erc-uptrop Repository

TROPOMI cloud-slicing and validation code

A library for applying the cloud-slicing technique to TROPOMI total columns to obtain upper tropospheric (450-180 hPa) mixing ratios of NO2. This includes a feasibility test of the technique using synthetic observations from GEOS-Chem, validation and quantification of bias corrections by comparing TROPOMI and Pandora total columns at high-altitide sites, application of cloud-slicing using either the FRESCO-S or ROCINN-CAL cloud products, and comparison of effective cloud fractions and cloud top pressures from the two cloud products.

Examples of use

Cloud-slice synthetic partial columns from GEOS-Chem over North America at 4x5 in boreal spring:

   python ut_no2_gc_test.py --gc_dir "path/to/geoschem/data"  --out_path "/path/to/output/file" --resolution 4x5 --season mam --region NA

Co-sample daily Pandora and TROPOMI total NO2 columns at Izana in the first week of May:

   python compare_tropomi_pandora.py --trop_dir "/path/to/tropomi/data" --pan_dir "/path/to/pandora/data" --out_dir "/path/to/output/dir" --start_date 01-05-2019 --end_date 07-05-2019 --apply_bias_correction True --no2_col Trop --pandora_site izana

Cloud-slice Jun-Aug TROPOMI partial NO2 columns using the FRESCO-S cloud product in boreal summer:

   python tropomi_ut_no2.py --trop_dir "/path/to/tropomi/data/folder/" --out_dir "/path/to/output/folder/" --cloud_product fresco --season jja

Obtain January mean FRESCO-S and ROCINN-CAL cloud top pressures and fractions at 1x1:

   python fresco_cld_err.py  --trop_dir "/path/to/tropomi/data/folder/" --out_dir "/path/to/output/folder/" --start_date 01-01-2019 --end_date 31-01-2019 --out_res 1x1 --dlr_cld_top height

For a more advanced example bash script that runs each script over a given date range, see tests/integration_test.sh in your Uptrop folder. See https://pages.github.io/erc-uptrop/docs/build/html/index.html?#scripts for detailed explanations of each function.

Documentation

Documentation is hosted at https://erc-uptrop.readthedocs.io/en/latest/

Sources and citations

Files copied from eam-group repo (https://github.com/eamarais/eam-group/tree/master/eloise/uptrop)

Citation where details of the method, and interpretation and visualization of the data is: E. A. Marais, J. F. Roberts, R. G. Ryan, H. Eskes, K. F. Boersma, S. Choi, J. Joiner, N. Abuhassan, A. Redondas, M. Grutter, A. Cede, L. Gomez, M. Navarro-Comas, New observations of NO2 in the upper troposphere from TROPOMI, Atmos. Meas. Tech., 14, 2389-2408, doi:10.5194/amt-14-2389-2021. Link to PDF: https://amt.copernicus.org/articles/14/2389/2021/amt-14-2389-2021.pdf.

ERC Starting Grant UpTrop (grant number 851854; https://cordis.europa.eu/project/id/851854) to address uncertainties in reactive nitrogen in the upper troposphere (https://maraisresearchgroup.co.uk/uptrop.html).

The repository includes python code and routines to apply cloud-slicing to partial columns of NO2 to obtain mixing ratios of NO2 in the upper tropposhepre. The routine that does this is cloud_slice_ut_no2.py.