TROPOMI XCH4 retrievals – Official product (TROPOMI / CH4-official)¶
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¶
aggreg_freq: (optional): 1D
Frequency at which to aggregate files into intermediate monitor file
accepted type: str
crop_domain: (optional)
Domain where to keep data. Data outside are discarded
- accepted structure:
xmin: (mandatory)
West boundary
accepted type: float
xmax: (mandatory)
East boundary
accepted type: float
ymin: (mandatory)
South boundary
accepted type: float
ymax: (mandatory)
North boundary
accepted type: float
nlayers: (optional): 12
Number of layers expected in the averaging kernels
accepted type: float
obs_duration: (optional): 0.016666666666666666
Duration of each observation
accepted type: float
stationID: (optional): TROPOMI
Name to put in the ‘station’ column of the output parsed datastore
accepted type: str
networkID: (optional): OFFICIAL
Name to put in the ‘network’ column of the output parsed datastore
accepted type: str
parameter: (optional): CH4
Name of the species to put in the ‘parameter’ column of the output parsed datastore
accepted type: str
std_max: (optional): 0.05
Threshold for standard deviation of ratio weak and strong CH4 column
accepted type: float
cloud_fraction_max: (optional): 0.001
Maximum threshold for cloud fraction
accepted type: float
aot_max: (optional): 0.3
Aerosol optical thickness (NIR)
accepted type: float
chi2_max: (optional): 100
Threshold for chi-square value
accepted type: float
sza_max: (optional): 70
Solar zenith angle
accepted type: float
prec_max: (optional): 10
Precision threshold
accepted type: float
sr_max: (optional): 80
Maximum surface roughness
accepted type: float
sa_min: (optional): 0.02
Minimum surface albedo (SWIR) to keep land only
accepted type: float
qa_value: (optional): 0.5
Keep diagnostic group larger than qa_value
accepted type: float
ws_min: (optional): 0.85
Minimum ratio weak and strong CH4 column
accepted type: float
ws_max: (optional): 1.15
Maximum ratio weak and strong CH4 column
accepted type: float
Yaml template¶
Please find below a template for a Yaml configuration:
1obsparser:
2 plugin:
3 name: TROPOMI
4 version: CH4-official
5 type: obsparser
6
7 # Optional arguments
8 aggreg_freq: XXXXX # str
9 crop_domain:
10 xmin: XXXXX # float
11 xmax: XXXXX # float
12 ymin: XXXXX # float
13 ymax: XXXXX # float
14 nlayers: XXXXX # float
15 obs_duration: XXXXX # float
16 stationID: XXXXX # str
17 networkID: XXXXX # str
18 parameter: XXXXX # str
19 std_max: XXXXX # float
20 cloud_fraction_max: XXXXX # float
21 aot_max: XXXXX # float
22 chi2_max: XXXXX # float
23 sza_max: XXXXX # float
24 prec_max: XXXXX # float
25 sr_max: XXXXX # float
26 sa_min: XXXXX # float
27 qa_value: XXXXX # float
28 ws_min: XXXXX # float
29 ws_max: XXXXX # float
