登陆广东北上路径热带气旋强降水的分布特征     

龚月婷  程正泉  杨诗琪 《广东气象》2022,44(1):11-14

利用1981-2018年中国气象局上海台风研究所热带气旋最佳路径资料和国家基本气象站逐日降水资料,对登陆广东北上路径热带气旋活动及强降水特征进行统计分析.结果表明北上热带气旋从登陆时到登陆后48 h是陆地强降水产生的集中时段,登陆时24 h是陆地大暴雨最集中的时段.强降水从沿海向内陆逐渐减少,一般登陆后热带气旋持续时间...  相似文献   

辽宁北部典型流域水生态功能区水生态安全评价   总被引：1，自引：0，他引：1  

魏冉  ;李法云  ;谯兴国  ;王金龙  ;吕纯剑 《气象与环境学报》2014,30(3):106-112

基于流域水生态功能分区的水生态安全评价是指导流域水生态“分类、分区”综合管理的前提,本文在流域中小尺度上依据水生态空间格局分异的自然特征和社会属性,以辽河流域的清河和凡河支流为对象,在流域水生态功能三级分区的基础上,运用“压力-状态-响应模型”（PSR）,通过对流域社会经济压力指标、环境压力指标、城市发展指标、资源环境发展指标、投资指标、治理指标等因素分析,筛选出13个评价指标。利用生态安全综合指数法,将流域水生态安全划分为极不安全、不安全、基本安全、安全、非常安全五个级别。其中,清河流域Ⅳ-5-9、Ⅳ-5-10、Ⅳ-5-11、Ⅳ-5-12、Ⅳ-5-14区处于基本安全,Ⅳ-5-8、Ⅳ-5-13属于不安全;凡河流域4个水生态功能三级区中,Ⅳ-5-1、Ⅳ-5-2、Ⅳ-5-3区属于基本安全、Ⅳ-5-4区为较安全。基于水生态功能分区的水生态安全评价和级别划分可为辽河流域水生态保护与流域生态管理提供科学依据。  相似文献   

一个区域海-气耦合模式的建立:模式验证及其对热带气旋“云娜”的模拟   总被引：3，自引：1，他引：2  

黄伟  郑运霞  沈淇  于润玲 《海洋与湖沼》2014,45(3):443-452

本文以区域热带气旋模式(GRAPES-TCM)为基础,引入海洋环流模式(Estuarine,Coastal and Ocean Model(semi-implicit),ECOM-si)和Ocean Atmosphere Sea Ice Soil 3(OASIS3)耦合器,建立了一个区域海-气耦合模式。利用该模式对0414号热带气旋"云娜"进行了数值模拟,验证了模式的性能。结果表明,耦合模式模拟的"云娜"强度相比单独的大气模式更接近观测,单独大气模式模拟的近地面风场偏强,而耦合模式模拟的近地面风场的强度和非对称结构均与观测更为接近。数值实验中,"云娜"热带气旋过境引起的海表面温度的下降与实况接近,海表面温度下降引起的海-气热通量相比控制实验的结果明显下降,分析资料表明这一下降是合理的。海洋模式的引入导致了热带气旋"云娜"结构的变化,这种变化不但反应在径向风的减弱(强度下降),还反应在对流强度和最强对流发生位置的变化,并最终引起了热带气旋降水结构的改变。  相似文献   

论IPCC-AR4模式对影响西北太平洋热带气旋的大气动力环境场的气候特征模拟性能     

余锦华  赵晓彤  陈成 《海洋学报》2014,36(3):61-72

评估了23个IPCC-AR4模式在低纬地区1948—1999年7—9月大尺度环流场的模拟性能,重点关注西北太平洋区域的西太副高、季风槽以及台风活动海域的垂直风切变。结果显示,绝大多数模式的7—9月低纬地区500hPa平均高度场、850hPa风场空间分布与NCEP都具有很高的相似性,但大多模式500hPa高度场存在系统性偏低,而850hPa风场偏强。所有模式模拟的西北太平洋副高脊线与NCEP都有一致的西南-东北走向,但有些模式的脊线位置偏离NCEP的较远。有4个模式没有模拟出类似于NCEP的季风槽线。综合模式对夏季热带环流场、西北太平洋副热带高压、季风槽以及西北太平洋热带气旋活动关键区域垂直风切变气候特征的模拟性能,按性能优劣,排在前10的模式依次是mpi_echam5、cccma_t63、gfdl_cm2_1、cnrm_cm3、cccma_t47、ukmo_hadgem1、ingv_echam4、ncar_ccsm3_0、csiro_mk3_5、mri_cgcm2_3_2a;排在后6位的模式是inmcm3_0、iap_fgoals1_0_g、ipsl_cm4、miroc3_2_medres、giss_eh、giss_er。  相似文献   

Rare earth elements in cold seep carbonates from the southwestern Dongsha area,northern South China Sea     

