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1.
应用美国联合预警中心(Joint Typhoon Warning Center,JTWC)的台风最佳路径资料、美国国家海洋大气局(National Oceanic and Atmospheric Administration,NOAA)的扩展海表面温度资料以及美国国家环境预报中心(National Centers for Environmental Prediction,NCEP)和美国国家大气科学研究中心(National Center for Atmospheric Research,NCAR)的大气环流场资料,研究了20世纪90年代西太平洋暖池(简称暖池)年代际扩张对西北太平洋台风和登陆中国沿岸台风的影响。研究发现,相比于暖池扩张前期(1965—1992),后期(1993—2013)台风生成在西北太平洋中部区域(10°—20°N,135°—145°E)显著减弱,在10°—20°N,145°—160°E区域和南海北部区域则表现出增多的特点。台风移动路径变异特征呈现为移动进入南海和登陆中国东部沿岸的西行和西北行路径减少,登陆日本的转向型路径增多,同时登陆我国海南岛和东南部沿岸的台风增多。进一步探查这种影响的可能原因发现,与暖池扩张密切相关的太平洋年代际变化引起的纬向环流的变异是西北太平洋中部台风生成减少的主要原因;而南海北部台风生成增多则归因于南海区域局地环流特征的变异。同时,南海北部台风生成增多是登陆我国海南岛和东南沿岸台风增多的主要决定因素。 相似文献
2.
海面水温与台风关系的分形分析 总被引：1，自引：0，他引：1
本文用分形方法分析了西北太平洋５３个坐标点１９４９－１９７５年多年逐月平均海面水温资料，结果表明西北太平洋逐月平均海面水温呈分形分布，而且其分维数Ｄ与台风总数有关，即Ｄ值高的月份台风总数也多。 相似文献
3.
用在南海产生、发展的台风的风场资料和海浪资料,总结出处于不同发展阶段的南海台风影响下海面波浪的分布特征和预报关系式。在比较了南海台风与西北太平洋台风形成的波浪分布的差别后,探讨了造成这些差别的原因。最后,对所得的预报关系式作了验证,预报值与观测值比较符合。 相似文献
4.
通过大洋赤道海域SST场差异及其原因分析,提出赤道大西洋、西印度洋及东太平洋表层水温低的可能原因。较详细地讨论了西太平洋暖池形成原因,这是由于西太暖池决定了Walker环流的产生,而Walker环流的移动和演变同样会对暖池区变化产生重要影响。 相似文献
5.
分析了西北太平洋海域1993—2015年发生的超强台风过程的时空分布特征,发现超强台风高发区主要分布在菲律宾以东(124°~140°E,14°~20°N)海域。近20a来西北太平洋超强台风发生频率呈增加趋势。利用两层约化重力模型计算了西北太平洋海域26℃等温线深度(H26),通过ARGO资料评估验证了该方法的可靠性。基于超强台风最大风速分类,进一步讨论了超强台风最终发展强度和其过境前上层海洋热力结构的关系,发现超强台风过境前海洋H26越深、海面温度(SST)越偏暖,上层海洋有效热含量(UOHCv)值就越大且UOHCv正异常越大,越有利于台风短时间内发展增强到超强台风。分析显示,超强台风最终达到的强度和超强台风单位时间掠过海面的UOHCv量值密切相关。 相似文献
6.
本文采用1884—1984年西北太平洋台风资料[1],1949—1980年西北太平洋台风年鉴[2],探讨了西北太平洋台风发生频数的时空分布主要特征,揭示了E1 Nino年西北太平洋台风发生位置的异常情况。得出:1.台风源地中心在140—145°E,8—12°N;2.从台风发生频数的3年滑动平均曲线来看,波谷之间相隔为6—7年,波峰之间多数相隔为5年或8年;3.台风高频区(不论经度带或纬度带)有明显的季节变化;4.台风发生时海温在27℃以上、30℃以下;5.在E1 Nino年,台风高频区比常年台风高频区偏东。并对高频区异常的原因作了初步分析。 相似文献
7.
基于近40 a NCEP/NCAR再分析月平均高度场、风场、涡度场、垂直速度场以及NOAA重构的海面温度(sea surface temperature,SST)资料和美国联合台风预警中心(Joint Typhoon Warning Center,JTWC)热带气旋最佳路径资料,利用合成分析方法,研究了前期春季及同期夏季印度洋海面温度同夏季西北太平洋台风活动的关系。结果表明:1)前期春季印度洋海温异常(sea surface temperature anomaly,SSTA)尤其是关键区位于赤道偏北印度洋和西南印度洋地区对西北太平洋台风活动具有显著的影响,春季印度洋海温异常偏暖年,后期夏季,110°～180°E的经向垂直环流表现为异常下沉气流,对应风场的低层低频风辐散、高层辐合的形势,这种环流形势使得低层水汽无法向上输送,对流层中层水汽异常偏少,纬向风垂直切变偏大,从而夏季西北太平洋台风频数偏少、强度偏弱,而异常偏冷年份则正好相反。2)春季印度洋异常暖年,西北太平洋副热带高压加强、西伸;而春季印度洋异常冷年,后期夏季西北太平洋副热带高压减弱、东退,这可能是引起夏季西北太平洋台风变化的另一原因。 相似文献
8.
