Sentinel-5p SO2 data processing¶
This chapter describes the tasks performed for processing Sentinel-5p SO2 data from the operational processing.
See also the chapter on the Sentinel-5p SO2-COBRA data processing.
Product description¶
The product guides can be found at:
-
L2__SO2___
,PUM-SO2
Product User Manual
Further product details on filters/validation can be found in (Fioletov et al., 2020) and (Theys et al., 2019).
Features:
The retrieval product is a column density (mol/m2), which will be treated by CSO as a profile with \(n_r=1\) layers:
\[\mathbf{y}_r\]The simulation of a retrieval product from a model state does not require an apriori profile, and should be computed from:
\[\mathbf{y}_s ~=~ \mathbf{A}\ \mathbf{V}\mathbf{G}\ \mathbf{x}\]where:
\(\mathbf{y}_s\) is the simulated retrieval (mol/m2) defined on \(n_r=1\) layers;
\(\mathbf{A}\) is the averaging kernel matrix with shape \((n_r,n_a)\); with \(n_a\) the number of a priori layers;
\(\mathbf{x}\) is the atmospheric state, which probably consists of a 3D array of SO2 concentrations;
operators \(\mathbf{G}\) and \(\mathbf{V}\) together compute a simulated profile at the \(n_a\) a priori layers from the state, using horizontal (\(\mathbf{G}\)) and vertical (\(\mathbf{V}\)) mappings; units should be the same as the retrieval product (mol/m2).
In case \(\mathbf{x}^{true}\) is the true atmoshperic state, the retrieval error is quantified by the retrieval error covariance \(\mathbf{R}\) (in this scalar product a variance):
\[\mathbf{y}_s ~-~ \mathbf{A}\ \mathbf{V}\mathbf{G}\ \mathbf{x}^{true} ~\sim~ \mathcal{N}\left(\mathbf{o},\mathbf{R}\right)\]The retrieval status and quality is indicated by the
qa_value
. The recommended minimum is 0.5, this excludes cloudy scenes and other problematic retrievals.
References¶
- Fioletov, V., McLinden, C. A., Griffin, D., Theys, N., Loyola, D. G., Hedelt, P., Krotkov, N. A., and Li, C.:Anthropogenic and volcanic point source SO2 emissions derived from TROPOMI on board Sentinel-5 Precursor: first results,Atmos. Chem. Phys., 20, 5591-5607, doi:10.5194/acp-20-5591-202, 2020.
- Theys, N., Hedelt, P., De Smedt, I. et al.Global monitoring of volcanic SO2 degassing with unprecedented resolution from TROPOMI onboard Sentinel-5 Precursor.Sci Rep 9, 2643 (2019). doi:10.1038/s41598-019-39279-y
Acknowledgements¶
We hereby thank D. Griffin and V. Fioletov for their valuable input.
CSO processing¶
(See Tutorial chapter for introduction to CSO scripts and configuration)
An example configuration of the CSO processing of the S5p/SO2 data is available via the following settings:
-
Top-level settings that configure the job-tree with various sub-tasks. This is a generic file that could be used for multiple S5 products, edit it to select the SO2 processing.
config/Copernicus/cso-user-settings.rc
User-specific settings such as the work directory.
config/Copernicus/cso-s5p-so2.rc
Specific settings for SO2 product.
Start the job-tree using:
./bin/cso config/Copernicus/cso.rc
Selected sub-steps in the processing are described below.
Inquire Sentinel-5p/SO2 archive¶
S5p/SO2 observations are available from the Copernicus DataSpace; see the cso_dataspace module module for a detailed description.
Data is available for different processing streams, each identified by a 4-character key:
NRTI
: Near real time, available with a day after observation;OFFL
: Offline, available within weeks after observations;RPRO
: re-processing of all previously made observations;
The portal provides data files created with different processor versions. It is therefore necessary to first inquire both archives to see which data is available where, and what the version numbers are.
The CSO_DataSpace_Inquire
class is available to inquire the
Copernicus DataSpace. The settings used by this class allow selection
on for example time range and intersection area.
