WORLD METEOROLOGICAL ORGANIZATION WORLD METEOROLOGICAL ORGANIZATION TECHNICAL NOTE No. 2 TECHNICAL NOTE No. 103 METHODS OF OABSERVATION AT SEA SEA-SURFACE TEMPERATURE Lecture presented during the scientific discussions at the fifth session of the PARTCommission I – SEA SURFACE for Maritime TEMPERATURE Meteorology WMO-No.WMO-No. 247. 26. TP. TP. 135 8 Secretariat of the World Meteorological Organization – Geneva – Switzerland WORLD METEOROLOGICAL ORGANIZATION TECHNICAL NOTE No. 103 SEA-SURFACE TEMPERATURE Lectures presented during the scientific discussions at the fifth session of the Commission for Maritime Meteorology un C 55I.526.6 IWMO - No. 247. TP. 1351 Secretariat of the World Meteorological Organization • Geneva • Switzerland 1969 © 1969, World Meteorological Organization NOTE The designations employed and the presentation of the material in this publication do not imply the expressiun of any opinion whatsoever on the part of the Secretariat of the World Meteorological Organization concerning the legal status of any country or territory or of its authorities, or concerning the delimitation of its frontiers. III TABIE OF CONTENTS Foreword •••••••••••••••.•••..•.••••.•••••••• "....................................... V Summary (Englisp, French, Russian, Spanish). •.. .• ..•••••••.•.. •• ••••.•..••••..••..• •• VII Use of sea-surface temperature in long-range prediction (by Jerome Namias (U.S.A.» 1 Collection and dissemination of sea-surface temperature data for the north-west Pacific and their utilization for fisheries (by Iehiro Imai (Japan» •••••.•••••.••.• 19 Sea-temperature structure and its relation to the United States tuna fisheries in the eastern Pacific Ocean (by Glenn A. Flittner (U.S.A.» 37 Sea-surface temperature patterns in the north-east Atlantic (by J. D. Booth (U.K.». 77 Variations de la temperature de la mer au voisinage de la surface (by J. Romer (France» 97 Sea-surface temperature; some instruments, methods and comparisons (by A. B. Crawford (South Africa» .. 117 CpaBHHTeJIbHble H3MepeHHR TeMl1epaTypbl IioBepxHocTH BO,llbl (TITB) B CCCP (r.M. TayCiep (CCCP)) 131 The comparative measurements of sea-surface temperature in the U.S.S.R. (by G. M. Tauber (U.S.S.R.» 141 v FOREWORD At its Fifth Session, in 1968, the Commission for Maritime Meteorology conducted a series of scientific discussions based on a series of invited lectures on the measurement of sea-surface temperature and the uses of such measurements. The lecturers were selected in the light of their specialized knowledge in particular aspects of this question. The table of contents of the present publication in itself indicates the wide and interesting range of topics covered. The discussions i~volved the many ways of measuring sea-surface temperature, including their respective advantages and disadvantages, the ways in which observations of sea temperature, both surface and sub-surface, may be used to in­ crease s~gn1ficantly the harvest from the sea, the persistency of ocean temperature patterns, and the uses of sea temperature measurements in long-range weather prediction. In view of the great interest expressed in the various papers that were presented and to enable them to be read by scientists who were unable to attend the session, it has been decided to include these papers in the present Technical Note. It should be mentioned that two of the lectures presented at the session have not been reproduced here since their substance has been, in most part, presented elsewhere. These lectures concerned "Numerical Synoptic Analysis of Sea-surface Temperaturell and the "Barbados Oceanographic and Meteorological Experimentl1 by P. M. Wolff and F. Ostapoff respectively. I should like to take this opportunity of expressing my sincere appreciation to all of the experts who presented papers and especially to Dr. M. Rodewald (Federal Republic of Germany) whose untiring efforts and devotion in organizing the scientific discussions provided the main inspiration of this most successful programme. t:::>.~c. ••- (D. A. DaVies) Secretary-General VII SUMMARY Use of sea-surface temperature in long_range prediction The problems associated with complexly"coupled systems such as the oce~ and- the atmosphere are so difficult to solve that it is not yet possible to lay down a set of reli-­ able forecasting rules, especially with regard to long-range forecasting, where the response time of one medium to the other is not known. In spite of these gaps in knowledge there seems to be sufficient order in large-scale air-sea interaction over periods of months and seasons, so that some qualitative use of this information can be helpful in prediction. Dr. Namias, in his paper, suggests some large-scale and cumulative air-sea interactions which seem to have influenced