ON THE STRUCTURE OF HURRICANES IN THE UPPER TROPOSPHERE AND LOWER STRATOSPHERE¹

Abstract

A synoptic study c 8 number of hurricanes at the time of landfall is described with particular re._rence t o the thermal and wind structure in the upper troposphere and lower stratosphere. It is shown that the low pressure core of the mature hurricane, before recurvature, extends not only throughout the troposphere but sometimes protrudes into the lower stratosphere up to about 27 km., the upper limit of this investigation. The upper core is found to be cold above 15 km. with temperatures occasionally 8"-10" C. below normal at the tropopause level. A peripheral ridge and a peripheral jet in the upper troposphere are dcscribed, and the possible role of thesc features, as well as of the cold core, in the hurricane mechanism is discussed. It is suggested that the cold core may be caused by forced ascent above the well-known warm core of the hurricane. It is also shown that a hurricane which has recurved and becomc embedded in the extratropical westerlies may not have an upper cold core and its structure closely corresponds to the classical model. Tentative schematic models of the distribution of temperature and height anomalies are indicated in the case of a mature hurricane before recurvature. A photographic mission into the eye of typhoon Ida in September 1958 by a U-2 aircraft revealed the spectacular features of the cloud structure in hurricanes up to a level of 65,000 ft. (19.8 km.) which were discussed by Fletcher, Smith, and Bundgaard [2]. A research probe into hurricane Ginny up to 21 km. was made by a U-2 aircraft on October 22, 1964, and was studied by Penn [Ill. The aircraf6 flew over the eye a t levels of 50 mb., 115 mb., and 200 mb., and made a descent into it to about 300 mb. Although the eye region was 5"-6OC. warmer than the distant environment below 220 mb., the horizontal gradient of temperature and ozone became very weak just above the cloud tops a t 190 mb. The upper troposphere over the storm appeared to be slightly colder than the coastal environment. Another U-2 probe made into hurricane Isbell in October 1964, was also studied by Penn [12] who found that the tropopause was inclined

Detailed Analysis of A Tropical Cyclone Simulated with a 13-Layer Model

“…In the 100-200 mb layer where motions are assumed to be adiabatic, a cooling occurs be cause of dry adiabatic ascending motions. Such a cooling in the lower stratosphere is observed in actual tropical cyclones (KOTESWARAM, 1967). Fig.…”

Influence of tropical cyclones on tropospheric ozone: possible implications

“…The eyewall and radius of maximum winds increase with height. The low-pressure core extended to the UTLS region and the horizontal pressure gradient decreased with height (Koteswaram, 1967). Mitra (1996) and Das (2009) reported the weakening of the tropopause during the passage of a tropical cyclone.…”

Effect of tropical cyclones on the tropical tropopause parameters observed using COSMIC GPS RO data

“…Studies include the thermal and dynamical structure of UTLS during TC (Koteswaram, 1967), horizontal and vertical structure of temperature in the cyclone (Waco, 1970), temperature and ozone variations in a hurricane (Penn, 1965), troposphere-stratosphere transport and dehydration in cyclones (Danielsen, 1993), UTLS structure during TCs using AIRS and MLS measurements (Ray and Rosenlof, 2007), RO bending angle anomalies during tropical cyclones (Biondi et al, 2011), thermal structure of intense convective clouds derived from GPS RO (Biondi et al, 2012), estimating the TC cloud top height and vertical temperature structure using GPS RO measurements (Biondi et al, 2013), and observations of temperature in the UTLS of tropical weather disturbances (Davis et al, 2014). Note that the above list is only indicative, not exhaustive.…”