Verification region selection and data assimilation for adaptive sampling

Abstract

Adaptive or targeted observations supplement routine observations at a pre-specified targeting time. Adaptive observation locations are selected to supplement routine observations in an attempt to minimize the forecast error variance of a future target forecast within some predefined verification region (VR) at some predefined verification time. Ideally, the VR is placed in a location where unusually large forecast errors are likely. Here, we compare three methods of selecting VRs: a climatological method based on seasonal averages of forecast errors; an unconditioned method based on verification time ensemble spread; and a conditioned method based on an ensemble transform Kalman filter (ETK..