On the violation of gradient wind balance at the top of tropical cyclones

The existence of physical solutions for the gradient wind balance is examined at the top of 12 simulated tropical cyclones. The pressure field at the top of these storms, which depends on the vertically integrated effect of the warm core and the near surface low, is found to violate the gradient wind balance—termed here as a state of nonbalance. Using a toy model, it is shown that slight changes in the relative location and relative widths of the warm core drastically increase the isobaric curvature at the upper level pressure maps leading to nonbalance. While idealized storms return to balance within several days, simulations of real‐world tropical cyclones retain a considerable degree of nonbalance throughout the model integration. Comparing mean and maximum values of different storms shows that peak nonbalance correlates with either peak intensity or intensification, implying the possible importance of nonbalance at upper levels for the near surface winds.

[1]  S. Aberson,et al.  REWRITING THE TROPICAL RECORD BOOKS The Extraordinary Intensification of Hurricane Patricia (2015) , 2017 .

[2]  K. Emanuel,et al.  The Role of Inner-Core Moisture in Tropical Cyclone Predictability and Practical Forecast Skill , 2017 .

[3]  Y. Weng,et al.  Advances in Convection-Permitting Tropical Cyclone Analysis and Prediction through EnKF Assimilation of Reconnaissance Aircraft Observations , 2016 .

[4]  K. Corbosiero,et al.  Revisiting trough interactions and tropical cyclone intensity change , 2016 .

[5]  D. Raymond,et al.  Balanced dynamics and convection in the tropical troposphere , 2015 .

[6]  Y. Cohen,et al.  Linear instability of warm core, constant potential vorticity, eddies in a two‐layer ocean , 2015 .

[7]  Fuqing Zhang,et al.  Predicting Hurricane Intensity and Associated Hazards: A Five-Year Real-Time Forecast Experiment with Assimilation of Airborne Doppler Radar Observations , 2015 .

[8]  Masaki Satoh,et al.  On the Warm Core of a Tropical Cyclone Formed near the Tropopause , 2015 .

[9]  Fuqing Zhang,et al.  The Warm-Core Structure of Hurricane Earl (2010) , 2014 .

[10]  S. Durden.  Observed Tropical Cyclone Eye Thermal Anomaly Profiles Extending above 300 hPa , 2013 .

[11]  Robert Atlas,et al.  Development and validation of a hurricane nature run using the joint OSSE nature run and the WRF model , 2013 .

[12]  Fuqing Zhang,et al.  Effects of Vertical Wind Shear on the Predictability of Tropical Cyclones , 2013 .

[13]  Da-Lin Zhang,et al.  On the Rapid Intensification of Hurricane Wilma (2005). Part II: Convective Bursts and the Upper-Level Warm Core , 2013 .

[14]  Daniel P. Stern,et al.  How Does the Eye Warm? Part I: A Potential Temperature Budget Analysis of an Idealized Tropical Cyclone , 2013 .

[15]  David S. Nolan,et al.  On the Height of the Warm Core in Tropical Cyclones , 2012 .

[16]  Daniel P. Stern,et al.  Revisiting the Relationship between Eyewall Contraction and Intensification , 2012 .

[17]  Kerry Emanuel,et al.  Self-Stratification of Tropical Cyclone Outflow. Part I: Implications for Storm Structure , 2011 .

[18]  T. Dunkerton,et al.  The Dynamics of Eye Formation and Maintenance in Axisymmetric Diabatic Vortices , 2009 .

[19]  Daniel P. Stern,et al.  Reexamining the vertical structure of tangential winds in tropical cyclones: Observations and theory , 2009 .

[20]  George H. Bryan,et al.  Evaluation of an Analytical Model for the Maximum Intensity of Tropical Cyclones , 2009 .

[21]  G. Powers,et al.  A Description of the Advanced Research WRF Version 3 , 2008 .

[22]  David S. Nolan,et al.  Tropical Cyclone Intensification from Asymmetric Convection: Energetics and Efficiency , 2007 .

[23]  Terry Hock,et al.  Warm Core Structure of Hurricane Erin Diagnosed from High Altitude Dropsondes during CAMEX-4 , 2006 .

[24]  Kristen L. Corbosiero,et al.  Tropical Cyclone Formation in a Sheared Environment: A Case Study , 2004 .

[25]  Mark DeMaria,et al.  Large-Scale Characteristics of Rapidly Intensifying Tropical Cyclones in the North Atlantic Basin , 2003 .

[26]  K. Emanuel.  Sensitivity of Tropical Cyclones to Surface Exchange Coefficients and a Revised Steady-State Model incorporating Eye Dynamics , 1995 .

[27]  J. Molinari,et al.  External Influences on Hurricane Intensity. Part III: Potential Vorticity Structure , 1995 .

[28]  W. J. Steenburgh,et al.  On the interpretation of geopotential height tendency equations , 1993 .

[29]  J. Fritsch,et al.  On Understanding Height Tendency , 1993 .

[30]  B. Farrell,et al.  Tropical Cyclone Formation , 1993 .

[31]  J. Molinari,et al.  External Influences on Hurricane Intensity. Part II: Vertical Structure and Response of the Hurricane Vortex , 1990 .

[32]  Hugh E. Willoughby,et al.  Gradient Balance in Tropical Cyclones , 1990 .

[33]  J. Molinari,et al.  External Influences on Hurricane Intensity. Part I: Outflow Layer Eddy Angular Momentum Fluxes. , 1989 .

[34]  Kerry Emanuel,et al.  An Air-Sea Interaction Theory for Tropical Cyclones. Part I: Steady-State Maintenance , 1986 .

[35]  Lloyd J. Shapiro,et al.  The Response of Balanced Hurricanes to Local Sources of Heat and Momentum , 1982 .

[36]  Katsuyuki V. Ooyama,et al.  Conceptual Evolution of the Theory and Modeling of the Tropical Cyclone , 1982 .

[37]  Roger K. Smith,et al.  Tropical Cyclone Eye Dynamics , 1980 .

[38]  K. Ooyama,et al.  Numerical Simulation of the Life Cycle of Tropical Cyclones , 1969 .

[39]  P. Koteswaram.  ON THE STRUCTURE OF HURRICANES IN THE UPPER TROPOSPHERE AND LOWER STRATOSPHERE , 1967 .

[40]  J. G. Charney,et al.  On the Growth of the Hurricane Depression , 1964 .

[41]  A. Eliassen.  Slow Thermally or Frictionally Controlled Meridional Circulation in a Circular Vortex , 1951 .