most likely this JMSDF P-3C Orion went on a low level mission over the ocean as this kind of shower is used to get rid of the agressive saltwater that collects all around the fuselage.
P-3C Orion assigned to MFG 3 "Graf Zeppelin" (Navy air wing) at Nordholz AB is seen in very low pass during arrivals on Days of NATO 2016. This Orion is ex RNLAF tc. nr. 312.