A method for methane emissions monitoring at facility scale was developed based on a high precision multi-open-path laser dispersion spectrometer.

This dataset contains the measured data from the experimental study, and the forward simulated data from the convection-diffusion solver used in the simulation study (note: the BSE reconstructions are not supplied). Both the experimental and simulated concentration data can be used for independent processing.

The experimental data consists of methane path-averaged concentrations spatially distributed over the facility under study, together with local meteorology data. The dataset contains 20 days of continuous measurements at a manure management facility on a research farm in Eastern Finland operated by the Natural Resources Institute Finland. The format is .csv and there are two files: 

1) Concentration and meteorological data at 7 sec time steps: 
Halola23_concentration_3Dwind_040523_230523.csv 

The file contains the following variables:
WindSpeedMetresPerSecond - The local wind velocity magnitude in m/s.
SensorLongitude - The longitude coordinate of the sensor location.
SensorLatitude - The latitude coordinate of the sensor location.
SensorName - Name of project.
DateTime - The time stamp for each measurement.
SensorAltitude - The altitude of the sensor in meters above ground.
ReflectorName - ID identifying the retro-reflector used for each open-path measurement.
ReflectorLatitude - The latitude coordinate of the retro for each open-path measurement.
ReflectorLongitude - The longitude coordinate of the retro for each open-path measurement.
ReflectorAltitude - The altitude of the retro for each open-path measurement.
WindDirectionDegrees - The local wind direction in degrees from true North.
WindUMetresPerSecond - The local wind x-component in m/s.
WindVMetresPerSecond - The local wind y-component in m/s.
WindWMetresPerSecond - The local wind z-component in m/s.
TemperatureKelvin - The local atmospheric temperature in K.
PressureMillibar - The local atmospheric pressure in millibar.
HumidityPercent - The local atmospheric humidity in %.
Gas - The gas that is measured.
ConcentrationPpm - The path averaged methane concentration in ppm.
PathLengthMetres - The path length in meters for each open-path.
Quality - Quality indicator of measurement (1-10).


2) High-frequency (2 Hz) wind measurements for estimating turbulent diffusion coefficient: 
Halola23_Hi_res_wind_040523_230523.csv 

The file contains the following variables:
DateTime - The time stamp for each high-frequency wind measurement.
WindDirectionDegrees - The local wind direction in degrees from true North.
WindSpeedMetresPerSecond - The local wind velocity magnitude in m/s.
WindUMetresPerSecond - The local wind x-component in m/s.
WindVMetresPerSecond - The local wind y-component in m/s.
WindWMetresPerSecond - The local wind z-component in m/s.


Finally, the forward simulated concentration fields for each simulation case in the main paper and in the Supplementary Material, corresponding to simulation cases 1-3 and S1-S2. The files are in .mat format and there are 5 files:
forward_result_simulation_case_1.mat 
forward_result_simulation_case_2.mat 
forward_result_simulation_case_3.mat 
forward_result_simulation_case_S1.mat 
forward_result_simulation_case_S2.mat 

Note that simulation case 2 and S2 used a larger FEM grid than the rest of the cases, so the size depends on the simulation case. The files each contain the following variables (n3D = number of nodes, nT = number of timesteps):
a_true - Simulated source distribution in FEM grid (n3D x nT).
c - Simulated concentration distribution in FEM grid (n3D x nT).
r - List of FEM grid nodes [x,y,z] (n3D x 3).
H - FEM grid node connectivity matrix.
nT = Number of time steps.
t_step = Time step size.
vv - Simulated x- and y-components of the velocity field (n3D x 2 x nT).
vz - Simulated z-component of the velocity field (n3D x nT).
x_lim_src - Source domain x-limits.
y_lim_src - Source domain y-limits.
z_lim_src - Source domain vertical limit.