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1.
Muhammad Mubashar Dogar Fred Kucharski Syed Azharuddin 《Journal of Earth System Science》2017,126(2):30
ENSO is considered as a strong atmospheric teleconnection that has pronounced global and regional circulation effects. It modifies global monsoon system, especially, Asian and African monsoons. Previous studies suggest that both the frequency and magnitude of ENSO events have increased over the last few decades resulting in a need to study climatic impacts of ENSO magnitude both at global and regional scales. Hence, to better understand the impact of ENSO amplitude over the tropical and extratropical regions focussing on the Asian and African domains, ENSO sensitivity experiments are conducted using ICTPAGCM (‘SPEEDY’). It is anticipated that the tropical Pacific SST forcing will be enough to produce ENSO-induced teleconnection patterns; therefore, the model is forced using NINO3.4 regressed SST anomalies over the tropical Pacific only. SPEEDY reproduces the impact of ENSO over the Pacific, North and South America and African regions very well. However, it underestimates ENSO teleconnection patterns and associated changes over South Asia, particularly in the Indian region, which suggests that the tropical Pacific SST forcing is not sufficient to represent ENSO-induced teleconnection patterns over South Asia. Therefore, SST forcing over the tropical Indian Ocean together with air–sea coupling is also required for better representation of ENSO-induced changes in these regions. Moreover, results obtained by this pacemaker experiment show that ENSO impacts are relatively stronger over the Inter-Tropical Convergence Zone (ITCZ) compared to extratropics and high latitude regions. The positive phase of ENSO causes weakening in rainfall activity over African tropical rain belt, parts of South and Southeast Asia, whereas, the La Niña phase produces more rain over these regions during the summer season. Model results further reveal that ENSO magnitude has a stronger impact over African Sahel and South Asia, especially over the Indian region because of its significant impact over the tropical Atlantic and the Indian Ocean through Walker circulation. ENSO-induced negative (positive) NAO-like response and associated changes over Southern Europe and North Africa get significantly strong following increased intensity of El Niño (La Niña) in the northern (southern) hemisphere in the boreal winter (summer) season. We further find that ENSO magnitude significantly impacts Hadley and Walker circulations. The positive phase of ENSO (El Niño) overall strengthens Hadley cell and a reverse is true for the La Niña phase. ENSO-induced strengthening and weakening of Hadley cell induces significant impact over South Asian and African ITCZ convective regions through modification of ITCZ/monsoon circulation system. 相似文献
2.
This study assesses retrospective decadal prediction skill of Sea Surface Temperature (SST) variability in initialized climate prediction experiments (INT) with the Beijing Climate Center Climate System Model (BCC_CSM1.1). Ensemble forecasts were evaluated using observations, and compared to an ensemble of uninitialized simulations (NoINT). The results show as follows: ①The warming trend of global mean SST simulated by the INT runs is closer to the observation than that in the NoINT runs.②The INT runs show high SST prediction skills over broad regions of tropical Atlantic, western tropical Pacific and tropical Indian Oceans. ③ In the North Pacific and the east-central tropical Pacific Ocean, the prediction skills are very weak, and there are few improvements coming from the initialization in the INT runs. ④ In the southern Indian Ocean, the prediction skills of the INT runs are significantly larger than that of the NoINT runs, with the maximum skill at the 3~6 and 4~7 years lead time. The above-mentioned conclusions are similar to the results of other climate models. However, the prediction skill in the North Atlantic Ocean is much lower than that of other models, especially in the subpolar region. The low skills in the Atlantic Ocean may be attributed to the misrepresentation of the lead-lag relationship between the Atlantic meridional heat transport and the SST in the BCC_CSM1.1. 相似文献
3.
