CO measurements from the ACE-FTS satellite instrument: data analysis and validation using ground-based, airborne and spaceborne observations

摘要

The Atmospheric Chemistry Experiment (ACE) mission was launched in August2003 to sound the atmosphere by solar occultation. Carbon monoxide (CO), agood tracer of pollution plumes and atmospheric dynamics, is one of the keyspecies provided by the primary instrument, the ACE-Fourier TransformSpectrometer (ACE-FTS). This instrument performs measurements in both the CO1-0 and 2-0 ro-vibrational bands, from which vertically resolved COconcentration profiles are retrieved, from the mid-troposphere to thethermosphere. This paper presents an updated description of the ACE-FTSversion 2.2 CO data product, along with a comprehensive validation of theseprofiles using available observations (February 2004 to December 2006). Wehave compared the CO partial columns with ground-based measurements usingFourier transform infrared spectroscopy and millimeter wave radiometry, andthe volume mixing ratio profiles with airborne (both high-altitude balloonflight and airplane) observations. CO satellite observations provided bynadir-looking instruments (MOPITT and TES) as well as limb-viewing remotesensors (MIPAS, SMR and MLS) were also compared with the ACE-FTS COproducts. We show that the ACE-FTS measurements provide CO profiles withsmall retrieval errors (better than 5% from the upper troposphere to 40km, and better than 10% above). These observations agree well with thecorrelative measurements, considering the rather loose coincidence criteriain some cases. Based on the validation exercise we assess the followinguncertainties to the ACE-FTS measurement data: better than 15% in theupper troposphere (8–12 km), than 30% in the lower stratosphere (12–30 km), and than 25% from 30 to 100 km.