THE EFFECT OF LAND AND SEA (1) How Oceaps and Continents Influence Temperature.—The simple arrangement of the climatic belts considered in the previous chapter and shown in Fig. 70 must now be modified to show the „ influences of (a) the distribution of land and sea, and (b) mountains and plains.
The land and the sea differ greatly in climate. This, as we have seen, is because land becomes hot under the sun's rays much more rapidly than does water, and likewise cools much more rapidly. This is evident to anyone who goes to the seashore either in summer or winter. In June a dweller in Minneapolis may leave his home at a temperature of 90° for a trip to Europe. Three days later in the same latitude on the Atlantic he may want his overcoat in a noon temperature of only 55°. The ocean water still retains something of the cold of winter.
It is not necessary to go so far, however, in order to note the con trast between land and sea. Often the summer air is cool and bracing close to the seashore, while ten miles inland it is hot and depressing. On the coast of central California at places like Monterey people jokingly say that in summer they must go into the interior to get warm. The ocean is so cool and west winds blow from it so steadily that the thermometer stays between and even when there are temperatures of over one or two hundred miles away in the great interior valley, where the land has yielded to the influence of the hot summer sun.
In the winter the contrast is the other way. A boy from central New York, for example, may leave his companions coasting on deep snow in January. At Boston in the same latitude, he may find bare ground and not even any skating. This is not because Boston has less precipitation than central New York, but because it lies on the seacoast and in winter is kept at a higher average temperature than the interior by occasional winds from the ocean.
Since the lands in summer become warmer than the oceans and in winter colder, the change from one season to the other mustbe — greater on the continents than on the oceans. This is illustrated by a comparison of Figs. 71 and 72, which show average temperatures in January and July.
Marine versus Continental Climates.—(a) The Uniform Marine Climate of the Lofoten Islands.—Let us compare an extreme marine climate with an extreme continental climate in the same lati tude. The southern Lofoten Islands off the coast of Norway, and
Verkhoyansk in Siberia, probably furnish the greatest contrast to be found anywhere between places lying at equal distances from the equator. Both are within the Arctic Circle. Yet in winter the winds blowing from the ocean prevent the Lofoten Islands from suf fering the usual Arctic severity of such latitudes. Grass remains green and cattle are pastured out-of-doors all the year. In summer, however, although the weather is milder than in winter, the tempera ture of the ocean is so nearly the same as in winter that the islandS are raw and chilly. So cool is the air that practically no trees and crops will grow, and the people wear the same thick, warm woolen clothing summer and winter alike. The great characteristic of the marine climate of the Lofotens is its uniformity.
(b) The Extreme Range of the Continental Climate at Verkhoyansk.
—Verkhoyansk is so different from the Lofoten Islands that one can scarcely believe that both places are in the same latitude and no farther apart than Portland, Maine, and Portland, Oregon. At the Siberian town the range from the average January temperature to the average of July is F., while in the Lofotens it is only At Verkhoyansk the temperature has been known to fall to below zero, and almost every year it goes down to —70 or — In fact the average for the whole month of January is about — It is so cold that a steel skate, so it is said, will not "take hold" of the over-hardened ice, but slips on the surface.
Strange as it may seem, the summer at Verkhoyansk is warmer than in the islands off the Norwegian coast. This, of course, is because the land of the continental interior yields quickly to the summer sun. The average temperature in July is or as high as the highest ever known in the Lofotens, where the July average is only Temperatures as high as have been recorded at Verkhoy ansk, while to is common during the long days of summer. Hence some trees grow in spite of the intense cold, and crops can be raised, although none will grow on the Norwegian islands. To be sure, the ground never really thaws. If. a man digs down a foot or so in his vegetable garden in July or August he comes to frozen soil, for only a thin layer on the surface ever melts.