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Association between tropical convection and Boreal Wintertime Extratropical Circulation in 1982/83 and 1988/89

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Advances in Atmospheric Sciences 2003年第4期20卷 593-603页

作者： Ja-Yeon MOON Kyung-Ja HA Climate Research Laboratory Meteorological Research InstituteSeoul156-720KoreaDepartment of Atmospheric SciencesPusan National UniversityPusan609-735Korea

Boreal wintertime extratropical circulation is studied in relation to the tropical convection during the 1982/83 El Niño and 1988/89 La Niña. The anomaly structure of 1982/83 and 1988/89 over the extratropics reveals remarkably different features as the longitudinal tropical forcing region changes. The Rossby wave source (Positive) shows the largest maximum over East Asia in both years due to the persistent heating from the western Pacific warm pool area. However, the sink term shows contrasting features over the subtropics and extratropics between the two years. In the El Niño year, enhanced tropical convection over the eastern Pacific produces the Rossby wave sink at 10°N and shifted eastward over the North Pacific, while in the La Niña year, the sink area is shifted westward over the North Pacific. The contrasting features between the two events in mean-eddy interaction appears especially over the downstream area of the East Asian Jet. The extension (retraction) of the meanflow eastward (westward) to the east (west) of the dateline is related with the effect of the westward (eastward) E-vector and the strengthening (weakening) of the negative anomalies of the barotropic growth of kinetic energy. Hence, almost opposite characteristics between the two events can explain the close relationship of tropical convection and the extratropical internal variability.

关键词： tropical convection extratropical circulation rossby wave source mean-eddy interaction

Diurnal Variation of tropical convection during TOGA COARE IOP

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Advances in Atmospheric Sciences 2005年第5期22卷 685-702页

作者： Jae-Young BYON Gyu-Ho LIM School of Earth and Environmental Sciences Seoul National University Seoul South KoreaSchool of Earth and Environmental Sciences Seoul National University Seoul South Korea

Diurnal variation of tropical convection and kinematic and thermodynamic conditions was investigated for different large-scale environments of the convectively active and inactive periods by using satellite observations and surface measurements during the Intensive Observation Period （IOP） of the tropical Ocean Global Atmosphere/Coupled Ocean-Atmosphere Response Experiment （TOGA/COARE）. During the convectively active period, the features of nocturnal convection appear in vertical profiles of convergence, vertical velocity, heat source, and moisture sink. The specific humidity increases remarkably in the middle troposphere at dawn. On the other hand, the altitude of maximum convergence and that of the upward motion is lower during the convectively inactive period. The specific humidity peaks in the lower troposphere in the daytime and decreases in the middle troposphere. Spectral analyses of the time series of the infrared （IR） brightness temperature （TBB） and amounts of rainfall suggest multiscale temporal variation with a prominent diurnal cycle over land and oceanic regions such as the Intensive Flux Array （IFA） and the South Pacific Convergence Zone （SPCZ）. Over land, the daily maximum of deep convection associated with cloud top temperature less than 208 K appears at midnight due to the daytime radiative heating and the sea-land breeze. Over the ocean, convection usually tends to occur at dawn for the convectively active period while in the afternoon during the inactive period. Comparing the diurnal variation of convection with large-scale variables, the authors inferred that moisture in the middle troposphere contributes mostly to the development of nocturnal convection over the ocean during the convectively active period.

关键词： diurnal variation tropical convection rainfall large-scale environment

CLIMATIC ANALYSIS OF IMPACTS OF THE tropical convection IN WESTERN PACIFIC ON WESTERN PACIFIC SUBtropical HIGH'S SHORT-TERM SCALES DURING BOREAL SUMMER

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Acta meteorologica Sinica 2003年第3期17卷 307-320页

作者：吴秋霞倪允琪 Department of Atmospheric Sciences Nanjing University the Chinese Academy of Meteorological Sciences Chinese Academy of Meteorological Sciences

Based on the multi-year average NCEP/NCAR reanalysis data and NOAA's OLR data,the climatic characteristics of the tropical convection in tropical western Pacific and Indian Oceans as well as its relationship with western Pacific subtropical high (WPSH) is shown as follows:on short-term scales,the tropical convection that has significant influence on western Pacific high's latitudinal movement is located in the area of the South China Sea to the Philippines,which is the 2-day precursor prior to WPSH's latitudinal fluctuation,that is,WPSH is shifting to north 2 days after the tropical convection becomes more active,and vice ***,the tropical convection has less effect on WPSH's longitudinal movement.

