History of Oceanographic Sampling at Ocean Weather Station PAPA and LINE P

Excerpt from: Canadian Data Report of Hydrography and Ocean Sciences No. 107. 1992

An Update of the Statistics of Hydrographic/CTD Data taken at Ocean Station P (May 1956-September 1990)

by S. Tabata and W.E. Weichselbaumer

Institute of Ocean Sciences, Department of Fisheries and Oceans, Sidney, B.C. V8L 4B2

Introduction

In recent years the importance of the oceans to global climatic changes has been given much attention and consequently the study of the ocean climatology has received major consideration in global climate studies. Interest in large-scale oceanographic events and general ocean circulation is more widespread than ever before. This shift in interest has necessitated the requirement for examining the ocean within a greater time frame. However, long ocean time series data needed for such a study are not readily available. The sets of data from Station P and Line P along with those from Station M for the Norwegian Sea, are a few of the time series data of sufficient quality and of suitable length to be useful in examining the variability of the oceans, if only for over a period of a few decades.

Ocean Station P (50 00°N, 145 00°W, depth 4220 metres) was operated as an ocean weather station from 19 December, 1949 through 20 June, 1981. The first oceanographic observation there, in the form of a bathythermograph cast, was made on 19 December, 1949 (Leipper et al., 1954). The oceanographic program at Station P and Line P has undergone many changes since then as can be seen from a summary as shown in Table 1.

In view of the importance of long ocean time series the observations at Station P and Line P were continued, although at much less frequent intervals than in the past, after the withdrawal of the weatherships in June 1981. The observations are carried out mainly by the staff of the Institute of Ocean Sciences using, to a large measure, their own ships. The present ship schedule permits only 3 to 4 cruises there per year.

The statistics of representative oceanographic data for Station P and Line P, based on oceanographic observations made during August 1956 through June 1981 by the Canadian weatherships, have been published previously (Tabata and Peart,1985a, 1985b, 1986). Since then observations have continued there to this day (October 1991). The present report comprises the statistics based on data collected during May 1956 through September 1990. It is to be noted that the staff of the University of Washington made observations at Station P during May, June and July 1956 (Scripps Institution of Oceanography of the University of California, 1963). These data have also been utilised in the preparation of the statistics.