Evaluation of ACE-FTS and OSIRIS Satellite retrievals of ozone and nitric acid in the tropical upper troposphere: Application to ozone production efficiency

Abstract

[1] We evaluate climatologies of upper tropospheric ozone and nitric acid retrieved from two satellite instruments (ACE-FTS and OSIRIS) with long-term in situ measurements from aircraft (MOZAIC, CR-AVE, PRE-AVE, PEM Tropics, and TC4) and ozonesondes. A global chemical transport model (GEOS-Chem) is used to guide the evaluation and to relate sparse in situ measurements with the satellite retrievals. Both satellite retrievals generally reproduce broad ozone features in the upper troposphere such as summer enhancements in the northern subtropics and larger concentrations over the tropical Atlantic versus the tropical Pacific. These comparisons indicate biases in annual, tropical mean ozone concentrations from both ACE-FTS (10-13%) and OSIRIS (5%) relative to aircraft and ozonesonde observations. More uncertain evidence suggests that nitric acid from ACE-FTS has a positive mean bias of 15%. We demonstrate that an upper limit on the ozone production efficiency in the upper troposphere can be determined using ACE-FTS satellite measurements of O 3 and HNO 3 . The resulting value of 196 (+34, −61) mol/mol is in broad agreement with model simulations. Higher OPE values inferred from ACE-FTS over the tropical Pacific (249 (+21, −68) mol/mol) than the tropical Atlantic (146 (+16, −41) mol/mol) reflect increasing ozone production efficiency with decreasing pollution. This analysis indicates a new capability of satellite observations to provide insight into ozone production in the tropical troposphere.

OSIRIS: A Decade of Scattered Light

“…Validation studies of OSIRIS version 5 ozone indicate that the single-profile precision is 3%-6% (Bourassa et al 2012a) and comparisons with benchmark profiling instruments, such as the SAGE II instrument, indicate agreement to within about 5% throughout the stratosphere (Degenstein et al 2009). Comparisons i n t he t ropic a l upp er troposphere show significant agreement with in situ measurements and suggest a bias of approximately 5% when ozone is at 50-75 ppb (Cooper et al 2011). This agreement suggests these data can be used to study the ozone budget of the upper troposphere (Cooper et a l. 2011), a region of the atmosphere difficult to probe.…”

Trend and variability in ozone in the tropical lower stratosphere over 2.5 solar cycles observed by SAGE II and OSIRIS

“…The version 5.07 data (available at ftp://odin-osiris.usask.ca/Level2/daily) have been validated most recently and extensively by Adams et al (2013Adams et al ( , 2014. In the tropical upper troposphere, version 5 biases vs. ozonesondes and aircraft observations reach + 5 % (Cooper et al, 2011). Also using OSIRIS ozone from a different retrieval algorithm, Brohede et al (2007) found a statistically significant +0.045 ppmv year −1 drift at 30 km between 2002 and 2006 at the global scale vs. the submillimetre radiometer (Odin/SMR).…”

“…Figure 5d and f also illustrate that the QBO signature is altitude-dependent and any attempt to fit the QBO signal with time series at a single inappropriate pressure (even with a lag) (e.g. Cunnold et al, 2000;Bodeker et al, 2013) will fail to capture the altitude dependence of the QBO signal. For example, the QBO signal in ozone exhibits sharp temporal changes at the times of extreme amplitude at 24.5 km, whereas at 21.5 km it has much more of a square-wave character (see also Dunkerton and Delisi, 1985).…”

Technical Note: Reanalysis of upper troposphere humidity data from the MOZAIC programme for the period 1994 to 2009

“…In addition, vertical profiles of atmospheric composition (O 3 , CO) collected during ascent after take-off and descent into airports are of increasing importance for satellite validation (e.g. Cooper et al, 2011;Zbinden et al, 2013) and for regional air quality studies including the impact of trans-boundary long-range transport of air pollutants (Cooper et al, 2010;Solazzo et al, 2013).…”