictor. This empirical model, however, is only applicable to those parts of the world where regional near-surface air temperature reacts linearly to changes of the global thermal regime. This method and data from a set of approximately 2000 weather stations with continuous century-scale records of the monthly air temperature was applied to develop the empirical map of the regional climate sensitivity. Data analysis indicated that an empirical model could be applied to several large regions of the World, where correlations between local and global air temperature are statistically significant. These regions are the western United States, southern Canada, Alaska, Siberia, south-eastern Asia, southern Africa and Australia, where the correlation coefficient is typically above 0.9. The map of regional climate sensitivity has been constructed using calculated coefficients of linear regression between the global-mean and regional annual air temperature. As long as the correlations between the local and global air temperature are close to those in the last several decades, this map provides an effective tool to scale down the projection of the global air temperature to regional level. According to the results of this study, maximum warming at the beginning of the 21st century will take place in the continental parts of North America and Eurasia. The empirical regional climate sensitivity defined here as the response of the mean-annual regional temperature to 1 °C global warming was found to be 5–6 °C in southern Alaska, central Canada, and over the continental Siberia, 3–4 °C on the North Slope of Alaska and western coast of the U.S.A., and 1–2 °C in most of the central and eastern U.S.A. and eastern Canada. Regions with negative sensitivity are located in the southeastern U.S.A., north-western Europe and Scandinavia. The local tendency towards cooling, although statistically confirmed by modern data, could, however, change in the near future. 相似文献
5.
Urban heat island diagnosis using ASTER satellite images and ‘in situ’ air temperature 总被引：1，自引：0，他引：1
This study demonstrates that thermal satellite images combined with ‘in situ’ ground data can be used to examine models of heat island genesis and thus identify the main causes of urban heat islands (UHIs). The models, although proposed over 30 years ago, have not been thoroughly evaluated due to a combination of inadequate ground data and the low resolution of thermal satellite data. Also there has been limited understanding of the relevance of satellite-derived surface temperatures to local and regional scale air temperatures. A cloud-free ASTER thermal image of urban and rural areas of Hong Kong was obtained on a winter night with a well-developed heat island, accompanied by a 148 km vehicle traverse of air temperatures. Over the whole traverse a high R2 of 0.80 was observed between surface and air temperatures, with the two datasets showing a similar amplitude and general trend, but with the surface exhibiting much higher local variability than air temperature. Gradients in both surface and air temperature could be related to differences in land cover, with little evidence of large scale advection, thus supporting the population/physical structure model of UHI causation, rather than the advection model. However, the much higher surface and air temperatures observed over the largest urban area, Kowloon, than over any smaller urban centre with similar physical structure in the New Territories, would seem more indicative of the advection model. The image and ground data suggest that Kowloon's urban canopy layer climate is mainly influenced by local city structure, but it is also modified by a strongly developed, regional scale urban boundary layer which has developed over the largest urban centre of Kowloon, and reinforces heating from both above and below. 相似文献
6.
Masahiro Kajikawa Katsuhiro Kikuchi Yoshio Asuma Yusuke Inoue Noboru Sato 《Atmospheric Research》2000,52(4):377
Supercooled drizzle (freezing drizzle) was observed at Inuvik, N.W.T., Canada (68°22′N, 133°42′W) on December 20, 21 and 27, 1995. Meteorological conditions in which the supercooled drizzle could form under low temperatures (colder than −20°C) in the mid-winter season of the Canadian Arctic were examined from the sounding data and data measured by a passive microwave radiometer at ground level. The following results were obtained. (1) Supercooled drizzle fell to the ground with ice pellets and frozen drops on snow crystals. (2) The maximum size of supercooled drizzle particles increased as the depth of cloud layer saturated with respect to water increased. (3) Because a layer of air temperature higher than 0°C was not detected from the sounding data at Inuvik, melting of snow particles was impossible. It was concluded, therefore, that supercooled drizzle was formed by the condensation–coalescence process below freezing temperature. 相似文献
7.
8.
