This paper attempts to analyze in detail the remote influence of the Indian Ocean Basin warming on the Northwest Pacific(NWP) during the year of decaying El Ni o.Observation data and the Fast Ocean- Atmosphere coupled...This paper attempts to analyze in detail the remote influence of the Indian Ocean Basin warming on the Northwest Pacific(NWP) during the year of decaying El Ni o.Observation data and the Fast Ocean- Atmosphere coupled Model 1.5 were used to investigate the triggering conditions under which the remote influence is formed between the positive sea surface temperature(SST) anomaly in the North Indian Ocean and the Anomalous Northwest Pacific anticyclone(ANWPA).Our research show that it is only when there is a contributory background wind field over the Indian Ocean,i.e.,when the Indian Summer Monsoon(ISM) reaches its peak,that the warmer SST anomaly in the North Indian Ocean incites significant easterly wind anomalies in the lower atmosphere of the Indo-West tropical Pacific.This then produces the remote influence on the ANWPA.Therefore,the SST anomaly in the North Indian Ocean might interfere with the prediction of the East Asia Summer Monsoon in the year of decaying El Ni o.Both the sustaining effect of local negative SST anomalies in the NWP,and the remote effect of positive SST anomalies in the North Indian Ocean on the ANWPA,should be considered in further research.展开更多
Using 20 models of the Coupled Model Intercomparison Project Phase 5 （CMIP5）, the simulation of the Southwest Indian Ocean （SWIO） thermocline dome is evaluated and its role in shaping the Indian Ocean Basin （IOB...Using 20 models of the Coupled Model Intercomparison Project Phase 5 （CMIP5）, the simulation of the Southwest Indian Ocean （SWIO） thermocline dome is evaluated and its role in shaping the Indian Ocean Basin （IOB） mode following E1 Nifio investigated. In most of the CMIP5 models, due to an easterly wind bias along the equator, the simulated SWIO thermocline is too deep, which could further influence the amplitude of the interannual IOB mode. A model with a shallow （deep） thermocline dome tends to simulate a strong （weak） IOB mode, including key attributes such as the SWIO SST warming, antisymmetric pattern during boreal spring, and second North Indian Ocean warming during boreal summer. Under global warming, the thermocline dome deepens with the easterly wind trend along the equator in most of the models. However, the IOB amplitude does not follow such a change of the SWIO thermocline among the models; rather, it follows future changes in both ENSO forcing and local convection feedback, suggesting a decreasing effect of the deepening SWIO thermocline dome on the change in the IOB mode in the future.展开更多
Sea surface temperature anomaly(SSTA)is a major signal for prediction of summer precipitation in East Asia.The relationship between SSTA in the tropical oceans and summer precipitation in East Asia has been documented...Sea surface temperature anomaly(SSTA)is a major signal for prediction of summer precipitation in East Asia.The relationship between SSTA in the tropical oceans and summer precipitation in East Asia has been documented in many studies.However,the relationship between SSTA and late summer(July–August)precipitation(JAP)over Northeast China(NEC)on the interannual timescale has received little attention.In this study,we examine the relationship between Indian Ocean Basin warming(IOBW)anomalies in spring and the JAP in NEC since the early1960 s.A significant positive correlation is found between the spring IOBW index and JAP over NEC.The positive spring IOBW anomaly is followed by an anomalous anticyclone from Northwest Pacific to the Korean Peninsula.This anomalous anticyclone favors a significantly strong and northward western Pacific subtropical high(WPSH),which facilitates anomalous southerly winds over NEC and the transport of more water vapor into this region.Further analysis indicates that the spring IOBW anomalies have important impacts on the vertical air motion in the tropics and subtropics during the summer.Significant anomalous upward(downward)motion covering Indonesia(Northwest Pacific to the southern Korean Peninsula)occurs when the IOBW is in its positive phase,which favors the northward movement of the WPSH in late summer and more precipitation over NEC in July–August.Modulation of the atmospheric circulation by this mechanism further influences the JAP over NEC.展开更多
Recent studies have found a connection between Indian Ocean Basin Warming and the anomalous Northwest Pacific Anticyclone(ANPWA) during El Ni?o decaying year.This study focuses on the necessary condition for this conn...Recent studies have found a connection between Indian Ocean Basin Warming and the anomalous Northwest Pacific Anticyclone(ANPWA) during El Ni?o decaying year.This study focuses on the necessary condition for this connection by using observation and numerical simulation.The seasonal transition of the Indian Ocean sea surface wind is critical to the climatic effect of Indian Ocean Basin Warming.When the South Asian Summer Monsoon reaches its peak,the background wind becomes desirable for basin warming,which then affects the climate in the Northwest Pacific.Via the Kelvin waves and Ekman divergence,the wind anomalies exist in the lower atmosphere east of the Indian Ocean warm Sea Surface Temperature(SST) anomalies,and intensify and sustain the ANWPA throughout the El Nio decaying summer.This impact plays an important role in the inter-annual variability of the East Asian Summer Monsoon.展开更多
基金Supported by the National Basic Research Program of China(973 Program)(Nos.2010CB428504,2012CB956002)the National Natural Science Foundation of China(Nos.40906005,41105059,41065005,GYHY201106017,GYHY201306027)the National Key Technology Research and Development Program(No.2009BAC51B01)
文摘This paper attempts to analyze in detail the remote influence of the Indian Ocean Basin warming on the Northwest Pacific(NWP) during the year of decaying El Ni o.Observation data and the Fast Ocean- Atmosphere coupled Model 1.5 were used to investigate the triggering conditions under which the remote influence is formed between the positive sea surface temperature(SST) anomaly in the North Indian Ocean and the Anomalous Northwest Pacific anticyclone(ANWPA).Our research show that it is only when there is a contributory background wind field over the Indian Ocean,i.e.,when the Indian Summer Monsoon(ISM) reaches its peak,that the warmer SST anomaly in the North Indian Ocean incites significant easterly wind anomalies in the lower atmosphere of the Indo-West tropical Pacific.This then produces the remote influence on the ANWPA.Therefore,the SST anomaly in the North Indian Ocean might interfere with the prediction of the East Asia Summer Monsoon in the year of decaying El Ni o.Both the sustaining effect of local negative SST anomalies in the NWP,and the remote effect of positive SST anomalies in the North Indian Ocean on the ANWPA,should be considered in further research.
