Interannual variability of air temperature inversions in ice-free area of northern James Ross Island, Antarctica

Abstract

Air temperature inversions are common features in Antarctica, especially in the interior where they are observed nearly year-round. Large temporal variability of air temperature inversion incidence is typical for the coastal areas and little is known about its occurrence in the Antarctic deglaciated areas. Here we present a 12-year-long time series of near-surface air temperature inversion derived from two automatic weather stations situated at different altitudes (10 and 375 m a.s.l.) in ice-free part of northern James Ross Island (Antarctic Peninsula). The highest monthly relative frequency of temperature inversions during 2006–2017 was observed in July (38%) when the range between minimum and maximum monthly frequencies reached 34%. Both the lowest monthly relative frequency of temperature inversions and the range were found in December with values of 7% and 15%, respectively. The correlation between mean lapse rate and selected mesoscale flow characteristics were tested. The highest correlations were found between lapse rate and specific humidity for the yearly means (0.69 in the 925 hPa pressure level). Negative correlation coefficients were established between lapse rate and air temperature in summer (− 0.65 in the 500 hPa pressure level). Finally, we also used the Weather and Research Forecasting (WRF) model to ascertain its ability to simulate situations as complicated as near-surface air temperature inversion formation in complex terrain. For a strong winter air temperature inversion, simulated air temperature was compared with in situ observations to assess the model performance.