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1.
该文运用统计方法对安顺市近45 a夏旱情况进行了统计分析,得出各种夏旱出现的大致机率,并经过初步分析和应用他人对贵州夏旱的科研成果,给出安顺市夏旱的环流背景和主要影响系统,对今后夏旱的预报工作有一定借鉴作用。  相似文献   

2.
铜仁地区是贵州省夏旱最严重的地区之一 ,本文按铜仁地区夏旱出现的先后区分出洗手干 ( 6月 )和伏旱 ( 7~ 8月 )两类夏旱天气 ,并据此分别对两类夏旱的 10 0hPa环流异常特征作了较为深入的讨论 ,以进一步揭示形成我区夏旱的大气环流演变规律。  相似文献   

3.
贵州省夏旱特征及分区研究   总被引:12,自引:1,他引:12  
刘雪梅  宋国强 《高原气象》1997,16(3):292-299
干旱是贵州省的主要气象灾害之一。应用夏旱强度指数和修正的帕尔默指数及降雨量等其它指标,对贵族夏旱的类型、发生频率、持续时间、地区分布、易发生时段和垂直变化等特征作了系统的研究,总结出贵州夏旱的主要特征并进行了夏旱分区。  相似文献   

4.
吴哲红 《贵州气象》1999,23(1):16-17,32
统计分析了安顺1955-1996年夏旱及其天气环流背景,并计算了夏旱指数,指出安顺夏旱与中高纯及副热带环流密切相关。并提出了统计分析过程中遇到的两个问题。  相似文献   

5.
铜仁地区是贵州省夏旱最严重的地区之一,本文按铜仁地区夏旱出现的先后区分出洗后干(6月)和伏旱(7~8月)两类夏天气,并据此分别对两类夏旱的100hPa环流异常特征作为较为深入的讨论,以进一步揭示形成我区夏旱的大气环流演变规律。  相似文献   

6.
许炳南  张弼州 《贵州气象》1993,17(4):15-23,25
本文利用全省现有87个气象台站1951~1991年雨量资料,对夏旱的地区分布,年际变化、区域性夏旱时段、较重与较轻夏旱年等统计特征进行了系统的分析研究,较全面地总结了夏旱的气候特征。  相似文献   

7.
该文利用贵州境内1961—2015年84个站点的气象观测数据,得出贵州近55 a来具有气温增高、年总降雨量在平均值附近波动的气候变化特征。在此气候变化背景下,根据贵州省地方干旱标准(DB52_T_1030-2015),利用夏旱强度指数公式、小波分析,M-K检验等方法,对贵州夏旱变化特征进行分析。结果表明:近55 a来,夏旱强度指数随时间在平均值附近波动,夏旱强度指数多年平均值为132.35,达到中旱级别,且每年均出现不同程度的夏旱。2005年为夏旱强度指数的突变年,突变年后,多年平均值较突变前升高16;突变发生后,夏旱强度指数明显增强,指数大于145的区域明显增大,介于101~115之间的区域明显减少。夏旱强度指数具有20~21 a的主周期特征,且具有从西部到东部逐渐变强、东部重西部轻的特征。  相似文献   

8.
本文应用夏旱强度指数和修正的帕默尔指数对贵州夏旱的发生频率,持续时间,干旱类型,地区分布进行详细分析,得出贵州夏旱的基本规律和主要特点,提出了减轻夏时造成的损失应采取的对策和措施。  相似文献   

9.
重庆市夏季干旱时空分布特征研究   总被引:3,自引:1,他引:3  
根据有关干旱计算方法,对重庆市34个气象台站40年来夏旱发生频率,强度的时空分布规律,类型划分,区域特征及区域性夏旱发生频率,阶段变化特征等进行了系统地分析,研究,揭示了重庆市夏旱的发生规律。  相似文献   

10.
姜修萍 《贵州气象》2005,29(2):26-27
在夏旱时段分级标准的基础上,对修文县夏旱时空分布规律进行系统分析,为防旱抗旱提供参考依据。  相似文献   

11.
This paper analyzes the influence of flaw polynyas of the seas of the Siberian shelf on the formation of ice conditions in summer based on the ten-day data on the areas of flaw polynyas for 1978–2002 obtained by satellite image processing. The results of forecasts of summer ice conditions in the seas of the Siberian shelf are presented. The correspondence between the forecasts and observed data is 94.7% on average. The interrelation of atmospheric and ice processes is shown for the case when winter atmospheric processes determine ice conditions for the following summer and fall.  相似文献   

12.
Different means to estimate changes in fire-hazard conditions in the Russian forests are analyzed in connection with climate changes. Climate data are considered as based upon standard observations and calculated characteristics obtained from the atmosphere-ocean general circulation models. Space distributions are calculated of changes in extreme conditions for fire hazard at the end of the 21st century, as compared with those at the end of the 20th century.  相似文献   

