scholarly journals QCam: sUAS-Based Doppler Radar for Measuring River Discharge

2020 ◽  
Vol 12 (20) ◽  
pp. 3317
Author(s):  
John W. Fulton ◽  
Isaac E. Anderson ◽  
C.-L. Chiu ◽  
Wolfram Sommer ◽  
Josip D. Adams ◽  
...  
Keyword(s):  
Remote Sensing ◽  
High Altitude ◽  
River Discharge ◽  
Near Field ◽  
Surface Velocity ◽  
Sectional Area ◽  
Mean Velocity ◽  
Cross Sectional ◽  
Arkansas River ◽  
South Platte River

The U.S. Geological Survey is actively investigating remote sensing of surface velocity and river discharge (discharge) from satellite-, high altitude-, small, unmanned aircraft systems- (sUAS or drone), and permanent (fixed) deployments. This initiative is important in ungaged basins and river reaches that lack the infrastructure to deploy conventional streamgaging equipment. By coupling alternative discharge algorithms with sensors capable of measuring surface velocity, streamgage networks can be established in regions where data collection was previously impractical or impossible. To differentiate from satellite or high-altitude platforms, near-field remote sensing is conducted from sUAS or fixed platforms. QCam is a Doppler (velocity) radar mounted and integrated on a 3DR© Solo sUAS. It measures the along-track surface velocity by spot dwelling in a river cross section at a vertical where the maximum surface velocity is recorded. The surface velocity is translated to a mean-channel (mean) velocity using the probability concept (PC), and discharge is computed using the PC-derived mean velocity and cross-sectional area. Factors including surface-scatterer quality, flight altitude, propwash, wind drift, and sample duration may affect the radar-returns and the subsequent computation of mean velocity and river discharge. To evaluate the extensibility of the method, five science flights were conducted on four rivers of varying size and dynamics and included the Arkansas River, Colorado (CO), USA (two events); Salcha River near Salchaket, Alaska (AK), USA; South Platte River, CO, USA; and the Tanana River, AK, USA. QCam surface velocities and river discharges were compared to conventional streamgaging methods, which represented truth. QCam surface velocities for the Arkansas River, Salcha River, South Platte River, and Tanana River were 1.02 meters per second (m/s) and 1.43 m/s; 1.58 m/s; 0.90 m/s; and 2.17 m/s, respectively. QCam discharges (and percent differences) were 9.48 (0.3%) and 20.3 cubic meters per second (m3/s) (2.5%); 62.1 m3/s (−10.4%); 3.42 m3/s (7.3%), and 1579 m3/s (−18.8%). QCam results compare favorably with conventional streamgaging and are a viable near-field remote sensing technology that can be operationalized to deliver real-time surface velocity, mean velocity, and river discharge, if cross-sectional area is available.

scholarly journals Near-Field Remote Sensing of Surface Velocity and River Discharge Using Radars and the Probability Concept at 10 U.S. Geological Survey Streamgages

2020 ◽  
Vol 12 (8) ◽  
pp. 1296 ◽  
Author(s):  
John W. Fulton ◽  
Christopher A. Mason ◽  
John R. Eggleston ◽  
Matthew J. Nicotra ◽  
Chao-Lin Chiu ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Time Series ◽  
Real Time ◽  
River Discharge ◽  
Near Field ◽  
Geological Survey ◽  
Surface Velocity ◽  
Mean Velocity ◽  
Probability Concept ◽  
Conventional Methods

