共查询到20条相似文献，搜索用时 78 毫秒
1.
2.
《中国气象科学研究院年报》2001,(1)
After the open bidding and specialist appraisal, the project is undertaken jointly by the Institute of Plant Protection of the Chinese Academy of Agricultural Science, the Institute of Plant Protection of the Sichuan Province Academy of Agricultural Science, the Chinese Agricultural University, the Research Institute of Forest Protection of the Forestry Academy of China, the Chinese Forest University, the Chinese Academy of Meteorological Sciences, and the Research Institute of Agrometeorology of the Chinese Academy of Agricultural Science. The project (Project No: 2001BA509B, including 15 subprojects), is organized 相似文献
3.
Interannual and Interdecadal Variations in Atmospheric Circulation Factors and Rainfall in China and Their Relationship 总被引：4，自引：0，他引：4
Wavelet analysis is used to study the interannual and interdecadal variations of rainfall in China and atmospheric circulation factors, including the key atmospheric oscillations, W, C, E patterns and subtropical high. Regression analysis and correlation analysis are both used to study the relationship of atmospheric circulation factors and China rainfall on different time scale and spatial scale. The results are as follows: (1) The variations of atmospheric circulation and rainfall in China are characterized by interannual and interdecadal scales. The variations of atmospheric circulation and rainfall are composed of interannual and interdecadal variations. It is necessary to separate those two time scales when climate changes and forecast are studied. (2) The variations of China rainfall are due to the interaction of multi-factors rather than single factors. The marked factors which influence the interannual and interdecadal variations are various. Subtropical high is one of the marked factors which influence interannual variations of rainfall, while AO, NAO, and NPO are one of the marked factors which influence interdecadal variations of rainfall. (3) The longer the time scale is, and the larger the spatial scale is, and the more remarkable the relationships between atmospheric circulation and rainfall are. 相似文献
4.
Global climate change and variability and its influence on Alpine climate — concepts and observations 总被引：1，自引：0，他引：1
H. Wanner R. Rickli E. Salvisberg C. Schmutz M. Schüepp 《Theoretical and Applied Climatology》1997,58(3-4):221-243
Summary The paper discusses annual to decadal climate variability and change in the European Alps by utilizing the procedure of synoptic downscaling, i.e. it investigates the influence of global to continental scale synoptic structures and processes on the regional climate of the Alps. The European Alps lie to the southeast and under the right exit zone of the southwest-northeast oriented axis of the polar front jet over the North Atlantic ocean, in a transition zone between the Azores high and Icelandic low, between oceanic and continental and between Mediterranean and North Atlantic climates. Together with complex topographically induced phenomena like lee cyclogenesis, orographic precipitation, strong downslope winds and thermotopographical circulation systems, this transitional position makes climate studies in the Alps even more interesting. Only a minor correlation can be observed between global climate variability and Alpine climate. In contrast, the Alpine climate is strongly related to processes over the North Atlantic ocean and its sea ice system (e.g. it has a high correlation with the North Atlantic Oscillation and the dynamics and position of the Icelandic low), an area with a rather low climate prediction potential.Since the early 1970's (or just after the Great Salinity Anomaly in the North Atlantic Ocean) the intensification of the wintertime westerly jet over the North Atlantic area led to a noticeable northwest-southeast mass transport in the exit area of the jet over Central Europe, leading to pressure and temperature rises and an increase in the amount of precipitation. There is a question over whether this phenomenon is a consequence of natural climate variability or the beginning of an anthropogenic climate change.With 16 Figures 相似文献
5.
Eurasian Snow Conditions and Summer Monsoon Rainfall over South and Southeast Asia： Assessment and Comparison 总被引：2，自引：0，他引：2
This study reveals the complex nature of the connection between Eurasian snow and the following summer season＇s monsoon rainfall by using four different indicators of snow conditions and correlating each of them to summer monsoon rainfall. Using 46 years of historical records of mean winter snow depth, maximum snow depth, and snow starting dates, and 27 years of snow area coverage from remote sensing observations over Eurasia, the authors found diverse correlation patterns between snow conditions and the following warm season＇s rainfall over South and Southeast Asia. Some of the results contradict the well-known inverse relationships between snow and the summer monsoon. This study provides an easy comparison of results in that it shows the connections between Eurasian snow and monsoon rainfall by using different Eurasian snow indicators based on the best available historical records without discrimination of regional variations in snow conditions. 相似文献
6.
Air,Water and Soil Environmental Pollution and Regulation Mechanisms in Beijing and Its Ambient Area
《中国气象科学研究院年报》2001,(1)
1 Physical and Chemical Structural Characteristics of Urban ABLObtained preliminarily the atmospheric dynamic structure of the urban ABL: Urban heat island and urban wind, the zero-plane displacement and roughness of urban building blocks, the distribution and dynamic and thermal impacts of urban fog. In the aspect of city-scale simulation research, the effect of the topography around the outskirts of Beijing on the urban wind field and the effect of buildings on the urban atmospheric circulation are studied. The possible influencing mechanisms of the U-shaped mountains to the west and north of Beijing on the daily variation of the urban wind field, and the formation, transport and cumulation of urban pollutants are analyzed and some distribution charts are obtained. 相似文献
7.
