Climatology has evolved along with our ability to observe and measure the system’s elements including basic temperature and precipitation, cloud types, atmospheric humidity, wind speed and velocity, barometric pressure, soil moisture, and many more. Presently, scientists monitor weather and climate using a combination of instruments that make surface-based and upper-air (i.e., radiosondes or rawindsones) observations at various locations, and satellites that monitor wide geographic areas. Many also study past climatic conditions at times before the instrumental records (> ~ 1ka) using proxy records, or non-atmospheric indicators of atmospheric conditions such as tree rings, pollen, ice cores, and rock types (Robinson and Henderson-Sellers, 1999; Ruddiman, 2001).