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1.
印度洋和南海海温与长江中下游旱涝 总被引：41，自引：10，他引：41
作者统计分析了1958～1999年42年长江中下游地区夏季5～8月旱涝事件的分布特征.结果表明,42年中旱涝月出现频次相等,但洪涝强度远大于干旱强度.对比分析旱涝月的环流异常和海温异常(SSTA)发现,南海地区SSTA和对流层低层经向风异常均与长江中下游旱涝显著相关,尤其正SSTA和涝月的关系更为密切,因此南海SSTA为我国长江中下游地区旱涝的一个强讯号.进一步分析发现,夏季南海SSTA与前春赤道南印度洋SSTA存在显著相关,可将其作为预报因子.最后得到的预报思路为:当前春赤道南印度洋海温异常偏暖,则夏季南海海温异常偏暖,南海低空出现异常偏南风,异常多的水汽向我国南方输送,长江中下游地区易涝;反之当前春南印度洋海温异常偏冷,夏季南海海温亦异常偏冷,南海低空出现异常偏北风,向北输送水汽偏少,长江中下游易旱. 相似文献
2.
异常情况下大风的记录和编发报 总被引：1，自引：1，他引：0
介绍自动站风向风速传感器的工作原理及风要素的采集方法,对自动气象站FJ.TXT文件中记录的大风数据与Z文件记录的极大风速及其出现时间不一致的原因进行分析,并提出正确记录和编发报的方法。 相似文献
3.
In this study, satellite-derived outgoing longwave radiation (OLR) and the reanalysis from the National Centers for Environmental
Prediction/National Center for Atmospheric Research are used as verification data in a study of intraseasonal variability
in the Goddard Laboratory for Atmospheres (GLA) and the United Kingdom Meteorological Office (UKMO) atmospheric general circulation
models. These models simulated the most realistic intraseasonal oscillations (IO) of the 15 Atmospheric Model Intercomparison
Project models previously analyzed. During the active phase of the intraseasonal oscillation, convection is observed to migrate
from the Indian Ocean to the western/central Pacific Ocean, and into the South Pacific Convergence Zone (SPCZ). The simulated
convection, particularly in the GLA model, is most realistic over the western/central Pacific Ocean and the SPCZ. In the reanalysis,
the baroclinic structure of the IO is evident in the eddy-stream function, and eastward migration of the anticyclone/cyclone
pairs occurs in conjunction with the eastward development of convection. Both the GLA and UKMO models exhibit a baroclinic
structure on intraseasonal time scales. The GLA model is more realistic than the UKMO model at simulating the eastward migration
of the anticyclone/cyclone pairs when the convection is active over the western/central Pacific. In the UKMO model, the main
heating is located off the equator, which contributes to the irregular structures seen in this model on intraseasonal time
scales. The maintenance and initiation of the intraseasonal oscillation has also been investigated. Analysis of the latent
heat flux indicates that evaporative wind feedback is not the dominant mechanism for promoting the eastward propagation of
the intraseasonal oscillation since evaporation to the west of the convection dominants. The data suggest a wave-CISK (conditional
instability of the secondkind) type mechanism, although the contribution by frictional convergence is not apparent. In the
GLA model, enhanced evaporation tends to develop in-place over the west Pacific warm pool, while in the UKMO simulation westward
propagation of enhanced evaporation is evident. It is suggested that lack of an interactive ocean may be associated with the
models systematic failure to simulate the eastward transition of convection from the Indian Ocean into the western Pacific
Ocean. This hypothesis is based upon the examination of observed sea surface temperature (SST) and its relationship to the
active phase of the intraseasonal oscillation, which indicates that the IO may evolve as a coupled ocean-atmosphere mode.
The eastward propagation of convection appears to be related to the gradient of SST, with above normal SST to the east of
the convection maintaining the eastward evolution, and decreasing SST near the western portion of the convective envelope
being associated with the cessation of convection.
Received: 13 September 1996/Accepted: 14 April 1997 相似文献
4.
