scholarly journals A Wind–Wave-Dependent Sea Spray Volume Flux Model Based on Field Experiments

2021 ◽  
Vol 9 (11) ◽  
pp. 1168
Author(s):  
Xingkun Xu ◽  
Joey J. Voermans ◽  
Hongyu Ma ◽  
Changlong Guan ◽  
Alexander V. Babanin
Keyword(s):  
Field Experiments ◽  
Wind Wave ◽  
Weather Forecasting ◽  
Sea Spray ◽  
Volume Flux ◽  
Laser Altimeter ◽  
Flux Model ◽  
Spray Volume ◽  
Wave Properties

Sea spray can contribute significantly to the exchanges of heat and momentum across the air–sea interface. However, while critical, sea spray physics are typically not included in operational atmospheric and oceanic models due to large uncertainties in their parameterizations. In large part, this is because of the scarcity of in-situ sea spray observations which prevent rigorous validation of existing sea spray models. Moreover, while sea spray is critically produced through the fundamental interactions between wind and waves, traditionally, sea spray models are parameterized in terms of wind properties only. In this study, we present novel in-situ observations of sea spray derived from a laser altimeter through the adoption of the Beer–Lambert law. Observations of sea spray cover a broad range of wind and wave properties and are used to develop a wind–wave-dependent sea spray volume flux model. Improved performance of the model is observed when wave properties are included, in contrast to a parameterization based on wind properties alone. The novel in-situ sea spray observations and the predictive model derived here are consistent with the classic spray model in both trend and magnitude. Our model and novel observations provide opportunities to improve the prediction of air–sea fluxes in operational weather forecasting models.

The estimation of sea spray at wind speeds ranging from light to extreme

2021 ◽  
Author(s):  
Xingkun Xu ◽  
Joey Voermans ◽  
Alexander Babanin ◽  
Hongyu Ma ◽  
Changlong Guan
Keyword(s):  
Laser Beam ◽  
Beam Intensity ◽  
Sea Spray ◽  
Wave Steepness ◽  
Volume Flux ◽  
Laser Beam Intensity ◽  
Infrared Laser Beam ◽  
Flux Model ◽  
The Mean ◽  
Spray Volume

<p>As one of typical elements in the air-sea boundary layer, sea spray is expected to mediate energy flux exchange in the air and ocean boundary layers, and therefore it is of crucial importance to the meteorology, oceanology, and regional climatology. In addition, the spray is also considered as one of the missing physical mechanisms in atmospheric and oceanic numerical models. Hence, it is necessary to accurately predict how much sea spray is produced at the air-sea boundary layer. Though spray has been studied for a number of decades, large uncertainties still linger. For instance, uncertainties in qualifying how much spray is produced on the sea surface reach 10<sup>6</sup> times. This is because of the rarity of spray observations in the field, especially under strong wind condition.</p><p>To give a reliable spray production model, scientists tried to employ laser-based facilities in the field to observe sea spray by interpreting infrared laser-beam intensity into sea spray volume flux over the water surface. Hence, in the current study, we collected datasets in the field measured by laser-based facilities on the North-West Shelf of the coast of Western Australia, thereafter, further analyzed, and calibrated them through a series of academic, statistical, and physical analysis to ensure the data quality. After that, assuming the existence of spray drops in the air-sea layer would attenuate the infrared laser-beam intensity, the weakening extends of laser-beam intensity is used to estimate the volume flux of sea spray above the ocean surface at winds speed ranging from light to extreme during the passage of Tropical Cyclone Olwyn (2015). It should be noted that our observations of sea spray volume flux are within the ranges of existing models and are consistent with the model proposed by Andreas (1992) in both trend and magnitude.</p><p>Using the field observations of the sea spray volume flux, a sea spray volume flux model can be constructed. Given that sea spray droplets are generated at the ocean surface through breaking waves and wind shear, the sea spray volume flux is expected to be dominated by the properties of the local wind and wave field. For physical consistency across the wide range of scales observed in the field and laboratory, non-dimensional parameters (i.e., non-dimensional wind speed and the mean wave steepness) were adopted to construct the model. Consequently, a power-law non-dimensional spray volumetric flux model is suggested based on the estimation of the spray volume flux. It should be noted that one sensitive test was conducted to substantiate the inclusion of wave breaking process, here simply included with the mean wave steepness, improves spray volume flux parameterization.</p>

