Relative drifts and stability of satellite and ground-based stratospheric ozone profiles at NDACC lidar stations

Abstract

The long-term evolution of stratospheric ozone at different stations in the low and mid-latitudes is investigated. The analysis is performed by comparing the collocated profiles of ozone lidars, at the northern mid-latitudes (Meteorological Observatory Hohenpeißenberg, Haute-Provence Observatory, Tsukuba and Table Mountain Facility), tropics (Mauna Loa Observatory) and southern mid-latitudes (Lauder), with ozonesondes and space-borne sensors (SBUV(/2), SAGE II, HALOE, UARS MLS and Aura MLS), extracted around the stations. Relative differences are calculated to find biases and temporal drifts in the measurements. All measurement techniques show their best agreement with respect to the lidar at 20–40 km, where the differences and drifts are generally within ±5% and ±0.5% yr<sup>−1</sup>, respectively, at most stations. In addition, the stability of the long-term ozone observations (lidar, SBUV(/2), SAGE II and HALOE) is evaluated by the cross-comparison of each data set. In general, all lidars and SBUV(/2) exhibit near-zero drifts and the comparison between SAGE II and HALOE shows larger, but insignificant drifts. The RMS of the drifts of lidar and SBUV(/2) is 0.22 and 0.27% yr<sup>−1</sup>, respectively at 20–40 km. The average drifts of the long-term data sets, derived from various comparisons, are less than ±0.3% yr<sup>−1</sup> in the 20–40 km altitude at all stations. A combined time series of the relative differences between SAGE II, HALOE and Aura MLS with respect to lidar data at six sites is constructed, to obtain long-term data sets lasting up to 27 years. The relative drifts derived from these combined data are very small, within ±0.2% yr<sup>−1</sup>

Drift-corrected trends and periodic variations in MIPAS IMK/IAA ozone measurements

“…One wavelength is 308 nm for all lidars, while the reference wavelength is 353 nm at Hohenpeissenberg and Lauder and 355 nm for the other lidars during the investigated time period. Lidar measurements become less reliable with altitude, which is reflected in deteriorating precision from approximately 1 % up to 30 km through about 2-5 % around 40 km to up to 25 % at 50 km (Nair et al, 2012). Most lidars have vertical resolutions of around 2 km for altitudes below 30 km, which then increases rapidly above.…”

Comparison of ozone profiles from DIAL, MLS, and chemical transport model simulations over Río Gallegos, Argentina, during the spring Antarctic vortex breakup, 2009

“…The O 3 profiles from DIAL are used to evaluate the bias and drift, i.e., long-term stability of satellite measurements (e.g., Nair et al, 2012;Eckert et al, 2014;Hubert et al, 2016). Therefore, it is important to show the quality of the respective ground-based DIAL performance.…”

“…MLS has covered the location of OAPA (51.6 • S) on a daily basis since measurements began in 2005. The long-term stability of the MLS ozone dataset has been shown to be very good (e.g., Nair et al, 2012;Hubert et al, 2016). For comparison between DIAL and MLS, the DIAL profile is convolved using the following equation :…”

“…O 3 measurements from DIAL have a high vertical resolution and measurements have shown long-term stability (Nair et al, 2012;Hubert et al, 2016), owing to the stratospheric ozone lidar sites of NDACC (e.g., Leblanc and McDermid, 2000;Brinksma et al, 2002;Godin-Beekmann et al, 2003;Steinbrecht et al, 2009). To target the stratosphere, O 3 number density is usually retrieved between 15 and 45 km in geometric altitude.…”

“…However, its drift, i.e., the long-term measurement stability, should be quantitatively assessed with independent instruments. Ground-based ozone lidar is a potential candidate for such purposes and can be used to estimate drift (e.g., Nair et al, 2011Nair et al, , 2012Eckert et al, 2014;Hubert et al, 2016). Hubert et al (2016) comprehensively evaluated the bias and drift of 14 limb-viewing satellite sensors using ozonesonde and ozone lidar measurements.…”