Interbasin Differences in the Relationship between SST and Tropical Cyclone Intensification
- NOAA/Atlantic Oceanographic and Meteorological Laboratory, Miami, Florida
- Marine Sciences Laboratory, Pacific Northwest National Laboratory, Seattle, Washington
- Pacific Northwest National Laboratory, Richland, Washington
Sea surface temperature (SST) is one of the most important parameters for tropical cyclone (TC) intensification. In this paper, it is shown that the impact of SST on TC intensification varies considerably from basin to basin, with SST explaining less than 3% of the variance in TC intensification rates in the Atlantic, 10% in the western North Pacific, and 17% in the eastern Pacific. Two main factors are shown to be responsible for these inter-basin differences. First, variability of SST along TCs’ tracks is considerably lower in the Atlantic. This is due to smaller horizontal SST gradients in the Atlantic compared to the eastern Pacific and stronger damping of pre-storm SST’s contribution to TC intensification by the storm-induced cold SST wake in the Atlantic. The damping occurs because SST tends to vary in phase with TC-induced SST cooling: in the Gulf of Mexico and northwestern basin where SSTs are highest, TCs’ translation speeds are lowest and therefore their cold wakes are strongest. In addition to this SST effect, a second factor is that SST tends to vary out of phase with vertical wind shear and outflow temperature in the western Pacific, with high SST associated with weak wind shear and a cold upper troposphere. Lastly, this strengthens the relationship between SST and TC intensification more in the western Pacific than in the eastern Pacific or Atlantic. Combined, these factors explain why pre-storm SST is such a poor predictor of TC intensification in the Atlantic compared to the eastern and western North Pacific.
- Research Organization:
- Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Biological and Environmental Research (BER)
- Grant/Contract Number:
- AC05-76RL01830
- OSTI ID:
- 1427557
- Alternate ID(s):
- OSTI ID: 1488451
- Report Number(s):
- PNNL-SA-126415
- Journal Information:
- Monthly Weather Review, Journal Name: Monthly Weather Review Vol. 146 Journal Issue: 3; ISSN 0027-0644
- Publisher:
- American Meteorological SocietyCopyright Statement
- Country of Publication:
- United States
- Language:
- English
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