珠江三角洲海平面上升对堤围防御能力的影响   总被引：13，自引：1，他引：12  

黄镇国  张伟强  赖冠文  罗少彤  范锦春  江沛霖 《地理学报》1999,54(6):518-525

珠江三角洲２０３０ 年海平面上升幅度约为３０ ｃｍ 。按此,由水力学模型计算了２４ 个站最高洪潮水位的升幅, 以５ ｃｍ 和２５ ｃｍ 等值线划分出影响很小区、影响较大区、影响最大区。由水文学方程计算了１７ 个站４ 种重现期的最高洪潮水位升幅, 得知现有堤围的防御标准在影响较大区将降低半个等级, 在影响最大区将降低一个半等级。受影响的堤围长度为２ ６０８ ｋｍ , 维护工作量为１ ７５２×１０４ｍ ３, 需投资２１ 亿元  相似文献   

A sea-level test for inertial interchange true polar wander events     

Jon E. Mound  Jerry X. Mitrovica  David A. D. Evans  & Joseph L. Kirschvink 《Geophysical Journal International》1999,136(3):F5-F10

The possibility of inertial interchange true polar wander (IITPW) events, in which the rotation pole moves 90° with respect to the solid Earth in a matter of ∼10  Myr, has been discussed in the geophysical literature for more than three decades. Recent evidence for an IITPW event in Early Cambrian time has renewed interest in the issue; however, the veracity of supporting palaeomagnetic evidence remains a matter of significant debate. We propose that sea-level variations driven by polar wander provide an important independent test for the occurrence of IITPW events. Our numerical simulations of the response of a viscoelastic planet to an IITPW-induced forcing predict sea-level changes of up to 200  m, depending on the details of the earth model, the location of the site relative to the rotation path and the elapsed time for the reorientation of the pole. A preliminary comparison of our predictions to Early–Middle Cambrian sea-level records for Australia, Laurentia and Baltica shows qualitative agreement. This comparison suggests that a definitive test for the Cambrian IITPW hypothesis is possible given a sufficiently accurate, and globally distributed, database of sea-level histories.  相似文献   

全球热带SSTA与中国7月降水和气温的伴随相关型分析   总被引：1，自引：1，他引：0  

吴洪宝  段安民 《南京气象学院学报》1998,21(3):418-423

用伴随相关型（ＡＣＰ）分析了中国７月降水和气温与全球热带ＳＳＴＡ的ＰＯＰ（主振荡型）间的关系,得到当两个典型的传播ＰＯＰ处在Ｅ１Ｎｉｎｏ事件发展相位时中国夏季总体呈南北旱,中间涝的形势,其中江淮流域,华中,东北东部和西北大部为降水正距平,华北,华南为负距平,降水偏多（少）时相应的气温偏低（高）,当两个传播型的典型模态处于ＬａＮｉｎａ事件发展相位时情况则相反。  相似文献   

    

Li Chongyin 《大气科学进展》1998,15(1):31-40

The data analyses found at first that the air—sea system in the northwestern Pacific region has clear systematical quasi—decadal oscillation, such as the surface air temperature, the subtropical high activities over the northwestern Pacific and the SSTA which has different time-scale features from the temporal variation with 3–4 years period of SSTA in the equatorial Pacific. In East Asia, the climate variations, such as the surface air temperature, the precipitation and the beginning date of Mei-yu in the Yangtze River basin, also have clear quasi-decadal oscillation. They can be regarded as the influences of quasi-decadal oscillation of air-sea system in the northwestern Pacific region. This research was supported by the Chinese Academy of Sciences and ‘95’ National Project- “Short-Range Climate Production System”.  相似文献   

NUMERICAL STUDY ON THE EFFECTS OF SEA SURFACE TEMPERATURE ON TROPICAL CYCLONE INTENSITY-PART I:NUMERICAL EXPERIMENT OF THE TROPICAL CYCLONE INTENSITY RELATED TO SST Duan Yihong;Qin Zenghao;Gu dianfeng;Li Yongping, Shanghai Typhoon Institute.Shangh     

端义宏  秦曾灏  顾建峰  李永平 《Acta Meteorologica Sinica》1998,(2)

In the context of a model of tropical cyclone intensity based on an improved meso-scaleatmospheric model, numerical simulation is performed of the track and intensity variation oftropical cyclones (TC) arising from sea surface temperature (SST) variation over a specified searegion. Evidence suggests that the model is capable of modeling quite welt the track and intensityof TC: SST variation leads to an abrupt change in the cyclone intensity: the response of thecyclone to the abrupt SST change lasts 8—12 h.  相似文献   

