Fróðskaparrit - 01.01.1998, Blaðsíða 311

317
Holocene Palaeoclimatic Reconstruction in
Northern Iceland: Approaches and Results
Endurskipan av holosenum fornveðurlag í Norðuríslandi:
framferðarhættir og úrslit
Johanne Stotter1, Maria Wastl1, Chris Caseldine2 and Thomas Haberle3
1: Institut fiir Geographie, Universitát Innsbruck, Innrain 52, A-6020, Innsbruck,
Phone: +43 51 250 75415, fax: +43 51 250 72895, Austria.
2: Department of Geography, Amory Building, University of Exeter, Exeter, EX44RI, UK
Phone: +44 139 226 3347, fax: +44 139 226 3342.
3: Geographisches Institut, Universitát Ziirich-Irchel,
Úrtak
Tólveðurfrøðiligar skrásetingar í Islandi miðskeiðis í
19. øld eru brúktar til at vísa, at landið hevur verið fyri
bæði veðurlagslágmørkum og veðurlagshámørkum,
sum umboða tað holosena tíðarskeiðið. Tilfarið er brúkt
til at meta um, hvussu stór tey holosenu temperatur-
frávikini vóru, 3 K, og hvussu nógv avfallið broytist,
meira enn 100 %.
Extended abstract
The period since the middle of the 19th cen-
tury, when instrumental meteorological
recording first started in Iceland, has shown
climate conditions close to, or even at, both
Holocene minimum and optimum levels.
The 19th century part of the ‘Little Ice Age’
represents a thermal minimum, whilst the
warmest decades of the 20th century are
close to the estimated Holocene thermal
maximum. A model describing sea-ice-cli-
mate-ELA relationships in Northern Ice-
land for this period has been developed,
providing a calibrated proxy climate record
as a basis for palaeoclimatic reconstruction
for the Holocene as a whole.
erthurerstrasse 190, CH-8057 Zíirich, Switzerland.
Glacier advances in the periods around
4700BP (all dates are in l4C years BP),
around 4200BP, C.3200-3000BP, around
2000BP, around 1500BP and around
1000BP, based on radiocarbon dating and
tephrochronology, mark climatic minima
of the post-Preboreal Holocene, when con-
ditions were comparable to the extremes in
the second half of the 19th century. If it is
assumed that annual mean temperatures ex-
perienced during the 1930s, the warmest in
the observed record, are comparable to the
Holocene thermal optimum, a range of c.
3K can be estimated for the Holocene as a
whole. Studies of variations in the ELAs of
glaciers in the Trollaskagi area of Northern
Iceland over the period of meteorological
observations shown a mean ELA rise of
only 50m, over 200m less than that calcu-
lated from the observed temperature
change of 1.7K in mean summer tempera-
ture, and the range of c. 3K in annual tem-
perature. It is argued that this reflects a dou-
bling of precipitation levels.
Fróðskaparrit 46. bók 1998: 317-318