Study of the dependence of long-term stratospheric ozone trends on local solar time

摘要: Abstract. Reliable ozone trends after 2000 are essential to detect early recovery. However, the long-term ground-based and satellite profile reported in literature show a high variability. There multiple reasons for variability such as measurement timing dataset quality. The Payerne Switzerland microwave radiometer (MWR) significantly positive at 2 % 3 % per decade upper stratosphere (5–1  hPa , 35–48  km ), with variation altitude. This is accordance Northern Hemisphere (NH) by other instruments SPARC LOTUS project. In order determine what part of between different datasets comes from timing, MWR SOCOL v3.0 chemistry–climate model (CCM) were estimated each hour day linear regression model. Trends quantified function local solar time (LST). middle stratosphere, differences LST both simulated post-2000 period. these not significant 95 % confidence level. lower mesosphere (1–0.1  48–65  2010–2018 day- nighttime have been considered. Here again, trend Based on results we conclude that cannot be attributed systematic temporal sampling effect. quality primary importance reliable derivation, multi-instrument comparison analyses can used assess stability data records estimating drift bias instruments. The has homogenized ensure stable contribution profiles take into account effects three major instrument upgrades. At upgrade, correction offset calculated using parallel measurements or simultaneous an independent instrument. pressure levels smaller than 0.59  (above ∼50 homogenization corrections applied dependent LST. Due lack reference comparable resolution, comprehensive sub-daily was possible only larger . MWR, Switzerland, compared GROMOS Bern, (MLS, MIPAS, HALOE, SCHIAMACHY, GOMOS), CCM. mean biases series (day- nighttime). agrees within ±5  % MLS over 30 65  altitude range ±10 HARMonized OZone (HARMOZ, limb occultation ENVISAT) range. there large difference datasets, which likely result mesospheric signal aliasing due vertical resolution Hence, induced 55  considered instrumental artifact further analyzed.