Observations of Atmospheric Structure and Dynamics in the Owens Valley of California with a Ground-Based, Eye-Safe, Scanning Aerosol Lidar*

2009 ◽  
Vol 48 (7) ◽  
pp. 1483-1499 ◽  
Author(s):  
Stephan F. J. De Wekker ◽  
Shane D. Mayor
Keyword(s):  
Cross Sections ◽  
Time Lapse ◽  
Breaking Waves ◽  
Mountain Range ◽  
Owens Valley ◽  
Atmospheric Flows ◽  
Drainage Flows ◽  
Rotor Experiment ◽  
First Results ◽  
Atmospheric Phenomena

Abstract First results are presented from the deployment of the NCAR Raman-Shifted Eye-Safe Aerosol Lidar (REAL) in the Owens Valley of California during the Terrain-Induced Rotor Experiment (T-REX) in March and April 2006. REAL operated in range–height indicator (RHI) and plan position indicator (PPI) scanning modes to observe the vertical and horizontal structures of the aerosol and cloud distribution in a broad valley in the lee of a tall mountain range. The scans produce two-dimensional cross sections that when animated produce time-lapse visualizations of the microscale and mesoscale atmospheric structures and dynamics. The 2-month dataset includes a wide variety of interesting atmospheric phenomena. When the synoptic-scale flow is strong and westerly, the lidar data reveal mountain-induced waves, hydraulic jumps, and rotorlike circulations that lift aerosols to altitudes of more than 2 km above the valley. Shear instabilities occasionally leading to breaking waves were observed in cloud and aerosol layers under high wind conditions. In quiescent conditions, the data show multiple aerosol layers, upslope flows, and drainage flows interacting with valley flows. The results demonstrate that a rapidly scanning, eye-safe, ground-based aerosol lidar can be used to observe important features of clear-air atmospheric flows and can contribute to an improved understanding of mountain-induced meteorological phenomena. The research community is encouraged to use the dataset in support of their observational analysis and modeling efforts.

scholarly journals High-Resolution Simulations of Lee Waves and Downslope Winds over the Sierra Nevada during T-REX IOP 6

2012 ◽  
Vol 51 (7) ◽  
pp. 1333-1352 ◽  
Author(s):  
Peter Sheridan ◽  
Simon Vosper
Keyword(s):  
High Resolution ◽  
Sierra Nevada ◽  
Cross Sections ◽  
Weather Prediction ◽  
Vertical Motion ◽  
Owens Valley ◽  
Downslope Winds ◽  
Lee Waves ◽  
Rotor Experiment ◽  
Intensive Observation

AbstractThe downslope windstorm during intensive observation period (IOP) 6 was the most severe that was detected during the Terrain-Induced Rotor Experiment (T-REX) in Owens Valley in the Sierra Nevada of California. Cross sections of vertical motion in the form of a composite constructed from aircraft data spanning the depth of the troposphere are used to link the winds experienced at the surface to the changing structure of the mountain-wave field aloft. Detailed analysis of other observations allows the role played by a passing occluded front, associated with the rapid intensification (and subsequent cessation) of the windstorm, to be studied. High-resolution, nested modeling using the Met Office Unified Model (MetUM) is used to study qualitative aspects of the flow and the influence of the front, and this modeling suggests that accurate forecasting of the timing and position of both the front and strong mountaintop winds is crucial to capture the wave dynamics and accompanying windstorm. Meanwhile, far ahead of the front, simulated downslope winds are shallow and foehnlike, driven by the thermal contrast between the upstream and valley air mass. The study also highlights the difficulties of capturing the detailed interaction of weather systems with large and complex orography in numerical weather prediction.

scholarly journals Magnetotelluric study in the Los Lagos Region (Chile) to investigate volcano-tectonic processes in the Southern Andes

2021 ◽  
Vol 73 (1) ◽  
Author(s):  
Maria Jose Segovia ◽  
Daniel Diaz ◽  
Katarzyna Slezak ◽  
Felipe Zuñiga
Keyword(s):  
Electrical Resistivity ◽  
Three Dimensional ◽  
Phase Changes ◽  
Fault System ◽  
Electrical Anisotropy ◽  
Mountain Range ◽  
Southern Andes ◽  
Nazca Plate ◽  
First Results ◽  
Dimensional Parameters

