Estimation of the transports through the Strait of Gibraltar

An acoustic doppler current profiler (ADCP) is used to measure the currents and estimate the transports over the Camarinal Sill at the Strait of Gibra ltar. The deepest measurements of the ADCP compare well with an underlying conventional current meter. The exchange interface between the Atlantic and the Mediterranean water is defined as the depth of the maximum vertical sh ear. The mean depth of the shear interface is 147 m. The time series of the depth of the interface and the currents are used to estimate the transport s across the Strait. The resulting values are 0.78 Sv for the Atlantic infl ow and - 0.67 Sv for the Mediterranean outflow. The time series of the shea r interface include fortnightly oscillations of 19m. The lime series of the transports are compared with the pressure and sea level difference records across the Strait. Linear multiple regression is used to estimate the (sta tistical) contribution of each parameter on the variation of transports. Th e cross strait sea level difference is well correlated with the Atlantic in flow and accounts for 57% of the variability of the transport records which improves to 78% when the fortnightly and monthly cycles are included in th e linear regression. The Mediterranean outflow is best correlated with the along strait sea level difference which accounts for only 10% of the variab ility of the transport record. Again the addition of the M-sf and the MM cy cles improves the percentage of the variance accounted for to 37%. The loca l, along strait wind component is significantly correlated with, both the A tlantic inflow and the across strait sea level difference. (C) 2000 Elsevie r Science Ltd. All rights reserved.