Permafrost Thaw Accelerates in Boreal Peatlands During Late-20th Century Climate Warming 总被引：7，自引：0，他引：7
Philip Camill 《Climatic change》2005,68(1-2):135-152
Permafrost covers 25% of the land surface in the northern hemisphere, where mean annual ground temperature is less than 0°C. A 1.4–5.8 °C warming by 2100 will likely change the sign of mean annual air and ground temperatures over much of the zones of sporadic and discontinuous permafrost in the northern hemisphere, causing widespread permafrost thaw. In this study, I examined rates of discontinuous permafrost thaw in the boreal peatlands of northern Manitoba, Canada, using a combination of tree-ring analyses to document thaw rates from 1941–1991 and direct measurements of permanent benchmarks established in 1995 and resurveyed in 2002. I used instrumented records of mean annual and seasonal air temperatures, mean winter snow depth, and duration of continuous snow pack from climate stations across northern Manitoba to analyze temporal and spatial trends in these variables and their potential impacts on thaw. Permafrost thaw in central Canadian peatlands has accelerated significantly since 1950, concurrent with a significant, late-20th-century average climate warming of +1.32 °C in this region. There were strong seasonal differences in warming in northern Manitoba, with highest rates of warming during winter (+1.39 °C to +1.66 °C) and spring (+0.56 °C to +0.78 °C) at southern climate stations where permafrost thaw was most rapid. Projecting current warming trends to year 2100, I show that trends for north-central Canada are in good agreement with general circulation models, which suggest a 4–8 °C warming at high latitudes. This magnitude of warming will begin to eliminate most of the present range of sporadic and discontinuous permafrost in central Canada by 2100. 相似文献
9.
通过对陕西省7个国家气象站2014年新、旧双套自动站逐小时地面温度对比差值进行分析,发现利用现有观测方法和观测设备,地面温度观测值误差较大,数据一致率仅有93.67%,而超差率高达35.70%,且白天误差更为明显。通过对可能影响地面温度观测值的因素进行深入分析,并结合试验结果,得出太阳辐射强度对地面温度观测差值的影响不大,而观测场土质、观测方法、传感器维护以及设备型号与其有密切关系。建议采用采样面积更大的观测设备或观测方法替代现有单支铂电阻直埋观测法。 相似文献
10.
Modelling results of precision temperature logs made to depths of up to several hundred meters in numerous wells in the Canadian Prairie provinces (mostly Alberta) show evidence of average warming at the ground surface (GST) of 2.1 K (standard deviation = 0.9 K) mostly in the second half of this century. The GST warming signal for which higher frequency noise is cut off by the earth, which acts as a low-pass filter, correlates with the surface air warming (SAT) measured at screen level. A spatial comparison is made between the SAT warming and the GST warming for the last four decades in this region. A GIS (Geographic Information System) area cross tabulation was performed through the intersection of the classes of the ground and surface warming maps with a resulting contingency coefficient C= 0.805. Identical grid samples extracted from the ground warming and surface warming maps were related statistically with a resulting correlation coefficient of r= 0.75. Differences in the magnitudes of the warming exist due to the limited number of compatible data sets, errors in ground warming and air warming reconstructions, and land surface changes affecting the energy balance and subsurface heat fluxes. The influence of these effects requires further study. It is unlikely that all of the sites for which GST warming has been proven to correlate with air warming would have identical topography, vegetation, and hydrogeological disturbances for an area as large as the one under study (about 720,000 km2). The warming effect in the study area, as preserved by the ground, is mainly climate related. 相似文献
11.
This study deals with potential changes in the relative humidity associated with global warming and their implications on
heat stress along the coastal region of the Mediterranean in the summer season. It is based on the assumption that the regional
warming will enhance the lower-level stability due to the thermal inertia of the sea with respect to its overlying air. The
enhanced stability implies more effective trapping of the near surface moisture, and as a result—further increase of the relative
humidity. The marine boundary layer over the Mediterranean is modeled. The central feature of the model is the marine inversion
capping the marine moist air, which intensity is positively correlated with the stability. Simple calculations indicate that
if the temperature increases, while the stability remains unchanged, the near-surface relative humidity would not be affected.
But, an increase in the stability would result in an increase in the near-surface relative humidity. This prediction is validated
through observed trends of the respective fields, using the NCEP/NCAR reanalysis data and soundings from the eastern Mediterranean.
The results are consistent in indicating an increase in the near-surface temperature, the lower-level stability and the relative
humidity over the eastern part of the Mediterranean, but not in its western part. The results for the eastern Mediterranean
support the expectation for an aggravation of heat stress beyond that imparted by the temperature rise. 相似文献
12.
Based on two field surveys of permafrost distribution, conducted 26 years apart, along the Mackenzie Highway south of Great Slave Lake, Canada, the southern limit of the sporadic discontinuous permafrost zone in the region has migrated northward by about 120 km. To substantiate that the disappearance of perennial frozen ground is largely caused by climatic warming, a detailed trend analysis of monthly air temperature records from nine weather stations was performed using the non-parametric Kendall's test. The results show that the region experienced a general warming trend for the period 1949–1989 and warming is more prominent in the minimum than the maximum temperature series. From estimates of the magnitude of warming trends on a monthly basis, the resultant increase in mean annual air temperature could readily lead to the observed northward migration of permafrost. 相似文献
13.
