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1.
In the present study, it was found that there was a significant climate regime shift in 1993 from average rainfall amounts in winter (December of a year and January and February of the next year) in North Korea over the last 30 years (1982–2011). This significant climate regime shift in 1993 also appeared in empirical orthogonal function analysis conducted using the winter mean rainfall amounts observed at 26 weather observation stations in North Korea. The reason why winter mean rainfall amounts in North Korea were smaller during the period of 1994–2011 than during the period of 1982–1994 was that anomalous anticyclone was reinforced in regions near Lake Baikal while anomalous cyclone was reinforced on the sea on the east of Japan so that the winter pressure system pattern (west high-east low pattern) appeared and thus anomalous cold and dry northerlies were reinforced in most East Asian regions including North Korea. To figure out the reason why anomalous anticyclone was reinforced further in the East Asian continent in winters during the period of 1994–2011, differences in water equivalent of accumulated snow depths between the two periods were analyzed. As a result, more snow was observed in most East Asian regions during the period of 1994–2011. Therefore, anomalous anticyclone could be further reinforced in the East Asian continent because surface air temperature dropped further due to snow-albedo effect. The surface air temperature cooling deepened further in the East Asian continent during the period of 1994–2011 due to snow-albedo effect was identified through differences in sensible heat net flux between the two periods. 相似文献
2.
The present study revealed that a climate regime shift occurred during the 1988–1991 period involving changes in tropical cyclone (TC) intensity (central pressure, maximum sustained wind speed) during the summer near 30°N in East Asia. Climatologically, TC intensity at 110°–125°E near 30°N (over Mainland China) is the weakest at that latitude while the strongest is found at 125°–130°E (over Korea). The TC intensity during the 1991–2015 (91–15) period had strengthened significantly compared to that of the 1965–1988 (65–88) period. The strengthening was due to a significantly lower frequency of TCs that passed through Mainland China during the 91–15 period. This lower frequency of was due to anomalous northeasterlies blown from the anomalous anticyclonic circulation located over continental East Asia and that had strengthened along the coast. Instead, TCs mainly followed a path from eastern regions in the subtropical western North Pacific to Korea and Japan via the East China Sea due to anomalous cyclonic circulations that had strengthened in the western North Pacific. In addition, low vertical wind shear had formed along the mid-latitude region in East Asia and along the main TC track in the 91–15 period, and most regions in the western North Pacific experienced a higher sea surface temperature state during the 91–15 period than in the previous period, indicating that a favorable environment had formed to maintain strong intensities of TCs at the mid–latitudes. The characteristics of TCs at the lower latitudes caused a strong TC intensity at the time of landfall in Korea and a gradual shifting trend of landing location from the western to southern coast in recent years. 相似文献
3.
利用1979～2013年NCEP/NCAR月平均再分析资料及NOAA研究中心的CMAP（CPC Merged Analysis of Precipitation）月平均降水资料,通过定义欧亚—北太平洋间大气质量迁移指数IMAMEP,分析了春季欧亚—北太平洋上空大气质量迁移（MAMEP,Migration of Atmospheric Mass over Regions between Eurasia and North Pacific）的年际变化规律及其与同期中国气候异常的联系。结果表明:在北半球中高纬度存在一个纬向分布的欧亚—北太平洋遥相关型,且其可能对中国同期气候异常的形成具有重要影响。春季MAMEP指数具有显著的长期趋势,同时还具有2～4年及5～7年的振荡周期及明显的年代际变化特征。垂直环流和波动运动对欧亚—北太平洋间大气质量迁移具有重要作用。大气质量在欧亚西部低层异常辐合,高层异常辐散,在中、西太平洋地区低层异常辐散,高层异常辐合,在纬向上构成了顺时针的垂直环流圈,将西北太平洋地区的大气质量变动与欧亚大陆上空的变动联系了起来。另外,来自西欧大陆的波扰能量可传播至北太平洋,有利于这些区域上空位势高度异常扰动的维持。IMAMEP与春季同期降水及地表气温异常关系密切。IMAMEP为正时,东亚以北地区、鄂霍次克海西岸以及西欧沿岸降水显著减少,欧亚西部及我国华北地区降水显著增加。850 hPa上西伯利亚受反气旋式环流控制,太平洋上空受气旋式环流控制,引起欧亚大陆北部地表显著增温,西伯利亚以东、我国东北、华北—江淮地区及韩国、日本南部地表显著降温。西欧—我国西北部分地区大面积显著降温现象与这两个地区受异常反气旋东侧的偏北气流影响有关。这些结果有利于人们更深刻认识区域春季气候异常形成机理。 相似文献
4.