AbstractTo analyze the process of subduction of the Nazca and South American plates in the area of the Southern Andes, and its relationship with the tectonic and volcanic regime of the place, magnetotelluric measurements were made through a transversal profile of the Chilean continental margin. The data-processing stage included the analysis of dimensional parameters, which as first results showed a three-dimensional environment for periods less than 1 s and two-dimensional for periods greater than 10 s. In addition, through the geomagnetic transfer function (tipper), the presence of structural electrical anisotropy was identified in the data. After the dimensional analysis, a deep electrical resistivity image was obtained by inverting a 2D and a 3D model. Surface conductive anomalies were obtained beneath the central depression related to the early dehydration of the slab and the serpentinization process of the mantle that coincides in location with a discontinuity in the electrical resistivity of a regional body that we identified as the Nazca plate. A shallow conductive body was located around the Calbuco volcano and was correlated with a magmatic chamber or reservoir which in turn appears to be connected to the Liquiñe Ofqui fault system and the Andean Transverse Fault system. In addition to the serpentinization process, when the oceanic crust reaches a depth of 80–100 km, the ascending fluids produced by the dehydration and phase changes of the minerals present in the oceanic plate produce basaltic melts in the wedge of the subcontinental mantle that give rise to an eclogitization process and this explains a large conductivity anomaly present beneath the main mountain range.

scholarly journals Revealing glacier flow and surge dynamics from animated satellite image sequences: examples from the Karakoram

2015 ◽  
Vol 9 (2) ◽  
pp. 2597-2623 ◽  
Author(s):  
F. Paul
Keyword(s):  
Satellite Images ◽  
Satellite Image ◽  
Time Lapse ◽  
Image Sequences ◽  
Flow Dynamics ◽  
Mountain Range ◽  
Time Period ◽  
Climatic Control ◽  
Long Time ◽  
Glacier Flow

Abstract. Although animated images are very popular on the Internet, they have so far found only limited use for glaciological applications. With long time-series of satellite images becoming increasingly available and glaciers being well recognized for their rapid changes and variable flow dynamics, animated sequences of multiple satellite images reveal glacier dynamics in a time-lapse mode, making the otherwise slow changes of glacier movement visible and understandable for a wide public. For this study animated image sequences were created from freely available image quick-looks of orthorectified Landsat scenes for four regions in the central Karakoram mountain range. The animations play automatically in a web-browser and might help to demonstrate glacier flow dynamics for educational purposes. The animations revealed highly complex patterns of glacier flow and surge dynamics over a 15-year time period (1998–2013). In contrast to other regions, surging glaciers in the Karakoram are often small (around 10 km2), steep, debris free, and advance for several years at comparably low annual rates (a few hundred m a−1). The advance periods of individual glaciers are generally out of phase, indicating a limited climatic control on their dynamics. On the other hand, nearly all other glaciers in the region are either stable or slightly advancing, indicating balanced or even positive mass budgets over the past few years to decades.

Fault System Evolution and Its Influences on Buried-hills Formation in Tanhai Area of Jiyang Depression, Bohai Bay Basin, China

2020 ◽  
Author(s):  
Meng Zhang ◽  
Zhiping Wu ◽  
Shiyong Yan
Keyword(s):  
Stress Field ◽  
Cross Sections ◽  
Large Scale ◽  
Structural Evolution ◽  
Fault System ◽  
Mountain Range ◽  
Bohai Bay ◽  
Thrust Faults ◽  
Bohai Bay Basin ◽  
Jiyang Depression

