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1.
利用NECP/NCAR月平均再分析资料,研究1951～2010年夏季青藏高原主体大气热源分布、对东亚地区的环流影响及其与同期中国降水的关系.针对高原加热局地特征明显的特点,采用旋转经验正交函数等方法探讨不同类型的热源分布以及对东亚地区大气环流的影响.结果表明,当加热中心位于高原东南侧时,青藏高原夏季风加强,南亚高压偏南偏东,西太平洋副热带高压西伸加强,而东亚中高纬地区两脊一槽的经向环流分布形势明显,有利于中国长江流域的降水而不利于华南华北的降水发展.当加热中心位于高原中北部与西南地区时,青藏高原夏季风减弱,南亚高压偏西,西太副高明显偏东偏弱,中高纬环流的纬向特征明显,有利于中国地区北方降水而不利于南方地区的降水. 相似文献
2.
为了找出青藏高原与东西部各分区大气热源的变化规律,利用美国国家环境预报中心的月平均温度场、比湿场、风场以及位势高度场的再分析格点资料,采用"倒算法"计算得到高原地区月平均大气热源原始格点资料,对比分析青藏高原全区与东西部各分区大气热源在1948~2011年的年际和年代际变化特征,证实青藏高原大气热源的时空分布具有显著的差异性,研究结果表明:青藏高原全区和东西各分区的大气热源均表现出明显的年际振荡特征。在变化周期方面,青藏高原全区大气热源存在14年的显著周期,高原东部地区大气热源存在16年的显著周期,高原西部地区大气热源存在8年的显著周期。在变化趋势方面,青藏高原西部地区和东部地区1989年前,大气热源变化趋势相同,1989年后,大气热源变化趋势相反。在大气热源各个季节的空间分布方面,青藏高原全区大气热源各个季节热源热汇分布特征不同,春季西部地区出现热源中心,夏季东部地区出现热源中心,秋季东部地区出现热汇中心,冬季出现西部地区热源中心和东部地区热汇中心共存;在变化趋势突变检测方面,青藏高原全区大气热源在1989年存在显著的突变,西部地区大气热源1976年左右存在显著的突变,东部地区大气热源在1990年左右存在显著的突变。 相似文献
3.
《广东海洋大学学报》2019,(6)
【目的】综述前人对青藏高原大气热源的研究成果,探究大气热源与南海夏季风的关系。【方法】归纳高原大气热源研究进展,采用诊断分析方法探究高原热源的时空分布及与南海夏季风的关系。【结果】1)青藏高原夏季(冬季)大气是热(冷)源,冷热源的季节转换发生在3月,热源强度7月达到最大;2)热源中潜热贡献最大;3)不同资料和方法在描述热源时空分布时存在一定不确定性;4)高原夏季大气热源与南海夏季风呈明显负相关。基于大气热源,构造南海-青藏高原夏季海陆热力性质差异指数,该指数显示1980―2016年海陆热力性质差异有年代际减小的趋势。 相似文献
4.
范伶俐 《广东海洋大学学报》2004,24(4):38-46
用Nino 3指数、印度洋单极指数、偶极子指数描述热带太平洋、印度洋海表温度 (SST)的年际异常 ,季节分析表明 :冬季Nino3区与热带印度洋海表温度距平 (SSTA)相互关系表现为单极 ,且 1976年以后两者的相互关系减弱 ,其可能原因 :一是冬季是ENSO(厄尔尼诺 )事件的盛期 ;二是冬季西太平洋暖水区东移 ,造成两洋的垂直纬向环流耦合减弱。夏季两者相互关系表现为偶极 ,1976年以后两者的相互关系加强 ,其可能原因 ,一是夏季是偶极子盛期 ,ENSO事件的发展期 ;二是夏季西太平洋暖水区虽然东移 ,但暖水区位置偏北 ,且东南印度洋的上升支强度增大 ,造成两洋的纬向环流耦合更强烈 相似文献
5.
范伶俐 《广东海洋大学学报》2004,24(4):38-46
用Nino3指数、印度洋单极指数、偶极子指数描述热带太平洋、印度洋海表温度(SST)的年际异常，季节分析表明：冬季Nino3区与热带印度洋海表温度距平(SSTA)相互关系表现为单极，且1976年以后两者的相互关系减弱，其可能原因：一是冬季是ENSO(厄尔尼诺)事件的盛期；二是冬季西太平洋暖水区东移，造成两洋的垂直纬向环流耦合减弱。夏季两者相互关系表现为偶极，1976年以后两者的相互关系加强，其可能原因，一是夏季是偶极子盛期，ENSO事件的发展期；二是夏季西太平洋暖水区虽然东移，但暖水区位置偏北，且东南印度洋的上升支强度增大，造成两洋的．纬向环流耦合更强烈。 相似文献
6.
