Influence of the NAO on Wintertime Surface Air Temperature over East Asia: Multidecadal Variability and Decadal Prediction

In this paper,we investigate the influence of the winter NAO on the multidecadal variability of winter East Asian surface air temperature(EASAT)and EASAT decadal prediction.The observational analysis shows that the winter EASAT and East Asian minimum SAT(EAmSAT)display strong in-phase fluctuations and a significant 60-80-year multidecadal variability,apart from a long-term warming trend.The winter EASAT experienced a decreasing trend in the last two decades,which is consistent with the occurrence of extremely cold events in East Asia winters in recent years.The winter NAO leads the detrended winter EASAT by 12-18 years with the greatest significant positive correlation at the lead time of 15 years.Further analysis shows that ENSO may affect winter EASAT interannual variability,but does not affect the robust lead relationship between the winter NAO and EASAT.We present the coupled oceanic-atmospheric bridge(COAB)mechanism of the NAO influences on winter EASAT multidecadal variability through its accumulated delayed effect of~15 years on the Atlantic Multidecadal Oscillation(AMO)and Africa-Asia multidecadal teleconnection(AAMT)pattern.An NAO-based linear model for predicting winter decadal EASAT is constructed on the principle of the COAB mechanism,with good hindcast performance.The winter EASAT for 2020-34 is predicted to keep on fluctuating downward until~2025,implying a high probability of occurrence of extremely cold events in coming winters in East Asia,followed by a sudden turn towards sharp warming.The predicted 2020/21 winter EASAT is almost the same as the 2019/20 winter.     

Recent Progress in Studies of the Variabilities and Mechanisms of the East Asian Monsoon in a Changing Climate

Located in a monsoon domain,East Asia suffers devastating natural hazards induced by anomalous monsoon behaviors.East Asian monsoon(EAM)research has traditionally been a high priority for the Chinese climate community and is particularly challenging in a changing climate where the global mean temperature has been rising.Recent advances in studies of the variabilities and mechanisms of the EAM are reviewed in this paper,focusing on the interannual to interdecadal time scales.Some new results have been achieved in understanding the behaviors of the EAM,such as the evolution of the East Asian summer monsoon(EASM),including both its onset and withdrawal over the South China Sea,the changes in the northern boundary activity of the EASM,or the transitional climate zone in East Asia,and the cycle of the EASM and the East Asian winter monsoon and their linkages.In addition,understanding of the mechanism of the EAM variability has improved in several aspects,including the impacts of different types of ENSO on the EAM,the impacts from the Indian Ocean and Atlantic Ocean,and the roles of mid-to high-latitude processes.Finally,some scientific issues regarding our understanding of the EAM are proposed for future investigation.     

Extreme Cold Events from East Asia to North America in Winter 2020/21: Comparisons,Causes, and Future Implications

Three striking and impactful extreme cold weather events successively occurred across East Asia and North America during the mid-winter of 2020/21.These events open a new window to detect possible underlying physical processes.The analysis here indicates that the occurrences of the three events resulted from integrated effects of a concurrence of anomalous thermal conditions in three oceans and interactive Arctic-lower latitude atmospheric circulation processes,which were linked and influenced by one major sudden stratospheric warming(SSW).The North Atlantic warm blob initiated an increased poleward transient eddy heat flux,reducing the Barents-Kara seas sea ice over a warmed ocean and disrupting the stratospheric polar vortex(SPV)to induce the major SSW.The Rossby wave trains excited by the North Atlantic warm blob and the tropical Pacific La Nina interacted with the Arctic tropospheric circulation anomalies or the tropospheric polar vortex to provide dynamic settings,steering cold polar air outbreaks.The long memory of the retreated sea ice with the underlying warm ocean and the amplified tropospheric blocking highs from the midlatitudes to the Arctic intermittently fueled the increased transient eddy heat flux to sustain the SSW over a long time period.The displaced or split SPV centers associated with the SSW played crucial roles in substantially intensifying the tropospheric circulation anomalies and moving the jet stream to the far south to cause cold air outbreaks to a rarely observed extreme state.The results have significant implications for increasing prediction skill and improving policy decision making to enhance resilience in“One Health,One Future”.     

