A global perspective on atmospheric blocking using GPS radio occultation – one decade of observations
Atmospheric blocking represents a weather pattern where a stationary high-pressure system weakens or reverses the climatological westerly flow at mid-latitudes for up to several weeks. It is closely connected to strong anomalies in key atmospheric variables such as geopotential height, temperatu...
| Main Authors: | , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2017-12-01
|
| Series: | Atmospheric Measurement Techniques |
| Online Access: | https://www.atmos-meas-tech.net/10/4727/2017/amt-10-4727-2017.pdf |
| Summary: | Atmospheric blocking represents a weather pattern where a stationary
high-pressure system weakens or reverses the climatological westerly
flow at mid-latitudes for up to several weeks. It is closely
connected to strong anomalies in key atmospheric variables such as
geopotential height, temperature, and humidity. Here we provide, for
the first time, a comprehensive, global perspective on atmospheric
blocking and related impacts by using an observation-based data set
from Global Positioning System (GPS) radio occultation (RO) from
2006 to 2016. The main blocking regions in both hemispheres and
seasonal variations are found to be represented well in RO data. The
effect of blocking on vertically resolved temperature and humidity
anomalies in the troposphere and lower stratosphere is investigated
for blocking regions in the Northern and Southern hemispheres,
respectively. We find a statistically significant correlation of
blocking with positive temperature anomalies, exceeding 3 K
in the troposphere, and a reversal above the tropopause with negative
temperature anomalies below −3 K in the lower
stratosphere. Specific humidity is positively correlated with
temperature throughout the troposphere with larger anomalies
revealed in the Southern Hemisphere. At the eastern and equatorward
side of the investigated blocking regions, a band of tropospheric
cold anomalies reveals advection of cold air by anticyclonic motion
around blocking highs, which is less distinct in the Southern Hemisphere due to stronger zonal flow. We find GPS RO to be a promising
new data set for blocking research that gives insight into the vertical
atmospheric structure, especially in light of the expected increase
in data coverage that future missions will provide. |
|---|---|
| ISSN: | 1867-1381 1867-8548 |