edu.ucar.opensky::articles:18905 UCAR/NCAR - Library OpenSky Support PO Box 3000 Boulder CO 80307-3000 opensky@ucar.edu http://opensky.ucar.edu/ homepage pointOfContact 2025-12-26T02:40:53.985804 ISO 19115-2 Geographic Information - Metadata - Part 2: Extensions for Imagery and Gridded Data ISO 19115-2:2009(E) https://n2t.org/ark:/85065/d7765h1x Analysis of the latitudinal variability of tropospheric ozone in the Arctic using the large number of aircraft and ozonesonde observations in early summer 2008 2016-10-28T00:00:00Z publication https://n2t.org/ark:/85065/d7765h1x https://doi.org/10.5194/acp-16-13341-2016 Ancellet, G. author Daskalakis, N. author Raut, J. C. author Tarasick, D. author Hair, J. author Quennehen, B. author Ravetta, F. author Schlager, H. author Weinheimer, Andrew author Thompson, A. M. author Johnson, B. author Thomas, J. L. author Law, K. S. author UCAR/NCAR - Library publisher During the 2008 International Polar Year, the POLARCAT (Polar Study using Aircraft, Remote Sensing, Surface Measurements, and Models of Climate Chemistry, Aerosols, and Transport) campaign, conducted in summer over Greenland and Canada, produced a large number of measurements from three aircraft and seven ozonesonde stations. Here we present an observation-integrated analysis based on three different types of O3 measurements: airborne lidar, airborne UV absorption or chemiluminescence measurement, and intensified electrochemical concentration cell (ECC) ozonesonde profiles. Discussion of the latitudinal and vertical variability of tropospheric ozone north of 55° N during this period is performed with the aid of a regional model (WFR-Chem). The model is able to reproduce the O3 latitudinal and vertical variability but with a negative O3 bias of 6–15 ppbv in the free troposphere above 4 km, especially over Canada. For Canada, large average CO concentrations in the free troposphere above 4 km ( >  130 ppbv) and the weak correlation (<  30 %) of O3 and PV suggest that stratosphere–troposphere exchange (STE) is not the major contributor to average tropospheric ozone at latitudes less than 70° N, due to the fact that local biomass burning (BB) emissions were significant during the 2008 summer period. Conversely, significant STE is found over Greenland according to the better O3 vs. PV correlation ( >  40 %) and the higher values of the 75th PV percentile. It is related to the persistence of cyclonic activity during the summer over Baffin Bay. Using differences between average concentration above Northern and Southern Canada, a weak negative latitudinal summer ozone gradient of −6 to −8 ppbv is found in the mid-troposphere between 4 and 8 km. This is attributed to an efficient O3 photochemical production from BB emissions at latitudes less than 65° N, while the STE contribution is more homogeneous in the latitude range 55–70° N. A positive ozone latitudinal gradient of 12 ppbv is observed in the same altitude range over Greenland not because of an increasing latitudinal influence of STE, but because of different long-range transport from multiple mid-latitude sources (North America, Europe, and even Asia for latitudes higher than 77° N). UCAR/NCAR - Library OpenSky Support PO Box 3000 Boulder CO 80307-3000 opensky@ucar.edu http://opensky.ucar.edu/ homepage pointOfContact PDF Text theme Resource Type 2016-01-01T00:00:00Z publication Copyright Author(s) 2016. This work is distributed under the Creative Commons Attribution 3.0 License. None eng geoscientificInformation