From the International Business Times: "Climates cientists from the University of Colorado and the University of New Mexico studying the water cycle have successfully deployed a Picarro precision water isotope analyzer at a remote monitoring station near the top of Mauna Loa, Hawaii. Sampling water vapor at this extreme altitude (11,000 feet above sealevel) is notoriously difficult because the water concentration can drop as low a few hundred parts per million. Yet the Picarro G1102-i, which utilizes WS-CRDS (wavelength scanned cavity ring down spectroscopy), is directly sampling the outside air at this location and providing simultaneous measurement of both delta-D and delta-18O every ten seconds. The absolute calibration is checked with liquid water standards every few hours, which confirms that the instrument has virtually no drift over a six day period. During this extended period the standard deviation of all measurements has been 0.65 per mil for delta-D and 0.08 per mil for delta-18O -- levels of absolute precision comparable to laboratory methods using an IRMS (isotope ratio mass spectrometry) instrument.
"Dr. David Noone of the University of Colorado explains, 'While much attention has been focused on the role of CO2 in driving global warming, changes in the water cycle and the amount of water vapor in the air also have a significant impact. Simply stated, we need more water field data, both concentration and isotope ratios. But before the advent of portable isotope analyzers, obtaining water isotope data from a remote site required capturing samples and chemically processing these before separately analyzing them for deuterium and oxygen-18 in two separate mass spectrometers. Until now, this has precluded continuous real-time isotope monitoring.' He notes that the preliminary Mauna Loa data for delta-D and delta-18O are consistent with expected values, and the high frequency variability seen with the G1102-i reveals a richness in the isotope data that could only have bean dreamed of only a few years ago.
"Dr. Joe Galewsky, University of New Mexico Department of Earth and Planetary Sciences, in an interview with Nature added, "Real time isotope tracking could be a new way of detecting fundamental changes in Earth's atmospheric circulation." He points out that Mauna Loa was the obvious place to conduct the experiment because of its high elevation and its location in the subtropics, which is influenced by both tropical and northerly atmospheric currents."
"cc"
6:19:33 AM 
|
|
