A new method to measure Bowen ratios using high-resolution vertical dry and wet bulb temperature profiles

Boer-Euser, Tanja de; Luxemburg, W. M. J.; Everson, C. S.; Mengistu, M. G.; Clulow, Alistair D.; Bastiaanssen, W.G.M.

doi:10.5194/hess-18-2021-2014

Cited by 36 publications

(49 citation statements)

References 50 publications

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“…In some installations, there is no restricting upper limit for the diameter of the coil, so use of such large diameter is feasible. For example, the environment of the installation offers sufficient space and the temperature barely varies in lateral direction from the HR-DTS pole, such as in a lake (Vercauteren et al, 2011) or on an open field (Euser et al, 2014). In these cases, the required coil resolution and the machine resolution determine the diameter of the coil, and there is usually no need to apply a coil with a very small diameter.…”

Section: Influence Of Coil Diametermentioning

confidence: 99%

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Practical considerations for enhanced-resolution coil-wrapped distributed temperature sensing

Hilgersom

Emmerik

Solcerová

et al. 2016

Geosci. Instrum. Method. Data Syst.

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Abstract. Fibre optic distributed temperature sensing (DTS) is widely applied in Earth sciences. Many applications require a spatial resolution higher than that provided by the DTS instrument. Measurements at these higher resolutions can be achieved with a fibre optic cable helically wrapped on a cylinder. The effect of the probe construction, such as its material, shape, and diameter, on the performance has been poorly understood. In this article, we study data sets obtained from a laboratory experiment using different cable and construction diameters, and three field experiments using different construction characteristics. This study shows that the construction material, shape, diameter, and cable attachment method can have a significant influence on DTS temperature measurements. We present a qualitative and quantitative approximation of errors introduced through the choice of auxiliary construction, influence of solar radiation, coil diameter, and cable attachment method. Our results provide insight into factors that influence DTS measurements, and we present a number of solutions to minimize these errors. These practical considerations allow designers of future DTS measurement set-ups to improve their environmental temperature measurements.

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Section: Influence Of Coil Diametermentioning

confidence: 99%

“…Vercauteren et al, 2011;Van Emmerik et al, 2013), and in the air (e.g. Thomas et al, 2012;Euser et al, 2014;De Jong et al, 2015).…”

Section: Introductionmentioning

confidence: 99%

Practical considerations for enhanced-resolution coil-wrapped distributed temperature sensing

Hilgersom

Emmerik

Solcerová

et al. 2016

Geosci. Instrum. Method. Data Syst.

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“…There are no reliable and low-cost ground-based ET flux measurement techniques, although new inventions are always underway (Euser et al, 2014). It is simply too costly to install instruments that have the capacity to measure ET operationally at various locations dispersed across a river basin.…”

Section: Accuracy Of Spatial Evapotranspiration Datamentioning

confidence: 99%

Spatial evapotranspiration, rainfall and land use data in water accounting – Part 1: Review of the accuracy of the remote sensing data

Karimi

Bastiaanssen

2015

Hydrol. Earth Syst. Sci.

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128

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Abstract. The scarcity of water encourages scientists to develop new analytical tools to enhance water resource management. Water accounting and distributed hydrological models are examples of such tools. Water accounting needs accurate input data for adequate descriptions of water distribution and water depletion in river basins. Ground-based observatories are decreasing, and not generally accessible. Remote sensing data is a suitable alternative to measure the required input variables. This paper reviews the reliability of remote sensing algorithms to accurately determine the spatial distribution of actual evapotranspiration, rainfall and land use. For our validation we used only those papers that covered study periods of seasonal to annual cycles because the accumulated water balance is the primary concern. Review papers covering shorter periods only (days, weeks) were not included in our review. Our review shows that by using remote sensing, the absolute values of evapotranspiration can be estimated with an overall accuracy of 95 % (SD 5 %) and rainfall with an overall absolute accuracy of 82 % (SD 15 %). Land use can be identified with an overall accuracy of 85 % (SD 7 %). Hence, more scientific work is needed to improve the spatial mapping of rainfall and land use using multiple space-borne sensors. While not always perfect at all spatial and temporal scales, seasonally accumulated actual evapotranspiration maps can be used with confidence in water accounting and hydrological modeling.

