Sandstrom, Johan Wilhelm
Johan Wilhelm Sandstrom (1874-1947), a German oceanographer, first described the fundamental mechanisms of the energy transfers that drive ocean circulation. He modeled oceanic circulation as a heat engine driven by gradients in temperature, pressure, and volume. Sandstrom's Theorem (1916) states that a closed steady circulation can only be maintained in oceans if the heat source is situated at a lower level than the cold source. Sandstrom's work would form the basis for understanding the role of oceans in global climate change.