Meteorology

“ There they would sit, keeping strict, dragon-like watch over the dear little creatures who responded to the names of Anita, Victoria, Concepcion, Guadalupe, or Mercedes, and preventing conversation upon any subject excepting the weather, in which we became so expert that it is a wonder the science of meteorology hasn’t made greater advances than it has during the past two decades. ”

“ DURING the last thirty years the data of meteorology have been accumulated with a very great rapidity, and the chief desideratum of the moment is, to construct with these data such a general theory of the circulation of the atmosphere as would embody the distribution of heat, pressure, moisture, and winds over the surface of the earth, and represent them as consequences of well-established mechanical laws. ”

“ Happily, our meteorologists are at length beginning to define with growing clearness and confidence the laws which underlie and regulate the complicated and ever varying phenomena which we call the weather, and many of these laws, like most natural laws, are beautiful in their simplicity. Although ‘weather wisdom’ is as old as history itself, the science of the weather or meteorology is a growth of the last few years. The weather wisdom of our forefathers may in the light of present knowledge be divided into sense and nonsense. ”

“ This means, simply, that meteorology will soon rank among the exact sciences. The climate of any place in the world, even if no observations have been as yet taken there, can even now be approximately defined. ”

“ Whence it follows that the most important problem of meteorology is the investigation of the causes and consequences of the disturbance of indifferent equilibrium of the atmosphere, and the weightiest problem in weather prediction is the investigation of the geographical origin or extraction of air currents pursuing their course above us toward the pole. ”

“ The observational basis of meteorology is the frequent and, if possible, continuous record of the temperature, moisture and barometric pressure at different altitudes in the free atmosphere, the direction and velocity of the wind, the rain and snow-fall, and the kind, amount and motion of the clouds. ”

“ The fact that there are great traveling vortices or swirls in the atmosphere, which, in whatever regions they occur, partake of135 the general drift of the air around the globe, has been known for about a century, and constitutes the corner stone of practical meteorology. ”

“ The hottest surfaces, even at the rainless portion, where there is no vortex, no storm, and no wind but the continual uniform N. E. horizontal trade-wind, never created, by reason of the heat alone, a mile of wind, a storm or shower.
But, again, the belt of calms, where the air is supposed to rise and create a suction which draws the trades on either side a distance of from one thousand to two thousand miles, an average of three thousand miles in all, at least, is not itself, on an average, over five hundred miles in breadth from north to south. What a wonder of meteorology is here! ”

“ And this is the great principle on which the science of meteorology rests, not only as to winds, but as to weather changes.
Of the sun’s rays which reach the earth, those that fall on the land are absorbed by the surface layer of about 4 feet in thickness. But those that fall on the surface of the ocean penetrate, as shown by the observations of the Challenger Expedition, to a depth of about 500 feet. Hence, in deep waters the temperature of the surface is only partially heated by the direct rays of the sun. In mid-ocean the temperature of the surface scarcely differs 1° Fahr. ”

“ That time may come; for progress is yet to be read in the front of meteorology, and simultaneous practical observations made and interchanged at every important point on the globe. Nevertheless, the seasons have a character—often a regular one—one class of storms prevailing over all others—one series of phenomena occurring to the exclusion of others—and we must regard it if we would arrive at intelligent estimates of their future condition. ”

“ The development of meteorology, in both its scientific and its practical aspects, is intimately dependent upon the progress of our knowledge of physics, and its study offers innumerable problems that can be solved only by proper combinations of mathematical theory and laboratory experimentation. The professors in colleges and universities who have hitherto lectured on this subject have not failed to develop some features of dynamic meteorology, although most of their attention has been given to climatology. ”

“ THE IMPORTANCE OF METEOROLOGY: ITS RELATIONS TO MAN.
We live in the laboratory of the earth’s atmosphere. The changes from hot to cold, wet to dry, clear to cloudy, or the reverse, profoundly affect us. We make and unmake our daily plans; we study or we enjoy vacations; we vary our amusements and our clothing according to these changes. The weather forecasts for the day in the newspaper are read even before the telegraphic despatches of important events. Sailors about to put to sea govern themselves according to the storm warnings of our Weather Bureau. ”

“ The study of the relations between temperature and vertical altitudes is a matter of great importance in meteorology, and it has been prosecuted diligently during the last quarter of a century in various parts of the United States, Canada, Europe, South America and Africa. ”

“ In other words, when definite conditions of weather have thoroughly established themselves, it is only with great difficulty that the courses of the atmospheric currents are changed.”
To bring within the limits of a popular pamphlet a notice of the various phenomena classed under the head of Meteorology, it has been necessary to exercise the utmost brevity. ”

“ The study of the atmosphere and its phenomena. Efforts are being made by every civilized nation to apply to the benefit of mankind the knowledge we possess of meteorology, especially to foretell the winds and weather from day to day and the general character of the seasons from season to season. About fifty official governmental weather bureaus receive reports from their stations by telegraph daily, compile weather maps, issue forecasts, and publish weekly, monthly, or annual climatological summaries, together with frequent special meteorological memoirs. ”

“ By the aid of its newest instrument, meteorology, it lets us see how incident solar energy, raising clouds and causing rainfall, with its attendant phenomena of drainage and rivers, has carved and denuded the upheaved masses into infinite variety of hill and valley. ”

“ Inasmuch as the science of meteorology is chiefly a study of the air, a mixture of gases differing in their specific properties, a clear exposition of these general properties is necessary to an understanding thereof—more especially to the solving of the problems of weather, climate, and habitability. ”