用1961—2008年NOAA的月平均再分析资料和1980—2006年云南5个探空站的资料,采用大气可降水量和水汽通量公式计算分析大气可降水量和水汽通量,并用线性趋势分析其变化特征。结果表明：云南四季的可降水量北少南多,呈“u”型分布,夏季最大,冬季最小。对云南地区四季的水汽通量分析表明,四季的水汽净收入主要集中在对流层低层;地面-300hPa的水汽净收入在夏季最大、秋季次之,而冬季最小。云南经向的水汽输送和纬向的水汽输送呈反相关,近48年,云南四季水汽呈增加趋势,其中夏季增加最多,春季次之。 相似文献
7.
冬夏季热带太平洋至印度洋次表层海温变化的模态特征 总被引：1，自引：1，他引：0
采用美国Scripps海洋研究所的1955—1998年全球海洋上层海水温度月距平资料,对热带太平洋至印度洋各层海温进行经验正交函数分解,分析其主要模态特征。结果表明：热带太平洋至印度洋次表层海温场主要表现出东、西太平洋海温异常反位相变化的特征,异常强度冬季明显强于夏季。冬季赤道东太平洋40m层,东印度洋至西太平洋120m层,夏季赤道东太平洋40m层,东印度洋至西太平洋160m层为海温异常的显著区域。冬季0—60m层第一特征向量表现出厄尔尼诺（拉尼娜）模态特征,第二特征向量表现出海温异常的东西运移模态特征,80—400m层第一特征向量表现出西太平洋暖池模态特征,第二特征向量表现出海温异常的东西运移模态特征。夏季0—60m层特征向量表现出厄尔尼诺（拉尼娜）模态,80—400m层特征向量表现出西太平洋暖池模态特征。 相似文献
8.
青藏高原冬季降水的气候特征认识对高原冬季雪灾的防御有着重要意义。基于青藏高原54个气象站1971~2010年冬季(12~2月)逐月降水量资料,利用现代统计方法分析了青藏高原冬季降水的时空分布特征及突变现象,利用经验正交函数(EOF)和旋转经验正交函数(REOF)概括出高原冬季降水的6种主要空间分布型以及区域性特征进行分析。结果表明:冬季降水分布不均匀,偏东偏南部降水量相对较多,冬季降水在12月最少,2月最多;EOF对青藏高原地区冬季降水分解为6种模态,全区一致型、南北部型、东西部型、川西型、高原腹地型和西部型模态;EOF第1模态时间系数表明高原大部分地区冬季降水在20世纪90年代有显著增加、且存在14年左右的周期变化特征。REOF分析表明,高原地区冬季降水的局地特征显著,而高原腹地与中东部地区变化特征显示了高原冬季降水的主要变化特征,与EOF分析第1模态的变化特征较为一致。 相似文献
9.
使用2001年和2003年NCEP/NCAR再分析资料计算夏季亚洲季风区大气热源（汇）,再用BUTTER-WORTH带通滤波器对原始热源（汇）场进行带通滤波,得到2001与2003年夏季30-60天的大气热源（汇）的低频分量,然后分析两年夏季东亚各区域大气热源（汇）及其低频变化特征、传播特征和传播差异,得出以下结论：（1）2001年呈连续带状分布;2003年热源中心分布零散且位置显著东移,热源（汇）强度比2001年减弱;（2）2001年和2003年低频分量的平均分布有明显差异,且旱年低频分量强度远大于涝年;（3）2001年低频振荡向北传播范围仅到20°N-30°N的华南至江南地区,而2003年低频振荡多数可达30°N以北的江淮流域;（4）2001年低频分量纬向传播均为自西向东,而2003年在6-8月期间自东向西传播,5月和9月则主要由西向东传播。因此,江淮流域典型旱涝年分2001年和2003年在低频分量的配置和低频波的传播上存在明显差异,这可能正是导致这两年气候巨大差异的原因之一。 相似文献
10.
青藏高原大气热源气候特征的研究 总被引：2，自引：0，他引：2
用NCEP/NCAR再分析资料和小波分析方法分析研究了1950-2005年青藏高原大气热源气候特征和变化特征,主要结论包括:(1)夏季青藏高原东部大气热源的强度明显较西部大.6月份,高原东部热源的强度是高原西部的近两倍,7月份的值也比西部大了40%以上.(2)青藏高原全区、东部和西部逐年平均的大气热源有明显不同的变化特征.高原全区年平均大气热源的变化主要是一个14年的时间尺度;高原东部不仅有14年的主要时间变化尺度,同时还有一个非常显著的2.6年的时间变化尺度;高原西部则不同,是一个不明显的1-2年的时间尺度. 相似文献
11.
