摘要：This study investigated the impact of different verification-area designs on the sensitive areas identified using the conditional nonlinear optimal perturbation （CNOP） method for tropical cyclone targeted *** sensitive areas identified using the first singular vector （FSV） method,which is the linear approximation of CNOP,were also investigated for *** analyzing the validity of the sensitive areas,the proper design of a verification area was *** cyclone Rananim,which occurred in August 2004 in the northwest Pacific Ocean,was *** sets of verification areas were designed;one changed position,and the other changed both size and *** CNOP and its identified sensitive areas were found to be less sensitive to small variations of the verification areas than those of the FSV and its sensitive *** larger variations of the verification area,the CNOP and the FSV as well as their identified sensitive areas changed *** terms of reducing forecast errors in the verification area,the CNOP-identified sensitive areas were more beneficial than those identified using *** design of the verification area is important for cyclone *** verification area should be designed with a proper size according to the possible locations of the cyclone obtained from the ensemble forecast *** addition,the development trend of the cyclone analyzed from its dynamic mechanisms was another *** the general position of the verification area was determined,a small variation in size or position had little influence on the results of CNOP.

摘要：In order to compare the sensitivity of short-range ensemble forecasts to different land-surface parameters in the South China region,three perturbation experiments related to the land surface model(LSM),initial soil moisture(ISM),and land–atmosphere coupling coefficient(LCC)were designed,and another control experiment driven by the Global Ensemble Forecast System(GEFS)was also *** ensemble members were initiated at 0000 UTC each day,and integrated for 24 h for a total of 40 days from the period 1 April to 10 May 2019 based on the Weather Research and Forecasting *** results showed that the perturbation experiment of the LSM(LSMPE)had the largest ensemble spread,as well as the lowest ensemble-mean root-mean-square error among the three sets of land-surface perturbed experiments,which indicated that it could represent more uncertainty and less *** ensemble spread of the perturbation experiment of the ISM(ISMPE)was generally less than that of LSMPE but greater than that of LCCPE(the perturbation experiment of the LCC).In particular,although the perturbation of the LCC could not produce greater spread,it had an effective influence on the intensity of ***,the ensemble spread of all the land-surface perturbed experiments was smaller than that of GEFSPE(the control experiment).Therefore,in future,land-surface perturbations and atmospheric perturbations should be combined in the design of ensemble forecasting systems to make the model represent more uncertainties.