The influence of natural climate variability on tropical cyclones

We present a review of the relationship of climate and tropical cyclones on various time scales, from intra- seasonal to decadal. The response of tropical cyclone activity to natural modes of variability, such as El Niño- Southern Oscillation (ENSO) and the Madden Julian Oscillation (MJO) in various regions of the world are discussed. Globally, ENSO and the MJO modulate TC activity.The nature of the modulation depends on the region considered. On a regional scale, other climate modes also affect TC activity. These modes of variability affecting only specific regions, such as the Atlantic Meridional Mode, will also be examined. Genesis location, track types and intensity of tropical cyclones are influenced by these modes of variability. Many of the relationships are well-documented empirically, but our understanding of the physics behind them remains rudimentary due to our incomplete understanding of how the large-scale environment influences TC formation and intensification in general.