冬半年欧亚雪盖变化对东亚环流的影响 总被引：7，自引：1，他引：6
对１９７３～１９９４年期间欧亚雪盖和东亚５００ｈＰａ高度距平资料进行旋转扩展主成分分析,研究了冬半年欧亚雪盖异常与后期夏半年东亚环流分布连续演变的关系及其可能机制。结果表明前期秋冬春季欧洲、中亚和东亚中高纬雪盖异常不同的动态变化激发出具有不同持续性的东亚低频流型,而夏半年东亚副热带环流纬向扩展型演变与前期冬半年欧亚雪盖异常无关。 相似文献
5.
The statistical change-point analysis demonstrates that there is a climate regime shift in the April mean precipitation in Korea in 1981. The April mean precipitation in the years post-1981 showed a distinct decrease compared to the years pre-1981. This phenomenon was also noticed in China and Japan, excluding south China. One of the major causes for this decrease in April mean precipitation was the increased snow depth in the mid-latitude regions of continental East Asia. This resulted in a strengthened cold and dry anticyclone anomaly over continental East Asia and a relatively weakened subtropical anticyclone anomaly over the western North Pacific, thus forcing a continuation of the typical winter pressure pattern of “high-West and low-East” in East Asia in April. The strengthened northerly anomaly from this zonal pressure pattern anomaly played a significant role in restricting the northern movement of the subtropical anticyclone and preventing the inflow of warm and humid air into Korea.
相似文献6.
欧亚大陆积雪是重要的气候预测因子,评估其在气候模式中的预测潜力可为季节气候预测和模式发展提供重要参考。本文利用IAP AGCM4的多年集合后报结果,分析了欧亚大陆春季雪水当量的可预报性。结果表明该模式对提前1月后报的欧亚大陆春季雪水当量的空间分布,主要模态及变化趋势具有较好的可预报能力。此外模式对欧亚中高纬积雪的年际异常也具有较高的预报技巧,特别是高纬度区域。可预报性来源分析则表明,大气初始异常对欧亚中高纬积雪可预报性的影响与海温异常相比显得更为重要。 相似文献
7.
欧亚大陆积雪对我国春季气候可预报性的影响 总被引：1，自引：0，他引：1
利用大气环流模式IAP9L_CoLM,通过两组集合后报试验,考察了欧亚大陆积雪对我国春季气候可预报性的影响。一组试验为常规后报试验,积雪是由模式陆面过程预报得到的,另一组试验为积雪试验,模式积分过程中欧亚大陆雪水当量由微波遥感积雪资料替代,一天替换一次。通过分析两组试验后报结果的差异,来考察欧亚大陆积雪对我国春季（3~5月）气候可预报性的影响。分析表明:欧亚大陆积雪模拟水平的改善能提高春季欧亚大陆中高纬环流场（海平面气压场和中、高层位势高度场）的可预报性,模式对我国春季气温异常的年际变化和空间分布的可预报能力也有显著增强。对我国春季降水,虽然预报技巧较低,但引入较真实的欧亚积雪作用后,由于中高纬环流场预报技巧的改进导致降水的预测能力也有所改进。个例分析也表明,欧亚中高纬春季积雪异常模拟水平的改善导致了欧亚中高纬贝加尔湖及以南区域环流场可预报性的提高,最终使中国东部区域春季气候异常模拟技巧得以改善。以上结果也证实,欧亚大陆积雪是影响东亚区域春季气候的一个重要因子,要提高模式对中国春季气候的预报技巧,积雪模拟水平的改进是非常必要的。 相似文献
8.
