Dette bildet bør gjenskapes med hjelp av vektorgrafikk som en SVG-fil. Dette har flere fordeler, se Commons:Media for cleanup for mer informasjon. Hvis en SVG-fil med dette bildet er tilgjengelig, vennligst last den opp. Etter opplasting erstatt denne malen med {{vector version available|nytt bilde.svg}}.
This meteorology image was uploaded in the JPEG format even though it consists of non-photographic data. This information could be stored more efficiently or accurately in the PNG or SVG format. If possible, please upload a PNG or SVG version of this image without compression artifacts, derived from a non-JPEG source (or with existing artifacts removed). After doing so, please tag the JPEG version with {{Superseded|NewImage.ext}} and remove this tag. This tag should not be applied to photographs or scans. If this image is a diagram or other image suitable for vectorisation, please tag this image with {{Convert to SVG}} instead of {{BadJPEG}}. If not suitable for vectorisation, use {{Convert to PNG}}. For more information, see {{BadJPEG}}.
This is a global map of the annually averaged near-surface air temperature from 1961 to 1990. Such maps, also known as "climatologies", provide information on climate variation as a function of location.
The tropics, between the Tropic of Cancer and Tropic of Capricorn, have the most direct sunlight and highest temperatures. While the seasonal contrasts in surface temperature are due to the tilt of the Earth axis, there is relatively little variation in the annual average sunlight received throughout this entire tropics, and hence the entire band has similar temperatures. Above the tropics, temperatures fall off more rapidly as one travels towards the Earth's poles, at a rate of approximately 1 °C for every 145 km (1 °F per 50 miles). Permafrost will form at positions where the annual average temperature is below 0 °C.
The other key factor in determining surface temperature is elevation. Surface temperature declines ~1 °C for every 220 m (1 °F per 400 ft) in elevation above sea level. The coldest portions of Earth are the Greenland and Antarctic Ice Sheets, which combine both very high latitude and high elevation.
Data sources
This map was produced by combining the 10' CRU CL 2.0archive copy at the Wayback Machine land-surface temperature data set (New et al. 2002) with the 1° NOAA OISST version 2archive copy at the Wayback Machine sea-surface temperature data set (Reynolds et al. 2002) and the 2.5° NCEP/NCAR Reanalysis version 1archive copy at the Wayback Machine data set (Kalnay et al. 1996). OISST was used for low- and mid-latitude ocean temperatures, but NCEP/NCAR was substituted in sea ice-forming regions, where OISST would overestimate the near-surface air temperature. In addition, a small offset was added in all regions to the OISST sea-surface temperatures to match the NCEP/NCAR air temperatures, and thus account for the difference between ocean and air. NCEP/NCAR was used for Antarctica, since it was the only data set including this region.
Copyright
This image was created by Robert A. Rohde for Global Warming Art.
Det tillates at dette dokumentet kopieres, distribueres og/eller modifiseres under retningslinjene som beskrevet i GNU fri dokumentasjonslisens, versjon 1.2 eller senere utgave utgitt av Free Software Foundation; med alle seksjoner, uten noen forsidetekster og baksidetekster. En kopi av lisensen er inkludert i avsnittet GNU Free Documentation License.http://www.gnu.org/copyleft/fdl.htmlGFDLGNU Free Documentation Licensetruetrue
til å dele – til å kopiere, distribuere og overføre verket
til å blande – til å endre verket
Under de følgende betingelsene:
navngivelse – Du må kreditere verket på passende vis, lenke til lisensen og indikere hvorvidt det har blitt gjort endringer. Du kan gjøre det på enhver rimelig måte, men ikke på en måte som antyder at lisensgiveren støtter deg eller din bruk av verket.
del på samme vilkår – Dersom du remikser, omarbeider eller på annen måte bygger på dette verket, må du kun distribuere resultatet under den samme eller en samsvarende lisens som denne.
Dette lisensmerket ble lagt til filen som del av lisensoppdateringen av GFDL.http://creativecommons.org/licenses/by-sa/3.0/CC BY-SA 3.0Creative Commons Attribution-Share Alike 3.0truetrue
Une deuxième raison pour laquelle la température de surface dépend de la latitude est la variation de l’épaisseur d'atmosphère traversée par les rayons lumineux. Lorsque les rayons sont perpendiculaires à la surface, l'épaisseur d'atmosphère traversée est la plus faible ; la lumière est moins absorbée et moins diffusée par l’atmosphère et la surface reçoit d'avantage d'énergie solaire.
A l’équateur la surface du globe est, côté soleil, perpendiculaire au rayonnement solaire tandis que près des pôles la surface est presque parallèle. L’énergie solaire reçue par unité de surface est donc plus importante près de l’équateur que près des pôles.
Reynolds, R.W., N.A. Rayner, T.M. Smith, D.C. Stokes, and W. Wang (2002). "An improved in situ and satellite SST analysis for climate". J. Climate15: 1609-1625.
E. Kalnay, M. Kanamitsu, R. Kistler, W. Collins, D. Deaven, L. Gandin, M. Iredell, S. Saha, G. White, J. Woollen, Y. Zhu, M. Chelliah, W. Ebisuzaki, W.Higgins, J. Janowiak, K. C. Mo, C. Ropelewski, J. Wang, A. Leetmaa, R. Reynolds, Roy Jenne, Dennis Joseph (1996). "The NCEP/NCAR 40-Year Reanalysis Project". Bulletin of the American Meteorological Society77 (3): 437–471.