Leading Tropical Modes Associated with Interannual and Multidecadal Fluctuations in North Atlantic Hurricane Activity

Author:

Bell Gerald D.1,Chelliah Muthuvel1

Affiliation:

1. Climate Prediction Center, NOAA/NWS/NCEP, Washington, D.C

Abstract

Abstract Interannual and multidecadal extremes in Atlantic hurricane activity are shown to result from a coherent and interrelated set of atmospheric and oceanic conditions associated with three leading modes of climate variability in the Tropics. All three modes are related to fluctuations in tropical convection, with two representing the leading multidecadal modes of convective rainfall variability, and one representing the leading interannual mode (ENSO). The tropical multidecadal modes are shown to link known fluctuations in Atlantic hurricane activity, West African monsoon rainfall, and Atlantic sea surface temperatures, to the Tropics-wide climate variability. These modes also capture an east–west seesaw in anomalous convection between the West African monsoon region and the Amazon basin, which helps to account for the interhemispheric symmetry of the 200-hPa streamfunction anomalies across the Atlantic Ocean and Africa, the 200-hPa divergent wind anomalies, and both the structure and spatial scale of the low-level tropical wind anomalies, associated with multidecadal extremes in Atlantic hurricane activity. While there are many similarities between the 1950–69 and 1995–2004 periods of above-normal Atlantic hurricane activity, important differences in the tropical climate are also identified, which indicates that the above-normal activity since 1995 does not reflect an exact return to conditions seen during the 1950s–60s. In particular, the period 1950–69 shows a strong link to the leading tropical multidecadal mode (TMM), whereas the 1995–2002 period is associated with a sharp increase in amplitude of the second leading tropical multidecadal mode (TMM2). These differences include a very strong West African monsoon circulation and near-average sea surface temperatures across the central tropical Atlantic during 1950–69, compared with a modestly enhanced West African monsoon and exceptionally warm Atlantic sea surface temperatures during 1995–2004. It is shown that the ENSO teleconnections and impacts on Atlantic hurricane activity can be substantially masked or accentuated by the leading multidecadal modes. This leads to the important result that these modes provide a substantially more complete view of the climate control over Atlantic hurricane activity during individual seasons than is afforded by ENSO alone. This result applies to understanding differences in the “apparent” ENSO teleconnections not only between the above- and below-normal hurricane decades, but also between the two sets of above-normal hurricane decades.

Publisher

American Meteorological Society

Subject

Atmospheric Science

Reference55 articles.

1. The 2002 Atlantic hurricane season [in “State of the Climate in 2002”].;Bell;Bull. Amer. Meteor. Soc,2003

2. Climate Assessment for 1997.;Bell;Bull. Amer. Meteor. Soc,1998

3. Bell, G. D., and M.Chelliah, 1999: The African easterly jet and its link to Atlantic basin tropical cyclone activity and the global monsoon system. Proc. 23d Annual Climate Diagnostics Workshop, Miami, FL, NOAA/Climate Prediction Center, 215–218.

4. Climate Assessment for 1998.;Bell;Bull. Amer. Meteor. Soc,1999

5. Climate Assessment for 1999.;Bell;Bull. Amer. Meteor. Soc,2000

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