Stratospheric precursor of non-uniform variation in early spring surface temperature over Eurasia 
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下载免费PDF全文 The stratospheric influences on the non-uniform variation in early spring (March–April, MA) surface temperature over Eurasia is investigated based on the ERA-Interim, NCEP-1, and NCEP-2 reanalysis data for the period 1980–2016. A lead–lag correlation is found between preceding winter (December–February, DJF) stratospheric polar vortex displacements (SPVD) and the MA west–east seesaw pattern in surface temperature over Eurasia. Further analysis reveals that the East Asian jet stream may act as a bridge linking DJF SPVD and MA surface temperature over Eurasia. A positive change in SPVD is associated with a decelerated polar jet stream and an accelerated East Asian jet stream in the troposphere in DJF. The East Asian jet stream signal can persist into MA. As a result, anomalous southerly/northerly winds prevail over western/eastern Eurasia, accounting for the west–east surface temperature seesaw over Eurasia. 相似文献
9.
欧亚大陆春季融雪量与东亚夏季风的可能联系 总被引：4，自引：3，他引：1
通过对观测资料的分析, 本文研究了春季欧亚大陆融雪量与东亚夏季风的关系, 并初步讨论了其可能联系机制。研究表明, 春季融雪量EOF (Empirical Orthogonal Function) 第一模态表现出年代际变化特征, 这与东亚夏季风和中国夏季降水的年代际转型具有非常好的一致性。而EOF第二模态与东亚夏季风在年际尺度上具有同位相变化关系, 当春季融雪量在东西伯利亚和巴尔喀什湖附近异常偏多时, 后期在东亚地区容易出现由高纬至低纬的“负—正—负”经向波列结构。融雪量异常偏少时, 情况则相反。文中初步分析了春季融雪量异常与后期夏季东亚地区大气环流出现经向波列结构的可能联系机制, 指出东西伯利亚以及巴尔喀什湖附近异常偏多的春季融雪量能够在该地区促使位势高度场表现为正异常, 随着时间的演变, 巴尔喀什湖附近地区的高压向东移动发展, 东西伯利亚地区的高压一部分向低纬移动, 可能造成夏季东亚地区的经向波列结构, 进而对东亚的天气和气候产生影响。 相似文献
10.
The present study discovered a strong negative correlation between Korea-landfalling tropical cyclone (TC) frequency and Pacific Decadal Oscillation (PDO) in the summer. Thus, the present study selected years that had the highest PDO index (positive PDO years) and years that had the lowest PDO index (negative PDO years) to analyze a mean difference between the two phases in order to determine the reason for the strong negative correlation between the two variables. In the positive PDO years, TCs were mainly generated in the southeastern part of the western North Pacific, and lower TC passage frequency was found in most regions in the mid-latitude in East Asia. Moreover, a slightly weaker TC intensity than that in the negative PDO years was revealed. In order to determine the cause of the TC activity revealed in the positive PDO years, 850 hPa and 500 hPa stream flows were analyzed first. In the mid-latitude region in East Asia, anomalous huge cyclonic circulations were strengthened, while anomalous anticyclonic circulations were strengthened in the low-latitude region. Accordingly, Korea was being influenced by anomalous northwesterlies, which played a role in blocking TCs from moving northward to Korea. The results of analysis on 850 hPa air temperature, precipitation, 600 hPa relative humidity, and sea surface temperature (SST) showed that negative anomalies were strengthened in the northwest region in the western North Pacific while positive anomalies were strengthened in the southeast region. The atmospheric and oceanic environments were related to frequent occurrences of TCs in the southeast region in the western North Pacific during the positive PDO years. All factors of air temperature, precipitation, 600 hPa relative humidity, and SST revealed negative (positive for vertical wind shear) anomalies near Korea, so that atmospheric and oceanic environments were formed that could rapidly weaken TC intensity, even if the TCs moved northward to Korea in the positive PDO years. 相似文献
11.
