- Air-sea interaction
- Air-land interaction
- Local responses
The ECMWF Re-analysis (ERA) Archive
contains global analyses and short range forecasts of all relevant
weather parameters obtained with an invariant and consistent data
assimilation system which is kept unchanged over the interval 1979-1993.
The full model resolution for ERA is Spectral T106, Gaussian N80
(approximately equivalent to latitude/longitude 1.125 degrees), with 31
hybrid model levels in the vertical , six of them below 850 hPa.
As in the NCEP reanalysis experiment, the
data base has been enhanced with data not available when operational
analyses were made (satellite data, ship and buoy observations , data
from special observation periods FGGE, Alpex ). A comprehensive
description is given in Gibson et. al. (1997).
Some questionable trends of increasing
precipitation over tropical ocean are visible in ERA. Another problem it
was identified beginning around 1986-87 when it was discovered that the
African ITCZ precipitation maximum shifts from north of the equator to a
position just to the south. Kalberg (1997) describes a discrepancy in
the precipitation and soil temperature and moisture in a limited area in
the western equatorial Amazonia affecting the first 8 year of ERA data
and stresses that detailed conclusions on the behaviour of the tropical
convergence, particularly over America, and its associated precipitation
patterns should be carefully drawn.