## Meteorology / ARL Data FTP / Archive

The ARL web server contains several meteorological model data sets already converted into a HYSPLIT compatible format on the public directories. Direct access via FTP to these data files is "hardwired" into the GUI. Only an email address is required for the password to access the server. The "FTP menu" is locked until the FTP process is completed, at which point a message box will appear indicating the file name that was just transferred.

The ARL analysis data archive consists of output from the Global Data Analysis System (GDAS) and the NAM Data Analysis System (NDAS - previously called EDAS) covering much of North America. Both data archives are available from 1997 in semi-monthly files (SM). The EDAS was saved at 80-km resolution every 3-h through 2003, and then at 40-km resolution (AWIPS 212 grid) starting in 2004. The GDAS (every 6-h) was saved on a hemispheric projection at 191-km resolution through the end of 2006. The new 1-degree and half-degree GDAS archive is available every three hours. See notes below for a more detailed discussion of each file.

- EDAS :: 80 km 3P (<=2003 SM 82 Mb) Semi-Monthly data files at three hour intervals on pressure surfaces
- EDAS :: 40 km 3P (>=2004 SM 600 Mb) Semi-Monthly data files at three hour intervals on pressure surfaces
- FNL.NH :: 191 km 6P (<=2006 SM 86 Mb) Semi-Monthly data files at six hour intervals on pressure surfaces, northern hemispheric polar stereographic projection
- FNL.SH :: 191 km 6P (<=2006 SM 86 Mb) Semi-Monthly data files at six hour intervals on pressure surfaces, southern hemispheric polar stereographic projection
- GDAS :: 1-deg 3P (>=2005 WK 600 Mb) Weekly files (W1=1-7; W2=8-14; W3=15-21; W4=22-28; W5=29-end) every three hours on pressure surfaces
- GDAS :: 0.5-deg 3S (>=2008 DA 468 Mb) Daily files every three hours on the native GFS hybrid sigma coordinate system
- NAM12 :: 12-km 3P (>=2007 DA 395 Mb) Composite archive 0 to +6 hour forecasts appended into daily files for the CONUS at three hour intervals on pressure surfaces
- NAMs :: 12 km 1S (>=2008 DA 994 Mb) Composite archive 0 to +6 hour forecasts appended into daily files for the CONUS at one hour intervals on sigma surfaces

From the GUI it is necessary to enter the year, month, and data file period. Semi-monthly files are designated by 001 (1st through the 15th) and 002 (16th through the end of the month). Weekly files by the week number and the two-digit day for the daily files. The file names are created automatically.

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