A Norwegian Ice Drift Experiment (ICEX) started in 1976 as part of

a national contribution to the polar programmes under the Global Atmospheric

Research Programme (GARP). The main aim of the experiment

is to obtain information on an important climatic parameter: the export of

ice from the Arctic Ocean through the Fram Strait. The project was reorganized

in 1981, and became a joint programme between Norsk Polarinstitutt

and Det norske meteorologiske institutt, also involving cooperation

with the University of Washington's Arctic Ocean Buoy Program.

An ICEX measuring capsule has been developed in cooperation with

Chr. Michelsens Institutt, Bergen, (Vinje & Steinbakke 1976, Nergaard et al.

1985). The capsule operates effectively in the marginal sea ice areas where

it may be subject to frequent ridging and sporadic drift in water. The buoys

were deployed from a boat in a pilot project in 1975, from a Cessna 185

aircraft landing on the ice in 1976 and 1977, and they have been air-dropped

by the Norwegian Air Force from 1978 onwards. Since 1981 data from the

Norwegian buoys have been included in the Arctic Ocean Buoy Program

data reports edited by the Polar Science Center, University of Washington.

The present data report contains drift tracks and daily values of positions,

air pressure (P) mb, air temperatures (TA) about 80 cm above the ice

surface, and temperatures (TB) at the bottom of the ICEX capsule. The

latter information indicates if the measuring capsule is on the ice or in the

water. When free floating, (TB) gives the temperature about 40 cm below the

sea surface.

During the first five years of the experiment, the air pressure

sensors were built at the Norwegian Meteorological Institute, based on an

aneroid and a displacement transducer. Another Norwegian pressure transducer

has been produced by Aanderaa Instruments. This is based on a silicon

chip as sensing element. The Digiquarts pressure sensor from the US

firm Paro Scientific has also been used since 1981. The sensor resolution is

hetter than 0.1 mb, while the system resolution is 0.4 mb within the normal

variation range of the meteorological variables. Series of comparisons in

the field showed that the mean difference between the data obtained via

Nimbus-6 and the readings on a test set was less than 0.1 mb (Vinje 1978).

Later comparisons showed differences of about 1 mb (Vinje 1981). This was,

however, well inside the FGGE requirements.

The temperature is measured with a radiation shielded termistor.

Fenwal UUA 3213. The system resolution is 0.2°C. The ventilation of the

sensor is dependent upon the wind speed, and the sensor signal is also dependent

upon the heating of the capsule. A series of comparisons in the

field showed that the temperatures were correct within ±0.1 °C during

conditions with normal ventilation (Vinje 1981). A comparison on Fram Ill

(Thorndike et al. 1982) during part of April 1981 indicated temperatures

as much as 1 °C - 2°C too high during the warmest part of each day. Otherwise

the daily cycle was well resolved and the temperature readings from the

ICEX buoy agreed well with the met observer's data.

References

=========

Nergaard, N., Vinje, T. & Finnekåsa, Ø. 1985: Report on ice buoys in theArctic and the Antarctic. Report No. 851129-1 from Chr. Michelsens institutt, Bergen.

Thorndike, A. S., Colony, R. & Munoz, E. A. 1982: [Arctic Ocean Buoy

Program. Data Report 1 January 1981 - 31 December 1981]( http://iabp.apl.washington.edu/pdfs/AOBP1981Thorndike.pdf). Polar

Science Center, University of Washington, Seattle.

Vinje, T. E. 1978: Weather and tide observations at Bouvetøya. Norsk

Polarinstitutt [Skrifter 169]( http://hdl.handle.net/11250/173571).

Vinje, T. E. 1981: Meteorological observations from Bouvetøya. Norsk

Polarinstitutt [Skrifter 175]( http://hdl.handle.net/11250/173651).

Vinje, T. E. & Steinbakke, P. 1976: Nimbus-6 located automatic stations

in the Svalbard waters in 1975. [Norsk Polarinstitutt Årbok 1975]( http://hdl.handle.net/11250/172804).