太平洋年代际振荡对冬季北半球两大洋风暴轴协同变化的可能影响          下载免费PDF全文

朱伟军  曹煜晨  李天宇  祁春娟 《大气科学学报》2019,42(6):892-901

利用NCEP/NCAR提供的再分析资料和NOAA提供的海温资料分析太平洋年代际振荡(Pacific Decadal Oscillation,PDO)不同位相的年代际背景下北半球海气耦合关系的异常与风暴轴协同变化的联系,主要结果如下:1)冬季太平洋年代际振荡与北半球两大洋风暴轴协同变化之间存在显著的相关关系,当PDO暖位相时,对应两大洋风暴轴南北位置反向的异常变化,其中北太平洋风暴轴偏南且中东部减弱,北大西洋风暴轴偏北且中东部增强,PDO冷位相时相反。2)PDO为暖位相时,对应El Niňo型海温异常,北大西洋海温呈三极型,平均槽脊加强,经向环流增强,极涡收缩,北太平洋风暴轴南压,大西洋风暴轴则北抬,此时欧亚大陆北部和北美大陆大部分地区温度异常升高,亚洲南部、非洲北部及巴伦支海以北的高纬温度异常降低,北美西南部和格陵兰岛附近温度也为异常降低,PDO冷位相时相反。  相似文献   

低温雨雪过程的粒子群-神经网络预报模型   总被引：3，自引：0，他引：3       下载免费PDF全文

陆虹  翟盘茂  覃卫坚  金龙  谢敏  钱晰  赵华生 《应用气象学报》2015,26(5):513-524

利用逐日气温和降水量数据、NCEP/NCAR再分析资料以及预报场资料,通过分析提取我国南方区域持续性低温雨雪过程及其预报因子,使用粒子群-神经网络方法建立非线性的统计集合预报模型 (PSONN-EPM),对我国南方区域持续性低温雨雪过程进行预报试验。结果表明:以过程的冷湿程度及影响范围为标准,将低温雨雪过程分为一般过程和严重过程,并建立不同的预报模型效果较好。通过10 d独立样本预报试验看,基于粒子群-神经网络方法建立的集合预报模型比基于逐步回归方法建立的预报模型的预报平均相对误差小,对严重过程预报能力高于对一般过程预报,且这种非线性统计集合建模方法在建模过程中不需要调整神经网络参数,在实际预报业务中值得尝试。  相似文献   

OBJECTIVE CLASSIFICATION OF THE TRACKS OF TROPICAL STORMS IN THE BAY OF BENGAL   总被引：1，自引：0，他引：1  

林志强  边巴扎西  文胜军  周振波 《热带气象学报(英文版)》2015,21(3):222-231

An objective analysis of tropical cyclone tracks is performed, with which the tracks of 131 tropical storms (TSs) in 1972-2011 are separated into three types that move west-, north- and northwestward, denoted as Types A, B and C, respectively. Type A (21 TSs and 16% of total) has the origin in the southwestern Bay of Bengal, with the TS in a unimodal distribution as its seasonal feature, occurring mainly in autumn; 18 of the 21 TSs (taking up 90%) land mostly on the western Bay coast (west of 85°E); 5% of Type-A TSs attains the wind speed of >42.7 to 48.9 m/s. Type A has little or no effect on Tibet. Type B (74 TSs, 56.6% of the total) has its preferable origin in the central Bay of Bengal, with the TS in a bimodal distribution as its seasonal pattern. This type denotes the travel in the north in spring, with the landfall of 67 of the 74 TSs (accounting for 91%) mainly on the middle coast of the Bay (85° to 95°E), and 19% of the TSs reaching the wind velocity of >42.7 to 48.9 m/s, which exert great effect on Tibet and it is this TS track that gives strong precipitation on its way through this region. Type C (36 TSs, 27.5% of the total) has its main origin in the southern part of the bay, and these TSs are formed largely in autumn, moving in the northwest direction, and 23 of the 36 TSs (64%) land mostly on the western Bay coast, lasting for a longer time, with almost no impact upon Tibet.  相似文献   

Impacts of Two Ice Parameterization Schemes on the Cloud Microphysical Processes and Precipitation of a Severe Storm in Northern China          下载免费PDF全文

