CLIMAP research is advancing along three distinct lines 

 or strategies, each formalized as a program seeking answers to 

 specific questions. 



Global Climate Reconstruction Program 



This program is assembling synoptic arrays of data to 

 reconstruct past changes and near equilibrium states of the 

 global climate. Limitations in the models and within the strati- 

 graphic records will determine the number of reconstructions. 

 Time periods to be mapped are selected to solve specific prob- 

 lems, such as "What were the global climatic characteristics 

 just prior to the onset of the ice age?" Data from the recon- 

 structed climates will be used to improve numerical models of 

 climate and to test and evaluate the accuracy of computer 

 models. 



Regional Climate Dynamics Program 



Objectives of this program are to identify regions and 

 specific mechanisms that play critical or controlling roles in 

 climatic change. For example, changes in global albedo and 

 formation of deep ocean waters are important in high latitudes. 

 The flux of latent and sensible heat to the atmosphere is sig- 

 nificant in lower latitudes. All parts of the global climatic system 

 must be considered, including the interplay between active 

 regions and between active and stable regions. The role of 

 different phases of fluid systems that enter into climatic change 

 will be studied, as will details of the continental atmosphere in 

 low and middle latitudes, the extent of sea and land ice, and the 

 temperature of surface and bottom ocean waters. 



Climatic Time-Series Program 



This program generates time-series of variables considered 

 to be significant indices of climate. The time-series are analyzed 

 for periodicities. They provide a basis for identifying different 

 climatic regimes and for making correlations in the stratigraphic 

 records. For example, qualitative analyses of fluctuations in 

 alpine glaciers have given new insight into climatic change 

 during the Holocene. Quantitative analyses, using spectral and 

 filter techniques, have yielded oxygen isotope curves that reflect 

 changing global ice volume and selected biotic indices that reflect 

 changes in water-mass boundaries (fig. 8). 



Time-series data have been fertile sources of theories on 

 the fundamental causes of climatic change. The 2,500-year 

 cycle of little ice ages, for example, has been interpreted as 

 evidence of a sun and climate link, and the 100,000-year 

 climatic cycle that is evident in many records of the past half- 

 million years has been interpreted as an effect of changes in 

 the Earth's solar orbit. Although neither concept has led to a 

 tested theory of climatic change, the search for mechanisms to 

 explain well-documented cycles will continue. 



Summary of Accomplishments 



Accomplishments of CLIMAP include the following: 



1 . Formation of a interdisciplinary team to study climatic 

 change during the last million years. 



2. Development of techniques to estimate past sea-surface 

 temperatures in all oceans, using four selected faunal and floral 

 groups. 



3. Preparation of a global map of sea-surface temperature 

 18,000 years B.P. (before present). See figure 9. 



Figure 8. — Southward shift of cold Arctic water 18,000 years 

 also suggests there was a more southerly flow of warm Gulf 

 Stream waters across the Atlantic Ocean. 



..-.■■ ' •.■.■.■.•J 90°N 



45°N 



90°E 18,000 Years Ago 



I I Glaciers 

 17?! Sea Ice 

 ^S Land 



0° 



\;M Warm Waters 

 [••3 Temperate Waters 

 Ea Cool Waters 



Figure 9. — Comparison of surface features 18,000 years ago 

 and today. 



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