Improving Observations of Aggregate Snow Cover Properties on MOSAiC by Integrating Repeat Terrestrial Laser Scanning and In-Situ Data

2021 ◽  
Author(s):  
David Clemens-Sewall ◽  
Amy Macfarlane ◽  
Chris Polashenski ◽  
Don Perovich ◽  
Matthias Jaggi ◽  
...  
Keyword(s):  
Spatial Heterogeneity ◽  
Snow Cover ◽  
Material Properties ◽  
Laser Scanning ◽  
Arctic Sea Ice ◽  
Resistance Force ◽  
Vertical Resolution ◽  
Snow Properties ◽  
Measurement Area

<p>The spatial heterogeneity of the snow cover on Arctic sea ice impacts the coupled Ice-Ocean-Atmosphere system. This spatial heterogeneity manifests in both the spatial distribution of snow thickness and the material properties of that snow (e.g. density, specific surface area [SSA], thermal conductivity, salinity, etc). This presents a challenge for observing the aggregate snow cover properties. Most material properties can only be measured in-situ and it is logistically difficult to measure material properties at a large number of sites. Here, we address this challenge by integrating repeat Terrestrial Laser Scan (TLS) data and in-situ observations of snow properties on an area several hundred meters across. We used TLS to map the topography of this area at cm-scale vertical resolution on approximately a biweekly basis throughout the winter during MOSAiC. By comparing successive scans, we map the spatial extent of snow layers as they build up the snow cover. Concurrently, we made in-situ penetration resistance force measurements using a SnowMicroPen (SMP) to quantify the snow properties at sites within the measurement area. These weekly point measurements, with 3mm vertical resolution, provide details of the grain type, snow density and SSA stratigraphy. Combining the TLS and SMP observations enables us to extrapolate the layer-wise properties of the snow cover throughout the measurement area. We examine how consistent snow properties are within layers and use this information to quantify aggregate snow cover properties for the entire region. For example, by integrating SMP-derived density with TLS-derived layers we estimate aggregate change in snow mass for this region for selected periods of the winter.</p>

scholarly journals Cross-Country Assessment of H-SAF Snow Products by Sentinel-2 Imagery Validated against In-Situ Observations and Webcam Photography

Geosciences ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 129 ◽  
Author(s):  
Gaia Piazzi ◽  
Cemal Tanis ◽  
Semih Kuter ◽  
Burak Simsek ◽  
Silvia Puca ◽  
...  
Keyword(s):  
High Resolution ◽  
Snow Cover ◽  
Large Scale ◽  
Complex Topography ◽  
Snow Properties ◽  
High Resolution Imagery ◽  
Wide Range ◽  
Moderate Resolution ◽  
Sentinel 2

Information on snow properties is of critical relevance for a wide range of scientific studies and operational applications, mainly for hydrological purposes. However, the ground-based monitoring of snow dynamics is a challenging task, especially over complex topography and under harsh environmental conditions. Remote sensing is a powerful resource providing snow observations at a large scale. This study addresses the potential of using Sentinel-2 high-resolution imagery to assess moderate-resolution snow products, namely H10—Snow detection (SN-OBS-1) and H12—Effective snow cover (SN-OBS-3) supplied by the Satellite Application Facility on Support to Operational Hydrology and Water Management (H-SAF) project of the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT). With the aim of investigating the reliability of reference data, the consistency of Sentinel-2 observations is evaluated against both in-situ snow measurements and webcam digital imagery. The study area encompasses three different regions, located in Finland, the Italian Alps and Turkey, to comprehensively analyze the selected satellite products over both mountainous and flat areas having different snow seasonality. The results over the winter seasons 2016/17 and 2017/18 show a satisfying agreement between Sentinel-2 data and ground-based observations, both in terms of snow extent and fractional snow cover. H-SAF products prove to be consistent with the high-resolution imagery, especially over flat areas. Indeed, while vegetation only slightly affects the detection of snow cover, the complex topography more strongly impacts product performances.

scholarly journals Impact of measured and simulated tundra snowpack properties on heat transfer

