We found a match
Your institution may have access to this item. Find your institution then sign in to continue.
- Title
An improved air mass factor calculation for NO<sub>2</sub> measurements from GOME-2.
- Authors
Song Liu; Valks, Pieter; Pinardi, Gaia; Jian Xu; Argyrouli, Athina; Lutz, Ronny; Tilstra, L. Gijsbert; Huijnen, Vincent; Hendrick, François; Van Roozendael, Michel
- Abstract
An improved tropospheric nitrogen dioxide (NO2) retrieval algorithm from the Global Ozone Monitoring Experiment-2 (GOME-2) instrument based on air mass factor (AMF) calculations performed with more realistic model parameters is presented. The viewing angle-dependency of surface albedo is taken into account by improving the GOME-2 Lambertian-equivalent reflectivity (LER) climatology with a directionally dependent LER (DLER) dataset over land and an ocean surface albedo parametrization over water. A priori NO2 profiles with higher spatial and temporal resolutions are obtained from the IFS(CB05BASCOE) chemistry transport model based on recent emission inventories. A more realistic cloud treatment is provided by a Cloud-As-Layers (CAL) approach, which treats the clouds as uniform layers of water droplets, instead of the current Clouds-as-Reflecting-Boundaries (CRB) model, which assumes the clouds as Lambertian reflectors. Improvements in the AMF calculation affect the tropospheric NO2 columns on average within ±15 % in winter and ±5 % in summer over largely polluted regions. In addition, the impact of aerosols on our tropospheric NO2 retrieval is investigated by comparing the concurrent retrievals based on ground-based aerosol measurements (explicit aerosol correction) and aerosol-induced cloud parameters (implicit aerosol correction). Compared to the implicit aerosol correction through the CRB cloud parameters, the use of CAL reduces the AMF errors by more than 10 %. Finally, to evaluate the improved GOME-2 tropospheric NO2 columns, a validation is performed using ground-based Multi-AXis Differential Optical Absorption Spectroscopy (MAXDOAS) measurements at the BIRA-IASB Xianghe station. The improved tropospheric NO2 dataset shows good agreement with coincident ground-based measurements with a correlation coefficient of 0.94 and a relative difference of −9.9 % on average.
- Subjects
AIR masses; TROPOSPHERIC chemistry; EMISSION inventories; TROPOSPHERIC aerosols; CHEMICAL models; OPTICAL spectroscopy; NITROGEN dioxide
- Publication
Atmospheric Measurement Techniques Discussions, 2019, p1
- ISSN
1867-8610
- Publication type
Article
- DOI
10.5194/amt-2019-265