Measurement report: Immediate impact of the Taal volcanic eruption 1 on atmospheric temperature observed from COSMIC-2 RO 2 measurements

Abstract

8 For the first time after 43 years of its previous eruption in 1977, the Taal volcano 9 in the Philippines (14°N, 120°.59E) erupted in the afternoon of 12 January, 2020. 10 Interestingly, the Taal volcanic eruption was associated with a strong anticyclonic 11 circulation at the upper levels over the western Pacific region in the northern 12 hemisphere. As a result, the volcanic plumes were carried through the background 13 upper level strong winds to the anticyclone over the Pacific Ocean within a few days 14 following the eruption. In this study, the detailed vertical structure and the day-today 15 temperature variability in response to the eruption is delineated by using high-16 resolution temperature measurements from the recently launched Constellation 17 Observing System for Meteorology, Ionosphere, and Climate (COSMIC)-2 radio 18 occultation (RO) data. We describe the vertical temperature structure near (within 2 19 degree radius) and away (~ 5 degree radius) from the volcano during its intense eruption 20 day (13 January 2020). A significant temperature inversion at ~15 km altitude is 21 observed in the nearest temperature profiles (within 2 degree radius). Multiple 22 tropopauses are evident in the temperature profiles that are available away from the 23 volcano (~ 5 degree radius). The cloud top altitude of 15.2 km detected from the RO 24 bending angle anomaly method is demonstrated. Furthermore, the diurnal temperature 25 and relative humidity anomalies are estimated over ±5 o latitude and longitude radius 26 from the volcano center and over the region of 10-20N, 160-180E with respect to the 27 mean temperature of one week before the eruption. A persistent warming layer is 28 1 https://doi.org/10.5194/acp-2020-513 Preprint. Discussion started: 1 July 2020 c Author(s) 2020. CC BY 4.0 License. observed at 16-19 km altitude range in both regions for several days after the eruption. 29 A strong increase of ~50% relative humidity at 15 km altitude is also noticed just after 30 the eruption in the Taal volcano region. The present work shows the advantages and 31 usefulness of the newly-launched COSMIC-2 data for near real-time temperature 32 monitoring at shorter time scales with sufficient data. 33