Polar Vortex Outbreak Air Transport: Observation using Satellite IR
Sounder Derived Products and Comparison with Model
Abstract
The Single Field of View (SFOV) Sounder Atmospheric Products (SiFSAP)
derived from Cross-track Infrared Sounder (CrIS) on SNPP have a spatial
resolution ( ~15 km) better than most global weather and
climate models and current operational sounding products. Most recent
significant improvement in its quality provides us an opportunity to use
SiFSAP sounding data, which will soon be available at NASA DAAC for
weather studies and model evaluation. This presentation used SiFSAP
together with two model data, i.e. NASA’s Modern-Era Retrospective
Analysis for Research and Applications Version-2 (MERRA-2) and the
fifth-generation ECMWF reanalysis (ERA5) data, to study the dynamic
transport associated with Cold Air Outbreak (CAO) on Jan 29, 2019, and
its relationship with polar vortex. In this case study, the changes of
temperature (T), water vapor, ozone (O3), wind fields, geopotential
height (GPH) and potential velocity (PV), as well as O3 from OMPS on
SNPP were analyzed and compared. We found the cold air transport near
the surface can be linked with the folding of tropopause, which brought
O3-riched and dry stratospheric air to lower altitudes in the
atmosphere. The transport path of cold air from polar to lower latitude
can be well mapped from the enhanced O3, low relative humidity (RH),
wind fields and PV contours. The change of surface T has a high
correlation (R>0.8) with O3. Some difference between models
and satellite observations of T and RH from the latitude-pressure and
longitude-pressure cross-section is found. These results demonstrate the
3-D structures of T, RH and O3 distribution as derived from CrIS
measurements provide some insights of the cold air transport, and have a
potential to be used to monitor the transport of polar cold air
following the outbreak of polar vortex.