Chicago Water Isotope Spectrometer

Chi-WIS is a mid-infrared tunable diode laser off-axis integrated cavity output absorption spectrometer (ICOS) instrument for measurement of H2O and HDO in the upper troposphere and lower stratosphere. The high precision of the measurement allows detection of small changes in the HDO/H2O ratio that can be used to study water transport pathways and characterize the extent to which convection-driven water vapor perturbations propagate through the UT/LS to contribute to the overall stratospheric water budget. Chi-WIS participated in the 2017 StratoClim campaign onboard the M-55 Geophysica high altitude research aircraft measuring the isotopic composition of water vapor between 12 and 20 kilometers inside the Asian Summer Monsoon anticyclone.