Ignoring plateau icefield contributions to coupled plateau-icefield-outlet-glacier systems can seriously affect ELA reconstruction. Figure 20.2 plots the plateau area as a percentage of the coupled plateau-icefield-outlet-glacier system against the altitu-dinal shift in ELA resulting from inclusion of the plateau icefield area. Figure 20.2a shows results from the reconstructed LIA
maximum glaciers in the southern Lyngen Peninsula, Norway, where ice supply from icefield to valley was mainly by avalanch-ing. The ELA shifts shown in Fig. 20.2a reduced the equilibrium winter accumulation rates by up to 20% (Rea et al., 1998). Figure 20.2b presents evidence from the Younger Dryas reconstruction of 0ksfjordj0kelen, North Norway. The plateau contributing areas are larger, resulting in greater ELA shifts. It is obvious from Fig. 20.2 that climate reconstructions ignoring plateau icefield contributions become increasingly erroneous as the plateau contribution increases.
Glaciers, oceans, atmosphere and climate
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