Mike Chen, Department of Geological and Atmospheric Sciences, Iowa State University; Amanda Black Department of Geological and Atmospheric Sciences, Iowa State University


In 1980, Frederick Sanders and John Gyakum classified the maritime cold season rapidly deepening low pressure system as an explosive cyclone due in part to its intense “bombing” nature. Ever since this phenomenon has been discovered, there have been many, papers, books, and lectures covering the mysterious anomaly. Many scientists attribute the behavior of this weather anomaly to baroclinicity. Baroclinicity is most often conjuncted with vertical shear caused by horizontal temperature gradient leading to the thermal wind in the mean flow. Baroclinicity, coupled with the upper level trough will lead to cyclonic circulation, leading to further amplification of the aloft disturbance, which leads to further intensification. However, not all researchers agree with this theory and suggest that other mechanisms are the cause of this phenomenon. By manually tracking explosively developing low pressure systems through means of NCEP surface analysis charts and OPC products, we are able to determine the forcings behind the low. A key identifier in determining these forcings is whether or not they re-intensify after the initial cyclone decays, leaving behind a residual low that continues to propagate until it redevelops or dissipates entirely. This tells us that baroclinic instability is not involved here and that other forcings are the cause of this intensification. In this study 33 cases of explosive cyclogenesis were collected and analyzed, coming up with 2 cases of reintensification. A revival case and a dissipation case were compared in order to determine what exactly caused on case to dissipate and another to reintensify so long into its life.

Copyright Owner

Calvin A. Chaffin


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