The Second Research Coordination Meeting on Understandingthe Importance of Convective Rain Events and Tracing Their Impact on theCatchment with Isotopes will bring together the participants on the CRP F31007to present the achievements of their individual projects so far (Day 1),linking the projects in a common data base and through joined publications andguidelines (Day 2), technical training on sampling precipitation andgroundwater for analysis of sulfur-35 (Day 3), planning next activities and presentationof outcomes (Day 4). Regarding the training on Day 3, it should be mentionedthat the IHS developed a pre-concentration method for sulfur-35 in the fieldthat is meant to improve access of MS to this important tracer for groundwatervulnerability. Part of the CRP is to test the applicability to a wide range ofgeographic locations. The second RCM will include an in-person training on theIAEA sampling method for sulfur-35, so that CRP participants can send theirsamples to the IHL or analyse them in their laboratory where a LSC isavailable. The data base that can be achieved through this effort will includethe first data on sulfur-35 in precipitation from the tropics and the southernhemisphere and a proof-of-concept of the method developed at the IHL.