This page compares weather observations made on the Hecla with recent expected values (1961-90 normals). Although observations were made of many meteorological variables, limitations in the data that were published and digitised means that only sea and air temperatures are available for analysis. It is also possible to infer the sea-ice cover the ship experienced and compare that to recent expected values. Both observed and comparative recent values depend both on the date (position in the seasonal cycle) and the position of the ship - here we show time-series comparisons comparing the actual observations with those which would be expected by a hypothetical ship following the same course, at the same time of year, in recent decades.

Sea temperature

Air Temperature

Sea-Ice

The meteorological logs contain no explicit information on the sea-ice cover, but it is possible to make inferences about the state of the sea-ice from the information available. Sea-ice slows the ship down, it is associated with low sea and air temperatures, and complete sea-ice cover increases the air temperature variability (see AT graph above) - effectively switching from a marine to a continental climate. From each of these sources we can make an estimate of the sea ice cover: as proxy observations they are likely to be imprecise, but collectively they give a reasonable indication of the likely state of the ice coverage.

Estimates of local sea-ice coverage from three different proxies (coloured points) and
the range in expected recent sea-ice coverage - max and min values from HadISST for 1961-90.