HR: 16:50h
AN: C22B-04    [PDF]
TI: Climate Reconstructions Derived From Global Glacier Length Records
AU: * Klok, L
EM: e.j.klok@phys.uu.nl
AF: IMAU, Utrecht University, Princetonplein 5, Utrecht, 3584 CC Netherlands
AU: Oerlemans, J
EM: j.oerlemans@phys.uu.nl
AF: IMAU, Utrecht University, Princetonplein 5, Utrecht, 3584 CC Netherlands
AB: Glaciers have fluctuated in historic times and the length fluctuations of many glaciers are known. These length records provide useful information about past climate. In order to derive a climate signal from numerous glacier length records, a model is needed that takes into account the main characteristics of a glacier, but uses little information about the glacier itself. Therefore, we developed a simple analytical model. It calculates a climate reconstruction described in terms of a reconstruction of the equilibrium line altitude (ELA) or the mass balance. The model takes into account the geometry of the glacier, the length response time and the mass balance-surface height feedback. It was tested on seventeen European glacier length records. The results reveal that the ELA of these glaciers increased on average 54 m between 1920 and 1950. We then derived historic fluctuations in the ELA on the basis of nineteen glacier length records from different parts of the world. The results show that all glaciers of our data set experienced an increase in the ELA between 1900 and 1960. Between 1910 and 1959, the average increase was 33 m. This implies that during the first half of the twentieth century, the climate was warmer or drier than before. The ELAs decreased to lower elevations after around 1960 up to 1980, when most of our ELA reconstructions end. These results can be translated into a global temperature increase of about 0.8 K for the period 1910-1959.
DE: 1600 GLOBAL CHANGE (New category)
DE: 1827 Glaciology (1863)
DE: 5416 Glaciation
SC: Cryosphere [C]
MN: 2003 Fall Meeting