自动气象站出现故障编发报文的几种方法

1引言伊春自动气象站是国家基本站(现改为一级站),每天担负8次天气报,资料参加全球交换。当计算机出现故障时,天气报是否能在规定的时间内准确的编发出是至关重要的。出现故障时,在短时间内准确的手工编发出报文难度很大,容易出现错情或造成迟报等重大错情。为了避免这种情况的发生,总结了以下几种方法进行编发报,降低了出错的几率。     

Forecasting Quasi-stationary Front Rainstorm in Southeast China Using Synthetically Multilevel Analog Forecast Technology

The authors use numerical model integral products in a third level forecast of synthetically multi-level analog forecast technology.This is one of the strongest points of this study,which also includes the re-ducing mean vacant-forecast rate method,which pos-sesses many advantages with regard to filtering the analog term.Moreover,the similitude degree between samples is assessed using a combination of meteorological elements,which works better than that described using a single element in earlier analog forecast studies.Based on these techniques,the authors apply the model output,air sounding,surface observation and weather map data from 1990 to 2002 to perform an analog experiment of the quasi-stationary front rainstorm.The most important re-sults are as follows:(1) The forecast successful index is 0.36,and was improved after the forecast model was re-vised.(2) The forecast precise rate (0.59) and the lost-forecast rate (0.33) are also better than those of other methods.(3) Based on the model output data,the syn-thetically multilevel analog forecast technology can pro-duce more accurate forecasts of a quasi-stationary front rainstorm.(4) Optimal analog elements reveal that trig-gering mechanisms are located in the lower troposphere while upper level systems are more important in main-taining the phase of the rainstorm.These variables should be first taken into account in operational forecasts of the quasi-stationary front rainstorm.(5) In addition,experi-ments reveal that the position of the key zone is mainly decided by the position of the system causing the heavy rainfall.     

巧修虹吸雨量计浮子

地面气象常规仪器的零配件近年来十分紧缺,特别是虹吸雨量计的浮子。浮子是虹吸雨量计中最重要的零件,而浮子又最容易冻坏。例如,牡丹江地区2005年5月6～9日4d内,先是下了雨,后又转雨加雪、雪,绥芬河站的降水量近30mm。温度最低降到1.6℃,虹吸雨量计的安装时间和拆卸时间很难掌握,安装太迟或拆卸太早都可能影响到年度15个时段最大降水量的挑选。由于气候变化和人为因素造成浮子冻坏的现象屡见不鲜,一旦浮子底部冻裂而又没有备份浮子,为了气象资料的完整性可采取巧焊浮子的方法,焊好待用,有了新的浮子再更新。     

江西省2006年1-12月自然灾害公报(摘录)

受气候异常影响,2006年江西自然灾害总体发生水平与常年相比,属偏重发生年份。全省自然灾害主要以台风、暴雨洪涝、雷电、地质灾害、农林生物灾害为主。其中风雹、雷电灾害频繁,雷电死亡人数     

The Sensitive Regions Identified by CNOPs of Three Typhoon Events

In this paper, several sets of observing system simulation experiments (OSSEs) were designed for three typhoon cases to determine whether or not the additional observation data in the sensitive regions identified by conditional nonlinear optimal perturbations (CNOPs) could improve the short-range forecast of typhoons. The results show that the CNOPs capture the sensitive regions for typhoon forecasts, which implies that conducting additional observation in these specific regions and eliminating initial errors could reduce forecast errors. It is inferred from the results that dropping sondes in the CNOP sensitive regions could lead to improvements in typhoon forecasts.     

