Optimal Integration Times for Lagrangian Studies of Atmospheric Moisture Sources and Sinks

<strong>Lagrangian methods</strong> for estimating sources and sinks of water vapour have increased in importance in recent years, with hundreds of publications over the past decade on this topic. Results derived from these approaches are, however, very sensitive to the integration time of the trajectories used in the analysis. The most widely used integration time is that derived from the average residence time of water vapour in the atmosphere, normally considered to be around 10 days. In this database, we provide <strong>two versions</strong> of the <strong>Optimal Integration Times (OPTs) </strong>for a spatial resolution of <strong>0.25º x 0.25º in latitude and longitude</strong> using data from the European Centre for Medium-Range Weather Forecasts (ECMWF) Interim Re-Analysis (ERA-Interim) for Lagrangian Studies of Atmospheric Moisture Sources and Sinks<strong>: </strong> <strong>Version 1: </strong> includes the <strong>climatological annual and monthly Optimal Integration Times (OPTs)</strong> for the period <strong>1980-2015</strong>. This database version 1 is completely described in: <strong>R. Nieto, L. Gimeno (2019) A database of optimal integration times for Lagrangian studies of atmospheric moisture sources and sinks, Scientific Data 6, 1-10, https://doi.org/10.1038/s41597-019-0068-8 </strong>and you should reference it directly. <strong>Version 2 </strong>provides the <strong>OPTs month-by-month</strong> with <strong>widespread temporal coverage</strong> from <strong>January 1980 - December 2018</strong>. The OPTs are provided as an <strong>individual monthly dataset</strong>. This version 2 is described in <strong>R. Nieto, L. Gimeno (2021) </strong>an Addendum in<strong> Scientific Data 8</strong>, 130; https://doi.org/10.1038/s41597-019-0068-8.