Overview
In this appendix to Trends in Global Temperature, we examine monthly anomalies, seasonal anomalies, and mean global temperature in degrees centigrade. The Northern Hemisphere has generally warmed more than the Southern. This gap emerged in about 1920, disappeared between 1965 and 1990, but has re-emerged. Warming in the Northern Hemisphere has been most severe in the Arctic. Between 1920 and 1960, the Arctic was warmer than normal, and the Antarctic was colder than normal. Since 1980, both Arctic and Antarctic have been warmer than normal, with the greatest warming occurring in the Arctic.
Monthly Analysis of Global Temperature Anomalies, 1880-2007
In the analysis below, we examine monthly changes in
anomalies.
Seasonal Temperature Anomalies
We grouped anomalies into the four seasons, to see
whether the warming has been uniform. We find
that spring has warmed the most (-1312.43 + 0.675367 x),
followed by winter (-1266.02 + 0.65162 x), then summer
(-1182.94 + 0.609115 x) then fall (-1044.01 + 0.5385 x).
Mean Global Temperature, Degrees Centigrade
In the analysis below, we have used NASA's GISS Surface Temperature Analysis, and converted their anomaly data to degrees centigrade. The GISS analysis of global surface temperature, documented in the scientific literature, incorporates data from three data bases made available monthly: (1) the Global Historical Climatology Network (GHCN) of the National Climate Data Center, (2) the satellite analysis of global sea surface temperature of Reynolds et al., and (3) Antarctic records of the Scientific Committee on Antarctic Research (SCAR)
Sources : GHCN 1880 - 11/2008 meteorological stations, using elimination of outliers and homogeneity adjustment.Downloaded from http://data.giss.nasa.gov/gistemp/tabledata/GLB.Ts.txt.
Variations by Latitude
NASA reports annual mean land-ocean temperature index in .01 C anomalies for selected zones. Their sources include GHCN (Novwember, 1880-2008), HadISST1 (November, 1880-1981), and Reynolds v2 (December 1981-November 2008). They used an anomaly base period of 1951-1980, eliminated outliers, and did a homogeneity adjustment.
The first graph below shows that the Northern Hemisphere has generally warmed more than the Southern. This gap emerged in about 1920, disappeared between 1965 and 1990, but has re-emerged.
The second graph below shows the warming in the Northern Hemisphere has been most severe in the arctic. The four lines depict anomalies from the equator to 24 degrees N., 24-44 N., 44-64 N, and 64-90 degrees N.
A third graph compares the Arctic and Antarctic anomalies. Between 1920 and 1960, the Arctic was warmer than normal, and the Antarctic was colder than normal. Since 1980, both Arctic and Antarctic have been warmer than normal, with the greatest warming occurring in the Arctic.
Source: http://data.giss.nasa.gov/gistemp/tabledata/ZonAnn.Ts+dSST. txt
References
Hansen, J., R. Ruedy, J. Glascoe, and Mki. Sato, 1999: GISS analysis of surface temperature change. J. Geophys. Res., 104, 30997-31022, doi:10.1029/1999JD900835. http://pubs.giss.nasa.gov/abstracts/1999/Hansen_etal.html
Peterson, T.C., and R.S. Vose, 1997: An overview of the Global Historical Climatology Network temperature database. Bull. Amer. Meteorol. Soc. 78, 2837-2849.
Reynolds, R.W., and T.M. Smith, 1994: Improved global sea surface temperature analyses. J. Climate 7, 929-948.
Scientific
Committee on Antarctic Research (SCAR), www.scar.org.
Other Papers in this Series
- Tipping Points. The notion that the planet's climate has now reached a tipping point, and has begun to change on its own, is conjecture. But there are reasons to think a tipping point has been reached.
- Trends in Biodiversity Overall declines in terrestrial, marine, and freshwater animal populations; declines in tropical forests, dryland systems, and grasslands; declines in Neotropical, Afrotropical, and Indo-Pacific regions; declines in birds and mammals. Last revised Wednesday, January 7, 2009.
- Thawing Permafrost In southern Alaska, the permafrost has gone from 0 days per year above freezing in 1987 to 139 days above freezing in 1993. Last revised Wednesday, January 14, 2009.
- Trends in Atmospheric Carbon Dioxide There has been a geometric growth in atmospheric carbon dioxide since the Industrial Revolution, whether measured through Ice Cores, at Mauna Loa, or at marine sea surface sites. Last revised Wednesday, January 7, 2009.
- Trends in Atmospheric Methane The concentration of methane (CH4), the most abundant organic trace gas in the atmosphere, has increased dramatically over the last few centuries, more than doubling its concentration. Atmospheric methane levels of the past 150 years far higher than those of the previous 420,000 years, and are currently 2.5 times as high as any previous level. Last revised Wednesday, January 7, 2009.
- Trends in Global Temperature: Appendix In this appendix to Trends in Global Temperature, we examine monthly anomalies, seasonal anomalies, and mean global temperature in degrees centigrade. The Northern Hemisphere has generally warmed more than the Southern. This gap emerged in about 1920, disappeared between 1965 and 1990, but has re-emerged. Warming in the Northern Hemisphere has been most severe in the Arctic. Between 1920 and 1960, the Arctic was warmer than normal, and the Antarctic was colder than normal. Since 1980, both Arctic and Antarctic have been warmer than normal, with the greatest warming occurring in the Arctic. Last revised Sunday, January 11, 2009.
- Trends in Global Temperature For the 2000 years prior to 1880, the earth was cooler than it now is, and was cooling. However, a growth curve best describes measured global temperatures since 1880. The ten warmest years on record have occurred in the 12-year period 1997-2008, and the pace of warming may be increasing. While mean temperature is now rising rapidly, seasonal variability appears to be decreasing. Last revised Wednesday, January 14, 2009.
- Trends in Snow and Ice Cover In the Northern Hemisphere, the average snow extent has decreased by 3.75 million square Km in the last 39 years. The greatest loss of snow cover has occurred in the months of June and July. In the Northern Hemisphere, the average extent of sea ice decreased by 1.5 million square Km during the period 1978-2008, from about 9.9 million square Km to about 8.4. In the Southern Hemisphere in this period, the extent of sea ice did not change significantly. Reduced snow and ice cover changes albedo, increasing the rate of warming. Last revised Friday, January 16, 2009.
- "Anthropogenic": A Look at Critical Correlates of Human Population Growth abstract Last revised Wednesday, January 14, 2009.
© 2009 David Stang. All rights reserved. Dr. Stang is available for presentations on this topic. Contact him by email. |
Last Revised: Sunday, January 11, 2009