13.
Over the past three decades, the drawdown of atmospheric CO2 in vegetation and soil has fueled net ecosystem production (NEP). Here, a global land-surface model (CABLE) is used to estimate the trend in NEP and its response to atmospheric CO2, climate change, biological nitrogen (N) fixation, and N deposition under future conditions from 2031 to 2100 in the Belt and Road region. The trend of NEP simulated by CABLE decreases from 0.015 Pg carbon (C) yr?2 under present conditions (1936–2005) to ?0.023 Pg C yr?2 under future conditions. In contrast, the trend in NEP of the CMIP6 ensemble changes from 0.014 Pg C yr?2 under present conditions to ?0.009 Pg C yr?2 under future conditions. This suggests that the trend in the C sink for the Belt and Road region will likely decline in the future. The significant difference in the NEP trend between present and future conditions is mainly caused by the difference in the impact of climate change on NEP. Considering the responses of soil respiration (RH) or net primary production (NPP) to surface air temperature, the trend in surface air temperature changes from0.01°C yr?1 under present conditions to 0.05°C yr?1 under future conditions. CABLE simulates a greater response of RH to surface temperature than that of NPP under future conditions, which causes a decreasing trend in NEP. In addition, the greater decreasing trend in NEP under future conditions indicates that the C–climate–N interaction at the regional scale should be considered. It is important to estimate the direction and magnitude of C sinks under the C neutrality target.摘要目前, 在区域尺度, NEP趋势变化的强度和影响机制还存在很大的不确定性. 针对这一问题, 我们选取了一带一路覆盖的区域为研究对象, 基于全球陆面模式 (CABLE)和第六次国际耦合模式比较计划 (CMIP6), 评估了历史和未来NEP趋势的变化, 分析了影响的机制. 从过去到未来, CABLE结果表明NEP的趋势从 0.015 Pg C yr?2 减少到 –0.023 Pg C yr?2; CMIP6结果为从0.014 Pg C yr?2转变为–0.009 Pg C yr?2. 气候变化是引起这一变化的主因. 我们的研究结果强调了碳-气候-氮相互作用的重要性, 这对碳中和目标下碳汇潜力的准确估算尤为重要.  相似文献   

14.
The Thornthwaite moisture index is useful as an indicator of the supply of water in an area relative to the demand under prevailing climatic conditions. This study examines the effects of long-term changes in climate (temperature and precipitation) on the Thornthwaite moisture index in the Delaware River basin. Temperature and precipitation estimates for doubled-CO2 conditions derived from three general circulation models (GCMs) are used to study the response of the moisture index for steady-state doubled-CO2 conditions and for gradual changes from present to doubled-CO2 conditions.Results of the study indicate that temperature and precipitation under doubled-CO2 conditions will cause the Thornthwaite moisture index to decrease, implying significantly drier conditions in the Delaware River basin than currently exist. The amount of decrease depends, however, on the GCM climatic-change scenario used. The results also indicate that future changes in the moisture index will be partly masked by natural year-to-year variability in temperature and precipitation.  相似文献   

15.
Poor daytime and night-time micrometeorological conditions are issues that influence the quality of environmental conditions and can undermine a comfortable human lifestyle. The sky view factor (SVF) is one of the essential physical parameters used to assess the micrometeorological conditions and thermal comfort levels within city streets. The position of the visible sky relative to the path of the sun, in the cardinal and ordinal directions, has not been widely discerned as a parameter that could have an impact on the micrometeorological conditions of urban streets. To investigate this parameter, different urban streets that have a similar SVF value but diverse positions of visible sky were proposed in different street directions intersecting with the path of the sun, namely N–S, NE–SW and NW–SE. The effects of daytime and night-time micrometeorological variables and human thermal comfort variables on the street were investigated by applying ENVI-met V3.1 Beta software. The results show that the position of the visible sky has a greater influence on the street’s meteorological and human thermal comfort conditions than the SVF value. It has the ability to maximise or minimise the mean radiation temperature (Tmrt, °C) and the physiological equivalent temperature (PET, °C) at street level. However, the visible sky positioned to the zenith in a NE–SW or N–S street direction and to the SW of a NW–SE street direction achieves the best daytime micrometeorological and thermal comfort conditions. Alternatively, the visible sky positioned to the NE for a NW–SE street direction, to the NW and the zenith for a NE–SW street direction and to the zenith for a N–S street direction reduces the night-time air temperature (Ta, °C). Therefore, SVF and the position of the visible sky relative to the sun’s trajectory, in the cardinal and ordinal directions, must be considered during urban street planning to better understand the resultant micrometeorological and human thermal comfort conditions.  相似文献   

