TROPOMI XCH4 retrievals from SRON TROPOMI/CH4-SRON

TROPOMI XCH4 retrievals from SRON TROPOMI/CH4-SRON#

Description#

This plugin reads TROPOMI XCH4 retrievals as provided by SRON. Data can be downloaded here: `https://ftp.sron.nl/open-access-data-2/TROPOMI/tropomi/ch4/19_446/`__.

The data is described in Lorente et al. (2021)

For filtering data, the product User Guide mentions that:

The most relevant filtering criteria are:

  • Cloud fraction < 0.001 (IFOV, OFOV)

  • Ratio weak and strong CH 4 column 0.85 - 1.15

  • Standard deviation of ratio weak and strong CH 4 column < 0.05

  • Aerosol optical thickness (NIR) < 0.3

  • chi2 < 100

  • Solar zenith angle < 70

  • Precision < 10 ppb

  • Surface roughness < 80 m

  • Surface albedo (SWIR) > 0.02 (only land)

  • with the parameter ’qa_value’ in the diagnostics group equal to 1

YAML arguments#

The following arguments are used to configure the plugin. pyCIF will return an exception at the initialization if mandatory arguments are not specified, or if any argument does not fit accepted values or type:

Optional arguments#

orbit_range : optional

Range of orbit IDs to cover

Argument structure:
orb_min : int, optional, default -10

Minimum orbit ID

orb_max : int, optional, default 10000000

Minimum orbit ID

aggreg_freq : str, optional, default “1D”

Frequency at which to aggregate files into intermediate monitor file

crop_domain : optional

Domain where to keep data. Data outside are discarded

Argument structure:
xmin : float, mandatory

West boundary

xmax : float, mandatory

East boundary

ymin : float, mandatory

South boundary

ymax : float, mandatory

North boundary

nlayers : float, optional, default 12

Number of layers expected in the averaging kernels

obs_duration : float, optional, default 0.016666666666666666

Duration of each observation

stationID : str, optional, default “TROPOMI”

Name to put in the ‘station’ column of the output parsed datastore

networkID : str, optional, default “KNMI-SRON”

Name to put in the ‘network’ column of the output parsed datastore

parameter : str, optional, default “CH4”

Name of the species to put in the ‘parameter’ column of the output parsed datastore

std_max : float, optional, default 0.05

Threshold for standard deviation of ratio weak and strong CH4 column

cloud_fraction_max : float, optional, default 0.001

Maximum threshold for cloud fraction

aot_max : float, optional, default 0.3

Aerosol optical thickness (NIR)

chi2_max : float, optional, default 100

Threshold for chi-square value

sza_max : float, optional, default 70

Solar zenith angle

prec_max : float, optional, default 10

Precision threshold

sr_max : float, optional, default 80

Maximum surface roughness

sa_min : float, optional, default 0.02

Minimum surface albedo (SWIR) to keep land only

qa_value : float, optional, default 1

Keep diagnostic group equal to qa_value

ws_min : float, optional, default 0.85

Minimum ratio weak and strong CH4 column

ws_max : float, optional, default 1.15

Maximum ratio weak and strong CH4 column

YAML template#

Please find below a template for a YAML configuration:

 1obsparser:
 2  plugin:
 3    name: TROPOMI
 4    version: CH4-SRON
 5    type: obsparser
 6
 7    # Optional arguments
 8    orbit_range:
 9      orb_min: XXXXX  # int
10      orb_max: XXXXX  # int
11    aggreg_freq: XXXXX  # str
12    crop_domain:
13      xmin: XXXXX  # float
14      xmax: XXXXX  # float
15      ymin: XXXXX  # float
16      ymax: XXXXX  # float
17    nlayers: XXXXX  # float
18    obs_duration: XXXXX  # float
19    stationID: XXXXX  # str
20    networkID: XXXXX  # str
21    parameter: XXXXX  # str
22    std_max: XXXXX  # float
23    cloud_fraction_max: XXXXX  # float
24    aot_max: XXXXX  # float
25    chi2_max: XXXXX  # float
26    sza_max: XXXXX  # float
27    prec_max: XXXXX  # float
28    sr_max: XXXXX  # float
29    sa_min: XXXXX  # float
30    qa_value: XXXXX  # float
31    ws_min: XXXXX  # float
32    ws_max: XXXXX  # float
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