The result is a csv file which with columns for keywords such as orbit number and processor version,
as well as the filename of the data and the url that should be used to actually download the data:
orbit;start_time;end_time;processing;collection;processor_version;filename;href
21497;2021-12-06 14:05:54;2021-12-06 15:47:24;OFFL;02;020301;S5P_OFFL_L2__SO2____20211206T140554_20211206T154724_21497_02_020301_20211208T043331.nc;https://zipper.dataspace.copernicus.eu/odata/v1/Products('d9d33ffa-9fe5-43cc-b5a1-b65c22e874ad')/$value
21852;2021-12-31 14:37:39;2021-12-31 16:19:09;OFFL;02;020301;S5P_OFFL_L2__SO2____20211231T143739_20211231T161909_21852_02_020301_20220102T064010.nc;https://zipper.dataspace.copernicus.eu/odata/v1/Products('ff5c922c-450c-43db-97e4-f46bdd55ffb2')/$value
:
See the section on File name convention in the Product User Manual for the meaning of all parts of the filename.
To visualize what is available from the various portals, the
CSO_Inquire_Plot
could be used to create an overview figure:

The jobtree configuration to inquire the portals and create the overview figure could look like:
! single step:
cso.s5p.so2.inquire.class : utopya.UtopyaJobStep
! two tasks:
cso.s5p.so2.inquire.tasks : table-dataspace plot
!~ inquire files available on DataSpace:
cso.s5p.so2.inquire.table-dataspace.class : cso.CSO_DataSpace_Inquire
cso.s5p.so2.inquire.table-dataspace.args : '${PWD}/config/Copernicus/cso-s5p-so2.rc', \
rcbase='cso.s5p.so2.inquire-table-dataspace'
!~ create plot of available versions:
cso.s5p.so2.inquire.plot.class : cso.CSO_Inquire_Plot
cso.s5p.so2.inquire.plot.args : '${PWD}/config/Copernicus/cso-s5p-so2.rc', \
rcbase='cso.s5p.so2.inquire-plot'
Conversion to CSO format¶
The ‘cso.s5p.so2.convert
’ task converts orbit files downloaded from a portal into a CSO format.
Files are downloaded from a portal if not present locally yet; eventually they are also removed after conversion to avoid that the portal is completely mirrored.
To save storage, only selected pixels are included in the converted files,
for example only those within some region or cloud free pixels.
The selection criteria are defined in the settings, and added
to the ‘history
’ attribute of the created files as reminder.
The work is done by the CSO_S5p_Convert
class,
which is initialized using the settings file:
! task initialization:
cso.s5p.so2.convert.class : cso.CSO_S5p_Convert
cso.s5p.so2.convert.args : '${PWD}/config/Copernicus/cso-s5p-so2.rc', rcbase='cso.s5p.so2.convert'
See the class documentation for the general configuration, below some specific choices are described. The example is based on the S5p SO2 file from which the header is available in:
Orbit file selection¶
Based on the inquiry the download and conversion could be limitted to files created with the most recent processor versions.
For the S5P files a useful property is also the collection number, a 2-digit number that defines a collection of files (or actually processor versions) that together form a contineous series. The collection number is extracted from the filename, and stored as a column of the listing file.
The following setting is used to select specific files from the archive based on the properities stored in the listing file:
! Provide ';' seperated list of to decide if a particular orbit file should be processed.
! If more than one file is available for a particular orbit (from "OFFL" and "RPRO" processing),
! the file with the first match will be used.
! The expressions should include templates '%{header}' for the column values.
! Example to select files from collection '03', preferably from processing 'RPRO' but otherwise from 'OFFL':
! (%{collection} == '03') and (%{processing} == 'RPRO') ; \
! (%{collection} == '03') and (%{processing} == 'OFFL')
!
cso.s5p.so2.convert.selection : (%{collection} == '03') and (%{processing} == 'RPRO') ; \
(%{collection} == '03') and (%{processing} == 'OFFL')
Pixel selection¶
The CSO_S5p_Convert
class calls the S5p_File.SelectPixels()
method
to create a pixel selection mask for the input file.
The selection is done using one or more filters.
First provide a list of filter names:
cso.s5p.so2.convert.filters : lons lats valid quality sza ground_pixel cloud_fraction
Then provide for each filter the the input variable to be used for testing,
as a path name in the input file.
