=== versions ===
python 3.12.0 | rasterio 1.5.2 | xarray 2026.9.0 | numpy 2.5.4 | scipy 1.18.1 | pystac-client 0.9.1

=== Step 1: EMIT methane enhancement from NASA VEDA ===
collection: landfill-emit | EMIT Landfill Plumes | licence CC0-1.0
  EMIT_landfill_cog_2023-06-22: 2023-06-22 | shape [26, 61] | bbox [-121.191, 37.869, -121.158, 37.883] | 81.7% valid
  EMIT_landfill_cog_2023-08-25: 2023-08-25 | shape [956, 592] | bbox [-96.994, 32.521, -96.673, 33.04] | 7.2% valid
read EMIT_landfill_cog_2023-08-25.tif: 592 x 956 px, EPSG:4326, pixel 0.000542 deg | native shape matched: True
15% of horizontally adjacent valid pixels hold identical values (EMIT's orthorectification repeats ~60 m sensor pixels on the output grid)
valid pixels: 40,911 (7.2% of the window) | pixel area 3,055 m2 (~55 m)
enhancement over valid pixels: median 101, 1st pct -1101, 99th pct 1494, max 3096 ppm m

=== Step 2: EMIT plume complexes from the JPL greenhouse gas portal ===
3,372 plume-complex features in the JPL metadata file
McCommas Bluff: CH4_PlumeComplex-1109 at 2023-08-25T17:06:09Z | max 3274 ppm m at (32.6792, -96.7289), 0.6 km from the GHGRP location | JPL emission estimate: NA
Skyline (Ferris): CH4_PlumeComplex-1111 at 2023-08-25T17:06:09Z | max 2298 ppm m at (32.5480, -96.6958), 2.8 km from the GHGRP location | JPL emission estimate: NA
Camelot (Lewisville): CH4_PlumeComplex-1108 at 2023-08-25T17:05:57Z | max 2981 ppm m at (33.0317, -96.9550), 1.6 km from the GHGRP location | JPL emission estimate: NA

=== Step 3: background noise of the enhancement field ===
CH4_PlumeComplex-1108: outline 5,509 px, of which 5,475 carry data
CH4_PlumeComplex-1109: outline 16,307 px, of which 16,250 carry data
CH4_PlumeComplex-1111: outline 18,953 px, of which 18,925 carry data
sigma clipping converged after 3 iterations: median 97 ppm m | robust sigma (1.4826 x MAD) 511 ppm m | 0.62% of pixels above +3 sigma, 0.18% below -3 sigma (Gaussian: 0.13% each)
one-pixel detection limit at 3 sigma: 1,533 ppm m above background

=== Step 4: segment each plume ===
Gaussian smoothing (sigma 1.5 px) cuts the noise from 511 to 238 ppm m

=== Step 5: ERA5 wind, pressure and temperature at the overpass ===
ERA5 subset: {'time': 12, 'latitude': 7, 'longitude': 6} | overpass 2023-08-25 17:05 UTC (12:05 local CDT)
McCommas Bluff: U10 1.05 m/s from 43 deg | U100 1.23 m/s | U10 range over +-2 h 0.98-1.13 m/s | ps 996 hPa | T2m 38.7 C | BLH 1165 m
Skyline (Ferris): U10 1.17 m/s from 51 deg | U100 1.38 m/s | U10 range over +-2 h 1.02-1.19 m/s | ps 996 hPa | T2m 38.6 C | BLH 1083 m
Camelot (Lewisville): U10 0.46 m/s from 67 deg | U100 0.51 m/s | U10 range over +-2 h 0.28-1.27 m/s | ps 993 hPa | T2m 38.8 C | BLH 1625 m