YANG Hui-Ling  XIAO Hui  GUO Chun-Wei 《大气和海洋科学快报》2015,8(5)

A severe storm that occurred over Beijing in northern China on 23 June 2011 was simulated with two different ice crystal parameterization schemes(the DeMott scheme and Meyers scheme) by using the Regional Atmospheric Modeling System. Compared with the DeMott scheme, the simulation results with the Meyers scheme have the following characteristics:(1) Updrafts are stronger and more numerous;(2) The cloud is better organized and contains a greater peak of ice-phase hydrometeor mixing ratios;(3) Cloud water and hail mixing ratios increase while graupel mixing ratios decrease;(4) The surface precipitation is initially greater. However, at the end of the simulation, less precipitation is produced. In short, the differences between the two schemes are not obvious, but the De Mott scheme has a relatively more reasonable result.  相似文献   

Estimating Sea-Level Allowances for Atlantic Canada using the Fifth Assessment Report of the IPCC     

Li Zhai  Blair J.W. Greenan  John Hunter  Thomas S. James  Guoqi Han  Phillip MacAulay 《大气与海洋》2015,53(5):476-490

Abstract

Sea-level allowances at 22 tide-gauge sites along the east coast of Canada are determined based on projections of regional sea-level rise for the Representative Concentration Pathway 8.5 (RCP8.5) from the Fifth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC AR5) and on the statistics of historical tides and storm surges (storm tides). The allowances, which may be used for coastal infrastructure planning, increase with time during the twenty-first century through a combination of mean sea-level rise and the increased uncertainty of future projections with time. The allowances show significant spatial variation, mainly a consequence of strong regionally varying relative sea-level change as a result of glacial isostatic adjustment (GIA). A methodology is described for replacement of the GIA component of the AR5 projection with global positioning system (GPS) measurements of vertical crustal motion; this significantly decreases allowances in regions where the uncertainty of the GIA models is large. For RCP8.5 with GPS data incorporated and for the 1995–2100 period, the sea-level allowances range from about 0.5?m along the north shore of the Gulf of St. Lawrence to more than 1?m along the coast of Nova Scotia and southern Newfoundland.  相似文献   

冬季寒潮期间黄、渤海水位低频波动研究          下载免费PDF全文

李晓红  董礼先 《海洋与湖沼》2011,42(4):467-473

利用 POM(Princeton Ocean Model)海洋数值模式建立渤、黄、东海冬季三维环流动力学区域模型。模型在海-气边界使用包括风应力、气压和热通量的大气驱动, 海洋边界使用西太平洋模式提供的环流和潮位驱动, 综合模拟潮波运动、温度、盐度、环流变化和水位低频波动。 模拟了 2001 年 1 月寒潮过境时黄、 渤海水位低频波动及流场变化, 分析了其对大风过程、 气压、降温的响应, 发现冬季强劲的北风和西北风都可以通过抽吸振荡在渤、 黄海诱发水位的低频波动, 东北风则由于地形影响不能诱发渤、黄海的低频波动。气压和降温只是在波动幅度上有一定的影响。波动发源于渤海和北黄海, 最大波幅可以达到 0.6 m。波动进入南黄海后有沿黄海深槽西侧传播的倾向, 波动幅度在传播过程中逐渐减小。  相似文献   

The effect of wave-induced radiation stress on storm surge during Typhoon Saomai (2006)   总被引：5，自引：1，他引：4  

FENG Xingru  YIN Baoshu  YANG Dezhou  WILLIAM Perrie 《海洋学报(英文版)》2011,30(3):20-26

The effects of wave-induced radiation stress on storm surge were simulated during Typhoon Saomai using a wave-current coupled model based on ROMS (Regional Ocean Modeling System) ocean model and SWAN (Simulating Waves Nearshore) wave model.The results show that radiation stress can cause both set-up and set-down in the storm surge.Wave-induced set-up near the coast can be explained by decreasing significant wave heights as the waves propagate shoreward in an approximately uniform direction;wave-induced set-down far from the coast can be explained by the waves propagating in an approximately uniform direction with increasing significant wave heights.The shoreward radiation stress is the essential reason for the wave-induced set-up along the coast.The occurrence of set-down can be also explained by the divergence of the radiation stress.The maximum wave-induced set-up occurs on the right side of the Typhoon path,whereas the maximum wave induced set-down occurs on the left side.  相似文献   