Miriam Pfeiffer Wolf-Christian Dullo Jens Zinke Dieter Garbe-Schönberg 《International Journal of Earth Sciences》2009,98(1):53-66
In order to assess the fidelity of coral Sr/Ca for quantitative reconstructions of sea surface temperature variations, we have generated three monthly Sr/Ca time series from Porites corals from the lagoon of Peros Banhos (71°E, 5°S, Chagos Archipelago). We find that all three coral Sr/Ca time series are well correlated with instrumental records of sea surface temperature (SST) and air temperature. However, the intrinsic variance of the single-core Sr/Ca time series differs from core to core, limiting their use for quantitative estimates of past temperature variations. Averaging the single-core data improves the correlation with instrumental temperature (r > 0.7) and allows accurate estimates of interannual temperature variations (~0.35°C or better). All Sr/Ca time series indicate a shift towards warmer temperatures in the mid-1970s, which coincides with the most recent regime shift in the Pacific Ocean. However, the magnitude of the warming inferred from coral Sr/Ca differs from core to core and ranges from 0.26 to 0.75°C. The composite Sr/Ca record from Peros Banhos clearly captures the major climatic signals in the Indo-Pacific Ocean, i.e. the El Niño–southern oscillation and the Pacific decadal oscillation. Moreover, composite Sr/Ca is highly correlated with tropical mean temperatures (r = 0.7), suggesting that coral Sr/Ca time series from the tropical Indian Ocean will contribute to multi-proxy reconstructions of tropical mean temperatures. 相似文献
4.
Ensemble seasonal integrations are carried out with the COLA GCM, with a view to understand the dynamical connection between warm SST anomalies in the equatorial central-eastern Pacific Ocean and the upper level stationary wave anomalies seen during drought years over the Indian summer monsoon region. In addition, experiments with and without orography are performed in order to examine the role of the Himalayas in modulating the El Niño induced stationary wave anomalies over the summer monsoon region. The GCM simulations show a statistically significant weakening of the summer monsoon activity over India in response to the SST forcing in the equatorial Pacific Ocean. This weakening of the summer monsoon appears to be largely related to modifications of the local Hadley and Walker cells over the summer monsoon region. In addition, it is seen that the anomalous ENSO divergent forcing over the tropical Pacific Ocean can act as a potential source for Rossby wave dispersion. Here one finds the possibility of meridionally propagating Rossby waves, which emanate from the ENSO forcing region, to interact with the subtropical westerlies and generate anomalous highs and lows in the subtropics and extratropics. The quasi-stationary perturbations seen over west Asia, Pakistan and northwest India during drought years, seem to be generated by the above mechanism. An alternate mechanism that could be important for the persistence of the quasi-stationary perturbations seems to be based on the dynamic excitation of middle latitude normal modes which can extract energy from the zonally varying unstable basic flow. It is seen from the GCM simulations, that the Himalayan orography plays a crucial role in anchoring the El Niño induced extratropical westerly troughs far to the west in the high latitude belt. In the absence of orography it is seen that the ENSO induced extra-tropical cyclonic anomalies tend to intrude southward into the monsoon region thereby destroying the regional scale circulations completely. Another effect due to the Himalayas is to generate lee waves on the eastern side of the topographic barrier which encircle the globe in the subtropics and midlatitudes. 相似文献
5.
Research efforts focused on assessing the potential for changes in tropical cyclone activity in the greenhouse-warmed climate
have progressed since the IPCC assessment in 1996. Vulnerability to tropical cyclones becoming more pronounced due to the
fastest population growth in tropical coastal regions makes it practically important to explore possible changes in tropical
cyclone activity due to global warming. This paper investigates the tropical cyclone activity over whole globe and also individually
over six different ocean basins. The parameters like storm frequency, storm duration, maximum intensity attained and location
of formation of storm have been examined over the past 30-year period from 1977 to 2006. Of all, the north Atlantic Ocean
shows a significant increasing trend in storm frequency and storm days, especially for intense cyclones. Lifetime of intense
tropical cyclones over south Indian Ocean has been increased. The intense cyclonic activity over north Atlantic, south-west
Pacific, north and south Indian Ocean has been increased in recent 15 years as compared to previous 15 years, whereas in the
east and west-north Pacific it is decreased, instead weak cyclone activity has been increased there. Examination of maximum
intensity shows that cyclones are becoming more and more intense over the south Indian Ocean with the highest rate. The study
of the change in the cyclogenesis events in the recent 15 years shows more increase in the north Atlantic. The Arabian Sea
experiences increase in the cyclogenesis in general, whereas Bay of Bengal witnesses decrease in these events. Shrinking of
cyclogenesis region occurs in the east-north Pacific and south-west Pacific, whereas expansion occurs in west-north Pacific.
