Short-term Trajectory Prediction Of Doppler Radar Echo Image

Doppler radar echo images have a variety of uses and wide applications in the field of weather forecasting.The radar image can directly reflect weather changes within a certain time and space range,it can deduce the movement trajectory of some extreme weather and allow meteorological workers to make accurate weather forecasts.The extrapolation of the radar echo image allows meteorological workers to make accurate weather forecasts.There is a difficult problem to accurately divide the echo area,analyze the characteristic movement of the echo block and track the movement trajectory of the echo block.Based on the existing radar echo image trajectory tracking and extrapolation method and foundation,this paper mainly completes the following work contents:1.According to the tracking of each level echo block in the time series of the center of mass' s movement,this paper proposes a hierarchical method for extracting and tracking echo blocks.By dividing each radar echo image in the radar echo image sequence into multiple hierarchical matrices,all the echo blocks in the hierarchical matrix are extracted according to the rules of connected regions and the features of each echo block are calculated.Secondly,the trajectory tracking of the echo blocks is realized by calculating the similarity between the echo blocks of the same level in two adjacent radar echo images,and the finally obtained trajectory is the centroid movement trajectory of the echo blocks of each level in the time sequence.This method can effectively track the movement trajectory of the center of mass of the echo blocks of each layer in the radar echo image sequence,and the synthesis or splitting of one layer of echo blocks does not affect the tracking of the echo blocks of other layers.2.Based on the centroid movement trajectory of all echo blocks obtained by tracking,this paper proposes a radar echo image extrapolation method based on short-term trajectory prediction of echo blocks.In the short-term trajectory prediction method,this article mainly uses the least square method of linear prediction and the semi-Lagrangian method of nonlinear prediction.Then,according to the predicted movement trajectory,the overall movement trajectory of the echo block is predicted at the next moment through the interpolation method,and finally the radar echo is extrapolated according to the predicted overall movement trajectory of the echo block.The effectiveness of the method is verified from the extrapolated result image and the extrapolated evaluation index,two kinds of short-term trajectory prediction methods can be used for radar echo image extrapolation.In the meteorological numerical evaluation index,the critical success index obtained by the method used in this paper is 0.21 higher than that of the single centroid method,0.1 higher than that of the crosscorrelation method.In addition,the false alarm rate is lower than that of the two methods,so it can improve the accuracy of weather forecasting.