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| 1 | Tibetan Plateau climate dynamics: recent research progress and outlook显示文摘This paper reviews progress in the study of Tibetan Plateau(TP) climate dynamics over the past decade.Several theoretical frameworks, including thermal adaptation and the TP sensible heat(SH) driving air-pump, have been developed to identify the mechanisms responsible for the circulation anomaly produced by thermal forcing of the TP. Numerical simulations demonstrate that the thermal efects of large-scale orography, including the Tibetan and Iranian Plateaus(TIP), are crucial for the formation of the East Asian and South Asian summer monsoons(SASM) because the surface SH of the TIP is the major driver of the water vapor transport required for the genesis of the north branch of the SASM. he large-scale orography of the TP afects the Asian climate through thermal forcing in spring and summer, and mechanical forcing in winter. he TP forcing can also inluence the Asian summer monsoon(ASM) onset over the Bay of Bengal(BOB) by enhancing the BOB warm pool at the surface and by modulating the South Asian High(SAH) in the upper troposphere. On intra-seasonal timescales, the TP thermal forcing signiicantly modulates spring rainfall in southern China and generates the biweekly oscillation of the SAH in summer. Despite climate warming, the atmospheric heat source over the TP, particularly the spring SH,exhibits a clear weakening trend from the 1980 s to 2000 s. his weakening of the spring SH contributed to the anomalous ‘dry in the north' and ‘wet in the south' rainfall patern observed over East China. Also discussed are challenges to further understanding the mechanism of TP forcing on the multi-scale variability of the ASM. | Guoxiong Wu Anmin Duan Yimin Liu Jiangyu Mao Rongcai Ren Qing Bao Bian He Boqi Liu Wenting Hu | 2015 | National Science Review2015，2，1： | 51 |
| 2 | Diurnal variations of summer precipitation over the Asian monsoon region as revealed by TRMM satellite data显示文摘Climatological characteristics of diurnal variations in summer precipitation over the Asian monsoon region are comprehensively investigated based on the Tropical Rainfall Measuring Mission(TRMM) satellite data during 1998-2008.The topographic influence on the diurnal variations and phase propagations of maximum precipitation are identified according to spatiotemporal distributions of the amplitude and peak time of the diurnal precipitation.The amplitude and phase of diurnal precipitation show a distinct geographical pattern.Significant diurnal variations occur over most of continental and coastal areas including the Maritime Continent,with the relative amplitude exceeding 40%,indicating that the precipitation peak is 1.4 times the 24-h mean.Over the landside coasts such as southeastern China and Indochina Peninsula,the relative amplitude is even greater than 100%.Although the diurnal variations of summer precipitation over the continental areas are characterized by an afternoon peak(1500-1800 Local Solar Time(LST)),over the central Indochina Peninsula and central and southern Indian Peninsula the diurnal phase is delayed to after 2100 LST,suggesting the diurnal behaviors over these areas different from the general continental areas.The weak diurnal variations with relative amplitudes less than 40% exist mainly over oceanic areas in the western Pacific and most of Indian Ocean,with the rainfall peak mainly occurring from midnight to early morning(0000-0600 LST),indicating a typical oceanic regime characterized by an early morning peak.However,apparent exceptions occur over the South China Sea(SCS),Bay of Bengal(BOB),and eastern Arabian Sea,with the rainfall peak occurring in daytime(0900-1500 LST).Prominent meridional propagations of the diurnal phase exist in South Asia and East Asia.Along the eastern Indian Peninsula,there is not only the southward