scholarly journals Slower Ship Speed in the Bahamas Due to COVID-19 Produces a Dramatic Reduction in Ocean Sound Levels

2021 ◽  
Vol 8 ◽  
Author(s):  
Charlotte Dunn ◽  
James Theriault ◽  
Leigh Hickmott ◽  
Diane Claridge
Keyword(s):  
Sperm Whale ◽  
Mitigation Measures ◽  
Automatic Identification ◽  
Identification System ◽  
Density Level ◽  
Underwater Sound ◽  
Sperm Whales ◽  
Ship Traffic ◽  
Sound Levels ◽  
Ship Speed

As underwater noise from ship traffic increases, profound effects on the marine environment highlight the need for improved mitigation measures. One measure, reduction in ship speed, has been shown to be one of the key drivers in reducing sound source levels of vessels. In 2017, a study began to assess the impacts of increasing commercial shipping traffic on sperm whales in Northwest Providence Channel, northern Bahamas, an international trade route that primarily serves the southeast US. Ship data were collected from an Automatic Identification System (AIS) station combined with recordings from an acoustic recorder to measure underwater sound levels and to detect the presence of sperm whales. Here we analyze a subset of these data to opportunistically investigate potential changes in ship traffic before and during the COVID-19 pandemic. These data span one calendar year from October 2019 to October 2020. A pre-COVID-19 dataset of 121 days, from a recorder approximately 2 km from the shipping route was compared to a 134-day dataset collected during COVID-19 from the same site, comprising 2900 and 3181 ten-minute recordings, respectively. A dramatic decrease in ocean noise levels concurrent with changes in shipping activity occurred during the pandemic. The mean pre-COVID-19 power density level in the 111–140 Hz 1/3-octave band was 88.81 dB re 1 μPa (range 81.38–100.90) and decreased to 84.27 dB re 1 μPa (range 78.60–99.51) during COVID-19, equating to a 41% reduction in sound pressure levels (SPL). After differences in seasonal changes in wind speed were accounted for, SPL decreased during the pandemic by 3.98 dB (37%). The most notable changes in ship activity were significantly reduced vessel speeds for all ship types and fewer ships using the area during the pandemic. Vessel speed was highly correlated to SPL and the only ship-based variable that predicted SPLs. Despite the opportunistic nature [i.e., not a standard before-after-control-impact (BACI) study], this study provides a unique opportunity to assess the effectiveness of ship traffic management strategies, such as slowing ships down, to mitigate impacts on marine life in the study area, including local sperm whale populations.

scholarly journals Year-round acoustic presence of sperm whales (Physeter macrocephalus) and baseline ambient ocean sound levels in the Greek Seas

2019 ◽  
Vol 20 (1) ◽  
pp. 208 ◽  
Author(s):  
NIKOLETTA DIOGOU ◽  
HOLGER KLINCK ◽  
ALEXANDROS FRANTZIS ◽  
JEFFREY A. NYSTUEN ◽  
EVANGELOS PAPATHANASSIOU ◽  
...  
Keyword(s):  
Low Frequency ◽  
Weather Conditions ◽  
Sperm Whale ◽  
Distribution Patterns ◽  
Sound Level ◽  
Anthropogenic Sources ◽  
Mitigation Measures ◽  
Physeter Macrocephalus ◽  
Sperm Whales ◽  
Sound Levels

The sperm whale (Physeter macrocephalus) is the largest odontocete occurring in the Greek Seas. However, monitoring thespecies’ spatiotemporal distribution patterns is especially difficult during the winter months when unfavorable weather conditionsoften hinder survey efforts. In the Greek Seas, visual cetacean surveys are typically not conducted between November and March. In a first attempt to collect year-round baseline information on sperm whale occurrence patterns in Greek waters, two Passive Aquatic Listeners (PALs) were deployed for 19 months, at Pylos Station (36.8 N, 21.6ο E) in the Hellenic Trench, and at Athos Station (40.0 N, 24.7ο E) in the North Aegean Trough. Results revealed the year-round presence of sperm whales at Pylos Station with a higher number of detections observed during late spring and throughout the summer. No sperm whale vocalizations were detected at Athos Station. An ambient sound level analysis revealed higher winter and lower summer levels at both sites largely driven by local weather conditions. Results showed that marine life in the Hellenic Trench area was exposed to higher low frequency (< 1 kHz) sound levels (by up to 10 dB re 1 μPa2/Hz). Ambient noise below 1 kHz is frequently dominated by anthropogenic sources including shipping. Ship strikes and noise disturbance constitute major threats for the small, genetically isolated, endangeredsperm whale population. The results of this study are useful for sperm whale conservation efforts in the region and may helppolicymakers in prioritizing mitigation measures, including the establishment of speed limits and rerouting of ship traffic.