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“…First introduced by Euser et al (2014), DTS can also be used for measuring the Bowen ratio, to estimate the evaporation flux. A dry and wet stretch of the same fibre optic cable are installed vertically to obtain the so-called dryand wet-bulb temperature gradient, respectively.…”

mentioning

confidence: 99%

“…Rapid improvements in the precision and spatial resolution of distributed temperature sensing (DTS) technology now allow its use in hydrological and atmospheric sciences. Introduced by Euser et al (2014) is the use of DTS for measuring the Bowen ratio (BR-DTS), to estimate the sensible and latent heat flux. The Bowen ratio is derived from DTS-measured vertical profiles of the air temperature and wet-bulb temperature.…”

mentioning

confidence: 99%

Technical note: Using distributed temperature sensing for Bowen ratio evaporation measurements

Schilperoort

Coenders-Gerrits

Luxemburg

et al. 2018

Hydrol. Earth Syst. Sci.

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Abstract. Rapid improvements in the precision and spatial resolution of distributed temperature sensing (DTS) technology now allow its use in hydrological and atmospheric sciences. Introduced by Euser et al. (2014) is the use of DTS for measuring the Bowen ratio (BR-DTS), to estimate the sensible and latent heat flux. The Bowen ratio is derived from DTS-measured vertical profiles of the air temperature and wet-bulb temperature. However, in previous research the measured temperatures were not validated, and the cables were not shielded from solar radiation. Additionally, the BR-DTS method has not been tested above a forest before, where temperature gradients are small and energy storage in the air column becomes important.In this paper the accuracy of the wet-bulb and air temperature measurements of the DTS are verified, and the resulting Bowen ratio and heat fluxes are compared to eddy covariance data. The performance of BR-DTS was tested on a 46 m high tower in a mixed forest in the centre of the Netherlands in August 2016. The average tree height is 26 to 30 m, and the temperatures are measured below, in, and above the canopy. Using the vertical temperature profiles the storage of latent and sensible heat in the air column was calculated.We found a significant effect of solar radiation on the temperature measurements, leading to a deviation of up to 3 K. By installing screens, the error caused by sunlight is reduced to under 1 K. Wind speed seems to have a minimal effect on the measured wet-bulb temperature, both below and above the canopy. After a simple quality control, the Bowen ratio measured by DTS correlates well with eddy covariance (EC) estimates (r 2 = 0.59). The average energy balance closure between BR-DTS and EC is good, with a mean underestimation of 3.4 W m −2 by the BR-DTS method. However, during daytime the BR-DTS method overestimates the available energy, and during night-time the BR-DTS method estimates the available energy to be more negative. This difference could be related to the biomass heat storage, which is neglected in this study.The BR-DTS method overestimates the latent heat flux on average by 18.7 W m −2 , with RMSE = 90 W m −2 . The sensible heat flux is underestimated on average by 10.6 W m −2 , with RMSE = 76 W m −2 . Estimates of the BR-DTS can be improved once the uncertainties in the energy balance are reduced. However, applying, for example, Monin-Obukhov similarity theory could provide independent estimates for the sensible heat flux. This would make the determination of the highly uncertain and difficult to determine net available energy redundant.

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A new method to measure Bowen ratios using high-resolution vertical dry and wet bulb temperature profiles

Cited by 36 publications

References 50 publications

Practical considerations for enhanced-resolution coil-wrapped distributed temperature sensing

Practical considerations for enhanced-resolution coil-wrapped distributed temperature sensing

Spatial evapotranspiration, rainfall and land use data in water accounting – Part 1: Review of the accuracy of the remote sensing data

Technical note: Using distributed temperature sensing for Bowen ratio evaporation measurements

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