| Summary: | The polar ice sheets store valuable information about paleotemperatures. The temperature derived from ice-cores comes from the interpretation of stable water isotopes concentration. The relevant climatic parameter controlling isotopic concentration is the condensation temperature. Since it is assumed that condensation is formed above the lowest temperature inversion layer, the temperature at the top of the inversion has been used as an approximation for condensation temperature. The temperature at the top of the inversion is currently calculated empirically from the annual mean air temperature at the surface. Here, 25 years of upper-air observations at Neumayer Station were used to investigate temperature and humidity inversions. For the first time, the inversions were classified according to the prevailing synoptic condition and height of occurrence. Additionally, a regression model was created to estimate the strength of both surface-based inversion types based on monthly surface observations and synoptic situation. Finally, the above-mentioned assumption of the condensation temperature and level was assessed. The majority of the inversions are found below \SI{2500}{\metre}. For both types of inversion, strength and depth vary seasonally and depending on the weather condition and level of occurrence. Additionally, temperature and humidity inversions present different seasonal cycles of strength, but similar cycles of depth. Furthermore, the proposed set of equations to estimate temperature inversion strength performs better than the existent empirical equation. Moreover, the statistical significant monthly set of equations to estimate the specific humidity strength is better suitable than the ones that did not consider monthly and synoptic condition differences. Regardless of the weather condition, the condensation level height and temperature is better approximated by the height and temperature at the top of surface-based humidity inversions, respectively. by Tiago Silva Masterarbeit University of ...
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