ON UPWELLING ALONG A ZONALLY-ORIENTATED COASTLINE.

Abstract

A COMMON OBSERVATION IN MAJOR COASTAL UPWELLING REGIONS IS A REVERSAL OF THE MEAN LONGSHORE CURRENT WITH DEPTH DURING ACTIVE UPWELLING.A NUMERICAL MODEL AND A SIMPLE ANALYTICAL MODEL APPLIED TO A TWO-LAYER OCEAN ON A BETA-PLANE INDICATE THAT THIS UNDERCURRENT CANNOT EXIST FOR UPWELLING OFF AN EAST-WEST (ZONAL) COASTLINE.THE MODELS ARE APPLIED TO THE COASTAL UPWELLING OCCURRING ON THE CAMPECHE BANK DURING THE PERIOD FROM MARCH TO SEPTEMBER.THE BETA-PLANE SOLUTIONS FOR UPWELLING ALONG AN EAST-WEST COASTLINE RESEMBLE F-PLANE SOLUTIONS FOR A MERIDIONAL (N-S) COASTLINE.IN PARTICULAR, THE HYPOTHESIS EXPLAINING THE UNDERCURRENT OF HURLBURT AND THOMPSON CANNOT HOLD FOR UPWELLING ALONG A ZONAL COASTLINE.THE RESULTS IN THIS PAPER FORM A NEW HYPOTHESIS WHICH COULD BE TESTED BY MEASURING CURRENTS ON THE CAMPECHE BANK DURING ACTIVE UPWELLING.(A)