The new reanalysis project ERA-40
will cover the period from mid-1957 to 2001 including the
earlier ECMWF reanalysis ERA-15, 1979-1993.
The main objective is to promote
the use of global analyses of the state of the atmosphere,
land and surface conditions over the period.
The three dimensional variational
technique will be applied using the T159L60 version of the
Integrated Forecasting System to produce the analyses every
six hours. Analysis involves comprehensive use of satellite
data, starting from the early Vertical Temperature Profile
Radiometer data in 1972, then later including TOVS,
data. Cloud Motion Winds will be used from 1979 onwards.
ERA-40 products will also revitalize
the use of data from past field experiments such as the
1974 Atlantic Tropical Experiment of the Global Atmospheric
Research Program, GATE,
1979 FGGE, 1982 Alpine Experiment,
ALPEX and more recent 1992-1993 TOGA-COARE.
Most of the older observations for
ERA-40 have been made available by NCAR.
ERA-40 will provide a new potential
for studying longer term trends and fluctuations such as