phase propagation with the peak occurring around 25°N but also the northward phase propagation with the peak beginning with the southernmost continent,and both reach the central Indian continent to finish.Along the same longitudes where southern China and Kalimantan are located,the diurnal phase of the former propagates from the oceanic area(northern SCS) toward the inland continent,while the phase of the latter propagates from the land area toward the outside sea,showing a landward or seaward coastal diurnal regime.A distinct zonal propagation of the diurnal phase is observed over the BOB oceanic area.The maximum precipitation zone originates from the land-sea boundary of the eastern coast of the Indian peninsula at around 0300 LST,and then propagates eastward with increasing time to reach the eastern coast of the BOB on 1800 LST,finally migrates into the Indochina continent on about 2100 LST. | JiangYu Mao GuoXiong Wu | 2012 | Science China Earth Sciences2012，55，4： | 20 |
| 3 | Vortex genesis over the Bay of Bengal in spring and its role in the onset of the Asian Summer Monsoon显示文摘Physical processes associated with onset of the 1998 Asian summer monsoon were examined in detail using multi-source datasets. We demonstrated that strong ocean-atmosphere-land interaction in the northern Indian Ocean and tropical Asian area during spring is a fundamental factor that induces the genesis and development of a monsoon onset vortex over the Bay of Bengal (BOB), with the vortex in turn triggering onset of the Asian summer monsoon. In spring, strong surface sensible heating over India and the Indochina Peninsula is transferred to the atmosphere, forming prominent in situ cyclonic circulation, with anticyclonic circulations over the Arabian Sea and northern BOB where the ocean receives abundant solar radiation. The corresponding surface winds along the North Indian Ocean coastal areas cause the ocean to produce the in situ offshore currents and upwelling, resulting in sea surface temperature (SST) cooling. With precipitation on the Indochina Peninsula increasing from late April to early May, the offshore current disappears in the eastern BOB or develops into an onshore current, leading to SST increasing. A southwest-northeast oriented spring BOB warm pool with SST >31°C forms in a band from the southeastern Arabian Sea to the eastern BOB. In early May, the Somali cross-equatorial flow forms due to the meridional SST gradient between the two hemispheres, and surface sensible heat over the African land surface. The Somali flow overlaps in phase with the anticyclone over the northern Arabian Sea in the course of its inertial fluctuation along the equator. The convergent cold northerlies on the eastern side of the anticyclone cause the westerly in the inertial trough to increase rapidly, so that enhanced sensible heat is released from the sea surface into the atmosphere. The cyclonic vorticity forced by such sensible heating is superimposed on the inertial trough, leading to its further increase in vorticity strength. Since atmospheric inertial motion is destroyed, the flow deviates from the inertial track in an intensified cyclonic curvature, and then turns northward toward the warm pool in the northern BOB. It therefore converges with the easterly flow on the south side of the anticyclone over the northern BOB, forming a cyclonic circulation center east of Sri Lanka. Co-located with the cyclonic circulation is a generation of atmospheric potential energy, due to lower tropospheric heating by the warm ocean. Eventually the BOB monsoon onset vortex (MOV) is generated east of Sri Lanka. As the MOV migrates northward to the warm pool it develops quickly such that the zonal oriented subtropical high is split over the eastern BOB. Thus, the tropical southwesterly on the southern and eastern sides of the MOV merges into the subtropical westerly in the north, leading to active convection over the eastern BOB and western Indochina Peninsula and onset of the Asian summer monsoon. | WU GuoXiong GUAN Yue WANG TongMei LIU YiMin YAN JingHui MAO JiangYu | 2011 | Science China Earth Sciences2011，54，1： | 16 |
