Design And Optimization Of Verification Scheme In Public Rainstorm Forecast

It is necessary to test and evaluate the rainstorm forecast,and it is need to establish a top-down integrity of the forecast inspection business processes,to formulate a scientific and feasible method for quality inspection and evaluation.In order to satisfy the needs of the public for the accuracy in rainstorm forecast,and improve the method of calibration,in this paper,the method of rainstorm forecast test in our country is analyzed,and reference to the idea of fuzzy test,based on the principle of falling area neighborhood contrast and the principle of descending grade,the central meteorological station precipitation forecast products from 2013 to 2014 is tested.A new scheme for checking the accuracy in public rainstorm forecast is designed.The exponential attenuation function and the distance weight coefficient are introduced to carry out sensitivity analysis.The results show that:(1)The method of rainstorm forecast test in our country is analyzed,the empty and missing will be more frequently appear in northern area if using strict “point to point” method of TS score.The result is TS score is relatively low.Relative to the "point to point" one-to-one correspondence TS test method,the method of rainstorm warning signal using a certain degree of fuzzy test.The site selection is extended.The low score or 0 score caused by the larger deviation of prediction is avoided.Effective scoring is given,and the scope of the forecast test is expanded.(2)Five different scoring schemes were designed and tested by the principle of descending gradient,and different field radius range is analyzed.The descending gradient rainstorm scoring form is put forward,and a new inspection rule is designed.(3)The principle of descending gradient takes into account the correspondence between the forecast and the actual magnitude.It can also have score if there is an order of magnitude difference.The comparison principle of the falling zone neighborhood considers the deviation of the predicted position.It can also have score if there is a deviation of the actual occurrence.Compared with the TS score,this scheme can improve the accuracy of the rainstorm forecast to more than 60 points.The forecast effect is accurate and acceptable to the public,the forecast score will be relatively high,which is good for forecasters to do a good job of rainstorm warning,and it is favorable to improve the accuracy of early warning.(4)The exponential decay function is used to optimize the principle of descending gradient,which avoids the occurrence of fault and mutation in different order of magnitude.The greater the decay constant,the smaller the attenuation degree of the function,the larger the score will be.With the introduction of exponential decay function,the closer the prediction and the actual situation,the higher the score will be.At the same time,there is a good continuity in the different orders of magnitude prediction and the actual results.(5)The distance weight coefficient is introduced to optimize the comparison method of the falling area.The closer to the site,the higher the weight coefficient is,and it makes the score of this station increase accordingly.The introduction of the distance weighting coefficient can avoid the fact that the score of the remote station in the distance of 30 km can also be regarded as the higher score of the forecast site,which improves the rationality of the score.(6)The optimized formula of the public rainstorm forecast accuracy is obtained,which provides a new scoring strategy for the forecaster and the manager.The new scheme method is complementary to our existing rainstorm forecast verification scheme,it has a positive effect on the improvement of testing results and improved forecasting technology,it also has a positive effect on the improvement of rainstorm forecast accuracy and early warning ability.