THE NWP MODEL
The fields provided here are products of NCEP's mesoscale numerical
weather prediction (NWP) model known as the Early Eta Model and its
associated 4-D data assimilation system, known as the EDAS
(for Eta Data Assimilation System).
The name "Eta" derives from the model's
vertical coordinate known as the "eta" or "step-mountain"
coordinate. Whereas the Eta forecast model generates forecast
fields out to 36 hours from initial states at 00Z and 12Z, the
EDAS generates eight 3-hourly initial states or analyses during
each 24-hour period, utilizing a vast set of observed data.
Together, the mesoscale Eta Forecast Model and the Eta
Data Assimilation System will be hereafter referred
to as the ETA/EDAS.
A good reference describing the Eta Model is the 1994 paper by
Tom Black of NCEP in Volume 9 of the AMS journal Weather and
Forecasting, pages 265-278.
Two other references describing the Eta/EDAS system are:
A list of extended references is given
- Rogers, E., T. L. Black, D. G. Deaven, G. J. DiMego, Q. Zhao,
M. Baldwin, N. W. Junker and Y. Lin, 1996: Changes to the operational
``Early'' Eta analysis/forecast system at the National Centers for
Environmental Prediction. Wea. Forecasting, 11, 391--413.
- Rogers, E., D. Deaven and G. J. DiMego, 1995: The regional analysis
system for the operational "early" Eta model: original 80-km
configuration and recent changes. Wea. Forecasting, 10, 810--825.