O3 profiles data using 2025-corrected ECC ozonesonde measurements at OHP

The tropospheric O3 profiles data were obtained by ECC ozonesonde at the OHP (Observatoire de Haute Provence) station belonging to NDACC (Network for Detection of Atmospheric Composition Change) network. It's a french activity from the Service d’Observation NDACC-France of CNRS (Centre National de la Recherche Scientifique)/INSU (Institut National des Sciences de l’Univers) coordinated nationally by OVSQ (Observatoire de l’université de Versailles).

The OHP ECC sondes values have been updated for the period 2002-2023 because we identified two remaining problems:

- step change of altitude values when plotted at constant pressure level (25 hPa, 60 hPa) for
the MODEM sonde period. It is due to a bug in the geopotential altitude calculation from the pressure for this time period. The bias can be as large as 200m above 10 hPa but less than 100 m below 100 hPa.

- low ozone monthly mean value at 25 km when making comparisons with the OHP stratospheric lidar or MLS data for the 2002-2007 period

The low ozone ECC values at 25 km is likely related to a step function in the ECC temperature
in 2002-2007 with TECC being too low when they are compared to the 1997-2001 period. Since the electronics, met sonde and ECC sonde were similar from 1997 to 2007 one must assume that the ECC temperature is underestimated in 2002-2007. This underestimation is low in the troposphere (< 5K) but may be as large as 10 K in the stratosphere.

The correction factor, ECC ozone column and Residual ozone have been updated in the header as well to account for the new altitude value (2008-2023) or the new ozone value (2002-2007). We use also the McPeters method for the residual ozone retrieval for all the dataset (1991-2023)

01/01/2002-21/6/2007: Major TECC correction with linear correction TECCnew=TECCold + alt(km)*10K/30km and new Ozone Partial pressure are calculated using the new TECC

28/6/2007-31/12/2023: Correction of bug in altitude calculation (bias can be 200m above 10 hPa but less than 100 m below 100 hPa )

1991-2023: The McPeters method is now used for the residual ozone column calculation above
the burst altitude and new values are then given for the correction factor