engleski

Multivariate data assimilation in the tropics by using equatorial waves

This paper reports recent advances in understanding of dynamical aspects of the tropical data assimilation. In contrast with the mid-latitudes, there is no a well-defined approach for the tropical data assimilation in numerical weather prediction (NWP) community which has traditionally been concentrated on the mid-latitude analysis problem. In particular, the impact of the equatorial Rossby, inertio-gravity, and mixed Rossby-gravity waves on the tropical forecast-error covariances is difficult to quantify. Various tropical waves are characterized by different couplings between the mass field and the wind field. The average mixture of these waves, built into the background-error covariance matrix for data assimilation provides analysis increments which appear nearly univariate even though they result from the advanced multivariate assimilation methodology. This applies to both dry and moist idealized tropical systems as well as to a 4D-Var NWP assimilation system.

tropics; data assimilation; 4D-Var; multivariate relationships; equatorial waves; moist processes

S.I. - Special Issue: Data Assimilation and its Applications.