Near-field remote sensing of surface velocity and river discharge (discharge) were measured using coherent, continuous wave Doppler and pulsed radars. Traditional streamgaging requires sensors be deployed in the water column; however, near-field remote sensing has the potential to transform streamgaging operations through non-contact methods in the U.S. Geological Survey (USGS) and other agencies around the world. To differentiate from satellite or high-altitude platforms, near-field remote sensing is conducted from fixed platforms such as bridges and cable stays. Radar gages were collocated with 10 USGS streamgages in river reaches of varying hydrologic and hydraulic characteristics, where basin size ranged from 381 to 66,200 square kilometers. Radar-derived mean-channel (mean) velocity and discharge were computed using the probability concept and were compared to conventional instantaneous measurements and time series. To test the efficacy of near-field methods, radars were deployed for extended periods of time to capture a range of hydraulic conditions and environmental factors. During the operational phase, continuous time series of surface velocity, radar-derived discharge, and stage-discharge were recorded, computed, and transmitted contemporaneously and continuously in real time every 5 to 15 min. Minimum and maximum surface velocities ranged from 0.30 to 3.84 m per second (m/s); minimum and maximum radar-derived discharges ranged from 0.17 to 4890 cubic meters per second (m3/s); and minimum and maximum stage-discharge ranged from 0.12 to 4950 m3/s. Comparisons between radar and stage-discharge time series were evaluated using goodness-of-fit statistics, which provided a measure of the utility of the probability concept to compute discharge from a singular surface velocity and cross-sectional area relative to conventional methods. Mean velocity and discharge data indicate that velocity radars are highly correlated with conventional methods and are a viable near-field remote sensing technology that can be operationalized to deliver real-time surface velocity, mean velocity, and discharge.

scholarly journals Analysis of a Converging, Annular, Isothermal Melt Blowing Jet Using Computational Fluid Dynamics

2005 ◽  
Vol os-14 (3) ◽  
pp. 1558925005os-14
Author(s):  
Eric M. Moore ◽  
Dimitrios V. Papavassiliou ◽  
Robert L. Shambaugh
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Kinetic Energy ◽  
Near Field ◽  
Flow Characteristics ◽  
Sectional Area ◽  
Melt Blowing ◽  
Mean Velocity ◽  
Cross Sectional ◽  
Computational Fluid Dynamics Cfd

An unconventional melt blowing die was analyzed using computational fluid dynamics (CFD). This die has an annular configuration wherein the jet inlet is tapered (the cross-sectional area decreases) as the air approaches the die face. It was found that the flow characteristics of this die are different from conventional slot and annular dies. In particular, for the tapered die the near-field normalized turbulent kinetic energy was found to be lower at shallow die angles. Also, it was found that the peak mean velocity behavior was intermediate between that of conventional annular and slot dies. The centerline turbulence profiles were found to be qualitatively similar to those of annular dies; quantitatively, higher values were present for tapered dies.

Uncertainties in the single determination of river discharge: a literature review

1988 ◽  
Vol 15 (5) ◽  
pp. 834-850 ◽  
Author(s):  
Patrice M. Pelletier
Keyword(s):  
Literature Review ◽  
River Discharge ◽  
Mean Velocity ◽  
Cross Sectional ◽  
Area Method ◽  
Small Streams ◽  
Ice Conditions ◽  
Single Determination ◽  
Available Information

This paper presents the results of a literature review of more than 140 publications on the uncertainties in the determination of river discharge. The uncertainties in a single determination of discharge, which includes uncertainties in sampling the cross-sectional area and the mean velocity in time and in space and uncertainties in the current meter, are emphasized. The objectives of the literature review were to determine all the possible sources of uncertainties in a current meter measurement, to quantify these uncertainties based on past investigations, and to determine if additional research was required to improve the overall accuracy of hydrometric data in Canada. Because of lack of available information on the performance of the current meter in combination with the velocity–area method under conditions of small streams or low velocities, research is required. Research is also required to assess the uncertainties in the determination of discharge under ice conditions. Key words: accuracy, current meter, error, hydrometric data, river discharge, uncertainty, velocity–area method.

scholarly journals Remote Sensing of Particle Cross-Sectional Area in the Bohai Sea and Yellow Sea: Algorithm Development and Application Implications

2016 ◽  
Vol 8 (10) ◽  
pp. 841 ◽  
Author(s):  
Shengqiang Wang ◽  
Yu Huan ◽  
Zhongfeng Qiu ◽  
Deyong Sun ◽  
Hailong Zhang ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Yellow Sea ◽  
Bohai Sea ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Algorithm Development ◽  
The Bohai Sea

scholarly journals Flood discharge measurement of a mountain river – Nanshih River in Taiwan

