scholarly journals A New Quasi-Horizontal Glider to Measure Biophysical Microstructure

2014 ◽  
Vol 31 (10) ◽  
pp. 2278-2293 ◽  
Author(s):  
Herminio Foloni-Neto ◽  
Rolf Lueck ◽  
Yoshiro Mabuchi ◽  
Hisato Nakamura ◽  
Masakazu Arima ◽  
...  
Keyword(s):  
High Resolution ◽  
Internal Waves ◽  
Chlorophyll A Fluorescence ◽  
Field Experiments ◽  
Density Field ◽  
Velocity Shear ◽  
Length Scale ◽  
Flight Performance ◽  
Fluorescence Sensors ◽  
Horizontal Inhomogeneity

Abstract This study describes the development of a new tethered quasi-horizontal microstructure profiler: the Turbulence Ocean Microstructure Acquisition Profiler–Glider [TurboMAP-Glider (TMG)]. It is a unique instrument, capable of measuring ocean microstructure (temperature and turbulent velocity shear), chlorophyll, and turbidity simultaneously through a quasi-horizontal perspective. Three field experiments were carried out near Joga-shima, Japan, to test the TMG flight performance, and those results as well as comparisons with a laser-based vertical profiler, TurboMAP-L (TM), are described here. The TMG was capable of flying with an angle of attack of less than 25° and was reasonably stable for up to 300 m horizontally over 100-m depth. Some new and relevant empirical results about quasi-horizontal application of high-resolution chlorophyll-a fluorescence sensors are presented. The ratio between the Thorpe length scale and the Ozmidov length scale was used as a tracer to demonstrate that most of the TMG density inversions are due to horizontal variability and not to vertical overturning. These waveform structures are probably due to the horizontal inhomogeneity of the density field and are likely caused by internal waves.

scholarly journals Representation of Vertical Atmospheric Structures by Radio Occultation Observations in the Upper Troposphere and Lower Stratosphere: Comparison to High-Resolution Radiosonde Profiles

2019 ◽  
Vol 36 (4) ◽  
pp. 655-670 ◽  
Author(s):  
Zhen Zeng ◽  
Sergey Sokolovskiy ◽  
William S. Schreiner ◽  
Doug Hunt
Keyword(s):  
High Resolution ◽  
Radio Occultation ◽  
Lower Stratosphere ◽  
Small Scale ◽  
Tropical Tropopause Layer ◽  
Tropical Tropopause ◽  
Low Latitudes ◽  
Observational Noise ◽  
Horizontal Inhomogeneity ◽  
Cold Point

AbstractGlobal positioning system (GPS) radio occultation (RO) is capable of retrieving vertical profiles of atmospheric parameters with high resolution (<100 m), which can be achieved in spherically symmetric atmosphere. Horizontal inhomogeneity of real atmosphere results in representativeness errors of retrieved profiles. In most cases these errors increase with a decrease of vertical scales of atmospheric structures and may not allow one to fully utilize the physical resolution of RO. Also, GPS RO–retrieved profiles are affected by observational noise of different types, which, in turn, affect the representation of small-scale atmospheric structures. This study investigates the effective resolution and optimal smoothing of GPS RO–retrieved temperature profiles using high-pass filtering and cross correlation with collocated high-resolution radiosondes. The effective resolution is a trade-off between representation of real atmospheric structures and suppression of observational noise, which varies for different latitudes (15°S–75°N) and altitudes (10–27 km). Our results indicate that at low latitudes the effective vertical resolution is about 0.2 km near the tropical tropopause layer and about 0.5 km in the lower stratosphere. The best resolution of 0.1 km is at the cold-point tropical tropopause. The effective resolutions at the midlatitudes are slightly worse than at low latitudes, varying from ~0.2 to 0.6 km. At high latitudes, the effective resolutions change notably with altitude from ~0.2 km at 10–15 km to ~1.4 km at 22–27 km. Our results suggest that the atmospheric inhomogeneity plays an important role in the representation of the vertical atmospheric structures by RO measurements.

Seasonal dynamics of internal waves governed by stratification stability and wind: Analysis of high‐resolution observations from the Dead Sea

2019 ◽  
Vol 64 (5) ◽  
pp. 1864-1882 ◽  
Author(s):  
Ali Arnon ◽  
Steve Brenner ◽  
John S. Selker ◽  
Isaac Gertman ◽  
Nadav G. Lensky
Keyword(s):  
High Resolution ◽  
Internal Waves ◽  
Seasonal Dynamics ◽  
Dead Sea ◽  
Wind Analysis ◽  
The Dead

A Model of Liquid-Drop Spreading for Electrohydrodynamic Jet Printing

2015 ◽  
Author(s):  
Christopher P. Pannier ◽  
Kira Barton ◽  
David Hoelzle ◽  
Zhi Wang
Keyword(s):  
High Resolution ◽  
Viscous Friction ◽  
Length Scale ◽  
Droplet Spreading ◽  
Loop Control ◽  
Electrohydrodynamic Jet Printing ◽  
Viscous Losses ◽  
Jet Printing ◽  
Base Radius ◽  
Small Disturbances

