Acoustic Tomography of the Atmosphere: Comparison of Different Reconstruction Algorithms

Fischer, Gabi; Barth, Manuela; Ziemann, Astrid

doi:10.3813/aaa.918535

Cited by 16 publications

(13 citation statements)

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“…(6) in advance, thus to predetermine A þ from Eq. (12). As t is obtained by actual measurement, then undetermined coefficient e will be gained from Eq.…”

Section: Temperature Distribution Reconstructionmentioning

confidence: 99%

“…Fortunately, temperature distribution can be reconstructed using appropriate reconstruction algorithm with multiple ultrasonic transducers (including transmitters and receivers) properly installed [10][11][12][14][15][16][17]. Fig.…”

Section: Theoretical Basismentioning

confidence: 99%

“…As an emerging nonintrusive technique, ultrasonic temperature measurement has advantages of wide measuring temperature range, strong environmental adaptability, well real-time and continuous working ability [1,3,[7][8][9][10][11][12][13]. Temperature distribution reconstruction using this technique is an inversion process, which depends greatly on reconstruction algorithm.…”

Section: Introductionmentioning

confidence: 99%

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Ultrasonic temperature distribution reconstruction for circular area based on Markov radial basis approximation and singular value decomposition

et al. 2015

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“…(6) in advance, thus to predetermine A þ from Eq. (12). As t is obtained by actual measurement, then undetermined coefficient e will be gained from Eq.…”

Section: Temperature Distribution Reconstructionmentioning

confidence: 99%

Section: Theoretical Basismentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Ultrasonic temperature distribution reconstruction for circular area based on Markov radial basis approximation and singular value decomposition

et al. 2015

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“…As a result, several inversion techniques were developed and validated regarding 4168 A. Ziemann et al: Line-averaging measurement methods their potential for special applications (Fischer et al, 2012). First joint investigations using A-TOM and optical spectrometers confirmed the suitability of combined line-integrating measurements of GHG exchange between surface and atmosphere Schäfer et al, 2012).…”

Section: Acoustic Travel-time Tomography A-tommentioning

confidence: 99%

Line-averaging measurement methods to estimate the gap in the CO<sub>2</sub> balance closure – possibilities, challenges, and uncertainties

2017

Self Cite

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Abstract. An imbalance of surface energy fluxes using the eddy covariance (EC) method is observed in global measurement networks although all necessary corrections and conversions are applied to the raw data. Mainly during nighttime, advection can occur, resulting in a closing gap that consequently should also affect the CO 2 balances. There is the crucial need for representative concentration and wind data to measure advective fluxes. Ground-based remote sensing techniques are an ideal tool as they provide the spatially representative CO 2 concentration together with wind components within the same voxel structure. For this purpose, the presented SQuAd (Spatially resolved Quantification of the Advection influence on the balance closure of greenhouse gases) approach applies an integrated method combination of acoustic and optical remote sensing. The innovative combination of acoustic travel-time tomography (A-TOM) and open-path Fourier-transform infrared spectroscopy (OP-FTIR) will enable an upscaling and enhancement of EC measurements. OP-FTIR instrumentation offers the significant advantage of real-time simultaneous measurements of lineaveraged concentrations for CO 2 and other greenhouse gases (GHGs). A-TOM is a scalable method to remotely resolve 3-D wind and temperature fields. The paper will give an overview about the proposed SQuAd approach and first results of experimental tests at the FLUXNET site Grillenburg in Germany.Preliminary results of the comprehensive experiments reveal a mean nighttime horizontal advection of CO 2 of about 10 µmol m −2 s −1 estimated by the spatially integrating and representative SQuAd method. Additionally, uncertainties in determining CO 2 concentrations using passive OP-FTIR and wind speed applying A-TOM are systematically quantified. The maximum uncertainty for CO 2 concentration was estimated due to environmental parameters, instrumental characteristics, and retrieval procedure with a total amount of approximately 30 % for a single measurement. Instantaneous wind components can be derived with a maximum uncertainty of 0.3 m s −1 depending on sampling, signal analysis, and environmental influences on sound propagation. Averaging over a period of 30 min, the standard error of the mean values can be decreased by a factor of at least 0.5 for OP-FTIR and 0.1 for A-TOM depending on the required spatial resolution. The presented validation of the joint application of the two independent, nonintrusive methods is in the focus of attention concerning their ability to quantify advective fluxes.

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“…Commonly used least-squares methods, such as direct matrix inversion algorithm, algebraic reconstruction technique (ART), simultaneous iterative reconstruction technique, multiplicative ART [6], require the number of pixels contained in measurement space to be less than that of the paths, which means the temperature fields reconstructed with these methods have a coarser spatial resolution. In this paper, radial basis function approximation and regularization are used in our reconstruction algorithm, which leads to the pixel number of the reconstruction image increasing dramatically.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of Reconstruction Strategies of 3D Temperature Fields for Detecting Hotspots in Grain Bulk

Liu¹,

Yan²,

Zhou³

2018

dtcse

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Abstract.A hotspot in a grain bulk is a localized high temperature zone and normally spoilage begins in this location. The reconstruction strategies of a 3D space are investigated to detect hotspots in grain bulk by acoustic tomography. Since the size of a grain silo is usually large, the whole space to be reconstructed is divided into three blocks and two reconstruction ways: whole reconstruction and block reconstruction, are considered. Three sound ray path selection rules including intra-block, generalized intra-block and unrestricted paths are investigated. These reconstruction ways and path selection rules are combined into four reconstruction strategies. To fully compare the abilities of these strategies in detecting hotspots in grain bulk, 2304 single-hotspot temperature fields and a three-hotspot temperature field are reconstructed by using noise-free and noisy travel-time data. Based on reconstruction results and difficulty in travel-time measurement, the strategy using whole reconstruction way and generalized intra-block paths is the optimal choice.

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Acoustic Tomography of the Atmosphere: Comparison of Different Reconstruction Algorithms

Cited by 16 publications

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Ultrasonic temperature distribution reconstruction for circular area based on Markov radial basis approximation and singular value decomposition

Ultrasonic temperature distribution reconstruction for circular area based on Markov radial basis approximation and singular value decomposition

Line-averaging measurement methods to estimate the gap in the CO<sub>2</sub> balance closure – possibilities, challenges, and uncertainties

Evaluation of Reconstruction Strategies of 3D Temperature Fields for Detecting Hotspots in Grain Bulk

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Acoustic Tomography of the Atmosphere: Comparison of Different Reconstruction Algorithms

Cited by 16 publications

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Ultrasonic temperature distribution reconstruction for circular area based on Markov radial basis approximation and singular value decomposition

Ultrasonic temperature distribution reconstruction for circular area based on Markov radial basis approximation and singular value decomposition

Line-averaging measurement methods to estimate the gap in the CO&lt;sub&gt;2&lt;/sub&gt; balance closure – possibilities, challenges, and uncertainties

Evaluation of Reconstruction Strategies of 3D Temperature Fields for Detecting Hotspots in Grain Bulk

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Line-averaging measurement methods to estimate the gap in the CO<sub>2</sub> balance closure – possibilities, challenges, and uncertainties