HYSPLIT Forum: hysplitbbs.arl.noaa.gov

There is only detailed description for GDAS 1-deg weekly data on archive information page.

I need to know the detailed information of GDAS 0.5-deg daily data such as vertical distribution, Where can I get these information?

Thanks.

We will post some documentation later this week.

Please see these files at ftp://arlftp.arlhq.noaa.gov/archives/gdas0p5/
readme_gdas0p5_info.txt
readme_gdas0p5_missings.txt

barbara.stunder wrote:Please see these files at ftp://arlftp.arlhq.noaa.gov/archives/gdas0p5/
readme_gdas0p5_info.txt
readme_gdas0p5_missings.txt

I have an additional question. Are GDAS1 and GDAS0P5 data both converted from FNL data in 1-deg resolution? If not, which dataset are they converted from respectively?

Thanks!

barbara.stunder wrote:Please see these files at ftp://arlftp.arlhq.noaa.gov/archives/gdas0p5/
readme_gdas0p5_info.txt
readme_gdas0p5_missings.txt

By the way, when I generate trajetories with GDAS 0.5-deg data of 2011, it always shows a warning like this :

WARNING: metini - vertical velocity missing
switching to divergence method (kvel=5)

Do you have any idea about this? Is it a fatal warning or I can just neglect it?

NCEP is not creating FNL 1-degree data anymore. NCEP changed nomenclature from FNL to GDAS. Both ARL's GDAS1 and GDAS0p5 are post-processed from the same NCEP GDAS run.

ARL processes NCEP's "raw" GDAS output to create ARL's GDAS0P5.

NCEP processes GDAS output (1 degree grib files) to create the HYSPLIT/ARL "GDAS1" format files.

There is no vertical velocity field in the GDAS0P5 so HYSPLIT automatically calculates it from the divergence. The Warning message tells you this is happening. Warnings in general can be neglected.

barbara.stunder wrote:NCEP is not creating FNL 1-degree data anymore. NCEP changed nomenclature from FNL to GDAS. Both ARL's GDAS1 and GDAS0p5 are post-processed from the same NCEP GDAS run.

ARL processes NCEP's "raw" GDAS output to create ARL's GDAS0P5.

NCEP processes GDAS output (1 degree grib files) to create the HYSPLIT/ARL "GDAS1" format files.

Could you please give me a link to the raw GDAS data? Thanks!

The raw GDAS output is not posted to a public server.

barbara.stunder wrote:The raw GDAS output is not posted to a public server.

In that case, could you please give me a brief description of the raw GDAS data? I need to know the horizontal and vertical distribution of the dataset.

Thanks very much.