Jul 17, 2013

Trend Analysis with a New Global Record of Tropical Cyclone Intensity

James P. Kossin, Timothy L. Olander, Kenneth R. Knapp
Journal of Climate
  • States the historical global ‘‘best track’’ records of tropical cyclones extend back to the mid-nineteenth century in some regions, but formal analysis of these records is encumbered by temporal heterogeneities in the data
  • Holds this is particularly problematic when attempting to detect trends in tropical cyclone metrics that may be attributable to climate change
  • Applies a state-of-the-art automated algorithm to a globally homogenized satellite data record to create a more temporally consistent record of tropical cyclone intensity within the period 1982–2009
  • Utilizes this record to investigate the robustness of trends found in the best track data
  • Calculates the lifetime maximum intensity (LMI) achieved by each reported storm
  • Tests the frequency distribution of LMI for changes over this period
  • Applies a direct homogenization procedure in which post-1998 data are degraded to pre-1998 standards to address the unique issues in regions around the Indian Ocean, which result from a discontinuity introduced into the satellite data in 1998
  • Finds this additional homogenization step measurably reduces LMI trends, but the global trends in the LMI of the strongest storms remain positive, with amplitudes of around +1 m s-1 decade-1 and p value = 0.1
  • Finds regional trends, in m s-1 decade-1, vary from –2 (p = 0.03) in the western North Pacific, +1.7 (p = 0.06) in the south Indian Ocean, +2.5 (p = 0.09) in the South Pacific, to +8 (p < 0.001) in the North Atlantic