2013 ◽  
Vol 17 (5) ◽  
pp. 1951-1962 ◽  
Author(s):  
Y.-C. Chen
Keyword(s):  
Measurement System ◽  
Maximum Velocity ◽  
Cross Sectional Area ◽  
Mountain River ◽  
Sectional Area ◽  
Mean Velocity ◽  
Cross Sectional ◽  
Discharge Measurement ◽  
Flood Discharge ◽  
Water Stage

Abstract. This study proposes a more efficient method of flood discharge measurement in mountain rivers that accounts for personal safety, accuracy, and reliability. Because it is based on the relationships between mean and maximum velocities and between cross-sectional area and gauge height, the proposed method utilizes a flood discharge measurement system composed of an acoustic Doppler profiler and crane system to measure velocity distributions, cross-sectional area, and water depths. The flood discharge measurement system can be used to accurately and quickly measure flood data that is difficult to be collected by the conventional instruments. The measured data is then used to calibrate the parameters of the proposed method for estimating mean velocity and cross-sectional area. Then these observed discharge and gauge height can be used to establish the water stage–discharge rating curve. Therefor continuous and real-time estimations of flood discharge of a mountain river can become possible. The measurement method and system is applied to the Nanshih River at the Lansheng Bridge. Once the method is established, flood discharge of the Nanshih River could be efficiently estimated using maximum velocity and the water stage. Results of measured and estimated discharges of the Nanshih River at the Lansheng Bridge differed only slightly from each other, demonstrating the efficiency and accuracy of the proposed method.

scholarly journals Effects of long-term, high-altitude hypoxia on the capillarity of the ovine fetal heart

1999 ◽  
Vol 277 (2) ◽  
pp. H756-H762 ◽  
Author(s):  
A. M. Lewis ◽  
O. Mathieu-Costello ◽  
P. J. McMillan ◽  
R. D. Gilbert
Keyword(s):  
Right Ventricle ◽  
High Altitude ◽  
Capillary Density ◽  
Volume Density ◽  
Capillary Diameter ◽  
Sectional Area ◽  
Anisotropy Coefficient ◽  
Capillary Length ◽  
Cross Sectional ◽  
The Right

To determine the effect of chronic hypoxia on myocardial capillarity, we exposed pregnant ewes to an altitude of 3,820 m from day 30 to day 139 of gestation and compared the fetus to low-altitude (∼300 m) controls. We hypothesized that capillarity would increase in the hypoxic myocardium to optimize oxygen and metabolite flux to hypoxic tissues. Fetal hearts were fixed by retrograde aortic perfusion and processed for microscopy and stereological evaluation. Fiber cross-sectional area and capillary density were measured and standardized to sarcomere length. Capillary volume density and capillary diameter were measured, capillary-to-fiber ratio and capillary length density were calculated, and the capillary anisotropy coefficient was obtained from a table of known values. Capillary-to-fiber ratio, capillary volume density, and the capillary anisotropy coefficient were not different between hypoxia and control groups. Capillary diameter was significantly larger in the right compared with the left ventricle of hypoxic but not control hearts; fiber cross-sectional area tended to be larger in the right ventricle of both groups, but this was not significant. As a result of larger fiber size, capillary density and capillary length density were significantly smaller in the right ventricle of hypoxic but not control fetal hearts. Contrary to our hypothesis, the ovine fetus does not show morphological adaptation in the myocardium after ∼109 days of high-altitude hypoxic stress.

Greater uterine artery blood flow during pregnancy in multigenerational (Andean) than shorter-term (European) high-altitude residents

2007 ◽  
Vol 293 (3) ◽  
pp. R1313-R1324 ◽  
Author(s):  
Megan J. Wilson ◽  
Miriam Lopez ◽  
Marco Vargas ◽  
Colleen Julian ◽  
Wilma Tellez ◽  
...  
Keyword(s):  
Blood Flow ◽  
Birth Weight ◽  
High Altitude ◽  
Fetal Growth ◽  
Uterine Artery ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
La Paz ◽  
Near Term