The next settings is the type of filter to be used, see the S5p_File.SelectPixels()
for supported types,
and the other settings required by the type.
The following is an example of a selection on longitude:
cso.s5p.so2.convert.filter.lons.var : Geolocation Fields/Longitude
cso.s5p.so2.convert.filter.lons.type : minmax
cso.s5p.so2.convert.filter.lons.minmax : -30.0 45.0
cso.s5p.so2.convert.filter.lons.units : degrees_east
Extension to the product guide¶
Several publications report extended data criteria beyond the PUMs quality_flags that should be used to ensure data quality. Examples of such are the emission source detection paper by (Fioletov et al., 2020), and the volcanic SO2 monitoring paper by Theys et al., 2019. Both publications mention the poor quality of observations at the edges of TROPOMI observation swath as well as the reduced quality at high Solar Zenith Angles. The integration time of pixels toward the edge of the swath has been reduced to decrease the pixel size, however this also reduces the overall quality of the observation (SNR). Therefor we advise to only select the pixels with id’s 25-425, and for really strict cases only 50-400. Examples of both the edge pixels and SZA effects are shown in the figures below, with 2 figures from Fioletov et al., 2020 and an example for the SZA based on the CSO results.

Examples of retrieved SO2 columns, retrieval errors, and quality flags.¶
Furthermore, Fioletov et al., 2020 (Fig below) report large-scale biases in the current TROPOMI product, with TROPOMI showing significantly higher total columns, which can be expected to introduce a potential high bias throughout the domain. A solution advised by Fioletov et al is to remove the bias by comparing up- and down-wind values around an SO2 emissions source, but that will not be included in this algorithm.
Variable specification¶
The target file is created as an CSO_S5p_File
object.
It’s AddSelection
method is called with the input object as argument,
and this will copy the selected pixels for variables specified in the settings.
The variable specification starts with a list with variable names to be created in the target file:
cso.s5p.so2.convert.output.vars : longitude longitude_bounds \
latitude latitude_bounds \
track_longitude track_longitude_bounds \
track_latitude track_latitude_bounds \
time \
pressure kernel qa_value \
vcd vcd_errvar \
detection_flag cloud_fraction solar_zenith_angle ground_pixel
For each variable settings should be specified that describe the shape of the variable
and how it should be filled from the input.
See the AddSelection
description for all options,
here we show some examples.
The longitude
and latitude
variables are copied almost directly out of the source files,
the only change that is applied is the selection of pixels.
All original attributes are copied, except for the bound
attribite since that would
give warnings from the CF-compliance checker:
cso.s5p.so2.convert.output.var.longitude.dims : pixel
cso.s5p.so2.convert.output.var.longitude.from : PRODUCT/longitude
cso.s5p.so2.convert.output.var.longitude.attrs : { 'bounds' : None }
cso.s5p.so2.convert.output.var.latitude.dims : pixel
cso.s5p.so2.convert.output.var.latitude.from : PRODUCT/latitude
cso.s5p.so2.convert.output.var.latitude.attrs : { 'bounds' : None }
The pixel boundaries are necessary to know the exact footprint of a pixel,
which is for example used when averaging over a grid or simulation from a model.
These are available in the input files, but without a units
attribute as these
are implied by the pixel center coordinate; the conversion therefore requires that
units are defined explicitly.