《Marine and Petroleum Geology》2014

The circulation of methane-rich fluids at cold seeps often leads to the precipitation of seep carbonates close to the seafloor along continental margins, which can be used as records of past fluid seepage. Rare earth element (REE) concentrations in seep carbonates have been used to trace fluid sources and provide information on associated biogeochemical processes at cold seeps. The REE concentrations of a series of carbonates collected from cold seeps in the southwestern Dongsha area of the northern South China Sea are analyzed in this study. The total REE contents (ΣREE) of the seep carbonates analyzed show a wide variation from 17 ppm to 523 ppm with an average ΣREE value of 54 ppm, which are higher than the typical marine carbonate values of ∼28 ppm commonly reported and also higher than those of the carbonates from other cold seep areas. A positive correlation between Fe–Mn content and ΣREE was observed. These results suggest that the seep carbonates of this study were primarily controlled by the methane-derived fluid from which they precipitated. The Fe-rich dolomite and siderite, which are the main components of the carbonates, are responsible for the enrichment of the REE. A slight positive Ce anomaly observed in the shale-normalized REE patterns of the studied seep carbonates suggests that they formed in anoxic conditions, and the correlations between Ce/Ce* and La_N/Sm_N, Ce/Ce* and Dy_N/Sm_N, Ce/Ce* and ΣREE further reveal that the REE characteristics of most seep carbonate samples preserve the original redox conditions in which they precipitated and late diagenesis has had little effect on the REE. However, the REE characteristics of sub-samples DS2-2B, DS1-6A and DS1-7A are very different from those of the other sub-samples, indicating a greater impact of late diagenesis and post-oxidation favored REE enrichment.  相似文献   

Depositional characteristics and accumulation model of gas hydrates in northern South China Sea     

《Marine and Petroleum Geology》2014

The South China Sea (SCS) shows favorable conditions for gas hydrate accumulation and exploration prospects. Bottom simulating reflectors (BSRs) are widely distributed in the SCS. Using seismic and sequence stratigraphy, the spatial distribution of BSRs has been determined in three sequences deposited since the Late Miocene. The features of gas hydrate accumulations in northern SCS were systematically analyzed by an integrated analysis of gas source conditions, migration pathways, heat flow values, occurrence characteristics, and depositional conditions (including depositional facies, rates of deposition, sand content, and lithological features) as well as some depositional bodies (structural slopes, slump blocks, and sediment waves). This research shows that particular geological controls are important for the presence of BSRs in the SCS, not so much the basic thermodynamic controls such as temperature, pressure and a gas source. Based on this, a typical depositional accumulation model has been established. This model summarizes the distribution of each depositional system in the continental shelf, continental slope, and continental rise, and also shows the typical elements of gas hydrate accumulations. BSRs appear to commonly occur more in slope-break zones, deep-water gravity flows, and contourites. The gas hydrate-bearing sediments in the Shenhu drilling area mostly contain silt or clay, with a silt content of about 70%. In the continental shelf, BSRs are laterally continuous, and the key to gas hydrate formation and accumulation lies in gas transportation and migration conditions. In the continental slope, a majority of the BSRs are associated with zones of steep and rough relief with long-term alternation of uplift and subsidence. Rapid sediment unloading can provide a favorable sedimentary reservoir for gas hydrates. In the continental rise, BSRs occur in the sediments of submarine fans, turbidity currents.  相似文献   

CLIMATE PREDICTION EXPERIMENT FOR TROPICAL CYCLONE GENESIS FREQUENCY USING THE LARGE-SCALE CIRCULATION FORECAST BY A COUPLED GLOBAL CIRCULATION MODEL   总被引：1，自引：1，他引：0  

贾小龙  陈丽娟  罗京佳 《热带气象学报(英文版)》2014,20(2):103-111

Based on an analysis of the relationship between the tropical cyclone genesis frequency and large-scale circulation anomaly in NCEP reanalysis, large-scale atmosphere circulation information forecast by the JAMSTEC SINTEX-F coupled model is used to build a statistical model to predict the cyclogenesis frequency over the South China Sea and the western North Pacific. The SINTEX-F coupled model has relatively good prediction skill for some circulation features associated with the cyclogenesis frequency including sea level pressure, wind vertical shear, Intertropical Convergence Zone and cross-equatorial air flows. Predictors derived from these large-scale circulations have good relationships with the cyclogenesis frequency over the South China Sea and the western North Pacific. A multivariate linear regression （MLR） model is further designed using these predictors. This model shows good prediction skill with the anomaly correlation coefficient reaching, based on the cross validation, 0.71 between the observed and predicted cyclogenesis frequency. However, it also shows relatively large prediction errors in extreme tropical cyclone years （1994 and 1998, for example）.  相似文献   

