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Error Analysis and Improved Design of Target Board Reflection for Visibility Measurement by the Image Methodsurveillance have been studied over the past several years. Steffens (1949) proposed an idea of measuring visibility by using the visual characteristics of images, which is first measures the physical characteristics of the atmosphere and then indirectly transforms them into visibility. Bellver (1987) used a 1-yr measurement test to determine the meteorological range, which was performed by photographing black targets and the sky by an automatic recording microdensitometer. Kimura et al. (2007
surveillance have been studied over the past several years. Steffens (1949) proposed an idea of measuring visibility by using the visual characteristics of images, which is first measures the physical characteristics of the atmosphere and then indirectly transforms them into visibility. Bellver (1987) used a 1-yr measurement test to determine the meteorological range, which was performed by photographing black targets and the sky by an automatic recording microdensitometer. Kimura et al. (2007
their generation and dissipation sites and for estimating their intensity, energy, and energy flux. Shipboard and moored acoustic Doppler current profiler (ADCP) measurements capture velocity fluctuations associated with NLIWs ( Chang et al. 2008 ; Lien et al. 2010, manuscript submitted to J. Phys. Oceanogr. ; Alford et al. 2010 ; Ramp et al. 2010 ). NLIWs may have vertical currents as large as O (0.1 m s −1 ) and are often distinct in ADCP vertical velocity records. ADCP velocity measurements
their generation and dissipation sites and for estimating their intensity, energy, and energy flux. Shipboard and moored acoustic Doppler current profiler (ADCP) measurements capture velocity fluctuations associated with NLIWs ( Chang et al. 2008 ; Lien et al. 2010, manuscript submitted to J. Phys. Oceanogr. ; Alford et al. 2010 ; Ramp et al. 2010 ). NLIWs may have vertical currents as large as O (0.1 m s −1 ) and are often distinct in ADCP vertical velocity records. ADCP velocity measurements
1. Introduction The presence of bubbles in a liquid can have a considerable influence on that liquid’s optical and acoustical properties, as well as providing opportunities for the exchange of gases across the bubble boundary. Consequently, accurate measurement of the number and size of the bubbles present is desirable in many fields of science, for example, chemical engineering, medicine, and oceanography. The aim of the research presented in this paper is to improve the measurement of the
1. Introduction The presence of bubbles in a liquid can have a considerable influence on that liquid’s optical and acoustical properties, as well as providing opportunities for the exchange of gases across the bubble boundary. Consequently, accurate measurement of the number and size of the bubbles present is desirable in many fields of science, for example, chemical engineering, medicine, and oceanography. The aim of the research presented in this paper is to improve the measurement of the
1. Introduction a. Manual snow depth measurements In Canada, for all meteorological stations prior to the 1960s, and for most nonsynoptic stations over their entire history, snowboards were used to measure new snow within a specified time period ( Potter 1965 ). The depth of snow on the board was measured with a ruler that, since 1978, has been 1 m long and graduated every 0.2 cm. The board was then reset on the surface of the snow cover to prepare for the next snowfall (SF) event. A limitation
1. Introduction a. Manual snow depth measurements In Canada, for all meteorological stations prior to the 1960s, and for most nonsynoptic stations over their entire history, snowboards were used to measure new snow within a specified time period ( Potter 1965 ). The depth of snow on the board was measured with a ruler that, since 1978, has been 1 m long and graduated every 0.2 cm. The board was then reset on the surface of the snow cover to prepare for the next snowfall (SF) event. A limitation
vulnerability to flooding are both increasing ( Hirabayashi et al. 2013 ; Huang et al. 2015 ). For these reasons, accurate precipitation measurements are needed by watershed managers, hydrologists, emergency management agencies, meteorologists, and climatologists. Solid precipitation measurements, in particular, are subject to large measurement errors, due primarily to undercatch caused by wind ( Fortin et al. 2008 ; Goodison et al. 1998 ; Goodison 1978 ; Rasmussen et al. 2012 ; Sugiura et al. 2003
vulnerability to flooding are both increasing ( Hirabayashi et al. 2013 ; Huang et al. 2015 ). For these reasons, accurate precipitation measurements are needed by watershed managers, hydrologists, emergency management agencies, meteorologists, and climatologists. Solid precipitation measurements, in particular, are subject to large measurement errors, due primarily to undercatch caused by wind ( Fortin et al. 2008 ; Goodison et al. 1998 ; Goodison 1978 ; Rasmussen et al. 2012 ; Sugiura et al. 2003