<p>Buried-hills, paleotopographic highs covered by younger sediments, become the focused area of exploration in China in pace with the reduction of hydrocarbon resources in the shallow strata. A number of buried-hill fields have been discovered in Tanhai area located in the northeast of Jiyang Depression within Bohai Bay Basin, which provides an excellent case study for better understanding the structural evolution and formation mechanism of buried-hills. High-quality 3-D seismic data calibrated by well data makes it possible to research deeply buried erosional remnants. In this study, 3-D visualization of key interfaces, seismic cross-sections, fault polygons maps and thickness isopach maps are shown to manifest structural characteristics of buried-hills. Balanced cross-sections and fault growth rates are exhibited to demonstrate the forming process of buried-hills. The initiation and development of buried-hills are under the control of fault system. According to strike variance, main faults are grouped into NW-, NNE- and near E-trending faults. NW-trending main faults directly dominate the whole mountain range, while NNE- and near E-trending main faults have an effect on dissecting mountain range and controlling the single hill. In addition, secondary faults with different nature complicate internal structure of buried-hills. During Late Triassic, NW-trending thrust faults formed in response to regional compressional stress field, preliminarily building the fundamental NW-trending structural framework. Until Late Jurassic-Early Cretaceous, rolling-back subduction of Pacific Plate and sinistral movement of Tan-Lu Fault Zone (TLFZ) integrally converted NW-trending thrust faults into normal faults. The footwall of NW-trending faults quickly rose and became a large-scale NW-trending mountain range. The intense movement of TLFZ simultaneously induced a series of secondary NNE-trending strike-slip faults, among which large-scale ones divided the mountain range into northern, middle and southern section. After entry into Cenozoic, especially Middle Eocene, the change of subduction direction of Pacific Plate induced the transition of regional stress field. Near E-trending basin-controlling faults developed and dissected previous tectonic framework. The middle section of mountain range was further separated into three different single hill. Subsequently, the mountain range was gradually submerged and buried by overlying sediments, due to regional thermal subsidence. Through multiphase structural evolution, the present-day geometry of buried-hills is eventually taken shape.</p>

Magnitude estimation of a landslide-triggered debris flow in the Serra do Mar Mountain Range, Brazil

2020 ◽  
Author(s):  
Victor Carvalho Cabral ◽  
Fernando Mazo D'Affonseca ◽  
Marcelo Fischer Gramani ◽  
Agostinho Tadashi Ogura ◽  
Claudia Santos Corrêa ◽  
...  
Keyword(s):  
Debris Flow ◽  
Magnitude Estimation ◽  
Cross Sections ◽  
Debris Flows ◽  
Mountain Range ◽  
Serra Do Mar ◽  
Solids Concentration ◽  
Geomorphic Features ◽  
Total Magnitude ◽  
Future Events

<p><span>Debris flows represent great hazard to communities and infrastructures, since they move quickly and are very destructive. In Brazil, debris flows mainly occur in the Serra do Mar Mountain Range, where thousands of casualties were reported in the last two decades due to these phenomena. This study aims at estimating the magnitude of a debris-flow event that occurred in Serra do Mar on February 2017, at the Pedra Branca watershed in the State of Paraná. Debris-flow magnitude refers to the volume of material discharged during an event and is an important aspect of debris-flow hazard assessment. The Pedra Branca event was initiated by rainfall-triggered shallow landslides, damaging local oil pipelines and farms. The magnitude estimation is based on the combination of empirically based equations and the geomorphic features of the debris flow, acquired from <em>in situ</em> and aerial investigation. 28 cross-sections were made along the river channel, considering post-event channel width, erosion and accumulation depth, as well as depositional features. Sediment sources and accumulation areas were identified and delimitated based on high-resolution (1:500) aerial drone photographs. The results indicate that the landslides that initiated the event released approximately 26,884.5 m<sup>3</sup> of sediments (V<sub>i</sub>) into the main channel of Pedra Branca and that the volume eroded (V<sub>e</sub>) and accumulated (V<sub>d</sub>) along the channel are, respectively, 82,439 m<sup>3</sup> and 22,012 m<sup>3</sup>. The estimated total solids volume (V<sub>s</sub>) is 87,274 m<sup>3</sup>, assuming that V<sub>s</sub> = V<sub>i</sub> + V<sub>e</sub> - V<sub>d</sub>. Moreover, considering a solids concentration of 57% calculated according to empirically-based equations for Serra do Mar, the debris flow had a total magnitude of 153,113 m<sup>3</sup>. These estimations suggest that the February 2017 debris flow mobilised great volume of material and that 15% of the total volume accumulated on the channel bed, which can be remobilised by future events. Further research on debris-flow dynamics and recurrence at the Serra do Mar Mountain Range is recommended to mitigate future hazards.</span></p>

Turbulence Characteristics in an Elevated Shear Layer over Owens Valley

2010 ◽  
Vol 67 (7) ◽  
pp. 2355-2371 ◽  
Author(s):  
Qingfang Jiang ◽  
James D. Doyle ◽  
Vanda Grubišić ◽  
Ronald B. Smith
Keyword(s):  
Shear Layer ◽  
Energy Cascade ◽  
Inertial Subrange ◽  
Turbulence Energy ◽  
Owens Valley ◽  
Turbulent Layer ◽  
Aspect Ratios ◽  
Rotor Experiment ◽  
Large Eddies

