Distribution of hydrogen peroxide and formaldehyde over Central Europe during the HOOVER project

Abstract

Abstract. In this study we report measurements of hydrogen peroxide (H 2 O 2 ), methyl hydroperoxide* (MHP* as a proxy of MHP based on an unspecific measurement of total organic peroxides) and formaldehyde (HCHO) from the HO x OVer EuRope (HOOVER) project (HO x = OH+HO 2 ). HOOVER included two airborne field campaigns, in October 2006 and July 2007. Measurement flights were conducted from the base of operation Hohn (Germany, 54 • N, 9 • E) towards the Mediterranean and to the subpolar regions over Norway. We find negative concentration gradients with increasing latitude throughout the troposphere for H 2 O 2 and CH 3 OOH * . In contrast, observed HCHO is almost homogeneously distributed over central and northern Europe and is elevated over the Mediterranean. In general, the measured gradients tend to be steepest entering the Mediterranean region, where we also find the highest abundances of the 3 species. Mixing ratios of these tracers generally decrease with altitude. H 2 O 2 and CH 3 OOH * show maxima above the boundary layer at 2-5 km, being more distinct over southern than over northern Europe.We also present a comparison of our data with simulations by two global 3-D-models, MATCH-MPIC and EMAC, and with the box model CAABA. The models realistically represent altitude and latitude gradients for both HCHO and hydroperoxides (ROOH). In contrast, the models have problems reproducing the absolute mixing ratios, in particular of H 2 O 2 . Large uncertainties about retention coefficients and Correspondence to: H. Fischer (horst.fischer@mpic.de) cloud microphysical parameters suggest that cloud scavenging might be a large source of error for the simulation of H 2 O 2 . A sensitivity study with EMAC shows a strong influence of cloud and precipitation scavenging on the budget of H 2 O 2 as simulations improve significantly with this effect switched off.

Improved retrieval of global tropospheric formaldehyde columns from GOME-2/MetOp-A addressing noise reduction and instrumental degradation issues

“…During fall, weaker H 2 CO signals are detectable in the vicinity of some urban areas, like for example around Los Angeles and Phoenix, or between Houston and Dallas in eastern Texas, where local petrochemical industry is important (Millet et al, 2008). Maximum summertime concentrations in Europe present lower levels than in America and are observed over broadleaf forests in Central and Eastern Europe (over Germany, Poland, Hungary, Ukraine and Western Russia), and more surprisingly also over closed seas (Mediterranean, Aegean, Black and Caspian Seas), as already observed with OMI measurements (Curci et al, 2010;Sabolis et al, 2011) and with aircraft field campaigns (Klippel et al, 2011).…”

The influence of deep convection on HCHO and H<sub>2</sub>O<sub>2</sub> in the upper troposphere over Europe

“…For the two species, which are central in the present study, some more details will be given next. The hydrogen peroxide measurements have a time resolution of 30 s (time for a calibration signal to rise from 10 to 90 % of total reading), a detection limit of 24 pptv (deduced from the 1σ reproducibility of in-flight zero air measurements) and a precision of ±8.3 % at 260 pptv (deduced from the standard deviation (1σ ) reproducibility of in-flight calibrations with a liquid standard) resulting in a total uncertainty of ±13.9 % at 260 pptv (Klippel et al, 2011).…”

“…In the present configuration, both the range and height maximum were reduced due to the use of two wing pods that housed additional instruments. The instrumentation consisted of a chemiluminescence detector (CLD 790 SR, ECO Physics, Switzerland) for NO, NO 2 and O 3 measurements (Hosaynali Beygi et al, 2011); a set of up-and downward looking 2π -steradian filter radiometers for j (NO 2 ) measurements (Meteorologie Consult GmbH, Germany); a quantum cascade laser IR-absorption spectrometer for CO, CH 4 and HCHO measurements (Schiller et al, 2008); a dual enzyme fluorescence monitor (model AL2001 CA peroxide monitor, Aero-Laser GmbH, Germany) to measure H 2 O 2 and organic hydroperoxides (Klippel et al, 2011); a laser induced fluorescence (LIF) instrument for simultaneous measurements of OH and HO 2 (Martinez et al, 2010;Regelin et al, 2013); a non-dispersive IR-absorption instrument (model LI-6262, LI-COR Inc., USA) for CO 2 and H 2 O measurements ; a proton transfer reaction mass spectrometer (PTR-MS, Ionicon, Austria) for partially-oxidized VOC measurements and a series of canisters for post-flight analysis of non-methane hydrocarbons (Colomb et al, 2006). Details about the instrument performance with respect to time resolution, precision, detection limit and total uncertainty can be found in Klippel et al (2011), Regelin et al (2013) and Bozem et al (2017).…”

“…Emphasis is given to HCHO, which has a medium solubility described by its Henry's law co- (Klippel et al, 2011;Regelin et al, 2013;Bozem et al, 2017).…”

Numerical Modeling of Climate-Chemistry Connections: Recent Developments and Future Challenges

“…This approach enables a direct, point-by-point comparison of model simulation results with in situ and remote sensing observations, similar to ACTM applications, but with a larger uncertainty due to the additional degrees of freedom (in particular sub-grid-scale) of nudged CCMs, which ACTMs usually do not have [29]. The nudging technique can therefore, due to its moderately forced realistic meteorology, be used to analyze and evaluate the atmospheric chemistry sub-system of a CCM under known (since observed) conditions [8,[30][31][32] and much in the same way to interpret observations and test our knowledge about the underlying relevant processes [29,[33][34][35][36].…”