Development and application of an operational tide and storm surge prediction model for the seas around Taiwan     

尤皓正  于嘉顺 《中国海洋工程》2011,25(4):591-608

Storm surges are abnormal rises in sea level along coastal areas and are mainly formed by strong wind and atmospheric depressions.When storm surges coincide with high tide,coastal flooding can occur.Creating storm surge prediction systems has been an important and operational task worldwide.This study developed a coupled tide and storm surge numerical model of the seas around Taiwan for operational purposes at the Central Weather Bureau.The model was calibrated and verified by using tidal records from seas around Taiwan.Model skill was assessed based on measured records,and the results are presented in details.At 3-minute resolution,tides were generally well predicted,with the root mean-square errors of less than 0.11 m and an overall correlation of more than 0.9.Storms(winds and depressions) were introduced into the model forcing by using the parameter typhoon model.Five typical typhoons that threatened Taiwan were simulated for assessment.The surges were well predicted compared with the records.  相似文献   

湛江红树林保护区现代沉积物粒度特征及其对风暴事件的响应   总被引：1，自引：0，他引：1  

许艳  王拓夫 《台湾海峡》2011,30(2):269-274

沉积物粒度是描述沉积环境的重要指标之一,利用沉积物粒度参数可以反演沉积物堆积过程、沉积水动力特征.通过对湛江红树林国家级自然保护内海湾、河口、潮坪区的红树林表层沉积物粒度分析的研究,结果表明：河口与海湾区的红树林沉积物以泥质为主;有堤坝保护的河口区红树林沉积物颗粒细,为悬移质体含量高且连续稳定的低能环境;红树林发育差的潮坪区红树林沉积物为砂含量较大且水动力较强的高能环境.并通过推算海湾区沉积物的沉积年代,结合样品粒度分析的结果得出了该地区风暴潮发生的大致时间.  相似文献   

2006年夏季福建近海台风风暴潮特征分析   总被引：1，自引：0，他引：1  

许金电  郭小钢  黄奖 《台湾海峡》2011,30(4):473-482

根据2006年夏季福建沿岸4个海洋观测站和福建近海5个潜标水位观测站的水位观测资料,分析了在4个热带气旋影响下的福建近海风暴潮特征．结果表明：福建沿岸海域的台风风暴潮大小不完全取决于台风强弱,与大风半径关系密切．若台风大风区覆盖整个台湾海峡,福建沿岸海域增水都较大,比如0604号强热带风暴“碧利斯”的大风区较大,由其引起厦门海洋观测站的最大增水高度达114em．0608号超强台风“桑美”和0609号强热带风暴“宝霞”双台风的大风区都比较小,由其引起的各测站增水相对也较小,增水高度最大的厦门海洋观测站只有52em．比较福建近海潜标水位观测站及其附近的海洋观测站采用11点（11h）滑动平均后的最大增水可知,福建近海潜标观测站台风增水高度（22～46cm）比沿岸海洋观测站的台风增水高度（62—73em）小40％左右．这表明台风增水有个向岸堆积的过程,即测站离岸越远,台风增水高度就越小．位于热带气旋（0605号台风“格关”）行进路径右侧的测站增水较大（平潭海洋观测站极值增水高度为49em,崇武海洋观测站极值增水高度为55em）,位于热带风暴行进路径左侧的测站增水较小（东山海洋观测站极值增水高度为45cm）．通过对0604号强热带风暴“碧利斯”引起的各测站增水滤除高频振荡后,福建沿岸海洋观测站最大增水高度从大到小依次为崇武站（74orfl）、平潭站（73em）、厦门站（68om）、东山站（62cm）,可见距离热带风暴中心越近（距离热带风暴中心从近到远依次为平潭、崇武、厦门、东山海洋观测站）,增水高度越大,反之,增水高度越小．台湾海峡地形和福建沿岸海域地形容易出现双（多）增水峰现象．通过对各测站台风增水时间序列进行最大熵谱分析可知,热带气旋容易引起福建沿岸和近海各测站台风增水出现周期为12．0h的振荡．  相似文献