Climatology

Climatology is a branch of the atmospheric sciences that focuses on long-term (monthly and longer) patterns of weather and atmospheric circulation, in contrast with meteorology, which focuses on understanding and predicting short-term weather phenomena. While climate is often described as the “average weather” of a place, it is better considered as the aggregation of all the statistical properties of the atmosphere, including averages as well as measures of the expected variability and persistence over time of atmospheric elements such as temperature, rainfall, or humidity. In other words, climate includes not just averages, but is the total picture of the behavior of the atmosphere for the globe or a region. Climatologists seek to understand the mechanisms within the earth system that produce spatial patterns in climate, as well as the causes and implications of climate variations over time scales ranging from months to millennia and longer. In recent decades, a particularly important focus within climatology has been the question of whether and how human activities have caused changes to the climate system.

The climate system refers to all of the various boundary conditions that influence global and regional climates. Examples include the brightness of the sun, the configuration of the continents and ocean basins, the tilt of the earth on its axis, the shape of the earth's orbit, and the concentration of greenhouse gases in the atmosphere. These boundary conditions change at a variety of time scales, both naturally and due to human actions, and the interaction of these factors produces complex variations in climate patterns over space and at a wide range of time scales.

Within climatology, there are many subfields, each of which approaches the study of the climate from a unique perspective. One of these fields is paleoclimatology, which attempts to reconstruct past climate patterns from the evidence of ice cores, ocean sediments, tree rings, and other types of geophysical evidence that provides a look into how global and regional climates varied over millions of years. Paleoclimatology has a great deal of applicability to the field of anthropology, as climate variations likely played a role in the cultural development and movement of our human ancestors. In addition, paleoclimatology is useful in the modeling of future climate change, as past climates provide examples of the kinds of climate patterns that are possible given particular configurations of boundary conditions.

Climatologists are also interested in identifying and explaining the spatial patterns of climates across the earth's surface. Climate classification schemes use variables like temperature and rainfall to identify particular climate types (such as tropical, arid, or polar), which can then be explained in terms of climate-controlling factors like latitude, elevation, proximity to the coast, or atmospheric circulation patterns. One of the most famous of these classification systems is the Koeppen System, which divides climates into five general categories based on temperature and moisture patterns. Climate classification provides useful descriptions of large-scale climate conditions, which is valuable in understanding spatial patterns of biomes as well as the types of human activity (such as agriculture) that are likely in particular areas.

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