Plume-top altitude time-series during May 2011 volcanic eruption of Grímsvötn, Iceland

Plume-top altitude time series of the volcanic plume during the eruption of Grímsvötn in Iceland 21-28 May 2011. The altitude was estimated from weather radar echo top data from two weather radars, Keflavik and Klaustur. Keflavik radar is a fixed position C-band weather radar close to Keflavik International Airport, at 64°01.583'N, 22°38.150'W. The height of the antenna is 47 m a.s.l. and the distance to Grímsvötn volcano is 257 km. Klaustur radar is a mobile X-band weather radar located close to Kirkjubaejarklaustur, at 63°46.500'N, 17°57.817'W. The height of the antenna is also 47 m a.s.l. and the distance to Grímsvötn volcano is 75 km.

Atmospheric carbon dioxide, methane, deuterium, and calculated Antarctic temperature of EPICA Dome C ice core

Understanding the role of atmospheric CO2 during past climate changes requires clear knowledge of how it varies in time relative to temperature. Antarctic ice cores preserve highly resolved records of atmospheric CO2 and Antarctic temperature for the past 800,000 years. Here we propose a revised relative age scale for the concentration of atmospheric CO2 and Antarctic temperature for the last deglacial warming, using data from five Antarctic ice cores. We infer the phasing between CO2 concentration and Antarctic temperature at four times when their trends change abruptly. We find no significant asynchrony between them, indicating that Antarctic temperature did not begin to rise hundreds of years before the concentration of atmospheric CO2, as has been suggested by earlier studies.