Extreme weather events and their consequential impacts have been a key feature of the climate in recent years in many parts of the world, with many partly attributed to ongoing global-scale warming. The past year, 2022, has been no exception,with further records being broken. The year was marked by unprecedented heatwaves and droughts with highly unusual spatial extent, duration and intensity, with one measure indicating an aggregated and overall intensity of extreme heat events worldwide not se... 相似文献
8.
9.
10.
It is well known that retrieval of parameters is usually ill-posed and highly nonlinear, so parameter retrieval problems are very difficult. There are still many important theoretical issues under research, although great success has been achieved in data assimilation in meteorology and oceanography. This paper reviews the recent research on parameter retrieval, especially that of the authors. First, some concepts and issues of parameter retrieval are introduced and the state-of-the-art parameter retrieval technology in meteorology and oceanography is reviewed briefly, and then atmospheric and oceanic parameters are retrieved using the variational data assimilation method combined with the regularization techniques in four examples： retrieval of the vertical eddy diffusion coefficient; of the turbulivity of the atmospheric boundary layer; of wind from Doppler radar data, and of the physical process parameters. Model parameter retrieval with global and local observations is also introduced. 相似文献
11.
12.
Jaak Jaagus Agrita Briede Egidijus Rimkus Kalle Remm 《Theoretical and Applied Climatology》2014,118(1-2):57-68
Spatial distribution and trends in mean and absolute maximum and minimum temperatures and in the diurnal temperature range were analysed at 47 stations in the eastern Baltic region (Lithuania, Latvia and Estonia) during 1951–2010. Dependence of the studied variables on geographical factors (latitude, the Baltic Sea, land elevation) is discussed. Statistically significant increasing trends in maximum and minimum temperatures were detected for March, April, July, August and annual values. At the majority of stations, the increase was detected also in February and May in case of maximum temperature and in January and May in case of minimum temperature. Warming was slightly higher in the northern part of the study area, i.e. in Estonia. Trends in the diurnal temperature range differ seasonally. The highest increasing trend revealed in April and, at some stations, also in May, July and August. Negative and mostly insignificant changes have occurred in January, February, March and June. The annual temperature range has not changed. 相似文献
13.
《气象研究与应用》1981,(3)
All weather phenomena are associated in one form or another withheat or the absence of heat or the change in heat.Therefore,the man-ner of heating the air must be considered early in the study of how theair behaves.The earth as a planet has virtually no heat of its own.There is a certain amount of internal heat,but this can be ignored entire-ly from the meteorological point of view.Also neglivity are the amountsof heat resulting from either friction or radioactivity.Practically,theeart's sole source of heat is the sun.The sun is the parent of the earh, 相似文献
14.
《中国气象科学研究院年报》2001,(1)
Theworking time of the project is from 2001 to 2002. The main advancements obtained in 2001 are as follows.Project allocation: The PRC Ministry of Science and Technology approved the project on 15 February 2001. The project allocation meeting was convened in Beijing from 20 to 23 March 2001. CAMS and 11 provincial meteorological bureaus in West China undertake jointly the project. 相似文献
15.
In this paper, Indian monsoon of 1980 and 1981 is analysed based on the seasonal and half-month averaged data of 850 hPa of ECMWF analysis. The results show that Indian monsoon is related to Somali jet, the low-latitude easterlies and the mid-latitude westerlies over southern Indian Ocean, which are associated with the stationary wave of Southern Hemisphere. The forces affecting on the low-level flow are diagnosed, which display the relationship between Indian monsoon and the associated low-level flow. 相似文献
16.
Dependence of Hurricane Intensity and Structures on Vertical Resolution and Time-Step Size 总被引：5，自引：0，他引：5
In view of the growing interests in the explicit modeling of clouds and precipitation, the effects of varying vertical resolution and time-step sizes on the 72-h explicit simulation of Hurricane Andrew (1992) are studied using the Pennsylvania State University/National Center for Atmospheric Research (PSU/NCAR) mesoscale model (i.e., MM5) with the finest grid size of 6 km. It is shown that changing vertical resolution and time-step size has significant effects on hurricane intensity and inner-core cloud/precipitation, but little impact on the hurricane track. In general, increasing vertical resolution tends to produce a deeper storm with lower central pressure and stronger three-dimensional winds, and more precipitation. Similar effects, but to a less extent, occur when the time-step size is reduced. It is found that increasing the low-level vertical resolution is more efficient in intensifying a hurricane, whereas changing the upper-level vertical resolution has little impact on the hurricane intensity. Moreover, the use of a thicker surface layer tends to produce higher maximum surface winds. It is concluded that the use of higher vertical resolution,a thin surface layer, and smaller time-step sizes, along with higher horizontal resolution, is desirable to model more realistically the intensity and inner-core structures and evolution of tropical storms as well as the other convectively driven weather systems. 相似文献
17.
