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Atmospheric and Oceanic Science Letters 2025年第1期18卷 6-11页

作者： Haoyu Zhou pang-chi hsu Lin Chen Yitian Qian Key Laboratory of Meteorological Disaster Ministry of Education/Joint International Research Laboratory of Climate and Environmental Change/Collaborative Innovation Center on Forecast and Evaluation of Meteorological DisastersNanjing University of Information Science and TechnologyNanjingChina

During the boreal summer,intraseasonal oscillations exhibit significant interannual variations in intensity over two key regions:the central-western equatorial Pacific(5°S-5°N,150°E-150°W)and the subtropical Northwestern Pacific(10°-20°N,130°E-175°W).The former is well-documented and considered to be influenced by the ENSO,while the latter has received comparatively less attention and is likely influenced by the Pacific Meridional Mode(PMM),as suggested by partial correlation analysis *** elucidate the physical processes responsible for the enhanced(weakened)intraseasonal convection over the subtropical northwestern Pacific during warm(cold)PMM years,the authors employed a moisture budget *** findings reveal that during warm PMM years,there is an increase in summer-mean moisture over the subtropical northwestern *** increase interacts with intensified vertical motion perturbations in the region,leading to greater vertical moisture advection in the lower troposphere and consequently resulting in convective *** a process is pivotal in amplifying intraseasonal convection *** observational findings were further verified by model experiments forced by PMM-like sea surface temperature patterns.

关键词： Boreal summer intraseasonal oscillation Interannual variability Pacific Meridional Mode Moisture budget analysis

Changes in Surface Energy Partitioning in china over the Past Three Decades

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Advances in Atmospheric Sciences 2017年第5期34卷 635-649页

作者： Yitian QIAN pang-chi hsu chi-Han CHENG Key Laboratory of Meteorological Disaster of Ministry of Education/Joint International Research Laboratory of Climate and Environment Change/Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters Nanjing University of lnformation Science and Technology Nanjing Jiangsu 210044 China Applied Hydrometeorological Research Institute Nanjing University of Information Science and Technology Nanjing Jiangsu 210044 China

Surface energy balance and the partitioning of sensible heat flux(SHF) and latent heat flux(LHF) play key roles in land–atmosphere feedback. However,the lack of long-term observations of surface energy fluxes,not to mention spatially extensive ones,limits our understanding of how the surface energy distribution has responded to a warming climate over recent decades(1979–2009) at the national scale in china. Using four state-of-the-art reanalysis products with long-term surface energy outputs,we identified robust changes in surface energy partitioning,defined by the Bowen ratio(BR = SHF/LHF),over different climate regimes in china. Over the past three decades,the net radiation showed an increasing trend over almost the whole of china. The increase in available radiative energy flux,however,was balanced by differential partitioning of surface turbulent fluxes,determined by local hydrological conditions. In semi-arid areas,such as Northeast china,the radiative energy was transferred largely into SHF. A severe deficiency in near-surface and soil moistures led to a significant decreasing trend in LHF. The combined effect of increased SHF and decreased LHF resulted in significant upward trends in the BR and surface warming over Northeast china. In contrast,in the wet monsoon regions,such as southern china,increased downward net radiation favored a rise in LHF rather than in SHF,leading to a significant decreasing trend in the BR. Meanwhile,the increased LHF partly cancelled out the surface warming. The warming trend in southern china was smaller than that in Northeast china. In addition to impacts on heat-related events,the changes in the BR also reflected recent cases of extreme drought in china. Our results indicate that information regarding the BR may be valuable for drought monitoring,especially in regions prone to such conditions.

关键词： surface energy partitioning Bowen ratio climate change long-term trend

Modulation of the Intraseasonal Variability of Pacific-Japan Pattern by ENSO

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Journal of Meteorological Research 2020年第3期34卷 546-558页

作者： Ying LI Fei LIU pang-chi hsu Earth System Modeling and Climate Dynamics Research Center Nanjing University of Information Science&TechnologyNanjing 210044

This study investigates how the El Nino-Southern Oscillation(ENSO)modulates the intraseasonal variability(ISV)of Pacific-Japan(PJ)teleconnection *** PJ index during boreal summer is constructed from the empirical orthogonal function(EOF)of the 850-hPa zonal wind(U850)*** periods of the PJ index are found during El Nino and La Nina *** ISV of the PJ pattern is significant during 10-25 days for both types of summers,it peaks on Days 30 and 60 in El Nino and La Nina summers *** El Nino summers,the 30-day ISV of PJ pattern is related to the northwestward propagating intraseasonal oscillation(ISO)over the western North Pacific(WNP),which is originated from the tropical Indian Ocean(IO).During La Nina summers,the 60-day ISV of PJ pattern is related to the northeastward propagating ISO from the tropical *** low-frequency ISV modes in both El Nino and La Nina summers are closely related to the boreal summer ISO(BSISO),and the high-frequency ISV modes over WNP are related to the quasi-biweekly *** underlying mechanisms for these different evolutions are also discussed.