《中国海洋大学学报(英文版)》2015,(4)
The seasonal and interannual variability of zonal mean Hadley circulation are analyzed, and the important effects of sea surface temperature(SST), especially the tropical Pacific SST, on the meridional circulation are discussed. Following results are obtained: 1) the Hadley circulation presents a single clockwise(anticlockwise) cross-equator circulation in the Northern(Southern) Hemisphere winter,while it is a double-ring-shaped circulation quasi-symmetric about the equator in spring and autumn. The annual mean state just indicates the residual of the Hadley cell in winter and summer. 2) The first mode of interannual anomalies shows a single cell crossing the equator like the climatology in winter and summer but with narrower width. The second mode shows a double ring-shaped cell quasi-symmetric about the equator which is similar to the Hadley cell in spring or autumn. 3) Vertical motion of the Hadley circulation is driven by sea surface temperature(SST) through latent and sensible heat in the tropics, and the interannual anomalies are mainly driven by the SST anomaly(SSTa) in the tropical Pacific. 4) The meridional gradient of SSTa is well consistent with the lower meridional wind of Hadley circulation in the interannual part. For the spatial distribution, the meridional gradient of SSTa in the Pacific plays a major role for the first two modes while the effects of the Indian Ocean and the Atlantic Ocean can be ignored. 相似文献
12.
The sensitivity of the global atmospheric and oceanic response to sea surface temperature anomaly (SSTA) throughout the South China Sea (SCS) is investigated using the Fast Ocean-Atmosphere Model (FOAM). Forced by a warming SST, the experiment explicitly demonstrates that the responses of surface air temperature (SAT) and SST exhibit positive anomalous center over SCS and negative anomalous center over the Northern Pacific Ocean (NPO). The atmospheric response to the warm SST anomalies is characterized by a barotropical anomaly in middle-latitude, leading to a weak subtropical high in summer and a weak Aleutian low in winter. Accordingly, Indian monsoon and eastern Asian monsoon strengthen in summer but weaken in winter as a result of wind convergence owing to the warm SST. It is worth noting that the abnormal signals propagate poleward and eastward away in the form of Rossby Waves from the forcing region, which induces high pressure anomaly. Owing to action of the wind-driven circulation, an anomalous anti-cyclonic circulation is induced with a primary southward current in the upper ocean. An obvious cooling appears over the North Pacific, which can be explained by anomalous meridional cold advection and mixing as shown in the analysises of heat budget and other factors that affect SST. 相似文献
13.
ENSO cycle and climate anomaly in China 总被引：2，自引：0，他引：2
The inter-annual variability of the tropical Pacific Subsurface Ocean Temperature Anomaly (SOTA) and the associated anomalous atmospheric circulation over the Asian North Pacific during the El Ni o-Southern Oscillation (ENSO) were investigated using National Centers for Environmental Prediction/ National Center for Atmospheric Research (NCEP/NCAR) atmospheric reanalysis data and simple ocean data simulation (SODA). The relationship between the ENSO and the climate of China was revealed. The main results indicated the following: 1) there are two ENSO modes acting on the subsurface tropical Pacific. The first mode is related to the mature phase of ENSO, which mainly appears during winter. The second mode is associated with a transition stage of the ENSO developing or decaying, which mainly occurs during summer; 2) during the mature phase of El Ni o, the meridionality of the atmosphere in the mid-high latitude increases, the Aleutian low and high pressure ridge over Lake Baikal strengthens, northerly winds prevail in northern China, and precipitation in northern China decreases significantly. The ridge of the Ural High strengthens during the decaying phase of El Ni o, as atmospheric circulation is sustained during winter, and the northerly wind anomaly appears in northern China during summer. Due to the ascending branch of the Walker circulation over the western Pacific, the western Pacific Subtropical High becomes weaker, and south-southeasterly winds prevail over southern China. As a result, less rainfall occurs over northern China and more rainfall over the Changjiang River basin and the southwestern and eastern region of Inner Mongolia. The flood disaster that occurred south of Changjiang River can be attributed to this. The La Ni a event causes an opposite, but weaker effect; 3) the ENSO cycle can influence climate anomalies within China via zonal and meridional heat transport. This is known as the "atmospheric-bridge", where the energy anomaly within the tropical Pacific transfers to the mid-high latitude in the northern Pacific through Hadley cells and Rossby waves, and to the western Pacific-eastern Indian Ocean through Walker circulation. This research also discusses the special air-sea boundary processes during the ENSO events in the tropical Pacific, and indicates that the influence of the subsurface water of the tropical Pacific on the atmospheric circulation may be realized through the sea surface temperature anomalies of the mixed water, which contact the atmosphere and transfer the anomalous heat and moisture to the atmosphere directly. Moreover, the reason for the heavy flood within the Changjiang River during the summer of 1998 is reviewed in this paper. 相似文献
14.
