On the dynamics of ozone over ocean and land in the Arctic boundary layer during the spring 2000

During polar sunrise in the Arctic, surface ozone destruction has been routinely observed. This phenomenon occurs within the Arctic mixed boundary layer (100-500 m deep) which is mostly decoupled from the ozone-rich air aloft by strong thermal inversions. The surface ozone depletion is highly episodic and manifested by a sudden decrease of the ozone mixing ratios from ~40 parts per billion by volume (ppbv) to about 0.5 ppbv. Episodes of such unusually low ozone mixing ratios may last for several days. An intensive field campaign "ALERT2000" was organized in winter/spring 2000 near Alert, Nunavut, Canada (82oN, 62oW). During spring 2000 instruments were deployed at an ice camp on the frozen Arctic Ocean surface to investigate spatial and temporal distribution of ozone and deposition to the snowpack. A second instrumented site was set up over land approximately 10 km from the ice camp. A particularly intensive ozone depletion episode occurred during April to May 2000. In this presentation, we will examine the temporal and spatial distribution of ozone over land and frozen ocean before and during ozone depletion episodes. We will report the first results ever recorded about ozone surface deposition employing the eddy covariance approach. Finally, we will define the ocean to atmosphere turbulent exchange of heat and momentum before, during, and after ozone depletion episodes.