Jökull - 01.06.2000, Blaðsíða 53

Mass balance and precipitation on the summit plateau of Oræfajökull
Table 1. Mass balance at Öræfajökull 1993-1998 and precipitation at Kvísker.-Afkomaá Öræfajökli 1993-1998
og mœld úrkoma á Kvískerjum.
year of measurement date h m P g/cm3 b o mm P K mm bo/Ptf
1993 31.7. 12.0 0.58 6980 3627 1.9
1994 31.8. 13.2 0.59 7780 3538 2.2
1995 12.6. 10.2 0.56 5750 2835 2.0
1996 12.6. 11.7 0.54 6320 2601 2.4
1997 not measured - - -
1998 14.6. 11.5 (0.54) (6200) 2959 (2.1)
h: Thickness of annual layer
p : Mean density of annual layer
bo- Mass balance at measurement site (net snow accumulation since about September lst in previous year).
Pjí : Precipitation at Kvísker between September lst in previous year and measurement date.
Figure 2. The core extracted on 31. August, 1994. Hvannadalshnúkur is in the background. - Kjarninn sem
tekinn var 31. ágúst, 1994. Hvannadalshnúkur í baksýn.
The pit dug in 1954 was located in Tjaldskarð, a col
on the ridge to the north of the caldera (Figure 1). It
is likely that high winds in the col cause considera-
ble local snowdrift, reducing the accumulation on the
ridge crest. Thus, the accumulation in Tjaldskarð is
probably lower than on the summit plateau of Öræfa-
jökull.
The observed net balance at 1820 m on Öræfa-
jökull is about double the measured precipitation at
Kvísker and four times that measured at Fagurhóls-
JÖKULL No. 48 51