mODUCnONTheSOuthChinaSea(SCS)isasend-enclosedoceanbasinlocatednearthewesternPeripheryofthePacificOcean.SpreadingfIDmtheeqUatorto20"Nands~ngzonallaboutl5'inlooptUde,theSCSlocatesbetweenthesouthChinacoastandtheInaritha6continent,andissurroundedbyInanislandcountries.Duringwinter,S0UthwwhmedngcoldSUrges,mwhfiedbytheSST,affectthepressure,tempethe,andwindfieldsneartheInaritimecontinent,andsomeInayeveninIluencetheS0uthernHdrispheremonsoon(Davids0netal.,1983).msuniqUegeOpophyoftheSCS… 相似文献
15.
During the Global Weather Experiment oceanographic measurements were recorded during winter and summer in the western Pacific
region 5°S−5°N, 160°E−175°E. The variations of the upper ocean temperature and salinity fields were produced by the large
seasonal and spatial wind fluctuations. The vertical temperature structure of the thermocline at the equator, the meridional
slope of the thermocline south of the equator, and the northward penetration of high salinity water were related to the direction
and intensity of the zonal wind-stress.
(NOAA Pacific Marine Environmental Laboratory)
Contribution No. 1307 from the Institute of Ocean., Academia Sinica. Received Sept. 3, 1985 相似文献
16.
《山地科学学报》2021,(10)
There are numerous studies on polar amplification and its influence on mid-latitude weather and climate. However, assessments on whether polar amplification occurs in Antarctica are rarely conducted. Based on the latest atmospheric reanalysis of ERA5 produced by European Centre for Medium-Range Weather Forecasts(ECMWF), we have defined the Antarctic amplification index, and calculated the trend of annual and seasonal Surface Air Temperature(SAT) mean during 1979-2019 for Antarctic Ice Sheet(AIS) and the trend mean of different meridional sectors of Antarctic sub regions including East Antarctic Ice Sheet(EAIS), West Antarctic Ice Sheet(WAIS) and Antarctic Peninsula(AP). Antarctic amplification shows regional differences and seasonal variations. Antarctica shows a slight warming with the largest magnitude in AP. The temperature anomalies indicate the least fluctuations in austral summer, and the more fluctuations in winter and spring. In austral summer, the warming trend domains EAIS and WAIS, while the cooling trend appears over AP. The zonal mean in Southern Hemisphere maintains a warming trend in the low latitudes, and fluctuates greatly in the middle and high latitudes. The strongest Antarctic amplification phenomenon occurs in spring, with the amplification index of 1.20. For AP, the amplification occurs in austral autumn, and the amplification index is 2.16. At South Pole and the surrounding regions, SAT for land only fluctuates largely and shows different trends in different seasons. The mechanism of Antarctic amplification is unclear till now, and its research suffers from the limitation of measured data. This suggests that future research needs progress in comprehensive ground observation network, remote sensing data accumulation, and high-resolution climate modeling with better representation of both atmospheric and cryospheric processes in Antarctica. 相似文献
17.
