Observed Tropical Cyclone Eye Thermal Anomaly Profiles Extending above 300 hPa

Abstract

Abstract As recently pointed out by Stern and Nolan, much of our knowledge of the warm core structure of the tropical cyclone eye has come from composites of in situ data taken from multiple aircraft studies of three storms in the late 1950s and 1960s. Further observational confirmation of eye thermal structure has been lacking, since much of the dropsonde data analyzed to date have been limited to pressure levels of 500 hPa or lower. However, there exist a number of dropsonde eye profiles extending to near 250 hPa; these profiles were acquired from NASA aircraft during various field campaigns. Here, the author uses these data to calculate eye temperature anomaly profiles. These data are supplemented by several surface-based radiosonde releases in tropical cyclone eyes over the period 1944–2003. The author finds that the pressure altitude of the maximum anomaly varies between 760 and 250 hPa. The author also finds positive correlations between the maximum anomaly level and storm intensity, size, upper-level divergence, and environmental instability.