关键词： western Pacific subtropical high (WPSH) tropical convection subseasonal scales

Interannual Meridional Displacement of the Upper-Tropospheric Westerly Jet over Western East Asia in Summer

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Advances in Atmospheric Sciences 2023年第7期40卷 1298-1308页

作者： Sining LING Riyu LU Hao LIU Yali YANG State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China College of Earth and Planetary Sciences University of Chinese Academy of SciencesBeijing 100049China Department of Atmospheric Sciences Yunnan UniversityKunming 650504China

The interannual meridional displacement of the upper-tropospheric westerly jet over the eastern portion of East Asia in summer has been well *** study,however,investigates the interannual meridional displacement of the westerly jet over the western portion of East Asia in summer,which is distinct from its eastern *** results show that the meridional displacement of the western East Asian jet shows a clear asymmetric feature;that is,there are remarkable differences between the southward and northward displacement of the *** southward displacement of the jet corresponds to suppressed convection in the tropical western North Pacific and Maritime Continent and enhanced convection in the equatorial Pacific,which can be explained by the warmer sea surfaces found in the northern Indian Ocean and equatorial eastern *** tropical anomalies somewhat resemble those associated with the eastern East Asian jet ***,the northward displacement of the western East Asian jet does not correspond to significant convection and SST anomalies in the entire tropics;instead,the northward displacement of the jet corresponds well to the positive phase of the Arctic ***,the meridional displacement of the western jet has asymmetric impacts on rainfall and surface air temperatures in East *** the western jet shifts northward,more precipitation is found over South China and Northeast China,and higher temperatures appear in northern *** contrast,when the jet shifts southward,more precipitation appears over the East Asian rainy belt,including the Yangtze River valley,South Korea,and southern and central Japan and warmer temperatures are found South and Southeast Asia.

关键词： westerly jet East Asia tropical convection Arctic Oscillation summer

tropical Convective Activities Related to Summer Rainfall Anomaly in China

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Advances in Atmospheric Sciences 2000年第1期17卷 121-128页

作者：郭品文田红刘宣飞 Department of Atmospheric Sciences Nanjing Institute of Meteorology Nanjing Anhui Meteorological Center Hefei

The paper presents the SVD-revealed relation of the tropical convection anomaly patterns to the summer rainfall counterparts of China, indicating that a) the ENSO-associated tropical con-vection anomaly is highly advantageous but the corresponding rainfall anomaly can only account for 10.3% of total variance, the rainfall anomaly related to tropical monsoon variation with the northern South China Sea as the center of convection abnormality for 18.8% and to the variation inside the tropical monsoon for 11.2%; b) the ENSO-related summer precipitation anomaly dis-plays a pattern of excessive rainfall in the south and deficit in the north, the anomaly relative to the tropical monsoon variation a pattern of more precipitation in the Yangtze River valleys and less in North, Northeast and South China, and that in relation to the variation within the tropical mon-soon a pattern of two rainbands, one in the Yangtze River valleys and the other in North China. Key words tropical convection - Singular value decomposition (SVD) - Rainfall pattern (1)This work is supported by the National Natural Sciences Foundation of China under Grant No. 49775265.

关键词： tropical convection Singular value decomposition (SVD) Rainfall pattern

The Circum-Pacific Teleconnection Pattern in Meridional Wind in the High Troposphere

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Advances in Atmospheric Sciences 2005年第3期22卷 463-466页

作者：王会军 Nansen-Zhu International Research CenterInstitute of Atmospheric Physics Chinese Academy of SciencesBeijing 100029

The Circum-Pacific Teleconnection Pattern (CPTP) is revealed in the meridional wind in the high troposphere via an emprirical orthogonal function (EOF) and correlation analysis on NCEP/NCAR re-analysis data. The CPTP is found to be composed of the North Pacific-North American teleconnection pattern (PNA), the South Pacific-South American teleconnection pattern (PSA), and the teleconnection patterns over the tropical western Pacific and the tropical eastern Pacific (or, Central America, or, tropical Atlantic). There is substantial interannual variability of the CPTP and a typical CPTP can be detected in some years. It is speculated that the zonal wind anomalies over the equatorial region in the western and eastern sides of the Pacific may play a role in linking the two hemispheres. The anomalous convection activities in the Tropics are plausible triggering factors for the zonal wind anomalies that are responsible for the composition of the CPTP.

