Abstract
As an ubiquitous product of the oxidation of many volatile organic
compounds (VOCs), formaldehyde (HCHO) plays a key role as a
short-lived and reactive intermediate in the atmospheric
photo-oxidation pathways leading to the formation of tropospheric
ozone and secondary organic aerosols. In this study, HCHO profiles
have been successfully retrieved from ground-based Fourier transform
infrared (FTIR) solar spectra and UV-visible Multi-AXis Differential
Optical Absorption Spectroscopy (MAX-DOAS) scans recorded during the
July 2010–December 2012 time period at the Jungfraujoch station
(Swiss Alps, 46.5° N, 8.0° E, 3580 m a.s.l.).
Analysis of the retrieved products has revealed different vertical
sensitivity between both remote sensing techniques. Furthermore,
HCHO amounts simulated by two state-of-the-art chemical transport
models (CTMs), GEOS-Chem and IMAGES v2, have been compared to FTIR
total columns and MAX-DOAS 3.6–8 km partial columns, accounting
for the respective vertical resolution of each ground-based
instrument. Using the CTM outputs as the intermediate, FTIR and MAX-DOAS
retrievals have shown consistent seasonal modulations of HCHO
throughout the investigated period, characterized by summertime
maximum and wintertime minimum. Such comparisons have also
highlighted that FTIR and MAX-DOAS provide complementary products
for the HCHO retrieval above the Jungfraujoch station. Finally,
tests have revealed that the updated IR parameters from the HITRAN
2012 database have a cumulative effect and significantly decrease
the retrieved HCHO columns with respect to the use of the HITRAN
2008 compilation.
Citation
ID:
252742
Ref Key:
franco2015atmosphericretrievals