Monitoring volume, heat, and salt transports in the Faroe Current 1993-2013

This report describes the observational material and the methods used to calculate volume, heat, and salt transport of Atlantic inflow to the Nordic Seas in the Faroe Current that passes through section N, extending northwards from the Faroe Shelf. The observational material includes data from regular CTD cruises along this section since the late 1980s and from moored ADCPs since the mid-1990s, as well as altimetry data since 1993. In contrast to previous efforts, the methodology here is based on an integration of the in-situ and the altimetry data. The ADCP observations are used to calibrate the altimetry data, which are then used to generate time series of eastward surface velocity for the whole altimetry period since 1 January 1993. From the ADCP data, vertical profiles of velocity are determined and combined with the altimetric surface velocities to generate time series of the velocity distribution on the section. This allows calculation of volume transport, but to identify the Atlantic water component and to calculate heat and salt transport, time series of temperature and salinity distributions on the section are needed, as well. By comparing data from all the (almost 100) CTD cruises on the section with other observational data, it is found that both temperature and salinity may be simulated with reasonable accuracy from a few observational inputs. This report focuses on the details involved in generating transport time series. The main results are discussed in a separate publication: "Hansen et al.: Increasing transports of volume, heat, and salt towards the Arctic in the Faroe Current 1993-2013", submitted to Ocean Science.