| 4 | Change in the tilting of the ridgeline surface of the subtropical anticyclone and the predictability of the onset of the Asian summer monsoon显示文摘The NCEP/NCAR reanalysis data are used tostudy the relationships among the change in the tilting of theridgeline surface of the subtropical anticyclone, the estab-lishment of the so-called 'seasonal transition axis (STA)' andthe onset of the Asian summer monsoon. It is shown that themonsoon onset is characterized by the overturning of themeridional temperature gradient (MTG) in the vicinity of theridgeline surface. A MTG index is then constructed to inves-tigate the predictability of the Asian summer monsoon onsetconceptually. Data diagnoses show that if the initial MTG isknown and the meridional gradient across the ridgeline sur-face of the local temperature tendency can be estimated, alate or early onset of the summer monsoon can be qualita-tively predicted in advance. | MAO Jiangyu, DUAN Anmin, LIU Yimin WU Guoxiong State Key Laboratory of Numerical Modeling for Almospheric Sciences and Geophysical Fluid Dynamics (LASG), Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China | 2003 | Chinese Science Bulletin2003，48，S2： | 6 |
| 5 | 导致2018年夏季东北亚极端高温的中高纬环流异常分析(英文)显示文摘2018年东北亚经历了过去40年以来最热的夏季(7–8月),其夏季平均的地表气温异常(1.2°C)几乎达到该地区气温年际标准差的2倍。本文指出此次极端高温与东北亚上空深厚的位势高度正异常有关,在分析时段内(1979–2018年)其强度在2018年最强。回归分析结果表明,北欧和里海的高层环流异常都可以通过激发下游波列对东北亚上空的环流产生重要影响。特别的是,2018年夏季北欧和里海的位势高度均显著增强,且均遭遇了极端高温的侵袭,位势高度正异常和高温异常也在分析时段内达到最强,因而通过波列共同促成了东北亚极端的位势高度正异常和高温。本文研究结果说明,为全面了解东北亚地区的温度变率,对中高纬的两种遥相关型特别是其波源的理解至关重要,值得进一步研究。 | XU Ke LU Riyu MAO Jiangyu CHEN Ruidan | 2019 | Atmospheric and Oceanic Science Letters2019，12，4： | 6 |
| 6 | A Comparative Study on the Dominant Factors Responsible for the Weaker-than-expected El Ni?o Event in 2014显示文摘Anomalous warming occurred in the equatorial central-eastern Pacific in early May 2014,attracting much attention to the possible occurrence of an extreme El Ni?o event that year because of its similarity to the situation in early 1997. However,the subsequent variation in sea surface temperature anomalies(SSTAs) during summer 2014 in the tropical Pacific was evidently different to that in 1997,but somewhat similar to the situation of the 1990 aborted El Ni?o event. Based on NCEP(National Centers for Environmental Prediction) oceanic and atmospheric reanalysis data,the physical processes responsible for the strength of El Ni?o events are examined by comparing the dominant factors in 2014 in terms of the preceding instability of the coupled ocean–atmosphere system and westerly wind bursts(WWBs) with those in 1997 and 1990,separately. Although the unstable ocean–atmosphere system formed over the tropical Pacific in the preceding winter of 2014,the strength of the preceding instability was relatively weak. Weak oceanic eastward-propagating downwelling Kelvin waves were forced by the weak WWBs over the equatorial western Pacific in March 2014,as in February 1990. The consequent positive upper-oceanic heat content anomalies in the spring of 2014 induced only weak positive SSTAs in the central-eastern Pacific–unfavorable for the subsequent generation of summertime WWB sequences. Moreover,the equatorial western Pacific was not cooled,indicating the absence of positive Bjerknes feedback in early summer 2014. Therefore,the development of El Ni?o was suspended in summer 2014. | LI Jianying LIU Boqi LI Jiandong MAO Jiangyu | 2015 | Advances in Atmospheric Sciences2015，32，10： | 3 |
