Quantifying Tropopause-Overshooting Volume from Satellite and Radar
Observations during DCOTSS 2021 and 2022 Campaigns
Abstract
This study quantifies the air volume injected into the stratosphere by
overshooting convection detected by GOES-16/17 geostationary infrared
imagery and NOAA NEXRAD precipitation echo top during the 2021 and 2022
Dynamics and Chemistry of the Summer Stratosphere (DCOTSS) missions.
This analysis seeks to address a key DCOTSS science question, namely
“How much tropospheric air and water is irreversibly injected into the
stratosphere by convection?” A novel method for defining individual
storms or a cluster of adjacent storms as objects and tracking them
throughout their lifetime facilitates the analysis. Overshooting
convection injected 2,178,154 - 5,360,162 km3 of air into the
stratosphere in 2021 and 6,017,486 – 10,642,008 km3 in 2022 over the
North American study domain with GOES being higher than GridRad during
both years. GOES overshooting detections were more uncertain due to
difficulty differentiating updrafts from adjacent broad areas of cold
outflow. Overshooting volume from the top 10 storm objects each year
contributed 37 to 52% of the total domain wide volume. Total
object-lifetime volume from these top 10 events ranged from
~90,000-790,000 km3 for GOES and
~49,000-560,000 km3 for GridRad. It was found that
overshooting seldomly exceeded 5% of the total anvil area,
demonstrating that very small regions within convection are responsible
for impacting stratosphere composition. Despite differences in
overshooting characteristics by the two sensors, airmasses initiated
from GOES and NEXRAD overshooting and advected forward in time had
similar spatial and vertical distributions, indicating that
geostationary satellite data could be used to study the long-range
transport of overshooting airmasses.