Physiological Climates of California

Werner Terjung University of California, Los Angeles Physiological Climates of California Few areas in the world have put forth as many claims to "ideal" climates as has California. Sweeping statements concerning the "California Climate" are commonly used, especially by chambers of commerce in their attempts to promote their respective areas. For many it has become an article of faith. Since most of these claims and preconceptions are concerned with how man reacts to the climatic environment, a possible examination of such cannot be achieved by utilizing existing traditional climatic systems which predominantly are not centered on the reactions of man. Climates as Dynamic Phenomena It is the thesis of this writer that man feels and reacts to "real" conditions, e.g., maxima and minima of temperatures, humidities, winds, and radiation rather than to averages of temperature and precipitation , especially annual data. He feels sensations of oppressiveness , heat, warmth, comfort, coolness, etc.; he will feel solar radiation strike his skin and be cooled or heated by the effects of air motion . He has also surrounded the concept of comfort with many cultural elaborations. Climates should be viewed as dynamic phenomena which wax and wane with the seasons and íoÚow the sun over this planet's surface. Thus, seasonal or better yet monthly climates need to be depicted . In subsequent paragraphs of this paper only January and July conditions are utilized. 55 56ASSOCIATION OF PACIFIC COAST GEOGRAPHERS Geographical climatology has too long and ineffectually been preoccupied with the interpretation of meteorology and its viewpoints and thus often has acted only as a middleman between the disciplines. Somehow, it was too often assumed that this was all a geographer needed from climatology and that his sole responsibility was to "integrate" it with other geographical variables. This often deteriorated into an encyclopedic listing of climatic data which were supposed to enlighten the reader in some way. Admittedly, climatology can be viewed in many ways, for many purposes, but to be of better service to geographers, weather phenomena should be studied and depicted in their ecological impact on the man-nature ecosystem . Thus, for example, a cyclonic storm can be given different interpretations as a moving biological or ecological disturbance varying in intensity, degrees and types of impact, areal associations, and psychological influences. The bioclimatic pattern resulting from the study of such meteorotropisms could throw light on the temporary and lasting "distortions" of ecological distances and niches. Climates so conceived and fully exploited can be of significant use in many fields and endeavors: medical geography, recreation and tourism, retirement climates, military geography, clothing and housing , education, and in regional studies. This writer developed previously a classification based on human physiological and psychological sensations created by climatic influences. This scheme contains two parts: the Comfort Index integrating temperature and relative humidity data based on daily mean maxima and minima, and the Wind Effect Index combining solar radiation and wind chill effects.1 Both indices are applied to daytime and nighttime conditions for a particular time period, usually a month. By working with a sufficiently large scale, one may combine both indices cartographically into one climatic expression. The Wind Effect Index is considered to be supplementary to the Comfort Index, reasoning that under a given set of circumstances such as overcast skies, shade, nighttime, and calm, the Wind Effect Index does not come into play or does so only partially. Consequently , the Comfort Index, always effective, is considered to be of major importance, relegating to the Wind Effect Index the function of subdividing the various categories of the Comfort Index. 1W. H. Terjung, "Physiologic Climates of die Conterminous United States: A Bioclimatic Clasification Based on Man," Annals, Association of American Geographers, Vol. 56 (1966), pp. 141-179. VOLUME 28 1 YEARBOOK 1 196657 The Comfort Index was derived by superimposing certain categories of comfort upon the psychrometric chart (Figure 1) containing effective temperature lines, wet-bulb and dry-bulb lines, and lines of relative humidity. The categories of comfort were determined and delimited by the writer upon perusal of a variety of existing research in human comfort. The specific Comfort Index for a particular station is derived by plotting the daily mean maximum or minimum dry...