CASPII and the Canadian cyclones during the 1989–92 cold seasons

Abstract

The climazological characteristics of cyclogenesis and the associated storm tracks in the domain of 40-70 0N and 50-14oe W are studied for the four cold seasons of 1989-1992. It is found that surface cyclones affecting the Canadian terrizories originate mostly from the eastern slopes of the Rocky Mountains, the Atlantic coast of the United Siates (US.) and the eastern North Paciflc basin. The explosive deepening of these systems is shown to occur preferentially along the Atlantic coast of both Canada and the US. h is also found that regions of mosi frequent occurrence of cyclones include Baffin Island, the Davis Strait, the northern Great Lakes and northern Newfoundland. A more detailed examination of the Canadian Atlantic Storms Program Il (CASP 11) season of January-March 1992 shows an anomalously large number of rapid cyclogenesis events occurring in the Atlantic coastal region of Canada. This anomaly is fourni in association with a persistent large-scale region of an unusually cold air mass. RÉSUME On étudie les caractéristiques climatologiques de la cyclogénese et des trajectoires des tempêtes sur le secteur de 40-70"N et 50-140" O pour les quatres saisons froides de 1989 à 1992. On s'aperçoit que les cyclones de surface affectant le territoire canadien proviennent surtout des pentes est des Rocheuses, de la côte atlantique américaine et du bassin est du Pacifique Nord. Le creusement explosif de ces systèmes survient particulièrement le long des côtes atlantiques canadienne et américaine. On remarque aussi que les régions les plus touchées comprennent l'île de Baffin, le détroit de Davis, le nord des Grands Lacs et le nord de Terre-Neuve. Une observation plus détaillée de la saison janvier-mars 1992 du Programme canadien d'études des tempêtes de l'Atlantique (PCETA Il) montre un nombre anomale fort elevé de cyclogénèses rapides sur les régions côtières atlantiques canadiennes. Cette anomalie est en association avec une région de grande échelle de masses d'air froLd inhabituelles persistante.

Sensitivity of cyclone tracks to the initial moisture distribution: A moist potential vorticity perspective

“…These systems play important roles not only in the long-term balances of energy, momentum, and water vapor in the climate system, but also in the regional weather and climate through changes in regional temperature and precipitation extremes (Cao et al, 2001(Cao et al, , 2002. The North Atlantic-European and the North Pacific sectors are two typical regions in the Northern Hemisphere where weather and climate are significantly influenced by these synoptic-scale weather systems (Fraedrich et al, 1986;Gyakum et al, 1996). Despite the importance of these mobile cyclones in determining the large-and regional-scale weather and climate, our understanding of the fundamental processes leading to their development, maintenance, and termination is far from complete.…”

Nearshore sediment transport as influenced by changing sea ice, north shore of Prince Edward Island, Canada

“…In winter, the SGSL is subject to storms that frequently track along the coast from the south, although some come from the west associated with Arctic systems. Storms tracking from the south typically bring extreme winds from the northeast, which back through the north to strong to moderate strength from the northwest (Gyakum et al 1996;Manson et al 2002b;Parkes et al 2006). These storms are effective in advecting sea ice from open water into the study area (Chagnon 2002).…”

Explosive cyclogenesis in the northeastern part of the Atlantic Ocean

“…The wide range of literature [5,9,11,18] deals with the study of the explosive cyclone nature. Thus, it was obtained after the analysis of the large number of observations in [11,18] that, as a rule, the cold air carrying-out from the North American continent near the Gulf Stream precedes the explosive cyclogenesis in the western part of the North Atlantic.…”

“…The wide range of literature [5,9,11,18] deals with the study of the explosive cyclone nature. Thus, it was obtained after the analysis of the large number of observations in [11,18] that, as a rule, the cold air carrying-out from the North American continent near the Gulf Stream precedes the explosive cyclogenesis in the western part of the North Atlantic. These are the intensive fluxes of latent and sensible heat being formed during the carrying-out which favor the transformation of the usual cyclone into the explosive one [9] and they can also influence the atmospheric circulation over the whole North Atlantic [3].…”