Carbon Dioxide Emissions During the 2018 Kilauea Volcano Eruption Estimated Using OCO‐2 Satellite Retrievals
Matthew S. Johnson, F. M. Schwandner, Christopher Potter, Hai Nguyen, Emily Bell, Robert Nelson, Sajeev Philip, C. O’Dell
Abstract
Abstract This study applies Orbiting Carbon Observatory‐2 (OCO‐2) column‐averaged dry‐air mole fractions of CO 2 (XCO 2 ) to constrain CO 2 fluxes during the 2018 Kilauea volcano eruption. CO 2 enhancements (ΔXCO 2 ) of 1–2 parts per million were observed far downwind of the eruption coincident with elevated sulfur dioxide (SO 2 ) concentrations. The estimated CO 2 emission rate was 77.1 ± 49.6 kilotons per day (kt day −1 ) on 11 July 2018 with most of the uncertainty from modeled winds and XCO 2 retrievals. This emission rate is higher compared to flux estimates made with ground‐based measurements (30–40 kt day −1 ). However, cross‐sectional flux estimates made using OCO‐2 XCO 2 observations will inherently be larger than ground‐based measurements near the source as these estimates comprise all sources of CO 2 in the vicinity of the eruption (e.g., vegetation and soil burning). This study for the first time uses satellite XCO 2 data ~200 km downwind to estimate CO 2 emissions from a major volcanic eruption.