Southern Ocean Atmospheric Photochemistry Experiment 2 (SOAPEX-2)

Introduction

SOAPEX-2 is primarily an experiment to study atmospheric cleansing by free radicals in extremely clean and slightly perturbed tropospheric air and focuses on a field campaign carried out at Cape Grim, Tasmania in January-February 1999. more.

SOAPEX-2 involves four groups of tropospheric scientists from the UK and Australia, namely the Universities of East Anglia, Leeds and Leicester along with CSIRO (Commonwealth Scientific Research Organisation), Melbourne.

The clean air photochemistry experiment is an essential prerequisite for experiments carried out in more polluted atmospheres. The data obtained is allowing rigorous testing of basic mechanisms which describe the behaviour of free radical concentrations at differing light levels, water vapour and nitrogen oxide concentrations, etc. The measurements performed in this project are expected to yield valuable information on chemical changes that are affecting the oxidative capacity of the global troposphere and, therefore, the rate at which the global atmosphere can cleanse itself of pollutants. The measurements are also highly relevant to the situation in more polluted atmospheres, where increased levels of confidence in our understanding of atmospheric chemistry is an essential prerequisite to any legislation designed to reduce regional and global pollution.

Objectives

• To quantitatively test fast photochemical theory in clean air.

• To examine perturbations from the baseline situation in polluted continental air containing more complex mixtures of free radical sources and sinks

• Investigation of the balance between tropospheric O3 production and destruction in differing NOx regimes

• A test of instrumental performance

• Testing of models used to simulate chemical processes in the lower atmosphere which are deficient in their description of boundary layer processes

The SOAPEX Gallery