Electrohydrodynamic jet (E-jet) printing is a recent technique for high resolution additive micromanufacturing. With high resolution comes sensitivity to small disturbances, which has kept this technique from reaching its industrial potential. Closed loop control of E-jet printing can overcome these disturbances, but it requires an improved understanding of ink droplet spreading on the substrate and a physical model to predict printed feature locations and geometries from process inputs and disturbances. This manuscript examines a model of ink droplet spreading that uses assumptions that are important to the e-jet process. Our model leverages previous energy balance models that were derived for larger length scale droplets. At the smaller length scale, we find that viscous losses are a significant portion of the energy budget and must be accounted for; this is in contrast to models at length scales two orders of magnitude larger. Our model predicts the droplet height, base radius and contact angle in time from an initial volume and E-jet printing control parameters. The model is validated with published droplet spreading data and new measurements of E-jet printed droplets of diameter 8 μm. The viscous friction calculated in the new model is found to be significant compared to surface energy.

scholarly journals Foraging in an unsteady world: bumblebee flight performance in field-realistic turbulence

2017 ◽  
Vol 7 (1) ◽  
pp. 20160086 ◽  
Author(s):  
J. D. Crall ◽  
J. J. Chang ◽  
R. L. Oppenheimer ◽  
S. A. Combes
Keyword(s):  
Field Experiments ◽  
Insect Flight ◽  
Energetic Cost ◽  
Natural Environments ◽  
Flight Performance ◽  
Wingbeat Frequency ◽  
Wind Speeds ◽  
Wide Range ◽  
Outdoor Environments ◽  
Stroke Amplitude

Natural environments are characterized by variable wind that can pose significant challenges for flying animals and robots. However, our understanding of the flow conditions that animals experience outdoors and how these impact flight performance remains limited. Here, we combine laboratory and field experiments to characterize wind conditions encountered by foraging bumblebees in outdoor environments and test the effects of these conditions on flight. We used radio-frequency tags to track foraging activity of uniquely identified bumblebee ( Bombus impatiens ) workers, while simultaneously recording local wind flows. Despite being subjected to a wide range of speeds and turbulence intensities, we find that bees do not avoid foraging in windy conditions. We then examined the impacts of turbulence on bumblebee flight in a wind tunnel. Rolling instabilities increased in turbulence, but only at higher wind speeds. Bees displayed higher mean wingbeat frequency and stroke amplitude in these conditions, as well as increased asymmetry in stroke amplitude—suggesting that bees employ an array of active responses to enable flight in turbulence, which may increase the energetic cost of flight. Our results provide the first direct evidence that moderate, environmentally relevant turbulence affects insect flight performance, and suggest that flying insects use diverse mechanisms to cope with these instabilities.

scholarly journals A technical description of the Balloon Lidar Experiment (BOLIDE)

2020 ◽  
Vol 13 (10) ◽  
pp. 5681-5695
Author(s):  
Bernd Kaifler ◽  
Dimitry Rempel ◽  
Philipp Roßi ◽  
Christian Büdenbender ◽  
Natalie Kaifler ◽  
...  
Keyword(s):  
High Resolution ◽  
Time Resolution ◽  
Background Noise ◽  
Flight Performance ◽  
Vertical Resolution ◽  
Backscatter Coefficient ◽  
High Background ◽  
Polar Mesospheric Clouds ◽  
High Background Noise ◽  
Mesospheric Clouds

Abstract. The Balloon Lidar Experiment (BOLIDE) was the first high-power lidar flown and operated successfully on board a balloon platform. As part of the PMC Turbo payload, the instrument acquired high-resolution backscatter profiles of polar mesospheric clouds (PMCs) from an altitude of ∼ 38 km during its maiden ∼ 6 d flight from Esrange, Sweden, to northern Canada in July 2018. We describe the BOLIDE instrument and its development and report on the predicted and actual in-flight performance. Although the instrument suffered from excessively high background noise, we were able to detect PMCs with a volume backscatter coefficient as low as 0.6×10-10 m−1 sr−1 at a vertical resolution of 100 m and a time resolution of 30 s.

Variation in Length, Fecundity and Survival of Pink Wax Scale, Ceroplastes rubens Maskell (Hemiptera: Coccidae), on Umbrella Trees

1997 ◽  
Vol 45 (4) ◽  
pp. 399 ◽  
Author(s):  
A. D. Loch ◽  
M. P. Zalucki
Keyword(s):  
Field Experiments ◽  
Density Field ◽  
Test Length ◽  
Death Rates ◽  
First Instar ◽  
Over Time

We investigated some of the factors that may lead to outbreaks of pink wax scale, Ceroplastes rubens Maskell, on umbrella trees, Schefflera actinophylla (Endl.). Estimates of birth and death rates of pink wax scale were high and variable within and among trees; variation in these rates was not related to scale density. Adult fecundity correlated significantly but weakly with adult test length; mean fecundity was 292 eggs per female with a range of 5–1178. Adult test length and its variance decreased weakly with increasing density. Field experiments showed that mortality of C. rubens is greatest during the first 24 hours after hatching when approximately half disappear. The rate of loss decreases over time with 0·3% of initial motile first- instar nymphs surviving to maturity. Rates of loss varied significantly between trees, indicating that some trees are more suitable for scale colonisation and survival.

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