Quantitative Precipitation Estimation And Its Application Research Based On Doppler Radar Data

Precipitation as an important meteorological elements of agricultural production and flood control and disaster mitigation, plays an important role in the meteorological services, especially in the process of flood control and disaster relief, precipitation has become an important scientific basis for governments at all levels command for flood control and decision making. Therefore, the accurate and timely access to a certain area of a certain period of time of rainfall distribution and use of radar data timely assess the ground a certain area of a certain period of time precipitation, has the very vital significance in the early warning and forecast of the weather. Based on radar rainfall intensity values between measured and accordingly by optimization process, the Nan-yang on September 27, 2014-28, a Z value of stratiform clouds weather process and the corresponding part of the precipitation station by hour rainfall intensity value, studies the radar- automatic rain gauge combined the application of the quantitative estimates of precipitation method,the main results were as follows:(1) The optimization process using the whole data respectively, 25 d Bz segmented data, 35 dBz segmented data get Z-I relation, to estimate rainfall and the measured value of rainfall scatterplot, the regression estimates of precipitation is better than that of a typical slope whole optimization, section optimization is better than the overall optimization, 25 d Bz section optimization better than 35 dBz section optimization. In short 25 d Bz Z- I the closest relationship and the measured values;(2) The use of four kinds of Z- I inverse correlation coefficient of the rainfall and the measured values,the overall optimization is greater than the typical Z-I relation, section optimization is greater than the whole optimization, 25 dBz section optimization is greater than 35 dBz section optimization method;Inversion(3) in the period of rainfall, when the rainfall is less than 4 mm/h, the typical relationship between Z- I underestimated the value of rainfall, rainfall and the overall optimization and section optimization are overrated value, greater than 4 mm/h when four estimates are underestimating the value of rainfall, but is more close to the measured values compared with 25 d Bz section optimization;(4) From the RMSE analysis, the overall optimization of the root mean square error less than the root mean square error of typical Z-I relation, 35 dBz sectional optimization of root mean square error is less than the overall optimization, 25 dBz sectional optimization of the root mean square error of root mean square error is less than 35 d Bz section;(5) With four kinds of optimization method to estimate rainfall values and the measured rainfall value calculating the slope of regression, correlation coefficient, ratio and root mean square error, and compared with the total rainfall, scored 25 dBz subsection optimum fitting is best, 35 times dBz section, the overall optimization of again, typical Z = 200 I1. 6 the worst;(6) 25 dBz section optimization is used to establish relationship with Z- I, centroid tracking method isadopted to improve the short-term forecast, simple and easy to operate, for 20-30 dBz prediction is better than other numerical, 100-1000 km2 echo tracking effect is good in the little cloud, prediction error and is directly proportional to the time interval.The results of this paper can be used to estimate the precipitation distribution of nanyang area, can be in weather forecast warning play an important role, for the local government and drought relief command,artificial precipitation efficiency evaluation and quickly assess the influence of precipitation of nanyang crops, providing scientific basis.