First comparison of formaldehyde integral contents in ABL retrieved during clear-sky and overcast conditions by ZDOAS technique

Formaldehyde (HCHO) is involved in a lot of chemical reactions in the atmosphere. Taking into account that HCHO basically undergo by photolysis and reaction with hydroxyl radical within a few hours, short-lived VOCs and direct HCHO emissions can cause local HCHO enhancement over certain areas, and, hence, exceeding background level of HCHO can be examined as a local pollution of the atmosphere by VOCs or existence of a local HCHO source. Several retrieval algorithms applicable for DOAS measurements in cloudless were previously developed. In previous works we proposed a new algorithm applicable for the overcast conditions. The algorithm has the typical F-coefficient error of about 10% for winter season, about 5% for summer season, and varying from 15 to 45% for transition season if the atmospheric boundary layer is below the cloud base. In this paper we briefly present our results of the HCHO vertical column retrieval measured at Zvenigorod Scientific Station (ZSS) for overcast. ZSS (55°41'49''N, 36°46'29''E) is located in Moscow region in 38 km west from Moscow. Because Western winds prevail in this region, ZSS is a background station the most part of time. But in cases of Eastern wind, the air quality at ZSS is affected by Moscow megapolis, and polluted air masses formed above Moscow can reach station in a few hours. Due to the absence of alternative overcast data of HCHO, we compare our overcast data with the HCHO vertical content, which we obtained for clear sky. We investigate similarities and differences in their statistical behavior in different air mass. The average overcast HCHO data have similar to clear-sky HCHO positive temperature trends for all wind direction. We found that the average retrieved overcast HCHO contents are systematically greater than the clear-sky retrieval data. But the difference between data retrieved for the overcast and clear-sky conditions are different for Eastern and Western winds. This difference is about 0.5×1016 mol cm-2 for Western winds and about 1.2×1016 mol cm-2 for Eastern winds. We suppose that observed difference between the overcast and clear-sky formaldehyde data can be caused by dependence of chemical reactions leading to the HCHO destruction and the HCHO formation from Moscow anthropogenic predecessors on the cloudy conditions.

[1]  O. Postylyakov.  Spherical Radiative Transfer Model with Computation of Layer Air Mass Factors and Some of Its Applications , 2004 .

[2]  A. N. Borovski,et al.  Measurements of formaldehyde total content in troposphere using DOAS technique in Moscow Region , 2015, Atmospheric and Ocean Optics.

[3]  V. Ivanov,et al.  On the possibility of estimating the volume of NO2 emissions in cities using zenith spectral observations of diffuse solar radiation near 450 nm , 2012 .

[4]  S. Beirle,et al.  Cloud and aerosol classification for 2.5 years of MAX-DOAS observations in Wuxi (China) and comparison to independent data sets , 2015 .

[5]  N. Elansky,et al.  Observations of the ozone and nitrogen dioxide profiles in the TROICA-4 experiment , 2006 .

[6]  G. Golitsyn,et al.  On cloud bottom boundary determination by digital stereo photography from the Earth’s surface , 2017 .

[7]  Maksim S. Andreev,et al.  Estimation of cloud base height using ground-based stereo photography: method and first results , 2014, Remote Sensing.

[8]  Victor Ivanov,et al.  On determination of formaldehyde content in atmospheric boundary layer for overcast using DOAS technique , 2015, Atmospheric and Ocean Optics.

[9]  I. Mokhov,et al.  Variations of Total Nitrogen Oxide Content in the Atmosphere over the North Caucasus , 2016, Russian Meteorology and Hydrology.

[10]  S. Beirle,et al.  Cloud detection and classification based on MAX-DOAS observations , 2013 .

[11]  D. Deirmendjian.  Electromagnetic scattering on spherical polydispersions , 1969 .

[12]  Nicolas Theys,et al.  Improved retrieval of global tropospheric formaldehyde columns from GOME-2/MetOp-A addressing noise reduction and instrumental degradation issues , 2012 .

[13]  Dominik Brunner,et al.  Eight-component retrievals from ground-based MAX-DOAS observations , 2011 .

[14]  Y. Kanaya,et al.  First measurements of formaldehyde integral content in the atmosphere using MAX-DOAS in the Moscow region , 2014 .

[15]  O. V. Postylyakov,et al.  Measurements of formaldehyde total content using DOAS technique: a new retrieval method for overcast , 2014, Asia-Pacific Environmental Remote Sensing.

[16]  Ulrich Platt,et al.  Differential optical absorption spectroscopy , 2008 .

[17]  Aleksandr S. Elokhov,et al.  Ground-based spectrometric measurements of vertical distribution and column abundance of NO2 at Zvenigorod, Russia , 2005, Other Conferences.

[18]  O. V. Postylyakov,et al.  Linearized vector radiative transfer model MCC++ for a spherical atmosphere , 2004 .

[19]  Y. Kanaya,et al.  First measurements of formaldehyde integral content at Zvenigorod Scientific Station , 2013 .

[20]  W. Wiscombe.  Improved Mie scattering algorithms. , 1980, Applied optics.

[21]  F. Hendrick,et al.  A simple and versatile cloud-screening method for MAX-DOAS retrievals , 2014 .

[22]  A. N. Borovski,et al.  Formaldehyde integral content in troposphere of Moscow region: preliminary results of 6 years of measurements using DOAS technique , 2016, Atmospheric and Ocean Optics.

[23]  S. Beirle,et al.  A new method for the absolute radiance calibration for UV–vis measurements of scattered sunlight , 2015 .

[24]  Min Shao,et al.  MAX-DOAS measurements of NO2, HCHO and CHOCHO at a rural site in Southern China , 2012 .