For the longitude_bounds
a special processing is needed for pixels crossing the dateline,
as the original data simply uses longitudes modulo 360 degrees:
! corner longitudes; no units in file:
cso.s5p.so2.convert.output.var.longitude_bounds.dims : pixel corner
cso.s5p.so2.convert.output.var.longitude_bounds.from : PRODUCT/SUPPORT_DATA/GEOLOCATIONS/longitude_bounds
cso.s5p.so2.convert.output.var.longitude_bounds.units : degrees_east
! ensure that near dateline the corners form a convex region around center
! (with some points outside [-180,+180] if necessary)
cso.s5p.so2.convert.output.var.longitude_bounds.special : longitude_bounds
! corner latitudes, no units in file:
cso.s5p.so2.convert.output.var.latitude_bounds.dims : pixel corner
cso.s5p.so2.convert.output.var.latitude_bounds.from : PRODUCT/SUPPORT_DATA/GEOLOCATIONS/latitude_bounds
cso.s5p.so2.convert.output.var.latitude_bounds.units : degrees_north
Also the locations of the pixels in the original track are copied, since these are useful when creating plots. These cannot be copied directly but require special processing:
cso.s5p.so2.convert.output.var.track_longitude.dims : track_scan track_pixel
cso.s5p.so2.convert.output.var.track_longitude.special : track_longitude
cso.s5p.so2.convert.output.var.track_longitude.from : PRODUCT/longitude
cso.s5p.so2.convert.output.var.track_longitude.attrs : { 'bounds' : None }
cso.s5p.so2.convert.output.var.track_latitude.dims : track_scan track_pixel
cso.s5p.so2.convert.output.var.track_latitude.special : track_latitude
cso.s5p.so2.convert.output.var.track_latitude.from : PRODUCT/latitude
cso.s5p.so2.convert.output.var.track_latitude.attrs : { 'bounds' : None }
The observattion times are constructed from time steps relative to a reference time; this requires special processing too:
cso.s5p.so2.convert.output.var.time.dims : pixel
cso.s5p.so2.convert.output.var.time.special : time-delta
cso.s5p.so2.convert.output.var.time.tref : PRODUCT/time
cso.s5p.so2.convert.output.var.time.dt : PRODUCT/delta_time
The observed vertical column density could be copied directly.
The target shape is (pixel,retr)
where retr
is the number of layers in the retrieval product (1 in this case):
! vertical column density:
cso.s5p.so2.convert.output.var.vcd.dims : pixel retr
cso.s5p.so2.convert.output.var.vcd.from : PRODUCT/sulfurdioxide_total_vertical_column
In the converted files, the retrieval error is always expressed as a (co)variance matrix, to facilitate (future) conversion of profile products. In this example, it is filled from the square of the error standard deviation:
! error variance in vertical column density (after application of kernel),
! fill with single element 'covariance matrix', from square of standard error:
! use dims with different names to avoid that cf-checker complains:
cso.s5p.so2.convert.output.var.vcd_errvar.dims : pixel retr retr0
cso.s5p.so2.convert.output.var.vcd_errvar.special : square
cso.s5p.so2.convert.output.var.vcd_errvar.from : PRODUCT/sulfurdioxide_total_vertical_column_precision
!~ skip standard name, modifier "standard_error" is not valid anymore:
cso.s5p.so2.convert.output.var.vcd_errvar.attrs : { 'standard_name' : None }
The averaging kernel is applied on atmospheric layers, defined by pressure levels. In this product the pressure levels are defined using hybride-sigma-pressure coordinates, and this requires special processing:
! Convert from hybride coefficient bounds in (2,nlev) aray to 3D half level pressure:
cso.s5p.so2.convert.output.var.pressure.dims : pixel layeri
cso.s5p.so2.convert.output.var.pressure.special : hybounds_to_pressure
cso.s5p.so2.convert.output.var.pressure.sp : PRODUCT/SUPPORT_DATA/INPUT_DATA/surface_pressure
cso.s5p.so2.convert.output.var.pressure.hyab : PRODUCT/tm5_constant_a
cso.s5p.so2.convert.output.var.pressure.hybb : PRODUCT/tm5_constant_b
cso.s5p.so2.convert.output.var.pressure.units : Pa
Averaging kernels are converted to matrices with shape (layer,retr)
:
! description:
cso.s5p.so2.convert.output.var.kernel.dims : pixel layer retr
cso.s5p.so2.convert.output.var.kernel.from : PRODUCT/SUPPORT_DATA/DETAILED_RESULTS/averaging_kernel
Other variables can be copied directly:
! quality flag:
cso.s5p.so2.convert.output.var.qa_value.dims : pixel
cso.s5p.so2.convert.output.var.qa_value.from : PRODUCT/qa_value
!~ skip some attributes, cf-checker complains ...