G J Boer 《Climate Dynamics》1993,8(5):225-239
The increase in the vigor of the hydrological cycle simulated in a 2 × CO2 experiment with the Canadian Climate Centre general circulation model is smaller than that obtained by other models which have similar increases in mean surface temperature. The surface energy budget, which encompasses also the moisture budget for the oceans, is analyzed. Changes in the net radiative input to and sensible heat flux from the surface act to warm it. This is balanced, at the new equilibrium, by a change in the latent heat flux which acts to cool it. Although this same general behavior is seen in other models, the increase in radiative input to the surface in the CCC GCM is smaller than in other models while the change in the sensible heat flux is of similar size. As a consequence, the latent heat flux required for balance is smaller. The comparatively small increase in the net radiative input at the surface occurs because of a decrease in the solar component. On average the decrease in solar input in the tropical region outweighs the higher latitude increase associated with the snow/ice albedo feedback. The notable tropical decrease in solar input occurs because the albedo of the clouds increase enough in this region to outweigh a small decrease in cloud amount. The increase in cloud albedo in the warmer and moister tropical atmosphere is a consequence of the parameterized cloud optical properties in the model which play an important role in the regulation of the surface energy and moisture budgets. The results demonstrate some of the consequences of the negative feedback mechanism associated with increasing cloud albedo in the model. They also suggest that the simulated change in the vigor of the hydrological cycle is not a simple function of the average increase in surface temperature but is a consequence of all of the processes in the model which control the available energy at the surface as a function of latitude. 相似文献
5.
J. Lelieveld P. Hadjinicolaou E. Kostopoulou J. Chenoweth M. El Maayar C. Giannakopoulos C. Hannides M. A. Lange M. Tanarhte E. Tyrlis E. Xoplaki 《Climatic change》2012,114(3-4):667-687
The Eastern Mediterranean and the Middle East (EMME) are likely to be greatly affected by climate change, associated with increases in the frequency and intensity of droughts and hot weather conditions. Since the region is diverse and extreme climate conditions already common, the impacts will be disproportional. We have analyzed long-term meteorological datasets along with regional climate model projections for the 21st century, based on the intermediate IPCC SRES scenario A1B. This suggests a continual, gradual and relatively strong warming of about 3.5–7°C between the 1961–1990 reference period and the period 2070–2099. Daytime maximum temperatures appear to increase most rapidly in the northern part of the region, i.e. the Balkan Peninsula and Turkey. Hot summer conditions that rarely occurred in the reference period may become the norm by the middle and the end of the 21st century. Projected precipitation changes are quite variable. Annual precipitation is expected to decrease in the southern Europe – Turkey region and the Levant, whereas in the Arabian Gulf area it may increase. In the former region rainfall is actually expected to increase in winter, while decreasing in spring and summer, with a substantial increase of the number of days without rainfall. Anticipated regional impacts of climate change include heat stress, associated with poor air quality in the urban environment, and increasing scarcity of fresh water in the Levant. 相似文献
6.
本文综述了近几年来关于东亚冬季风变异特征和机理方面的研究,特别对平流层过程对东亚冬季风和气候异常的可能影响作了回顾和进一步分析.东亚冬季风的变异除了季风强弱变化外,还有东亚冬季风的路径变化;研究表明,前者往往对应全国气温一致的变化,而后者可以引起我国气温的南北反相振荡,并导致东亚冬季风变异存在南北两个子系统.此外,进入本世纪后,东亚冬季风的建立推迟,并且东亚冬季风在盛期明显减弱,但冬季风活动在早春比以往要更为活跃,这些变化与冬季气温南北反相变化也有密切的联系.进一步的分析揭示出东亚气温的南北反相变化是东亚冬季风变异的主要模态之一,而且它与平流层极涡强度密切相关.当异常的平流层极涡向下传播时,可以引起对流层低层北极涛动(AO)的异常以及西伯利亚高压的异常,并在东亚地区出现南北反相的温度变化.有关东亚冬季风变异的成因研究表明,上世纪70年代中后期以后,热带厄尔尼诺—南方涛动(ENSO)的影响变弱,而中高纬的北太平洋涛动(NPO)和乌拉尔地区阻塞强度的影响显著增强,相关研究还揭示了这些变化的原因.此外,东亚冬季风在1987年以后的持续减弱主要与准定常行星波活动年代际变化有关,行星波活动通过波流相互作用可以影响AO以及西伯利亚高压和阿留申低压,从而导致冬季风异常.最后,本文还讨论了太阳活动11年周期变化对东亚冬季气候异常的可能影响和过程. 相似文献
7.