关键词： Pacific–Japan(PJ)pattern El Nino–Southern Oscillation(ENSO) intraseasonal variability(ISV) intraseasonal oscillation(ISO) intraseasonal timescale low-frequency ISV mode boreal summer ISO

Madden–Julian Oscillation: Its Discovery, Dynamics, and Impact on East Asia

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Journal of Meteorological Research 2020年第1期34卷 20-42页

作者： Tim LI Jian LING pang-chi hsu Key Laboratory of Meteorological Disaster Ministry of Education(KLME)/Joint International Research Laboratory of Climate and Environmental Change(ILCEC)/Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters(CIC-FEMD)Nanjing University of Information Science&TechnologyNanjing 210044China International Pacific Research Center and Department of Atmospheric Sciences School of Ocean and Earth Science and TechnologyUniversity of Hawaii at ManoaHonoluluHI 96822USA State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China

In this review article,we pay primary attention to innovative works in the Madden–Julian Oscillation(MJO)field done by chinese *** historical aspect of discovery of the MJO and earlier studies of its dynamics by chinese scientists are first *** is followed by the description of recent advances in MJO propagation and initiation *** MJO eastward propagation,two types of the moisture mode theory are *** first one emphasizes the effect of zonal asymmetry of perturbation moisture in the atmospheric boundary layer and the second one emphasizes the zonal asymmetry of column integrated moisture static energy(MSE)*** mechanisms for MJO initiation over the western Indian Ocean include three distinctive processes:lower tropospheric moistening due to horizontal advection caused by preceding suppressed-phase MJO,midlatitude Rossby wave activity flux convergence in the upper troposphere originated from the Southern Hemisphere,and a delayed sea surface temperature feedback in association with a preceding opposite-phase *** impacts of MJO on low-frequency variability of precipitation and temperature and associated extreme events in East Asia are also discussed.

关键词： Madden–Julian Oscillation(MJO) propagation and initiation lower tropospheric moistening Rossby wave activity flux delayed sea surface temperature feedback

Influence of the Boreal Summer Intraseasonal Oscillation on Extreme Temperature Events in the Northern Hemisphere

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Journal of Meteorological Research 2018年第4期32卷 534-547页

作者： Yifei DIAO Tim LI pang-chi hsu Key Laboratory of Meteorological Disaster Ministry of Education/Joint International Research Laboratory of Climate and Environmental ChangeCollaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters Nanjing University of Information Science &Technology International Pacific Research Center and Department of Atmospheric Sciences School of Ocean and Earth Science and Technology University of Hawaii

The impact of the boreal summer intraseasonal oscillation （BSISO） on extreme hot and cool events was investig-ated, by analyzing the observed and reanalysis data for the period from 1983 to 2012. It is found that the frequency of the extreme events in middle and high latitudes is significantly modulated by the BSISO convection in the tropics, with a 3-9-day lag. During phases 1 and 2 when the BSISO positive rainfall anomaly is primarily located over a northwest-southeast oriented belt extending from India to Maritime Continent and a negative rainfall anomaly ap- pears in western North Pacific, the frequency of extreme hot events is 40% more than the frequency of non-extreme hot events. Most noticeable increase appears in midlatitude North Pacific （north of 40°N） and higher-latitude polar region. Two physical mechanisms are primarily responsible for the change of the extreme frequency. First, an upper-tropo-spheric Rossby wave train （due to the wave energy propagation） is generated in response to a negative heating anom-aly over tropical western North Pacific in phases 1 and 2. This wave train consists of a strong high pressure anomaly center northeast of Japan, a weak low pressure anomaly center over Alaska, and a strong high pressure anomaly cen-ter over the western coast of United States. Easterly anomalies to the south of the two strong midlatitude high pres-sure centers weaken the climatological subtropical jet along 40°N, which is accompanied by anomalous subsidence and warming in North Pacific north of 40°N. Second, an enhanced monsoonal heating over South Asia and East Asia sets up a transverse monsoonal overturning circulation, with large-scale ascending （descending） anomalies over trop-ical Indian （Pacific） Ocean. Both the processes favor more frequent extreme hot events in higher-latitude Northern Hemisphere. An anomalous atmospheric general circulation model is used to confirm the tropical heating effect.

