Vertical distribution of temperature and humidity over the Caribbean Sea

The observations presented and discussed in this paper were obtained as part of aresearch project conducted under contract NObs-2083 with the Bureau of Ships ofthe U. S. Navy by the Woods Hole Oceanographic Institution. The observationsand their original reduction were carried out under the direction of Jeffries Wyman.The airplane soundings were undertaken by Kenneth McCasland and Alfred Woodcock.The sea surface temperature was measured on the surface ships by David F. Barnesand Roger Patterson. The necessary airplane (PBY-SA) and surface boats (PC's) weremade available by the U. S. Navy.All observations were made during the spring of 1946 at about 19.5°N latitude,66°W longitude, north of San Juan, Puerto Rico, and at about lO°N latitude, 79.5°Wlongitude, north of Coco Solo, Panama. An extensive preliminary report on the results of the expedition with a limited circulation was prepared by Wyman and his collaboratorsduring the summer of 1946.The present paper deals with certain phases of the work in a more detailed fashion.Special attention is given to the temperature and humidity distributions in the verticaland to their interpretation in the light of meteorological principles. A discussion ofatmospheric turbulence based on airplane measurements has already been publishedelsewhere (Langwell, 1948), and an application of the airplane soundings to the theoryof cumulus clouds has been studied by Stommel (1947).The second and third chapters of this publication deal with the description of observationaltechniques used by the expedition, with the methods of reduction and presentthe data on which the later discussion is based. It has been thought desirable to publishthese data in extenso because they may be of interest to other meteorologists in viewof the sparsity of upper-air observations in this region. The actual preparation ofChapters II and III is largely the work of Bunker and Stommel.In order to show how the observations made off Puerto Rico fit into the generalpattern of climatic and weather conditions in the Caribbean area Chapter iv presentsa survey of the climate of this region and of the weather conditions during the time whenthe observations were taken. This Chapter was contributed by Joanne Malkus. It ispertinent to include in this general introduction the conclusion drawn in Chapter IVnamely that the weather situations encountered represented, in general, a relativelyundisturbed trade-wind regime of early spring.The homogeneous layer of nearly dry-adiabatic lapse-rate of temperature and almostconstant mixing ratio is one of the most characteristic phenomena in the lowest atmosphereof this region. It is also of utmost importance for the energy budget of the hydrosphereand the atmosphere. Therefore, a special discussion of this layer by Bunker isgiven in Chapter V.Because of the nearly dry-adiabatic lapse-rate in the homogeneous layer most of theheat transfer between water and air in the trade-wind zone must be in the form of latentheat of vaporization, a conclusion whose thermodynamic implications were discussedthoroughly by Ficker (1936). For this reason the distribution of water vapor deservesspecial attention, and Chapter VI deals with this variable as a problem in turbulent massexchange. The analysis presented in this chapter is due to Haurwitz and Stommel.