M161 Rainwater Isotopic Composition

Rainwater samples were collected using a Palmex RS1 rain sampler (Gröning et al. 2012), installed in a relatively unshielded location on the aft, starboard railing of the navigation deck at ~17.5 m.a.s.l.. The location was chosen to limit the effects of wind interactions with the ship and to avoid obstruction of the area above the sampler by the main mast. The sampler funnel was cleaned regularly. Immediately after rainfall ended, samples were transferred to 2-mL vials, which were filled to minimize headspace, sealed with parafilm, and stored in a refrigerator at ~4° C during the cruise, at ambient temperatures for shipment, and then again in a refrigerator at ~4° C prior to lab measurement. Samples were processed on a Picarro L-2140-i at the University of New Mexico Center for Stable Isotopes. In total 15 rain samples were collected on the Meteor from 20 January to 19 February, representing 15 separate rain events. Bulk uncertainties are ±0.20 and ±0.51 per mil for δ18O and δD respectively. Dataset contains rain onset and rain end times and locations for each event.