关键词： boreal summer intraseasonal oscillation extreme hot events extreme cool events Rossby wave train monsoonal circulation

Drivers of elevation-dependent warming over the Tibetan Plateau

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Atmospheric and Oceanic Science Letters 2023年第2期16卷 16-21页

作者： Shuzhen Hu pang-chi hsu Key Laboratory of Meteorological Disaster Ministry of Education/Joint International Research Laboratory of Climate and Environment Change/Collaborative Innovation Center on Forecast and Evaluation of Meteorological DisastersNanjing University of Information Science&TechnologyNanjingChina

青藏高原(海拔≥3000 m地区)对全球气候变化的变暖响应是空间不均匀的,其增温幅度会随着海拔升高而增大,被称为海拔依赖性增温.青藏高原海拔依赖性增温具有季节依赖性,在冬季最为显著,达0.21℃km-1.在以往的研究中,众多因素被认为是青... 详细信息

青藏高原(海拔≥3000 m地区)对全球气候变化的变暖响应是空间不均匀的,其增温幅度会随着海拔升高而增大,被称为海拔依赖性增温.青藏高原海拔依赖性增温具有季节依赖性,在冬季最为显著,达0.21℃km-1.在以往的研究中,众多因素被认为是青藏高原海拔依赖性增温的可能驱动因素,但关于这些因素相对重要性的研究较少.基于多个数据集,本文应用辐射核(radiative kernel)技术方法定量诊断了近几十年(1979-2018年)冬季不同物理过程对青藏高原海拔依赖性增温的贡献.结果表明,与积雪变化相关的地表反照率反馈在其中起主导作用.观测数据分析显示,在过去40年的冬季,高海拔地区的积雪覆盖率显著减少,导致地表反射的短波辐射减少,从而促进了海拔依赖性增温.

关键词：海拔依赖性增温青藏高原辐射核地表反照率反馈

Sources of Subseasonal Prediction Skill for Heatwaves over the Yangtze River Basin Revealed from Three S2S Models

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Advances in Atmospheric Sciences 2020年第12期37卷 1435-1450页

作者： Jiehong XIE Jinhua YU Haishan CHEN pang-chi hsu Key Laboratory of Meteorological Disaster of Ministry of Education/Joint International Research Laboratory of Climate and Environment Change/Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters Nanjing University of Information Science&TechnologyNanjing 210044China

Based on the reforecast data(1999–2010)of three operational models[the china Meteorological Administration(CMA),the National Centers for Environmental Prediction of the U.S.(NCEP)and the European Centre for Medium-Range Weather Forecasts(ECMWF)]that participated in the Subseasonal to Seasonal Prediction(S2S)project,we identified the major sources of subseasonal prediction skill for heatwaves over the Yangtze River basin(YRB).The three models show limited prediction skills in terms of the fraction of correct predictions for heatwave days in summer;the Heidke Skill Score drops quickly after a 5-day forecast lead and falls down close to zero beyond the lead time of 15 *** superior skill of the ECMWF model in predicting the intensity and duration of the YRB heatwave is attributable to its fidelity in capturing the phase evolution and amplitude of high-pressure anomalies associated with the intraseasonal oscillation and the dryness of soil moisture induced by less precipitation via the land–atmosphere *** effects of 10–30-day and 30–90-day circulation prediction skills on heatwave predictions are comparable at shorter forecast leads(10 days),while the biases in 30–90-day circulation amplitude prediction show close connection with the degradation of heatwave prediction skill at longer forecast leads(>15–20 days).The biases of intraseasonal circulation anomalies further affect precipitation anomalies and thus land conditions,causing difficulty in capturing extremely hot days and their persistence in the S2S models.

关键词： subseasonal prediction heatwave Yangtze River Basin subseasonal-to-seasonal models

Distinctive MJO Activity during the Boreal Winter of the 2015/16 Super El Nino in Comparison with Other Super El Nino Events

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Advances in Atmospheric Sciences 2021年第4期38卷 555-568页

作者： Xuben LEI Wenjun ZHANG pang-chi hsu Chao LIU Key Laboratory of Meteorological Disaster Ministry of Education/Joint International Research Laboratory of Climate and Environmental Change/Collaborative Innovation Center on Forecast and Evaluation of Meteorological DisastersNanjing University of Information Science&TechnologyNanjing 210044China

