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作者机构:Helmholtz Zentrum Geesthacht Inst Coastal Res D-21502 Geesthacht Germany Univ Reading NERC Ctr Earth Observat NCEO Reading Berks England
出 版 物:《TELLUS SERIES A-DYNAMIC METEOROLOGY AND OCEANOGRAPHY》 (地球,A辑:动力气象学与海洋学)
年 卷 期:2012年第64卷第1期
页 面:1-11页
核心收录:
学科分类:07[理学] 0707[理学-海洋科学] 08[工学] 081501[工学-水文学及水资源] 0815[工学-水利工程] 0706[理学-大气科学]
基 金:China Scholarship Council (CSC) Institute for Coastal Research Helmholtz-Zentrum Geesthacht NERC [earth010005, earth010002, NE/G015708/1] Funding Source: UKRI
主 题:cyclone tracking algorithm polar lows spatial filter North Atlantic
摘 要:In this study, we compare two different cyclone-tracking algorithms to detect North Atlantic polar lows, which are very intense mesoscale cyclones. Both approaches include spatial filtering, detection, tracking and constraints specific to polar lows. The first method uses digital bandpass-filtered mean sea level pressure (MSLP) fieldsin the spatial range of 200-600 km and is especially designed for polar lows. The second method also uses a bandpass filter but is based on the discrete cosine transforms (DCT) and can be applied to MSLP and vorticity fields. The latter was originally designed for cyclones in general and has been adapted to polar lows for this study. Both algorithms are applied to the same regional climate model output fields from October 1993 to September 1995 produced from dynamical downscaling of the NCEP/NCAR reanalysis data. Comparisons between these two methods show that different filters lead to different numbers and locations of tracks. The DCT is more precise in scale separation than the digital filter and the results of this study suggest that it is more suited for the bandpass filtering of MSLP fields. The detection and tracking parts also influence the numbers of tracks although less critically. After a selection process that applies criteria to identify tracks of potential polar lows, differences between both methods are still visible though the major systems are identified in both.