Seasonal variations between sampling and classical mean turbulent heat flux estimates in the North Atlantic
Josey, S. A., Kent, E. C. and Taylor, P. K. (1995) Seasonal variations between sampling and classical mean turbulent heat flux estimates in the North Atlantic. Annales Geophysicae, 13, 10541064.
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Description/Abstract
The two commonly used statistical measures of the airsea heat flux, the sampling and classical means, have been compared using hourly reports over a 7yearperiod from a weather ship stationed in the NE Atlantic. The sampling mean is the average over all flux estimates in a given period, where individual flux estimates are determined from ship reports of meteorological variables using the wellknown bulk formulae. The classical mean is the flux derived by substituting periodaveraged values for each of the meteorological variables into the bulk formula (where the averaging period employed is the same as that over which the fluxes are to be determined). Monthly sampling and classical means are calculated for the latent and sensible heat fluxes. The monthly classical mean latent heat flux is found to overestimate the sampling mean by an amount which increases from 1–2 W m–2 in summer to 7 W m–2 in winter, on average, over the 7yearperiod. In a given winter month, the excess may be as great as 15 W m–2, which represents about 10% of the latent heat flux. For the sensible heat flux, any seasonal variation between the two means is of the order of 1 W m–2 and is not significant compared to the interannual variation. The discrepancy between the two means for the latent heat flux is shown to arise primarily from a negative correlation between the wind speed and seaair humidity difference, the effects of which are implicitly included in the sampling method but not in the classical. The influence of the dominant weather conditions on the sign and magnitude of this correlation are explored, and the large negative values that it takes in winter are found to depend on the typical track of the midlatitude depressions with respect to the position sampled. In conclusion, it is suggested that sampling means should be employed where possible in future climatological studies.
Item Type:  Article  

ISSNs:  09927689 (print) 

Related URLs:  
Keywords:  flux, calculation, averaging, parameterisation, marine meteorology  
Subjects:  G Geography. Anthropology. Recreation > GE Environmental Sciences  
Divisions:  University Structure  Pre August 2011 > National Oceanography Centre (NERC) 

ePrint ID:  55830  
Date : 


Date Deposited:  08 Aug 2008  
Last Modified:  31 Mar 2016 12:36  
URI:  http://eprints.soton.ac.uk/id/eprint/55830 
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