=== Step 6: integrated mass enhancement and emission rate ===
McCommas Bluff: plume origin (smoothed peak) at (32.6863, -96.7272), 1,165 ppm m above background, 796 m from the JPL maximum pixel
McCommas Bluff: 0.6 mg CH4/m2 per ppm m | 2 sigma mask 65 px = 0.20 km2, reaching 0.4 km from the origin
   IME 1.5 sigma: 160 kg, 2.0 sigma: 99 kg, 3.0 sigma: 56 kg
   Q = U10*IME/L 1.5 sigma: 755, 2.0 sigma: 883, 3.0 sigma: 1,097 kg/h
   Varon U_eff 0.66 m/s -> U_eff*IME/sqrt(A) 524 kg/h | range with wind +-2 h and thresholds: 703-1,179 kg/h
   EPA GHGRP 2023: 482,797 t CO2e of CH4 = 19,312 t CH4 = 2,205 kg/h on average
   fetch curve without a mask peaks at r = 1.20 km: IME 877 kg, Q 2,773 kg/h; at r = 5 km the IME is 154 kg
Skyline (Ferris): plume origin (smoothed peak) at (32.5469, -96.6958), 1,134 ppm m above background, 121 m from the JPL maximum pixel
Skyline (Ferris): 0.6 mg CH4/m2 per ppm m | 2 sigma mask 174 px = 0.53 km2, reaching 0.7 km from the origin
   IME 1.5 sigma: 716 kg, 2.0 sigma: 249 kg, 3.0 sigma: 121 kg
   Q = U10*IME/L 1.5 sigma: 1,478, 2.0 sigma: 1,601, 3.0 sigma: 1,431 kg/h
   Varon U_eff 0.78 m/s -> U_eff*IME/sqrt(A) 952 kg/h | range with wind +-2 h and thresholds: 1,244-1,624 kg/h
   EPA GHGRP 2023: 158,052 t CO2e of CH4 = 6,322 t CH4 = 722 kg/h on average
   fetch curve without a mask peaks at r = 0.60 km: IME 313 kg, Q 2,206 kg/h; at r = 5 km the IME is 224 kg
Camelot (Lewisville): plume origin (smoothed peak) at (33.0317, -96.9555), 1,529 ppm m above background, 50 m from the JPL maximum pixel
Camelot (Lewisville): 0.6 mg CH4/m2 per ppm m | 2 sigma mask 61 px = 0.19 km2, reaching 0.4 km from the origin
   IME 1.5 sigma: 157 kg, 2.0 sigma: 135 kg, 3.0 sigma: 112 kg
   Q = U10*IME/L 1.5 sigma: 449, 2.0 sigma: 614, 3.0 sigma: 786 kg/h
   Varon U_eff -0.26 m/s -> U_eff*IME/sqrt(A) undefined (U_eff <= 0 below U10 = 0.58 m/s) | range with wind +-2 h and thresholds: 275-2,173 kg/h
   EPA GHGRP 2023: 105,232 t CO2e of CH4 = 4,209 t CH4 = 481 kg/h on average
   fetch curve without a mask peaks at r = 0.15 km: IME 66 kg, Q 731 kg/h; at r = 5 km the IME is 1,530 kg

                      ime_kg  length_km  U10  q_simple  q_varon    q_lo    q_hi  q_ghgrp
site                                                                                    
McCommas Bluff          98.8        0.4  1.1     883.2    524.4   703.4  1179.1   2204.6
Skyline (Ferris)       248.9        0.7  1.2    1600.6    952.4  1243.9  1624.4    721.7
Camelot (Lewisville)   134.9        0.4  0.5     614.3      NaN   275.0  2172.7    480.5
three landfills together: 3,098 kg/h (range 2,222-4,976) vs GHGRP annual average 3,407 kg/h | ratio 0.91

=== Step 7: Sentinel-2 true colour for context (Planetary Computer) ===
12 Sentinel-2 L2A scenes with <5% cloud within about 10 days

=== Figures ===
Sentinel-2 context scenes used: ['19 Aug 2023']
wrote 01-emit-plumes-landfills.png, 02-noise-histogram.png, 03-plume-mask-mccommas.png, 04-era5-wind.png, 05-ime-fetch-curve.png, 06-emission-comparison.png