Ozone correlation lengths and measurement uncertainties from analysis of historical ozonesonde data in North America and Europe

A spatial and temporal correlation analysis is performed on the WOUDC (World Ozone and Ultraviolet Radiation Data Centre) ozonesonde data from 13 midlatitude stations in North America and Europe. The data records span more than 40 years at some stations, and a total of more than 27,000 ozonesonde profiles are utilized. The spatial correlation coefficients between pairs of stations decrease with increasing station separation distance, following a power exponential correlation function. The horizontal distance for the correlation coefficient to decrease by a factor of e is about 1000–2000 km in the stratosphere with a peak at around 22‐km altitude, and is about 500–1000 km in the troposphere. The autocorrelation coefficient decreases rapidly with time lag, and the timescale of the autocorrelation varies between about 1.5 and 3.5 days in the troposphere but is generally longer in the stratosphere at 2–6 days. The extrapolation of the correlation functions to zero station distance or zero time lag yields estimates of the intrinsic uncertainty of ozonesonde measurements. The uncertainty is found to be less than 7% for 20–30‐km altitudes in the stratosphere, about 15% in the troposphere, and to have larger values near the tropopause and at the surface. The results are broadly consistent with those from the recent JOSIE and BESOS experiments, and other intercomparisons, with the additional measurement uncertainty probably reflecting changes in ozonesonde type, model, manufacture, and preparation procedure during the period of the record.