# Which Digital Elevation Model (DEM) for single-level parameters in the "CAMS global atmospheric composition forecasts" database?

**URL:** <https://forum.ecmwf.int/t/which-digital-elevation-model-dem-for-single-level-parameters-in-the-cams-global-atmospheric-composition-forecasts-database/1551>\
**Category:** CAMS - Datasets and Usage\
**Tags:** cams, cams\_global\_forecast\
**Created:** [14 January 2022 14:37 UTC](https://forum.ecmwf.int/t/which-digital-elevation-model-dem-for-single-level-parameters-in-the-cams-global-atmospheric-composition-forecasts-database/1551 "2022-01-14T14:37:27Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![Jason\_Champion-Legen](https://forum.ecmwf.int/letter_avatar_proxy/v4/letter/j/bc79bd/32.png) [@Jason\_Champion-Legen](https://forum.ecmwf.int/u/Jason_Champion-Legen)\
**Post date:** [14 January 2022 14:37 UTC](https://forum.ecmwf.int/t/which-digital-elevation-model-dem-for-single-level-parameters-in-the-cams-global-atmospheric-composition-forecasts-database/1551/1 "2022-01-14T14:37:27Z")

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Hello everyone,

I am interested in using several single-level parameters from the CAMS global atmospheric composition forecasts database, e.g., aerosol optical depth and typology, water vapor and ozone content. These data are available with a spatial resolution of 0.4° x 0.4°. I would like to locally correct the integrated values taking into account a Digital Elevation Model (DEM), which will probably be the Copernicus GLO30 DEM. My questions concern the initial elevation information:

- Are the integrated values given by the database computed for an altitude of 0 m?
- Are they computed for an average altitude on the 0.4° x 0.4° pixel? If so, can I find this value somewhere, or is it correct if I compute it myself?
- Is there anything else that I can do?

Thank you very much for your help,

Best regards,

Jason