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contributor authorSnyder, Andrew D.
contributor authorPu, Zhaoxia
contributor authorZhu, Yuejian
date accessioned2017-06-09T16:38:34Z
date available2017-06-09T16:38:34Z
date copyright2010/10/01
date issued2010
identifier issn0882-8156
identifier otherams-71455.pdf
identifier urihttp://onlinelibrary.yabesh.ir/handle/yetl/4213349
description abstractThis study evaluates the performance of the NCEP global ensemble forecast system in predicting the genesis and evolution of five named tropical cyclones and two unnamed nondeveloping tropical systems during the NASA African Monsoon Multidisciplinary Analyses (NAMMA) between August and September 2006. The overall probabilities of the ensemble forecasts of tropical cyclone genesis are verified relative to a genesis time defined to be the first designation of the tropical depression from the National Hurricane Center (NHC). Additional comparisons are also made with high-resolution deterministic forecasts from the NCEP Global Forecast System (GFS). It is found that the ensemble forecasts have high probabilities of genesis for the three strong storms that formed from African easterly waves, but failed to accurately predict the pregenesis phase of two weaker storms that formed farther west in the Atlantic Ocean. The overall accuracy for the genesis forecasts is above 50% for the ensemble forecasts initialized in the pregenesis phase. The forecast uncertainty decreases with the reduction of the forecast lead time. The probability of tropical cyclone genesis reaches nearly 90% and 100% for the ensemble forecasts initialized near and in the postgenesis phase, respectively. Significant improvements in the track forecasts are found in the ensemble forecasts initialized in the postgenesis phase, possibly because of the implementation of the NCEP storm relocation scheme, which provides an accurate initial storm position for all ensemble members. Even with coarser resolution (T126L28 for the ensemble versus T384L64 for the GFS), the overall performance of the ensemble in predicting tropical cyclone genesis is compatible with the high-resolution deterministic GFS. In addition, false alarm rates for nondeveloping waves were low in both the GFS and ensemble forecasts.
publisherAmerican Meteorological Society
titleTracking and Verification of East Atlantic Tropical Cyclone Genesis in the NCEP Global Ensemble: Case Studies during the NASA African Monsoon Multidisciplinary Analyses
typeJournal Paper
journal volume25
journal issue5
journal titleWeather and Forecasting
identifier doi10.1175/2010WAF2222332.1
journal fristpage1397
journal lastpage1411
treeWeather and Forecasting:;2010:;volume( 025 ):;issue: 005
contenttypeFulltext


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