A method of characterizing the thermal relations in mountainous areas / the lower Beskid range in the Polish Carpathians as example     

M. Hess  T. Niedwied  B. Obrbska-Starkelowa 《GeoJournal》1984,8(3):251-257

The method discussed in the present paper permits the determination in detail of the mesoclimatic conditions on the basis of standard data provided by a network of a measurement stations. The passage from the data available at certain points and obtained from meteorological stations to spatial conceptions leads along the determination of the relationships between the altitude, various forms of the relief, and the thermal indices of climate. Resulting from these data, the duration of the frostless period is a sensitive index in the scale of mesoclimate, besides all the other indices connected with the minimum air temperatures. The nomographs applied by the authors make it possible to construct detailed climatic maps, which — with the maps of other elements of the geographical environment — form a basis for the elaboration e.g. an agrocological map of habitats. Presented method of the evaluation of climate conditions can be applied to all mountain territories, in which a network of measurement stations enables the determination of the interdependencies between the chosen thermal parameters and the altitude, and the distinction of the impact of the convex and concave forms.  相似文献   

“00.7”北京特大暴雨模拟中气象资料同化作用的评估   总被引：18，自引：0，他引：18  

张朝林  Kuo Ying Hw  范水勇  仲跻芹 《气象学报》2005,63(6):922-932

针对2000年7月4～5日北京地区的一次特大暴雨过程(24 h降水量达240 mm),文中利用MM5/WRF三维变分系统和MM5非静力模式,对此次特大暴雨过程中的各种气象监测资料(地基GPS大气柱水汽含量、常规探空、高空测风、地面常规观测和地面自动气象站)的同化作用通过观测系统数值试验进行了评估.结果表明与传统的客观分析方案相比较,MM5/WRF三维变分同化系统可直接引入非常规地基GPS大气柱水汽含量监测资料,提供更好的大气初始分析场.在三维变分同化方案下,各种大气监测资料均对改进此次特大暴雨模拟有不同程度的贡献,其中,常规探空和高空测风监测资料对改进预报结果的影响最大,地面常规观测和地面自动气象站观测资料作用次之,地基GPS大气柱水汽含量资料在与其他大气监测资料相互优势互补后,可很好地改善模式大气的分析质量,通过三维变分同化技术在区域数值天气预报模式初始场中引入地基GPS大气水汽监测网资料,使此次强降水个例的6 h和24 h测站降水预报的TS评分值在1,5,10和20 mm预报检验阈值下分别提高了1%～8%.研究结果对利用三维变分数值系统,评估气象监测网资料在改进高影响天气事件预报中的作用有借鉴意义.  相似文献   

Carbon Sequestration in Arable Soils is Likely to Increase Nitrous Oxide Emissions,Offsetting Reductions in Climate Radiative Forcing   总被引：5，自引：0，他引：5  

Changsheng?Li  Steve?FrolkingEmail author  Klaus?Butterbach-Bahl 《Climatic change》2005,72(3):321-338

Strategies for mitigating the increasing concentration of carbon dioxide (CO₂) in the atmosphere include sequestering carbon (C) in soils and vegetation of terrestrial ecosystems. Carbon and nitrogen (N) move through terrestrial ecosystems in coupled biogeochemical cycles, and increasing C stocks in soils and vegetation will have an impact on the N cycle. We conducted simulations with a biogeochemical model to evaluate the impact of different cropland management strategies on the coupled cycles of C and N, with special emphasis on C-sequestration and emission of the greenhouse gases methane (CH₄) and nitrous oxide (N₂O). Reduced tillage, enhanced crop residue incorporation, and farmyard manure application each increased soil C-sequestration, increased N₂O emissions, and had little effect on CH₄ uptake. Over 20 years, increases in N₂O emissions, which were converted into CO₂-equivalent emissions with 100-year global warming potential multipliers, offset 75–310% of the carbon sequestered, depending on the scenario. Quantification of these types of biogeochemical interactions must be incorporated into assessment frameworks and trading mechanisms to accurately evaluate the value of agricultural systems in strategies for climate protection.  相似文献   