The change in cyclogenesis events and their spatial distribution in association with the meteorological parameters like sea
surface temperature (SST), vertical wind shear has been studied for Indian Ocean. The increase in SST and decrease in wind
shear correspond to increase in the cyclogenesis events and vice versa for north Indian Ocean; however, for south Indian Ocean,
it is not one to one. 相似文献
6.
The impact of realistic representation of sea surface temperature (SST) on the numerical simulation of track and intensity
of tropical cyclones formed over the north Indian Ocean is studied using the Weather Research and Forecast (WRF) model. We
have selected two intense tropical cyclones formed over the Bay of Bengal for studying the SST impact. Two different sets
of SSTs were used in this study: one from TRMM Microwave Imager (TMI) satellite and other is the weekly averaged Reynold’s
SST analysis from National Center for Environmental Prediction (NCEP). WRF simulations were conducted using the Reynold’s
and TMI SST as model boundary condition for the two cyclone cases selected. The TMI SST which has a better temporal and spatial
resolution showed sharper gradient when compared to the Reynold’s SST. The use of TMI SST improved the WRF cyclone intensity
prediction when compared to that using Reynold’s SST for both the cases studied. The improvements in intensity were mainly
due to the improved prediction of surface latent and sensible heat fluxes. The use of TMI SST in place of Reynold’s SST improved
cyclone track prediction for Orissa super cyclone but slightly degraded track prediction for cyclone Mala. The present modeling
study supports the well established notion that the horizontal SST gradient is one of the major driving forces for the intensification
and movement of tropical cyclones over the Indian Ocean. 相似文献
7.
INTERACTION BETWEEN THE ENSO AND ASIAN MONSOON RECORDED IN DASUOPU ICE CORE FROM HIMALAYAS 相似文献
8.
9.
Fan Wang Chuanyu Liu Shijian Hu Shan Gao Fan Jia Linlin Zhang Jianing Wang Junqiao Feng 《地球科学进展》2018,33(8):775-782
This study focused on the warm pool-cold tongue confluence region (WCCR) in the central tropical Pacific Ocean where the warm and fresh water from the warm pool encounters with cold and saline water from the cold tongue. The WCCR is characterized by strong surface salinity front, shallow mixed layer and thick barrier layer. The WCCR is the key area for the development of different types of El Ni?o, and also the area with significant systematic bias in climate models. In order to reveal what role the structure and variability of salinity will play in the ocean dynamic and thermal conditions, and the cycle of the ENSO, a key project was approved by the National Natural Science Foundation of China (NSFC) in July, 2017. The key scientific issues that will be addressed in the project are as follows: ①to depict the three-dimensional structure and variability of salinity in the WCCR; ②to reveal the mechanism for the variability of salinity front and barrier layer; and ③to illustrate the main processes that control the impact of salinity on the upper-ocean variation in the tropical Pacific and the cycle of the ENSO. The present study will improve our understanding of the tropical ocean dynamics and ENSO dynamics, and will enhance the prediction skill of the ENSO. 相似文献
10.
