1. Αποθετήριο Παραδοτέων Υποτρόφων Δράσεων ΕΣΠΑ Τριτοβάθμιας Εκπαίδευσης 2017-2023
2. Όλο το Αποθετήριο
3. Ερευνητικές ομάδες

Τύπος:	Άρθρο σε επιστημονικό περιοδικό
Τίτλος:	Five years of spatially resolved ground-based MAX-DOAS measurements of nitrogen dioxide in the urban area of Athens: synergies with in situ measurements and model simulations
Συγγραφέας:	[EL] Γρατσέα, Μυρτώ[EN] Gratsea, Myrto [EL] Αθανασοπούλου, Ελένη[EN] Athanasopoulou, Eleni [EL] Κακούρη, Αναστασία[EN] Kakouri, Anastasia [DE] Richter, Andreas [DE] Seyler, André [EL] Γερασόπουλος, Ευάγγελος[EN] Gerasopoulos, Evangelos
Ημερομηνία:	07/12/2021
Περίληψη:	Long-term nitrogen dioxide (NO2) slant column density measurements using the MAX-DOAS (multi-axis differential optical absorption spectroscopy) technique were analyzed in order to demonstrate the temporal and horizontal variability of NO2 in Athens for the period October 2012–July 2017. Synergies with in situ measurements and model simulations were exploited in order to verify the ability of the MAX-DOAS technique to assess the spatiotemporal characteristics of NO2 pollution. Tropospheric NO2 columns derived from ground-based MAX-DOAS observations in two horizontal and five vertical viewing directions were compared with in situ measurements representative of urban, urban background and suburban conditions; a satisfactory correlation was found for the urban (r = 0.55) and remote areas (r = 0.40). Mean tropospheric slant columns retrieved from measurements at the lowest elevation over the urban area ranged from 0.1 to 32 * 1016 molec cm2. The interannual variability showed a rate of increase of 0.3 * 1016 molec cm2 per year since 2012 in the urban area, leading to a total increase of 20%. The retrieved annual cycles captured the seasonal variability with lower NO2 levels in summer, highly correlated (r = 0.85) with the urban background and suburban in situ observations. The NO2 diurnal variation for different seasons exhibited varied patterns, indicating the different role of photochemistry and anthropogenic activities in the different seasons. Compared to in situ observations, the MAX-DOAS NO2 morning peak occurred with a one-hour delay and decayed less steeply in winter. Measurements at different elevation angles are shown as a primary indicator of the vertical distribution of NO2 at the urban environment; the vertical convection of the polluted air masses and the enhanced NO2 near-surface concentrations are demonstrated by this analysis. The inhomogeneity of the NO2 spatial distribution was shown using a relevant inhomogeneity index; greater variability was found during the summer period. Comparisons with city-scale model simulations demonstrated that the horizontal light path length of MAX-DOAS covered a distance of 15 km. An estimation of urban sources’ contribution was also made by applying two simple methodologies on the MAX-DOAS measurements. The results were compared to NO2 predictions from the high resolution air quality model to infer the importance of vehicle emissions for the urban NO2 levels; 20–35% of the urban NO2 was found to be associated with road transport.
Γλώσσα:	Αγγλικά
Σελίδες:	19
DOI:	10.3390/atmos12121634
EISSN:	2073-4433
Θεματική κατηγορία:	[EL] Μετεωρολογία και Επιστήμες της ατμόσφαιρας[EN] Meteorology and Atmospheric Sciences
Λέξεις-κλειδιά:	ground-based MAX-DOAS; tropospheric NO2; urban pollution
Κάτοχος πνευματικών δικαιωμάτων:	© 2021 by the authors. Licensee MDPI, Basel, Switzerland.
Όροι και προϋποθέσεις δικαιωμάτων:	This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/).
Ηλεκτρονική διεύθυνση του τεκμηρίου στον εκδότη:	https://www.mdpi.com/2073-4433/12/12/1634
Ηλεκτρονική διεύθυνση περιοδικού:	https://www.mdpi.com/journal/atmosphere
Τίτλος πηγής δημοσίευσης:	Atmosphere
Τεύχος:	12
Τόμος:	12
Σελίδες τεκμηρίου (στην πηγή):	Article no 1634
Σημειώσεις:	This research was funded by Greece and the European Union (European Social Fund- ESF) through the Operational Programme “Human Resources Development, Education and Lifelong Learning 2014–2020” in the context of the project “Three-dimensional distribution of NO2 (nitrogen dioxide) in the urban environment of Athens, using the MAX-DOAS passive remote sensing technique” (MIS 5049920).
Εμφανίζεται στις συλλογές:	Ερευνητικές ομάδες