Image:Annual Average Temperature Map.jpg

Description

This is a global map of the annually-averaged near-surface air temperature from 1961-1990. 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. 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 decline ~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 2.0 land surface temperature data set (New et al. 2002) with the 1° NOAA OISST version 2 sea surface temperature data set (Reynolds et al. 2002) and the 2.5° NCEP/NCAR Reanalysis version 1 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 over estimate 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.

Image from Global Warming Art

This image is an original work created for Global Warming Art.

Permission is granted to copy, distribute and/or modify this image under either:

• The GNU Free Documentation License Version 1.2; with no Invariant Sections, Front-Cover Texts, or Back-Cover Texts.
• The Creative Commons Attribution-NonCommercial-ShareAlike License Version 2.5

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Please refer to the image description page on Global Warming Art for more information

Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 only as published by the Free Software Foundation; with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license is included in the section entitled " Text of the GNU Free Documentation License." Català | English | Español | Français | 日本語 | Polski | Português | Русский | Tiếng Việt | ‪中文(简体)‬ | ‪中文(繁體)‬ | +/-

References

• New, Mark, David Lister, Mike Hulme, Ian Makin (2000). "A high-resolution data set of surface climate over global land areas". Climate Research 21: 1-25.
• 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. Climate 15: 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 Society 77 (3): 437–471.