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Description: Monthly gridded NO2 (total and tropospheric) and H2O column (TCWV) data record provides long-term information about vertical column densities of nitrogen dioxide and water vapour in the atmosphere.

Type: Data record (TCDR)

Satellites and instruments: GOME-2/Metop-A and GOME-2/Metop-B

Algorithm version: Level 3 gridding algorithm version 1.0 (based on GDP 4.8 GOME-2 Level 2 products)

Time period: 02/2007 - 08/2017 (GOME-2/Metop-A) , 01/2013 - 08/2017 (GOME-2/Metop-B)

Theoretical basis: Level 3 gridding algorithm using area-weighted tessellation and cloud screening.

Processing: DLR produces gridded monthly averaged NO2 (total and tropospheric) and H2O column products based on the level 2 products generated with the GOME Data Processor (GDP) operational algorithm (only forward-scan pixels are used). The latest GDP 4.8 uses an optimised DOAS (Differential Optical Absorption Spectroscopy) algorithm to determine the trace gas slant column. The DOAS slant column fitting is followed by Air Mass Factor (AMF) conversions to generate vertical columns.

Units and spatial resolution: The total and tropospheric NO2 columns are given as densities (molecules/cm2). The spatial resolution is 0.25° x 0.25° (global coverage) and the temporal resolution is monthly (calendar). The H2O columns are given in kg/m2. The spatial resolution is 0.5° x 0.5° (global coverage) and the temporal resolution is monthly (calendar).

Validation: The level 3 GOME-2 NO2 product has been validated by Belgian Institute for Space Aeronomy (BIRA-IASB). The validation is based on an end-to-end approach, that has been developed to evaluate independently all critical components of the retrieval chain, using correlative observations performed by ground-based and satellite instruments. Visit BIRA NO2 validation page for further information. The level 3 GOME-2 H2O product has been validated by DLR and DWD using other satellite and ground-based TCWV observations.

Archiving and dissemination: The data record is archived at the DLR and available via data record access page.

File format: The data record is delivered in NetCDF-4 format, each file containing monthly averaged NO2 / H2O data including error estimates (one trace gas per file), and additional cloud parameters and surface properties data.


Image gallery

GOME-2 pages at DLR: WDC, ATMOS