Vortex streets formed in the stratocumulus-capped wake of mountainous islands are the atmospheric analogues of the classic Kármán vortex street observed in laboratory flows past bluff bodies. The quantitative analysis of these mesoscale unsteady atmospheric flows has been hampered by the lack of satellite wind retrievals of sufficiently high spatial and temporal resolution. Taking advantage of the cutting-edge Advanced Baseline Imager, we derived km-scale cloud-motion winds at 5-minute frequency for a vortex street in the lee of Guadalupe Island imaged by Geostationary Operational Environmental Satellite-16. Combined with Moderate Resolution Imaging Spectroradiometer data, the geostationary imagery also provided accurate stereo cloud-top heights. The time series of geostationary winds, supplemented with snapshots of ocean surface winds from the Advanced Scatterometer, allowed us to capture the wake oscillations and measure vortex shedding dynamics. The retrievals revealed a markedly asymmetric vortex decay, with cyclonic eddies having larger peak vorticities than anticyclonic eddies at the same downstream location. Drawing on the vast knowledge accumulated about laboratory bluff body flows, we argue that the asymmetric island wake arises due to the combined effects of Earth’s rotation and Guadalupe’s non-axisymmetric shape resembling an inclined flat plate at low angle of attack. The asymmetric vortex decay implies a three-dimensional wake structure, where centrifugal or elliptical instabilities selectively destabilize anticyclonic eddies by introducing edge-mode or core-mode vertical perturbations to the clockwise-rotating vortex tubes.

Stereo methods using GOES-17 and Himawari-8 applied to the Hunga Tonga-Hunga Ha’apai volcanic plume on 15 January 2022 show overshooting tops reaching 50-55 km altitude, a record in the satellite era. Plume height is important to understand dispersal and transport in the stratosphere and climate impacts. Stereo methods, using geostationary satellite pairs, offer the ability to accurately capture the evolution of plume top morphology quasi-continuously over long periods. Manual photogrammetry estimates plume height during the most dynamic early phase of the eruption and a fully automated algorithm retrieves both plume height and advection every 10 minutes during a more frequently sampled and stable phase beginning three hours after the eruption. Stereo heights are confirmed with Global Navigation Satellite System Radio Occultation (GNSS-RO) bending angles, showing that most of the plume was lofted 30–40 km into the atmosphere. Cold bubbles are observed in the stratosphere with brightness temperature of ~173K.