云水行 声声情

在今年立秋第一场大雨后，我听到了这张《云水行》。当第一曲“唱一段思想起……”的歌词传来，我心里就笃定，这肯定是一张用心做的唱片。一口气听完整张专辑，脑海画面不断，音乐入木三分，这是我近期听到从选曲、录音到演唱最为动人的一张唱片。

Earthquake dynamic response behavior of Xiangchong valley type tailings impoundment in Yunnan, China

Tailings impoundments can potentially collapse due to damage caused by earthquakes,which has frequently occurred around the world.This study takes the proposed valley type tailings impoundment in Yunnan as the research object to analyze the dynamic response behavior under earthquake action with both numerical simulation and physical model test(1:300).The results of both tests show that the dynamic response of the valley type tailings impoundment is characterized by"medium stiffness effect",in other words,in a certain range,the"softer"the unsaturated tailings sand is,the more energy it can dissipate,which leads the decrease of the value of the acceleration amplification factor.In addition,the peak acceleration of the monitoring points increases with the vertical elevation,which indicates that the"elevation amplification effect"exists in the tailings impoundment dynamic response.The middle part of the outer side of the raised embankment reacts more sensitive than the crest,which is similar to the slope dynamic response.The starter dam reacts sensitively under the earthquake excitation,which should be given more attention during the seismic design.The dynamic response rules reflected by the numerical simulation are consistent with the results monitored on the physical model test,although there are some differences between their values.The dynamic response rules of the valley type tailings impoundment can provide basis for the design of the similar projects in this region.

The Impact of the Eastward Propagation of Convective Systems over the Tibetan Plateau on the Southwest Vortex Formation in Summer

Based on the temperature of the black body (TBB),station observed and NCEP reanalysis data,the impacts of the eastward propagation of convective cloud systems over the Tibetan Plateau on the southwest vortex (SWV) formation that occurred at 1800 UTC on 29 June 2003 are analyzed by using the Zwack-Okossi (Z-O) equation to diagnose the thermal and dynamic processes.It is found that,in summer,severe convective activities often occur over the Tibetan Plateau due to the abundant supply of moisture.The convective cloud near the east edge of the plateau could move eastward with a shortwave trough in the westerly.The divergent center that is induced by latent heat release,which is associated with severe convective activities,moves out with the convective cloud and contributes to the low level decompression which is favorable for the formation of plateau edge cyclogenesis (PEC).The Z-O equation indicates that,in this case,the latent heat release and convergence are the two most important factors for SWV formation,which amounts to about 42% and 15% of the term TOTAL,respectively.It is implied that the thermal process effect was more important than the dynamic process during SWV formation.

THE STATISTICAL CHARACTERISTICS OF IMPACT OF THE WESTWARD-GOING TROPICAL CYCLONES ON RAINFALL IN YUNNAN PLATEAU

Using data available from the Retrieval System Based on Yearbooks of Tropical Cyclones over the Western North Pacific,NCEP/NCAR reanalysis daily data and observed precipitation data for 1959 to 2007 in Yunnan,a province located in a low-latitude plateau,this work analyzes the climatic characteristics and the corresponding large-scale circulation patterns related to the western North Pacific westward moving TCs(WMTCs).Its impacts on the rainfall in the Yunnan Plateau are studied.Results show that WMTCs happen almost every year,mainly from July to September.It shows a downward trend in decadal variation.Nearly the entire Yunnan area is affected by them but the eastern part experiences the most severe influences.Most of the WMTCs migrate from the South China Sea,primarily make landfall in Hainan and Guangdong and enter the Northern Bay.The tracks of these typhoons can be classified into five categories,in which the most significant impact results from those making landfall in Guangdong.All categories of the tropical cyclones can induce province-wide heavy rainfall in Yunnan.Super typhoons bring about the heaviest and most extensive rainfall over the low-latitude plateau while the associated circulation pattern is marked with a dominant 500 hPa meridional circulation at middle latitudes,an active monsoon depression and Intertropical Convection Zone(ITCZ) at low latitudes and a westward-located South Asia High at 100 hPa,which is favorable for tropical cyclones to travel westward.WMTCs tend to go westward into the interior part of China if the subtropical high extends its westernmost ridge point to the northeast of Yunnan,or expands its periphery anti-cyclonic circulation to the Tibetan Plateau,or merges with the Qinghai-Tibetan high.