DOI: 10.5443/11405
title: Understanding ozone and mercury in the air over the Arctic Ocean (OASIS)

description: Previous studies took place at the coast, but this project took the next step by making measurements at several locations over the frozen ocean. The composition of the air was measured to learn how it changes over time and space, and the results are now being used to determine what causes ozone and mercury to disappear from the surface air. To undertake these studies over the ocean required the development of novel strategies to bring highly sophisticated instruments, that could operate on batteries, to a hostile environment. The approaches taken were (1) the development of the OOTI sled (Out On The Ice), a movable chemical laboratory that could be deployed by snow mobile to suitable locations on the frozen Arctic Ocean to make detailed short term measurements, and (2) the development of the O-buoy (ozone-buoy) that could be deployed on the ice to make unattended measurements of key chemical species (ozone, carbon dioxide, and bromine monoxide) of the air for about two years, while transmitting the results daily by satellite communication to a ground receiving station. The OOTI sled was deployed during several IPY projects in the spring and summer of 2008-2009. The O-buoy program is operational and growing, measuring atmospheric components on the frozen Hudson Bay, the Beaufort Sea and the Arctic Ocean. Results have confirmed speculations on the large scale of the disappearance of ozone and mercury - depletion episodes in the spring were observed everywhere, were severe, and often lasted several days or weeks - and yielded spectacular information on the processes that are involved. Direct ozone loss to frozen surfaces was usually slow, but mercury was found to deplete and emit around the snow pack. There are indications that these processes may be different over frost flower-covered ice. During some studies it was observed that the disappearances only occurred when the air temperature was below ~ -20°C. This may turn out to be a crucial observation towards understanding how the depletion processes actually operate.
description: Purpose: The central goal of the OASIS-CANADA project is to study atmospheric chemical and physical processes, particularly of ozone and mercury, over the Arctic Ocean. We will do so considering that global warming is occurring, inducing a change in climate that will be especially pronounced in the Arctic, but with unknown feedbacks and implications with respect to inputs of chemical (including toxic) species. It is not our goal to discern actual environmental indicators for change but rather to determine the physical-chemical processes (mechanisms) that take place in the Arctic at the crucial interface between the atmosphere and the ocean below. There can be no doubt that they will have an impact on the nature of climate change and at the same time will be significantly influenced by the change in climate. The OASIS-CANADA proposal forms a unique ensemble of experiments that will benefit from the spotlight that the International Polar Year (IPY) will put on the Arctic. The unprecedented opportunity to study the atmosphere over the ocean requires coordination on international and interdisciplinary scales not otherwise feasible. Observations from space are becoming available and so are sophisticated mathematical models that are used to synthesize the knowledge of the physical nature of the Arctic system. Critically missing in this picture are the in-situ measurements that OASIS-CANADA will provide. The outcomes from this work can be summarized as follows: (1) New, technologically advanced measurement capabilities, required for (unattended) measurements in the remote, hostile, highly sensitive and changing Arctic environment; (2) the initiation of a long term measurement data set from a grid of ozone buoy sites across the Arctic Ocean surface, which will be an essential part of observing, understanding, predicting and preparing for Arctic change in the 21st century; (3) an understanding of interface processes in the Arctic, including the input of toxic chemicals to the polar ecosystem; and (4) a new paradigm for Arctic atmospheric research by the establishment of linkages and understanding with oceanographic and cryospheric scientific disciplines that are currently poorly connected.
description: Summary: Every year when the sun comes up in the Arctic spring, the potent greenhouse gas ozone and the toxic chemical mercury disappear from the air near the ground along the coast of the frozen ocean. It is thought that this is caused by a combination of sunlight, snow and ice, and the low temperature over the frozen ocean. With this project we hope to learn what truly causes the "disappearing act" of these two polluting chemicals, and whether the disappearing mercury ends up in the animals living in the marine world. In collaboration with other partners, once we understand what makes ozone and mercury disappear, we will try to address these questions: Does the mercury that disappears from the air ends up in the Arctic food chain? There is pollution in the Arctic spring coming from down South; What will happen to this pollution if there is less ozone in the air? What will happen to the ozone and mercury if the ice goes away with global warming?