NUMERICAL STUDY ON FUNCTIONS AFFECTING TROPICAL CYCLONE STRUCTURE AND MOTION*

By using a beta-plane quasigeostrophic barotropic model,four numerical experiments with integration time more than five days are performed.Results show that the vorticity advection term and beta term are two basic factors significantly affecting tropical cyclone structure and motion.     

Holocene History of the Chocó Rain Forest from Laguna Piusbi, Southern Pacific Lowlands of Colombia

A high-resolution pollen record from a 5-m-long sediment core from the closed-lake basin Laguna Piusbi in the southern Colombian Pacific lowlands of Chocó, dated by 11 AMS¹⁴C dates that range from ca. 7670 to 220¹⁴C yr B.P., represents the first Holocene record from the Chocó rain forest area. The interval between 7600 and 6100¹⁴C yr B.P. (500–265 cm), composed of sandy clays that accumulated during the initial phase of lake formation, is almost barren of pollen. Fungal spores and the presence of herbs and disturbance taxa suggest the basin was at least temporarily inundated and the vegetation was open. The closed lake basin might have formed during an earthquake, probably about 4400¹⁴C yr B.P. From the interval of about 6000¹⁴C yr B.P. onwards, 200 different pollen and spore types were identified in the core, illustrating a diverse floristic composition of the local rain forest. Main taxa are Moraceae/Urticaceae,Cecropia,Melastomataceae/Combretaceae,Acalypha, Alchornea,Fabaceae,Mimosa, Piper, Protium, Sloanea, Euterpe/Geonoma, Socratea,andWettinia.Little change took place during that time interval. Compared to the pollen records from the rain forests of the Colombian Amazon basin and adjacent savannas, the Chocó rain forest ecosystem has been very stable during the late Holocene. Paleoindians probably lived there at least since 3460¹⁴C yr B.P. Evidence of agricultural activity, shown by cultivation ofZea maissurrounding the lake, spans the last 1710 yr. Past and present very moist climate and little human influence are important factors in maintaining the stable ecosystem and high biodiversity of the Chocó rain forest.     

华中华东地区上空水汽平衡状况

华中华东地区,为我国纬度较低,涨岸线最长的地区。该区雨水资源,地表水资源量均居全国之首。其维系因子－空中水汽,业经本文计算,其年总蓄留量＋１９７７４．５４亿ｍ＾３,相当水深１３９７ｍｍ,为水资源总量的１．７６倍,全国第一。     

用数字云图确定热带气旋强度的原理和方法

本文采用数字云图资料，分析热带气旋强度与热带气旋中云系结构的关系，提出了云系结构紧密度因子的概念并用云带旋转的圈数表示热带气旋强度的方法。本文对原有关于热带气旋中云系结构的某些因子的取值作了适当调整， 改进了用增强红外云图确定热带气旋强度的方法。 经过对2446组样本的拟合，热带气旋强度最大风速估计值的平均绝对误差为2.48 m/s。本方法可以实现人机交互，能更客观地作出定量估计。对1993年12个热带气旋检验，最大风速平均绝对误差为2.31 m/s。     

西太平洋上层海水溶解甲烷浓度及碳同位素特征研究

对西太平洋上层海水溶解甲烷浓度的研究结果表明，该海域海水甲烷相对于大气甲烷是强烈过饱和的。甲烷浓度及碳同位素组成特征表明这部分甲烷为生物成因。该海域海－气交换过程中甲烷通量在０．７～１０．４ｎｍｏｌｍ－２ｓ－１，明显高于其它开放海域。     

1994年影响山东的热带气旋分析

１９９４年为影响我国的热带气旋明显偏多年。利用常规天气图和海温资料，对本年度登陆北上热带气旋偏多的环流背景和海温场特征进行了分析，指出，西太平洋副热带高压稳定偏北和海面温度明显偏高，是北上热带气旋偏多的主要原因。同时，还对热带气旋移动路径、所在位置与山东降水的时空分布及降水强度之间的关系进行了简单的统计分析，其结果可供热带气旋的业务预报参考。     

中国热带气旋暴雨洪水的分布和水文特性

描述了由热带气旋形成和影响的暴雨及其洪水的地域分布,给出了区划;讨论了热带气旋暴雨洪水的水文特性,并与非热带气旋暴雨洪水作了比较。     

盛夏中国北方的超强区域性持续暴雨

将“６３．８暴雨”与“７５．８暴雨”的天气学特征作了系统的对比分析。研究表明：尽管这两次暴雨相隔１２年,主要暴雨落区相距５００ｋｍ以上,发生暴雨的低气压系统分别来自西南与东南等差别,而形成暴雨的基本天气学过程是非常相似的。概括这两次暴雨的环一种盛夏出现在中国北方的超强区域在气的概念模型。     

MULTI-OBJECTIVE PROGRAMMING MODEL OF TROPICAL CROPS IN HAINAN ISLAND

I.Introducti0I1Hail1al1isthelargnsttropicalislal1dwitllabundal1t11aturalrcsourccssuitablef0rgrowtllgtrol,icalcropsand\\4t11ven'highp0tentia1pr0d,uctivity.Hotx'cY'cr,t11c1-ca1'cstillsomeproblemsf(l)Tl1ese1ectionoflandsuitableforfqrestisn0tstrictalldPreservativerateoftr0picalcr0psislow,(2)Mostoftropicalcr0psarecollccntratcdillthezoneofeastern"windgap"andnorthern"frigidplace"andtheirsecurityisnotstable,(3)Rubberareaaccountsforab0uttwo-thirdsoftl1etotalarea0ftropica1crops,henceproportiondis1ocat…     

''98南海季风(SCSMEX)和高原科学试验(TIPEX)边界层

使用1998年南海季风(SCSMEX)试验和青藏高原科学试验(TIPEX)的边界层资料对Ekman特征进行了动力学研究。得到如下结果：(1)在青藏高原和南海及其周围区域有类似的Ekman动力学特征。(2)比较研究表明，边界层厚度在青藏高原约为2250m且考虑到它的摆动特性，其厚度可在2250-2750m之间。在热带西南太平洋边界层厚度约为2000m，其厚度摆动较小，在平原地区边界层厚度较低。（3）由于高原和热带海域海拔高度的不同，尽管在高原和热带海区有着几乎同样的边界层厚度，但边界层对大气的影响是相当不同的。考虑到海拔高度的影响，在这两个地区摩擦力作用的空间部位的高度有相当大的差别。(4)这两个区域的湍流摩擦的垂直结构差异较大。使用’98SCSMEX和TIPEX边界层资料计算结果表明，即使在低层，平均湍流粘性力在高原上是热带海域的2．3倍。