A statistical investigation of the diurnal temperature variation during the polar night at McMurdo Sound, Antarctica

Abstract

It Is observed that normally, during the polar night, 24- hour periods with a clear sky and light to moderate winds have their lowest temperatures in the middle of the period, and the highest temperatures occur at the beginning and end. For cloudy and windy periods, the shape of the temperature curve is reversed, with the maximum temperature occurring near the middle of the period. Despite many efforts by various investigators no physical explanation could be found for this variation. Hisdal discovered that for clear skies and low wind speed, the same shape of temperature variation curve occurs, whether the starting time is 0000 hr, 1200 hr, or 1400 hr. Thus, the abnormal behavior of the temperature variation appears to be influenced primarily by the statistical bias involved in the selection criteria. This investigation, using six years of surface data, divides the diurnal temperature variation for various special types of days into two parts, the meteorological or diurnal variation and the superimposed statistical bias. Finally, the meteorological diurnal temperature variation, based upon all observations during the six year period, is determined. The writer wishes to express his appreciation for the advice and guidance given him by Professor W. van der Bijl of the U. S. Naval Postgraduate School in this investigation.