The Study Of Characteristic Of Spectrum Width In Rainfall Using Next Generation Weather Radar's Data

spectrum widths, one of the three moments measured and displayed by the new generation weather surveillance radar, provide the observation to the average radial velocity of rain particles caused by shear, turbulence and sample velocity's accuracy. Due to tight relation between widths and velocity, studying spectrum widths would have indication significance for the better understanding of wind field, wind change and development of rainfall system. The study of the characteristics of distribution of spectrum width of snow and rainfall is presented using the Doppler weather radar data in HUHEHAOTE and CHIFENG in this paper. The first conclusions are listed below based on analyzing characteristics of various rainfall system and researching relations between spectrum width with reflectivity , Doppler velocity, distance and with rainfall system development:(1) There are big differences between spectrum width caused by ground target clutters and that caused by precipitation echo. The width caused by ground target clutter changed slightly, and is nearly zero or located in the zero area with some none-zero value. Compared with ground target clutter width value, the width caused by precipitation is higher, and changed frequently with the development of the rainfall system.(2) The distribution characteristics of spectrum width has distinct discrepancy in convective precipitation, stratum precipitation and snow, the average width value in convective precipitation is the biggest, about 2.5 m/s. the average width value in stratum precipitation is 2.1 m/s. the average width value in snow system shows lowest value, is 1.8m/s. there are obvious differences in vertical distribution of spectrum widths of various weather system.(3) Comparing the distribution characteristics of velocity and spectrum width in rain, it is found that there is a obvious relation between spectrum width and velocity, the higher is spectrum width, the higher velocity. During snowing, the spectrum width does not change coherently with the velocity, and it shows anomalistic variety trend.