DOI: 10.5281/zenodo.16641834
title: GHGSat plume dataset for article "Global satellite survey reveals uncertainty in landfill methane emissions"

description: This dataset provides the GHGSat observations on which the article entitled "Global satellite survey reveals uncertainty in landfill methane emissions" relies. It contains:

 



GHGSat_detected_plumes.csv: a CSV file reporting on all GHGSat observations (positive detections and non-detections). It contains the following columns:



site_ID: waste disposal site identification number

lat: latitude of the GHGSat automatically detected source

lon:  longitude of the GHGSat automatically detected source

Q_t_per_hour: the estimated methane emission rate using the Integrated Mass Enhancement (IME) method, in tons of methane per hour



Note: lat, lon and Q_t_per_hour are all equal to 0.0 for GHGSat observations where no plume has been detected



Q_error_t_per_hour: uncertainty of the estimated methane emission rate using the Integrated Mass Enhancement (IME) method, in tons of methane per hour

year: year of observation (UTC time)

month: month of observation (UTC time)

day: day of observation (UTC time)

hour: hour of observation (UTC time)

minute: minute of observation (UTC time)

second: second of observation (UTC time)

date: timestamp string YYYY-MM-DD hh:mm:ss (UTC time)

obs_ID: GHGSat observation identifier

sat_ID: Number of the GHGSat satellite that made the observation

wind_speed_m_per_s: 10 meter wind speed sampled from GEOS-FP used to quantify the plume emission rate, in meters per second

IME_kg: excess mass of methane observed in the plume, in kg

intermediate_results_L_m: effective plume length, in meters

intermediate_results_effective_wind_speed_m_per_s: effective wind speed computed from wind_speed_m_per_s, in meters per second

conversion_ch4_ppb_to_molm2: methane enhancement conversion factor from ppb to mol/m2

manually_pinned_sources: lat;lon coordinates of the manually verified plume source(s) are provided as a character string, in between parenthesis. If several sources are identified in one plume mask, source coordinates are separated by a double slash (//). For example, if a plume mask shows two manually verified sources, we have manually_pinned_sources="(lat1;lon1//lat2;lon2)".

plume_tif_file_name: file name of the plume in Plume_rasters.zip



The file name structure goes as follows: C[satellite number]_[acquisition date]_[processing date]_[obs_ID]_[emission ID]_CH4PL.tif






 



Plume_rasters.zip: a ZIP file that contains the 1085 detected GHGSat methane plumes in tif format



Note: this file has to be unzipped in order to be able to run the reproduce_GHGSat_rates_in_csv.py python script




 



reproduce_GHGSat_rates_in_csv.py: a small piece of code to read the plume tif files and reproduce the emission rates reported in GHGSat_detected_plumes.csv. It compares the emission rates included in CSV to emission rates recomputed from (1) the IME intermediate results containted in the CSV file; and (2) the raw GHGSat plume tif files contained in Plume_rasters.zip, also using wind speed and conversion factors from the CSV file. The script prints both relative differences in the standard output for the 1085 positive plume detections included in this work. These relative differences are either equal to zero or very small due to numerical floating point errors (<1.0e-13). No emission rate is calculated for non-detections that are reported in the CSV file.


 



requirements.txt: the python libraries and their versions to run ./reproduce_GHGSat_rates_in_csv.py



Note: the python libraries required to run reproduce_GHGSat_rates_in_csv.py can be easily installed with anaconda using the following command line



> conda create --name $ENV_NAME --file requirements.txt