BCO LGR Continuous In-Situ Water Vapor Isotopic Composition

During the EUREC4A campaign, a Los Gatos Research (LGR) water-vapor isotope analyzer, using off-axis integrated cavity output spectroscopy (OA-ICOS) was operated at the Barbados Cloud Observatory (BCO) at 13.16°N, 59.43°W from 18 January to 16 February 2020. The instrument was installed alongside a Picarro Water Vapor Isotopic Analyzer in a temperature-regulated container (24±2°C). Both analyzers sampled ambient air from the same protected inlet and heated inlet line. Water vapor isotope data from the LGR were normalized to the VSMOW-SLAP scale using three liquid standards; two were measured once, while a third was introduced during daily checks. The daily standard was interpolated to the raw 1 Hz time resolution and the IAEA procedure (IAEA, 2017) was used to calibrate and account for instrument drift. No humidity-dependence correction was applied to the data. Uncertainty estimates are ±0.41‰ and ±0.94‰ for δ18O and δD respectively. Masked (missing) data represent periods when daily calibration checks or instrument maintenance were performed. All variables have been averaged to 1-minute intervals.