Aircraft-based observations of air-sea turbulent fluxes around the British Isles:Observations of Air-Sea Fluxes

Cook, Peter A. and Renfrew, Ian A. (2015) Aircraft-based observations of air-sea turbulent fluxes around the British Isles:Observations of Air-Sea Fluxes. Quarterly Journal of the Royal Meteorological Society, 141 (686). 139–152. ISSN 0035-9009

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Abstract

Observations of turbulent fluxes of momentum, heat and moisture from low-level aircraft data are presented. Fluxes are calculated using the eddy covariance technique from flight legs typically ∼40 m above the sea surface. Over 400 runs of 2 min (∼12 km) from 26 flights are evaluated. Flight legs are mainly from around the British Isles although a small number are from around Iceland and Norway. Sea-surface temperature (SST) observations from two on-board sensors (the ARIES interferometer and a Heimann radiometer) and a satellite-based analysis (OSTIA) are used to determine an improved SST estimate. Most of the observations are from moderate to strong wind speed conditions, the latter being a regime short of validation data for the bulk flux algorithms that are necessary for numerical weather prediction and climate models. Observations from both statically stable and unstable atmospheric boundary-layer conditions are presented. There is a particular focus on several flights made as part of the DIAMET (Diabatic influence on mesoscale structures in extratropical storms) project. Observed neutral exchange coefficients are in the same range as previous studies, although higher for the momentum coefficient, and are broadly consistent with the COARE 3.0 bulk flux algorithm, as well as the surface exchange schemes used in the ECMWF and Met Office models. Examining the results as a function of aircraft heading shows higher fluxes and exchange coefficients in the across-wind direction, compared to along-wind (although this comparison is limited by the relatively small number of along-wind legs). A multi-resolution spectral decomposition technique demonstrates a lengthening of spatial scales in along-wind variances in along-wind legs, implying the boundary-layer eddies are elongated in the along-wind direction. The along-wind runs may not be able to adequately capture the full range of turbulent exchange that is occurring because elongation places the largest eddies outside of the run length.

Item Type: Article
Additional Information: © 2014 The Authors. Quarterly Journal of the Royal Meteorological Society published by JohnWiley & Sons Ltd on behalf of the Royal Meteorological Society. This is an open access article under the terms of the Creative Commons Attribution 4.0 License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
Uncontrolled Keywords: surface turbulent fluxes,exchange coefficients,aircraft observations,boundary-layer turbulence,diamet
Faculty \ School: Faculty of Science > School of Environmental Sciences
Depositing User: Pure Connector
Date Deposited: 04 Jul 2014 12:38
Last Modified: 19 Mar 2020 02:27
URI: https://ueaeprints.uea.ac.uk/id/eprint/48722
DOI: 10.1002/qj.2345

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