Research Summaries

Back Improving HWRF through a Simple Parameterization of Spatial Inhomogeneity of Surface Drag

Fiscal Year 2016
Division Graduate School of Engineering & Applied Science
Department Meteorology
Investigator(s) Montgomery, Michael T.
Sponsor National Oceanic & Atmospheric Administration (Other-Fed)
Summary Our recent studies of the sensitivity of tropical cyclone intensification to the surface drag coefficient in a three-dimensional model by Montgomery et al. and Smith et al. have been extended to include perturbations of the surface drag coefficient in one of four boundary-layer parameterization schemes: the bulk scheme, the Blackadar scheme, the MRF scheme, and the GaynSeaman scheme. The schemes were slightly modified to have the same drag coefficient formulation and the same constant exchange coefficients for sensible heat and moisture. Our work found that the intensification rate and mature intensity are essentially unaltered when the drag coefficient is perturbed randomly by variations of up to 60%. The results, in conjunction with an analysis of coherent drag coefficient variations for a moving vortex, question the notion that coupled wind-wave models are necessary to accurately forecast tropical cyclone intensification and mature intensity. Here we propose to extend the foregoing applied research to NOAA's HWRF modeling system (Gopalakrishnan et al., 2013). The research will be conducted in three phases. The first phase will use the idealized configuration of the HWRF model with its standard PBL parameterization (Gopalakrishnan et al., 2012). The idealized configuration of the model will be used to investigate the robustness of our previous result regarding the sensitivity to the intensification process to large variations in the surface drag coefficient. The second phase will be to use the findings from the first phase to develop a simplified air-sea interaction module for the drag coefficient in the HWRF system. Working with our NOAA collaborators, the third phase will conduct tests of this simplified system for operational configurations.
Keywords Hurricane Surface Drag Parameterization Surface Drag Variability Tropical Cyclone Typhoon
Publications Publications, theses (not shown) and data repositories will be added to the portal record when information is available in FAIRS and brought back to the portal
Data Publications, theses (not shown) and data repositories will be added to the portal record when information is available in FAIRS and brought back to the portal