Aug 6, 2013

Sensitivity of Limiting Hurricane Intensity to SST in the Atlantic from Observations and GCMs

  • States that a statistical model for the intensity of the strongest hurricanes has been developed and a new methodology introduced for estimating the sensitivity of the strongest hurricanes to changes in sea surface temperature
  • Here, the authors use this methodology on observed hurricanes and hurricanes generated from two global climate models (GCMs)
  • Finds that hurricanes over the North Atlantic Ocean during the period 1981–2010 show a sensitivity of 7.9 ± 1.19 m s−1 K−1 (standard error; SE) when over seas warmer than 25°C
  • Finds, in contrast, that hurricanes over the same region and period generated from the GFDL High Resolution Atmospheric Model (HiRAM) show a significantly lower sensitivity with the highest at 1.8 ± 0.42 m s−1 K−1 (SE)
  • Finds similar weaker sensitivity using hurricanes generated from the Florida State University Center for Ocean–Atmospheric Prediction Studies (FSU-COAPS) model with the highest at 2.9 ± 2.64 m s−1 K−1 (SE)
  • Finds that a statistical refinement of HiRAM-generated hurricane intensities heightens the sensitivity to a maximum of 6.9 ± 3.33 m s−1 K−1 (SE), but the increase is offset by additional uncertainty associated with the refinement
  • Results suggest that the caution that should be exercised when interpreting GCM scenarios of future hurricane intensity stems from the low sensitivity of limiting GCM-generated hurricane intensity to ocean temperature

Figure: Limiting hurricane intensity as a function of SST based on the National Hurricane Center (NHC) best track. The line is a weighted regression where the weights are proportional to the number of hurricanes in each grid. The slope of the line is 7.9 m s21K21 and represents the sensitivity of LI to SST. The 95% confidence band about this slope is shown in gray. The 80% uncertainty about the per grid LI estimates is shown by the vertical lines.