Revealing the Morning Transition in the Mountain Boundary Layer using Fiber‐Optic Distributed Temperature Sensing

Abstract. A new method for measuring air temperature profiles in the atmospheric boundary layer at high spatial and temporal resolution is presented. The measurements are based on Raman scattering distributed temperature sensing (DTS) with a fiber optic cable attached to a tethered balloon. These data were used to estimate the height of the stable nocturnal boundary layer. The experiment was successfully deployed during a two-day campaign in September 2009, providing evidence that DTS is well suited for this atmospheric application. Observed stable temperature profiles exhibit an exponential shape confirming similarity concepts of the temperature inversion close to the surface. The atmospheric mixing height (MH) was estimated to vary between 5 m and 50 m as a result of the nocturnal boundary layer evolution. This value is in good agreement with the MH derived from concurrent Radon-222 (222Rn) measurements and in previous studies.

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Fiber optic distributed temperature sensing for the determination of the nocturnal atmospheric boundary layer height

Atmospheric Measurement Techniques Discussions ◽

10.5194/amtd-3-2723-2010 ◽

2010 ◽

Vol 3 (3) ◽

pp. 2723-2741 ◽

Cited By ~ 2

Author(s):

C. A. Keller ◽

H. Huwald ◽

M. K. Vollmer ◽

A. Wenger ◽

M. Hill ◽

...

Keyword(s):

Boundary Layer ◽

Atmospheric Boundary Layer ◽

Fiber Optic ◽

Temperature Inversion ◽

Nocturnal Boundary Layer ◽

Temperature Sensing ◽

Temperature Profiles ◽

Distributed Temperature Sensing ◽

Boundary Layer Height

Abstract. A new method for measuring air temperature profiles in the atmospheric boundary layer at high spatial and temporal resolution is presented. The measurements are based on Raman scattering distributed temperature sensing (DTS) with a fiber optic cable attached to a tethered balloon. These data were used to estimate the height of the stable nocturnal boundary layer. The experiment was successfully deployed during a two-day campaign in September 2009, providing evidence that DTS is well suited for this atmospheric application. Observed stable temperature profiles exhibit an exponential shape confirming similarity concepts of the temperature inversion close to the surface. The atmospheric mixing height (MH) was estimated to vary between 5 m and 50 m as a result of the nocturnal boundary layer evolution. This value is in good agreement to the MH derived from concurrent Radon-222 (222Rn) measurements and in previous studies.

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Thermodynamics of a fast-moving Greenlandic outlet glacier revealed by fiber-optic distributed temperature sensing

Science Advances ◽

10.1126/sciadv.abe7136 ◽

2021 ◽

Vol 7 (20) ◽

pp. eabe7136

Author(s):

Robert Law ◽

Poul Christoffersen ◽

Bryn Hubbard ◽

Samuel H. Doyle ◽

Thomas R. Chudley ◽

...

Keyword(s):

Fiber Optic ◽

Basal Layer ◽

Temperature Sensing ◽

Distributed Temperature Sensing ◽

Catchment Scale ◽

Outlet Glacier ◽

Coarse Spatial Resolution ◽

High Vertical Resolution ◽

Fast Motion ◽

Strain Heating

Measurements of ice temperature provide crucial constraints on ice viscosity and the thermodynamic processes occurring within a glacier. However, such measurements are presently limited by a small number of relatively coarse-spatial-resolution borehole records, especially for ice sheets. Here, we advance our understanding of glacier thermodynamics with an exceptionally high-vertical-resolution (~0.65 m), distributed-fiber-optic temperature-sensing profile from a 1043-m borehole drilled to the base of Sermeq Kujalleq (Store Glacier), Greenland. We report substantial but isolated strain heating within interglacial-phase ice at 208 to 242 m depth together with strongly heterogeneous ice deformation in glacial-phase ice below 889 m. We also observe a high-strain interface between glacial- and interglacial-phase ice and a 73-m-thick temperate basal layer, interpreted as locally formed and important for the glacier’s fast motion. These findings demonstrate notable spatial heterogeneity, both vertically and at the catchment scale, in the conditions facilitating the fast motion of marine-terminating glaciers in Greenland.

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Measuring Artificial Recharge with Fiber Optic Distributed Temperature Sensing

Ground Water ◽

10.1111/j.1745-6584.2012.01006.x ◽

2012 ◽

Vol 51 (5) ◽

pp. 670-678 ◽

Cited By ~ 17

Author(s):

Matthew W. Becker ◽

Brian Bauer ◽

Adam Hutchinson

Keyword(s):

Fiber Optic ◽

Artificial Recharge ◽

Temperature Sensing ◽

Distributed Temperature Sensing

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Investigating Taylor’s frozen turbulence hypothesis in the surface layer at an ideal desert field site using fibre-optic distributed temperature sensing

10.5194/dach2022-200 ◽

2021 ◽

Author(s):

Rainer Hilland ◽

Andreas Christen ◽

Roland Vogt

Keyword(s):

Boundary Layer ◽

Sonic Anemometer ◽

Field Work ◽

Field Investigation ◽

Temperature Sensing ◽

Temperature Fields ◽

Fibre Optic ◽

Distributed Temperature Sensing ◽

Plan View ◽

Wide Range

Taylor&#8217;s frozen turbulence hypothesis is the most critical assumption through which time-resolving sensors may be used to derive statistics of the turbulent spatial field. Namely, it relates temporal autocorrelation to spatial correlation via the mean wind speed and is invoked in almost all boundary layer field work. Nevertheless, the conditions and scales over which Taylor&#8217;s hypothesis is valid remain poorly understood in the atmospheric boundary layer. As part of the Namib Turbulence Experiment (NamTEX) campaign in March 2020, a pseudo-3D fibre-optic distributed temperature sensing (DTS) array was installed within a 300 x 300 m area in the Namib desert. The array is X-shaped in plan view and contains 16 measurement heights from 0.45 m to 2.85 m. Fibre-optic sensing provides air temperature measurements at unprecedented spatio-temporal density (0.25 m horizontally, 0.17 m vertically, and 1 Hz) and was coupled with a vertical array of traditional sonic anemometer point measurements to investigate the relationship between spatial and temporal temperature fields. The Namib provides an ideal location for fundamental boundary layer research: homogenous flat surfaces, no vegetation, little moisture, strong solar forcing, regular and repeated clear-sky conditions, and a wide range of atmospheric stabilities. Using the NamTEX DTS array we present the first field investigation of Taylor&#8217;s hypothesis that considers boundary layer stability and is independent of wind direction. A novel method of 2d horizontal cross-correlation between all possible points of a single height of the DTS is employed to produce spatial &#8216;maps&#8217; of the turbulent flow, whose velocity, direction, and size may be tracked through time.

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