2021 ◽  
Author(s):  
Victoria R. Dutch ◽  
Nick Rutter ◽  
Leanne Wake ◽  
Melody Sandells ◽  
Chris Derksen ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Field Measurements ◽  
Cold Bias ◽  
Vertical Resolution ◽  
Community Land Model ◽  
Snow Properties ◽  
Soil Temperatures ◽  
Snowpack Properties ◽  
Larger Sample

Abstract. Snowpack microstructure controls the transfer of heat to, and the temperature of, the underlying soils. In situ measurements of snow and soil properties from four field campaigns during two different winters (March and November 2018, January and March 2019) were compared to an ensemble of CLM5.0 (Community Land Model) simulations, at Trail Valley Creek, Northwest Territories, Canada. Snow MicroPenetrometer profiles allowed snowpack density and thermal conductivity to be derived at higher vertical resolution (1.25 mm) and a larger sample size (n = 1050) compared to traditional snowpit observations (3 cm vertical resolution; n = 115). Comparing measurements with simulations shows CLM overestimated snow thermal conductivity by a factor of 3, leading to a cold bias in wintertime soil temperatures (RMSE = 5.8 °C). Bias-correction of the simulated thermal conductivity (relative to field measurements) improved simulated soil temperatures (RMSE = 2.1 °C). Multiple linear regression shows the required correction factor is strongly related to snow depth (R2 = 0.77, RMSE = 0.066) particularly early in the winter. Furthermore, CLM simulations did not adequately represent the observed high proportions of depth hoar. Addressing uncertainty in simulated snow properties and the corresponding heat flux is important, as wintertime soil temperatures act as a control on subnivean soil respiration, and hence impact Arctic winter carbon fluxes and budgets.

3-D imaging of cells using a confocal laser scanning microscope and digital image processing

1988 ◽  
Vol 46 ◽  
pp. 96-97
Author(s):  
Thomas M. Jovin ◽  
Michel Robert-Nicoud ◽  
Donna J. Arndt-Jovin ◽  
Thorsten Schormann
Keyword(s):  
Laser Scanning ◽  
Confocal Laser Scanning Microscope ◽  
Laser Scanning Microscopy ◽  
Confocal Laser Scanning ◽  
Confocal Laser ◽  
Scanning Microscope ◽  
Laser Scanning Microscope ◽  
Biochemical Processes ◽  
Adjacent Structures

Light microscopic techniques for visualizing biomolecules and biochemical processes in situ have become indispensable in studies concerning the structural organization of supramolecular assemblies in cells and of processes during the cell cycle, transformation, differentiation, and development. Confocal laser scanning microscopy offers a number of advantages for the in situ localization and quantitation of fluorescence labeled targets and probes: (i) rejection of interfering signals emanating from out-of-focus and adjacent structures, allowing the “optical sectioning” of the specimen and 3-D reconstruction without time consuming deconvolution; (ii) increased spatial resolution; (iii) electronic control of contrast and magnification; (iv) simultanous imaging of the specimen by optical phenomena based on incident, scattered, emitted, and transmitted light; and (v) simultanous use of different fluorescent probes and types of detectors.We currently use a confocal laser scanning microscope CLSM (Zeiss, Oberkochen) equipped with 3-laser excitation (u.v - visible) and confocal optics in the fluorescence mode, as well as a computer-controlled X-Y-Z scanning stage with 0.1 μ resolution.

scholarly journals Time-Response-Histogram-Based Feature of Magnetic Barkhausen Noise for Material Characterization Considering Influences of Grain and Grain Boundary under In Situ Tensile Test

Sensors ◽  
2021 ◽  
Vol 21 (7) ◽  
pp. 2350
Author(s):  
Jia Liu ◽  
Guiyun Tian ◽  
Bin Gao ◽  
Kun Zeng ◽  
Yongbing Xu ◽  
...  
Keyword(s):  
Grain Boundary ◽  
Tensile Stress ◽  
Material Properties ◽  
Ferromagnetic Material ◽  
Silicon Steel ◽  
Time Response ◽  
Barkhausen Noise ◽  
Time Interval ◽  
Magnetic Barkhausen Noise

