Development of the Heat Budget Concept

Abstract

T_Teat budgeting has come into prominence in geography and climatology only since World War II. Earlier, it appeared chiefly in the superficial diagrams of the planetary heat balance re printed in the opening section of textbooks, which usually show the budget of energy at the surface of the earth incompletely if at all. Casting the accounts of energy, its income, storage, and outgo at the variegated surface of the earth is, however, an effective tool. It is a means of evaluating many geographic processes and their inter actions, analyzing their variations in time, and depicting their dis tributions over spatial domains of different sizes. The delay in the acceptance of such a useful set of relations about the earth's surface is puzzling. Why did this technique come so late? The energy budget concept is just as valuable in geophysics and geography as in such completely artificial systems as heat ex changers and engines, and in such natural systems as cloud droplets. Its connections with phenomena in the water budget are so close that the two often are investigated together. It provides a powerful means of explaining many features observed in the local air and the upper layers of the soil, and thus is employed in meteorology, botany, and soil science, as well as in the derivative fields of hydrology, agronomy, and forestry. It offers a quantitative expression of the linkages between substrate and local air that account for so many characteristics of local climate, and provides explanatory methods for geography as the study of the earth's surface. The development of the energy budget can be traced from its early formulations, conceived on a global scale without recognition