Accumulated Cyclone Energy (ACE)-Used to measure energy used by a tropical cyclone in its lifetime. The stronger and longer lived a tropical cyclone is, the higher the ACE is. In addition, higher the ACE, the more active the season will be.
Arctic Oscillation (AO)-An atmospheric pattern that is characterized by sea level pressure anomalies. A positive AO is
Atlantic Multidecadal Oscillation (AMO)-Sea surface temperature variability in the North Atlantic Ocean. Positive AMO is warmer, while negative AMO is cooler.
El Nino Southern Oscillation (ENSO)-Climatic pattern that happens in equatorial/tropical Pacific Ocean. A warm or positive ENSO is El Nino, while cool or negative ENSO is La Nina.
Indian Ocean Dipole (IOD)-Sea surface temperature variability in the Indian Ocean. Characterized by warm and cool phase in different parts of the Indian Ocean.
Madden–Julian Oscillation (MJO)-A traveling atmospheric pattern that happens in 30 to 90 day intervals. Moves eastward from Indian, Pacific, and Atlantic Ocean. MJO phases are enhanced rainfall and dryness.
Multivariate ENSO Index (MEI)-El Nino Index based on sea surface temperature, sea-level pressure, wind patterns, cloud cover, and surface temperature.
North Atlantic Oscillation (NAO)-Climatic pattern in the North Atlantic Ocean, which is characterized by pressure differences with the Azores High and Icelandic Low. It is part of the Arctic Oscillation.
Pacific Decadal Oscillation (PDO)-A climatic pattern that occurs in the Pacific and shifts every 20 to 30 years. Positive is warm, while negative is cooler.
Pacific-North American (PNA)-Atmospheric teleconnection pattern that is centered over Alaska.
Quasi-Biennial Oscillation (QBO)-An oscillation of the equatorial wind zone between easterlies (negative) and westerlies (positive) in the tropical stratosphere. First noticed in 1883 after the Krakatoa volcanic eruption.
Southern Oscillation Index (SOI)-Atmospheric component of ENSO.