First retrieval of tropospheric aerosol profiles using MAX-DOAS and comparison with lidar and sky radiometer measurements

Abstract

Abstract.Ground-based Multi-Axis Differential Optical Absorption Spectroscopy (MAX-DOAS) measurements were performed at Tsukuba, Japan (36.1 • N, 140.1 • E), in November-December 2006. By analyzing the measured spectra of scattered sunlight with DOAS and optimal estimation methods, we first retrieve the aerosol optical depth (τ ) and the vertical profile of the aerosol extinction coefficient (k) at 476 nm in the lower troposphere. These retrieved quantities are characterized through comparisons with coincident lidar and sky radiometer measurements. The retrieved k values for layers of 0-1 and 1-2 km agree with lidar data to within 30% and 60%, respectively, for most cases, including partly cloudy conditions. Results similar to k at 0-1 km are obtained for the retrieved τ values, demonstrating that MAX-DOAS provides a new, unique aerosol dataset in the lower troposphere.

Quantitative bias estimates for tropospheric NO<sub>2</sub> columns retrieved from SCIAMACHY, OMI, and GOME-2 using a common standard for East Asia

“…The quality of our DOAS analysis is supported by formal semi-blind intercomparison results indicating good agreement with other MAX-DOAS observations to within ∼ 10 % of other instruments for both NO 2 and O 4 differential slant column densities ( SCD) and for both the UV and visible regions (Roscoe et al, 2010). The O 4 SCD values derived from the DOAS analysis are converted using our aerosol retrieval algorithm (e.g., Irie et al, 2008) to aerosol optical depth and the vertical profile of the aerosol extinction coefficient. At the same time, the socalled box AMF is uniquely determined, as it is a function of the aerosol profile.…”

“…This set of observations extends the data set used by Irie et al (2009) Table 1). The instrumentation and retrieval algorithm used for all the sites have been described in detail elsewhere (e.g., Irie et al, 2008Irie et al, , 2009Irie et al, , 2011Takashima et al, , 2012. The retrieval utilizes absorption features by NO 2 and the oxygen dimer (O 4 ) at 460-490 nm.…”

NO<sub>2</sub> observations over the western Pacific and Indian Ocean by MAX-DOAS on <i>Kaiyo</i>, a Japanese research vessel

“…Details of the retrieval algorithm have been described elsewhere (e.g. Irie et al, 2008Irie et al, , 2011Takashima et al, 2011).…”

“…The random error was estimated from the residual in the fitting of the NO 2 DSCD, and the systematic error was estimated assuming an additional 30% change in aerosol optical depth (AOD), for which A box varies accordingly. The additional 30 % change in AOD corresponds to its total uncertainty, as estimated empirically from comparisons with independent observations by lidar and sky radiometer at Okinawa Island, Japan , and at Tsukuba, Japan (Irie et al, 2008).…”

The Heidelberg Airborne Imaging DOAS Instrument (HAIDI) – a novel imaging DOAS device for 2-D and 3-D imaging of trace gases and aerosols

“…Tech., 7, 3459-3485, 2014 www Baidar et al, 2013;Dix et al, 2013). This is usually done in a two-stage process using inverse modeling of the atmospheric radiative transfer (e.g., Sinreich et al, 2005;Wagner et al, 2004;Frieß et al, 2006;Irie et al, 2008;Clémer et al, 2010;Wagner et al, 2011). First, the aerosol extinction profile is retrieved from the absorption of the oxygen collision complex O 4 , which has a horizontally constant atmospheric concentration (apart from pressure variations) and therefore serves as a proxy of the light path which is affected by aerosols.…”