SOUTH POLE

Trends

Solar irradiance measurements, from which AOD anomaly data are derived, are carried out continuously during the summer months (usually October through February or March) at the NOAA/CMDL South Pole station. Aside from the seasonal gaps, the South Pole record is characterized by increases in AOD resulting from the eruptions of the volcanoes El Chichón (Mexico, 1982) and Pinatubo (Philippines, 1991). The effects of the El Chichón eruption were much smaller at this site than at the two Northern Hemisphere NOAA/CMDL monitoring locations; the maximum AOD anomaly reached only 0.07 (during the first two months of 1983) and decayed to background values over 2-3 years. In contrast, the maximum AOD anomaly at the South Pole after the Pinatubo eruption was greater (0.27 in November 1991) than at any of the other three NOAA/CMDL sites, and through the end of 1992, values remained higher than any others recorded at this site before the Pinatubo eruption. It is possible, however, that these large AOD values may partly reflect effects from the eruption of the Chilean volcano, Mt. Hudson, in August 1991.

With the effects of volcanic eruptions removed, the South Pole record is singularly lacking in background variability, and no long-term trend is evident.

South Pole
Antarctica
Ice- and snow-covered plateau
89° 59' S, 24° 48' W
2810 m above MSL

South Pole Optical Depth Graph

• Monthly aerosol optical depth anomalies at the South Pole