基金supported by the National Basic Research Program of China (Grant Nos.2012CB955600 and 2015CB954300)the National Natural Science Foundation of China (Grant Nos. 41106010 and 41476003)+1 种基金the State Key Laboratory of Tropical Oceanography, Chinese Academy of Sciences (Grant Nos. LTO1206 and LTOZZ1202)a China Meteorological Public Welfare Science Research Project (Grant No. GYHY201306027)
文摘Using 20 models of the Coupled Model Intercomparison Project Phase 5 （CMIP5）, the simulation of the Southwest Indian Ocean （SWIO） thermocline dome is evaluated and its role in shaping the Indian Ocean Basin （IOB） mode following E1 Nifio investigated. In most of the CMIP5 models, due to an easterly wind bias along the equator, the simulated SWIO thermocline is too deep, which could further influence the amplitude of the interannual IOB mode. A model with a shallow （deep） thermocline dome tends to simulate a strong （weak） IOB mode, including key attributes such as the SWIO SST warming, antisymmetric pattern during boreal spring, and second North Indian Ocean warming during boreal summer. Under global warming, the thermocline dome deepens with the easterly wind trend along the equator in most of the models. However, the IOB amplitude does not follow such a change of the SWIO thermocline among the models; rather, it follows future changes in both ENSO forcing and local convection feedback, suggesting a decreasing effect of the deepening SWIO thermocline dome on the change in the IOB mode in the future.
基金Supported by the National Key Research and Development Program of China(2018YFA0606301)National Natural Science Foundation of China(41875093,41705074,and 41530531).
文摘Sea surface temperature anomaly(SSTA)is a major signal for prediction of summer precipitation in East Asia.The relationship between SSTA in the tropical oceans and summer precipitation in East Asia has been documented in many studies.However,the relationship between SSTA and late summer(July–August)precipitation(JAP)over Northeast China(NEC)on the interannual timescale has received little attention.In this study,we examine the relationship between Indian Ocean Basin warming(IOBW)anomalies in spring and the JAP in NEC since the early1960 s.A significant positive correlation is found between the spring IOBW index and JAP over NEC.The positive spring IOBW anomaly is followed by an anomalous anticyclone from Northwest Pacific to the Korean Peninsula.This anomalous anticyclone favors a significantly strong and northward western Pacific subtropical high(WPSH),which facilitates anomalous southerly winds over NEC and the transport of more water vapor into this region.Further analysis indicates that the spring IOBW anomalies have important impacts on the vertical air motion in the tropics and subtropics during the summer.Significant anomalous upward(downward)motion covering Indonesia(Northwest Pacific to the southern Korean Peninsula)occurs when the IOBW is in its positive phase,which favors the northward movement of the WPSH in late summer and more precipitation over NEC in July–August.Modulation of the atmospheric circulation by this mechanism further influences the JAP over NEC.
基金supported by the National Key Program for Developing Basic Science(Grant Nos.2010CB428504&2012CB956002)National Natural Science Foundation of China(Grant Nos.40906005,41105059,41275069,GYHY201106017&GYHY201206038)the National Key Technologies R&D Program of China(Grant No.2009BAC51B01)
文摘Recent studies have found a connection between Indian Ocean Basin Warming and the anomalous Northwest Pacific Anticyclone(ANPWA) during El Ni?o decaying year.This study focuses on the necessary condition for this connection by using observation and numerical simulation.The seasonal transition of the Indian Ocean sea surface wind is critical to the climatic effect of Indian Ocean Basin Warming.When the South Asian Summer Monsoon reaches its peak,the background wind becomes desirable for basin warming,which then affects the climate in the Northwest Pacific.Via the Kelvin waves and Ekman divergence,the wind anomalies exist in the lower atmosphere east of the Indian Ocean warm Sea Surface Temperature(SST) anomalies,and intensify and sustain the ANWPA throughout the El Nio decaying summer.This impact plays an important role in the inter-annual variability of the East Asian Summer Monsoon.
