The NASA Earth System Science Program in 21st Century

Abstract

The Earth is a dynamic system of land, oceans, and atmosphere that has evolved as a result of the complex biological, chemical and physical processes. These processes are interconnected by an intricate and fragile web that helps modulate such things as weather, droughts and floods and can ultimately have profound impacts on global food production, natural resource management, commerce and the global economy. The recently experienced 1997–98 El Nino cycle illustrates this complex interaction that began when the normal state of the Pacific ocean was perturbed by a weakening of the westerly trade winds; a state that is necessary to maintain a “pool” of warm water within the western tropical Pacific. The weakening of trade winds allowed warm water to flow eastward along the equator to coastal Peru. The eastward-spreading water brought with it the associated tropical rainfall. As the warm pool reached the coast of Peru, it spread to the north and south progressively cutting off the nutrient-rich upwelling along the Peruvian coast, and causing a collapse of the fishery and impacting the seabird population. As the heat from the warm pool escaped into the atmosphere it impacted global atmospheric circulation including the global jet streams.