Multi-site tropospheric ozone measurements across the North Tropical Atlantic during the summer of 2010

• Published in: Atmospheric environment (1994) 2013-05, Vol.70, p.131-148
• Main Authors: Jenkins, Gregory S., Robjhon, Miliaritiana L., Demoz, Belay, Stockwell, William R., Ndiaye, Seydi A., Drame, Mamadou S., Gueye, Moussa, Smith, Jonathan W., Luna-Cruz, Yaitza, Clark, Johnathan, Holt, Jalisa, Paulin, Casey, Brickhouse, Ashley, Williams, Aneese, Abdullah, Ajamu, Reyes, Ashford, Mendes, Luis, Valentine, Adriel, Camara, Moctar
• Format: Article
• Language: English
• Subjects: African Easterly Waves; air; Atlantic Ocean; atmospheric chemistry; Barbados; Cabo Verde; Cape Verde; Chemical composition and interactions. Ionic interactions and processes; Cyclones; Dust; Earth, ocean, space; Elevated; Exact sciences and technology; External geophysics; hurricanes; Lightning; Marine; Meteorology; mixing; Mixing ratios; Ozone; Saharan air layer; Senegal; summer; Tropics; troposphere
• ISSN: 1352-2310; 1873-2844
• DOI: 10.1016/j.atmosenv.2012.12.019

Ozone soundings are launched during two Intensive Observing Periods (IOPs) from Dakar, Senegal; Sao Vicente, Cape Verde; and St James, Barbados to investigate ozone variability across the North Tropical Atlantic during June/July and August/September 2010. Two objectives of the campaign are to compare background tropospheric ozone mixing ratios and its variability associated with the Saharan Air Layer (SAL) and African Easterly Waves (AEWs) at sites located in the Eastern and Western Tropical Atlantic Ocean. During IOP1 (June–July), reduced ozone mixing ratios are found in the SAL with elevated ozone levels at the SAL's base and above it. During IOP I, the tropospheric column ozone (TCO) is higher at Cape Verde (27.5 DU) when compared to Barbados (19.8 DU). During IOP II (August–September) ozone-rich air is found above 500 hPa prior to the passage of AEW or developing tropical cyclones. The observed larger mixing ratios of middle/upper tropospheric ozone are most prominent at Dakar prior to the passage of an AEW, which we attribute to lightning NOx. During IOP II the tropospheric column ozone is highest at Dakar (30.5 DU) when compared to Cape Verde (20.2 DU) and Barbados (17.2 DU). ► Higher tropospheric column ozone in the Eastern Atlantic relative to the Western Atlantic. ► Higher TCO values during (IOP I) rather than (IOP II) for Barbados and Cape Verde. ► Higher ozone mixing ratios are found in the 925–850 hPa layer in Cape Verde. ► Pre-trough conditions have higher ozone mixing ratios than post-trough conditions.