Wind Direction Measurements on Moored Coastal Buoys1. Introduction Wind measurements collected by anemometers mounted on floating objects are subjected to movements driven by the motion of the sea surface. Despite new technologies such as satellite synthetic-aperture radar (SAR) wind measurements ( Lin et al. 2008 ) that enable the “sea state” determined by winds and waves to be followed, moored stations are still extremely valuable. The definition that separates the ocean or “offshore” buoys and coastal buoys in distinct categories is not
1. Introduction Wind measurements collected by anemometers mounted on floating objects are subjected to movements driven by the motion of the sea surface. Despite new technologies such as satellite synthetic-aperture radar (SAR) wind measurements ( Lin et al. 2008 ) that enable the “sea state” determined by winds and waves to be followed, moored stations are still extremely valuable. The definition that separates the ocean or “offshore” buoys and coastal buoys in distinct categories is not
A UAV–RTK Lidar System for Wave and Tide Measurements in Coastal Zones1. Introduction Airborne scanning lidar is frequently used for mapping topography in coastal areas and for monitoring shoreline variations (e.g., Stockdon et al. 2002 ) and beach erosion (e.g., Sallenger et al. 2003 ). Lidar has been extended and proven to be a useful tool for coastal sea surface (e.g., Reineman et al. 2009 ; Vrbancich et al. 2011 ) and wave dissipation rate measurements (e.g., Huang et al. 2012 ). However, the abovementioned studies rely on massive lidar systems, such as
1. Introduction Airborne scanning lidar is frequently used for mapping topography in coastal areas and for monitoring shoreline variations (e.g., Stockdon et al. 2002 ) and beach erosion (e.g., Sallenger et al. 2003 ). Lidar has been extended and proven to be a useful tool for coastal sea surface (e.g., Reineman et al. 2009 ; Vrbancich et al. 2011 ) and wave dissipation rate measurements (e.g., Huang et al. 2012 ). However, the abovementioned studies rely on massive lidar systems, such as
Coupling of Wave Data and Underwater Acoustic Measurements in a Maritime High-Traffic Coastal Area: A Case Study in the Strait of Sicily. Therefore, in the development of a noise-monitoring plan in marine shallow waters, a comparative study coupling wave data and underwater acoustic measurements contributes to distinguishing the main natural abiotic underwater noise from anthropogenic noise ( Buscaino et al. 2016 ). X-band marine radars are useful active microwave remote sensing systems for sea-state monitoring either offshore or close to the coastline. Sea surface analyses by marine radar are based on the acquisition of consecutive radar
. Therefore, in the development of a noise-monitoring plan in marine shallow waters, a comparative study coupling wave data and underwater acoustic measurements contributes to distinguishing the main natural abiotic underwater noise from anthropogenic noise ( Buscaino et al. 2016 ). X-band marine radars are useful active microwave remote sensing systems for sea-state monitoring either offshore or close to the coastline. Sea surface analyses by marine radar are based on the acquisition of consecutive radar
Turbulence Measurements from Compliant Moorings. Part II: Motion Correction1. Introduction Acoustic Doppler velocimeters (ADVs) have been used to make high-precision measurements of water velocity for over 20 years ( Kraus et al. 1994 ; Lohrmann et al. 1995 ). During that time, they have been deployed around the world to measure turbulence from a range of platforms, including in the laboratory setting ( Voulgaris and Trowbridge 1998 ); from stationary structures on ocean, river, and lake bottoms ( Kim et al. 2000 ; Lorke 2007 ; Cartwright et al. 2009 ); in surface
1. Introduction Acoustic Doppler velocimeters (ADVs) have been used to make high-precision measurements of water velocity for over 20 years ( Kraus et al. 1994 ; Lohrmann et al. 1995 ). During that time, they have been deployed around the world to measure turbulence from a range of platforms, including in the laboratory setting ( Voulgaris and Trowbridge 1998 ); from stationary structures on ocean, river, and lake bottoms ( Kim et al. 2000 ; Lorke 2007 ; Cartwright et al. 2009 ); in surface
Uncertainties in Current Measurements in the Northern North Seawell known. To utilize that the occurrence of extreme wind, waves, and currents are not fully correlated in the design of offshore structures, the new edition of N-003, which is on industry hearing ( NORSOK 2017 ), recommends at least 5 years of simultaneous wind, wave, and current data. Based on this and in order to be able to establish joint distributions for significant wave height and current speed for the design of offshore structures, a met–ocean measurement program at five locations in the
well known. To utilize that the occurrence of extreme wind, waves, and currents are not fully correlated in the design of offshore structures, the new edition of N-003, which is on industry hearing ( NORSOK 2017 ), recommends at least 5 years of simultaneous wind, wave, and current data. Based on this and in order to be able to establish joint distributions for significant wave height and current speed for the design of offshore structures, a met–ocean measurement program at five locations in the