Ocean Response to a Climate Change Heat-Flux Perturbation in an Ocean Model and Its Corresponding Coupled Model

State-of-the-art coupled general circulation models(CGCMs)are used to predict ocean heat uptake(OHU)and sealevel change under global warming.However,the projections of different models vary,resulting in high uncertainty.Much of the inter-model spread is driven by responses to surface heat perturbations.This study mainly focuses on the response of the ocean to a surface heat flux perturbation F,as prescribed by the Flux-Anomaly-Forced Model Intercomparison Project(FAFMIP).The results of ocean model were compared with those of a CGCM with the same ocean component.On the global scale,the changes in global mean temperature,ocean heat content(OHC),and steric sea level(SSL)simulated in the OGCM are generally consistent with CGCM simulations.Differences in changes in ocean temperature,OHC,and SSL between the two models primarily occur in the Arctic and Atlantic Oceans(AA)and the Southern Ocean(SO)basins.In addition to the differences in surface heat flux anomalies between the two models,differences in heat exchange between basins also play an important role in the inconsistencies in ocean climate changes in the AA and SO basins.These discrepancies are largely due to both the larger initial value and the greater weakening change of the Atlantic meridional overturning circulation(AMOC)in CGCM.The greater weakening of the AMOC in the CGCM is associated with the atmosphere–ocean feedback and the lack of a restoring salinity boundary condition.Furthermore,differences in surface salinity boundary conditions between the two models contribute to discrepancies in SSL changes.     

秋天

风就那么轻轻地扇了一下,整个荒原就着了火,不停奔忙的救火人却面带微笑。站在垄上,我的心在随着他们的韵律激动地博跳。金黄色玉米,黄金样水稻,所有的稼禾都积极地     

南方上半月连日阴雨 北方下半月气温偏高——2002年5月

今年 5月 ,与常年同期相比 ,除东北大部、华北北部、华南东部、内蒙古东部和南疆大部等地降水明显偏少外 ,我国其余大部地区降水偏多或接近常年。本月全国大部地区气温接近常年或偏低 ,其中黄淮西部、江淮大部、西南地区东部、湖北和湖南北部等地的气温偏低 1～ 2℃ ,东北和华南东部沿海偏高 1～ 2℃。本月有一个热带风暴生成。1　天气概况5月份降水量 ,西南东部地区、黄淮大部及其以南地区在 10 0ｍｍ以上 ,其中江南及重庆大部、贵州大部、云南西南部、广西、广东中部等地一般有 2 0 0～ 330ｍｍ ,局部地区达 330～ 4 70ｍｍ ;东北、华北、…     

鲁中山区东北部丘陵地区霜冻特征分析

利用临朐县1980-2008年29年间作物生育季节3—11月的所有“黑、白”霜观测记录,对鲁中山区东北部丘陵地区霜冻进行统计分析。结果表明,鲁中山区东北部丘陵地区霜冻有明显的地域特征,即霜冻危害较重的季节在3—4月份;霜冻类型以辐射霜冻为主;霜冻发生的气候特征与当地地形地貌密切相关;从而为鲁中山区东北部丘陵地区霜冻的预测预报提供可靠的依据。     

Fluctuations in the length of the growing season in Minnesota

Fluctuations in growing season length and in the dates of the last spring freeze and first fall freeze between 1899 and 1982 were studied for five rural Minnesota stations with long, high quality records. A general increase in growing season length was found, but there was substantial variation in the pattern of fluctuations among the stations. The increase in growing season length is not clearly and uniformly related to changes in the dates of first and last freezes. The interannual variability of growing season duration is on the order of the increase in duration so that the change would not be readily apparent to a casual observer. Our results do not correspond well with certain other studies of growing season length nor with fluctuations in hemispheric mean temperature. We conclude that extreme care must be used in extrapolating results of growing season length studies in space and in relating them to mean temperature fluctuations.     

2002年夏季山东干旱成因分析

分析了山东省 2 0 0 2年夏季降水、气温特点和干旱情况 ,并从大气环流、北太平洋SST、气候背景等方面对少雨干旱气候的影响进行了分析 ,指出冬季大气环流、北太平洋SST对山东夏季旱涝趋势的预测具有重要的指示意义。     

2014年初冬牡丹江市暴雪天气诊断分析

本文利用常规资料及数值预报产品,对2014年12月1日牡丹江出现的暴雪天气过程进行诊断分析,结果表明:高空阶梯槽的形成和维持,为暴雪提供了有利的环流背景,中低空切变线和低压倒槽是主要影响系统,为暴雪产生提供强的辐合上升运动和水汽条件;冷平流的持续使近地面气温降至0℃以下,保证了降雪所需要的温度条件。     

1994年冬季洛阳机场天气之特点

主要用洛阳15年冬季能见度资料对比,提出1994年11月-12月出现多日大雾天气在历史上是少见的.通过分析1994年几例典型大雾形成的具体特点和影响因素及天气形势.指出稳定层的存在,适宜的地面气压场是导致大雾的直接原因.     

