[Paper Review] Tropospheric ozone columns and ozone profiles for Kiev in 2007

А. В. Шаврина, Ya. V. Pavlenko+9 more|arXiv (Cornell University)|Mar 5, 2010

Atmospheric Ozone and Climate8 references3 citations

TL;DR

This study presents ground-based FTIR measurements of tropospheric ozone columns and profiles in Kiev, Ukraine, during March–October 2007, using MODTRAN4 radiative transfer modeling with input from satellite (Aqua-AIRS, Aura-MLS) and surface ozone data. The FTIR-derived total ozone columns show good agreement with OMI-DOAS (bias: −8 to −10 DU, standard error ~2%) and OMI-TOMS (standard error 0.68%), validating the method for regional ozone monitoring and enabling daily photochemical and mixing process analysis in the troposphere.

ABSTRACT

We report on ground-based FTIR observations being performed within the framework of the ESA-NIVR-KNMI project 2907 entitled "OMI validation by ground based remote sensing: ozone columns and atmospheric profiles" for the purpose of OMI data validation. FTIR observations were performed during the time frames August-October 2005, June-October 2006 and March-October 2007, mostly under cloud free and clear sky conditions and in some days from early morning to sunset covering the full range of solar zenith angles possible. Ozone column and ozone profile data were obtained for the year 2005 using spectral modeling of the ozone spectral band profile near 9.6 microns with the MODTRAN3 band model based on the HITRAN-96 molecular absorption database. The total ozone column values retrieved from FTIR observations are biased low with respect to OMI-DOAS data by 8-10 DU on average, where they have a relatively small standard error of about 2%. FTIR observations for the year 2006 were simulated by MODTRAN4 modeling. For the retrieval of ozone column estimates and particularly ozone profiles from our FTIR observations, we used the following data sources to as input files to construct the (a priori) information for the model: satellite Aqua-AIRS water vapor and temperature profiles; Aura-MLS stratospheric ozone profiles (version 1.5), TEMIS climatological ozone profiles and the simultaneously performed surface ozone measurements. Ozone total columns obtained from our FTIR observations for year 2006 with MODTRAN4 modeling are matching rather well with OMI-TOMS and OMI-DOAS data where standard errors are 0.68% and 1.11%, respectively. AURA-MLS data which have become available in 2007 allow us to retrieve tropospheric ozone profiles.

Motivation & Objective

• To validate OMI satellite ozone data using ground-based FTIR observations in a mid-latitude urban environment.
• To retrieve tropospheric ozone profiles using FTIR measurements combined with satellite and surface data.
• To analyze daily photochemical variability and nighttime mixing processes in tropospheric ozone over Kiev.
• To assess the accuracy and reliability of MODTRAN4 modeling for ozone column and profile retrieval under varying atmospheric conditions.
• To establish a long-term ground-truth dataset for regional air quality and climate modeling.

Proposed method

• Conducted ground-based FTIR direct-sun observations using a modernized Infralum FT 801 spectrometer (2–12 μm, ~1 cm⁻¹ resolution).
• Applied MODTRAN4 radiative transfer modeling with HITRAN-96 database to retrieve total ozone columns and profiles from measured spectra.
• Incorporated a priori atmospheric profiles from Aqua-AIRS (water vapor, temperature), Aura-MLS (stratospheric ozone, version 1.5), TEMIS climatology, and in-situ surface ozone measurements.
• Used OMI-DOAS and OMI-TOMS total ozone columns as reference for validation of FTIR retrievals.
• Compared retrieved tropospheric profiles with Aura-TES data when available for validation.
• Performed spectral fitting across the 9.6 μm ozone band using differential optical absorption principles.

Experimental results

Research questions

• RQ1 How well do ground-based FTIR-derived total ozone columns agree with OMI-DOAS and OMI-TOMS satellite data over Kiev?
• RQ2 What is the impact of cloud cover and atmospheric conditions on FTIR ozone retrieval accuracy?
• RQ3 How do tropospheric ozone profiles retrieved from FTIR data compare with Aura-MLS and Aura-TES observations?
• RQ4 What daily photochemical and dynamical processes influence tropospheric ozone variability in the Kiev region?
• RQ5 Can MODTRAN4 modeling with a priori data provide reliable tropospheric ozone profiles for urban monitoring?

Key findings

• FTIR-derived total ozone columns showed a mean bias of −8 to −10 DU relative to OMI-DOAS data, with a small standard error of approximately 2%.
• OMI-TOMS and OMI-DOAS data showed standard errors of 0.68% and 1.11%, respectively, when compared to FTIR results, indicating strong agreement.
• Tropospheric ozone profiles retrieved using MODTRAN4 and a priori data revealed daily photochemical variability, including ozone titration by NOx in the morning and increased concentrations in the afternoon.
• Nighttime mixing processes were observed in the tropospheric ozone profiles, indicating vertical redistribution.
• For days without Aura-TES data, the TEMIS monthly climatological profile was used as a substitute, enabling continuous profile retrieval.
• The study confirms the feasibility of using ground-based FTIR with MODTRAN4 and multi-source a priori data for routine tropospheric ozone monitoring.