Sensitivity of air pollution simulations with LOTOS-EUROS to the temporal distribution of anthropogenic emissions

Abstract

Abstract. In this study the sensitivity of the model performance of the chemistry transport model (CTM) LOTOS-EUROS to the description of the temporal variability of emissions was investigated. Currently the temporal release of anthropogenic emissions is described by European average diurnal, weekly and seasonal time profiles per sector. These default time profiles largely neglect the variation of emission strength with activity patterns, region, species, emission process and meteorology. The three sources dealt with in this study are combustion in energy and transformation industries (SNAP1), nonindustrial combustion (SNAP2) and road transport (SNAP7). First of all, the impact of neglecting the temporal emission profiles for these SNAP categories on simulated concentrations was explored. In a second step, we constructed more detailed emission time profiles for the three categories and quantified their impact on the model performance both separately as well as combined. The performance in comparison to observations for Germany was quantified for the pollutants NO 2 , SO 2 and PM 10 and compared to a simulation using the default LOTOS-EUROS emission time profiles. The LOTOS-EUROS simulations were performed for the year 2006 with a temporal resolution of 1 h and a horizontal resolution of approximately 25 × 25km 2 .In general the largest impact on the model performance was found when neglecting the default time profiles for the three categories. The daily average correlation coefficient for instance decreased by 0.04 (NO 2 ), 0.11 (SO 2 ) and 0.01 (PM 10 ) at German urban background stations compared to the default simulation. A systematic increase in the correlation coefficient is found when using the new time profiles. The size of the increase depends on the source category, component and station. Using national profiles for road transport showed important improvements in the explained variability over the weekdays as well as the diurnal cycle for NO 2 . The largest impact of the SNAP1 and 2 profiles were found for SO 2 . When using all new time profiles simultaneously in one simulation, the daily average correlation coefficient increased by 0.05 (NO 2 ), 0.07 (SO 2 ) and 0.03 (PM 10 ) at urban background stations in Germany. This exercise showed that to improve the performance of a CTM, a better representation of the distribution of anthropogenic emission in time is recommendable. This can be done by developing a dynamical emission model that takes into account regional specific factors and meteorology.

Curriculum vitae of the LOTOS–EUROS (v2.0) chemistry transport model

“…In a study focused on Germany, timing of emissions was improved by using traffic counts for the road transport sector, electricity demand for the power plant emissions and air temperature for redistributing residential combustion emissions (concept of heating degree days), leading to better model performance. When using all new time profiles simultaneously the time correlation coefficient of daily average values increased by 0.05 (NO 2 ), 0.07 (SO 2 ) and 0.03 (PM 10 ) at urban background stations in Germany (Mues et al, 2014). Ammonia emissions from agriculture are also strongly depending on meteorology (temperature, temperature sums, rain).…”

“…The improvement of emissions and emissions modelling (e.g. Mues et al, 2014;Hendriks et al, 2016b) is and will be one of the focal points of LOTOS-EUROS development and application. It brings together expertise on emission inventorying and data assimilation.…”

“…Currently, satellite products for ammonia are emerging, which show a great promise for the validation of the LOTOS-EUROS model and its emission information (Van Damme et al, 2014). Besides nitrogen deposition, specific attention has been given to the exposure of terrestrial ecosystems to ozone (phytotoxic ozone dose or PODy, accumulated stomatal ozone flux over a threshold) (Bender et al, 2015) and heavy metals (Nickel et al, 2017). Figure 1 illustrates deposition and PODy applications of LOTOS-EUROS over Germany.…”

“…The LOTOS-EUROS model was connected to the regional climate model RACMO2 (van Meijgaard et al, 2008) and two scenario simulations covering the gradual transition of climate (1989-2100) from two global climate models were performed to assess the feedback of climate change on air pollutant concentrations. These simulations showed a significant climate penalty on ozone levels , whereas none was quantified for particulate matter Mues et al, 2013). Also a semi-online coupling between RACMO2 and LOTOS-EUROS was established (Baklanov et al, 2014) and contributed simulations to Phase II of the Air Figure 1.…”

Comparison of tropospheric NO<sub>2</sub> columns from MAX-DOAS retrievals and regional air quality model simulations

“…Multi-axis differential optical absorption spectroscopy (MAX-DOAS) (e.g., Hönninger et al, 2004;Wittrock et al, 2004) measurements have been used to investigate air pollution in many studies, including the FORMAT campaign in northern Italy (Heckel et al, 2005;Wagner et al, 2011), the Cabauw Intercomparison campaign for Nitrogen Dioxide measuring Instruments (CINDI) in the Netherlands (Piters et al, 2012), campaigns in Canada Mendolia et al, 2013), China (e.g., Irie et al, 2011;Hendrick et al, 2014;Ma et al, 2013;Wang et al, 2014) and during shipborne measurements (Leser et al, 2003;Takashima et al, 2012;Peters et al, 2012).…”