Title: Assimilation of Earth Rotation Parameters into an Atmosphere Model

Authors: Lisa Neef (GFZ German Research Centre for Geosciences)
Katja Matthes (GFZ German Research Centre for Geosciences, Free University Berlin)

Observations of Earth rotation parameters (i.e. anomalies in the length-of-day and the orientation of the rotational pole) have a achieved a high degree of precision in recent years due to the space-geodetic observation techniques. By exchange of angular momentum with the solid earth, the atmosphere is a primary source of excitation of these Earth Rotation Parameters (or ERPs). Therefore, ERPs represent an integral measure of atmospheric dynamics, and a source of information that is independent of standard meteorological observations. The question is whether and how we can use this integral quantity to inform atmosphere/climate models. Because the observations are integrals of the atmospheric state, and also connected to ocean dynamics and the continental hydrosphere, the data assimilation problem presents unusual challenges. Moreover, the relative constraint offered by these observations, and the added value relative to meteorological observations, has been found to depend strongly on the timescale considered. In this talk we will discuss theses and other lessons learned in implementing the assimilation of ERPs into the atmospheric component of the Community Earth System Model (CESM) using an Ensemble Kalman Filter.

GMAO Head: Michele Rienecker Global Modeling and Assimilation Office NASA Goddard Space Flight Center

Curator: Nikki Privé Last Updated: May 27 2011