Multigenerational (Andean) compared with shorter-term (European) high-altitude residents exhibit less hypoxia-associated reductions in birth weight. Because differences in arterial O2content are not responsible, we asked whether greater pregnancy-associated increases in uterine artery (UA) blood flow and O2delivery were involved. Serial studies were conducted in 42 Andean and 26 European residents of La Paz, Bolivia (3600 m) at weeks 20, 30, 36 of pregnancy and 4 mo postpartum using Doppler ultrasound. There were no differences postpartum but Andean vs. European women had greater UA diameter (0.65 ± 0.01 vs. 0.56 ± 0.01 cm), cross-sectional area (33.1 ± 0.97 vs. 24.7 ± 1.18 mm2), and blood flow at week 36 (743 ± 87 vs. 474 ± 36 ml/min) (all P < 0.05) and thus 1.6-fold greater uteroplacental O2delivery near term (126.82 ± 18.47 vs. 80.33 ± 8.69 ml O2·ml blood−1·min−1, P < 0.05). Andeans had greater common iliac (CI) flow and lower external iliac relative to CI flow (0.52 ± 0.11 vs. 0.95 ± 0.14, P < 0.05) than Europeans at week 36. After adjusting for gestational age, maternal height, and parity, Andean babies weighed 209 g more than the Europeans. Greater UA cross-sectional area at week 30 related positively to birth weight in Andeans ( r = +0.39) but negatively in Europeans ( r = −0.37) (both P < 0.01). We concluded that a greater pregnancy-associated increase in UA diameter raised UA blood flow and uteroplacental O2delivery in the Andeans and contributed to their ability to maintain normal fetal growth under conditions of high-altitude hypoxia. These data implicate the involvement of genetic factors in protecting multigenerational populations from hypoxia-associated reductions in fetal growth, but future studies are required for confirmation and identification of the specific genes involved.

scholarly journals Physiological profile of world-class high-altitude climbers

1986 ◽  
Vol 60 (5) ◽  
pp. 1734-1742 ◽  
Author(s):  
O. Oelz ◽  
H. Howald ◽  
P. E. Di Prampero ◽  
H. Hoppeler ◽  
H. Claassen ◽  
...  
Keyword(s):  
High Altitude ◽  
Muscle Fiber ◽  
Anaerobic Power ◽  
Cross Sectional Area ◽  
Type I ◽  
Sectional Area ◽  
Long Distance ◽  
Cross Sectional ◽  
Normal Limits ◽  
World Class

The functional characteristics of six world-class high-altitude mountaineers were assessed 2–12 mo after the last high-altitude climb. Each climber on one or several occasions had reached altitudes of 8,500 m or above without supplementary O2. Static and dynamic lung volumes and right and left echocardiographic measurements were found to be within normal limits of sedentary controls (SC). Muscle fiber distribution was 70% type I, 22% type IIa, and 7% type IIb. Mean muscle fiber cross-sectional area was significantly smaller than that of SC (-15%) and of long-distance runners (LDR, -51%). The number of capillaries per unit cross-sectional area was significantly greater than that of SC (+ 40%). Total mitochondrial volume was not significantly different from that of SC, but its subsarcolemmal component was equal to that of LDR. Average maximal O2 consumption was 60 +/- 6 ml X kg-1 X min-1, which is between the values of SC and LDR. Average maximal anaerobic power was 28 +/- 2.5 W X kg-1, which is equal to that of SC and 40% lower that that of competitive high jumpers. All subjects were characterized by resting hyperventilation both in normoxia and in moderate (inspired O2 partial pressure = 77 Torr) hypoxia resulting in higher oxyhemoglobin saturation levels in hypoxia. The ventilatory response to four tidal volumes of pure O2 was similar to that of SC. It is concluded that elite high-altitude climbers do not have physiological adaptations to high altitude that justify their unique performance.

scholarly journals Surface Flow Velocities From Space: Particle Image Velocimetry of Satellite Video of a Large, Sediment-Laden River

2021 ◽  
Vol 3 ◽  
Author(s):  
Carl J. Legleiter ◽  
Paul J. Kinzel
Keyword(s):  
Remote Sensing ◽  
Particle Image Velocimetry ◽  
River Discharge ◽  
Water Surface ◽  
Particle Image ◽  
Field Measurements ◽  
Surface Flow ◽  
Cross Sectional ◽  
Image Velocimetry ◽  
Flow Velocities

