TEMPORAL VARIATIONS OF PCO(2) IN SURFACE SEAWATER OF THE ARABIAN SEA IN 1995

As part of the JGOFS program in the Arabian Sea we continually measure d the partial pressure of CO, gas in surface seawater (pCO(2)(sea)) an d in the atmosphere above the sea surface (pCO(2)(air)) along six simi lar cruise tracks in January, February, March, July, November, and Dec ember of 1995. The observed variations of pCO(2)(sea) reached over 260 mu atm close to the Omani coast in January-February and July-August. Offshore the pCO(2)(sea) variations with time were relatively small(< 40 mu atm). The pCO(2)(air) shifted by 15 mu atm between the northeast and southwest monsoons. In order to estimate monthly and annual mean of CO, flux in the Arabian Sea, we used sea surface temperature and wi nd speed data, given on a 2.5 degrees x 2.5 degrees resolution, from F NMOC and interpolated the observed pCO(2)(sea) data both in time and s pace. Close to the Omani coast, the estimated monthly mean CO, efflux across the air-sea interface varies from 8.3 to 44 mmol m(-2) month(-1 ) during most of the year and up to 312.8 mmol m(-2) month(-1) during the southwest monsoon season (July/August). Overall, the annual mean C O2 flux from the northern Arabian Sea to the atmosphere is estimated t o be 0.46mol m(-2) yr(-1) or 7.0 Tg Cyr(-1). (C) 1998 Elsevier Science Ltd. All rights reserved.