Geoscience Reference
In-Depth Information
G PALAEOCLIMATES
new statistical techniques and showed that it correlated
well with past temperature records, especially for ocean
palaeotemperatures derived from isotopic (
18
0/
16
0)
ratios in marine organisms.
Prior to the mid-twentieth century thirty years of record
was generally regarded as sufficient in order to define a
given climate. By the 1960s the idea of a static climate
was recognized as being untenable. New approaches
to palaeoclimatology were developed in the 1960s to
1970s. The astronomical theory of climatic changes
during the Pleistocene proposed by Croll (1867), and
developed mathematically by Milankovitch, seemed
to conflict with evidence for dated climate changes.
However, in 1976, Hays, Imbrie and Shackleton recal-
culated Milankovitch's chronology using powerful
H THE GLOBAL CLIMATE SYSTEM
Undoubtedly the most important outcome of work
in the second half of the twentieth century was the
recognition of the existence of the global climate
system (see Box 1.1). The climate system involves
not just the atmosphere elements, but the five major
GLOBAL ATMOSPHERIC RESEARCH
PROGRAMME (GARP) AND THE WORLD
CLIMATE RESEARCH PROGRAMME
(WCRP)
box 1.1
topical issue
The idea of studying global climate through co-ordinated intensive programmes of observation emerged through the
World Meteorological Organization (WMO: http://www.wmo.ch/) and the International Council on Science (ICSU:
http://www.icsu.org) in the 1970s. Three 'streams' of activity were planned: a physical basis for long-range weather
forecasting; interannual climate variability; and long-term climatic trends and climate sensitivity. Global meteorological
observation became a major concern and this led to a series of observational programmes. The earliest was the
Global Atmospheric Research Programme (GARP). This had a number of related but semi-independent components.
One of the earliest was the GARP Atlantic Tropical Experiment (GATE) in the eastern North Atlantic, off West Africa,
in 1974 to 1975. The objectives were to examine the structure of the trade wind inversion and to identify the conditions
associated with the development of tropical disturbances. There was a series of monsoon experiments in West Africa
and the Indian Ocean in the late 1970s to early 1980s and also an Alpine Experiment. The First GARP Global Experiment
(FGGE), between November 1978 and March 1979, assembled global weather observations. Coupled with these
observational programmes, there was also a co-ordinated effort to improve numerical modelling of global climate
processes.
The World Climate Research Programme (WCRP: http://www.wmo.ch/web/wcrp/wcrp-home.html), established
in 1980, is sponsored by the WMO, ICSU and the International Ocean Commission (IOC). The first major global effort
was the World Ocean Circulation Experiment (WOCE) which provided detailed understanding of ocean currents and
the global thermohaline circulation. This was followed in the 1980s by the Tropical Ocean Global Atmosphere (TOGA).
Current major WCRP projects are Climate Variability and Predictability (CLIVAR: http://www.clivar.org/), the
Global Energy and Water Cycle Experiment (GEWEX), and Stratospheric Processes and their Role in Climate (SPARC).
Under GEWEX are the International Satellite Cloud Climatology Project (ISCCP) and the International Land Surface
Climatology Project (ISLSCP) which provide valuable datasets for analysis and model validation. A regional project on
the Arctic Climate System (ACSYS) is nearing completion and a new related project on the Cryosphere and Climate
(CliC: http://clic.npolar.no/) has been established.
Reference
Houghton, J. D. and Morel, P. (1984) The World Climate Research Programme. In J. D. Houghton (ed.)
The Global Climate
,
Cambridge University Press, Cambridge, pp. 1-11.