Estimating sea spray volume with a laser altimeter

2011 ◽  
pp. 110421064116041
Author(s):  
A. Toffoli ◽  
A. V. Babanin ◽  
M. A. Donelan ◽  
B. K. Haus ◽  
D. Jeong
Keyword(s):  
Sea Spray ◽  
Laser Altimeter ◽  
Spray Volume

Estimating Sea Spray Volume with a Laser Altimeter

2011 ◽  
Vol 28 (9) ◽  
pp. 1177-1183 ◽  
Author(s):  
A. Toffoli ◽  
A. V. Babanin ◽  
M. A. Donelan ◽  
B. K. Haus ◽  
D. Jeong
Keyword(s):  
Laser Radiation ◽  
Water Surface ◽  
Sea Spray ◽  
Average Intensity ◽  
Laser Altimeter ◽  
Indirect Measure ◽  
Simple Regression Model ◽  
Spray Droplets ◽  
Laser Altimeters ◽  
Spray Volume

Abstract Down-looking laser altimeters are commonly used to measure the sea surface elevation. However, because the laser radiation is attenuated by spray droplets suspended along the transmission path, it is presumed that altimeters may also provide an indirect measure of the sea spray volume. Here, this conjecture is discussed by means of laboratory experiments, which have been conducted in a wind-wave flume. A large number of wind conditions were considered between equivalent 10-m wind speeds of 20 and 60 m s−1 in order to generate different spray volumes above the water surface. The facility was equipped with a laser and side-looking camera system to estimate the spray volume as well as a nearby down-looking laser altimeter. Results confirm that there is a robust degradation of the laser intensity for increasing wind speed and hence the amount of spray droplets above the water surface. A simple regression model to extract spray volume from the average intensity of the laser radiation is presented, demonstrating the promise of laser altimeters for making in situ spray observations. Additional observations will be required to calibrate the altimeters for applications in the open ocean marine environment.

scholarly journals A UAV-RTK-LIDAR SYSTEM MEASUREMENTS OF WAVE ENERGY DISSIPATION OVER A SANDY BEACH AND AN ALGAL-REEF AREA

2020 ◽  
pp. 34
Author(s):  
Cheng-yang Yeh ◽  
Zhi-Cheng Huang
Keyword(s):  
Energy Dissipation ◽  
Wave Energy ◽  
Field Experiments ◽  
Sandy Beach ◽  
Lidar System ◽  
Wave Energy Dissipation ◽  
Algal Reef ◽  
Wave Properties ◽  
Beach Site

Wave energy dissipation is a significant factor affecting coastal hydrodynamics, coastline morphology, wave height transformation, and the nutrient uptake in the coral reef (Huang, Lenain et al. 2012). However, it is difficult to be measured since accurate and spatial-distributed measurements of sea surface elevations are required to compute this quantity. We used a UAV-RTK-Lidar system to test the possibility for the measurements of wave energy dissipation. The UAV system was validated to able to measure the ocean wave properties (Huang, Yeh et al. 2018). Two field experiments of measuring energy dissipation were conducted over an algal-reef and a sandy beach site, respectively. Nine and eight flights of UAV measurements on the algal reef and sandy beach were conducted for one tidal cycle. The measurements of wave properties by UAV were compared with those of in-situ instruments using pressure sensors.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/fBLbsBuK4AA

Filed observations of spray production function during Tropical Cyclones Olwyn and Veronica

2020 ◽  
Author(s):  
Alexander Babanin ◽  
Hongyu Ma ◽  
Xingkun Xu ◽  
Fangli Qiao
Keyword(s):  
Tropical Cyclones ◽  
Heat Fluxes ◽  
Sea Spray ◽  
Laser Array ◽  
Cyclone Intensity ◽  
Wind Speeds ◽  
The Indian Ocean ◽  
The Waves ◽  
Wave Properties

