Targeted Observations for Wind Ramps using Ensemble Sensitivity Analysis

This study applies ensemble sensitivity analysis (ESA) to several wind ramp events from the winter of 2011-2012. Ensemble sensitivity can manipulated to identify the location and type of additional observations that should most improve the forecast. Previous uses of ensemble sensitivity have related state variables at a single forecast time (called the response function) to variables in the initial state or at earlier forecast times. This work uses responses function that are not fixed in time, but are based on characteristics of the event such as the ramp slope, maximum wind speed and timing of the ramp in order to diagnose the how these features are impacted by additional observations. The use of multiple cases is used to identify horizontal and vertical regions of recurring observational targeting values relative to the event. Furthermore, using different response functions allows for the comparison of targeting regions for different ramp characteristics. The results can be used to optimize observational networks for improved predictability of wind ramps at a specific wind farm.