scholarly journals Evaluation of AIS reception in Arctic regions from space by using a stratospheric balloon flight

Polar Record ◽  
2011 ◽  
Vol 48 (1) ◽  
pp. 39-47 ◽  
Author(s):  
Jesper Abildgaard Larsen ◽  
Jens Dalsgaard Nielsen ◽  
Hans Peter Mortensen ◽  
Ulrik Wilken Rasmussen ◽  
Troels Laursen ◽  
...  
Keyword(s):  
Barents Sea ◽  
The Arctic ◽  
Automatic Identification ◽  
Identification System ◽  
Balloon Flight ◽  
Ship Traffic ◽  
Arctic Regions ◽  
Increased Risk ◽  
Stratospheric Balloon

ABSTRACTDue to the increased melting season in the arctic regions, especially in the seas surrounding Greenland, there has been an increased interest in utilising these waterways, both as an efficient transport route and an attractive leisure destination. However, with heavier traffic comes an increased risk of accidents. Due to the immense size and poor infrastructure of Greenland, it is not feasible to deploy ground based ship monitoring stations throughout the Greenland coastline. Thus the only feasible solution is to perform such surveillance from space. In this paper it is shown how it is possible to receive transmissions from the Automatic Identification System (AIS) from space and the quality of the received AIS signal is analysed. To validate the proposed theory, a field study, utilising a prototype of AAUSAT3, the third satellite from Aalborg University, was performed using a stratospheric balloon flight in the northern part of Sweden and Finland during the autumn of 2009. The analysis finds that, assuming a similar ship distribution as in the Barents Sea, it is feasible to monitor the ship traffic around Greenland from space with a satisfactory result.

scholarly journals Extension of an assessment model of ship traffic exhaust emissions for particulate matter and carbon monoxide

2012 ◽  
Vol 12 (5) ◽  
pp. 2641-2659 ◽  
Author(s):  
J.-P. Jalkanen ◽  
L. Johansson ◽  
J. Kukkonen ◽  
A. Brink ◽  
J. Kalli ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Particulate Matter ◽  
Exhaust Emissions ◽  
Sulphur Content ◽  
Assessment Model ◽  
Automatic Identification ◽  
Identification System ◽  
Extended Model ◽  
Engine Load ◽  
Ship Traffic

Abstract. A method is presented for the evaluation of the exhaust emissions of marine traffic, based on the messages provided by the Automatic Identification System (AIS), which enable the positioning of ship emissions with a high spatial resolution (typically a few tens of metres). The model also takes into account the detailed technical data of each individual vessel. The previously developed model was applicable for evaluating the emissions of NOx, SOx and CO2. This paper addresses a substantial extension of the modelling system, to allow also for the mass-based emissions of particulate matter (PM) and carbon monoxide (CO). The presented Ship Traffic Emissions Assessment Model (STEAM2) allows for the influences of accurate travel routes and ship speed, engine load, fuel sulphur content, multiengine setups, abatement methods and waves. We address in particular the modeling of the influence on the emissions of both engine load and the sulphur content of the fuel. The presented methodology can be used to evaluate the total PM emissions, and those of organic carbon, elemental carbon, ash and hydrated sulphate. We have evaluated the performance of the extended model against available experimental data on engine power, fuel consumption and the composition-resolved emissions of PM. We have also compared the annually averaged emission values with those of the corresponding EMEP inventory, As example results, the geographical distributions of the emissions of PM and CO are presented for the marine regions of the Baltic Sea surrounding the Danish Straits.

scholarly journals Ice and AIS: ship speed data and sea ice forecasts in the Baltic Sea

2014 ◽  
Vol 8 (6) ◽  
pp. 2409-2418 ◽  
Author(s):  
U. Löptien ◽  
L. Axell
Keyword(s):  
Sea Ice ◽  
Baltic Sea ◽  
Automatic Identification ◽  
Identification System ◽  
Random Component ◽  
The Baltic Sea ◽  
Mixed Effect ◽  
Ice Conditions ◽  
The Baltic ◽  
Ship Speed

Abstract. The Baltic Sea is a seasonally ice-covered marginal sea located in a densely populated area in northern Europe. Severe sea ice conditions have the potential to hinder the intense ship traffic considerably. Thus, sea ice fore- and nowcasts are regularly provided by the national weather services. Typically, the forecast comprises several ice properties that are distributed as prognostic variables, but their actual usefulness is difficult to measure, and the ship captains must determine their relative importance and relevance for optimal ship speed and safety ad hoc. The present study provides a more objective approach by comparing the ship speeds, obtained by the automatic identification system (AIS), with the respective forecasted ice conditions. We find that, despite an unavoidable random component, this information is useful to constrain and rate fore- and nowcasts. More precisely, 62–67% of ship speed variations can be explained by the forecasted ice properties when fitting a mixed-effect model. This statistical fit is based on a test region in the Bothnian Sea during the severe winter 2011 and employs 15 to 25 min averages of ship speed.

