Observational tests of hurricane intensity estimations using GPS radio occultations

Abstract

This study presents a novel approach to estimating the intensity of hurricanes using temperature profiles from Global Positioning System radio occultation (GPSRO) measurements. Previous research has shown that the temperature difference between the ocean surface and the eyewall outflow region defines hurricanes' thermodynamic efficiency, which is directly proportional to the storm's intensity. Outflow temperatures in the eyewall region of 27 hurricanes in 2004-2011 were obtained from GPSRO observations. These observations, along with ocean surface temperatures from NASA Modern Era-Retrospective Analysis for Research and Applications, made it possible to estimate hurricane intensities using a simplified hurricane model. Our preliminary results are quantitatively consistent with best-track values from the National Hurricane Center within 9.4%. As a by-product of our study, we present for the first time GPSRO vertical temperature profiles in the vicinity of the eyewall region of hurricanes, which we compared with collocated temperature profiles from the European Centre for Medium-Range Weather Forecasts Reanalysis Interim (ERA-Interim). Some of the GPSRO data sets reveal a double tropopause in the vicinity of the eyewall-a characteristic that we do not see in ERA-Interim. We conclude that GPSRO observations can be of supplementary assistance in augmenting existing data sets used in hurricane intensity estimation. GPSROs' cloud-penetrating capability and high vertical resolution can be useful in providing soundings in the area close to the eyewall region of hurricanes revealing detailed information about their thermal structure, potentially advancing our current knowledge of their dynamics, evolution, and physics.

Effect of rainpower on hurricane intensity

“…Values of are computed from the satellite data by using the relation, , with three additive terms: one for rain, one for graupel, and one for snow. For the vertical profile of the temperature in the eyewall, T e ( z ), we use T e ( z ) = T s −6.5 z , where z is measured in kilometers [ Vergados et al , ]. Values of V are obtained from the National Hurricane Center's extended best track database [ Demuth et al , ].…”

Characterization of thermal structure and conditions for overshooting of tropical and extratropical cyclones with GPS radio occultation

“…Wong and Emanuel (2007), Luo et al (2008) and Vergados et al (2013) demonstrated that there is a connection between the cloud top height and cloud top temperature with the intensity of the storm. Biondi et al (2012Biondi et al ( , 2013 showed a correlation between the cloud top altitude and the storm's thermal structure.…”

Signatures of Heavy Precipitation on the Thermodynamics of Clouds Seen From Satellite: Changes Observed in Temperature Lapse Rates and Missed by Weather Analyses

“…Second, given that the observed RO refractivity is higher than the weather model, the reliability of operational RO retrievals using the weather analyses temperatures is lower. Our ability to analyze the moist thermodynamics of precipitation from either weather model, as done in most of the available literature, or standard RO retrievals (e.g., Biondi et al, ; Biondi et al, ; Bonafoni & Biondi, ; Vergados et al, ) is lower and therefore one benefits from model‐independent validation. Those situations where weather models and RO differ are where RO soundings are most useful to identify and correct errors in the weather prediction models.…”