CLIM (or Clym) OF THE CLOUGH, a legendary English archer, a supposed companion of the Robin Hood band. He is commemorated in the ballad Adam Bell, Clym of the Cloughe and Wyllyam of Cloudeslee. The three were outlaws who had many adventures of the Robin Hood type. The oldest printed copy of this ballad is dated 1550.
CLIMACTERIC (from the Gr. κλιμακτήρ, the rung or step of a κλῖμαξ or ladder), a critical period in human life; in a medical sense, the period known as the “change of life,” marked in women by the menopause. Certain ages, especially those which are multiples of seven or nine, have been superstitiously regarded as particularly critical; thus the sixty-third and the eighty-first year of life have been called the “grand climacteric.” The word is also used, generally, of any turning-point in the history of a nation, a career or the like.
CLIMATE AND CLIMATOLOGY. The word clima (from Gr. κλίνειν, to lean or incline; whence also the English “clime,” now a poetical term for this or that region of the earth, regarded as characterized by climate), as used by the Greeks, probably referred originally either to the supposed slope of the earth towards the pole, or to the inclination of the earth’s axis. It was an astronomical or a mathematical term, not associated with any idea of physical climate. A change of clima then meant a change of latitude. The latter was gradually seen to mean a change in atmospheric conditions as well as in length of day, and clima thus came to have its present meaning. “Climate” is the average condition of the atmosphere. “Weather” denotes a single occurrence, or event, in the series of conditions which make up climate. The climate of a place is thus in a sense its average weather. Climatology is the study or science of climates.
Relation of Meteorology and Climatology.—Meteorology and climatology are interdependent. It is impossible to distinguish sharply between them. In a strict sense, meteorology deals with the physics of the atmosphere. It considers the various atmospheric phenomena individually, and seeks to determine their physical causes and relations. Its view is largely theoretical. When meteorology (q.v.) is considered in its broadest meaning, climatology is a subdivision of it. Climatology is largely descriptive. It aims at giving a clear picture of the interaction of the various atmospheric phenomena at any place on the earth’s surface. Climatology may almost be defined as geographical meteorology. Its main object is to be of practical service to man. Its method of treatment lays most emphasis on the elements which are most important to life. Climate and crops, climate and industry, climate and health, are subjects of vital interest to man.
The Climatic Elements and their Treatment.—Climatology has to deal with the same groups of atmospheric conditions as those with which meteorology is concerned, viz. temperature (including radiation); moisture (including humidity, precipitation and cloudiness); wind (including storms); pressure; evaporation, and also, but of less importance, the composition and chemical, optical and electrical phenomena of the atmosphere. The characteristics of each of these so-called climatic elements are set forth in a standard series of numerical values, based on careful, systematic, and long-continued meteorological records, corrected and compared by well-known methods. Various forms of graphic presentation are employed to emphasize and simplify the numerical results. In Hann’s Handbuch der Klimatologie, vol i., will be found a general discussion of the methods of presenting the different climatic elements. The most complete guide in the numerical, mathematical and graphic treatment of meteorological data for climatological purposes is Hugo Meyer’s Anleitung zur Bearbeitung meteorologischer Beobachtungen für die Klimatologie (Berlin, 1891).
Climate deals first of all with average conditions, but a satisfactory presentation of a climate must include more than mere averages. It must take account, also, of regular and irregular daily, monthly and annual changes, and of the departures, mean and extreme, from the average conditions which may occur at the same place in the course of time. The mean minimum and maximum temperatures or rainfalls of a month or a season are important data. Further, a determination of the frequency of occurrence of a given condition, or of certain values of that condition, is important, for periods of a day, month or year, as for example the frequency of winds according to direction or velocity; or of different amounts of cloudiness; or of temperature changes of a certain number of degrees; the number of days with and without rain or snow in any month, or year, or with rain of a certain amount, &c. The probability of occurrence of any condition, as of rain in a certain month; or of a temperature of 32°, for example, is also a useful thing to know.
Solar Climate.—Climate, in so far as it is controlled solely by the amount of solar radiation which any place receives by reason of its latitude, is called solar climate. Solar climate alone would prevail if the earth had a homogeneous land surface, and if there were no atmosphere. For under these conditions, without air or ocean currents, the distribution of temperature at any place would depend solely on the amount of energy received from the sun and upon the loss of heat by radiation. And these two factors would have the same value at all points on the same latitude circle.