Homogenizing and estimating the uncertainty in NOAA's long-term vertical ozone profile records measured with the electrochemical concentration cell ozonesonde
Abstract. NOAA's program of long-term monitoring of the vertical distribution of ozone
with electrochemical concentration cell (ECC) ozonesondes has undergone a
number of changes over the 50-year record. In order to produce a homogenous
data set, these changes must be documented and, where necessary, appropriate
corrections applied. This is the first comprehensive and consistent
reprocessing of NOAA's ozonesonde data records that corrects for these
changes using the rawest form of the data (cell current and pump temperature)
in native resolution as well as a point-by-point uncertainty calculation that
is unique to each sounding. The reprocessing is carried out uniformly at all
eight ozonesonde sites in NOAA's network with differences in sensing solution
and ozonesonde types accounted for in the same way at all sites. The
corrections used to homogenize the NOAA ozonesonde data records greatly
improve the ozonesonde measurements with an average one sigma uncertainty of
 ± 4–6 % in the stratosphere and ± 5–20 % in the troposphere.
A comparison of the integrated column ozone from the ozonesonde profile with
co-located Dobson spectrophotometers total column ozone measurements shows
agreement within ± 5 % for >  70 % of the profiles. Very
good agreement is also found in the stratosphere between ozonesonde profiles
and profiles retrieved from the Solar Backscatter Ultraviolet (SBUV) instruments.