1994年冬季洛阳机场天气之特点

主要用洛阳１５ 年冬季能见度资料对比,提出１９９４ 年１１ 月—１２ 月出现多日大雾天气在历史上是少见的。通过分析１９９４ 年几例典型大雾形成的具体特点和影响因素及天气形势。指出稳定层的存在,适宜的地面气压场是导致大雾的直接原因     

Fronts in the vicinity of the tropopause

Summary From a study of five cases of pronounced fronts in the upper troposphere, it is concluded that the waterspout model offers the most satisfactory solution to the problem of connecting frontal boundaries and tropopauses. Composite cross sections of temperature, potential temperature, normal wind component and potential vorticity are presented for the five cases. On the basis of the potential vorticity measurements it is suggested that the most likely explanation for the formation of the high-level front is a folding of the tropopause.

---

Zusammenfassung Auf Grund einer Untersuchung von fünf Fällen ausgesprochener Fronten in der höheren Troposphäre wird der Schluß gezogen, daß die Wasserhosen-Vorstellung am besten den Zusammenhang zwischen Fronten und Tropopausen darstellt. Kombinierte Querschnitte von Temperatur, potentieller Temperatur, normaler Windkomponente und potentieller Vorticity werden für die fünf Fälle vorgelegt. Auf Grund der Bestimmungen der potentiellen Vorticity wird dargelegt, daß die wahrscheinlichste Erklärung für die Entstehung einer Front in der Höhe in der Annahme einer Faltung der Tropopause besteht.

---

Résumé En se fondant sur cinq cas de fronts très nets de la haute troposphère, les auteurs concluent que le schéma de trombe constitue la meilleure solution pour représenter la liaison entre zones frontales et tropopause. Ils donnent des profils combinés de température, de température potentielle, de composantes normales du vent et de vorticity potentielle pour les cinq cas. Ils montrent à l'aide de mesures de la vorticity potentielle que l'explication la plus probable de la formation d'un front en altitude consiste à admettre un plissement de la tropopause.

---

---

With 11 Figures

---

Contribution No. 37, Department of Meteorology and Climatology. —The research reported in this article has been supported by the Geophysical Research Directorate, Air Force Cambridge Research Center, under Contract No. AF 19 (604)-1811.     

Atomic mercury distribution features in the surface air layer in the Sea of Japan in the fall of 2010

Presented are the results of mercury content measurements in the surface air layer in the Sea of Japan in the period from October 27 to November 11, 2010. It is revealed that the mercury content varied from 0.6 to 3.8 ng/m³. It is demonstrated that the mercury concentration distribution has geographical zoning and depends on the movement of air masses and on the closeness of anthropogenic sources. The maximum mercury concentration is detected in the central part of the sea at the southwestern and southern directions of the wind, that is associated with the industrial emissions of East Asia countries. The minimum mercury concentration corresponding to the concentration in the surface air layer of the Arctic, Atlantic Ocean (Northern Hemisphere), and the Sea of Okhotsk and Bering Sea was observed along the coast of Primorye at the northwestern wind direction.     

On the role of a monsoon factor in the variability of currents in the Indian Ocean

On the basis of long series of contemporary instrumental measurements, the dynamics of waters in the western boundary current of the Indian Ocean is studied. For the first time, the background (quasi-stationary) circulation is estimated, and summer and winter monsoon components of the velocity field are detected. It is shown that the features of water dynamics of the Somali Current pattern are caused by the intensification of circulation during the summer phase, when the background and monsoon velocity fields with the same sign of vorticity are superimposed on each other. During the winter phase, on the contrary, superposition of background and monsoon circulations, with the opposite signs, is associated with a weakening of the resultant velocity of the currents.