wind and wave patterns over months and seasons during the 1960s. While some of these concepts ~re copsid~red in the routine preparation of five-day~ monthly and season~ forec~sts, Dr. Namiasshows that, they are used mainly to support or negate other indications derived purely from meteorological data. Collection and dissemination of sea-surface temperature data for the north-west Pacific, and their utirization for fisheries Dr. !mai devotes some time to an explanation of the sources, quantity andqua4ity of marine env~ronmental information available to Japan. From this information, a ten-,day surmnary of the sea-surface temperature for one-degree squares is prepared. In additiop, charts of surface currents, underwater temperatures and other elements are prepared on a monthly basis and disseminated by facsimile. Dr. Imai shows that an evaluation of.,this in~ formation has greatly helped t'o explain the cool swnm'ers which occasionally frequent Japan~' Dr. Imai also introduces some examples to show how the" Japanese fishermen utilize this in­ formation for their own special purposes." Sea-temperature structure and its relation to the United States tuna fisheries 'in" the' eastern Pacific Ocean The problem that has plagued the United States tuna-fishing industry has been locating the fish. Fluctuations in distribution have varied greatly; and because of the large areas involved, locating fish concentrations has become a major problem. The nature and degree of movement of fish are highly variable from year to year, and Dr. Flittner relates these variations to changes in oceanography conditions; namely, the cycle in the changing pattern of sea-surface temperature." Dr. Flittner also stresses the other feat- ures of which the fisherman must have knowledge: the vertical structure of the upper layer of the sea. When the upper layers are relatively cold, the fish will not dive and are easily caught. However, when the thermocline is deep, the fish have an environment conducive to eScape from the nets used in pursuing operations. Dr. Flittner then emphasizes the point that there is a close relation between the actual water temperature and where the fish are found, and the fishing industry would benefit greatly from having this kind of sea informa­ tion placed at its disposal, both observed and forecast. Considerable attention is then devoted to the problems related to forecasting for the fishing industry and the challenges that lay ahead. Sea-surface temperature patterns in the north-east Atlantic In his presentation, Captain Booth outlines some of the problems which the Royal Navy has encountered in the routine synoptic analysis of sea-surface temperature over parts of the north-east Atlantic. He mentions some of the characteristics and peculiarities of SST patterns which have been noticed; both with regard to persistency and with regard to change. VIII SUMMARY Temperature variation at the near surface of the sea I Precise measurements of temperatures in the near surface layer of the sea were carried out at open sea where no disturbing effect from coast, ships or platforms is ob­ served; such measurements should permit to assess the value and representativeness in a synoptic sense of an observation and to define what is known as "sea-surface temperature". The temperature profile in the first five metres -- i.e. at" 0.1, 0.5, 1, 2, 3, 4 and 5 metres _ was investigated using a thermometer with an accuracy of O.02% .03°C. The difference Cd) in the temperatures between TO.I-T5 - Le. between 0.1 m and 5 m - obtained from 3,614 observations was as follows: 1,540 observations d $ O.l°e 253 observations 0.1 < d $ 0.2°e 428 observations 0.2 < d $ O.5°e 1,393 observations 0.5 < d Further, variation of vertical thermal structure with time (diurnal change) and the results of comparison of measurements using bucket and thermometer are discussed. Sea~surface temperature; some instruments, methods and comparisons Mr. Crawford examines the meaning of sea-surface temperature, the ways in which it may be measured and the advantages and disadvantages of the various methods used. Mr. Crawford acknowledges the complexity of the problems involved, and admits that the choice ofa suitable instrument is dependent upon a number of factors, some of which are completely lUlrelated. The comparative measurements of sea-surface temperature in the U.S.S.R. Prof. Dr. Tauber also considers the technical definition involved in measuring sea-surface temperatures. His paper deals with measurements made in different climate areas (Pacific Ocean and Indian Ocean) as well as the various conditions of the ship (drifting or lUlder way). A great variety of instruments were tested, and the paper deals in some great detail with the comparison of the readings obtained.