8.
Three years (2008–2011) of direct current measurements from a mooring array deployed at the western Yucatan Channel (defined west of 85.6°W) and along the eastern Campeche Bank captured the main characteristics of the Yucatan and Loop Currents and the eddies associated with them. The array was deployed to provide upstream conditions in support of the Loop Current Dynamics Experiment. A substantial portion (60–80%) of the variance at the mooring sections is related to horizontal shifts of the currents due to meanders and eddies. Time-frequency analysis indicates that the velocity time-series are “event dominated”, with higher variability at low-frequencies (40–100 days or longer periods) but with a substantial contribution at higher frequencies (5–25 days periods) particularly strong from October to March. The vertical structure and time evolution of the eddy kinetic energy in a developing Campeche Bank cyclone suggest baroclinic instability dynamics are relevant for its development. Four Loop Current eddies (Cameron, Darwin, Ekman and Franklin) separated during 2008–2011. Ekman and Franklin were particularly dominated by a cyclone associated with a meander trough of the southward flowing branch of the Loop Current (Donohue et al., 2016a, Donohue et al., 2016b) and weaker Campeche Bank cyclones. For Cameron and Darwin, Campeche Bank cyclonic anomalies appear to be nearly as strong as the ones coming from the eastern side of the Loop Current. Eastward shifts of the Yucatan and Loop Currents observed over the sections appear to be linked to vorticity perturbations propagating from the Caribbean and precede several eddy detachments; their significance for the generation of Campeche Bank cyclones and eddy shedding remains to be determined.Time-series of Yucatan Current transport, vorticity fluctuations and Loop Current northward extension during the 3 deployment periods only depict positive correlation in two of them. Given the wide spectrum of variability, much more data are required to determine if a statistically robust relation exists among these variables. Our results clearly illustrate the complexity of the flow in this region and that it is difficult to single out a dominant mechanism that can explain all Loop Current eddy detachments. 相似文献
9.
D. Yu. Vasil’ev N. K. Gavra E. S. Kochetkova Yu. I. Ferapontov 《Russian Meteorology and Hydrology》2013,38(5):351-358
Presented are the results of analyzing the correlation between the total winter and autumn precipitation and the parameters of spring water runoff in the Belaya River basin for the period of 1936–2000. Five regions are defined, and major factors influencing the runoff formation in each of them are listed. The correlation between the runoff characteristics and the total precipitation is estimated; it can be used for developing the methodological instructions for the runoff forecast in different areas of Bashkortostan. 相似文献
10.
季风和ENSO是影响亚洲和中国气候变化的两大系统,随着气候动力学研究的深入,国内外学者对季风及其与ENSO循环相互作用的研究取得了很大进展.作者回顾了近年来国内外关于季风动力学以及季风与ENSO循环相互作用的研究进展,主要综述了中国学者关于亚洲季风的认识与表述的深化,特别是对于季风的特征、系统性和年循环现象的认识.还回顾了中国关于亚洲季风的季内、年际和年代际变化、亚洲季风与ENSO循环相互作用等方面的研究进展.此外,还提出在季风动力学以及季风与ENSO循环相互作用方面需进一步研究的问题. 相似文献
11.