文章利用Zhao等的模拟结果,进一步研究了在末次盛冰期(LGM)情景下汪品先和CLIMAP两种重建海洋表面温度(SST)资料差异对亚洲夏季风的影响。模拟结果表明:在LGM情景下西太平洋海域SST资料的不同对模拟的亚洲夏季风有着十分重要的作用。夏季,与CLGM方案相比,在WLGM方案中,当热带西太平洋SST较暖时,印度地区的大气热量出现显著增加,大气热量的这种变化,使得南非高压、南印度洋经向Hadley环流加强,伴随着索马里越赤道气流加强,也导致了印度季风区纬向季风环流的加强,从而造成了印度夏季风增强、降水增多;与较暖的热带西太平洋相对应,澳大利亚高压和120°E附近越赤道气流减弱,东亚季风区20°N以南经向季风环流加强、20°N以北经向季风环流减弱,指示着一个强的南海夏季风和较弱东亚副热带大陆夏季风。 相似文献
11.
The role of low-frequency intraseasonal oscillations in the anomalous Indian summer monsoon rainfall of 2002 总被引：1，自引：0，他引：1
We analyze the dynamical features and responsible factors of the low-frequency intraseasonal time scales which influenced
the nature of onset, intensity and duration of active/break phases and withdrawal of the monsoon during the anomalous Indian
summer monsoon of 2002 — the most severe drought recorded in recent times. During that season, persistent warm sea surface
temperature anomalies over the equatorial Indian Ocean played a significant role in modulating the strength of the monsoon
Hadley circulation. This in turn affected the onset and intense break spells especially the long break during the peak monsoon
month of July. Strong low-frequency intraseasonal modulations with significant impact on the onset and active/break phases
occurred in 2002 which were manifested as a good association between low-frequency intraseasonal oscillations and the onset
and active/break spells. Further, SST anomalies over the equatorial Indo-Pacific region on low-frequency intraseasonal time
scales were found to affect the equatorial eastward and thereby off-equatorial northward propagations of enhanced convection
over the Indian region. These propagations in turn modulated the active/break cycle deciding the consequent severity of the
2002 drought. 相似文献
12.
Monsoon onset over Kerala (India) which occurs every year is a major climatic phenomenon that involves large scale changes in wind, rainfall and sea surface temperature (SST). Over the last 150 years, the date of monsoon onset over Kerala (DMOK) has varied widely, the earliest being 11 May, 1918 and the most delayed being 18 June, 1972. DMOK has a long term (1870–2014) mean of 01 June and standard deviation of 7–8 days. We have studied the inter-annual and decadal time scale variability of DMOK and their relation with SST. We found that SST anomalies of large spatial scale similar to those in El Nino/La Nina are associated with the inter-annual variability in DMOK. Indian Ocean between latitudes \(5^{\circ }\hbox {S}\) and \(20^{\circ }\hbox {N}\) has two episodes of active convection associated with monsoon onset over Kerala (MOK), one around DMOK and the other about six weeks earlier (called pre-monsoon rain peak or bogus monsoon onset) and in between a two week period of suppressed convection occurs over north Indian Ocean. A prominent decadal time scale variability was found in DMOK having large and statistically significant linear correlation with the SST gradient across the equator over Indian and Pacific oceans, the large correlation persisting for several months prior to the MOK. However, no linear trend was seen in DMOK during the long period from 1870 to 2014. 相似文献
13.
Using the HadISST data from 1880 to 2009, removed the signal of global warming in one hundred year. The results show that, there were the significant interannual and interdecadal oscillation signal at the eastern Pacific and north Pacific and north Atlantic, especially the decadal oscillation in the south of eastern equatorial Pacific cannot be ignored. We found there are three major global-scale signals by using the Empirical Orthogonal Function (EOF) analysis on global sea surface temperature, the first mode is (ENSO-like/PDO-like) Pacific pattern, the second mode is (AMO-like) the north Atlantic pattern and the third mode is (ENSO Modoki-like/CP ENSO-like) Center Pacific Ocean pattern. In particular, the third mode is the performance of Center Pacific El Niño-Southern Oscillation in the global mode. There are significant signals in interannual and interdecadal scales, in the unfiltered conditions, the three modes can explain 34% of total variance contribution. Above the interdecadal scale, the sum of three modes variance contribution is 61%. In various time scales, the three signals and the average global temperature has a connection, especially the influence of the first and second mode is the most important, in the decadal scale, the sum of the first and second modal variance contribution is 50%. Since 2005, there is no significant signal of global warming may be associated with the simultaneous decline of the first two modes. 相似文献
14.
