@article{0f9712bbc5414a82b09c3816bacb4225,
title = "On the violation of gradient wind balance at the top of tropical cyclones",
abstract = "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.",
author = "Yair Cohen and Nili Harnik and Eyal Heifetz and Nolan, {David S.} and Dandan Tao and Fuqing Zhang",
note = "Funding Information: The work was supported by the Israeli Science Foundation grant 1537/12. Part of the work was done during the sab batical of NH at Stockholm University, supported by a Rossby Visiting Fellowship from the International Meteorological Institute of Stockholm University. F.Z. and D.T. are partially supported by the Office of Naval Research (grant N000140910526) and the Hurricane and Severe Storm Sentinel (HS3) investigation under NASA{\textquoteright}s Earth Venture Program and NOAA{\textquoteright}s Hurricane Forecast Improvement Program (HFIP). D.N. is supported by NASA CloudSat Program through grant NNX16AP19G. We thank Yonghui Weng for performing the real- world TC simulations used in this study, and the Texas Advanced Computing Center (TACC) for the computing. The Hurricane Nature Run simulation was performed at the Center for Computing Sciences at the University of Miami. Useful comments from both T. Cronin and from another, anonymous, reviewer greatly contributed to the final form of this work. Publisher Copyright: {\textcopyright}2017. American Geophysical Union. All Rights Reserved.",
year = "2017",
month = aug,
day = "16",
doi = "10.1002/2017GL074552",
language = "English (US)",
volume = "44",
pages = "8017--8026",
journal = "Geophysical Research Letters",
issn = "0094-8276",
publisher = "American Geophysical Union",
number = "15",
}