Stress is the crucial factor of ferromagnetic material failure origin. However, the nondestructive test methods to analyze the ferromagnetic material properties’ inhomogeneity on the microscopic scale with stress have not been obtained so far. In this study, magnetic Barkhausen noise (MBN) signals on different silicon steel sheet locations under in situ tensile tests were detected by a high-spatial-resolution magnetic probe. The domain-wall (DW) motion, grain, and grain boundary were detected using a magneto-optical Kerr (MOKE) image. The time characteristic of DW motion and MBN signals on different locations was varied during elastic deformation. Therefore, a time-response histogram is proposed in this work to show different DW motions inside the grain and around the grain boundary under low tensile stress. In order to separate the variation of magnetic properties affected by the grain and grain boundary under low tensile stress corresponding to MBN excitation, time-division was carried out to extract the root-mean-square (RMS), mean, and peak in the optimized time interval. The time-response histogram of MBN evaluated the silicon steel sheet’s inhomogeneous material properties, and provided a theoretical and experimental reference for ferromagnetic material properties under stress.

scholarly journals Identifying Spatial and Temporal Variations in Concrete Bridges with Ground Penetrating Radar Attributes

2021 ◽  
Vol 13 (9) ◽  
pp. 1846
Author(s):  
Vivek Kumar ◽  
Isabel M. Morris ◽  
Santiago A. Lopez ◽  
Branko Glisic
Keyword(s):  
Compressive Strength ◽  
Ground Penetrating Radar ◽  
Material Properties ◽  
Temporal Variations ◽  
Concrete Bridges ◽  
Spatial And Temporal Variation ◽  
Reflected Waves ◽  
Ground Penetrating ◽  
Over Time

Estimating variations in material properties over space and time is essential for the purposes of structural health monitoring (SHM), mandated inspection, and insurance of civil infrastructure. Properties such as compressive strength evolve over time and are reflective of the overall condition of the aging infrastructure. Concrete structures pose an additional challenge due to the inherent spatial variability of material properties over large length scales. In recent years, nondestructive approaches such as rebound hammer and ultrasonic velocity have been used to determine the in situ material properties of concrete with a focus on the compressive strength. However, these methods require personnel expertise, careful data collection, and high investment. This paper presents a novel approach using ground penetrating radar (GPR) to estimate the variability of in situ material properties over time and space for assessment of concrete bridges. The results show that attributes (or features) of the GPR data such as raw average amplitudes can be used to identify differences in compressive strength across the deck of a concrete bridge. Attributes such as instantaneous amplitudes and intensity of reflected waves are useful in predicting the material properties such as compressive strength, porosity, and density. For compressive strength, one alternative approach of the Maturity Index (MI) was used to estimate the present values and compare with GPR estimated values. The results show that GPR attributes could be successfully used for identifying spatial and temporal variation of concrete properties. Finally, discussions are presented regarding their suitability and limitations for field applications.

INVESTIGATION OF BIAXIAL ELASTIC MODULUS AND CTE OF BaTiO3 FILMS

2009 ◽  
Vol 23 (24) ◽  
pp. 4933-4941
Author(s):  
GUI-FANG HUANG ◽  
WEI-QING HUANG ◽  
LING-LING WANG ◽  
ZHONG XIE ◽  
BING-SUO ZOU ◽  
...  
Keyword(s):  
Elastic Modulus ◽  
Thermal Cycle ◽  
Laser Scanning ◽  
Stress Measurement ◽  
Coefficient Of Thermal Expansion ◽  
Bulk Material ◽  
Good Reliability ◽  
Scanning Method ◽  
As Stress

To develop high-quality film device with good reliability, it is often essential to be able to evaluate the parameters such as stress, the biaxial elastic modulus, and coefficient of thermal expansion (CTE) of film. Based on the stress measurement in situ during the thermal cycle by laser scanning method, two techniques were used to measure the biaxial elastic modulus and CTE of BaTiO 3 films deposited on substrate. The value of the biaxial elastic modulus and CTE for BaTiO 3 films determined from two methods is close, in which the biaxial elastic modulus of BaTiO 3 films is higher than that of corresponding bulk while the CTE of BaTiO 3 films is a little smaller than that of bulk material.

