Sack Lunch Seminar (SLS)

Water Mass Transformation in Shelf Seas



The rate at which water masses are transformed in the shelf seas from one density class to another is assessed in the shelf seas using the Walin (1982) framework. For a tidal-mixing front, the transformation is estimated using air-sea density fluxes and the diapycnal mixing diagnosed from a series of one-dimensional mixed layer models running through the shelf. The transformation rates diagnosed from the air-sea fluxes and diapycnal mixing agrees with volume changes directly diagnosed from the model. This framework is also applied to estimate the rate at which nutrients are converted in nutrient space including the effects of biological consumption. The transformation in density and nutrient space are found to be broadly related in the spring when there is a relatively tight relationship between density and nutrient concentration. Over a larger expanse of the Celtic and Irish shelf seas, the Walin framework is then applied to estimate the transformation of water masses using observed air-sea fluxes and surface isopycnals diagnosed from a combination of remotely-sensed sea surface temperature and cruise sections.