The Climatologic Research Of Maximum Wind Radius And Precipitation In Tropical Cyclones

The change and forecast of tropical cyclone (TC) intension is one of leading problems in TCresearch society at home and abroad. The change of TC intensity is closely correlated with TC'sstructure, the main characters who describe TC structure are those: TC center pressure, radius ofmaximal wind, maximal wind. The climatological research of RWM is singularly found, which isthe first issue analyzed in this paper.Since either seasonal or annual forecast of regionaI precipitation is one of important parts inoperational work, it is significant to improve our scientific knowledge in region precipitationcontinuously. One of effective ways to achieve that is respectively analyzing TC precipitationreduced from the whole precipitation and non-TC precipitation. The research of regionalprecipitation by this way is rarely seen, which is the other part of the paper.The followings are preliminary results of the two issues brought above:Using the NECP four-time/day reanalysis data from 2000 to 2004 (the horizontal resolution of1°×1°lat./lon. grid), and Typhoon Year-book from 1961 to 1984 and Tropical CycloneYear-book from 1985 to 2004 published by China Meteorological Administration, and precipitationdata of 740 station in China from National Climate Center, the relations between the radius oftangent maximum wind (RMW)and TC intensity is analyzed with 53 tropical cyclonesover western North Pacific during 2000-2004. The results indicate that: (1) Thereis a reverse correlation between RMW and TC intensity on each pressure level. (2) During theperiods of TC landing, RMW increases fast, while the tangent maximum wind decreases, and at thesame time the warm structure of TC is replaced by wet structure. the work investigate TC precipitation which is caused by tropical cyclones in China usingobservational record from 1961-2000. The study analyzes distribution of TC frequencies andprecipitations, and aIso presents the effect of location, season on the above factors. The resultshows that 56% of the TC causing precipitation in China lands. The TC precipitation mainly occursalong the southeast coast of China, with the equivalent precipitation line almost parallel with thecoast. It decreases rapidly inside the land, and there is less TC precipitation in the north of LianYungang. The TC precipitation is remarkably higher than those in East China and North China,while the former is higher than the latter. The high value area of TC precipitation is consistent withthe landing area of TC. The range of TC precipitation increases northward from April to August anddecreases southward from September to November. The anual changes of the annual TCprecipitation of 6 provinces in the east of China are not synchronous, and their phases of moreprecipitation and less precipitation are different between each other.