cso.s5p.so2.convert.output.var.qa_value.attrs : { 'valid_min' : None, 'valid_max' : None }
! cloud property:
cso.s5p.so2.convert.output.var.cloud_fraction.dims : pixel
cso.s5p.so2.convert.output.var.cloud_fraction.from : PRODUCT/SUPPORT_DATA/INPUT_DATA/cloud_fraction_crb
cso.s5p.so2.convert.output.var.cloud_fraction.attrs : { 'coordinates' : None, 'source' : None }
! detection flag, for observations near known source locations:
cso.s5p.so2.convert.output.var.detection_flag.dims : pixel
cso.s5p.so2.convert.output.var.detection_flag.from : PRODUCT/SUPPORT_DATA/DETAILED_RESULTS/sulfurdioxide_detection_flag
cso.s5p.so2.convert.output.var.detection_flag.attrs : { 'coordinates' : None }
cso.s5p.so2.convert.output.var.detection_flag.dtype : i1
Output files¶
The name of the target files should be specified with a directory and filename; the later could include a template for the orbit number:
! output directory and filename:
! - times are taken from mid of selection, rounded to hours
! - use '%{orbit}' for orbit number
cso.s5p.so2.convert.output.filename : /Scratch/CSO-data/Europe/S5p/SO2/C03/%Y/%m/S5p_SO2_%{orbit}.nc
A flag is read to decide if existing files should be renewed or kept:
cso.s5p.so2.convert.renew : True
The target file is created as an CSO_S5p_File
object.
It’s AddSelection
method is called with the input object as argument,
and this will copy the selected pixels for variables specified in the settings.
The Write
method creates the file.
Global attributes for the target file should be specified with:
! global attributes:
cso.s5p.so2.convert.output.attrs : format Conventions author institution email
!
cso.s5p.so2.convert.output.attr.format : 1.0
cso.s5p.so2.convert.output.attr.Conventions : CF-1.7
cso.s5p.so2.convert.output.attr.author : Your Name
cso.s5p.so2.convert.output.attr.institution : CSO
cso.s5p.so2.convert.output.attr.email : Your.Name@cso.org
Listing file¶
A listing file contains the names of the converted orbit files, and the time range of pixels in the file:
filename ;start_time ;end_time ;orbit
2018/06/S5p_RPRO_SO2_03272.nc;2018-06-01T01:32:46.673000000;2018-06-01T01:36:12.948000000;03272
2018/06/S5p_RPRO_SO2_03273.nc;2018-06-01T03:12:53.649000000;2018-06-01T03:17:43.082000000;03273
2018/06/S5p_RPRO_SO2_03274.nc;2018-06-01T04:52:43.586000000;2018-06-01T04:59:12.377000000;03274
:
This file will be used by the observation operator to selects orbits with pixels valid for a desired time range.
A listing file is for example created using the CSO_S5p_Listing
class.
In the settings passed to the class, define the name of the file to be created:
! csv file that will hold records per file with:
! - timerange of pixels in file
! - orbit number
<rcbase>.file : /Scratch/CSO/S5p/listing-SO2-Europe.csv
An existing listing files is not replaced, unless the following flag is set:
! renew table?
<rcbase>.renew : True
Orbit files are searched within a timerange:
<rcbase>.timerange.start : 2018-06-01 00:00
<rcbase>.timerange.end : 2018-06-03 23:59
Specify filename filters to search for orbit files; the patterns are relative to the basedir of the listing file, and might contain templates for the time values. Multiple patterns could be defined; if for a certain orbit number more than one file is found, the first match is used. This could be explored to create a listing that combines reprocessed data with near-real-time data:
<rcbase>.patterns : CO3/%Y/%m/S5p_*.nc
Catalogue¶
The CSO_Catalogue
class could be used
to create a catalogue of images for the converted files.
Configuration could look like:
! catalogue creation task:
cso.s5p.so2.catalogue.task.figs.class : cso.CSO_Catalogue
cso.s5p.so2.catalogue.task.figs.args : '${PWD}/config/Copernicus/cso-s5p-so2.rc', \
rcbase='cso.s5p.so2.catalogue'
The configuration describes where to find a listing file with orbits,
which variables should be plot, the colorbar properties, etc.
See CSO_Catalogue
class description for how
the settings in general look like.