By use of the two-layer adiabatic globe spectral model and the zonally averaged climatic data of winter season as initial values, 10-day integrations are carried out based on three kinds of model topography (i.e., (1) the averaged topography; (2) the envelope topography; (3) the modified envelope topography). The results show that the orography of the Northern Hemisphere plays an important role in the simulation of large-scale weather patterns in winter season. The simulation based on the envelope topography developed by Wallace et al. has some improvements in the Rocky Mountains area. But this scheme causes very serious horizontal expansion around the Tibetan Plateau (hereafter referred to as the TV). A modified envelope topography scheme has been worked out that increases the slope of the TP by decreasing the horizontal expansion while keeping the maximum altitude. The results show some improvements of the scheme around the TP. By analysis of the mechanical effects of the large-scale orography on the 相似文献
18.
Dust sediments collected from 1995 to 1998 in Beijing, Dunhuang, Inner Mongolia, Kashi, the Kunlun Mountains, Lanzhou, Ningxia, the Taklimakan Desert, and Xi‘an, China, were characterized in terms of their physical, chemical, and mineralogical properties. Most aerosols and dust analysed ranged in texture from silty clay to clay loam. Their median particle diameters (Mds) generally ranged between 5 to 63μm,coinciding with those of loess from central China and the finest sand from northwestern China. The dust sediments were characterized by a predominance of SiO2 and Al2O3, followed by K2O. Their SiO2/Al2O3and K2O/SiO2 molar ratios ranged from 5.17 to 8.43 and from 0.009 to 0.0368, respectively. The mass concentration spectrum during a dust storm showed a single peak, rather than the triple peak generally observed under clear sky conditions. The dominant minerals were chlorite, illite, calcite, and dolomite.These physical, chemical, and mineralogical properties were consistent with those of aeolian soils and loess in western and central China. The results suggest that aerosols and fine-gained fractions of dust sediments collected in northern China are mainly composed of soil material transported from the arid and semiarid regions of China and Mongolia by prevailing winds. The rate of deposition and properties of dust falling on eastern China were strongly influenced by meteorological conditions, season, latitude, longitude, and altitude of the sampling sites. 相似文献
19.
Daily and monthly total precipitation of 155 synoptic stations with relatively regular distribution over Iran, covering the 1990–2014 period, were used to investigate the spatial pattern of precipitation seasonality and regimes over Iran, using a set of precipitation seasonality indices. The results suggest a strong agreement between the indices computed at monthly time scale. The result also shows a latitudinal decreasing gradient from the lower index values in the north to the highest values in the south of Iran, suggesting a strong negative relationship between the latitude and the indices. A weak but statistically significant association was also found between the indices and the longitude, showing a gradual west-east contrast between the mountainous western Iran and the central-eastern lowlands and deserts of the country. The spatial patterns of the indices well agree in revealing different precipitation regimes in Iran, in spite of the observed discrepancies in their areal extent of the regions identified. All the indices characterized northern Iran by a precipitation regime having a moderate seasonality, while the mountainous areas of the western and northern Iran are featured by a marked precipitation regime possessing a longer dry season. However, the most seasonal precipitation regime with the longest dry period describes the southern country and some spot areas of the central-eastern Iran. The spatial distribution of the seasonal precipitation regimes and the month and season of maximum precipitation amounts across Iran was also identified, suggesting that from the 24 possible precipitation regimes over the globe, eight were found in Iran, from which a precipitation regime with the highest precipitation amount in winter, followed by autumn, spring, and summer characterized most parts of the country. January and JFM were also found as the month and season of maximum precipitation in a majority of stations distributed over Iran, respectively. The precipitation concentration index (DPCI) computed using daily precipitation data ranges between 0.56 and 0.76 across the country; nonetheless, the values between 0.64 and 0.70 characterized a majority of stations distributed over most parts of Iran. Contrarily to the indices computed at monthly time scale, the DPCI does not show a clear latitudinal pattern over the country. The Mann–Kendal trend test and the Sen slope estimator were applied to the computed indices relative to 16 stations with the longest and complete precipitation records during 1951–2014 time period. The indices time series showed no significant trend in the majority of the stations, indicating that the precipitation regimes of the studied stations did not change over 1951–2014 period. 相似文献
20.
《中国气象科学研究院年报》2001,(1)
Several observational experiments on the urban ABL atmospheric dynamic and chemical structure, the 3D structure of atmospheric pollutants in the urban ABL and the interaction of the urban ABL atmospheric dynamic-chemical processes were conducted, focused on the Beijing urban ABL physical and chemical structural characteristics and variation regularities. A great amount of valuable data was obtained and a comprehensive database of the urban ABL environment was established preliminarily, based on which the data processing and numerical simulation are in progress. 相似文献