16.
A large set of tower data was used to identify the gap that separates small-scale turbulence and mesoscale structures in the cospectra of surface fluxes. The cospectra were obtained using a multi-resolution decomposition algorithm. The gap time scale τ g was found by fitting a fifth-order polynomial to the cospectra and identifying special points occurring after the peak at small scales. In unstable conditions (day) τ g was found to fall as the mean wind speed increased, while no such dependence was observed in stable conditions (night). The gap scale was found to change very weakly with stability both in moderately stable and moderately unstable conditions, with a sharp drop from about 1100 to 250 s occurring in near-neutral conditions. The vertical fluxes computed at different averaging intervals were found to correlate exceptionally well with each other, the scatter being somewhat larger during the night. Although considerable discrepancy may occur for individual records, when averaged over 10 months, the difference in the flux estimated at 7 to 109 min intervals never exceeded 4%, which is comparable or less than the instrumental error.  相似文献   

17.
B. G. Hunt 《Climatic change》2009,97(3-4):389-407
A multi-millennial simulation with the CSIRO Mark 2 coupled global climatic model has been used to determine whether climatic conditions approximate to those experienced by the medieval Norse settlers in Greenland could be identified. The aim of this analysis was to see whether such conditions could be replicated by the natural climatic variability in this unforced simulation, in order to counteract claims that the current observed global warming is merely another example of this type of climatic regime. This view has been expressed in the media in an attempt to refute the existence of a CO2-induced global warming. A 291-year period of above-average temperature followed by a 41-year cooler period were identified in one millennium of the simulation, and subsequently used as an analogue of conditions representative of the time of the Norse settlements. Considerable interannual variability existed in both these periods, but with noticeable positive and negative surface temperature anomalies in the warm and cold periods respectively. Thus the warm period was not a time of uniform benign conditions. Above-average precipitation was also associated with the warm period, and these climatic conditions would have enhanced pasture growth and hay production (the only crop the Norse produced) thereby sustaining the livelihood of the Norse Greenlanders. The climatic conditions associated with the cold period in the model were probably sufficient to limit the survival prospects of the settlers, especially when other, probably more critical, deleterious factors are taken into account. The temperature anomalies replicated in the simulation are similar to the limited proxy data, but may be smaller in magnitude: nevertheless they appear to be sufficiently large to have affected the viability of the Norse Greenlanders. After considering possible climatic mechanisms that could have contributed to these warm and cold periods it was concluded that they are simply a consequence of stochastic influences generated by nonlinear processes in the simulation. Thus this simulation provides no support for the contention that the current global warming is a manifestation of conditions prevailing during the Norse settlements in Greenland.  相似文献   

18.
2004年全球重大气候事件概述   总被引:1,自引:3,他引:1  
郭艳君  任福民 《气象》2005,31(4):32-34
2004年全球气候持续偏暖。年初,暴雪席卷欧洲多国,美国受到罕见大雪袭击,南亚和墨西哥遭遇低温严寒。北半球夏秋季,西太平洋、大西洋热带风暴活动频繁。日本、菲律宾和美国受灾严重。年内,非洲、亚洲部分国家发生严重干旱;同时,南亚、南美洲及非洲多国暴雨致洪。年内,欧洲伊比利亚半岛、日本和澳大利亚遭遇高温热浪。  相似文献   

19.
Agriculture appears to be one of the human activities most vulnerable to climatic changes due to its large dependence on environmental conditions. However, the diversity of Brazilian environmental conditions could be of great advantage to adapting this sector to new climatic conditions, which should be assessed as in this study on shifting Arabica coffee cultivation to the extreme south of the country. The methodology applied is the same the one used to define climatic risks in current productive regions of Brazil and their vulnerability to climatic change predicted by IPCC reports. The basic climatic parameters applied were frost probability and annual average temperature, since annual water deficit did not prove to be a restricting factor for Arabica coffee cultivation in the study area. The climatic conditions suitable for coffee production are: annual average temperature between 18??C and 22??C, annual water deficit less than 100?mm and frost probability (risk of lowest annual temperature less than 1??C) less than 25%. An area is said to have ??low climatic risks?? for coffee production when these three climatic conditions are met. Current climatic conditions were used and simulations of four temperature increases between 1??C and 4??C were also performed. The results indicated a substantial increase in the size of low climatic risks areas for the production of Arabica coffee in the extreme south of Brazil, mainly for mean temperature increases of 3??C in the study area in relation to present conditions. Increases of 2??C and 4??C were also favorable, but not as good as those obtained for 3??C. It should be underscored that areas with low climatic risks will be able to be found mainly in the extreme south of the study region, the border with Uruguay and North of Argentina.  相似文献   

20.
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