Guofeng Zhu Dahe Qin Huali Tong Yuanfeng Liu Jiafang Li Dongdong Chen Kai Wang Pengfei Hu 《中国地理科学(英文版)》2016,26(5):687-702
The Thornthwaite moisture index, an index of the supply of water(precipitation) in an area relative to the climatic demand for water(potential evapotranspiration), was used to examine the spatial and temporal variation of drought and to verify the influence of environmental factors on the drought in the Hengduan Mountains, China. Results indicate that the Thornthwaite moisture index in the Hengduan Mountains had been increasing since 1960 with a rate of 0.1938/yr. Annual Thornthwaite moisture index in Hengduan Mountains was between –97.47 and 67.43 and the spatial heterogeneity was obvious in different seasons. Thornthwaite moisture index was high in the north and low in the south, and the monsoon rainfall had a significant impact on its spatial distribution. The tendency rate of Thornthwaite moisture index variation varied in different seasons, and the increasing trends in spring were greater than that in summer and autumn. However, the Thornthwaite moisture index decreased in winter. Thornthwaite moisture index increased greatly in the north and there was a small growth in the south of Hengduan Mountains. The increase of precipitation and decrease of evaporation lead to the increase of Thornthwaite moisture index. Thornthwaite moisture index has strong correlation with vegetation coverage. It can be seen that the correlation between Normalized Difference Vegetation Index(NDVI) and Thornthwaite moisture index was positive in spring and summer, but negative in autumn and winter. Correlation between Thornthwaite moisture index and relative soil relative moisture content was positive in spring, summer and autumn, but negative in winter. The typical mountainous terrain affect the distribution of temperature, precipitation, wind speed and other meteorological factors in this region, and then affect the spatial distribution of Thornthwaite moisture index. The unique ridge-gorge terrain caused the continuity of water-heat distribution from the north to south, and the water-heat was stronger than that from the east to west part, and thus determined the spatial distribution of Thornthwaite moisture index. The drought in the Hengduan Mountains area is mainly due to the unstable South Asian monsoon rainfall time. 相似文献
18.
We analyzed the temporal and spatial variation, and interannual variability of the North Pacific meridional overturning circulation using an empirical orthogonal function method, and calculated mass transport using Simple Ocean Data Assimilation Data from 1958–2008. The meridional streamfunction field in the North Pacific tilts N-S; the Tropical Cell (TC), Subtropical Cell (STC), and Deep Tropical Cell (DTC) may be in phase on an annual time scale; the TC and the STC are out of phase on an interannual time scale, but the interannual variability of the DTC is complex. The TC and STC interannual variability is associated with ENSO (El Niño-Southern Oscillation). The TC northward, southward, upward, and downward transports all weaken in El Niños and strengthen in La Niñas. The STC northward and southward transports are out of phase, while the STC northward and downward transports are in phase. Sea-surface water that reaches the middle latitude and is subducted may not completely return to the tropics. The zonal wind anomalies over the central North Pacific, which control Ekman transport, and the east-west slope of the sea level may be major factors causing the TC northward and southward transport interannual variability and the STC northward and southward transports on the interannual time scale. The DTC northward and southward transports decrease during strong El Niños and increase during strong La Niñas. DTC upward and downward transports are not strongly correlated with the Niño-3 index and may not be completely controlled by ENSO. 相似文献
19.
本文对近30 a以来中国上空臭氧总量的时空动态变化特征进行遥感监测与分析。结果表明,中国上空的臭氧总量在持续下降,下降速度低于全球臭氧总量下降速度,而与北半球下降速度基本一致,略低于北半球下降速度。中国臭氧总量每年平均减少0.11%,大约下降0.36 DU,但2000年后中国臭氧总量下降的速度有所减缓,尤其是2005年以来,中国臭氧总量呈上升趋势,这与全球的臭氧总量变化趋势相同。中国臭氧总量的季节变化呈正弦曲线变化,最大和最小值分别出现在3月和10月,平均值大约分别为333.36 DU和284.54 DU。中国臭氧总量季节变化在纬度方向上不明显,而在经度方向上变化较大,同纬度地区臭氧总量,东部地区的大于西部地区的,南北方地区臭氧总量季节变化几乎呈相反的趋势。 相似文献
20.
《中国海洋湖沼学报》2021,(4)
Impact factors on the salinity budget,especially the eddy salt fluxes and smaller-scale diffusive salt fluxes for the upper 50 m of the Bay of Bengal(BoB) in 2014 are investigated using a box model based on the Regional Ocean Modeling System(ROMS) daily outputs.The model results reproduce that the precipitation and river runoffs are the dominant factors modulating the sharp salinity decrease during the summer monsoon season.The analysis shows that the salinity increase after the summer monsoon is mostly due to the meridional advective and diffusive salt fluxes.The vertical advective salt flux,which is sensitive to the different signals of the wind stress curl,plays an important role in balancing the salinity change induced by the meridional advective salt flux during both the summer and winter monsoon seasons.Distinctive spatial mesosc ale structures are presented in the eddy salt flux throughout the year,and their contributions are sizeable(over 30% in the meridional direction and about 10%-30% in the vertical direction).The meridional eddy salt flux is larger in the monsoon seasons than that in the inter-monsoon seasons,and in a positive pattern near the western boundary during the winter monsoon and autumn inter-monsoon.The vertical eddy salt flux makes an important contribution to the salinity budget,especially along the coastal area and around the Andaman and Nicobar Islands.The vertical eddy salt flux becomes large when a tropical cyclone passes the area. 相似文献