“ These governmental bureaus usually pursue both Climatology and theoretical meteorology in addition to their daily practical work of telegraphy, forecasting, and publication of charts. Although, of course, in most cases, the so-called practical work absorbs the greater part of the labour and the funds, yet everywhere it is recognized that research and the development of a correct theory of the motions of the atmosphere are essential to any important progress in the art of forecasting. ”

“ The instruments that respond most nearly to the general needs of meteorology are the various forms of meteorographs devised by Wild for use at St Petersburg, by Sprung and Fuess for use at Hamburg and Berlin, and by Marvin for Washington. The photographic systems for pressure and temperature introduced many years ago at stations in Great Britain and the British colonies are not quite adequate to present needs. ”

“ Small things must not be overlooked, for great discoveries are sometimes at a man’s very door. Dr. Aitken has shown us this in many of his discoveries which have revolutionised a branch of meteorology. Prudence, patience, observing power, and perseverance in scientific research will do much to bring about unexpected results, and not more so in any science [Pg 13] than in accounting for weather-lore on a rational basis, which it is in the power of all my readers to further. ”

“ While these practical results are exceedingly worthy of attention, and inspire us with the hope that the time shall come when perfected instruments, improved methods, and increased knowledge, shall enable the meteorologist to predict with the utmost certainty every atmospheric disturbance, they yet fall into the shade when compared with the magnificent and luminous conceptions which meteorology has added to cosmological science. ”

“ It must occur to everyone to adopt the intermediate view that, on the one hand, the local vertical circulation, with its clouds, rain, hail and snow, and evolution of latent heat, and, on the other hand the waves and whirls in the general circulation, mutually contribute toward our storms and fair weather. It only remains to allot to each its proper importance in any special case.
Undoubtedly aerial billows, and the clouds that must frequently accompany them, exist everywhere in the earth’s atmosphere. ”

“ Researches are now being carried on which tend to show that the meteorology of the two hemispheres is more interdependent than was hitherto believed, so that a meteorological disturbance in one part of the world makes its presence felt, more or less remotely perhaps, all over the world. ”

“ Meteorology has advanced very far beyond its original limits. Spherical vapor and atmospheric space give but a faint idea of its range. We find it a leading science in Physics, and having intimate relations with heat, light, electricity, magnetism, winds, water, vegetation, geological changes, optical effects, pneumatics, geography,--and with climate, controlling the pursuits and affecting the character of the human race. ”

“ It should need no insisting on that the data required by meteorologists are not sufficiently supplied by the readings of instruments placed on or near the ground, or by the set of the wind as determined by a vane planted on the top of a pole or roof of a building. The chief factors in our meteorology are rather those broader and deeper conditions which obtain in higher regions necessarily beyond our ken, until those regions are duly and diligently explored. ”

“ All weather-wisdom depends upon the principle that Nature never gives false signals, that her laws are invariably true; we cannot interpret them, or we interpret them wrongly. Averages, statistics, observation, instruments, &c., are all helps to a surer interpretation. In proportion as our knowledge of Nature increases, and our instruments are better understood, so will meteorology extend her sway. Thus it has been proposed to give storm warnings to ships in the offing by means of coloured lights. ”

“ The observer generally confines his attention to that portion of the sky within sixty degrees of the zenith, and ignores the lower zone, since the clouds that are found therein are often at so great a distance from him that their record is not supposed to belong to his locality. As the cloudiness—or its reciprocal, the sunshine—is supposed to be the most important item in agricultural climatology, and is certainly very important for dynamic meteorology, it is usually considered desirable to obtain more complete records than are given by only one or two specified hours of observation. ”

“ To further the application of meteorology to aviation, shipping, agriculture, and other human activities; and (e) To encourage research and training in meteorology and to assist in coordinating the international aspects of such research and training. ”

“ Few sciences perhaps will yield so important practical results as meteorology is likely to do at some future date—a fact, or rather an already partly realised expectation, which has won general recognition, as is shown by the large sums which in all civilised countries have been set apart for establishing meteorological offices and for encouraging meteorological research. ”

“ Study carefully, as in the previous problems, the relation of the different types of temperature distribution in the atmosphere to the weather conditions as shown on the daily weather maps.
Observations made in different parts of the world, on mountains and in balloons, have shown that on the average the temperature decreases from the earth’s surface upwards at the rate of about 1° in 300 feet of ascent. The rate of vertical decrease of temperature is known in meteorology as the vertical temperature gradient. ”

“ Does there seem to you to be any definite system, of any kind, in our changes of temperature? In what ways are people in general affected by hot weather? By cold weather? What difference does a very hot or a very cold day make in your own case?
Wind Direction and Velocity.—Wind is an important meteorological element because it has many close relations to human life. It affects very markedly our bodily sensations of heat or cold. A cold, calm day is pleasanter than a cold, windy day. On the other hand, a hot, calm day is usually much more uncomfortable than a hot, windy day. ”

“ At night the direction of the wind is reversed, that is, it blows from the land to the sea. Why? Because the land during the day retains its heat, while the water diffuses it. What is the result? The air on the land expands, becomes light. The air over the water being cool, it does not expand, and the result is that it presses toward the land. At night the land loses its heat more rapidly than the water, so that it is not long before the land is cooler than the water, and when this happens, the air over the land, which has become cooler, presses seaward. ”