scholarly journals Ice and AIS: ship speed data and sea ice forecasts in the Baltic Sea

2014 ◽  
Vol 8 (4) ◽  
pp. 3811-3828
Author(s):  
U. Löptien ◽  
L. Axell
Keyword(s):  
Sea Ice ◽  
Baltic Sea ◽  
Automatic Identification ◽  
Identification System ◽  
Random Component ◽  
The Baltic Sea ◽  
Mixed Effect ◽  
Ice Conditions ◽  
The Baltic ◽  
Ship Speed

Abstract. The Baltic Sea is a seasonally ice covered marginal sea located in a densely populated area in northern Europe. Severe sea ice conditions have the potential to hinder the intense ship traffic considerably. Thus, sea ice fore- and nowcasts are regularly provided by the national weather services. Typically, several ice properties are allocated, but their actual usefulness is difficult to measure and the ship captains must determine their relative importance and relevance for optimal ship speed and safety ad hoc. The present study provides a more objective approach by comparing the ship speeds, obtained by the Automatic Identification System (AIS), with the respective forecasted ice conditions. We find that, despite an unavoidable random component, this information is useful to constrain and rate fore- and nowcasts. More precisely, 62–67% of ship speed variations can be explained by the forecasted ice properties when fitting a mixed effect model. This statistical fit is based on a test region in the Bothnian Bay during the severe winter 2011 and employes 15 to 25 min averages of ship speed.

scholarly journals Ship noise in an urban estuary extends to frequencies used for echolocation by endangered killer whales

2015 ◽  
Author(s):  
Scott Veirs ◽  
Val Veirs ◽  
Jason D Wood
Keyword(s):  
Transmission Loss ◽  
Source Spectrum ◽  
Automatic Identification ◽  
Identification System ◽  
Underwater Sound ◽  
Killer Whales ◽  
Noise Sources ◽  
Low Frequencies ◽  
High Frequencies ◽  
Location Data

Combining calibrated hydrophone measurements with vessel location data from the Automatic Identification System, we estimate underwater sound pressure levels for 1,582 unique ships that transited the core critical habitat of the endangered Southern Resident killer whales during 28 months between March, 2011, and October, 2013. Median received spectrum levels of noise from 2,812 isolated transits are elevated relative to median background levels not only at low frequencies (20-30 dB re 1 μPa2/Hz from 100-1000 Hz), but also at high frequencies (5-13 dB re 1 μPa2/Hz from 10,000-96,000 Hz). Thus, noise received from ships at ranges less than 3 km extends to frequencies used by odontocetes like the southern resident killer whales for communication and echolocation. Broadband received levels (11.5-40,000 Hz) near the shoreline in Haro Strait (WA, USA) for the entire ship population were 111 ± 6 dB re 1 μPa on average. Mean ship speed was 14.4 ± 4.1 knots. Most ship classes show a linear relationship between received level and speed with a slope near +1 dB/knot. Assuming near-spherical spreading based on a transmission loss experiment we compute mean broadband source levels for the ship population of 173 ± 7 dB re 1 μPa @ 1 m without accounting for frequency-dependent absorption. Spectrum, 1/12- octave, and 1/3-octave source levels for the whole population have median values that are comparable to previous measurements and models at most frequencies, but for select studies may be relatively low below 200 Hz and high above 20,000 Hz. Median source spectrum levels peak near 50 Hz for all 12 ship classes, have a maximum of 159 dB re 1 μPa2/Hz @ 1 m for container ships, and vary between classes by about 25 dB re 1 μPa2/Hz @ 1 m at low frequencies (50 Hz), 13 dB re 1 μPa2/Hz @ 1 m at mid-frequencies (1,000 Hz), and 5 dB re 1 μPa2/Hz @ 1 m at high frequencies (10,000 Hz). Below 200 Hz, the class-specific median spectrum levels bifurcate with large commercial ships grouping as higher power noise sources. Within all ship classes spectrum levels vary more at low frequencies than at high frequencies, and the degree of variability is almost halved for classes that have smaller speed standard deviations.

scholarly journals Simulation of Computation Time of Ship Traffic Analysis using Data Clustering for a Vessel Traffic System

2021 ◽  
Vol 1 (4) ◽  
pp. 41-50
Author(s):  
Rahimuddin ◽  
Mehdi Nakisa ◽  
Haryanti Rivai ◽  
Hasnawiyah Hasan ◽  
Husni Sitepu ◽  
...  
Keyword(s):  
Warning System ◽  
Computation Time ◽  
Critical Issue ◽  
Traffic Analysis ◽  
Automatic Identification ◽  
Identification System ◽  
Ship Traffic ◽  
Traffic System ◽  
The North ◽  
Cluster Area

