Improvement of Total and Tropospheric NO2 Column Retrieval for GOME-2

This contribution focuses on the development and refinement of novel scientific algorithms for the retrieval of total and tropospheric nitrogen dioxide (NO2) columns for the GOME-2 satellite instrument. NO2 plays significant roles in atmospheric chemistry. It strongly related to ozone destruction in the stratosphere, and is regarded as an important air pollutant and ozone precursor in the troposphere. Total NO2 columns from GOME-2 are retrieved with the Differential Optical Absorption Spectroscopy (DOAS) method using the large 425-497 nm wavelength fitting window in order to increase the signal to noise ratio. The tropospheric NO2 column is derived using an improved Stratospheric-Tropospheric separation (STS) algorithm, followed by an air mass factor (AMF) conversion calculated with the LIDORT model. For the calculation of the tropospheric AMF, improved GOME-2 cloud parameters are used and a new surface albedo (LER) climatology based on GOME-2 observations for 2007-2013 is applied. We present the improvements in the NO2 retrieval algorithm, and we show examples of air quality applications with GOME-2 NO2 data.