سال انتشار: ۱۳۸۴

محل انتشار: ششمین همایش علوم و فنون دریایی

تعداد صفحات: ۲

نویسنده(ها):

S. Hassanzadeh – Physics Department Isfahan University
D. Alipour – Marine Physics Department Khoramshahe University

چکیده:

Understanding and quantifying upwelling is of great importance for marine resource management. Direct management of this process is extremely difficult and observed time-series do not exist. However, proxies are commonly derived from different data; most commonly wind-derived. Frictional stress of wind on the ocean surface, acting together with the earth’s rotation, causes water flow in the surface layer to deviate to the right in the northern hemisphere and to the left in the southern. .When the direction of the transported water is directly offshore. Water from beneath the surface up wells to replace it. If pumping is strong enough to break the thermo cline, the upwelling waters are normally nutrient-rich and, once in the phonic zone, highly productive. As a result, changes in upwelling over different time-scales, linked to variations in the atmospheric system and water column structure, are related to variability in fish populations and other components of the coastal ocean systems. One possibility is to estimate upwelling by looking at its consequences on common locallymeasured variables such as sea surface temperature (SST) and the structure to the ocean surface as derived from satellite imagery. A second approach is to look at the upwelling forcing agents. From pressure grid data he estimated geostrophic winds, wind stress, and Ekman transport, and presumed perpendicular offshore transport to be proportional to upwelling. Other Ekman transportderived indices have been computed using locally-measured winds by coastal stations and by ships at sea. Locally-measured wind data seems to be an alternative for computing an upwelling index for this region considering the topographically polarized wind circulation.Wind stress for each daily wind value was estimated using: c v v dt = r