| 7 | The 30–60-day Intraseasonal Variability of Sea Surface Temperature in the South China Sea during May–September显示文摘This study investigates the structure and propagation of intraseasonal sea surface temperature(SST) variability in the South China Sea(SCS) on the 30–60-day timescale during boreal summer(May–September). TRMM-based SST, GODAS oceanic reanalysis and ERA-Interim atmospheric reanalysis datasets from 1998 to 2013 are used to examine quantitatively the atmospheric thermodynamic and oceanic dynamic mechanisms responsible for its formation. Power spectra show that the 30–60-day SST variability is predominant, accounting for 60% of the variance of the 10–90-day variability over most of the SCS. Composite analyses demonstrate that the 30–60-day SST variability is characterized by the alternate occurrence of basin-wide positive and negative SST anomalies in the SCS, with positive(negative) SST anomalies accompanied by anomalous northeasterlies(southwesterlies). The transition and expansion of SST anomalies are driven by the monsoonal trough–ridge seesaw pattern that migrates northward from the equator to the northern SCS. Quantitative diagnosis of the composite mixed-layer heat budgets shows that, within a strong 30–60-day cycle, the atmospheric thermal forcing is indeed a dominant factor, with the mixed-layer net heat flux(MNHF) contributing around 60% of the total SST tendency, while vertical entrainment contributes more than 30%. However, the entrainment-induced SST tendency is sometimes as large as the MNHF-induced component, implying that ocean processes are sometimes as important as surface fluxes in generating the30–60-day SST variability in the SCS. | Jiangyu MAO Ming WANG | 2018 | Advances in Atmospheric Sciences2018，35，5： | 3 |
| 8 | Decadal Changes in Interannual Dependence of the Bay of Bengal Summer Monsoon Onset on ENSO Modulated by the Pacific Decadal Oscillation显示文摘Interannual variations of the Bay of Bengal summer monsoon (BOBSM) onset in association with El Ni-o-Southern Oscillation (ENSO) are reexamined using NCEP1, JRA-55 and ERA20C atmospheric and Hadley sea surface temperature (SST) reanalysis datasets over the period 1900-2017. Decadal changes exist in the dependence of the BOBSM onset on ENSO, varying with the Pacific Decadal Oscillation (PDO). A higher correlation between the BOBSM onset and ENSO arises during the warm PDO epochs, with distinct late (early) onsets following El Ni-o (La Ni-a) events. In contrast, less significant correlations occur during the cold PDO epochs. The mechanism for the PDO modulating the ENSO-BOBSM onset relationship is through the variations in SST anomaly (SSTA) patterns. During the warm PDO epochs, the superimpositions of the PDO-related and ENSO-related SSTAs lead to the SSTA distribution of an El Ni-o (La Ni-a) event exhibiting significant positive (negative) SSTAs over the tropical central-eastern Pacific and Indian Ocean along with negative (positive) SSTAs, especially over the tropical western Pacific (TWP), forming a strong zonal interoceanic SSTA gradient between the TWP and tropical Indian Ocean. Significant anomalous lower tropospheric easterlies (westerlies) together with upper-tropospheric westerlies (easterlies) are thus induced over the BOB, favoring an abnormally late (early) BOBSM onset. During the cold PDO epochs, however, the superimpositions of PDO-related SSTAs with El Ni-o-related (La Ni-a-related) SSTAs lead to insignificant SSTAs over the TWP and a weak zonal SSTA gradient, without distinct circulation anomalies over the BOB favoring early or late BOBSM onsets. | Xiaofei WU Jiangyu MAO | 2019 | Advances in Atmospheric Sciences2019，36，12： | 2 |