Variations of the summer Somali and Australia cross-equatorial flows and the implications for the Asian summer monsoon 总被引：3，自引：0，他引：3
The temporal variations during 1948-2010 and vertical structures of the summer Somali and Australia cross-equatorial flows(CEFs) and the implications for the Asian summer monsoon were explored in this study.The strongest southerly and northerly CEFs exist at 925 hPa and 150 hPa level,respectively.The low-level Somali(LLS) CEFs were significantly connected with the rainfall in most regions of India(especially the monsoon regions),except in a small area in southwest India.In comparison to the climatology,the lowlevel Australia(LLA) CEFs exhibited stronger variations at interannual time scale and are more closely connected to the East Asian summer monsoon circulation than to the LLS CEFs.The East Asian summer monsoon circulation anomalies related to stronger LLA CEFs were associated with less water vapor content and less rainfall in the region between the middle Yellow River and Yangtze River and with more water vapor and more rainfall in southern China.The sea-surface temperature anomalies east of Australia related to summer LLA CEFs emerge in spring and persist into summer,with implications for the seasonal prediction of summer rainfall in East Asia.The connection between the LLA CEFs and East Asian summer monsoon rainfall may be partly due to its linkage with El Nino-Southern Oscillation.In addition,both the LLA and LLS CEFs exhibited interdecadal shifts in the late 1970s and the late 1990s,consistent with the phase shifts of Pacific Decadal Oscillation(PDO). 相似文献
12.
Isabella M. Angelini Michael Garstang Robert E. Davis Bruce Hayden David R. Fitzjarrald David R. Legates Steven Greco Stephen Macko Vickie Connors 《Theoretical and Applied Climatology》2011,105(1-2):243-261
Recent studies suggest that vegetation can drive large-scale atmospheric circulations and substantially influence the hydrologic cycle. We present observational evidence to quantify the extent of coupling between vegetation and the overlying atmosphere. Within the context of vegetation–atmospheric interactions, we reanalyze existing climatological data from springtime leaf emergence, emissivity, dew point temperatures, and historical records of precipitation and forest coverage. We construct new rainfall transects based on a robust global climatology. Using isotopic analysis of precipitation, we find that rain in Amazonia comes primarily from large-scale weather systems coupling interior regions to the ocean and is not directly driven by local evaporation. We find that changes in vegetative cover and state influence the temperature and moisture content of the surface and atmospheric boundary layer but are not reflected in observable precipitation changes. This analysis reaffirms the view that changes in precipitation over continental reaches are a product of complex processes only partly influenced but not controlled by local water sources or vegetation. 相似文献
13.
Considered is a possibility of using the previously developed method for estimating the evapotranspiration from the river basin based on the observations at the network of water- and soil-evaporation stations and on the data on the land use dynamics for the Northern Dvina and Western Dvina river catchments. It is demonstrated that the method enables to obtain rather realistic and reliable estimates both of evapotranspiration over the basin and of the contribution of different landscapes to its value. The value of evapotranspiration and its interannual variability depend not only on the trends in the fluctuations of evaporation from the water surface and the land surface, but also on the changes in landscape characteristics. The present paper is a continuation of the papers dealing with the study of the basins of the Volga and Don rivers started under V.S. Golubev’s leadership and participation. 相似文献
14.
气候变化对中国农业旱灾损失率的影响及其南北区域差异性 总被引：4，自引：1，他引：3
在全球变暖背景下,干旱灾害对中国农业生产的影响日益严重,然而由于旱灾损失的复杂性及其显著的区域差异,至今对中国农业旱灾损失规律及其影响机制的认识十分有限。文中利用1961年以来中国农业干旱灾害的灾情资料和常规气象资料,系统分析了近50年来中国农业干旱灾害不同受灾强度分布比率和综合损失率等指标的变化趋势及其在北方和南方的区域差异,研究了20世纪90年代的气温突变对农业旱灾损失率的影响特征,探讨了农业旱灾综合损失率对气温和降水等气候要素变化的依赖关系及其在气候空间的分布特征。结果发现,在气候变化背景下,近50年来中国农业旱灾综合损失率平均每10 a约增加0.5%,风险明显增大。而且,北方综合损失率每10 a约增加0.6%,高出南方1倍,风险增大的速度明显比南方快;北方农业旱灾几乎在很宽松的气温条件下就可以发生,而南方更多发生在气温较高的年份。并且,在气温突变后,变化趋势明显加剧,全中国综合损失率约增加了0.9%,风险明显增高;而且北方综合损失率的增值高达1.8%,是南方的4倍还多,气候突变对北方农业旱灾风险的影响明显比南方更凸出。综合损失率在北方对降水变化的响应要更敏感,而在南方对气温变化的响应更敏感。同时,关键影响期降水对综合损失率的影响比全年降水影响更显著;北方的关键影响期作用比南方更凸出。这些新的科学认识对中国农业旱灾防御具有重要意义。 相似文献
15.