The class creates figures for a list of variables:
! variables to be plotted:
cso.s5p.so2.catalogue.vars : vcd vcd_errvar qa_value \
cloud_fraction cloud_radiance_fraction
By default the catalogue creator simply creates a map with the value of the a variable on the track. Optionally settings could be used to specifiy a different unit, or the value range for the colorbar:
! convert units:
cso.s5p.so2.catalogue.var.vcd.units : umol/m2
! style:
cso.s5p.so2.catalogue.var.vcd.vmin : 0.0
cso.s5p.so2.catalogue.var.vcd.vmax : 100.0
Figures are saved to files with the basename of the original orbit file and the plotted variable:
/Scratch/CSO/catalogue/2018/06/01/S5p_RPRO_SO2_03278__vcd.png
S5p_RPRO_SO2_03278__qa_value.png
:

To search for interesting features in the data,
the Indexer
class could be used to create index pages.
Configuration could look like:
! index creation task:
cso.s5p.so2.catalogue.task.index.class : utopya.Indexer
cso.s5p.so2.catalogue.task.index.args : '${PWD}/config/Copernicus/cso-s5p-so2.rc', \
rcbase='cso.s5p.so2.catalogue-index'
When succesful, the index creator displays an url that could be loaded in a browser:
Browse to:
file:///Scratch/CSO/catalogue/index.html

Configuration of observation operator¶
The observation operator described in chapter ‘Observation operator’ requires settings from an rcfile.
First specify the (relative) location of the listing file with orbit file names and time ranges:
! template for listing with converted files:
<rcbase>.listing : ../S5p/RPRO/SO2/CAMS/listing.csv
The S5p data contains data defined on orbit tracks, this should be read from the files:
! also read info on original track (T|F)?
! if enabled, this will be stored in the output too:
<rcbase>.with_track : T
The operator should read variables from the data files that are needed to simulate a retrieval from the model arrays. This includes for example the pressures that define the a priori layers and the averaging kernel, and for this product. Specify a list of names for these variables:
! data variables:
cso.s5p.so2.dvars : hp yr vr A
Example settings:
! half-level pressures:
!~ dimensions, copied from data file:
cso.s5p.so2.dvar.hp.dims : layeri
!~ source variable:
cso.s5p.so2.dvar.hp.source : pressure
! retrieval:
!~ dimensions, copied from data file:
cso.s5p.so2.dvar.yr.dims : retr
!~ source variable:
cso.s5p.so2.dvar.yr.source : vcd
! retrieval error covariance:
!~ dimensions, copied from data file:
cso.s5p.so2.dvar.vr.dims : retr retr
!~ source variable:
cso.s5p.so2.dvar.vr.source : vcd_errvar
! kernel:
!~ dimensions, copied from data file:
cso.s5p.so2.dvar.A.dims : retr layer
!~ source variable:
cso.s5p.so2.dvar.A.source : kernel
For the simulated values, also define a list of variable names that should be created:
! state varaiables to be put out from model:
cso.s5p.so2.vars : mod_conc mod_hp mod_tcc mod_cc xs ys Sx
Example settings:
! model concentration profile:
!~ model layer dimension:
cso.s5p.so2.var.mod_conc.dims : model_layer
!~ standard attributes:
cso.s5p.so2.var.mod_conc.attrs : long_name units
cso.s5p.so2.var.mod_conc.attr.long_name : model SO2 concentrations
cso.s5p.so2.var.mod_conc.attr.units : ppb
! model hpentration profile:
!~ model layer interfaces:
cso.s5p.so2.var.mod_hp.dims : model_layeri
!~ standard attributes:
cso.s5p.so2.var.mod_hp.attrs : long_name units
cso.s5p.so2.var.mod_hp.attr.long_name : model pressure at layer interfaces
cso.s5p.so2.var.mod_hp.attr.units : Pa
! total cloud cover:
!~ no extra dimensions:
cso.s5p.so2.var.mod_tcc.dims :
!~ standard attributes:
cso.s5p.so2.var.mod_tcc.attrs : long_name units
cso.s5p.so2.var.mod_tcc.attr.long_name : total cloud cover
cso.s5p.so2.var.mod_tcc.attr.units : 1
! cloud cover profiles:
!~ model layer dimension:
cso.s5p.so2.var.mod_cc.dims : model_layer
!~ standard attributes:
cso.s5p.so2.var.mod_cc.attrs : long_name units
cso.s5p.so2.var.mod_cc.attr.long_name : cloud cover
cso.s5p.so2.var.mod_cc.attr.units : 1
! model concentrations at apriori layers:
!~ apriori layers:
cso.s5p.so2.var.xs.dims : layer
!~ how computed:
cso.s5p.so2.var.xs.formula : LayerAverage( hp, mod_hp, mod_conc )
cso.s5p.so2.var.xs.formula_terms : hp: hp mod_hp: mod_hp mod_conc: mod_conc
!~ standard attributes:
cso.s5p.so2.var.xs.attrs : long_name units
cso.s5p.so2.var.xs.attr.long_name : model simulations at apriori layers
cso.s5p.so2.var.xs.attr.units : mol m-2
! simulated retrievals
!~ retrieval layers:
cso.s5p.so2.var.ys.dims : retr
!~ how computed:
cso.s5p.so2.var.ys.formula : A x
cso.s5p.so2.var.ys.formula_terms : A: A x: hx
!~ standard attributes:
cso.s5p.so2.var.ys.attrs : long_name units
cso.s5p.so2.var.ys.attr.long_name : simulated retrieval
cso.s5p.so2.var.ys.attr.units : mol m-2
! partial columns as sum over apriori layers
!~ retrieval layers:
cso.s5p.so2.var.Sx.dims : retr
!~ how computed:
cso.s5p.so2.var.Sx.formula : PartialColumns( nla, x )
cso.s5p.so2.var.Sx.formula_terms : nla: nla x: hx
!~ standard attributes:
cso.s5p.so2.var.Sx.attrs : long_name units
cso.s5p.so2.var.Sx.attr.long_name : tropospheric column in local model
cso.s5p.so2.var.Sx.attr.units : mol m-2
Sim-Catalogue¶
The CSO_SimCatalogue
class could be used
to create a catalogue of images for the converted files.
Configuration could look like:
! catalogue creation task:
cso.s5p.so2.sim-catalogue.task.class : cso.CSO_SimCatalogue
cso.s5p.so2.sim-catalogue.task.args : '${PWD}/config/Copernicus/cso-s5p-TRACER.rc', \
rcbase='cso.s5p.so2.sim-catalogue'
The configuration describes where to find a listing file with orbits,
which variables should be plot, the colorbar properties, etc.
See CSO_SimCatalogue
class description for how
the settings in general look like.
The class creates figures for a list of variables:
! variables to be plotted:
cso.s5p.so2.catalogue.vars : yr ys
By default the catalogue creator simply creates a map with the value of the a variable on the track. Optionally settings could be used to specifiy a different unit, or the value range for the colorbar:
! variable:
cso.s5p.so2.sim-catalogue.var.yr.source : data:vcd
! convert units:
cso.s5p.so2.sim-catalogue.var.yr.units : umol/m2
! style:
cso.s5p.so2.sim-catalogue.var.yr.vmin : 0.0
cso.s5p.so2.sim-catalogue.var.yr.vmax : 50.0
! variable:
cso.s5p.so2.sim-catalogue.var.ys.source : state:y
! convert units:
cso.s5p.so2.sim-catalogue.var.ys.units : umol/m2
! style:
cso.s5p.so2.sim-catalogue.var.ys.vmin : 0.0
cso.s5p.so2.sim-catalogue.var.ys.vmax : 50.0
Figures are saved to files with the basename of the original orbit file and the plotted variable:
file://Scratch/cso-catalogue/SO2/2018/06/01/S5p_RPRO_SO2_20180601_1200_yr.png
S5p_RPRO_SO2_20180601_1200_ys.png

To search for interesting features in the data,
the Indexer
class could be used to create index pages.
Configuration could look like:
! index creation task:
cso.s5p.so2.catalogue.task.index.class : utopya.Indexer
cso.s5p.so2.catalogue.task.index.args : '${PWD}/config/Copernicus/cso-s5p-so2.rc', \
rcbase='cso.s5p.so2.catalogue-index'
When succesful, the index creator displays an url that could be loaded in a browser:
Browse to:
file://Scratch/cso-catalogue/SO2/index.html