| 9 | PV Perspective of Impacts on Downstream Extreme Rainfall Event of a Tibetan Plateau Vortex Collaborating with a Southwest China Vortex显示文摘An extreme rainfall event occurred over the middle and lower reaches of the Yangtze Basin(MLY)during the end of June 2016,which was attributable to a Tibetan Plateau(TP)Vortex(TPV)in conjunction with a Southwest China Vortex(SWCV).The physical mechanism for this event was investigated from Potential Vorticity(PV)and omega perspectives based on MERRA-2 reanalysis data.The cyclogenesis of the TPV over the northwestern TP along with the lower-tropospheric SWCV was found to involve a midtropospheric large-scale flow reconfiguration across western and eastern China with the formation of a high-amplitude Rossby wave.Subsequently,the eastward-moving TPV coalesced vertically with the SWCV over the eastern Sichuan Basin due to the positive vertical gradient of the TPV-related PV advection,leading the lower-tropospheric jet associated with moisture transport to intensify greatly and converge over the downstream MLY.The merged TPV−SWCV specially facilitated the upper-tropospheric isentropic-gliding ascending motion over the MLY.With the TPV-embedded mid-tropospheric trough migrating continuously eastward,the almost stagnant SWCV was re-separated from the overlying TPV,forming a more eastward-tilted high-PV configuration to trigger stronger ascending motion including isentropic-gliding,isentropic-displacement,and diabatic heating-related ascending components over the MLY.This led to more intense rainfall.Quantitative PV diagnoses demonstrate that both the coalescence and subsequent re-separation processes of the TPV with the SWCV were largely dominated by horizontal PV advection and PV generation due to vertically nonuniform diabatic heating,as well as the feedback of condensation latent heating on the isentropic-displacement vertical velocity. | Guanshun ZHANG Jiangyu MAO Yimin LIU Guoxiong WU | 2021 | Advances in Atmospheric Sciences2021，38，11： | 2 |
| 10 | A Timescale Decomposed Threshold Regression Downscaling Approach to Forecasting South China Early Summer Rainfall显示文摘A timescale decomposed threshold regression(TSDTR) downscaling approach to forecasting South China early summer rainfall(SCESR) is described by using long-term observed station rainfall data and NOAA ERSST data. It makes use of two distinct regression downscaling models corresponding to the interannual and interdecadal rainfall variability of SCESR.The two models are developed based on the partial least squares(PLS) regression technique, linking SCESR to SST modes in preceding months on both interannual and interdecadal timescales. Specifically, using the datasets in the calibration period 1915–84, the variability of SCESR and SST are decomposed into interannual and interdecadal components. On the interannual timescale, a threshold PLS regression model is fitted to interannual components of SCESR and March SST patterns by taking account of the modulation of negative and positive phases of the Pacific Decadal Oscillation(PDO). On the interdecadal timescale, a standard PLS regression model is fitted to the relationship between SCESR and preceding November SST patterns. The total rainfall prediction is obtained by the sum of the outputs from both the interannual and interdecadal models. Results show that the TSDTR downscaling approach achieves reasonable skill in predicting the observed rainfall in the validation period 1985–2006, compared to other simpler approaches. This study suggests that the TSDTR approach,considering different interannual SCESR-SST relationships under the modulation of PDO phases, as well as the interdecadal variability of SCESR associated with SST patterns, may provide a new perspective to improve climate predictions. | Linye SONG Wansuo DUAN Yun LI Jiangyu MAO | 2016 | Advances in Atmospheric Sciences2016，33，9： | 2 |
