COBRA (impact of COmbined iodine and Bromine Release on the Arctic atmosphere) was a field campaign in Hudson Bay in Canada in 2008 that studied tropospheric ozone depletion, mercury deposition, oxidant and aerosol chemistry. This campaign was part of the international multidisciplinary Ocean - Atmosphere - Sea Ice - Snowpack (OASIS) program, IPY project 38.

COBRA is funded by a grant (NE/D005914/1) from the Natural Environment Research Council (NERC) International Polar Year Programme.

The COBRA-IPY consortium consists of 16 investigators from seven UK institutions (six Universities and one NERC laboratory), and 6 project partners from three overseas institutions. It includes many world-leading and internationally recognised researchers and leaders in the field of polar and/or atmospheric chemistry and physics. COBRA forms an integral and explicit part of the International OASIS (Ocean-Atmosphere-Sea Ice-Snowpack) IPY programme.