作为全球接受太阳辐射最多、表层海水温度最高的区域,西太平洋暖池区通过厄尔尼诺-南方涛动(El Niño-Southern Oscillation,ENSO)和季风等过程影响着全球气候的变化。越来越多的沉积记录证明,在地质历史时期西太平洋暖池也存在类似于现代ENSO过程的“类ENSO式”变化。而目前类ENSO式变化与冰期—间冰期旋回之间的响应关系和驱动机制及其与东亚季风的关联仍存在争议。本文利用位于暖池核心区的B10岩心浮游有孔虫氧同位素、Mg/Ca(质量分数比)和黏土矿物参数重建了暖池区氧同位素8期以来的古气候记录,并结合已有的热带海表温度记录、中国石笋氧同位素和南大洋地区海表温度记录,研究了西太平洋暖池冰期旋回中类ENSO状态的演化规律及其与东亚季风的关系,并探讨了暖池区类ENSO演化的驱动机制。结果发现:冰期时,西太平洋暖池区温跃层变浅,赤道东、西太平洋温差减小,同时,东亚夏季风减弱,暖池区降水量相对减少,与现代El Niño时期气候态类似;间冰期时,西太平洋暖池区温跃层加深,赤道东、西太平洋温差增大,东亚冬夏季风增强,暖池区降水量相对增加,与现代La Niña时期气候态类似。频谱分析结果表明,西太平洋暖池区海表温度的变化具有偏心率周期(96 ka)。冰消期时,低纬度太阳辐射量的增加,增大了纬向上的SST梯度,并使得次表层海水储存了更多的热量,积累的热量会通过调节次表层环流向暖池区的热传输,最终调控赤道太平洋地区Walker环流强度和ENSO活动的长期变化。而冰期时,南大洋地区降温所引起的东南信风和大洋环流异常可能对类ENSO式起到调控的作用。 相似文献
15.
利用美国NCAR CAM3大气环流模式,分析了末次盛冰期（LGM）两个不同的热带海表温度重建方案中,北半球冬季热带中、西太平洋对流活动及大气环流对暖池外（赤道东太平洋和热带大西洋）热带SST异常的敏感性。结果表明： 1）SST异常首先引起大气环流的改变。 赤道东太平洋对流层下沉增强,而作为经向补偿,副热带东太平洋上升运动增强,其中南半球尤为明显,同时南半球热带中、西太平洋上升运动增强,加剧了该区纬向逆时针环流,说明冰期热带海气耦合过程受气候背景场（如SST）影响很大; 2）大气环流格局改变引起热带中西太平洋的大气加热、对流活动、表层风场及降雨的巨大变化。 140°E以西的婆罗洲和菲律宾区域,总的大气加热减少是由于对流与辐射加热减少所致,对应于该区风场辐散和降雨减少; 而140°E以东的南半球热带中、西太平洋,大气吸收热量增加,对流与辐射加热均增强,总降雨量也随之增加,反映该区赤道辐合带南移并增强。该项研究为探索热带太平洋在冰期/间冰期旋回中的古海洋学变化提供了新的数据支撑。此外,不同重建SST对赤道辐合带的影响比较大,因此利用重建SST进行数值模拟或者利用耦合模式研究LGM热带海气相互作用时,应该十分重视全球热带SST分布特征。 相似文献
16.
