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The ETA Model was used to provide operational regional forecast guidance and basic meteorological data for the SAFARI project. The model outputs included in this data set are ASCII map images (0.5 degree) for each of 51 parameters at 12-hour intervals. Data are available for February-April and August-September 2000.

The National Centers for Environmental Prediction (NCEP) developed this step-mountain ETA coordinate model generally known as the ETA Model. This NCEP ETA data assimilation and prediction system (see Mesinger et al., 1988; Black, 1994) has been used by the South African Weather Bureau/Service (SAWS) to provide operational regional forecast guidance since November 1993. The SAWS ETA model is a hydrostatic model with a horizontal grid spacing of approximately 48 km and 38 vertical levels, with layer depths that range from 20 m in the planetary boundary layer to 2 km at 50 mb. There have been several major ETA Model upgrades at SAWS: in March 1996, August 1998, November 1999, and August 2001.

Data Citation:

Cite this data set as follows:

South African Weather Service (SAWS). 2004. SAFARI 2000 ETA Atmospheric Model Data, Wet and Dry Seasons 2000. Data set. Available on-line [] from Oak Ridge National Laboratory Distributed Active Archive Center, Oak Ridge, Tennessee, U.S.A. doi:10.3334/ORNLDAAC/723.


Mesinger, F., Z. I. Janjic, S. Nickovic, D. Gavrilov, and D. G. Deaven. 1988. The step-mountain coordinate: model description and performance for cases of alpine lee cyclogenesis and for a case of an Appalachian redevelopment. Mon. Wea. Rev., 116: 1493-1518.

Mesinger, F. 1984. A blocking technique for representation of mountains in atmospheric models. Riv. Meteor. Aeronaut., 44:195-202.

Black, T. 1994. The new NMC mesoscale ETA model: description and forecast examples. Wea. Forecasting, 9: 265-278.

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.

Data Format:

The data files contain a single ASCII map image (133 values per line by 79 lines, single-space delimited, 0.5 degree data) for each of 51 parameters, every 12 hours. The files are named using the following format:


For example, the file "eta_DPT-1000_20000201_00z.asc" is an ETA model run ("eta") for the variable "DPT-1000" (dew point temp at 1000 mb, see Parameter Table in companion document) on 2000-02-01 (February 1, 2000) at 00z (hour 0000 Zulu, or GMT).

The files are organized by month (wet season: Feb, Mar, Apr 2000 and dry season: Aug, Sep 2000). Within the month directory, there are ZIP files for the various parameter groups (see Parameter Table in companion document). Thus, an entire month of a parameter group is stored together in a single ZIP file.

Additional information about the ETA model and model data format is found in the companion file:

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