Long-Term NH3 Assesment with Meteorological Parameters to Obtain Temporal Profiles in Agricultural Regions

The impact of climate change on agricultural emissions becomes important, and strongly affects pollutant levels such as NH₃ in the atmosphere. Atmospheric NH₃ levels and emission rates are very sensitive to meteorology factors such as temperature and precipitation. Being one of the major pollutants emitted from agriculture, NH₃ becoming increasingly important, both because it is a pollutant itself and it contributes to the formation of secondary particulate matter. Long-term assessment of IASI NH₃ retrievals showed localized consistent hotspots in some regions of Türkiye, often associated with agricultural activities. Although, the reported emission levels do not chance, there was significant temporal variation observed in the NH₃ retrievals in those regions.

In this study, twelve years of NH₃ retrievals were spatially processed to obtain annual, seasonal and monthly NH₃ distribution maps with a 1x1 km² gridded domain covering whole Türkiye. The results indicated significant temporal variability which also changes according to different regions. The temporal changes of NH₃ for three localized hotspots with significant agricultural activity among the highest NH₃ levels in Türkiye were selected and evaluated as; Igdir (Cold semi-arid), Izmir (Hot summer Mediterranean) and Samsun (Humid sub-tropical). The selection was performed to identify the different climatic conditions, crop and fertilizer types. Level-2 IASI NH₃ retrievals, yearly agricultural statistics, and meteorological measurements were utilized for understanding the changes in NH₃ levels. Among these hotspots, Igdir has the highest seasonal variation with maximum late spring to summer, and Samsun is with least seasonal variation. Within the years investigated, 2015, 2018-2019 and 2022-2023 showed highest number of extreme NH₃ retrievals. This study aims to provide a new approach to the assessment of agricultural NH₃ variability by the long-term assessment to obtain region-specific temporal profiles which the regional air quality models strongly depend on.

Keywords: ammonia, meteorological factors, temporal variation

Acknowledgements: IASI is a joint mission of EUMETSAT and the Centre National d'Etudes Spatiales (CNES, France). The authors acknowledge the AERIS data infrastructure for providing access to the IASI data in this study and ULB-LATMOS for the development of the retrieval algorithms. This study was supported by the Scientific and Technological Research Council of Türkiye under the grant number 123Y364.