春季欧亚大陆积雪对春夏季南北半球大气质量交换的可能影响 总被引：2，自引：0，他引：2
本文基于春季欧亚雪盖资料与大气再分析资料的奇异值分解(SVD)分析结果,结合数值试验,研究了春季欧亚大陆积雪变化与春、夏季南北半球大气质量交换的联系。研究表明,当春季欧亚积雪异常偏多时,同期欧亚大陆中高纬大范围地区的地面气温异常偏低,这种冷却效应可能持续至夏季,同时,冷空气的堆积造成了欧亚大陆地表气压(气柱大气质量)的增加,并且对应了夏季北半球大气总质量的异常上升,而南半球大气质量却明显下降。分析发现,春季欧亚积雪异常与夏季南北半球际大气质量涛动存在显著的滞后相关,而且前者还与同期及后期包括索马里急流和对流层上部80°E~120°E区域高空急流在内的多处越赤道气流变化联系密切。从数值模拟结果分析发现,以改变春季初始积雪状况作为驱动,欧亚大陆中高纬地区的低层大气环流出现了显著响应,即当积雪增加时,同期及其后夏季地面气温显著降低,并且冷异常区域对应着气柱质量的异常升高。 相似文献
12.
欧亚北部冬季增雪“影响”我国夏季气候异常的机理研究——陆面季节演变异常的“纽带”作用 总被引：10，自引：6，他引：4
本文主要利用美国冰雪资料中心 (The National Snow and Ice Data Center) 提供的卫星反演积雪资料和ERA40土壤温度再分析资料, 采用相关分析, 对欧亚北部冬季新增雪盖面积 (冬季TFSE) 与我国夏季气候异常关系的可能物理途径进行了初步研究。结果表明, 春夏季陆面季节演变异常是上述“隔季相关” 的重要纽带: 当冬季TFSE偏大时, 欧亚北部大范围积雪—冻土自西向东、 由南向北的融化进程明显减慢, 受其影响, 至夏季, 东亚中高纬区积雪和地表冻土的融化异常强烈, 土壤温度明显偏低, 这种夏季陆面异常可能通过自身的冷却作用, 通过加强东亚中高纬异常北风对东亚中纬区夏季变冷产生直接影响, 进而与西太平洋副热带高压, 乃至与我国江南夏季降水异常产生关联; 冬季TFSE偏小时相反。分析表明, 冬季TFSE信号在东亚中高纬局地的春季积雪—冻土融化过程中被加强, 并在夏季达到显著。 相似文献
13.
Possible impacts of Barents Sea ice on the Eurasian atmospheric circulation and the rainfall of East China in the beginning of summer 总被引：2，自引：1，他引：1
Possible influences of the Barents Sea ice anomalies on the Eurasian atmospheric circulation and the East China precipitation distribution in the late spring and early summer (May-June) are investigated by analyzing the observational data and the output of an atmospheric general circulation model (AGCM).The study indicates that the sea ice condition of the Barents Sea from May to July may be interrelated with the atmospheric circulation of June. When there is more than average sea ice in the Barents Sea, the local geopotential height of the 500-hPa level will decrease, and the same height in the Lake Baikal and Okhotsk regions will increase and decrease respectively to form a wave-chain structure over North Eurasia.This kind of anomalous height pattern is beneficial to more precipitation in the south part of East China and less in the north. 相似文献
14.
