Evaluating Wind and Temperature Structure in Analyses and Forecasts for PSU Real-Time HFIP Simulations

In this study, we examine the radial and vertical structure of azimuthal mean tangential winds in both analyses and forecasts from the EnKF system used at PSU. We do this for real-time cases from 2008-2011, and for retrospective forecasts using the same system for 2004-2007. Systematic verifications are performed using the airborne pseudo-dual-Doppler radar “swath” and “profile” analyses from the Hurricane Research Division (HRD). Additionally, we evaluate the radial and vertical structure of temperature in the eye through comparisons to flight-level observations and to dropsonde profiles, respectively.

Variability in structure among ensemble members is examined, and we investigate whether or not members whose analyses agree more closely with the observations tend to produce more accurate forecasts. Further, we evaluate the degree to which analyses are improved by the assimilation of airborne Doppler radar data. In particular, we focus on the size of the RMW, and on its outward slope. Finally, we evaluate gradient balance in the analyses and forecasts, with the goal of determining the realism of the analyses and the degree to which updates from the assimilation of radar data can be maintained.