ENERGY BALANCE IN 40－50 DAY PERIODIC OSCILLATION OVER THE ASIAN SUMMER MONSOON REGION DURING THE 1979 SUMMER     

He Jinhai  T. Murakami  T. Nakazawa 《大气科学进展》1987,4(1):66-73

Based on calculations of data from FGGE Level III b, a discussion is made of the energy balance in the 40－50 day periodic oscillation over the Asian monsoon region during the 1979 summer. It is found that the main source of 40－50 day periodic perturbation is the monsoon region extending from central South Asia to Southeast Asia. In the upper layer over the North Pacific subtropical area (10－20oN, 150oE－150oW) pres-sure work turns into kinetic energy that maintains 40－50 day periodic perturbation associated with the variation in position and intensity of the mid-Pacific trough. The mean energy budget in the three-dimensional space (0－30oE, 30oE－150oW, 100－1000 hPa) indicates that the 40－50 day periodic perturbation transports kinetic energy to a seasonal mean and a transient perturbation wind field.  相似文献   

    

Peng Yongqing  Zhu Yufeng  Yan Shaojin 《大气科学进展》1994,11(3):277-284

This paper concerns the reconstruction of a dynamic system based on phase space continuation of monthly mean temperature 1D time series and the assumption that the equation for the time-varying evolution of phase-space state variables contains linear and nonlinear quadratic terms, followed by the fitting of the dataset subjected to continuation so as to get, by the least square method, the coefficients of the terms, of which those of greater variance contribution are retained for use. Results show that the obtained low-order system may be used to describe nonlinear properties of the short range climate variation shown by monthly mean temperature series.  相似文献   

Gap flow measurements during the Mesoscale Alpine Programme     

G. J. Mayr  L. Armi  S. Arnold  R. M. Banta  L. S. Darby  D. D. Durran  C. Flamant  S. Gaberšek  A. Gohm  R. Mayr  S. Mobbs  L. B. Nance  I. Vergeiner  J. Vergeiner  C. D. Whiteman 《Meteorology and Atmospheric Physics》2004,86(1-2):99-119

Summary The lowest pass through the Alpine crest, the Brenner Pass, was heavily instrumented with ground-based and air-borne in-situ and remote sensors during the Special Observation Period (SOP) of the Mesoscale Alpine Programme (MAP) in the fall of 1999 to study gap flow. The main objectives were to study the combined effects of changes of terrain height and changes of width in altering the flow characteristics, to investigate the coupling of the gap flow to the flow aloft, and to provide high-density measurements in the along- and cross-gap directions.Gap flows occurred during one third of the 70-day SOP, a frequency above the long term average. Gap flows took place with and without accompanying cross-barrier flow and with and without a capping inversion. A case study demonstrates the hydraulic jump-like features that occurred in gap flow on 30 October 1999 and illustrates the types of data available for further analyses.  相似文献   

Zonal propagation of kinetic energy and convection in the South China Sea and Indian monsoon regions in boreal summer   总被引：7，自引：0，他引：7  

CHEN Longxun  GAO Hui  HE Jinhai  TAO Shiyan & JIN Zuhui .Chinese Academy of Meteorological Sciences  Beijing  China  .Nanjing Institute of Meteorology  Nanjing  China  .Institute of Atmospheric Physics  Chinese Academy of Sciences  Beijing  China 《中国科学D辑(英文版)》2004,47(12):1076-1084

As early as in the 1980s, Chinese scientists hadfirst proposed that there exits two summer monsoonsystems in Asia, namely the East Asian summer mon-soon (EASM) and the Indian summer monsoon(ISM)[1-4]. The two monsoon systems are quite dif-ferent in characteristics. Since then, such issue andconclusion had been documented and approved by alot of studies in the past two decades, and was appliedin the guideline of the South China Sea summer mon-soon experiment (SCSMEX), which was undertak…  相似文献   

NO<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript> change over China and its influences   总被引：2，自引：0，他引：2  

LIU Yu  I. S. A. ISAKSEN  J. K. SUNDET  HE Jinhai  YAN Peng 《大气科学进展》2004,21(1):132-140

