Hurricane synoptic surveillance using the Ensemble Transform Kalman Filter targeted observing strategy

Sharan Majumdar

RSMAS Division of Meteorology and Physical Oceanography
University of Miami


The Ensemble Transform Kalman Filter (ETKF) has been used operationally in annual Winter Storm Reconnaissance programs since 2001 to select deployments of aircraft-borne dropwindsondes over the northeast Pacific. While the applicability of the ETKF and its ability to predict forecast error variance reduction due to targeted observations has been demonstrated for targeting in the mid-latitudes, it has only recently been extended to the tropics. The current operational targeting strategy for synoptic surveillance around hurricanes (using the NOAA Gulfstream G-IV aircraft) is based on NCEP GFS ensemble spread. During 2004, ETKF maps of predicted forecast error variance reduction were computed and compared against maps of ensemble spread, and G-IV flight tracks were designed based on both strategies for Hurricanes Frances, Ivan and Jeanne. This new application and future goals of tropical cyclone targeting will be presented.