scholarly journals A GROSS LONGSHORE TRANSPORT RATE FORMULA

1972 ◽  
Vol 1 (13) ◽  
pp. 47 ◽  
Author(s):  
Cyril J. Galvin
Keyword(s):  
Current Velocity ◽  
Empirical Relation ◽  
Field Measurements ◽  
Transport Rate ◽  
Longshore Current ◽  
Physical Explanation ◽  
Littoral Drift ◽  
Longshore Transport ◽  
Term Field

Gross longshore transport rates for 11 long-term field measurements are predicted reasonably well by the empirical relation, Q=2H2, where Q is longshore transport rate in 100,000 yd3/yr, and H is a mean breaker height in feet. A physical explanation of this empirical relation assumes: (1) most littoral drift is transported in suspension; (2) longshore current velocity is predicted by V-gmTsin28j,; (3) the empirical relation is an equation for conservation of suspended sediment in the longshore current.

scholarly journals LONGSHORE TRANSPORT OF SAND

1968 ◽  
Vol 1 (11) ◽  
pp. 18 ◽  
Author(s):  
Douglas L. Inman ◽  
Paul D. Komar ◽  
Anthony J. Bowen
Keyword(s):  
Energy Flux ◽  
Surf Zone ◽  
Field Measurements ◽  
Breaking Waves ◽  
Transport Rate ◽  
Wave Power ◽  
Longshore Transport ◽  
Wave Conditions

Simultaneous field measurements of the energy flux of breaking waves and the resulting longshore transport of sand in the surf zone have been made along three beaches and for a variety of wave conditions. The measurements indicate that the longshore transport rate of sand is directly proportional to the longshore component of wave power.

scholarly journals Comment on ''Observing desert dust devils with a pressure logger" by Lorenz (2012) – insights on measured pressure fluctuations from large-eddy simulations

2012 ◽  
Vol 1 (2) ◽  
pp. 151-154 ◽  
Author(s):  
A. Spiga
Keyword(s):  
Pressure Fluctuations ◽  
Field Measurements ◽  
Large Eddy Simulations ◽  
Pressure Measurements ◽  
Dust Devils ◽  
Pressure Drops ◽  
Large Eddy ◽  
Measured Pressure ◽  
Term Field

Abstract. Lorenz et al. (2012) proposes to use pressure loggers for long-term field measurements in terrestrial deserts. The dataset obtained through this method features both pressure drops (reminiscent of dust devils) and periodic convective signatures. Here we use large-eddy simulations to provide an explanation for those periodic convective signatures and to argue that pressure measurements in deserts have broader applications than monitoring dust devils.

A long-term field study (1951-2003) of ventifacts formed by katabatic winds at Paulatuk, western Arctic coast, Canada

2005 ◽  
Vol 42 (9) ◽  
pp. 1615-1635 ◽  
Author(s):  
J Ross Mackay ◽  
C R Burn
Keyword(s):  
Field Measurements ◽  
Katabatic Winds ◽  
Abrasion Rate ◽  
Western Arctic ◽  
Arctic Coast ◽  
Optical Examination ◽  
East West ◽  
Coastal Settlement ◽  
Term Field

Field measurements have been made since 1951 on hundreds of ventifacts abraded by strong, southerly, katabatic winds that blow in winter and summer past Paulatuk, a small western Arctic coastal settlement. Sand is commonly entrained by the strongest winds in winter. The ventifacts, all glacial erratics deposited prior to 12 ka BP, have been gradually rotated by the southerly winds until the long axes of most ventifacts now trend approximately east–west, normal to the katabatic winds. In contrast, pebbles have a slightly preferred north–south orientation, parallel to the katabatic winds. The facets on sandstone and diabase ventifacts are almost planar, but are rounded on granites and hackled on limestones, reflecting the influence of both solution and abrasion. Abrasion is evident on the built structures in Paulatuk, but despite the over 50 years of observation, abrasion of the ventifacts has been virtually undetectable. The extremely slow abrasion rate has been estimated from: observations on two ventifacts from 1951 to 2003; photographic comparisons and observations of 60 ventifacts from 1968 to 2003; optical examination of 14 granite slabs, polished and unpolished, exposed to abrasion from 1967 to 1976; and comparisons of the windward and leeward sides of six large rock caches built with ventifacts probably long before 1900. If the present rates of abrasion are representative of Holocene conditions, ventifact formation has probably taken much of postglacial time. The increase in vegetation cover around many rocks between 1968 and 2003 suggests that the climate has changed in the last three decades.

