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971.
The impacts of the enhanced model's moist physics and horizontal resolution upon the QPFs(quantitative precipitation forecasts)are investigated by applying the HIRLAM(high resolutionlimited area model)to the summer heavy-rain cases in China.The performance of the control run,for which a 0.5°×0.5°grid spacing and a traditional“grid-box supersaturation removal+Kuo typeconvective paramerization”are used as the moist physics,is compared with that of the sensitivityruns with an enhanced model's moist physics(Sundqvist scheme)and an increased horizontalresolution(0.25°×0.25°),respectively.The results show:(1)The enhanced moist physics scheme(Sundqvist scheme),by introducing the cloud watercontent as an additional prognostic variable and taking into account briefly of the microphysicsinvolved in the cloud-rain conversion,does bring improvements in the model's QPFs.Althoughthe deteriorated QPFs also occur occasionally,the improvements are found in the majority of thecases,indicating the great potential for the improvement of QPFs by enhancing the model's moistphysics.(2)By increasing the model's horizontal resolution from 0.5°×0.5°,which is already quitehigh compared with that of the conventional atmospheric soundings,to 0.25°×0.25°without thesimultaneous enhancement in model physics and objective analysis,the improvements in QPFs arevery limited.With higher resolution,although slight amelioration in locating the rainfall centersand in resolving some finer structures of precipitation pattern are made,the number of the mis-predicted fine structures in rainfall field increases with the enhanced model resolution as well. 相似文献
972.
中国华北地区壳内低速高导层(体)成因模式的探讨 总被引:5,自引:0,他引:5
依据高温高压下华北地区地壳主要岩石的物理性质-波速,电性测定的结果,提出了华北地区低速高导层可能的成因模式以及不同模式的适应范围。认为;碳酸盐岩在深部一定温度,压力和氧逸度条件下碳的析出会导致高导层体的出现;深部韧性剪切带组成矿物的定向排列,可使岩石的波速,电生产生各向异性行为,导致低速高导层的产生;绿片岩相和角闪岩相石中含水矿物的脱水作用会导致上,中地壳岩石物理力学性质的突变,这可能是该地区低速 相似文献
973.
ABSTRACT The High Himalayan Crystallines (HHC) of SE Zanskar consist of biotite paragneisses, of orthogneisses that derive from early-Palaeozoic granitoids, of minor metabasics and of post-metamorphic leucogranites of Miocene age. Two main metamorphic events have been documented in the HHC. The first event occurred at P= 12.0 ± 0.5 kbar and T= 750 ± 50° C in rare metabasics intruded by early-Palaeozoic granitoids. In the biotite paragneisses, thermobarometric estimates of the first event point to comparable T at P 4–5 kbar lower. The first event is followed by a pervasive syn-tectonic crystallization characterized by lower P and T. On the basis of the cooling ages of the metamorphic minerals and on the geological evidence, the second event is referred to the Tertiary Himalayan crystallization. Further petrological and geochronological studies are necessary to prove whether a few mineral relics ascribed to the first event define a polyphase Himalayan evolution or if they record the incomplete obliteration of an older history during the Himalayan event. The HHC of SE Zanskar show a decrease in metamorphic grade from the middle structural levels upward, close to the Kade unit, and downward, close to the Lesser Himalaya (from sillimanite-K-feldspar-biotite-bearing assemblages to kyanite-staurolite-muscovite-bearing assemblages). This metamorphic zonation is probably a consequence of the polyphase history of intracontinental thrusts and of the tectonic emplacement of hot crustal slabs within shallower and colder thrust sheets at relatively late stages of the continental collision between India and Eurasia. 相似文献
974.
Wang Andong Ren Yuhe Sun Wenfu Yu Longwei Liang Jingming Cao Tianqing Gu Haoding 《地震学报(英文版)》1988,1(4):60-72
We have obtained altogether heat flux data of 23 drill holes including 2 observational holes of thermal flow in the Haicheng
seismic area. These data show roughly thermal structure of the crust in eastern Liaoning and in the Haicheng seismic area.
The results indicate that there is higher value of heat flow in the belt north by east from Liaoyang to Xiongyue, the average
thermal flux being 8.29× 10−2J/m2·s (2.0 hfu). The average thermal fulx in the Haicheng seismic area is 9.22×102J/m2·s (2.2 hfu).
Comparing with other known geophysical data of the Haicheng seismic area, we give a geophysical section of comprehensive interpretation.
We suppose the low-velocity layer in the lower crust of the Haicheng seismic area is a result from intrusion of large-scale
uper mantle substance. High temperature and low velocity mean that the layer has the nature of plastic mechanics. The focal
region of the Haicheng earthquake is situated right in the upper part of that plastic layer. Obviously, this result is significant
for studying the seismogenic process of the Haicheng earthquake and other intra-plate earthquakes.
We attempt to emphasize that observation of heat flow is necessary for earthquake study.
Gu Haoding did the actual writing. 相似文献
975.
对空间飞行器的电磁波散射截面进行了计算。本文取八种入射频率、五个高度上的电子密度所对应的电磁波散射截面和电声波散射截面进行了计算。结果表明,在正常情况下散射增强范围比Chen在辐射研究中给出的范围要大些。本文还对超高频波段在一些特定区产生的散射增强,用电离层中某些尺寸的不均匀结构的影响给予初步解释。 相似文献
976.
本文介绍在怀柔60cm多通道太阳望远镜上运用斑点干涉像复原方法所取得的一些初步结果,对用短暴光方法(暴光时间不大于10毫秒)获得的一系列“冻结”大气后的目标像用斑点干涉像复原方法进行处理,即可获得消除了地球大气影响的目标复原像,斑点掩模法即为斑点干涉像复原方法的一种,我们用它对日面中心的宁静区米粒进行处理,复原出了分率不劣于0.〃5的白光米粒象。 相似文献
977.
简要介绍高密度电法在天津软土地基勘察中的应用情况。分析天津软土地基的特点及地球物理前提条件,用典型实例说明高密度电法可以探查城市地下管道、了解地层起伏、探查沟坑变化、探测地基土均匀性等。发现并揭示了天津地区视电阻率与地基土物理力学指标之间的相关规律。同时估计了高密度电法可能的应用范围。 相似文献
978.
979.
郑州市近50年高温闷热天气气候特征分析 总被引:2,自引:0,他引:2
利用郑州1951~2002年气温资料,统计了郑州市各级高温及闷热天气,并与邻近城市及“三大火炉”城市进行了对比分析。结果表明:自20世纪80年代初以来,郑州夏季平均气温演变呈增高趋势,增温幅度大于周边城市,尤其90年代以来高温闷热天气日明显增多,但闷热日数及闷热程度仍不及“三大火炉”城市。 相似文献
980.
The shoreline vegetation of Lake Nubia in Sudan was studied by means of morphological characteristics and functional traits of plants established-phase as published in literature reviews. The 57 species recorded in 83 sampling sites were classified according to 15 morphological traits into six Plant Functional Types (PFTs), using Two Way Indicator Species Analysis (TWINSPAN). Principal component analysis (PCA) was used to evaluate the homogeneity of these groups in terms of their traits. The resulting PFTs were related to the physicogeographical variables measured (soil texture, soil moisture, soil thickness and elevation) using canonical correspondence analysis (CCA). The ratios in occurrences of the functional types were calculated per each moisture segment, and can be used as an indicator of the shoreline dynamics. 相似文献