研究晚全新世季风气候演变有助于进一步认识与预测未来季风区气候变化。太平洋东西两岸是全球季风集中分布的地区,已经有大量的古气候记录发表,但是缺乏对各个季风区气候突变事件以及整体变化趋势的对比研究。针对这一问题,选取亚洲季风区、印澳季风区、北美季风区、南美季风区11个洞穴石笋δ18O和1个湖泊Ti含量,对比研究各个记录在3.5~0.5 ka B.P.期间指示的夏季风变化特征。通过对比发现四大季风区的石笋δ18O在晚全新世整体上呈现偏正趋势,指示夏季风减弱;2次重要的气候突变事件1.5 ka B.P.和2.7 ka B.P.弱夏季风事件在各个季风区内均有表现;同时也记录了一系列十年际-百年际尺度的弱夏季风事件,表明太平洋东西两岸和南北半球的夏季风都有减弱的趋势,这与先前研究认为的南北半球呈现"see-saw"模式表现出不一样的特征。晚全新世以来ENSO(El Nino-Southern Oscillation)活动的增强对太平洋东西两岸南北半球夏季风减弱具有重要影响。在El Nino事件发生时,Walker环流减弱,而且它的上升支向东移动远离西太平洋暖池,西太平洋副热带高压增强并向西移动,导致亚洲夏季风减弱。Walker环流的东移也会使得印度尼西亚-太平洋暖池(Indo-Pacific Warm Pool,简称IPWP)海温下降,热带季节内震荡减弱致使印澳夏季风减弱;此外,El Nino事件发生时,赤道东太平洋海水温度上升导致东西太平洋海水温度梯度减弱,在此状态下南美季风区低空急流(Low Level Jet,简称LLJ)减弱,导致南美夏季风减弱;同时,北美洲加勒比海低空急流增强,使得该季风区下沉气流增强,导致北美夏季风减弱。我们的研究表明,在晚全新世ENSO活动增强的状态下,太平洋东西两岸南北半球夏季风变化可能都呈现减弱趋势。 相似文献
17.
Gopinadh Konda J S Chowdary G Srinivas C Gnanaseelan Anant Parekh Raju Attada S S V S Rama Krishna 《Journal of Earth System Science》2018,127(4):46
In this study Tropospheric Biennial Oscillation (TBO) and south Asian summer monsoon rainfall are examined in the National Centers for Environmental Prediction (NCEP) Climate Forecast System (CFSv2) hindcast. High correlation between the observations and model TBO index suggests that the model is able to capture most of the TBO years. Spatial patterns of rainfall anomalies associated with positive TBO over the south Asian region are better represented in the model as in the observations. However, the model predicted rainfall anomaly patterns associated with negative TBO years are improper and magnitudes are underestimated compared to the observations. It is noted that positive (negative) TBO is associated with La Niña (El Niño) like Sea surface temperature (SST) anomalies in the model. This leads to the fact that model TBO is El Niño-Southern Oscillation (ENSO) driven, while in the observations Indian Ocean Dipole (IOD) also plays a role in the negative TBO phase. Detailed analysis suggests that the negative TBO rainfall anomaly pattern in the model is highly influenced by improper teleconnections allied to IOD. Unlike in the observations, rainfall anomalies over the south Asian region are anti-correlated with IOD index in CFSv2. Further, summer monsoon rainfall over south Asian region is highly correlated with IOD western pole than eastern pole in CFSv2 in contrast to the observations. Altogether, the present study highlights the importance of improving Indian Ocean SST teleconnections to south Asian summer rainfall in the model by enhancing the predictability of TBO. This in turn would improve monsoon rainfall prediction skill of the model. 相似文献
18.
