Vertical temperature gradients in muddy intertidal sediments in the Forth estuary, Scotland’

When exposed at low water, muddy sediments tend to develop less steep vertical subsurface temperature gradients than do sandy beach sediments. Changes in these gradients are rapid during tidal inundation. Measurements of subsurface temperature and atmospheric variables were made from an instrument tower at Skinflats on the extensive intertidal mudflats of the Forth estuary in Scotland. There was a marked seasonal change in the direction and magnitude of gradients. Gra-dients developed at low water were related to antecedent net radiant energy influx at the mud surface and latent heat flux into the atmospheric boundary layer. The relationship between the change in gradient during an incoming tide and the time of high water showed a well-defined association. Steep vertical temperature gradients may develop within shallow near-surface layers of intertidal sediments when they are ex-posed to the atmosphere at low water. The temperature profiles, which result primaril