CO₂ exchange coefficients from remotely sensed wind speed measurements: SSM/I versus QuikSCAT in 2000

We compare here the air‐sea exchange coefficient for CO 2 estimated with monthly mean wind speed measured by the Special Sensing Microwave Imager (SSM/I), K S , and by the scatterometer QuikSCAT, K Q , for the year 2000. K S and K Q present the same patterns, although are larger than in ∼65% of the world ocean. Zonal mean K S are consistently larger, except ∼50°S and north of 10°S in the Indian Ocean. Global oceanic uptake, F Q , estimated using K Q and climatological Δp CO 2 ranges from 0.43 (July) to 2.6 Gt C y −1 (December). The global sink estimated from SSM/I is ∼10% larger than F Q for most of the year. This comparison supports the use of SSM/I to quantify interannual variability of the global exchange coefficient of CO 2 .