Abstract

The time evolution of humidity and temperature above Dome C (Antarctica) has been investigated by considering data from (1) meteorological radiosondes (2005–2017), (2) the microwave radiometer HAMSTRAD (2012–2017), (3) four modern meteorological reanalyses (1980–2017) and (4) the southern annular mode (SAM) index (1980–2017). From these observations (2005–2017), a significant moistening trend (0.08 ± 0.06 kg m−2 dec−1) is associated with a significant warming trend (1.08 ± 0.55 K dec−1) in summer. Conversely, a significant drying trend of −0.04 ± 0.03 kg m−2 dec−1 (−0.05 ± 0.03 kg m−2 dec−1) is associated with a significant cooling trend of −2.4 ± 1.2 K dec−1 (−5.1 ± 2.0 K dec−1) in autumn (winter), with no significant trends in the spring. We demonstrate that 1) the trends identified in the radiosondes (2005–2017) are also present in the reanalyses and 2) the multidecadal variability of integrated water vapor and near-surface temperature (1980–2017) is strongly influenced by variability in the SAM index for all seasons but spring. Our study suggests that the decadal trends observed in humidity and near-surface temperature at Dome C (2005–2017) reflect the multidecadal variability of the atmosphere, and are not indicative of long-term trends that may be related to global climate change.

Highlights

  • The evolution of the Antarctic climate during the second half of the 20th century and the beginning of the 21st century has been intensively investigated, because it directly affects the Antarctic region and indirectly influences the Earth’s geo-biophysical system

  • (1) One of the largest and most rapid warmings recorded on Earth is occurring over the Antarctic Peninsula (Western Antarctica), with values of ~0.5 ◦ C dec−1 since 1950 [1], the absence of warming during the early 21st century seems consistent with the natural variability of the atmosphere [2,3]. (2) Over the Antarctic Plateau (Eastern Antarctica), the temperature trends depend upon the season, with significant cooling in autumn and significant warming in spring [4]

  • Decadal trends computed on yearly-averaged, near-surface temperature and humidity observed by radiosonde from 2005 to 2018 at the South Pole showed a general warming of 1.1 K dec−1 and a general moistening of 0.007 g kg−1 dec−1 [24], with a warming trend occurring in all seasons

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Summary

Introduction

The evolution of the Antarctic climate during the second half of the 20th century and the beginning of the 21st century has been intensively investigated, because it directly affects the Antarctic region and indirectly influences the Earth’s geo-biophysical system. Decadal trends computed on yearly-averaged, near-surface temperature and humidity observed by radiosonde from 2005 to 2018 at the South Pole showed a general warming of 1.1 K dec−1 and a general moistening of 0.007 g kg−1 dec−1 [24], with a warming trend occurring in all seasons.

Data and Method
Seasonal
Decadal Trends of IWV and 10-m Temperature
Decadal Trends in H2 O and Temperature Profiles
Multidecadal Trends over Dome C
Multidecadal Variability over Dome C
10. Multidecadal
Decadal Trends
Conclusions
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