One-month forecast experiments - without anomaly boundary forcings.

Abstract

A series of one-month forecasts were carried out for 8 January cases, using a particular prediction model and prescribing climatological sea-surface temperature as the boundary condition. Each forecast is a stochastic prediction that consists of three individual integrations. These forecasts start with observed initial conditions derived from data sets of three meteorological centers. The forecast skill was assessed with respect to time means of variables based on the ensemble average of three forecasts. The circulation patterns of the three individual integrations tend to be similar to each other on the one-month time scale, implying that forecasts for the 10 day (or 20 day) means are not fully stochastic. The overall results indicate that the 10-day mean height prognoses resemble observations very well in the first 10 days, and then start to lose similarity to real states, and yet there is some recognizable skill in the last 10 days of the month. The main interests in this study are the feasibility of one-month forecasts, the adequacy of initial conditions produced by a particular data assimilation, and the growth of stochastic uncertainty.-from AuthorsGeophysical Fluid Dynamics Lab/NOAA, Princeton Univ, Princeton, NJ 08542, USA.