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A mesoscale atmospheric model coupled with a dispersion model is used to establish source‐receptor relationships between the European‐North African aerosol episodes observed over the Caribbean every year during summer and their main sources. The simulation period extends from 15 July to 16 August 1991, concurrent with the flight campaign of the European Project RECAPMA (Millán et al., 1997; Gangoiti et al., 2001). We now extend the simulations to reach the tropical Atlantic and the Caribbean, and we make use of the TOMS aerosol index data (Nimbus 7 satellite) to substantiate the simulations at the regional‐to‐continental scale. Our simulations, based on passive tracer release from selected source regions, show that emissions from southern Europe can either take a full‐Atlantic shortcut to the American coasts or enter the Mediterranean basin eastward to turn back to America following a longer pathway: The emissions cross the southern Mediterranean coast to northern Africa, and then they are vented to the middle troposphere (2000–6000 m MSL), mixed within the Saharan air layer (SAL) and transported westward to the tropical Atlantic (TA) and America. Recirculations around the Atlas Mountains and perturbed conditions over the area modulate the export of the European tracer (and soil dust) into America. We found transit times of 11–12 days for the full Atlantic shortcut and 20–26 days for the longer pathway across northern Africa. Under the simulated conditions, southern Europe can contribute with more than the 50% of its emissions to America, while northern Europe shows longer transit times and less transport efficiency.

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[1] An innovative technique has been developed to assess moisture sources contributing to precipitation. It represents an advance with respect to previously developed methodologies because it allows to discriminate more effectively between terrestrial versus oceanic sources, and also to detect with greater precision the relative importance of remote versus local sources together with the sequence of evaporation associated with a rainfall event. It is based upon the use of a mesoscale model to simulate a selected precipitation episode and a Lagrangian trajectory model to evaluate three-dimensional back-trajectories in order to track the vapor parcels transporting the target precipitation to their surface evaporative sources. An extreme sequence of rainfall events occurred over central Europe between August 11th and 13th is chosen to put the methodology into test. A domain centered in the region and spanning 6372 km in the W-E direction and 5940 km in the N-S direction is chosen to assess moisture sources. Results show the evolving role of various sources throughout the duration of the event, indicating that they shift from the southern to northern and eastern source regions, while a simultaneous decrease of marine sources with respect to terrestrial sources occurs from the onset of the event to its ending phase. The capability of discriminating moisture sources with precision is an important requirement to better understand the mechanisms of extreme rainfalls.