Abstract Characteristics of turbulence in the lower and middle troposphere over Owens Valley have been examined using aircraft in situ measurements obtained from the Terrain-Induced Rotor Experiment. The two events analyzed in this study are characterized by a deep turbulent layer from the valley floor up to the midtroposphere associated with the interaction between trapped waves and an elevated shear layer. Kelvin–Helmholtz (KH) instability develops above the mountaintop level and often along the wave crests where the Richardson number is reduced. The turbulence induced by KH instability is characterized by a progressive downscale energy cascade, a well-defined inertial subrange up to 1 km, and large eddies with vertical to horizontal aspect ratios less than unity. The turbulence below the mountaintop level is largely shear induced, associated with wave steepening and breaking, and is more isotropic. Evaluation of structure functions indicates that while the turbulence energy cascade is predominately downscale, upscale energy transfer exists with horizontal scales from a few hundred meters to a few kilometers because of the transient energy dispersion of large eddies generated by KH instability and gravity wave steepening or breaking.

scholarly journals Retrieval of three-dimensional small-scale structures in upper-tropospheric/lower-stratospheric composition as measured by GLORIA

2015 ◽  
Vol 8 (1) ◽  
pp. 81-95 ◽  
Author(s):  
M. Kaufmann ◽  
J. Blank ◽  
T. Guggenmoser ◽  
J. Ungermann ◽  
A. Engel ◽  
...  
Keyword(s):  
Spatial Resolution ◽  
Cross Sections ◽  
Lower Stratosphere ◽  
Three Dimensional ◽  
Small Scale ◽  
Flight Pattern ◽  
Upper Troposphere ◽  
In Situ Data ◽  
Very High Spatial Resolution ◽  
First Results

Abstract. The three-dimensional quantification of small-scale processes in the upper troposphere and lower stratosphere is one of the challenges of current atmospheric research and requires the development of new measurement strategies. This work presents the first results from the newly developed Gimballed Limb Observer for Radiance Imaging of the Atmosphere (GLORIA) obtained during the ESSenCe (ESa Sounder Campaign) and TACTS/ESMVal (TACTS: Transport and composition in the upper troposphere/lowermost stratosphere, ESMVal: Earth System Model Validation) aircraft campaigns. The focus of this work is on the so-called dynamics-mode data characterized by a medium-spectral and a very-high-spatial resolution. The retrieval strategy for the derivation of two- and three-dimensional constituent fields in the upper troposphere and lower stratosphere is presented. Uncertainties of the main retrieval targets (temperature, O3, HNO3, and CFC-12) and their spatial resolution are discussed. During ESSenCe, high-resolution two-dimensional cross-sections have been obtained. Comparisons to collocated remote-sensing and in situ data indicate a good agreement between the data sets. During TACTS/ESMVal, a tomographic flight pattern to sense an intrusion of stratospheric air deep into the troposphere was performed. It was possible to reconstruct this filament at an unprecedented spatial resolution of better than 500 m vertically and 20 × 20 km horizontally.

scholarly journals Diurnal Variation of Downslope Winds in Owens Valley during the Sierra Rotor Experiment

2008 ◽  
Vol 136 (10) ◽  
pp. 3760-3780 ◽  
Author(s):  
Qingfang Jiang ◽  
James D. Doyle
Keyword(s):  
Diurnal Variation ◽  
Numerical Simulations ◽  
Western Slope ◽  
Owens Valley ◽  
Mountain Waves ◽  
Downslope Winds ◽  
Wind Event ◽  
Downslope Wind ◽  
Rotor Experiment ◽  
The Impact

The impact of diurnal forcing on a downslope wind event that occurred in Owens Valley in California during the Sierra Rotors Project (SRP) in the spring of 2004 has been examined based on observational analysis and diagnosis of numerical simulations. The observations indicate that while the upstream flow was characterized by persistent westerlies at and above the mountaintop level the cross-valley winds in Owens Valley exhibited strong diurnal variation. The numerical simulations using the Coupled Ocean–Atmosphere Mesoscale Prediction System (COAMPS) capture many of the observed salient features and indicate that the in-valley flow evolved among three states during a diurnal cycle. Before sunrise, moderate downslope winds were confined to the western slope of Owens Valley (shallow penetration state). Surface heating after sunrise weakened the downslope winds and mountain waves and eventually led to the decoupling of the well-mixed valley air from the westerlies aloft around local noon (decoupled state). The westerlies plunged into the valley in the afternoon and propagated across the valley floor (in-valley westerly state). After sunset, the westerlies within the valley retreated toward the western slope, where the downslope winds persisted throughout the night.

