B913

B913 Scaled by peak value in Gaussian Scaled by area under Gaussian 2 1 3 4 5 6 7 8 9

𝑓=𝑎1exp − 𝑥−𝑏 2 2σ𝑦2 8 9 9 6 6 F Forties 8 Multiple sources? 9 Land. East Knapton?

of concentrations above background for 9 plumes identified so far First-guess histogram (not normalized, etc) of concentrations above background for 9 plumes identified so far number conc / ppb land points, plume 9 number conc / ppb

Hysplit Back trajectory for peak 6

HYSPLIT run with single source at each rig i.e. 7 runs Look at T+20H HYSPLIT concentration along

B913 Best Hysplit results 21/10-FA (scaled) averaged over 1330-1400Z T+20 d Obs (baseline removed) Gaussian fit to obs 𝑓=𝑎0exp − 𝑥−1.159 2 0.0086932 Hysplit FA-Forties Gaussian fit to hysplit conc / ppb 𝑓=𝑎1exp − 𝑥−1.163 2 0.0069682 longitude

Difference between Hysplit and WRF back trajectories… B913 land plume HYSPLIT (web) back trajectory WRF back trajectory nested, 4km resolution in inner domain Difference between Hysplit and WRF back trajectories…

B913 land plume

Identifying the source B913 land plume East Knapton power station distance from methane peak = 3 km Identifying the source

σy = 180 m ±10 m (Matlab) σy = 200 m ±12 m (Stephen) B913 land plume WRF 10 m wind speed at receptor ~ 5 m / s