利用1979—2009年JRA-25和NCEP/NCAR再分析资料,通过复矢量经验正交方法揭示了东亚地区夏季850 hPa风场变率的优势模态。结果表明:两套再分析资料所揭示的东亚夏季风在20世纪90年代初均发生了年代际转型,与我国夏季降水的年代际转型时间一致。伴随着东亚夏季风的年代际转型,我国北方大部分地区夏季降水减少,尤其是我国东北北部和长江、黄河之间105°E附近区域显著减少,而华南地区和淮河流域降水显著增加。从动力上解释我国夏季降水年代际转型特征,夏季500 hPa高度场两个时段 (1993—2009年和1979—1992年) 的差值分布显示为欧亚大陆北部准纬向遥相关波列,夏季850 hPa风场差值分布表现为贝加尔湖东南侧和日本以南地区存在两个异常反气旋式环流,而我国南方地区和鄂霍次克海附近均为异常气旋式环流。夏季西北太平洋、北印度洋以及部分中高纬度海洋的海温和春季欧亚大陆积雪在20世纪90年代初出现显著变化,春季北极海冰的年代际转型发生在20世纪90年代初,都可能成为东亚夏季风年代际转型的原因。 相似文献
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中国春季降水异常及其与热带太平洋海面温度和欧亚大陆积雪的联系 总被引：11，自引：4，他引：7
利用降水观测资料, 研究了1979～2004年中国春季 (3～5月) 标准化累积降水异常的时空特征及其与前冬、 春热带太平洋海面温度和春季欧亚大陆积雪的关系。中国春季标准化累积降水量EOF第一模态最大变率位于中国东部中纬度地区, 主要反映了中国东部中纬度地区春季降水的变化特征。同时, 中国东部春季降水异常具有南、 北反相变化的特征。当长江以南大部分地区的降水偏少时, 长江以北地区的降水偏多。春季降水异常具有显著的年际变化, 但在1980年代末出现年代际转型, 即年际变化的振幅明显增大变强、 周期变长。从华北到长江流域中纬度地区的春季降水异常特征与前冬热带太平洋海面温度有密切的关系。当前冬、 春热带东太平洋海温偏暖, 西太平洋海温偏冷时, 中国东部从华北到长江流域中纬度地区的春季降水偏多, 反之亦然。虽然当春季欧亚大陆楚科奇半岛和青藏高原积雪偏多, 贝加尔湖到中国东北地区的积雪偏少时, 对应着中国东部从华北到长江流域中纬度地区的降水偏多, 但当去掉ENSO信号后, 这种关系并不显著。说明EOF第一模态所反映的中国东部从华北到长江流域中纬度地区春季降水与欧亚大陆积雪的相关关系可能是前冬热带太平洋海面温度异常的一个体现。 相似文献
16.
Interdecadal change in the Eurasia–Pacific anti-phase relation of atmospheric mass and its possible link with PDO 下载免费PDF全文
下载免费PDF全文 Based on the known climatic shift that occurred in 1976, we divide the present study period into two epochs: epoch-I, for 1958–1976; and epoch-II, for 1977–2002. Using ERA-40 and the 20th century reanalysis data, we investigate the interdecadal change in the Eurasia–Pacific anti-phase relation (EPAR) pattern of atmospheric mass (AM) during boreal winter before and after 1976. It is found that anomalous AM over lands is highly and negatively correlated with anomalous AM over oceans in the Northern Hemisphere during the winter season. This correlation does not change much from epoch-I to epoch-II. However, the correlation pattern of surface air pressure anomalies with variations of anomalous AM over lands changes remarkably from epoch-I to epoch-II; the EPAR pattern emerges evidently in the later period, whereas it is not significant in epoch-I. The occurrence of the EPAR pattern in epoch-II may be attributable to the Pacific Decadal Oscillation (PDO). The PDO may modulate the EPAR pattern in two ways. Firstly, the interdecadal component of the PDO as a background may modulate the intensities of the Aleutian low, East Asian trough, and westerly flow, acting as a waveguide during the warm phase (epoch-II) of the PDO. Secondly, the interannual variations of sea surface temperature anomalies in the North Pacific, in association with the PDO, may affect the interannual variations of AM, which facilitates the existence of the EPAR pattern in epoch-II only. With the teleconnection pattern having changed before and after 1976, winter climate anomalies, including rainfall and temperature, are found to be different in many regions in the Northern Hemisphere between epoch-I and epoch-II. All the results of the present work are meaningful for a better understanding of climate anomalies during boreal winter. 相似文献
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18.
