Extending the Antarctic meteorological record using ice-sheet temperature profiles

Two vertical ice temperature profiles from locations in the Antarctic Peninsula unaffected by meltwater are presented. A simple time-dependent heat diffusion-advection model is used to infer broad surface temperature variations in the Antarctic Peninsula over the century prior to the start of local meteorological records. Air temperature records from two representative meteorological stations (Faraday and Halley) are used to determine the ice surface boundary conditions in the later stages of the model runs. Earlier temperature histories are then devised to provide best fits between the modeled and observed ice temperature profiles. Results of the modeling suggest that the surface temperature in the Antarctic Peninsula dropped by 1.6° ± 0.2°C between the beginning of the nineteenth century and the start of the Faraday record in 1944. On time scales of several decades the Faraday air temperature record began during a period colder than the average, and temperatures in the early 1800s were probably very similar to those of today. The use of an air temperature history derived from an oxygen isotope record that was taken from one of the sites is shown to provide a rather poor fit to the ice temperature profile measured at that site.