| 11 | Synergistic Effect of the Planetary-scale Disturbance, Typhoon and Meso-β-scale Convective Vortex on the Extremely Intense Rainstorm on 20 July 2021 in Zhengzhou显示文摘On 20 July 2021,northern Henan Province in China experienced catastrophic flooding as a result of an extremely intense rainstorm,with a record-breaking hourly rainfall of 201.9 mm during 0800–0900 UTC and daily accumulated rainfall in Zhengzhou City exceeding 600 mm(“Zhengzhou 7.20 rainstorm”for short).The multi-scale dynamical and thermodynamical mechanisms for this rainstorm are investigated based on station-observed and ERA-5 reanalysis datasets.The backward trajectory tracking shows that the warm,moist air from the northwestern Pacific was mainly transported toward Henan Province by confluent southeasterlies on the northern side of a strong typhoon In-Fa(2021),with the convergent southerlies associated with a weaker typhoon Cempaka(2021)concurrently transporting moisture northward from South China Sea,supporting the rainstorm.In the upper troposphere,two equatorward-intruding potential vorticity(PV)streamers within the planetary-scale wave train were located over northern Henan Province,forming significant divergent flow aloft to induce stronger ascending motion locally.Moreover,the converged moist air was also blocked by the mountains in western Henan Province and forced to rise so that a deep meso-β-scale convective vortex(MβCV)was induced over the west of Zhengzhou City.The PV budget analyses demonstrate that the MβCV development was attributed to the positive feedback between the rainfall-related diabatic heating and high-PV under the strong upward PV advection during the Zhengzhou 7.20 rainstorm.Importantly,the MβCV was forced by upper-level larger-scale westerlies becoming eastward-sloping,which allowed the mixtures of abundant raindrops and hydrometeors to ascend slantwise and accumulate just over Zhengzhou City,resulting in the record-breaking hourly rainfall locally. | Guanshun ZHANG Jiangyu MAO Wei HUA Xiaofei WU Ruizao SUN Ziyu YAN Yimin LIU Guoxiong WU | 2023 | Advances in Atmospheric Sciences2023，40，3： | 1 |
| 12 | Different seal ing behaviors in daily temperature records over China 显示文摘 | YUAN Naiming FU Zuntao MAO Jiangyu | 2010 | Physica A2010，389，19： | 1 |
| 13 | Intraseasonal variability of the South China Sea summer monsoon显示文摘 | MAO Jiangyu CHAN J C L | 2005 | Journal of Climate2005，18，13： | 1 |
| 14 | Intraseasonal Variability of the South China Sea Summer Monsoon显示文摘 | JIANGYU MAO CHAN J C L | 2005 | J of Climate2005，，18： | 1 |
| 15 | 冬季中国东北地区天气尺度位涡下侵及其对地面气温的影响(英文)显示文摘本文将每天一定区域内有平流层位涡向下侵入到对流层现象的格点总数定义为天气尺度区域位涡下侵(RPVI)指数,由此建立了1979至2016年冬季中国东北地区RPVI指数的年际变化序列。合成分析表明,在高(低)RPVI指数年,平流层位涡正(负)异常于90°–110°E区域向下侵入至对流层300 hPa附近,因而在对流层低层强迫出异常气旋(反气旋)。近地层异常气旋(反气旋)西侧的北(南)风导致东北地区地面气温异常至少低于(高于)-0.9°C(0.9°C)。 | ZHU Tingting MAO Jiangyu | 2019 | Atmospheric and Oceanic Science Letters2019，12，4： | 1 |
| 16 | 20-50-day oscillation of summer Yangtze rainfall in response to intraseasonal variations in the subtropical high over the western North Pacific and South Chi- na Sea 显示文摘 | Mao Jiangyu Zhang Sun Wu Guoxiong | 2010 | Climate Dynamics2010，34，： | 1 |
| 17 | Interannual Relationship between Summer North Atlantic Oscillation and Subsequent November Precipitation Anomalies over Yunnan in Southwest China显示文摘The summer North Atlantic Oscillation(SNAO)strongly affects the climate variability over Europe and downstream East Asia similar to its winter counterpart.This study thus investigates the interannual relationship between SNAO and the subsequent autumn precipitation anomalies over Yunnan,Southwest China and related physical mechanisms based on reanalysis data during 1958–2020.The results show that the interannual variations in SNAO exhibit a significant positive correlation with anomalies of Yunnan precipitation in November.Composite analyses demonstrate that for the positive SNAO phase,the positive sea surface temperature anomalies(SSTAs)in midlatitude North Atlantic as part of a tripole SSTA tend to weaken from summer to November through changes in surface heat fluxes.In turn,the predominately negative SSTA in tropical North Atlantic that persists into November induces an anomalous cyclone at midlatitudes,which triggers two middle–upper tropospheric wave trains propagating from midlatitude North Atlantic to