Editing Climatology (section)

=== Climate variability ===
There are different types of variability: recurring patterns of temperature or other climate variables. They are quantified with different indices. Much in the way the [[Dow Jones Industrial Average]], which is based on the stock prices of 30 companies, is used to represent the fluctuations of stock prices in general, climate indices are used to represent the essential elements of climate. Climate indices are generally devised with the twin objectives of simplicity and completeness, and each index typically represents the status and timing of the climate factor it represents. By their very nature, indices are simple, and combine many details into a generalized, overall description of the atmosphere or ocean which can be used to characterize the factors which effect the global climate system.

[[El Niño–Southern Oscillation]] (ENSO) is a coupled ocean-atmosphere phenomenon in the Pacific Ocean responsible for much of the global variability of temperature,{{Sfn|Rohli|Vega|2018|p=54}} and has a cycle between two and seven years.<ref>{{cite web|url=http://www.cpc.noaa.gov/products/analysis_monitoring/ensostuff/ensofaq.shtml#HOWOFTEN|title=ENSO FAQ: How often do El Niño and La Niña typically occur?|access-date=26 July 2009|date=19 December 2005|author=Climate Prediction Center|publisher=[[National Centers for Environmental Prediction]]|archive-url=https://web.archive.org/web/20090827143632/http://www.cpc.noaa.gov/products/analysis_monitoring/ensostuff/ensofaq.shtml#HOWOFTEN|archive-date=27 August 2009|url-status=dead|author-link=Climate Prediction Center}}</ref> The [[North Atlantic oscillation]] is a mode of variability that is mainly contained to the lower atmosphere, the [[troposphere]]. The layer of atmosphere above, the [[stratosphere]] is also capable of creating its own variability, most importantly the [[Madden–Julian oscillation]] (MJO), which has a cycle of approximately 30 to 60 days. The [[Interdecadal Pacific oscillation]] can create changes in the Pacific Ocean and lower atmosphere on decadal time scales.