TY - JOUR

T1 - Ozone measurements during the airborne polar experiment: aircraft instrument validation, isentropic trends, and hemispheric fields prior to the 1997 Arctic ozone depletion.

AU - Kyrö, E.

AU - Kivi, R.

AU - Turunen, T.

AU - Aulamo, H.

AU - Rudakov, V. V.

AU - Khattatov, V.

AU - Mackenzie, A. Robert

AU - Chipperfield, M. P.

AU - Lee, A. M.

AU - Stefanutti, L.

AU - Ravegnani, F.

PY - 2000

Y1 - 2000

N2 - The first deployment of the ECOC electro chemical ozone cell (ECOC) instrument onboard the high-altitude research aircraft, the Geophysica M-55, took place from Rovaniemi, northern Finland, between December 23, 1996, and January 14, 1997. The ECOC data were compared against contemporaneous data from a network of balloon-borne ozone sondes. The comparison was carried out in potential vorticity-potential temperature (PV, Θ) coordinates, using meteorological analyses from the European Centre for Medium-Range Forecasts. The comparison showed that ozone mixing ratios measured by ECOC are lower than those measured by ozonesonde by a small but statistically significant bias of (−5.7 ± 2.8)% at the cruising altitudes of the aircraft, 15 to 19 km. After establishing and removing the average bias, ECOC and ozonesonde data were analyzed together to follow the development of ozone distributions in the early winter Arctic stratosphere. The analysis showed no evidence of chemical ozone depletion at the cruising altitudes of the aircraft, that is, between 435 and 490 K. The absence of chemical depletion is in agreement with polar statospheric cloud (PSC) observations, which showed no PSCs at aircraft cruising altitudes, although from January 5 onwards, PSCs were observed above cruising altitudes. Results from a three-dimensional chemical transport model reproduce the basic features of the reconstructed ozone fields. However, the model does not capture the observed ozone increase during the campaign, due to weak modeled ozone vertical gradients, and indicates small ozone depletion of about 3% inside the vortex at 480 K by mid January.

AB - The first deployment of the ECOC electro chemical ozone cell (ECOC) instrument onboard the high-altitude research aircraft, the Geophysica M-55, took place from Rovaniemi, northern Finland, between December 23, 1996, and January 14, 1997. The ECOC data were compared against contemporaneous data from a network of balloon-borne ozone sondes. The comparison was carried out in potential vorticity-potential temperature (PV, Θ) coordinates, using meteorological analyses from the European Centre for Medium-Range Forecasts. The comparison showed that ozone mixing ratios measured by ECOC are lower than those measured by ozonesonde by a small but statistically significant bias of (−5.7 ± 2.8)% at the cruising altitudes of the aircraft, 15 to 19 km. After establishing and removing the average bias, ECOC and ozonesonde data were analyzed together to follow the development of ozone distributions in the early winter Arctic stratosphere. The analysis showed no evidence of chemical ozone depletion at the cruising altitudes of the aircraft, that is, between 435 and 490 K. The absence of chemical depletion is in agreement with polar statospheric cloud (PSC) observations, which showed no PSCs at aircraft cruising altitudes, although from January 5 onwards, PSCs were observed above cruising altitudes. Results from a three-dimensional chemical transport model reproduce the basic features of the reconstructed ozone fields. However, the model does not capture the observed ozone increase during the campaign, due to weak modeled ozone vertical gradients, and indicates small ozone depletion of about 3% inside the vortex at 480 K by mid January.

M3 - Journal article

VL - 105

SP - 14599

EP - 14611

JO - Journal of Geophysical Research: Atmospheres

JF - Journal of Geophysical Research: Atmospheres

SN - 0747-7309

IS - D11

ER -