Study On The Three-dimensional Structure Of Typhoon Based On Cinradmosaic

In this paper, based on CinradMosaic, developed by the State Key Laboratory of Severe Weather of Chinese Academy of Meteorological Sciences, advantages and disadvantages between single weather radar and weather radar networks observing the typhoon were discussed; A available method was proposed to locate the center of typhoon; The structure characteristics were analysed based on composite reflectivity and echo top generated by CinradMosaic; Combined the three-dimensional grid reflectivity and a two-step variational method, proposed by prof. Qiu, Lan Zhou university, the three-dimensional wind structure of Goni was discussed.The main results were as follows:1) Single-radar data and radar networks data were compared with observing the typhoon of HUGUPIT, which demonstrated the advantages clearly that mosaic could mitigate various problems that caused by the geometry of radar beam such as data voids with the cone of silence above the radar and in regions below the lowest beam. Meanwhile we also noticed that mosaic products smoothed some small structure characteristics.2) A available method-correlation method by reflectivity was developed in this paper, which could locate typhoon center during landing period with high temporal resolution. Two typhoon cases, HAGUPIT and GONI had been chosen to examine the proposed algorithm. The result showed this method could locate the center of HAGUPIT during landing with good precision, absolute error within 15km, compared with central meteorological office of CMA. Owing to assuming conditions in the locating algorithm, we suggested that it might be a better way to consider the way of human-machine to locating the typhoon center in operations.3) A variable which could reflect the asymmetry of typhoon was proposed to discuss its characteristics during landing of HAGUPIT and results were that the azimuths in the directions of maximum asymmetry and quasi-symmetry based on composite reflectivity were counterclockwise, the azimuths based on echo top were clockwise.4) The result of Testing the horizontal wind retrieved by two-step variational method using multi-radar radial velocity after dealiasing showed the the accuracy of retrieval wind was acceptable. The main wind field characteristics of Goni were that within the radius of maximum wind(RMW),the mean tangential component of wind increased near linear according to the increasing of distance away from center of Goni at the height of 4km,quite nearly the famous Rankine vortex model proposed by Rankine in 1901, fitting the tangential wind velocity at the radius of RMW at the height of 4km, we obtain the sine function that means the tangential component of wind is unsymmetrical distribution with wavenumber of 1, the inflows do not flow into center of Goni at all azimuths at low level and on the up layer the outflows also do not flow out of the center of Goni in all directions.