A Model to Predict Surface Temperatures 总被引：3，自引：0，他引：3
M.J. Best 《Boundary-Layer Meteorology》1998,88(2):279-306
A model to predict the surface temperature of a variety of surfaces is described. The model solves the surface energy balance equation iteratively, using only standard meteorological data. Since surface and soil temperature information is not required for initialisation, the model is portable and, in theory, could be used for any surface and location. It is shown that, in order to obtain the correct cooling rates for vegetation during the night, the direct influence of the ground flux must be removed from the energy balance equation for the layer of vegetation. A scheme that couples a vegetation canopy to the ground solely by radiation is described, giving satisfactory cooling rates when compared with observations. Observations from a field site at Cardington, near Bedford, UK, are used to test the accuracy of the model for road and grass surfaces. When compared against these data, the model predicts surface temperatures with a root mean square error of about 1 °C for the road and 2 °C for the grass. Data from other sources not only give similar results to the Cardington data, but also demonstrate that the model can reproduce the characteristics of wet and partially dry soils and also dry desert sand. A study of the sensitivity of the model to errors in the forcing data indicates that inaccuracies in the air temperature data lead to similar sized errors in the predicted surface temperatures. Fluctuations in the forcing data that are not resolved by the model will affect a grass surface much more than a road surface, due to the relatively small thermal inertia of the grass. 相似文献
14.
应用1971—2016年河西走廊东部代表站的地面观测资料、NCEP 2.5°×2.5°月均地面至300 hPa高空资料,2006—2016年民勤逐日07和19时每隔10 m加密高空资料,分析了近45年河西走廊东部冬季沙尘暴天气的年际变化特征。同时选取2016年11月两次沙尘暴天气过程从天气学成因、物理量场及近地面边界层特征等方面进行了诊断分析。结果表明:近45年河西走廊东部冬季沙尘暴日数呈减少趋势,产生大风沙尘天气的主要原因不仅与大型冷暖空气强度及环流形势有关,还与冷锋过境时间、日变化、近地层风速和干湿程度关系密切。夜间至早晨近地面逆温厚且强,大气层结稳定,削弱沙暴强度,而午后到傍晚,逆温薄而弱,大气层结不稳定性强,加强了动量下传和风速,增强沙暴强度。近地层越干,风速越大,沙暴越强。 相似文献
15.
Inter-annual and -decadal scale variability in drought over the Abitibi Plains ecoregion (eastern Canada) was investigated using a 380-year dendroclimatic reconstruction of the Canadian Drought Code (CDC; July monthly average) i.e., a daily numerical rating of the average moisture content of deep organic layers. Spectral analyses conducted on the reconstructed CDC indicated a shift in spectral power after 1850 leading toward a reduction in interdecadal variability and an increase in interannual variability. Investigation on the causes for this shift suggested a decrease in North Pacific forcing after the mid-nineteenth century. Cross-continuous wavelet transformation analyses indicated coherency in the 8–16 and 17–32-year per cycle oscillation bands between the CDC reconstruction and the Pacific Decadal Oscillation (PDO) prior to 1850. Following 1850, the coherency shifted toward the North Atlantic Oscillation (NAO). Principal component analysis conducted over varying time windows reaffirmed that the Pacific forcing was restricted to the period about 1750–1850. Prior to and after this period, the CDC was correlated with the NAO. The shift around 1850 could reflect a northward displacement of the polar jet stream induced by a warming of the sea surface temperature along the North Pacific coast. A northward displacement of the jet stream, which inhibits the outflow of cold and dry Arctic air, could have allowed the incursion of air masses from the Atlantic subtropical regions. 相似文献
16.
Summary Recent secular variations in the January circumpolar vortex over the Northern Hemisphere are examined by digitizing the latitude at which the 546 dam isoheight at 50 kPa crosses every 10° meridian from 1947–90. A statistically significant expansion of the vortex is detected from 1966–90. Most of the expansion occurred over the North Pacific Ocean in the vicinity of the Aleutian Low and a less dramatic but significant expansion also occurred over eastern Canada and northern New England. The only region where the vortex contracted significantly is over the western United States. The trough in the western Pacific expanded eastward across the International Date Line in the past quarter century and, in conjunction with the observed contraction over the western United States, indicates amplification of 50 kPa standing waves in the Western Hemisphere. This change in circulation regimes could account for the increased frequency of warm air masses and the decreased occurrence of the coldest wintertime air masses in Alaska.With 6 Figures 相似文献
17.
