Beschreibung:
<jats:p>The partial pressure of CO<jats:sub>2</jats:sub> (<jats:italic>p</jats:italic>CO<jats:sub>2</jats:sub>) was measured during the 1995 South‐West Monsoon in the Arabian Sea. The Arabian Sea was characterized throughout by a moderate supersaturation of 12–30 µatm. The stable atmospheric <jats:italic>p</jats:italic>CO<jats:sub>2</jats:sub> level was around 345 µatm. An extreme supersaturation was found in areas of coastal upwelling off the Omani coast with <jats:italic>p</jats:italic>CO<jats:sub>2</jats:sub> peak values in surface waters of 750 µatm. Such two‐fold saturation (218%) is rarely found elsewhere in open ocean environments. We also encountered cold upwelled water 300 nm off the Omani coast in the region of Ekman pumping, which was also characterized by a strongly elevated seawater <jats:italic>p</jats:italic>CO<jats:sub>2</jats:sub> of up to 525 µatm. Due to the strong monsoonal wind forcing the Arabian Sea as a whole and the areas of upwelling in particular represent a significant source of atmospheric CO<jats:sub>2</jats:sub> with flux densities from around 2 mmol m<jats:sup>−2</jats:sup> d<jats:sup>−1</jats:sup> in the open ocean to 119 mmol m<jats:sup>−2</jats:sup> d<jats:sup>−1</jats:sup> in coastal upwelling. Local air masses passing the area of coastal upwelling showed increasing CO<jats:sub>2</jats:sub> concentrations, which are consistent with such strong emissions.</jats:p>