A Preliminary Study of Winter Atmospheric River’s Precipitation Characteristics Using Satellite Data over Galicia (NW Spain)

This brief research report is aimed to make a first approach to the study of the type of precipitation associated with a set of atmospheric river (AR) events over the Atlantic region of Galicia. Fifteen ARs that made landfall in the Spanish region of Galicia have been analyzed using the 2B-GEOPROF and 2C-PRECIP-COLUMN from the CloudSat cloud profiling radar (CPR). An estimation of the relative ratio between warm and cold precipitation associated with each event is provided. Broadly speaking, cold precipitation accounts for 80% of the total. This value is slightly higher than the already stated for Pacific AR events. However, similar mean rain rates (0.35 mm/h for the warm precipitation and 1.16 mm/h for the cold counterpart) to those reported by the literature have been obtained. In the absence of a more comprehensive and conclusive statistic, it seems that cold precipitation is predominant along the central axis of a well-developed AR. In this central core of the AR, the bulk of the moisture remains in the lower levels, and the freezing level (FL) is low. According to these results, the interaction between the warm conveyor and the cold conveyor belt may eventually raise the FL to upper levels, leading the warm fraction to play a more important —even though still secondary— role.