Liverpool Bay

The observations for this scenario have been carried out by Rippeth et al. (2001) in the Liverpool Bay ROFI on July 5 and 6, 1999 at a position of 53$ ^{\circ}$28.4'N, 3$ ^{\circ}$39.2'W. This period is about three days after spring tide, with calm weather and clear sky. The dissipation rate measurements were carried out with a FLY shear probe mounted on a free-falling profiler. Sensors for temperature and conductivity attached to the profiler give detailed information on the vertical density distribution during each cast. Nearby, an ADCP was mounted on the bottom, giving information on the vertical velocity structure. Some accompanying CTD casts were made in order to achieve estimates for the horizontal gradients of temperature and salinity. For further details concerning the observations, see Rippeth et al. (2001).

The surface fluxes are based on ship observations and from a nearby meteorological station at Hawarden. From the ship, wind speed and direction at 10 m above the sea surface and air pressure have been taken. From Hawarden station, observations of dry air, wet bulb and dew point temperature are used. Since the surface fluxes are calculated externally by means of bulk formulae of Kondo (1975), the sea surface temperature from measurements (FLY profiler) has been used. The bed roughness has been estimated from near-bed ADCP measurements as $ z_0^b\approx 0.0025$ m by means of fits to the law of the wall. The external pressure gradient due to surface slopes is estimated according to a method suggested by Burchard (1999) by means of adjustment to near bed velocity observations. The CTD casts carried out during the campaign did only allow for rough estimates of the horizontal density gradient. The horizontal salinity and temperature gradients for a typical summer situation have been estimated by Sharples (1992) to $ \partial_s S=0.0425$ pptkm$ ^{-1}$ and $ \partial_s T=-0.0575$ Kkm$ ^{-1}$, respectively. Here, $ s$ is the gradient into the direction $ \alpha=78^{\circ}$ rotated anti-clockwise from North.

Data files:

sprof.dat salinity in ppt from free-falling shear-probe
tprof.dat potential temperature in $ ^{\circ}$ from free-falling shear-probe
pressure.dat near-bed velocity from ADCP for external pressure forcing
zeta.dat sea surface elevation from pressure gauge
velprof.dat horizontal velocities from bottom mounted ADCP
eprof.dat observed dissipation rates in Wkg$ ^{-1}$
heatflux.dat surface heat fluxes calculated accroding to Kondo (1975)
momentumflux.dat surface momentum fluxes calculated according to Kondo (1975)

The numerical simulations of this scenario has been described in Simpson et al. (2002).

Karsten Bolding 2012-01-24