LR-IFS

Compute Lidar Ratio (LR) based on ECMWF IFS forecasts.

Methodology:

• We get the IFS forecasts data of aerosol optical depth forecasts for the different chemical components.
• We get the IFS forecasts data of relative humidity.
• For each aerosol species, we calculate a LR weighted by the relative optical depth contribution for different RH values.
• The total LR is determined as the sum of the weighted LR of the different aerosols species.

Individual aerosol LR for the different species are based on

• Flentje et al., 2021, at 1064nm (RH dependent)
• Kim et al., 2018, at 532nm (ambient RH)

example

lr-ifs --date 2024-09-26

Fig 1: IFS LR - 2024-09-26 - 1064 nm

get started

1. clone repo

git clone https://github.com/AugustinMortier/lr-ifs.git

2. install

• via poetry

poetry install

• via pip/pipx

pip install .

Note

You can also install lr-ifs with this one liner:

pip install "git+ssh://git@github.com/AugustinMortier/lr-ifs.git"

how to use

Compute LR for the 2024-09-26

lr-ifs --date 2024-09-26

This will create into output_path (default: ./data/):

• {yyyy}/{mm}/lr_ifs-{yyyymmdd}.nc: netcdf file which contains the computed LR.
• {yyyy}/{mm}/lr_ifs-{yyyymmdd}.json (if aprofiles option enabled (default)): json file which contains, for each E-PROFILE station available and for the selected day, the corresponding IFS-LR.

limitations

• Due to OD definition, the computed LR is an averaged value over the whole atmospheric column.
• Only one value per day is computed at the moment and corresponds to 00:00:00Z.
• When applicable (1064nm), only the RH at the surface level is considered.