Abstract 085

Abstract ID: 085

Prediction and Predictability Studies with NASA’s GEOS-S2S Modeling and Assimilation System

Lead Author: Andrea Molod
NASA Global Modeling and Assimilation Office, United States of America

Keywords: Predictability


NASA’s Global Modeling and Assimilation Office has recently begun conducting a new series of
predictability studies using the suite of retrospective forecasts with the GEOS-S2S Version 2
and Version 3 modeling and assimilation systems.

One area of focus is the predictability gained from strong land-atmosphere coupling. Metrics for
the strength of land-atmosphere coupling are being computed, and the conditional forecast skill
under conditions of strong coupling is being evaluated. These conditions under which the land-atmosphere
coupling results in increased skill will eventually be used to derive forecast perturbation states designed
to take advantage of the increased predictability. Preliminary results of the skill gained during forecasts
of opportunity related to land-atmosphere coupling strength will be presented.

Another area of focus is the investigation of determining a smooth transition of predictability from weather
to subseasonal lead times and that from subseasonal to seasonal lead times. At present, the predictability is
assumed to abruptly transition between one lead and another, in an ad hoc manner. The large suite of
retrospective forecasts is being used to study the transitions and determine, with appropriate metrics,
how the predictability may vary with state or regime. Preliminary results from the transition between
weather and subseasonal time scales will be presented.