Towards Attribution of Hurricane Activity Changes
Abstract
We explore recent progress towards attributing observed tropical storm and hurricane activity changes in the Atlantic basin. We outline a strategy for regional climate change attribution that is relatively general, and discuss aspects of the hurricane attribution problem that make it particularly difficult to make strong attribution statements about, and recent efforts to do so. The general approach is a two part attribution, wherein an ultimate causal agent is connected to a proximate causal agent, and that proximate causal agent is connected to changes in hurricane activity. In order to attribute changes in hurricane activity, one must: i) define a measure of activity, ii) make efforts to correct historical estimates of this change in activity for data problems, iii) develop comprehensive dynamical models and theoretical understanding to connect changes in activity to large-scale environmental parameters. This methodology is applied to annual tropical storm (TS) counts in the Atlantic. In the observed record there is an unambiguous increase in TS counts over the past 25 years, but accounting for 'missed' storms the increase since the late-19th Century is not significant since late-19th. Using comprehensive dynamical models, it is found that the recent increase in Atlantic TS and hurricanes can be forced by observed sea surface temperature (SST) changes. In these models, it is found that the global-mean and tropical-mean SST changes were not the primary driver of changes in TS and hurricane frequency, and that the changes were driven by the pattern of SST change. Efforts are made to identify the most influential patterns of SST change, and connect these relevant patterns to forced and internal climate variations.
- Publication:
-
AGU Spring Meeting Abstracts
- Pub Date:
- May 2009
- Bibcode:
- 2009AGUSMGC22A..01V
- Keywords:
-
- 1637 Regional climate change;
- 3305 Climate change and variability (1616;
- 1635;
- 3309;
- 4215;
- 4513);
- 3374 Tropical meteorology;
- 4928 Global climate models (1626;
- 3337)