利用1979—2016年1月逐日0.125°×0.125° ERA-Interim再分析资料及冻雨观测资料,通过个例合成等方法,探讨了中国南方准静止锋和冬季大范围冻雨的关系。结果表明:（1）中国南方大范围冻雨受昆明和华南准静止锋共同影响呈东西带状分布;（2）青藏高原东侧逆温之强,范围之广以及水汽之充沛的主要原因,一是冷空气常堆积在横断山脉以东和南岭山脉以北等中国广大的南方地区,其形成机制主要为冷平流和绝热冷却,地势较高地带非绝热冷却也较明显;二是700和850 hPa暖平流形成的暖层也十分宽广;三是850 hPa源自中国南海和西太平洋的湿平流输送;（3）500 hPa东亚大槽、700 hPa南支槽、850 hPa反气旋和地面蒙古冷高压为青藏高原东侧对流层低层极地大陆性气团与热带海洋性气团和热带大陆性气团交绥创造了必要的环流条件;（4）东亚冷空气爆发从青藏高原东侧南下,迫使近地面暖湿气团抬升形成华南准静止锋。同时,受青藏高原东部地形的阻挡产生冷空气堆积。当冷空气堆积到一定厚度向西爬上低纬高原时,又与南支西风相遇形成昆明准静止锋。由昆明和华南准静止锋形成的复杂锋面结构,伴随宽广而强烈的逆温有利于中国南方大范围冻雨的产生。 相似文献
18.
On the Formation of an Elevated Nocturnal Inversion Layer in the Presence of a Low-Level Jet: A Case Study 总被引：1，自引：1，他引：0
We report on observed nocturnal profiles, in which an inversion layer is located at the core of a low-level jet, bounded between two well-mixed layers. High-resolution vertical profiles were collected during a field campaign in a small plain in the Israeli desert (Negev), distant 100 km from the eastern shore of the Mediterranean Sea. During the evening hours, the synoptic flow, superposed on the late sea breeze, forms a low-level jet characterized by a maximum wind speed of 12 m s −1 at an altitude of 150 m above the ground. The strong wind shear at the jet maximum generates downward heat fluxes that act against the nocturnal ground cooling. As a result, the typical ground-based nocturnal inversion is “elevated” towards the jet centre, hence a typical early morning thermal profile is observed a few hours after sunset. Since the jet is advected into the region, its formation does not depend on the presence of a surface nocturnal inversion layer to decouple the jet from surface friction. On the contrary, here the advected low-level jet acts to hinder the formation of such an inversion. These unusual temperature and wind profiles are expected to affect near-ground dispersion processes. 相似文献
19.
利用空气质量监测资料、高空和地面气象观测资料、NCEP再分析资料,对达州市2016年元旦节期间重污染天气过程特征及气象条件进行分析。结果表明:达州市此次重污染天气过程为长时间无冷空气活动,无降雨,大气污染物不断积聚形成。AQI日变化受污染源排放情况影响更大,早上低,白天逐渐增加,天黑后达到峰值。大气污染物的积累一般发生大气稳定度为中性或以上。AQI与08时和17时混合层厚度负相关,但日平均混合层厚度与AQI没有通过相关性检验。重污染时近地面有逆温层且逆温层较厚。AQI与逐日最高气温、日平均风速和日最大风速正相关,降雨对大气污染物稀释作用明显,特别是降雨持续时间长,雨量大效果更为显著。AQI逐时变化与温度正相关,与风速负相关。 相似文献
20.
使用2006年7月-2007年6月沪宁高速公路沿线梅村和仙人山站附近的逐分钟路面温度、气温、湿度、风向、风速、降水气象资料, 分析了梅村和仙人山不同季节和不同天气状况下路面温度的日变化特征。结果表明:不同季节路面温度和气温具有明显的日变化;日出至日落时段,路面温度与气温有较大差异。在此基础上,应用逐步回归方法建立了梅村和仙人山最高和最低路面温度统计模型, 得出最低路面温度模型模拟结果与实况的变化趋势接近,误差绝对值不超过2℃, 具有很好的实际应用价值; 而最高路面温度模型在一定程度上模拟结果偏差较大,实际应用中需进行适当修订。 相似文献