Surface ozone-meteorology relationships: Spatial variations and the role
of the jet stream
Abstract
We investigate the relationships among summertime ozone (O3),
temperature, and humidity on daily timescales across the Northern
Hemisphere using observations and model simulations. Temperature and
humidity are significantly positively correlated with O3 across
continental regions in the mid-latitudes (~35-60N). Over
the oceans, the relationships are consistently negative. For continental
regions outside the mid-latitudes, the O3-meteorology correlations are
mixed in strength and sign but generally weak. Over some high latitude,
low latitude, and marine regions, temperature and humidity are
significantly anticorrelated with O3. Daily variations in transport
patterns linked to the position and meridional movement of the jet
stream drive the relationships among O3, temperature, and humidity.
Within the latitudinal range of the jet, there is an increase (decrease)
in O3, temperature, and humidity over land with poleward (equatorward)
movement of the jet, while over the oceans poleward movement of the jet
results in decreases of these fields. Beyond the latitudes where the jet
traverses, the meridional movement of the jet stream has variable or
negligible effects on surface-level O3, temperature, and humidity. The
O3-meteorology relationships are largely the product of the jet-induced
changes in the surface-level meridional flow acting on the background
meridional O3 gradient. Our results underscore the importance of
considering the role of the jet stream and surface-level flow for the
O3-meteorology relationships, especially in light of expected changes to
these features under climate change.