1C.2
**Local environmental conditions related to seasonal hurricane activity in the NE Pacific Basin
Jennifer M. Collins, University College London, Dorking, Surrey, United Kingdom
The northeast Pacific is important to study for several reasons. It is the basin with the second highest annual number of hurricanes in the world (9.6 +/- 3.0 per year) and it exhibits large seasonal variability (intense hurricane numbers varying between 10 (1992) and 0 (1977). Despite this, our ability to identify the environmental factors influencing seasonal hurricane activity in the NE Pacific, has to date been poor compared to the Atlantic. In this statistical study we show that there are at least two regions in the NE Pacific which need to be examined separately. This important distinction between a western and an eastern region allows significant correlations to be found in the western region with various environmental parameters, which are not found in the eastern region. It is thus unsurprising that previous researchers have found few significant results in the NE Pacific since the whole basin total is dominated by the poorly correlated eastern region hurricanes. It is also shown that in the western region there is a strong significant trend of hurricanes with time of 0.6 per decade showing that over the period of 26 years there has been an increase of 1.6 hurricanes compared to a mean of 2 . Such a strong trend is absent in the eastern region. Attention then focuses upon the differences of the environmental parameters between the two regions, both in space and time, in order to physically explain these results.
Session 1C, Interannual Variations Of Tropical Cyclones (Parallel with Sessions 1A and 1B)
Tuesday, 23 May 2000, 10:15 AM-12:15 PM
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