Ground‐based measurements of stratospheric ClO over Spitzbergen in the Arctic spring of 1997

We have measured stratospheric chlorine monoxide (ClO) at Ny Ålesund (79°N), on the Arctic island of Spitzbergen, during the spring of 1997 as part of a ground‐based millimeter‐wave radiometer intercomparison campaign. The presence of ClO in the stratosphere is a direct result of the catalytic destruction of ozone by chlorine and can provide a good measure of this process. Spitzbergen remained well inside the strong, cold polar spring vortex of …