基于SODA再分析资料和TAO资料,利用EOF和统计分析等方法,分别研究了赤道太平洋海面纬向风应力异常和赤道太平洋上层纬向流异常的时空特征及其对西太平洋暖池纬向运移的影响。结果显示,赤道太平洋海面纬向风应力距平场第一模态具有2—5年的年际变化特征,其时空分布呈东、西向的反位相变化;而赤道太平洋上层纬向流距平场的第一模态则为1—2年的年和年际变化,且整个研究区域位相统一。纬向风应力和纬向流异常变化最显著的区域都在赤道中太平洋。相关分析显示,赤道中太平洋海面纬向风应力异常和赤道西太平洋上层纬向流异常分别对西太平洋暖池纬向运移有约2个月和4—6个月的超前影响,是暖池纬向运移的两个重要动力因素。回归分析表明,赤道中太平洋海面纬向风应力异常和赤道西太平洋上层纬向流异常对西太平洋暖池纬向运移有很好的预报意义。 相似文献
9.
王赐震 《山东海洋学院学报》1980,10(2):45-50
本文在基于大西洋飓风和西北太平洋台风的大量实测资料建立的轴对称、稳定状态台风摸式的基础上对涡度转移所导致的台风的西向运动速度(本文称作β速度)进行了分析。量级概算说明对于尺度较大的台风这一β速度是不可忽视的。文中并把它与台风内力的效果进行了比较． 相似文献
10.
2023年夏季（6—8月）大气环流特征为：北半球极涡呈偶极型分布,极涡强度较常年偏弱,欧亚地区及西北太平洋500 hPa槽脊位置与常年相近,副热带高压较常年平均偏西且略偏南,强度偏强,范围偏大。6 月,我国东部和北部近海海域出现3次海雾过程,7月和8月无大范围海雾过程。西北太平洋和南海生成台风10个,个数较常年同期偏少,平均极值强度显著偏强。6月生成1个远海转向台风;7月生成3个台风,其中2个台风登陆我国;8月台风活动频繁,生成台风6个,其中有2个在9月登陆我国。全球其他海域有20个编号的热带气旋生成。我国近海出现6次8级以上大风过程,其中热带气旋影响5次,江淮气旋入海影响1次。浪高超过2.0 m 的大浪过程发生12次。西北太平洋和南海海面温度较常年平均偏高,台风活动对海浪和海面温度分布影响显著。 相似文献
11.
Mansour Ioualalen Yoshinobu Wakata Yoshikazu Kawahara Yves Gouriou David Varillon 《Journal of Oceanography》2003,59(1):105-111
The sea surface salinity (SSS) derived from a network developed at Institut de Recherche pour le Développement (IRD/Nouméa)
has been analyzed during the period 1995–1998 in the tropical western Pacific. The measurements were made with thermosalinographs
installed on merchant ships selected for their regularity and routes. The western tropical Pacific was sampled mainly along
three regular routes across the equator leading to an average of a one month frequency. We analyze here how such a network
can be efficient in monitoring the SSS at time scales longer than one month. For this purpose we have used results derived
from the Princeton Ocean Model (POM) which is forced by the surface flux of National Centers for Environmental Prediction
(NCEP) reanalysis data. The interannual variability of the simulated SSS exhibits very similar features to (sub-sampled) observations
despite its being weakly damped to a climatology in order to avoid biases. Even smaller time scale phenomena can be simulated,
like the erosion/reconstruction of the region composed of low density waters lying within the Pacific warm pool. The agreement
between the observational data and the simulations indicate that the network sampling is sufficient to monitor the SSS variability
of the western tropical Pacific from three-month to interannual time scales.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
12.
Analysis of the first 26 months of data from the Aquarius satellite confirms the existence of a sharp sea surface salinity (SSS) front along the equator in the western equatorial Pacific. Following several earlier studies, we use the longitudinal location of the 34.8-psu isohaline as an index, termed Niño-S34.8, to measure the zonal displacement of the SSS front and consequently the eastern edge of the western Pacific warm pool. The on-going collection of the Array for Real-time Geostrophic Oceanography (ARGO) program data shows high correlations between Niño-S34.8 and the existing indices of El Niño, suggesting its potential important role in ENSO evolution. Further analysis of the ARGO data reveals that SSS variability in the southeastern tropical Pacific is crucial to identify the type of El Niño. A new SSS index, termed the southeastern Pacific SSS index (SEPSI), is defined based on the SSS variability in the region (0°–10°S, 150°–90°W). The SEPSI is highly correlated with the El Niño Modoki index, as well as the Trans-Niño index, introduced by previous studies. It has large positive anomalies during central Pacific El Niño or El Niño Modoki events, as a result of enhanced zonal sea surface temperature gradients between the central and eastern tropical Pacific, and can be used to characterize the type of El Niño. The processes that possibly control these SSS indices are also discussed. 相似文献
13.