应用1951-2001年ENSO特征指数(NINO1+2、NINO3、NINO4、NINO3.4、SOI)和1973-1998年南极海冰北界范围以及1950-2001年SODA海洋温度资料,分析探讨了ENSO循环过程与南极海冰之间的关系,研究了南大洋和太平洋海表温度与南极海冰之间的内在联系。结果表明,南极海冰变化与ENSO循环过程存在一定联系,特别是东南极海冰的变化与ENSO循环过程较为密切。这种遥相关关系表明,ENSO循环过程不仅与热带海洋自身的海 气相互作用存在密切关系,而且与南极海冰之间也存在一定的联系。当东南极海冰范围出现异常增大和减小时,在时滞一年之后,NINO循环指数将出现减弱和加强,而南方涛动指数将出现加强和减弱。这种相关关系的机制是通过大洋环流这一载体将异常海温向北输送来实现的。南极海冰范围的异常增加或减少,会直接影响南极绕极流的冷暖结构进而影响经向水体输送的异常,从而导致热带和副热带太平洋上层海温场的异常变化,对ElNino和LaNina事件的发生起到推动作用。 相似文献
19.
根据最近的研究结果,中国季风区同一洞穴或同一区域的晚全新世石笋氧同位素序列具有较好的重复性,表明中国季风区的石笋氧同位素短尺度(10～100年尺度,后同)变率所具有的信号强于噪音。通过进一步比较分析发现,一些石笋氧同位素记录虽然来自距离上千公里之遥的不同区域,但它们的波动形式在年代际至世纪尺度极其相似,说明它们是一致的大区域信号,但多数石笋氧同位素序列未能校准到本区器测的降水或温度记录上。通过与中国气候学家建立的各类季风指数比较,发现这些具有一致大区信号的中国石笋氧同位素序列与海平面气压差指数或海陆温差指数关系最好。再通过与印度洋－太平洋海域海平面气压差、以及许多海、气环流观测记录对比,发现中国季风区石笋氧同位素序列记录了20世纪后期最强的一次全球海、气环流年代际均值突变,由此初步确认了中国季风区石笋氧同位素短尺度变化的环流意义： 当印度洋海水和中东太平洋海水温度偏低时,西太平洋副热带高压偏北东缩而弱,中国季风区内来自印度洋的水汽份额增大,由于这些水汽的输送路程很远,导致中国季风区的雨水氧同位素及石笋氧同位素较轻; 而当印度洋海水和中东太平洋海水温度偏高时,西太平洋副热带高压偏南西伸而强,中国季风区内来自印度洋的远源水汽份额减少,而来自西太平洋的水汽份额增大,由于后者输送路程较近,导致中国季风区的雨水氧同位素及石笋氧同位素较重。由此命名瑞利分馏原理所决定、反映印度洋/太平洋海、气环流转变且大区域一致的中国季风区石笋氧同位素10～100年尺度变化为“环流效应”。 相似文献
20.
Based on the near-term climate prediction system of the Institute of Atmospheric Physics (hereafter IAP-DecPreS), we developed two distinct initialization schemes for the Coupled Global Climate Models (CGCM), FGOALS-s2. The first scheme used the Incremental Analysis Update (IAU) to assimilate gridded oceanic temperature and salinity data derived from the EN3 dataset. The second scheme used the merge of the ensemble optimal interpolation (EnOI) and IAU scheme (hereafter EnOI-IAU) to assimilate raw observational oceanic temperature and salinity profiles. The predictive skills of the decadal prediction experiments based on the two schemes were compared. Several metrics including temporal correlation and root mean square skills score indicate that the experiment based on the EnOI-IAU shows significantly higher predictive skills in the Sea Surface Temperature (SST) anomalies in the North Pacific associated with the Pacific Decadal Oscillation (PDO), than the experiment based on the IAU. In contrast, for the Atlantic Multi-Decadal Oscillation (AMO), the predictive skills of the experiment based on the EnOI-IAU are lower than that based on the IAU. The AMO has two activity centers, located in the subpolar and tropical North Atlantic. The skills of the experiment based on the EnOI are close to that based on the IAU in the tropical North Atlantic, while much lower than the latter in the extratropical region due to a false simulation of the warming trend in the region. 相似文献