Many previous studies have demonstrated that the boreal winters of super El Nino events are usually accompanied by severely suppressed Madden-Julian oscillation(MJO) activity over the western Pacific due to strong descending motion associated with a weakened Walker Circulation. However, the boreal winter of the 2015/16 super El Nino event is concurrent with enhanced MJO activity over the western Pacific despite its sea surface temperature anomaly(SSTA)magnitude over the Nino 3.4 region being comparable to the SSTA magnitudes of the two former super El Nino events(i.e.,1982/83 and 1997/98). This study suggests that the MJO enhanced over western Pacific during the 2015/16 super El Nino event is mainly related to its distinctive SSTA structure and associated background thermodynamic conditions. In comparison with the previous super El Nino events, the warming SSTA center of the 2015/16 super El Nino is located further westward, and a strong cold SSTA is not detected in the western Pacific. Accordingly, the low-level moisture and air temperature(as well as the moist static energy, MSE) tend to increase in the central-western Pacific. In contrast, the low-level moisture and MSE show negative anomalies over the western Pacific during the previous super El Nino *** the MJO-related horizontal wind anomalies contribute to the further westward warm SST-induced positive moisture and MSE anomalies over the western tropical Pacific in the boreal winter of 2015/16, stronger moisture convergence and MSE advection are generated over the western Pacific and lead to the enhancement of MJO convection.

关键词： super El Nino Madden-Julian oscillation moisture diagnosis

Changes in polar amplification in response to increasing warming in CMIP6

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Atmospheric and Oceanic Science Letters 2021年第3期14卷 54-59页

作者： Shenlin Cai pang-chi hsu Fei Liu Earth System Modeling and Climate Dynamics Research Center Nanjing University of Information Science and TechnologyNanjingChina School of Atmospheric Sciences Key Laboratory of Tropical Atmosphere-Ocean System Ministry of EducationSun Yat-Sen UniversityChina Southern Marine Science and Engineering Guangdong Laboratory ZhuhaiChina

The climate in polar regions has experienced an obvious warming amplification due to global *** this study,the changes in polar amplification are analyzed in response to feedback mechanisms(including Planck,lapse rate,cloud,water vapor,albedo feedback,CO_(2) radiative forcing,ocean heat uptake,and atmospheric heat transport)under three warming scenarios in CMIP6—namely,SSP1-2.6,SSP2-4.5,and *** results show that,by quantifying the warming contribution of different feedback mechanisms to surface air temperature with the“radiative kernel”method,Arctic amplification(AA)is stronger than Antarctic amplification(ANA),mostly resulting from the lapse rate feedback,followed by the albedo and Planck ***,ocean heat uptake causes stronger polar warming in winter than in *** winter,the lapse rate feedback causes a larger AA than *** intermodel spread for both AA and ANA decrease with increasing strength of global warming from SSP1-2.6 to SSP5-8.5,and the dominant mechanisms are the Planck,lapse rate,albedo,and ocean heat uptake *** findings help to enhance our understanding of polar regions’responses to different strengths of global warming.

关键词： Arctic amplification Antarctic amplification Radiative kernel CMIP6 Global warming

Disastrous Persistent Extreme Rainfall Events of the 2022 Pre-Flood Season in South china:Causes and Subseasonal Predictions

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Journal of Meteorological Research 2023年第4期37卷 469-485页

作者： Jiehong XIE pang-chi hsu Yamin HU Qiaomei LIN Mengxi YE Key Laboratory of Meteorological Disaster of Ministry of Education/Joint International Research Laboratory of Climate and Environment Change/Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters Nanjing University of Information Science&TechnologyNanjing 210000 Jieyang Meteorological Bureau China Meteorological AdministrationJieyang 522000 Guangdong Climate Center China Meteorological AdministrationGuangzhou 510000

Two persistent extreme rainfall events(PEREs) with record-breaking amounts of rainfall and long duration caused disastrous impact during the 2022 pre-flood season in South china. Atmospheric intraseasonal variability played a key role in triggering and maintaining both PEREs, but its major impact on each event was associated with different modes. For the first PERE(10-15 May;PERE1), the tropical and extratropical quasi-biweekly oscillations jointly contributed to the extreme rainfall intensity. In contrast, the long duration(6-21 June) of the heavy rainfall during the second PERE(PERE2) was closely related to prolonged convection and moisture transport anomalies induced mainly by the tropical 30-90-day variability. Subseasonal-to-seasonal predictions by the model of the ECMWF showed limited skill in relation to the rainfall intensity of PERE1 and PERE2 beyond 1–2 weeks. Further assessment suggested that the fidelity of the PERE predictions was linked to model skill in predicting the phase evolution and intensity of tropical and extratropical intraseasonal variabilities. Thus, efficient monitoring and accurate prediction of the various modes of atmospheric intraseasonal variability are fundamental to reducing the hazard associated with PEREs in South china.

关键词： persistent extreme rainfall event intraseasonal oscillation South china subseasonal-to-seasonal prediction