Ground-based microwave ozone radiometer measurements compared with Aura-MLS v2.2 and other instruments at two Network for Detection of Atmospheric Composition Change sites

Abstract

Ozone measurements made by the Microwave Limb Sounder (MLS) on board the Earth Observing System (EOS) Aura Satellite are compared with measurements made by ground-based microwave radiometers (MWR) in the Network for Detection of Atmospheric Composition Change (NDACC) stations at Lauder, New Zealand (450S, 169°E) and Mauna Loa, Hawaii (20°N, 204°E). The latter instruments measure ozone over the pressure range 56 to 0.03 hPa (about 20 to 72 km), allowing validation of ozone to the upper range of the MLS profiles. In addition, because they operate continuously, separate daytime and nighttime comparisons with MLS can be made to account for the large diurnal variations of ozone in the upper stratosphere and mesosphere. MLS-MWR comparisons show agreement generally within 5% between 24 and 0.04 hPa (about 26 to 70 km) and 5 to 13% elsewhere. To more thoroughly investigate ozone in the stratosphere and mesosphere and establish a consensus between different sets of measurements, comparisons, and analyses with other satellite-borne instruments, including the Stratospheric Aerosol and Gas Experiment II (SAGE-11), Halogen Occultation Experiment (HALOE), Global Ozone Monitoring by Occultation of Stars (GOMOS), and Michelson Interferometer for Passive Atmospheric Sounding (MIPAS), are also made, using the ground-based microwave measurements as a reference. The resulting MLS-consensus difference profiles remove some of the features present in the MLS-MWR comparisons and indicate that the overall agreement between MLS and the correlative data, between 56 and 0.04 hPa, is mostly within 5% at both sites. Copyright 2007 by the American Geophysical Union.