Problems to be solved
There are still discrepancies between model prediction and observations of the year- round stratospheric ozone decline in mid and high latitudes. In summer, current models still severely overestimate ozone in the polar regions, and this appears as a major deficiency in our ability to model the complete ozone seasonal cycle. The springtime mid-latitude ozone depletion has not been satisfactorily modelled in a quantitative manner. This proposal hence aims at improving our understanding and modelling of ozone loss processes throughout spring and summer, in the northern mid and high latitudes.
Scientific objectives and approach
The main scientific objective is to acquire a quantitative understanding of:
(i) the mid-latitude ozone depletion accompanying the breakdown of the wintertime polar vortex, especially over Europe, and
ii) the Arctic summer ozone deficit and its linkage to midlatitudes.
The project relies on using an integrated approach combining ground-based and balloon-borne measurements, global satellite observations, as well as advanced chemical/dynamical modelling and data assimilation. Measurements of ozone, inert gases, or species actively involved in ozone chemistry, are made at three different stations in the Arctic throughout spring and summer. Observational techniques comprise ground-based lidar and infrared spectroscopic measurements, and lightweight balloon-borne instrumentation. Satellite observations complement these local, ground-based and in-site measurements by allowing characterising the global, evolving three-dimensional ozone distribution. The satellite data are globally integrated into a transport model through data assimilation. State-of-the-art numerical models are used to investigate the interaction of chemistry and mixing in the spring and summer stratosphere. These models are used to diagnose the ozone loss mechanisms and the overall transport of trace species in spring and summer. Correlative studies of the abundance of various trace species, either modelled or measured, allow to disentangle the effect of mixing from chemical sources and sinks.
The information to be provided by the field campaigns and model studies during SAMMOA will improve the quantification of ozone loss in the stratosphere, a key science priority in support of the Montreal protocol. This project will particularly impact on understanding of ozone depletion in spring and summer, when it is most harmful. It is indeed in the summertime, that human exposure to UV radiation is largest in middle latitudes. Modelling improvements shall result in better assessment and prediction of the ozone trend and recovery in support of regulatory protocols.
Funding SchemeCSC - Cost-sharing contracts
14473 Gross Glienicke Potsdam
3730 AE De Bilt
981 28 Kiruna
981 28 Kiruna
OX1 3RH Oxford
LS2 9JT Leeds
CB2 1EW Cambridge