%0 Journal Article
%T Interannual Variability of Northern Hemisphere Storm Tracks in Coarse-Gridded Datasets
%A Timothy Paul Eichler
%A Jon Gottschalck
%J Advances in Meteorology
%D 2013
%I Hindawi Publishing Corporation
%R 10.1155/2013/545463
%X Extratropical cyclones exert a large socioeconomic impact. It is therefore important to assess their interannual variability. We generate cyclone tracks from the National Center for Environmental Prediction¡¯s Reanalysis I and the European Centre for Medium Range Prediction ERA-40 reanalysis datasets. To investigate the interannual variability of cyclone tracks, we compare the effects of El Ni£¿o, the North Atlantic Oscillation (NAO), the Indian Ocean Dipole (IOD), and the Pacific North American Pattern (PNA) on cyclone tracks. Composite analysis shows similar results for the impacts of El Ni£¿o, NAO, and the PNA on NH storm tracks. Although it is encouraging, we also found regional differences when comparing reanalysis datasets. The results for the IOD suggested a wave-like alteration of cyclone frequency across the northern US/Canada possibly related to Rossby wave propagation. Partial correlation demonstrates that although El Ni£¿o affects cyclone frequency in the North Pacific and along the US east coast, its impact on the North Pacific is accomplished via the PNA. Similarly, the PNA¡¯s impact on US east coast storms is modulated via El Ni£¿o. In contrast, the impacts of the NAO extend as far west as the North Pacific and are not influenced by either the PNA or El Ni£¿o. 1. Introduction A key issue in assessing present and future climate is in examining the climatology, variability, and trends in the characteristics of extratropical cyclones. The history of cyclone tracks research has two preferred methods to define cyclones. The first is the Eulerian method, which uses band-passed 500£¿hPa height field and strongest wave activity to define a cyclone (Blackmon [1], Blackmon et al. [2], Wallace et al. [3]), Hoskins and Valdes [4], Chang and Fu [5], Chang [6], Rao et al. [7], C. S. Frederiksen and J. S. Frederiksen [8], and Nakamura and Shimpo [9]). In contrast, a Lagrangian approach tracks cyclones by utilizing diagnostics such as minimum sea-level pressure (MSLP) (Petterson [10], Klein [11], Mather et al. [12], Reitan [13], Zishka and Smith [14], Sanders and Gyakum [15], Whittaker and Horn [16], Lambert [17], Murray and Simmonds [18], Chen et al. [19], Hirsch et al. [20], Eichler and Higgins [21], Changnon et al. [22], and Tilinina et al. [23]) or 850£¿hPa vorticity (Hodges [24¨C27], Hoskins et al. [28], Mesquita et al. [29], and Hodges et al. [30]). Advantages and disadvantages of cyclone methodologies depend on the application of the research. For example, Hodges et al. [30] note that 850£¿hPa vorticity becomes quite noisy at high-resolution requiring a
%U http://www.hindawi.com/journals/amete/2013/545463/