Processing of MetOp level1b dataset

[Salvatore Larosa]

Hello,

I successfully built an instance of AAPP (8.4) using a Singularity container (4.1.0) on CentOS 7. Everything was installed properly, and the test case reported here worked perfectly—great!

Now, I would like to process the MetOp level 1b data that I downloaded from the EUMETSAT Datastore. The datasets I downloaded are:

AMSA_xxx_1B_M03_20231001120122Z_20231001134026Z_N_O_20231001133657Z.bin
IASI_xxx_1C_M03_20231001115954Z_20231001133858Z_N_O_20231001133835Z.nat
MHSx_xxx_1B_M03_20231001120050Z_20231001133949Z_N_O_20231001133613Z.bin
AVHR_xxx_1B_M03_20231001120103Z_20231001134003Z_N_O_20231001133739Z.nat

The .bin files are in BUFR format, while the .nat files are in EPS Native format.

Following the instructions in the User Guide (paragraph on EPS level 1b/1c), I downloaded the AMSU and MHS files in BUFR format, while the IASI file is in EPS Native format. I understand that these files need to be converted into .l1c format.

My task is to collocate the radiance data from AMSU-A, MHS, and IASI onto the IASI grid to get a level 1d dataset. However, when I run the command:

AAPP_RUN_METOP -b -d <dir_level1c> -o <work_dir> -i "AMSU-A MHS IASI AVHRR" -g "IASI"

I get the following error message:

> 2025/01/10 16:03:51 localhost.localdomain 67721 AAPP_RUN_METOP INFO      : Working directory is /mnt/work
> 2025/01/10 16:03:51 localhost.localdomain 67721 AAPP_RUN_METOP INFO      : Input directory is /mnt/level1b
> 2025/01/10 16:03:51 localhost.localdomain 67721 AAPP_RUN_METOP 
> 2025/01/10 16:03:51 localhost.localdomain 67721 AAPP_RUN_METOP ERROR     : aman.l1b missing or empty
> 2025/01/10 16:03:51 localhost.localdomain 67721 AAPP_RUN_METOP 
AAPP_RUN_METOP ended: output in /mnt/level1

Am I missing any steps? Could you please provide some guidance?

Thank you!

Salvatore

• This topic was modified 1 week, 4 days ago by Salvatore Larosa.

[Nigel Atkinson]

Sorry, I didn’t see this message originally. The AAPP_RUN_METOP script is strictly for level 0 input. Instead you need to decode the BUFR files:

eccodes_decodebufr_1c -i AMSA_xxx_1B_M03_20231001120122Z_20231001134026Z_N_O_20231001133657Z.bin
eccodes_decodebufr_1c -i MHSx_xxx_1B_M03_20231001120050Z_20231001133949Z_N_O_20231001133613Z.bin

For IASI, you could have obtained BUFR files too, but we can work with the “.nat” files:

convert_iasi1c IASI_xxx_1C_M03_20231001115954Z_20231001133858Z_N_O_20231001133835Z.nat

Create links:

ln -s AMSA_xxx_1B_M03_20231001120122Z_20231001134026Z_N_O_20231001133657Z.l1c aman.l1c
ln -s MHSx_xxx_1B_M03_20231001120050Z_20231001133949Z_N_O_20231001133613Z.l1c ambn.l1c
ln -s IASI_xxx_1C_M03_20231001115954Z_20231001133858Z_N_O_20231001133835Z.nat.l1c iasi.l1c

Then it should be possible to run atovpp:

atovpp -i “AMSU-A MHS IASI” -g IASI

At least, I think it should work. These are full-orbit files; most near-real-time applications use direct broadcast data or 3-minute granules.

Nigel

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