Atmospheric monitoring. A climate physicist using portable air sampling equipment outside the Climate Monitoring and Diagnostic Laboratory (CMDL), at an altitude of 4170 metres on Mauna Loa, Hawaii. The suitcase-sized container holds vacuum flasks, whilst the mast has an air sampling probe fitted to its tip. To take a sample, a pipe from the probe is connected to one of the flasks and a valve opened. Air is drawn into the flask, which is then sealed, allowing the air sample to be stored for later analysis. CMDL is run jointly by the US National Oceanic and Atmospheric Administration (NOAA) and the Scripps Institution of Oceanography of San Diego.