A 3-D chemical transport model (OSLO CTM2) is used to investigate the impact of the increase of NOx emission over China. The model is capable to reproduce basically the seasonal variation of surface NOx and ozone over eastern China. NOx emission data and observations reveal that NOx over eastern China increases quite quickly with the economic development of China. Model results indicate that NOx concentration over eastern China increasingly rises with the increase of NOx emission over China, and accelerates to increase in winter. When the NOx emission increases from 1995 to its double, the ratio of NO2/NOx abruptly drops in winter over northern China. Ozone at the surface decreases in winter with the continual enhancement of the NOx level over eastern China, but increases over southern China in summertime. It is noticeable that peak ozone over northern China increases in summer although mean ozone changes little. In summer, ozone increases in the free troposphere dominantly below 500 hPa.Moreover, the increases of total ozone over eastern China are proportional to the increases of NOx emission.In a word, the model results suggest that the relationship between NOx and ozone at the surface would change with NOx increase.  相似文献   

CHARACTERISTICS OF CONVECTIVE ACTIVITIES OVER ASIAN-AUSTRALIAN “LAND BRIDGE” REAS AND ITS POSSIBLE FACTORS^*          下载免费PDF全文

WANG Lijuan  HE Jinhai  GUAN Zhaoyong 《Acta Meteorologica Sinica》2004,18(4):441-454

Based on TBB data from GMS of Japan,NCEP/NCAR reanalysis data and precipitation data from CMAP(CPC Merged Analysis of Precipitation),an investigation is carried out of seasonal changes of precipitation and convection over Asian-Australian "land bridge" areas and its possible factors.The results show that the precipitation and convection over Sumatra take on clearly seasonal changes with abundant (less) rainfall in winter (summer).The convection over Sumatra moves northwestward rapidly along "land bridge" in the late-April and the early-May (the 25th pentad) and the rainfall shows similar variations.It is the accelerating of the convection moving that affects directly the subsequent enhancement of the convection over Indo-China Peninsula (ICP) area followed by the rupture of the subtropical high (SH) bands in this region leading to South China Sea (SCS) summer monsoon establishment.The zonal wind at lower troposphere in the equatorial Indian Ocean and the cross-equatorial flow in 105°E are the main factors associated with the accelerating of the convection moving northwestward along "land bridge".The further study suggests that the intensity of Sumatra convection has a close relation to the SST:when the central-east equatorial Pacific SST is warmer (colder),i.e.E1 Nino (La Nina) events,the SST in West Pacific warm pool is colder (warmer),Sumatra convection is weaker (stronger).  相似文献   

Variability of seasonal-mean fields arising from intraseasonal variability. part 2, application to nh winter circulations     

C.?S.?FrederiksenEmail author  X.?Zheng 《Climate Dynamics》2004,23(2):193-206

A method for studying patterns of interannual variability arising from intraseasonal variability has been applied to the extratropical Northern Hemisphere wintertime 500 hPa geopotential height, using data from the NCEP-NCAR. These patterns describe the effects predominantly of intraseasonal variability and blocking. Removing this component from the sample interannual covariance matrix, one can define a residual, or slow, component of interannual variability that is more closely related to external forcings and very slowly varying (interannual/supra-annual) internal dynamics. For the Northern Hemisphere NCEP-NCAR reanalysis data, there are considerable differences between the intraseasonal patterns and the total patterns. The intraseasonal patterns are more spatially localized and more closely related to known intraseasonal variability, especially blocking events and the Madden-Julian Oscillation. Although the slow patterns and the total patterns look similar, they have some important differences. The slow patterns are more closely related to the slowly varying external forcing and very low-frequency internal dynamics than those derived by the sample covariance matrix. This is evidenced by the fact that the principal component time series of the slow patterns have a larger proportion of variability related to these factors. Where tropical SST forcing is important, the slow patterns tended to be more highly correlated with the interannual variations in the forcing. Three slow modes, related to the Tropical Northern Hemisphere, East Atlantic and Western Pacific teleconnections, are all significantly related to tropical SST variability associated predominantly with the El Nino-Southern Oscillation, in the case of the first two, and Indian Ocean variability, in the third case. The derived slow patterns and intraseasonal patterns may help to better understand the long-range predictability, uncertainty, and forcing of climate variables, for the wintertime circulation.  相似文献