Upper panel shows time-averaged normalized frequency distribution. Diurnal variation of normalized frequency distribution of the (a) direction and (b) speed of motion vectors in D2 during the entire period. ‘X’ mark indicates maximum frequency, whiskers represent the median, first and third quartile.įig. Upper (right) panel shows normalized frequency distribution of speed (direction) of motion vectors. Normalized frequency distribution of the direction and speed of motion vectors in D2 during the entire period. Flow chart of the construction of valid motion vectors from GSN, SSP radar data.įig. Box symbols indicate the locations of radar.įig. Dashed circles represent 150 km ranges from GSN and SSP radar. The altitude above mean sea level is shaded. Topography and analysis domains (D1, D2, D3). The speed of motion in Lee side of the island is smaller than that of the windward side.įig. In addition, the direction of precipitation motion is highly variable in time in August. The highest frequency occurs in precipitation motion toward east-northeast with the speed of $15$ in August. Three-year summer season data (June~August, 2011~2013) from two radars (GSN, SSP) in Jeju are used to obtain echo motion vectors that are retrieved by Variational Echo Tracking (VET) method which is widely used in nowcasting. General characteristics of radar-based motions are analyzed for warm season precipitation over Jeju region. Therefore, understanding the general characteristics of these motion vectors is important to improve the performance of nowcasting. We estimate the echo motion vectors that are used to extrapolate the echo properly. Nowcasting algorithms using weather radar data are mostly based on extrapolating the radar echoes.
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