Conventional, field-based streamflow monitoring in remote, inaccessible locations such as Alaska poses logistical challenges. Safety concerns, financial considerations, and a desire to expand water-observing networks make remote sensing an appealing alternative means of collecting hydrologic data. In an ongoing effort to develop non-contact methods for measuring river discharge, we evaluated the potential to estimate surface flow velocities from satellite video of a large, sediment-laden river in Alaska via particle image velocimetry (PIV). In this setting, naturally occurring sediment boil vortices produced distinct water surface features that could be tracked from frame to frame as they were advected by the flow, obviating the need to introduce artificial tracer particles. In this study, we refined an end-to-end workflow that involved stabilization and geo-referencing, image preprocessing, PIV analysis with an ensemble correlation algorithm, and post-processing of PIV output to filter outliers and scale and geo-reference velocity vectors. Applying these procedures to image sequences extracted from satellite video allowed us to produce high resolution surface velocity fields; field measurements of depth-averaged flow velocity were used to assess accuracy. Our results confirmed the importance of preprocessing images to enhance contrast and indicated that lower frame rates (e.g., 0.25 Hz) lead to more reliable velocity estimates because longer capture intervals allow more time for water surface features to translate several pixels between frames, given the relatively coarse spatial resolution of the satellite data. Although agreement between PIV-derived velocity estimates and field measurements was weak (R2 = 0.39) on a point-by-point basis, correspondence improved when the PIV output was aggregated to the cross-sectional scale. For example, the correspondence between cross-sectional maximum velocities inferred via remote sensing and measured in the field was much stronger (R2 = 0.76), suggesting that satellite video could play a role in measuring river discharge. Examining correlation matrices produced as an intermediate output of the PIV algorithm yielded insight on the interactions between image frame rate and sensor spatial resolution, which must be considered in tandem. Although further research and technological development are needed, measuring surface flow velocities from satellite video could become a viable tool for streamflow monitoring in certain fluvial environments.

scholarly journals Shape dependence of snow crystal fall speed

2020 ◽  
Author(s):  
Sandra Vázquez-Martín ◽  
Thomas Kuhn ◽  
Salomon Eliasson
Keyword(s):  
Remote Sensing ◽  
Numerical Models ◽  
Area Ratio ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Ice Particles ◽  
Fall Speed ◽  
Remote Sensing Techniques

Abstract. Improved snowfall predictions require accurate knowledge of the properties of ice crystals and snow particles, such as their size, cross-sectional area, shape, and fall speed. In particular, the shape is an important parameter as it strongly influences the scattering properties of these ice particles, and thus their response to remote sensing techniques such as radar measurements. The fall speed of ice particles is a critical parameter for the representation of ice clouds and snow in atmospheric numerical models, as it determines the rate of removal of ice from the modelled clouds. They are also required for snowfall predictions alongside other properties such as ice particle size, cross-sectional area, and shape. For example, shape is important as it strongly influences the scattering properties of these ice particles, and thus their response to remote sensing techniques. This work analyses fall speed as a function of shape and other properties using ground-based in-situ measurements. The measurements for this study were done in Kiruna, Sweden during the snowfall seasons of 2014 to 2019, using the ground-based in-situ instrument Dual Ice Crystal Imager (D-ICI). The resulting data consist of high-resolution images of falling hydrometeors from two viewing geometries that are used to determine size (maximum dimension), cross-sectional area, area ratio, orientation, and the fall speed of individual particles. The selected dataset covers sizes from about 0.06 to 3.2 mm and fall speeds from 0.06 to 1.6 m s−1. The particles are shape-classified into 15 different shape groups depending on their shape and morphology. For these 15 shape groups relationships are studied, firstly, between size and cross-sectional area, then between fall speed and size or cross-sectional area. The data show in general low correlations to fitted fall-speed relationships due to large spread observed in fall speed. After binning the data according to size or cross-sectional area, correlations improve and we can report reliable parameterizations of fall speed vs. size or cross-sectional area for part of the shapes. The effects of orientation and area ratio on the fall speed are also studied, and measurements show that vertically orientated particles fall faster on average. However, most particles for which orientation can be defined fall horizontally.

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