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HMS Fury and Hecla 1824-5 - Analysis


This page compares weather observations made on the Fury and Hecla with recent expected values (1961-90 normals). Observations were made of sea-temperature (SST), air-temperature (AT), and Pressure (SLP). It is also possible to infer the sea-ice cover the ships 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.

In all the figures below, observations from the two sources are distinguished by colour: those from the published account are in red, and those from lieutenant Austin's log in blue.

Sea temperature


Observed (coloured dots) and modern equivalent (black line) sea-surface temperatures.
The lower graph shows the range in expected sea-ice coverage - max and
min values from HadISST for 1961-90.

Air Temperature


Observed (coloured dots) and modern equivalent (black line) air temperatures.
The lower graph shows the range in expected sea-ice coverage - max and
min values from HadISST for 1961-90.

Pressure

The seasonal cycle in pressure is much smaller than the short-term variability, so it's not very useful to compare modern averages with point observations. But, just to be consistent, here's the same plot for pressure:


Observed (coloured dots) and modern average (black line) air pressures.

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