关键词： CPTP PNA PSA zonal wind anomaly tropical convection

The Combined Effects of the tropical and Extratropical Quasi-biweekly Oscillations on the Record-setting Mei-yu Rainfall in the Summer of 2020

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Advances in Atmospheric Sciences 2023年第4期40卷 663-681,I0002-I0014页

作者： Zhen HUANG Shuanglin LI Jianying LI Chao ZHANG Department of Atmospheric Science/Centre for Severe Weather and Climate and Hydro-geological Hazards China University of GeosciencesWuhan 430074China China Climate Change Research Center Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China State Key Laboratory of Severe Weather(LASW) Chinese Academy of Meteorological SciencesBeijing 100081China

During June-July 2020,the strongest recorded mei-yu rainfall occurred in the middle and lower reaches of the Yangtze *** rainfall processes exhibited an obvious quasi-biweekly(biweekly in brief)variability,and there are altogether five *** is found that the biweekly rainfall cycle mainly arises from the collaborative effects of biweekly variabilities from both the tropics and *** for the tropics,the biweekly meridional march and retreat of the western Pacific subtropical high(WPSH)is particularly *** for the extratropics,geopotential height anomalies near Lake Baikal are *** former is attributed to the intensified biweekly activity of the southwest-northeast oriented EastAsian Pacific wave train(EAP)originating from the tropical western Pacific,while the latter is associated with the biweekly activities of the eastward propagating Eurasia mid-high latitudinal wave train and the westward propagating North Pacific wave *** the biweekly activities of these wave trains intensified is further diagnosed from the perspective of thermodynamical forcing and also from the modulation of interannual background on intraseasonal *** is found that the strongest recorded convection anchoring over the tropical western Indian Ocean(IO)triggers anomalous descent over the tropical western Pacific,which modulates the biweekly activity of the ***,the anomalous diabatic heating over the IO causes changes of the meridional thermodynamic contrast across the IO to the high latitudes,which modulates the extratropical wave trains.A further diagnosis of barotropic kinetic energy conversion suggests that the active occurrence of two extratropical biweekly wave trains is attributed to the increased efficiency of energy conversion from basic *** westward propagation of the extratropical North Pacific wave train is attributed to the weakened and northshifted upper-level westerly,which is caused by the SST warmth near the Kuroshio

关键词： strongest recorded mei-yu rainfall in summer 2020 quasi-biweekly variability tropical convection westward propagation of the extratropical North Pacific wave train SSTA in the North Pacific

Investigating the Effects of Madden-Julian Oscillation on Climate Elements of Iran (1980-2020)

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Journal of Atmospheric Science Research 2023年第2期6卷 21-32页

作者： Kourosh Mohammadpour Zahra Hejazizadeh Hooshang Ghaemi Mohammad Salighe Department of Natural Geography Kharazmi UniversityTehran15447-33111Iran Tehran Institute of Meteorology and Atmospheric Sciences Tehran15447-33111Iran

The Madden-Julian Oscillation is one of the large-scale climate change patterns in the maritime tropics,with sub-seasonal time periods of 30 to 60 days affecting tropical and subtropical *** phenomenon can cause changes in various quantities of the atmosphere and ocean,such as pressure,sea surface temperature,and the rate of evaporation from the ocean surface in tropical *** this research,the effects of Madden-Julian fluctuation on the weather elements of Iran have been investigated with the aim of knowing the effects of different phases in order to improve the quality of forecasts and benefits in territorial *** first,the daily rainfall data of 1980-2020 were received from the National Meteorological Organization and quality *** the Wheeler and Hendon method,the two main components RMM1 and RMM2 were analyzed,based on which the amplitude of the above two components is considered as the main indicator of the intensity and weakness of this *** index is based on the experimental orthogonal functions of the meteorological fields,including the average wind levels of 850 and 200 hectopascals and outgoing long wave radiation(OLR)between the latitudes of 20 degrees south and 20 degrees *** clustering of the 7-day sequence with a component above 1 was used as the basis for clustering all eight phases,and by calculating the abnormality of each phase compared to its long term in the DJF time frame,the zoning of each phase was produced *** the end,phases 1,2,7,8 were concluded as effective phases in Iran’s rainfall and phases 3,4,5,6 as suppressive phases of Iran’s rainfall.

关键词： Madden-Julian oscillation tropical convection precipitation Long-wave radiation Sub-seasonal oscillation

DIAGNOSES OF THE SEVERE DROUGHT OVER YUNNAN AREA IN THE EARLY SUMMER OF 2005

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Journal of tropical Meteorology 2007年第1期13卷 93-96页

作者：刘瑜赵尔旭杨淑群彭贵芬 Climate Center of Yunnan Meteorological Science and Technology Services Center of Yunnan Climate Center of Sichuan Yunnan Meteorological Observatory

High temperature and drought occurred in Yunnan province during the late spring and early summer in 2005, which was the most severe event in this region since 1950’s. Based on the observational data and relevant diagnoses, this extreme weather event was studied and discussed. The results show that the occurrence of this event could be due to the following observational facts that happened in 2005. (1) The seasonal adjustment of middle-high-leveled atmospheric circulation was delayed. (2) The cold air activity center was deviated north. (3) The onset of summer monsoon over South China Sea was delayed. (4) The tropical convection activity was much weaker than usual. (5) The subtropical high over the western Pacific was located southwestwards and relatively strong.

关键词： Yunnan high temperature and drought summer monsoon of South China Sea subtropical high tropical convection