Yunnan.The subtropical wave train propagates eastward along the subtropical westerly jet,and the mid–high latitude wave train follows the great circle path across Scandinavia and central Asia to the Tibetan Plateau.Both wave trains favor development of an anomalous cyclone over the southern Tibetan Plateau.The upper-tropospheric divergent condition on the southeastern side of the anomalous cyclone is dynamically conducive to locally ascending motion over Yunnan,thus producing above-normal precipitation.The opposite situation occurs in the negative SNAO phase.A coupled model reproduces well the wave train propagation and thereby confirms the positive relationship between SNAO and Yunnan precipitation in November. | Shabin HAO Jiandong LI Jiangyu MAO | 2022 | Journal of Meteorological Research2022，36，5： | 0 |
| 18 | The Tibetan Plateau bridge:Influence of remote teleconnections from extratropical and tropical forcings on climate anomalies显示文摘本文回顾了青藏高原桥梁作用方面的最新研究进展,涉及北大西洋气候异常对春,夏亚洲季风和厄尔尼诺-南方涛动(ENSO)事件的遥相关影响,热带海洋异常和中国东部极端气候异常之间的联系以及华南春雨的季节内变化等.介绍了年际时间尺度上,冬-春季北大西洋海表温度强迫如何影响南亚季风的季节性转变以及随后ENSO事件的触发.5月份青藏高原上空显著的负感热斜压结构,为北大西洋影响亚洲季风和ENSO提供了桥梁效应,夏季北大西洋涛动与华东夏季降水变化显著相关,高原潜热在这一关系中起着桥梁作用.另一方面,这种高原桥梁效应也存在于从热带海洋异常到东亚夏季极端降水事件的连接中,以及从中纬度波列到华南春雨准双周振荡的联系中. | Yimin Liu Wei Yu Jilan Jiang Tingting Ma Jiangyu Mao Guoxiong Wu | 2024 | Atmospheric and Oceanic Science Letters2024，17，1： | 0 |
| 19 | Impact of Perturbation Schemes on the Ensemble Prediction in a Coupled Lorenz Model显示文摘Based on a simple coupled Lorenz model,we investigate how to assess a suitable initial perturbation scheme for ensemble forecasting in a multiscale system involving slow dynamics and fast dynamics.Four initial perturbation approaches are used in the ensemble forecasting experiments:the random perturbation(RP),the bred vector(BV),the ensemble transform Kalman filter(ETKF),and the nonlinear local Lyapunov vector(NLLV)methods.Results show that,regardless of the method used,the ensemble averages behave indistinguishably from the control forecasts during the first few time steps.Due to different error growth in different time-scale systems,the ensemble averages perform better than the control forecast after very short lead times in a fast subsystem but after a relatively long period of time in a slow subsystem.Due to the coupled dynamic processes,the addition of perturbations to fast variables or to slow variables can contribute to an improvement in the forecasting skill for fast variables and slow variables.Regarding the initial perturbation approaches,the NLLVs show higher forecasting skill than the BVs or RPs overall.The NLLVs and ETKFs had nearly equivalent prediction skill,but NLLVs performed best by a narrow margin.In particular,when adding perturbations to slow variables,the independent perturbations(NLLVs and ETKFs)perform much better in ensemble prediction.These results are simply implied in a real coupled air–sea model.For the prediction of oceanic variables,using independent perturbations(NLLVs)and adding perturbations to oceanic variables are expected to result in better performance in the ensemble prediction. | Qian ZOU Quanjia ZHONG Jiangyu MAO Ruiqiang DING Deyu LU Jianping LI Xuan LI | 2023 | Advances in Atmospheric Sciences2023，40，3： | 0 |
| 20 | Factors responsible for the increasing trend of mei-yu season rainfall during 1979-2020 over the western and eastern mei-yu domain显示文摘近几十年来,江淮流域梅雨监测区(MMD)的梅雨期(6-7月)降水呈增加趋势.本文基于1979-2020年台站观测降水资料和ERA5再分析数据,从大气环流变异的角度揭示了这种长期增加趋势的主要影响因素.发现在MMD范围内,梅雨期降水趋势的增幅东部大于西部.水汽收支定量诊断表明,异常的蒸发和水汽平流对MMD西部和东部降水增加趋势的相对贡献是不同的.MMD西部(东部)的降水趋势主要归咎于增强的局地蒸发(增强的垂直水汽平流),后者又取决于MMD对流层中,低层的异常气旋环流.这种位于气候平均的西太平洋副热带高压西北侧的异常气旋有助于MMD东部600 hPa以上的水汽辐散增加,伴随加强的850 hPa水汽辐合,从而导致垂直水汽平流的增强.相反,该异常气旋则有利于增强MMD西部的局地蒸发. | Xuejie Zhao Guoxiong Wu Jiangyu Mao Yimin Liu Bian He | 2023 | Atmospheric and Oceanic Science Letters2023，16，3： | 0 |
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