Indonesian water territory is a crossroads of international shipping lanes connecting countries bordering the South China Sea in the north, countries in southern, and countries from western Indonesia. The shipping route goes through the Sunda Strait, Sumbawa Strait, Makassar Strait and Melaka Strait. The shipping lanes are grouped into three main routes called ALKI (Alur Laut Kepulauan Indonsia) I, II, and III. The increase in total number of ships per year with various capacities tends to increases the traffic in the lane and the risk of ship collision. Using AIS (Automatic Identification System) technology with a warning system required to prevent the effect of accidents. Through the Vessel Traffic System (VTS) receive, record, and analysis the traffic data in the covered area. Computation time become a critical issue for ship traffic assessment in the lane. A numerical simulation program developed and analysed the computation time of ship traffic analysis using cluster area method. The result showed a shorter computation time for a more number of cluster area. The computation time increase quadratically with an increase of ships number or objects.

scholarly journals Ship noise extends to frequencies used for echolocation by endangered killer whales

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e1657 ◽  
Author(s):  
Scott Veirs ◽  
Val Veirs ◽  
Jason D. Wood
Keyword(s):  
Transmission Loss ◽  
Source Spectrum ◽  
Automatic Identification ◽  
Identification System ◽  
Underwater Sound ◽  
Killer Whales ◽  
Noise Sources ◽  
Low Frequencies ◽  
High Frequencies ◽  
Location Data

Combining calibrated hydrophone measurements with vessel location data from the Automatic Identification System, we estimate underwater sound pressure levels for 1,582 unique ships that transited the core critical habitat of the endangered Southern Resident killer whales during 28 months between March, 2011, and October, 2013. Median received spectrum levels of noise from 2,809 isolated transits are elevated relative to median background levels not only at low frequencies (20–30 dB re 1 µPa2/Hz from 100 to 1,000 Hz), but also at high frequencies (5–13 dB from 10,000 to 96,000 Hz). Thus, noise received from ships at ranges less than 3 km extends to frequencies used by odontocetes. Broadband received levels (11.5–40,000 Hz) near the shoreline in Haro Strait (WA, USA) for the entire ship population were 110 ± 7 dB re 1 µPa on average. Assuming near-spherical spreading based on a transmission loss experiment we compute mean broadband source levels for the ship population of 173 ± 7 dB re 1 µPa 1 m without accounting for frequency-dependent absorption. Mean ship speed was 7.3 ± 2.0 m/s (14.1 ± 3.9 knots). Most ship classes show a linear relationship between source level and speed with a slope near +2 dB per m/s (+1 dB/knot). Spectrum, 1/12-octave, and 1/3-octave source levels for the whole population have median values that are comparable to previous measurements and models at most frequencies, but for select studies may be relatively low below 200 Hz and high above 20,000 Hz. Median source spectrum levels peak near 50 Hz for all 12 ship classes, have a maximum of 159 dB re 1 µPa2/Hz @ 1 m for container ships, and vary between classes. Below 200 Hz, the class-specific median spectrum levels bifurcate with large commercial ships grouping as higher power noise sources. Within all ship classes spectrum levels vary more at low frequencies than at high frequencies, and the degree of variability is almost halved for classes that have smaller speed standard deviations. This is the first study to present source spectra for populations of different ship classes operating in coastal habitats, including at higher frequencies used by killer whales for both communication and echolocation.

scholarly journals Machine Learning Approaches for Ship Speed Prediction towards Energy Efficient Shipping

2020 ◽  
Vol 10 (7) ◽  
pp. 2325 ◽  
Author(s):  
Misganaw Abebe ◽  
Yongwoo Shin ◽  
Yoojeong Noh ◽  
Sangbong Lee ◽  
Inwon Lee
Keyword(s):  
Machine Learning ◽  
Operating Conditions ◽  
Weather Data ◽  
Automatic Identification ◽  
Identification System ◽  
Learning Approaches ◽  
Speed Prediction ◽  
Accuracy Result ◽  
One Year ◽  
Ship Speed

As oil prices continue to rise internationally, shipping costs are also increasing rapidly. In order to reduce fuel costs, an economical shipping route must be determined by accurately predicting the estimated arrival time of ships. A common method in the evaluation of ship speed involves computing the total resistance of a ship using theoretical analysis; however, using theoretical equations cannot be applied for most ships under various operating conditions. In this study, a machine learning approach was proposed to predict ship speed over the ground using the automatic identification system (AIS) and noon-report maritime weather data. To train and validate the developed model, the AIS and marine weather data of the seventy-six vessels for a period one year were used. The model accuracy result shows that the proposed data-driven model has a satisfactory capability to predict the ship speed based on the chosen features.

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