Search Results
1. Introduction Unmanned aircraft systems (UAS) have emerged as an alternative method of collecting weather observations to improve understanding of the tropical cyclone (TC) environment and the accuracy of TC forecasts ( Braun et al. 2016 ; Cione et al. 2016 ), particularly in hazardous conditions where it is too dangerous to operate manned reconnaissance aircraft. The Global Hawk (GH) is one such aircraft that can fly for up to 24 h at an altitude of 60 000 ft (18 288 m) and was first
1. Introduction Unmanned aircraft systems (UAS) have emerged as an alternative method of collecting weather observations to improve understanding of the tropical cyclone (TC) environment and the accuracy of TC forecasts ( Braun et al. 2016 ; Cione et al. 2016 ), particularly in hazardous conditions where it is too dangerous to operate manned reconnaissance aircraft. The Global Hawk (GH) is one such aircraft that can fly for up to 24 h at an altitude of 60 000 ft (18 288 m) and was first
boundary layer dynamics in secondary eyewall formation a key point is the existence of supergradient winds prior to the presence of the secondary eyewall itself . While most secondary eyewall studies have been based on numerical evidence, some are based on observations. Remote sensing observational data of secondary eyewalls using various satellite microwave channels have resulted in useful knowledge of their frequency of occurrence around the world (e.g., Kuo et al. 2009 ; Yang et al. 2013 ). In
boundary layer dynamics in secondary eyewall formation a key point is the existence of supergradient winds prior to the presence of the secondary eyewall itself . While most secondary eyewall studies have been based on numerical evidence, some are based on observations. Remote sensing observational data of secondary eyewalls using various satellite microwave channels have resulted in useful knowledge of their frequency of occurrence around the world (e.g., Kuo et al. 2009 ; Yang et al. 2013 ). In
: Aircraft observations . J. Atmos. Sci. , 72 , 4237 – 4260 , doi: 10.1175/JAS-D-14-0366.1 . Kieper , M. , and H. Jiang , 2012 : Predicting tropical cyclone rapid intensification using the 37 GHz ring pattern identified from passive microwave measurements . Geophys. Res. Lett. , 39 , L13804 , doi: 10.1029/2012GL052115 . Kossin , J. P. , 2002 : Daily hurricane variability inferred from GOES infrared imagery . Mon. Wea. Rev. , 130 , 2260 – 2270 , doi: 10
: Aircraft observations . J. Atmos. Sci. , 72 , 4237 – 4260 , doi: 10.1175/JAS-D-14-0366.1 . Kieper , M. , and H. Jiang , 2012 : Predicting tropical cyclone rapid intensification using the 37 GHz ring pattern identified from passive microwave measurements . Geophys. Res. Lett. , 39 , L13804 , doi: 10.1029/2012GL052115 . Kossin , J. P. , 2002 : Daily hurricane variability inferred from GOES infrared imagery . Mon. Wea. Rev. , 130 , 2260 – 2270 , doi: 10
theoretical studies all indicate that the primary cause of eyewall asymmetries is a response to the environmental wind shear and resulting vertical tilt of the vortex (e.g., Jones 1995 ; Frank and Ritchie 1999 ; Reasor and Eastin 2012 ). When concentric eyewalls occur in a storm, observations also indicate an asymmetric distribution of convection within the secondary eyewall ( Hence and Houze 2011 ). However, the contribution of these asymmetries in the secondary eyewall evolution has yet to be
theoretical studies all indicate that the primary cause of eyewall asymmetries is a response to the environmental wind shear and resulting vertical tilt of the vortex (e.g., Jones 1995 ; Frank and Ritchie 1999 ; Reasor and Eastin 2012 ). When concentric eyewalls occur in a storm, observations also indicate an asymmetric distribution of convection within the secondary eyewall ( Hence and Houze 2011 ). However, the contribution of these asymmetries in the secondary eyewall evolution has yet to be
, additional HS3 and satellite observations, and a convection-permitting 60-member ensemble simulation. Hurricane Edouard was a named tropical cyclone from 11 to 19 September 2014 that remained over the open Atlantic Ocean throughout its lifetime ( Stewart 2014 ). The tropical wave that eventually became Edouard exited the African coast on 6 September. As the broad area of low pressure tracked westward, convection increased near the center of the surface low, causing the wave to be designated as a tropical
, additional HS3 and satellite observations, and a convection-permitting 60-member ensemble simulation. Hurricane Edouard was a named tropical cyclone from 11 to 19 September 2014 that remained over the open Atlantic Ocean throughout its lifetime ( Stewart 2014 ). The tropical wave that eventually became Edouard exited the African coast on 6 September. As the broad area of low pressure tracked westward, convection increased near the center of the surface low, causing the wave to be designated as a tropical
this period in terms of both track and intensity. The examination of this stage of Nadine’s lifetime also benefits from extensive observations taken during the National Aeronautics and Space Administration’s (NASA) Hurricane and Severe Storm Sentinel (HS3) mission, which are compared to the simulations in order to develop a better understanding of Nadine’s behavior. Nadine developed from a tropical wave that emerged from the African coast on 7 September ( Brown 2013 ). The disturbance was
this period in terms of both track and intensity. The examination of this stage of Nadine’s lifetime also benefits from extensive observations taken during the National Aeronautics and Space Administration’s (NASA) Hurricane and Severe Storm Sentinel (HS3) mission, which are compared to the simulations in order to develop a better understanding of Nadine’s behavior. Nadine developed from a tropical wave that emerged from the African coast on 7 September ( Brown 2013 ). The disturbance was
Sentinel Experiment (HS3; Braun et al. 2016 ). This unique sampling offers an opportunity to investigate the environmental-, vortex-, and convective-scale processes that govern tropical cyclone (TC) intensity change. Zawislak et al. (2016 , hereafter Part I) focused on Edouard’s vortex-scale thermodynamic changes, as revealed in high-altitude dropsonde observations from the Global Hawk, in relation to the precipitation evolution using data from infrared and passive microwave sensors. Part II
Sentinel Experiment (HS3; Braun et al. 2016 ). This unique sampling offers an opportunity to investigate the environmental-, vortex-, and convective-scale processes that govern tropical cyclone (TC) intensity change. Zawislak et al. (2016 , hereafter Part I) focused on Edouard’s vortex-scale thermodynamic changes, as revealed in high-altitude dropsonde observations from the Global Hawk, in relation to the precipitation evolution using data from infrared and passive microwave sensors. Part II