In-situ Observation of Surface Relief Formation and Disappearance during Order-Disorder Transition of Equi-atomic CuAu alloy using Laser Scanning Confocal Microscopy

2004 ◽  
Vol 842 ◽  
Author(s):  
Seiji Miura ◽  
Hiroyuki Okuno ◽  
Kenji Ohkubo ◽  
Tetsuo Mohri
Keyword(s):  
Surface Relief ◽  
Laser Scanning ◽  
Laser Scanning Confocal Microscopy ◽  
Confocal Scanning Laser Microscopy ◽  
Strain Effect ◽  
In Situ Observation ◽  
Stress Effect ◽  
Scanning Confocal Microscopy ◽  
Crystallographic Orientation Relationship

ABSTRACTIn-situ observation of the formation and disappearance of the surface relief associated with the twinning during the order-disorder transitions among CuAu-I (L10), CuAu-II (PAP) and disordered fcc phases was conducted using Confocal Scanning Laser Microscopy equipped with a gold image furnace. The Retro effect was confirmed in poly-crystal samples, however no evidence was found in single-crystal samples. Also observed in poly-crystal samples are that the disordering temperature detected by the disappearing of relieves is different from grain to grain, and that grain boundary cracking alleviates the Retro effect. The observed phenomena were explained based on the crystallographic orientation relationship among grains investigated by FESEM/EBSD in terms of the elastic strain effect around grain boundaries induced by transition. It was confirmed that in each grain the surface relieves correspond to a set of two {011} planes having a <100> axis perpendicular to both planes in common. It was also found that the larger the average strain of two neighboring grains is, the lower the transition temperature. This observation was explained by the stress effect on the stability of a phase.

scholarly journals Influence of Aging on Corrosion Behaviour of the 6061 Cast Aluminium Alloy

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 1821
Author(s):  
Ting He ◽  
Wei Shi ◽  
Song Xiang ◽  
Chaowen Huang ◽  
Ronald G. Ballinger
Keyword(s):  
Aluminium Alloy ◽  
Laser Scanning ◽  
Corrosion Behaviour ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Kelvin Probe ◽  
Force Microscopy ◽  
The Matrix ◽  
6061 Aluminium Alloy

The influence of AlFeSi and Mg2Si phases on corrosion behaviour of the cast 6061 aluminium alloy was investigated. Scanning Kelvin probe force microscopy (SKPFM), electron probe microanalysis (EPMA), and in situ observations by confocal laser scanning microscopy (CLSM) were used. It was found that Mg2Si phases were anodic relative to the matrix and dissolved preferentially without significantly affecting corrosion propagation. The AlFeSi phases’ influence on 6061 aluminium alloy local corrosion was greater than that of the Mg2Si phases. The corroded region width reached five times that of the AlFeSi phase, and the accelerating effect was terminated as the AlFeSi dissolved.

scholarly journals In Situ 3D-Imaging of the Inner Ear Synapses with a Cochlear Implant

Life ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 301
Author(s):  
Kathrin Malfeld ◽  
Nina Armbrecht ◽  
Holger A. Volk ◽  
Thomas Lenarz ◽  
Verena Scheper
Keyword(s):  
Cochlear Implant ◽  
Inner Ear ◽  
Laser Scanning ◽  
3D Imaging ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Sensory Cells ◽  
Residual Hearing ◽  
Preparation Methods

In recent years sensorineural hearing loss was found to affect not exclusively, nor at first, the sensory cells of the inner ear. The sensory cells’ synapses and subsequent neurites are initially damaged. Auditory synaptopathies also play an important role in cochlear implant (CI) care, as they can lead to a loss of physiological hearing in patients with residual hearing. These auditory synaptopathies and in general the cascades of hearing pathologies have been in the focus of research in recent years with the aim to develop more targeted and individually tailored therapeutics. In the current study, a method to examine implanted inner ears of guinea pigs was developed to examine the synapse level. For this purpose, the cochlea is made transparent and scanned with the implant in situ using confocal laser scanning microscopy. Three different preparation methods were compared to enable both an overview image of the cochlea for assessing the CI position and images of the synapses on the same specimen. The best results were achieved by dissection of the bony capsule of the cochlea.

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