|Weather Prediction from Climatology|
G. H. TAYLOR (1). (1) Applied Climate Services, Corvallis, OR, U.S.A.
“Climate” and “weather” are related terms which describe patterns of temperature, precipitation, winds, humidity, and other characteristics of the atmosphere. They differ in time scale: “climate” represents atmospheric variables over long periods of time while “weather” describes short-term conditions in a given location or region.
It is well-known that climate varies in a quasi-cyclical manner according to a large number of periodicities. These include the so-called “Milankovich” cycles, which span 25,000-100,000 year periods and appear to coincide with ice ages, to much shorter cycles such as the 2.2-year Quasi-biennial Oscillation. Some of the cycles appear to be internally-based within earth’s ocean-atmosphere system, while others appear to be caused by external forcings (solar cycles, lunar tidal cycles).
In addition to improvements in the scope and accuracy of weather and climate data, some innovative and powerful software tools are becoming available for analytical purposes. Two examples are Regional L-Moments, used for spatial distributions of meteorological and hydrological variables; and PRISM (Parameter-elevation Relationships on Independent Slopes Model), the state-of-the-art tool for spatial distributions in areas with complex topography.