scholarly journals Magnetoteluric Study in the Region De Los Lagos to Study Volcano-Tectonic Processes in the Southern Andes

2020 ◽  
Author(s):  
Maria Jose Segovia Baldovino ◽  
Daniel Diaz Alvarado ◽  
Katarzyna Slezak ◽  
Felipe Zuñiga Armijo
Keyword(s):  
Electrical Resistivity ◽  
Three Dimensional ◽  
Phase Changes ◽  
Fault System ◽  
Electrical Anisotropy ◽  
Mountain Range ◽  
Southern Andes ◽  
Nazca Plate ◽  
First Results ◽  
Dimensional Parameters

Abstract In order to analyze the process of subduction of the Nazca and South American plates in the area of the Southern Andes, and its relationship with the tectonic and volcanic regime of the place, magnetotelluric measurements were made through a transversal profile of the Chilean continental margin. The data processing stage included the analysis of dimensional parameters, which as first results showed a three-dimensional environment for periods less than 1s and two-dimensional for periods greater than 10s. In addition, through the geomagnetic transfer function (tipper), the presence of structural electrical anisotropy was identified in the data. After the dimensional analysis, a deep electrical resistivity image was obtained by inverting a 2D and a 3D model. Surface conductive anomalies were obtained beneath the central depression related to the early dehydration of the slab and the serpentinization process of the mantle that coincides in location with a discontinuity in the electrical resistivity of a regional body that we identified as the Nazca plate. A shallow conductive body was located around the Calbuco volcano and was correlated with a magmatic chamber or reservoir which in turn appears to be connected to the Liquiñe Ofqui fault system and the Andean Transverse Fault system. In addition to the serpentinization process, when the oceanic crust reaches a depth of 80-100km, the ascending fluids produced by the dehydration and phase changes of the minerals present in the oceanic plate produce basaltic melts in the wedge of the subcontinental mantle that give rise to an eclogitization process and this explains a large conductivity anomaly present beneath the main mountain range.

scholarly journals Using Time Lapse Monitoring for Determination of Morphological Defect Frequency in Feline Embryos after in Vitro Fertilization (IVF)

Animals ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 3 ◽  
Author(s):  
Barbara Kij ◽  
Joanna Kochan ◽  
Agnieszka Nowak ◽  
Wojciech Niżański ◽  
Sylwia Prochowska ◽  
...  
Keyword(s):  
Time Lapse ◽  
Blastocyst Stage ◽  
Hatching Rate ◽  
Vitro Fertilization ◽  
First Results ◽  
Morphological Defects ◽  
Defect Frequency ◽  
Selection Of

Some human, bovine, and mouse in vitro fertilized (IVF) embryos with morphokinetic abnormalities such as fragmentation, direct cleavage, and cytoplasmic vacuoles have the potential to reach the blastocyst stage, which is related to a high potential for implantation. The latest techniques of embryo development observation to enable the evaluation and selection of embryos are based on time lapse monitoring (TLM). The aim of this study was to determine the frequency of morphological defects in feline embryos, their competence to reach the blastocyst stage, and their ability to hatch. Oocyte-cumulus complexes were isolated after the scarification of ovaries and matured in vitro. Matured oocytes were fertilized in vitro by capacitated spermatozoa. Randomly selected oocytes were observed by TLM for seven-to-eight days. Out of 76 developed embryos, 41 were morphologically normal, of which 15 reached the blastocyst stage. Of 35 abnormally developed embryos, 17 reached the blastocyst stage, of which six had single aberrations and 11 had multiple aberrations. The hatching rate (%) was 15.6% in normally cleaving embryos, 6.25% in embryos with single aberrations, and 3.33% in those with multiple aberrations. The present study reports the first results, found by using TLM, about the frequency of the morphological defects of feline embryos, their competence to reach the blastocyst stage, and their ability to hatch.

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