Fil:Methane Leaking through the Cracks - NASA Earth Observatory.jpg
Opprinnelig fil (1 440 × 960 piksler, filstørrelse: 993 KB, MIME-type: image/jpeg)
Denne filen er fra Wikimedia Commons og kan brukes av andre prosjekter. Informasjonen fra filbeskrivelsessiden vises nedenfor. |
Beskrivelse
BeskrivelseMethane Leaking through the Cracks - NASA Earth Observatory.jpg |
English: The fragile and rapidly changing Arctic is home to large reservoirs of methane, a potent greenhouse gas. As Earth’s climate warms, that methane is vulnerable to possible release into the atmosphere, where it can add to global warming.
Researchers have known for years that large amounts of methane are frozen in Arctic tundra soils and in marine sediments (including gas hydrates). But now a multi-institutional study led by Eric Kort of NASA’s Jet Propulsion Laboratory has uncovered a surprising and potentially important new source of methane: the Arctic Ocean itself. The photograph above was taken by Kort, and it shows leads and cracks in the ice cover of the Arctic Ocean north of Alaska. During five research flights in 2009–10, Kort and colleagues measured increased methane levels while flying at low altitudes north of the Chukchi and Beaufort Seas in a National Science Foundation/National Center for Atmospheric Research (NCAR) Gulfstream V aircraft as part of the HIAPER Pole-to-Pole Observations (HIPPO) airborne campaign. The methane level detected during the flights was about one-half percent higher than normal background levels. But where was the methane coming from? The team detected no carbon monoxide in the atmosphere, which would have been a signature of methane coming from the human combustion of fuels. And based on the time of year, the location, and the nature of the emissions, it was unlikely that the methane was coming from high-latitude wetlands or geologic reservoirs. By comparing the locations of the enhanced methane levels with airborne measurements of carbon monoxide, water vapor, and ozone, the researchers from six institutions pinpointed a source: the ocean surface, in places where there were cracks and openings in the sea ice cover. The cracks were allowing methane in the top layers of the sea to escape into the atmosphere. The team did not detect enhanced methane levels over areas of solid ice. Kort noted that previous studies had detected high concentrations of methane in Arctic surface waters, but no one had predicted that this dissolved methane would find its way into the overlying atmosphere. Scientists are not yet sure how the methane is produced, but Kort suspects biological productivity in Arctic surface waters may be the culprit. “It's possible that as large areas of sea ice melt and expose more ocean water, methane production may increase, leading to larger methane emissions,” he said. “While the methane levels we detected weren't particularly large, the potential source region, the Arctic Ocean, is vast. So our finding could represent a noticeable new global source of methane.” References
|
Dato | |
Kilde | https://earthobservatory.nasa.gov/IOTD/view.php?id=77868 |
Opphavsperson | NASA/JPL/Eric Kort, Alan Buis; NSF, NCAR, NOAA |
Kameraposisjon | 70° 35′ 52,88″ N, 145° 53′ 54,37″ V | Dette og andre bilder på denne posisjonen på: OpenStreetMap | 70.598021; -145.898437 |
---|
Lisensiering
Public domainPublic domainfalsefalse |
This file is in the public domain in the United States because it was solely created by NASA. NASA copyright policy states that "NASA material is not protected by copyright unless noted". (See Template:PD-USGov, NASA copyright policy page or JPL Image Use Policy.) | ||
Warnings:
|
Elementer som er med i denne fila
motiv
19. aug. 2011
70°35'52.876"N, 145°53'54.373"W
image/jpeg
Filhistorikk
Klikk på et tidspunkt for å vise filen slik den var på det tidspunktet.
Dato/klokkeslett | Miniatyrbilde | Dimensjoner | Bruker | Kommentar | |
---|---|---|---|---|---|
nåværende | 23. apr. 2017 kl. 21:06 | 1 440 × 960 (993 KB) | Huntster | Full size from source. | |
2. jul. 2012 kl. 19:03 | 720 × 480 (275 KB) | Dzlinker | == {{int:filedesc}} == {{Information |Description=To download the full resolution and other files go to: [http://earthobservatory.nasa.gov/IOTD/view.php?id=77868&src=flickr earthobservatory.nasa.gov/IOTD/view.php?id=77868&src=...] The fragile and rapi... |
Filbruk
Den følgende siden bruker denne filen:
Metadata
Denne filen inneholder tilleggsinformasjon, sannsynligvis lagt til av digitalkameraet eller skanneren som ble brukt til å lage eller digitalisere det.
Hvis filen har blitt forandret fra utgangspunktet, kan enkelte detaljer være unøyaktige.
Kameraprodusent | Canon |
---|---|
Kameramodell | Canon PowerShot A460 |
Eksponeringstid | 1/320 sek (0,003125) |
F-nummer | f/8 |
Filmhastighet (ISO) | 80 |
Dato og tid for datagenerering | 19. aug. 2011 kl. 17:43 |
Linsens brennvidde | 5,4 mm |
Bredde | 2 592 px |
Høyde | 1 944 px |
Bits per komponent |
|
Pixelsammensetning | RGB |
Retning | Normal |
Antall komponenter | 3 |
Horisontal oppløsning | 180 dpi |
Vertikal oppløsning | 180 dpi |
Programvare brukt | Adobe Photoshop CS5 Macintosh |
Dato og tid for filendring | 8. mai 2012 kl. 16:41 |
Y- og C-posisjonering | Sentrert |
Exif-versjon | 2.2 |
Dato og tid for digitalisering | 19. aug. 2011 kl. 17:43 |
Betydning av hver komponent |
|
Bildekompresjonsmodus | 3 |
Lukkehastighet | 8,3125 |
APEX blenderåpning | 6 |
Eksponeringsbias | 0 |
Maksimal blender | 2,96875 APEX (f/2,8) |
Avstand til subjekt | 2,49 meter |
Målingsmodus | Mønster |
Blits | Blits ikke utløst, automatisk modus |
Støttet Flashpix-versjon | 1 |
Fargerom | sRGB |
Oppløsning i fokalplan X | 13 360,824742268 |
Oppløsning i fokalplan Y | 13 406,896551724 |
Enhet for oppløsning i fokalplan | tommer |
Avkjenningsmetode | Énchipsfargesensor |
Filkilde | Digitalt stillbildekamera |
Tilpasset bildebehandling | Normal prosess |
Eksponeringsmodus | Automatisk eksponering |
Hvit balanse | Automatisk hvitbalanse |
Digitalt zoomomfang | 1 |
Motivprogram | Standard |
Objektiv | 5.4-21.6 mm |
Dato metadata sist ble endret | 8. mai 2012 kl. 12:41 |
Unik ID for originaldokumentet | 435C59BA8246ADBC85AE64F5E3D38837 |