Muddy Footprints: Satellite's View of Ship Pollution

NASA Earth Observatory
Wednesday, February 13, 2013
Global NOx Map: Image credit NASA

Long tracks of elevated nitrogen dioxide (NO2) levels show up along certain shipping routes when viewed from NASA's Aura satellite.

For more than a decade, scientists have observed “ship tracks” in natural-color satellite imagery of the ocean. These bright, linear trails amidst the cloud layers are created by particles and gases from ships. They are a visible manifestation of pollution from ship exhaust, and scientists can now see that ships have a more subtle, almost invisible, signature as well, according to 'NASA Earth Observatory'.

Data from the Dutch and Finnish-built Ozone Monitoring Instrument (OMI) on NASA’s Aura satellite show long tracks of elevated nitrogen dioxide (NO2) levels along certain shipping routes. NO2, is among a group of highly-reactive oxides of nitrogen , known as NOx, that can lead to the production of fine particles and ozone that damage the human cardiovascular and respiratory systems. Combustion engines, such as those that propel ships and motor vehicles, are a major source of NO2 pollution.

The map shown is based on OMI measurements acquired between 2005 and 2012. The NO2 signal is most prominent in an Indian Ocean shipping lane between Sri Lanka and Singapore, appearing as a distinct orange line against (lighter) background levels of NO2. Other shipping lanes that run through the Gulf of Aden, the Red Sea, and the Mediterranean Sea also show elevated NO2 levels, as do routes from Singapore to points in China. These aren’t the only busy shipping lanes in the world, but they are the most apparent because ship traffic is concentrated along narrow, well-established lanes.

The Atlantic and Pacific Oceans also have heavy ship traffic, but OMI doesn’t pick up NO2 pollution tracks because the shipping routes are less consistent. The shapes of landmasses force ships into narrow paths in the Indian Ocean, while ships in the Atlantic and Pacific tend to spread out over a broad areas as they navigate around storms.

In addition, the air over the northeastern Indian Ocean is relatively pristine. Heavy NO2 pollution (dark red in the map) from cities and off-shore drilling activity along the coasts of China, Europe, and the United States obscures the ship tracks that might otherwise be visible to OMI.

In the map, the Arctic is gray because the lack of light during the winter and frequent cloudiness during the summer prevented OMI from collecting usable data in the area.

Urban areas and industrialization aren’t the only source of NO2 in the map. Agricultural burning in southern Africa and persistent westerly winds make an elevated band of NO2 that stretches from southern Africa to Australia. (In central Africa, easterly winds push pollutants from fires toward the Atlantic, keeping NO2 levels comparatively low over the northern Indian Ocean.) Lightning, which produces NOx, also contributes to background NO2 levels.

Just how much shipping contributes to overall NOx emissions remains an open question for scientists. Research suggests that shipping accounts for 15 to 30 percent of global NOx emissions; scientists are using satellite observations to reduce the uncertainty in such estimates.

Source: NASA Earth Observatory
 

Maritime Reporter September 2013 Digital Edition
FREE Maritime Reporter Subscription
Latest Maritime News    rss feeds

Technology

Wärtsilä Reshuffles Two Top Managers

The following appointments have been made in the management inform Wärtsilä Corporation: Mr Rakesh Sarin (59), B.Sc. (Eng.), has been appointed President of Power Plants,

ABB Celebrates 125th Anniversary in Finland

ABB is celebrating today its 125th anniversary in Finland. Founded in 1889 in Helsinki by entrepreneur and inventor Gottfrid Strömberg, ABB Finland is today

Frost & Sullivan’s Excellence Awards 2014 recognises 18 companies

Frost & Sullivan held its inaugural New Zealand Excellence Awards on 28 August 2014 at Villa Maria, presenting a total of 18 awards to companies across the industries of Food,

Environmental

China's National Carbon Market to Start in 2016

China plans to roll out its national market for carbon permit trading in 2016, an official said Sunday, adding that the government is close to finalising rules

Fukushima Fallout: Resentment Grows

Like many of her neighbours, Satomi Inokoshi worries that her gritty hometown is being spoiled by the newcomers and the money that have rolled into Iwaki since

Frost & Sullivan’s Excellence Awards 2014 recognises 18 companies

Frost & Sullivan held its inaugural New Zealand Excellence Awards on 28 August 2014 at Villa Maria, presenting a total of 18 awards to companies across the industries of Food,

Marine Science

VIKING Saatsea Puts Crew Training in its Place

VIKING Saatsea will be at SMM 2014 to showcase the revolution it has brought about in crew training – moving everything on board to cut costs, speed up certification,

BMT WBM to Showcase TUFLOW at World Bank Seminar

BMT WBM ( (BMT), a subsidiary of BMT Group Ltd, a leading international engineering and risk management consultancy, is delighted to announce that it will be presenting

RWE Dea Helps Cleveland Juniors Reach Goals

Yesterday, a new club house for the Cleveland Juniors Football Club in Middlesbrough in northern England was officially opened. With support from RWE Dea, the

 
 
Maritime Careers / Shipboard Positions Maritime Standards Navigation Offshore Oil Pipelines Pod Propulsion Ship Electronics Ship Repair Ship Simulators Shipbuilding / Vessel Construction
rss | archive | history | articles | privacy | terms and conditions | contributors | top maritime news | about us | copyright | maritime magazines
maritime security news | shipbuilding news | maritime industry | shipping news | maritime reporting | workboats news | ship design | maritime business

Time taken: 0.1868 sec (5 req/sec)