Stratospheric smoke from Australian bushfires

January 24th, 2020 |

GOES-16 Near-Infrared

GOES-16 Near-Infrared “Cirrus” (1.37 µm) images, 19-24 January 2019 [click to play animation | MP4]

GOES-16 (GOES-East) Near-Infrared “Cirrus” (1.37 µm) images during the 19-24 January 2019 period (above) showed a semi-circular pall of smoke that originated from Australian bushfires  — outbreaks of pyrocumulonimbus clouds that occurred in late December 2019 and early January 2020 injected large amounts of smoke into the lower stratosphere, and this smoke drifted eastward across the South Pacific Ocean. The 1.37 µm spectral band does a good job at detecting light scattered by airborne particles such as ice crystals, smoke, volcanic ash, dust, etc.; the areal extent of the smoke was most apparent approaching sunset on each day, due to enhanced forward scattering.

CALIPSO satellite CALIOP lidar data indicated that this smoke often resided at altitudes in the 18-24 km range — one example from 21 January can be seen here. 12-hourly GOES-16 Cirrus images with plots of GFS model 70 hPa wind barbs during the 20-24 January 2019 period (below) showed that winds at the 70 hPa pressure level were generally light.

GOES-16 Near-Infrared "Cirrus" (1.37 µm) images, with plots of GFS model 70 hPa wind barbs (knots), 20-24 January 2019 [click to enlarge]

GOES-16 Near-Infrared “Cirrus” (1.37 µm) images, with plots of GFS model 70 hPa wind barbs (knots), 20-24 January 2019 [click to enlarge]

As the stratospheric smoke feature was beginning to move over the Punta Arena, Chile area (station identifier SCCI), rawinsonde data from that site indicated that the wind speed at 70 hPa (18.5 km) was 18 knots (below).

Plot of rawinsonde data from Punta Arenas, Chile at 12 UTC on 24 January [click to enlarge]

Plot of rawinsonde data from Punta Arenas, Chile at 12 UTC on 24 January [click to enlarge]