Consistency and quality assessment of the Metop-A/IASI and Metop-B/IASI operational trace gas products (O 3 , CO, N 2 O, CH 4 , and CO 2 ) in the subtropical North Atlantic

• Published in: Atmospheric Measurement Techniques
• Main Authors: O. E. García, E. Sepúlveda, M. Schneider, F. Hase, T. August, T. Blumenstock, S. Kühl, R. Munro, Á. J. Gómez-Peláez, T. Hultberg, A. Redondas, S. Barthlott, A. Wiegele, Y. González, E. Sanromá
• Format: Article in Journal/Newspaper
• Language: English
• Published: Copernicus Publications 2016
• Subjects: Environmental engineering; TA170-171; Earthwork. Foundations; TA715-787; North Atlantic
• Online Access: https://doi.org/10.5194/amt-9-2315-2016; https://doaj.org/article/722a9ef9150e4fa0b62a54613ed67dcb

This paper presents the tools and methodology for performing a routine comprehensive monitoring of consistency and quality of IASI (Infrared Atmospheric Sounding Interferometer) trace gas Level 2 (L2) products (O 3 , CO, N 2 O, CH 4 , and CO 2 ) generated at EUMETSAT (European Organisation for the Exploitation of Meteorological Satellites) using ground-based observations at the Izaña Atmospheric Observatory (IZO, Tenerife). As a demonstration the period 2010–2014 was analysed, covering the version 5 of the IASI L2 processor. Firstly, we assess the consistency between the total column (TC) observations from the IASI sensors on board the EUMETSAT Metop-A and Metop-B meteorological satellites (IASI-A and IASI-B respectively) in the subtropical North Atlantic region during the first 2 years of IASI-B operations (2012–2014). By analysing different timescales, we probe the daily and annual consistency of the variability observed by IASI-A and IASI-B and thereby assess the suitability of IASI-B for continuation of the IASI-A time series. The continuous intercomparison of both IASI sensors also offers important diagnostics for identifying inconsistencies between the data records and for documenting their temporal stability. Once the consistency of IASI sensors is documented we estimate the overall accuracy of all the IASI trace gas TC products by comparing to coincident ground-based Fourier transform infrared spectrometer (FTS) measurements performed at IZO from 2010 to 2014. The IASI L2 products reproduce the ground-based FTS observations well at the longest temporal scales, i.e. annual cycles and long-term trends for all the trace gases considered (Pearson correlation coefficient, R , larger than 0.95 and 0.75 for long-term trends and annual cycles respectively) with the exception of CO 2 . For CO 2 acceptable agreement is only achieved for long-term trends ( R ∼ 0.70). The differences observed between IASI and FTS observations can be in part attributed to the different vertical sensitivities of the two remote sensing ...