scholarly journals Temperature influence on the natural aerosol budget over boreal forests

2013 ◽  
Vol 13 (12) ◽  
pp. 33311-33342
Author(s):  
L. Liao ◽  
V.-M. Kerminen ◽  
M. Boy ◽  
M. Kulmala ◽  
M. Dal Maso
Keyword(s):  
Boreal Forests ◽  
Particle Number ◽  
Field Measurements ◽  
Back Trajectories ◽  
Aerosol Mass ◽  
Higher Temperature ◽  
A Minor ◽  
Natural Aerosol ◽  
Term Field

Abstract. We investigated the natural aerosol evolution from biogenic monoterpene emissions among northern boreal forest area as function of temperature, using long-term field measurements of aerosol size distributions and back trajectories at two stations SMEAR I and SMEAR II in Finland. Particles were formed via nucleation through the clean ocean to land transition of air parcels, and continuously grew to larger sizes during air mass transport. Both the travelling hour over land and temperature influences the evolution of the particle number size distribution and the average aerosol mass yield from BVOC emissions. Average concentrations of nucleation mode particles were higher at lower temperatures, whereas the opposite was true for accumulation mode particles, thus more CCN may be formed at higher temperature. The overall apparent aerosol yield derived from the aerosol masses against accumulated monoterpene emissions ranges 13–37% with a minor yet complicating temperature dependence.

scholarly journals Analisa Model Matematik Arus Sejajar Pantai Pada Groin Seri Permeable

2018 ◽  
Vol 19 (2) ◽  
pp. 113
Author(s):  
Adi Surya Pria Pranata ◽  
Novi Andhi Setyo Purwono ◽  
Ary Sismiani
Keyword(s):  
Current Velocity ◽  
Physical Modeling ◽  
Surf Zone ◽  
Rip Current ◽  
Longshore Current ◽  
Long Distance ◽  
Direction Of Movement ◽  
The Mathematical Model ◽  
Additional Reduction

This research is the mathematical model has been made with two groins, permeable and impermeable groins, with the variation is in length and distance; 50 meters, 100 meters, 150 meters and 200 meters. A modelling has been done by using the data of physical modeling study by Chen., et al, 2003, and used as input to the simulation of mathematical models using 2D Boussinesq software.Results of the research showed the influence of variation model long distance between the groins, the reduction of longshore current velocity along the coast with an average 59.21% reduction for the double permeable groin with 50 meters long, 76.02% for 100 meters, 79.50% for 150 meters, 80.49% for 200 meters. The reduction of longshore current velocity along the coast are 57.42% for an impermeable groin groin double with 50 meters, 84.61% for 100 meters, 150% for 88.89 meters, and 89.91% for 200 meters. The distance variation between one groin to the other groin has a result that a longer permeable or impermeable groin affects the reduction longshore current velocity along the coast of the Surf Zone with the addition of longshore current velocity reduction occurs along the coast up to 20%. Reduction of longshore current velocity along the coast by the permeable and impermeable groin Permeable and impermeable groins has not been significantly occured in the long-term groin area exceeding Surf zone with an average additional reduction up to 5%. The longshore current velocity approaching the speed of currents along the coast for the existing conditions at a distance up to 2.4 times of length of groins. And the distance between the groins are too close if we compare to the long groins causing the current direction of movement towards the sea (rip Current). 

scholarly journals Comment on "Observing desert dust devils with a pressure logger" by Lorenz (2012)

2012 ◽  
Vol 2 (2) ◽  
pp. 593-601 ◽  
Author(s):  
A. Spiga
Keyword(s):  
Field Measurements ◽  
Large Eddy Simulations ◽  
Pressure Measurements ◽  
Dust Devils ◽  
Pressure Drops ◽  
Desert Dust ◽  
Large Eddy ◽  
Term Field

Abstract. Lorenz (2012) proposes to use pressure loggers for long-term field measurements in terrestrial deserts. The dataset obtained through this method features both pressure drops (reminiscent of dust devils) and periodic convective signatures. Here we use Large-Eddy Simulations to provide an explanation for those periodic convective signatures and to argue that pressure measurements in deserts have broader applications than monitoring dust devils.

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