Wednesday, 25 January 2012
Categorization and Spatial Analysis of Flooding Storms in New England and Atlantic Canada
Hall E (New Orleans Convention Center )
The synoptic causes of historical storms elevating stream flow rates at river gauges across New England and Atlantic Canada were categorized using an empirical scheme. Given the dates of annual maximum elevated stream flow rates over the past 70 years on average, for select river gauges, the associated storms were categorized on the synoptic scale based on storm type and the geographic proximity of the storm track. Once identified at each gauge site, data trends were analyzed relative to climate predictors (NAO, ENSO) as well as event characteristics (storm strength, time period). Findings indicate that Great Lakes-based storms tended to cause as many events as Coastal lows, opposing the common thought and reputation that Coastal lows most heavily influenced stream flow rates in the winter months. Additionally, Great Lakes-bases storms tended to be weaker events, while Coastal lows tended to be stronger. While the data confirm previous findings regarding ENSO, such as a notable increase in Coastal low frequency during ENSO + years, the findings led to a possible contradiction regarding NAO. In a contradiction to previous studies regarding the teleconnections of the NAO phase with Coastal lows, the findings of this study concluded that the relationship between Coastal lows and elevated stream flow rates may not be as direct as previously thought. Coastal lows did not exhibit a spatial shift relative to the blocking effects of the NAO+ phase. While a larger sample size could add to the significance of this result, further investigation of the relationship is warranted.
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