A comparison of ensemble-transform Kalman-filter targeting guidance with ECMWF and NRL total-energy singular-vector guidance

Abstract

Ongoing adaptive observing programmes strive to improve short- and medium-range forecasts of winter weather over populated areas. Aircraft equipped with Global Positioning System (GPS) dropwindsondes are directed over ordinarily data-sparse regions (oceans) to collect observations to enhance the subsequent operational analysis-forecast cycle. Two objective techniques that have been used to identify optimal 'target regions' are the ensemble-transform Kalman filter (ET KF) and the singular-vector technique. The similarities and differences between targeting guidance based on the ET KF and total-energy singular vectors (TESVs) are assessed for ten cases during the North Pacific Experiment (NORP..