Limitations in sea surface salinity (SSS) observations and timescale separation methods have led to an incomplete picture of the mechanisms of SSS decadal variability in the tropical Pacific Ocean, where the El Niño Southern Oscillation (ENSO) dominates. Little is known regarding the roles of the North Pacific Gyre Oscillation (NPGO) and the Pacific Decadal Oscillation (PDO) in the large-scale SSS variability over the tropical basin. A self-organizing map (SOM) clustering analysis is performed on the intrinsic mode function (IMF) maps, which are decomposed from SSS and other hydrological fields by ensemble empirical mode decomposition (EEMD), to extract their asymmetric features on decadal timescales over the tropical Pacific. For SSS, an anomalous pattern appeared during 1997 to 2004, a period referred to as the anomalous late 1990s, when strong freshening prevailed in large areas over the southwestern basin and moderate salinization occurred in the western equatorial Pacific. During this period, the precipitation and surface currents were simultaneously subjected to anomalous fluctuations: the precipitation dipole and zonal current divergence along the equator coincided with the SSS increase in the far western equatorial Pacific, while the weak zonal current convergence in the southwestern basin and large-scale southward meridional currents tended to induce SSS decreases there. The dominant decadal modes of SSS and sea surface temperature (SST) in the tropical Pacific both resemble the NPGO but occur predominantly during the negative and positive NPGO phases, respectively. The similarities between the NPGO and Central Pacific ENSO (CP-ENSO) in their power spectra and associated spatial patterns in the tropics imply their dynamical links; the correspondence between the NPGO-like patterns during negative (positive) phases and the CP La Niña (CP El Niño) patterns for SSS is also discussed. 相似文献
14.
海洋盐度在水循环、海洋环流、海洋生态系统、全球天气和气候变化等方面起着至关重要的作用。然而,受观测的限制,以往对海洋盐度的研究相对匮乏,对其进行预报的工作更为少见。本文采用线性马尔可夫模型对印度洋海表面盐度(sea surface salinity,SSS)开展初步的预报工作。根据混合层盐度收支方程,选择海表面高度(sea surface height,SSH)、海表面温度(sea surface temperature,SST)、SSS等物理量的异常值作为模型的组成部分,对印度洋SSS开展预报工作。结果表明,马尔可夫模型可提前9个月对印度洋SSS进行较好的预报。此外,南太平洋海表面温度异常(sea surface temperature anomaly,SSTA),海表面高度异常(sea surface height anomaly,SSHA)和印度洋偶极子(Indian Ocean dipole,IOD)系数等遥相关因素的加入可将线性马尔可夫预报对印度洋SSS的预报效果(相关系数)平均提高10%。利用改进的模型对印度洋SSS进行提前1～11个月的“实时”预测,得出预报的SSS时空变... 相似文献
15.
Isolation of sea surface salinity maps on various timescales in the tropical Pacific Ocean 总被引：1，自引：0，他引：1
Jian Chen Ren Zhang Huizan Wang Yuzhu An Peng Peng Weitao Zhang 《Journal of Oceanography》2012,68(5):687-701
To isolate sea surface salinity (SSS) maps on seasonal, ENSO, decadal, and long-term trend timescales in the tropical Pacific Ocean, the ensemble empirical mode decomposition (EEMD) is applied on an SSS data set covering 1950–2009, concerning three key regions including the western equatorial Pacific Warm Pool (WP), South Pacific Convergence Zone (SPCZ), and Inter Tropical Convergence Zone (ITCZ); then a self-organizing map is performed on the intrinsic mode function maps decomposed by the EEMD, concerning the whole basin. The ENSO and decadal signals concern mainly the western Pacific, in contrast to the seasonal signal mostly notable in the east. (1) The modulated annual cycle has smaller (larger) amplitudes during El Ni?o (La Ni?a) years and later appearance of minima during El Ni?o years; one unique annual cycle is observed at the northwestern edge of the ITCZ lagging the well-known ITCZ cycle by ~3?months. (2) The pronounced 1999–2001 SSS-related La Ni?a event in the SPCZ was reinforced twice by the decadal shift in the 1990s; the eastern Pacific and central Pacific ENSO-related SSS features are compared. (3) The contrasted anomalies between the western equatorial and non-equatorial regions were pronounced during 1977–1996, whereas they were less pronounced during 1971–1976, 2005–2008, and a roughly opposite pattern appeared with strong and abrupt decrease shift prevailing in large areas over the southwestern basin during 1997–2004. (4) The freshening at the western equator and the saltening located east of the SPCZ SSS front together amplify the geographical SSS contrasts exhibited by the WP and SPCZ SSS fronts. 相似文献
16.
