MASSH

MApping SSH

Libraries

• scipy
• xarray
• matplotlib
• dask
• netcdf4

Examples

1. BFN-QG with SWOT & Nadir data

This example is taken from a SSH Mapping Data Challenge (2020a). It considers realistic simulated SWOT and Nadir observations extracted from a state-of-the-art high resolution ocean model NATL60. The example shows how to run a BFN-QG (Le Guillou et al., 2020) experiment to estimate high resolution gridded SSH.

Download the data

The data is hosted here with the following directory structure

. 
|-- dc_obs
|   |-- 2020a_SSH_mapping_NATL60_topex-poseidon_interleaved.nc
|   |-- 2020a_SSH_mapping_NATL60_nadir_swot.nc 
|   |-- 2020a_SSH_mapping_NATL60_karin_swot.nc
|   |-- 2020a_SSH_mapping_NATL60_jason1.nc
|   |-- 2020a_SSH_mapping_NATL60_geosat2.nc
|   |-- 2020a_SSH_mapping_NATL60_envisat.nc

|-- dc_ref
|   |-- NATL60-CJM165_GULFSTREAM_y****m**d**.1h_SSH.nc

To start out create a directory data_Example1

mkdir data_Example1

In this directory, download the observation dataset (dc_obs, 285M) using :

cd data_Example1
wget https://ige-meom-opendap.univ-grenoble-alpes.fr/thredds/fileServer/meomopendap/extract/ocean-data-challenges/dc_data1/dc_obs.tar.gz --no-check-certificate

the reference dataset (dc_ref, 11G) using (this step may take several minutes) :

wget https://ige-meom-opendap.univ-grenoble-alpes.fr/thredds/fileServer/meomopendap/extract/ocean-data-challenges/dc_data1/dc_ref.tar.gz --no-check-certificate

and the DUACS maps that will be used as boundary conditions

wget https://ige-meom-opendap.univ-grenoble-alpes.fr/thredds/fileServer/meomopendap/extract/ocean-data-challenges/dc_data1/dc_mapping/2020a_SSH_mapping_NATL60_DUACS_swot_en_j1_tpn_g2.nc --no-check-certificate

Then uncompress the files using tar -xvf <file>.tar.gz. You may also use ftp, rsync or curlto donwload the data.

Run the notebook

In mapping/example open the notebook Èxample1.ipynb, associated with the configuration file called config_Example1.py

2. 4Dvar-SW with (idealized) 2D SSH data

Download the data

mkdir data_Example2
cd data_Example2
wget https://ige-meom-opendap.univ-grenoble-alpes.fr/thredds/fileServer/meomopendap/extract/LeGuillou/data_BM-IT_idealized.tar.gz  --no-check-certificate
tar -xvf data_BM-IT_idealized.tar.gz

Run the notebook

In mapping/example open the notebook Èxample2.ipynb, associated with the configuration file called config_Example2.py