全球副热带高压和赤道辐合带演变规律的分析和应用 总被引：4，自引：0，他引：4
根据卫星观测的OLR(射出长波辐射)资料,分析了全球副热带高压和赤道辐合带的演变规律,探讨了长江流域出现特大洪涝年的异常特征及持续性。结果表明,密切关注11月—2月全球副热带高压的异常分布特征和3—6月赤道辐合带南侧低纬洋面积云对流的强弱,是预报长江流域特大洪涝发生的重要着眼点。 相似文献
16.
In the 1960s North Atlantic sea surface temperatures (SST) cooled rapidly. The magnitude of the cooling was largest in the North Atlantic subpolar gyre (SPG), and was coincident with a rapid freshening of the SPG. Here we analyze hindcasts of the 1960s North Atlantic cooling made with the UK Met Office’s decadal prediction system (DePreSys), which is initialised using observations. It is shown that DePreSys captures—with a lead time of several years—the observed cooling and freshening of the North Atlantic SPG. DePreSys also captures changes in SST over the wider North Atlantic and surface climate impacts over the wider region, such as changes in atmospheric circulation in winter and sea ice extent. We show that initialisation of an anomalously weak Atlantic Meridional Overturning Circulation (AMOC), and hence weak northward heat transport, is crucial for DePreSys to predict the magnitude of the observed cooling. Such an anomalously weak AMOC is not captured when ocean observations are not assimilated (i.e. it is not a forced response in this model). The freshening of the SPG is also dominated by ocean salt transport changes in DePreSys; in particular, the simulation of advective freshwater anomalies analogous to the Great Salinity Anomaly were key. Therefore, DePreSys suggests that ocean dynamics played an important role in the cooling of the North Atlantic in the 1960s, and that this event was predictable. 相似文献
17.
本文利用统计模型、线性拟合和相关分析方法,对气温、降水资料的时空分布和相互间的相关性进行了计算,分析了黑龙江省气候特点。结果表明,黑龙江省气温持续显著升高,主要是最低气温和冬季气温显著升高影响;气温、降水在空间上存在正、负相关区域。 相似文献
18.
氢气作为同等外界条件下密度最小的气体被广泛运用于社会经济活动的某些领域,如大气探测,空中拍摄,节日庆典升空彩球等。但是,由于氢气又是易燃易爆气体,违规操作又会造成极大的危险。本文在总结日常灌充、施放氢气球工作中的经验教训的基础上,结合规范要求,从7个方面讨论了氢气球充灌和施放过程中的安全风险及规避措施,希望能对同行的相关工作有所帮助。 相似文献
19.
利用1956~2012年长江和黄河源区内2个水文站点逐月流量数据,分析了近57a两江源区径流的长期变化趋势、突变特征以及周期特征的异同。结果表明:长江源区径流量月变化呈单峰型,峰值在7月;黄河源区则表现为双峰型,峰值分别出现在7月和9月。近57a来,长江源区各季节及年平均径流量均呈现上升趋势,而黄河源区表现为年平均、春季和秋季平均流量呈下降趋势,而夏季和冬季则表现为上升趋势的特征。长江源区1960年和1968年前后的突变点比较可靠,在1998年前后可能也存在一次突变;而对于黄河源区,则在1960年和1968年前后的突变点具有较高的可靠性。长江源区年径流量主要存在9~10a和准22a的变化周期,而黄河源区年径流主要存在4a、7~8a和准16a的变化周期。 相似文献