URN to cite this document: urn:nbn:de:bvb:703-epub-5136-3
Title data
Lapo, Karl ; Freundorfer, Anita ; Pfister, Lena ; Schneider, Johann ; Selker, John ; Thomas, Christoph:
Distributed observations of wind direction using microstructures attached to actively heated fiber-optic cables.
In: Atmospheric Measurement Techniques.
Vol. 13
(2020)
Issue 3
.
- pp. 1563-1573.
ISSN 1867-8548
DOI der Verlagsversion: https://doi.org/10.5194/amt-13-1563-2020
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Project information
Project title: |
Project's official title Project's id ERC Consolidator Grant DarkMix 724629 Open Access Publizieren No information |
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Project financing: |
Andere European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme |
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Abstract
The weak-wind boundary layer is characterized by turbulent and submesoscale motions that break the assumptions necessary for using traditional eddy covariance observations such as horizontal homogeneity and stationarity, motivating the need for an observational system that allows spatially resolving measurements of atmospheric flows near the surface. Fiber-optic distributed sensing (FODS) potentially opens the door to observing a wide range of atmospheric processes on a spatially distributed basis and to date has been used to resolve the turbulent fields of air temperature and wind speed on scales of seconds and decimeters. Here we report on progress developing a FODS technique for observing spatially distributed wind direction. We affixed microstructures shaped as cones to actively heated fiber-optic cables with opposing orientations to impose directionally sensitive convective heat fluxes from the fiber-optic cable to the air, leading to a difference in sensed temperature that depends on the wind direction. We demonstrate the behavior of a range of microstructure parameters including aspect ratio, spacing, and size and develop a simple deterministic model to explain the temperature differences as a function of wind speed. The mechanism behind the directionally sensitive heat loss is explored using computational fluid dynamics simulations and infrared images of the cone-fiber system. While the results presented here are only relevant for observing wind direction along one dimension, it is an important step towards the ultimate goal of a full three-dimensional, distributed flow sensor.