Middle-latitude climates - The Global Climate System: Patterns, Processes, and Teleconnections - page 126

by data quality and availability. Currently, with the availability of models, grid
systems, reanalysis and the like, a much greater understanding prevails. But
there remain problems, not the least of which relate to current trends in amounts
and variability. Much research remains to be completed.
As technology has developed, so have indirect methods for assessing long-term
precipitation patterns. For example, using tree-ring analysis, Haston and Michaelsen
( 1997 ) developed a 400-year history of precipitation for the area between San
Francisco and the US-Mexican border. They concluded that the last 100 years
has experienced higher amounts, with less variability, than the previous periods.
The process of mid-latitude circulation is sometimes defined as operating
separately from the rest of the global circulation. In reality, influences from both
the tropics (SOI for example) and the poles (CPV for example) play important
roles, blurring the geographical boundaries within the overall climate system.
4.8 Examples of mid-latitude websites
The NOAA homepage, www.noaa.gov may be used as the entry to a wealth of
climatic information for many world areas and topics.
Climate diagnostic information is located at cdc.noaa.gov/index.html. The site
provides forecast products and archives for various data series including SSTs.
www.ipcc.ch/ is the home page of the International Panel on Climate Change
and provides an abundance of information about organizations and publications.
WorldWeather Information Service, www.worldweather.org/, provides climat-
ological information and data for many middle-latitude and other world areas.
Southern Hemisphere climate information can be obtained from the
Australian Bureau of Meteorology website (www.bom.gov.au). There are simi-
lar sites for South Africa and New Zealand.
4.9 References
Alexandersson, H. and Moberg, A., 1997. Homogenization of Swedish temperature data.
Part 1: Homogeneity test for linear trend. International Journal of Climatology, 17, 25-34.
Barry, R. G. and Perry, A. H., 1973. Synoptic Climatology: Methods and Applications. London:
Methuen.
Bigg, G., Jickells, T. and Osborn, T., 2003. The role of the oceans in climate. International
Journal of Climatology, 23, 1127-1160.
Chen, T. and Yen, M., 1997. Interdecadal variation of the Southern Hemisphere circulation.
International Journal of Climatology, 10, 805-812.
Cullather, R. I. and Lynch, A. H., 2003. The annual cycle and interannual variability of
atmospheric pressure in the vicinity of the North Pole. International Journal of
Climatology, 23, 1161-1183.
Cusbasch, U. et al., 2001. Projections of future climate change. In J. T. Houghton et al. eds.,
Climate Change 2001: The Scientific Basis. Contributions of Working Group I to the
Third Assessment Report of the IPCC. Cambridge: Cambridge University Press.