Added ICON interpolator (to point locations)

[efmkoene]

This branch adds a tool to the tools folder, which can interpolate ICON output to point locations, using inverse distance weighted interpolation horizontally, and linear interpolation vertically. [*]

import sys
sys.path.insert(1, '/path/to/processing-chain/tools')
from ICON_to_point import ICON_to_point

longitudes = [15,13,14,15] # Self-explanatory: the longitude coordinate of the station
latitudes = [51,52,50,51] # Self-explanatory: the latitude coordinate of the station
asl = [0,1000,1200,0] # The true topographical height (above sea level, asl) of the station (only needed for mountain stations)
elev = [10,70,400,40] # The inlet height above the surface
strategy = ['ground', 'mountain', 'mountain', 'middle'] # Ground stations: model topography[i] + elev[i]; Mountain stations: asl[i] + elev[i]; middle: half ground and half mountain station approach

# Example 3: get two fields
ICON_to_point(longitude=longitudes, latitude=latitudes, station_ground_elevation=asl,
                            station_altitude_over_ground=elev,                            
                            ICON_field_path='/scratch/snx3000/ekoene/processing-chain/work/CTDAS_OCO2/2018010100_0_8664/icon/output_2018010100_opt/ICON-ART-UNSTR_2018-01-02T08:00:00.000.nc', 
                            ICON_grid_path='/scratch/snx3000/ekoene/icon_europe_DOM01.nc', 
                            interpolation_strategy=strategy, 
                            k = 4, field_name=['qv','temp'])

It can also be called from the command line (but with reduced performance, as only one lon/lat point can be interpolated at a time).

It relies on a relatively modern xarray version (I have 2023.7.0), but that is automatically the case with the way the current conda environment is set up anyhow.

From the review, I would mainly ask for a good descriptive word that makes the difference between station_ground_elevation and station_altitude_over_ground as clear as possible -- it probably isn't a 100% clear right now. This is what it should correspond to:

• for the Cabauw station in the Netherlands, we have that station_ground_elevation=0 (as that is the local topography) while station_altitude_over_ground=27 (as that is the inlet height over the ground)
• for the Jungfraujoch station in Switzerland, we have that station_ground_elevation=3580 (as that is the local topography) while station_altitude_over_ground=5 (as that is the inlet height over the ground)

[*] (As a curious sidenote, inverse distance weighted interpolation == linear interpolation when only 2 points are considered. So, really, it is using inverse distance weighing both horizontally and vertically).

[github-actions]

PR Preview Action v1.4.6
🚀 Deployed preview to https://C2SM.github.io/processing-chain/pr-preview/pr-58/
on branch gh-pages at 2024-02-05 09:10 UTC

[mjaehn]

@efmkoene Thanks for this PR! I will review this one and already set the base branch to v3.1-rc. Since here, just one file is added, there is no conflict.

[mjaehn]

Some minor comments

[efmkoene]

Hopefully it's up to scratch now!

[mjaehn]

launch jenkins