<p>Spray produced in Tropical Cyclones affects the dynamic and heat fluxes between the atmosphere and ocean, and thus can influence the Cyclone intensity in a number of ways. Measurements of the Sea Spray Generation Function (SSGF) in situ, however, are extremely challenging and correspondingly rare, and uncertainties in quantifying SSGF reach 1000 times.</p><p>In the presentation, measurements of the total volume of spray by means of a laser array in Tropical Cyclones Olwyn (2015) and Veronica (2019) in the Indian Ocean will be reported. They are used to develop a parameterisation of SSGF at wind speeds ranging from light to extreme. It is argued that the spray is produced by wind-over-the-waves, and therefore wave properties are also accounted for in the parameterisation.</p>

STORM ICE OIL WIND WAVE WATCH SYSTEM (SIOWS): WEB GIS APPLICATION FOR MONITORING THE ARCTIC

2017 ◽  
Author(s):  
Alexander Myasoedov ◽  
Alexander Myasoedov ◽  
Sergey Azarov ◽  
Sergey Azarov ◽  
Ekaterina Balashova ◽  
...  
Keyword(s):  
Satellite Data ◽  
Wind Wave ◽  
Arctic Region ◽  
Web Gis ◽  
The Arctic ◽  
Flexible Tool ◽  
In Situ Data ◽  
Current State ◽  
Watch System

Working with satellite data, has long been an issue for users which has often prevented from a wider use of these data because of Volume, Access, Format and Data Combination. The purpose of the Storm Ice Oil Wind Wave Watch System (SIOWS) developed at Satellite Oceanography Laboratory (SOLab) is to solve the main issues encountered with satellite data and to provide users with a fast and flexible tool to select and extract data within massive archives that match exactly its needs or interest improving the efficiency of the monitoring system of geophysical conditions in the Arctic. SIOWS - is a Web GIS, designed to display various satellite, model and in situ data, it uses developed at SOLab storing, processing and visualization technologies for operational and archived data. It allows synergistic analysis of both historical data and monitoring of the current state and dynamics of the "ocean-atmosphere-cryosphere" system in the Arctic region, as well as Arctic system forecasting based on thermodynamic models with satellite data assimilation.

scholarly journals Microbial Functional Gene Diversity with a Shift of Subsurface Redox Conditions duringIn SituUranium Reduction

2012 ◽  
Vol 78 (8) ◽  
pp. 2966-2972 ◽  
Author(s):  
Yuting Liang ◽  
Joy D. Van Nostrand ◽  
Lucie A. N′Guessan ◽  
Aaron D. Peacock ◽  
Ye Deng ◽  
...  
Keyword(s):  
Functional Diversity ◽  
Field Experiments ◽  
Gene Diversity ◽  
Functional Gene ◽  
Redox Conditions ◽  
Functional Genes ◽  
Microbial Functional Diversity ◽  
Content Type ◽  
Microbial Functional Gene

ABSTRACTTo better understand the microbial functional diversity changes with subsurface redox conditions duringin situuranium bioremediation, key functional genes were studied with GeoChip, a comprehensive functional gene microarray, in field experiments at a uranium mill tailings remedial action (UMTRA) site (Rifle, CO). The results indicated that functional microbial communities altered with a shift in the dominant metabolic process, as documented by hierarchical cluster and ordination analyses of all detected functional genes. The abundance ofdsrABgenes (dissimilatory sulfite reductase genes) and methane generation-relatedmcrgenes (methyl coenzyme M reductase coding genes) increased when redox conditions shifted from Fe-reducing to sulfate-reducing conditions. The cytochrome genes detected were primarily fromGeobactersp. and decreased with lower subsurface redox conditions. Statistical analysis of environmental parameters and functional genes indicated that acetate, U(VI), and redox potential (Eh) were the most significant geochemical variables linked to microbial functional gene structures, and changes in microbial functional diversity were strongly related to the dominant terminal electron-accepting process following acetate addition. The study indicates that the microbial functional genes clearly reflect thein situredox conditions and the dominant microbial processes, which in turn influence uranium bioreduction. Microbial functional genes thus could be very useful for tracking microbial community structure and dynamics during bioremediation.

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