NUMERICAL EXPERIMENT OF IMPACT OF SEA SURFACE TEMPERATURE IN SOUTH CHINA SEA AND WARM POOL/WEST PACIFIC ON EAST ASIAN SUMMER MONSOON   总被引：1，自引：0，他引：1  

陈隆勋  王予辉 《Acta Meteorologica Sinica》1998,(2)

By using the NCAR CCM1 model, we have designed six sensitive experiments, which areincreased and decreased SST (sea surface temperature) by 1℃ each in the SCS (South China Sea)and in the West Pacific warm pool, increased and decreased SST by 1℃ in the warm pool withincreased SST by 1℃ in the SCS. All experiments are integrated from April to July. Comparingwith the control experiment, we have analyzed the anomalies of the wind field at the upper andlower layers, the anomalies of the seasonal variability of the monsoon and precipitation for eachexperiment. In the result, we have found that the SST anomaly (SSTA) in the SCS greatly affectsthe seasonal variability of the SCS monsoon and precipitation in China, especially during the coldperiod of SST in the SCS. The impact of SSTA in the warm pool on SCS monsoon is also found.but is weak as compared to the effect of SST anomaly in the SCS. Besides, its impact on rainfall inChina is uncertain.  相似文献   

海温异常对热带内外环流相互作用影响的对比分析   总被引：5，自引：2，他引：3  

孙柏民  孙淑清 《大气科学》1998,22(1):83-96

运用ECMWF的风场和高度场及TBB资料,用相关方法对比分析了热带太平洋海温分布东冷西暖（1984～1985年冬季）和东暖西冷（1982～1983年冬季）两种不同背景下,热带西太平洋对流活动与中高纬环流在季内时间尺度下相互作用的特点。结果表明,不同的海温分布其对应的大尺度环流场包括Hadley和Walker环流的位置及强弱均有较大的差别。冬季热带西太平洋对流活动与热带外大气的季内相互作用过程也有明显差异。  相似文献   

Lithospheric Geothermal Structure in Yunnan, China   总被引：2，自引：0，他引：2  

Zhou Zhenheng  Xiang Caiying  and Deng WanmingSeismological Bureau of Yunnan Province  Kunming  China Institute of Geology  Chinese Academy of Sciences  Beijing  China 《中国地震研究》1998,(1)

In this paper,the characteristics of the lateral variations of the deep heat flow and Hthospheric geotemperature distribution in Yunnan have been studied,and the lithospheric geothermal structure has been divided into three types,i.e.the geothermal structure in the typical modern tectonically active region,transitional geological region and stable geological region.Finally,the relationship between the geotherm and seismicitv has been discussed.  相似文献   

Crustal accretion beneath the Koyna coastal region (India) and Late Cretaceous geodynamics     

A.P Singh  D.M Mall   《Tectonophysics》1998,290(3-4):285-297

In 1967 a major earthquake in the Koyna region attracted attention to the hitherto considered stable Indian shield. The region is covered by a thick pile of Deccan lava flows and characterized by several hidden tectonic features and complex geophysical signatures. Although deep seismic sounding studies have provided vital information regarding the crustal structure of the Koyna region, much remains unknown. The two available DSS profiles in the region have been combined along the trend of Bouguer gravity anomalies. Unified 2-D density modelling of the Koyna crust/mantle suggests a ca. 3 km thick and 40 km wide high velocity/high density anomalous layer at the base of the crust along the coastline. The thickness of this anomalous layer decreases gradually towards the east and ahead of the Koyna gravity low the layer ceases to be visible. Based on the seismic and gravity data interpretation in the geodynamical/rheological boundary conditions the anomalous layer is attributed to igneous crustal accretion at the base of the crust. It is suggested that the underplated layer is the imprint of the magmatism caused by the deep mantle plume when the northward migrating Indian plate passed over the Reunion hotspot.  相似文献   

张北6.2级地震发生在小震条带上   总被引：10，自引：4，他引：6  

刁桂苓  张四昌 《华北地震科学》1998,16(3):34-38

分析晋、冀、蒙交界地区的地震分布格局,发现张北地震前存在小地震条带。条带由２０余年持续发生的小震组成,与华北地壳应力场最大剪切应力方向相同,是燕山－渤海地震构造带的西延段落。６．２级强震发生在条的东端。文中讨论了张北地震地点预测失误的原因,提出采用地震学和地震地质学交叉,融合的思路,分析观今小地震活动图象、震源机制资料,从构造学,运动学,动力学角度,研究地壳深部地震构造的方法。  相似文献