CIMAS Researchers Focus on Oceanic Heat to Improve Hurricane Forecasting

Building on prior research conducted in the Atlantic Ocean that has shown that hurricane intensity forecasts are greatly improved when oceanic heat content (OHC) data are included in statistical prediction models, researchers at the Cooperative Institute of Marine and Atmospheric Science (CIMAS) at the University of Miami are now adapting this approach for use in the Eastern Pacific Ocean. OHC data allow researchers to characterize upper ocean thermal structures, primarily with regard to temperature and salinity levels, which have traditionally been regarded as playing only minor roles in hurricane intensification. However, a series of recent meteorological events where the sudden intensification of tropical cyclones occurred when their path passed over warm oceanic features now have scientists speculating that their role is more significant than previously thought. Employing several data-collection platforms, including the 3,000-strong ARGO global network of floats and the TAO mooring array in the equatorial Pacific Ocean deployed by NOAA’s Pacific Marine Environmental Laboratory, CIMAS researchers continue to work on improving OHC estimates to better identify those oceanic regimes where hurricanes are most likely change intensity. Plans are underway to expand the approach for global OHC coverage for use at other international forecast centers.

Background: Under the auspices of the United States Weather Research Program, the NOAA Office of Oceanic and Atmospheric Research developed the Joint Hurricane Testbed Program to facilitate transition of basic research to operations. This enabled the development of a publicly available database of OHC data – updated daily – for the Atlantic and Eastern Pacific Oceans (http://isotherm.rsmas.miami.edu/heat). As with the Atlantic OHC data product, the Eastern Pacific OHC product is undergoing further testing and refinement at NOAA’s Cooperative Institute for Research in the Atmosphere (CIRA). CIMAS conducts collaborative research with NOAA in oceanography, climate, air-sea interactions and exchanges, fisheries oceanography, and integrated ocean observing.

Significance: In many ocean areas, sea surface temperatures alone are not enough to provide sufficient information to assess the ocean’s influence on hurricane intensity (for example, in Hurricanes Katrina and Rita in 2005). CIMAS' research has shown that rapid intensification occurs over deep warm pockets associated with eddies which can be identified using radar altimeter products. The use of OHC measurements will lead to improved forecasts for land-falling hurricanes and thereby provide advanced warnings that ultimately save lives. The approach supports NOAA’s Mission Goal 3 to serve societal needs for weather and water information to understand air-sea interactions and exchanges.