RRS Discovery Cruise 227, 15 Apr-16 May 1997. Plankton patchiness studies by ship and satellite: P2S3

This report describes RRS Discovery Cruise No. 227, which was carried out to measure plankton patchiness in the eastern North Atlantic (in the area of 16-20˚W, 47-49˚N), during the period 15 April to 16 May 1997 (the time of the spring bloom). Meteorological, physical, optical, chemical and biological measurements were made using a combination of underway sampling (MultiMet, ADCP, TSG, fluorimeter, nutrients), towed instrumentation (SeaSoar, OPC, Lightfish, LHPR) and on station sampling (CTD, nitrate sensor, water bottles, Satlantic light sensors, vertical nets). Two large scale surveys, and three small scale surveys were carried out during the cruise. Patchiness in both the phytoplankton (measured by the SeaSoar fluorimeter) and the zooplankton (measured by the OPC) distributions was observed. Satellite SST data (from AVHRR) were received in near real time during the cruise, which aided the interpretation of the ship-based observations. Data acquired during the cruise were assimilated into a coupled bio-physical model, which was run on the ship, in an attempt to provide near real time forecasts of the ocean biology and physics in the survey area.