Ki-Seon Choi Ja-Yeon Moon Do-Woo Kim Pao-Shin Chu 《Theoretical and Applied Climatology》2010,100(1-2):191-206
This study has developed a multiple linear regression model for the seasonal prediction of the summer tropical cyclone genesis frequency (TCGF) in the western North Pacific using the three teleconnection patterns. These patterns are representative of the Siberian High Oscillation (SHO) in the East Asian continent, the North Pacific Oscillation in the North Pacific, and Antarctic Oscillation (AAO) near the Australia during the boreal spring (April–May). This statistical model is verified through the two analyses: (a) statistical method of cross validation and (b) differences between the high TCGF years and low TCGF years that is hindcasted by the statistical model. The high TCGF years are characterized by the following anomalous features: Three anomalous teleconnection patterns such as anticyclonic circulation (positive SHO phase) in the East Asian continent, pressure pattern like “north-high and south-low” in the North Pacific, and cyclonic circulation (negative AAO phase) near the Australia were strengthened during the period from boreal spring to boreal summer. Thus, anomalous trade winds in the tropical western Pacific (TWP) were weakened by anomalous cyclonic circulations that located in the subtropical western Pacific (SWP) in both hemispheres. In consequence, this spatial distribution of anomalous pressure pattern suppressed convection in the TWP but strengthened convection in the SWP. 相似文献
19.
利用1979—2015年ERA-Interim再分析土壤湿度、云量资料,NCEP/NCAR再分析环流资料和CPC土壤湿度资料,分析了东亚中纬度夏季陆面热力异常的时空分布特征及其与前期春季土壤湿度异常的联系,探讨了前期春季土壤湿度影响东亚中纬度夏季陆面增暖的可能途径。结果表明,东亚中纬度夏季土壤表层温度呈全区一致增暖趋势,其中贝加尔湖及以南地区温度变化最剧烈、增暖最迅速,且1990年代中期前后存在一个明显由冷向暖的年代际转变。进一步分析发现,春、夏季西西伯利亚到贝加尔湖北部地区的土壤湿度与夏季贝加尔湖及以南地区的土壤表层温度在年代际和年际尺度上均存在紧密联系:西西伯利亚到贝加尔湖北部地区土壤湿度异常偏高,通常对应贝加尔湖及南部地区夏季土壤表层温度偏高。西西伯利亚到贝加尔湖北部地区春、夏土壤湿度异常可以引起夏季大气环流异常,从而对东亚夏季中纬度陆面热力异常产生影响:春、夏土壤湿度偏高时,贝加尔湖及其南部地区上空位势高度为正异常,对应为反气旋性异常环流,云量减少,有利于东亚中纬度陆面增暖;反之,则对应为气旋性异常环流,不利于陆面增暖。 相似文献
20.
Using idealized snow forcing to test teleconnections with the Indian summer monsoon in the Hadley Centre GCM 总被引：2，自引：1，他引：1
Anomalous heavy snow during winter or spring has long been regarded as a possible precursor of deficient Indian monsoon rainfall during the subsequent summer. However previous work in this field is inconclusive, in terms of the mechanism that communicates snow anomalies to the monsoon summer, and even the region from which snow has the most impact. In this study we explore these issues in coupled and atmosphere-only versions of the Hadley Centre model. A 1050-year control integration of the HadCM3 coupled model, which well represents the seasonal cycle of snow cover over the Eurasian continent, is analysed and shows evidence for weakened monsoons being preceded by strong snow forcing (in the absence of ENSO) over either the Himalaya/Tibetan Plateau or north/west Eurasia regions. However, empirical orthogonal function (EOF) analysis of springtime interannual variability in snow depth shows the leading mode to have opposite signs between these two regions, suggesting that competing mechanisms may be possible. To determine the dominant region, ensemble integrations are carried out using HadAM3, the atmospheric component of HadCM3, and a variety of anomalous snow forcing initial conditions obtained from the control integration of the coupled model. Forcings are applied during spring in separate experiments over the Himalaya/Tibetan Plateau and north/west Eurasia regions, in conjunction with climatological SSTs in order to avoid the direct effects of ENSO. With the aid of idealized forcing conditions in sensitivity tests, we demonstrate that forcing from the Himalaya region is dominant in this model via a Blanford-type mechanism involving reduced surface sensible heat and longwave fluxes, reduced heating of the troposphere over the Tibetan Plateau and consequently a reduced meridional tropospheric temperature gradient which weakens the monsoon during early summer. Snow albedo is shown to be key to the mechanism, explaining around 50% of the perturbation in sensible heating over the Tibetan Plateau, and accounting for the majority of cooling through the troposphere. 相似文献