热带太平洋障碍层厚度的时空特征分析 总被引：2，自引：0，他引：2
利用中国Argo实时数据中心提供的9 a(2000—2008年)网格化Argo剖面浮标温、盐数据(G Argo),分析热带太平洋障碍层厚度的气候态分布和低频变化特征。气候平均结果表明,较厚的障碍层主要出现于西太平洋暖池区,并有3条纬向障碍层带状分布,从暖池出发向东延伸至120°W,分别位于以15°N,5°N和12°S为中心的纬度带上。经验正交函数(EOF)基本模态分析表明,热带太平洋障碍层低频振荡以季节和年际变化为主,在季节尺度上主要表现为15°N和12°S障碍层纬度带呈反相变化,都在当地冬季最大,夏季最小;在年际尺度上则主要表现为暖池东边界附近障碍层与厄尔尼诺南方涛动(ENSO)相关的变化,以及暖池中部障碍层与热带准2 a周期振荡(TBO)相关的变化。 相似文献
17.
西太平洋暖池变异及其对西太平洋次表层海温场的影响 总被引：9，自引：0，他引：9
应用热带太平洋上层XBT温度资料,分析研究了西太平洋暖池区(0°～16°N,125°～145°E)上层海洋的变化特征以及与西太平洋次表层海温场之间的关系.研究表明,西太平洋暖池区的垂向温度存在显著的年际变化,尤其在次表层(120～200m)的变化最为明显.西太平洋暖池区的次表层冷暖信号明显早于西太平洋次表层的海温异常.分析发现,西太平洋暖池区的海温异常是导致整个西太平洋次表层海温场变异的关键区,当西太平洋暖池区的次表层冷暖信号加强时,3～4个月后西太平洋海温场出现大范围的冷暖异常. 相似文献
18.
Hydrography of the eastern tropical Pacific: A review 总被引：3，自引：10，他引：3
19.
Using sea surface salinity(SSS)observation from the soil moisture active passive(SMAP)mission,we analyzed the spatial distribution and seasonal variation of SSS around Changjiang River(Yangtze River)Estuary for the period of September 2015 to August 2018.First,we found that the SSS from SMAP is more accurate than soil moisture and ocean salinity(SMOS)mission observation when comparing with the in situ observations.Then,the SSS signature of the Changjiang River freshwater was analyzed using SMAP data and the river discharge data from the Datong hydrological station.The results show that the SSS around the Changjiang River Estuary is significantly lower than that of the open ocean,and shows significant seasonal variation.The minimum value of SSS appears in July and maximum SSS in December.The root mean square difference of daily SSS between SMAP observation and in situ observation is around 3 in both summer and winter,which is much lower than the annual range of SSS variation.In summer,the diffusion direction of the Changjiang River freshwater depicted by SSS from SMAP is consistent with the path of freshwater from in situ observation,suggesting that SMAP observation may be used in coastal seas in monitoring the diffusion and advection of freshwater discharge. 相似文献
20.
《Oceanologica Acta》1999,22(3):249-263
Mean conditions, seasonal, and ENSO-related (El Niño Southern Oscillation) variability in the vicinity of Wallis, Futuna, and Samoa islands (13°–15° S, 180°–170° W) over the 1973–1995 period are analysed for wind pseudo-stress, satellite-derived and in situ precipitation, sea surface temperature (SST) and salinity (SSS), sea level, and 0–450 m temperature and geostrophic current. The mean local conditions reflect the presence of the large scale features such as the western Pacific warm pool, the South Pacific Convergence Zone (SPCZ), and the South Pacific anticyclonic gyre. The seasonal changes are closely related to the meridional migrations of the SPCZ, which passes twice a year over the region of study. During the warm phase of ENSO (El Niño), we generally observe saltier-than-average SSS (of the order of 0.4), consistent with a rainfall deficit (0.4 m yr−1), a hint of colder-than-average surface temperature is also identified in subsurface (0.3°C), a weak tendency for westward geostrophic current anomalies (2 cm s−1 at the surface), a sea level decrease (5–10 cm), together with easterly (5 m2s−2) and well marked southerly (10 m2s−2) wind pseudo-stress anomalies. Anomalies of similar magnitude, but of opposite sign, are detected during the cold phase of ENSO (La Niña). While these ENSO-related changes apply prior to the 1990s, they were not observed during the 1991–1994 period, which appears atypical. 相似文献