NUMERICAL ANALYSIS ON THE ROLE OF TROPICAL STORM NAMTHEUN IN THE UNUSUAL TRACKS OF THREE TROPICAL CYCLONES IN 2010     

白莉娜  马雷鸣  曾智华  黄伟  王栋梁 《热带气象学报(英文版)》2014,20(4):297-307

Tropical cyclones (TCs) Lionrock, Kompasu, and Namtheun were formed successively within 40 hours in 2010. Over the next several days afterwards, these TCs exhibited unusual movements which made operational prediction difficult. Verifications are performed on the forecasts of the tracks of these TCs with six operational models, including three global and three regional models. Results showed that the trends of TC tracks could be reproduced by these models, whereas trajectory turning points and landfall locations were not simulated effectively. The special track of Lionrock should be associated with its direct interaction with Namtheun, according to a conceptual model of binary TC interaction. By contrast, the relation between Kompasu and Namtheun satisfied the criteria for a semi-direct interaction. Numerical experiments based on the Global and Regional Assimilation and Prediction System-Tropical Cyclone forecast Model (GRAPES-TCM) further confirmed the effect of Namtheun on the unusual tracks of Lionrock and Kompasu. Finally, the physical mechanism of binary TC interaction was preliminarily proposed.  相似文献   

利用TMI反演的水汽凝结物对热带气旋潜热结构分布的探索研究   总被引：3，自引：0，他引：3  

姚小娟  黎伟标  陈淑敏 《大气科学》2014,38(5):909-923

本文利用热带测雨卫星TRMM（Tropical Rainfall Measuring Mission）微波成像仪TMI（TRMM Microwave Imager）2A12 水汽凝结物（Hydrometeor）反演资料,对西北太平洋地区从1998～2009 年的236 个热带气旋个例的1776 个“快照”（snapshot）的水汽凝结物的结构特征进行了分析,并探讨了水汽凝结物的时空变化与热带气旋强度演变联系。研究结果表明:（1）TMI 2A12 水汽凝结物资料显示出了热带气旋内部的细致结构及变化特征,水汽凝结物的峰值集中于数十公里到一百多公里的热带气旋眼壁及云墙区;在热带气旋发展过程中,随着热带气旋强度的增强,水汽凝结物增多且往其中心靠拢,从发展阶段到成熟阶段,水汽凝结物的大值中心基本上集中在距离热带气旋中心约50 km 区域,而且强度越强的热带气旋,水汽凝结物的大值中心与热带气旋中心的距离越近;在热带气旋消亡的过程中,水汽凝结物不断减弱且往外围扩散,逐渐扩展到远离中心的区域;（2）热带气旋强度与水汽凝结物的分布关系密切,热带气旋强度变化与热带气旋中心附近200 km 范围内的水汽凝结物含量存在显著的正相关,而200 km 以外的外围水汽凝结物含量存在负相关;（3）热带气旋强度变化与水汽凝结物的变化存在时间差,水汽凝结物的变化超前于热带气旋强度的变化,在热带气旋迅速发展之前数小时,热带气旋中心0～50 km 环状区域的水汽凝结物含量就已经提前增加了,在热带气旋减弱前数小时到十数小时,即使热带气旋还处于它强度的鼎盛时期,其中心0～50 km 环状区域的水汽凝结物含量就已经提前显著减少了,这种水汽凝结物的变化超前于热带气旋强度的变化的现象,可能是热带气旋强度预报的潜在线索。  相似文献   

我国北方地区冬小麦干旱灾害风险评估   总被引：7，自引：0，他引：7  

张存杰  王胜  宋艳玲  蔡雯悦 《干旱气象》2014,32(6):883-893

选取我国粮食重要生产区——北方冬麦区作为研究区,基于干旱灾害对作物产量的影响开展冬小麦干旱灾害风险评估和区划。在确定干旱灾害危险性指标过程中,通过对比分析MCI、CWDIa、CI、Pa及Ma干旱指数的适应性,确定了干旱灾害风险危险性指数;在分析北方冬麦区干旱背景和脆弱性时,考虑了冬麦区的地形、土壤类型、土壤有效持水量、河网水系、灌溉条件、降水量及干燥度等环境因素,以及冬小麦的耕地面积、播种面积、主要生育期的水分敏感系数、历史产量等。与以往致灾因子危险性分析方法不同,本文首先建立了干旱指标与冬小麦减产率之间的关系,通过减产率等级来确定干旱致灾临界阈值,在此基础上计算分析了冬小麦全生育期和6个关键生育期不同等级干旱发生的频率。综合考虑干旱发生的危险性、不同地区干旱背景和脆弱性,建立了我国北方冬麦区全生育期和6个关键生育期的干旱灾害风险评估模型和区划方法,实现了我国北方冬麦区干旱灾害的风险评估和区划。结果表明,MCI更能反映北方冬麦区干旱的特征,故以MCI指数作为干旱灾害风险危险性指数;我国北方冬麦区中北部的干旱灾害风险较高,应该加强防旱抗旱能力建设,南部地区包括苏皖和河南东南部的干旱灾害风险较小。本文建立的北方冬麦区不同生育期干旱灾害风险评估模型可应用于干旱灾害风险动态评估实时业务中。  相似文献