On the Motion of Air near the Earth's Surface as Planetary Winds

Abstract

If the temperature gradient exists on the earth's surface, the upper currents tend to move along the isotherms on the earth's surface. The difference in temperature would cause the barometric gradient in the upper strata, which would hold the air away along isobars. The large temperature gradient would cause the barometric gradient in the upper strata still greater, making the wind still more vigorous. From this stand point, it is concluded that over the extratropical regions the velocities of upper currents are high and much greater in winter than in summer.
Next the main featu_??_es of the prevailing westerly winds over the extra-tropical belts and the mild easterly winds over the equatorial region are fully deduced.
The tropical belts of high pressure, located at 30°N or S latitude, are the so-called horse latitudes. There the wind is light and variable and the velocity small. The belts of highest pressure migrate toward the equator as the height increases, and are located at 15° N or S latitude on the upper limit of the troposphere.