Dynamic Potential Intensity: An improved representation of the ocean's impact on tropical cyclones

• Main Authors: Balaguru, Karthik (Author), Foltz, Gregory R. (Author), Leung, L. Ruby (Author), Asaro, Eric D' (Author), Liu, Hailong (Author), Zedler, Sarah E. (Author), Emanuel, Kerry Andrew (Contributor)
• Other Authors: Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences (Contributor), Massachusetts Institute of Technology. Program in Atmospheres, Oceans, and Climate (Contributor), Emanuel, Kerry (Contributor)
• Format: Article
• Language: English
• Published: American Geophysical Union (AGU), 2017-06-01T17:37:46Z.
• Subjects: Article
• Online Access: Get fulltext

 To incorporate the effects of tropical cyclone (TC)-induced upper ocean mixing and sea surface temperature (SST) cooling on TC intensification, a vertical average of temperature down to a fixed depth was proposed as a replacement for SST within the framework of air-sea coupled Potential Intensity (PI). However, the depth to which TC-induced mixing penetrates may vary substantially with ocean stratification and storm state. To account for these effects, here we develop a "Dynamic Potential Intensity" (DPI) based on considerations of stratified fluid turbulence. For the Argo period 2004-2013 and the three major TC basins of the Northern Hemisphere, we show that the DPI explains 11-32% of the variance in TC intensification, compared to 0-16% using previous methods. The improvement obtained using the DPI is particularly large in the eastern Pacific where the thermocline is shallow and ocean stratification effects are strong.