El Nino / La Nina for the Navy

How might El Niño affect the Navy?

Much can be found in the way of El Niño and its impacts, both ecologically and economically, but there is little to be found relating this powerful phenomenon and the way it indirectly affects the operations of our Navy.

Nonetheless, the accompanying sea temperatures, wave heights, and atmospheric changes are certain to play a role in these operations.

El Niño's potential effects on the surface Navy

  ship at sea   several ships at sea

The most obvious of these changes that we see here on the continental United States are abnormal precipitation patterns during an El Niño event. The same can be said over the entire breadth of the Pacific Ocean. One fantastic depiction of how the El Niño has altered the frequencies and locations of Pacific tropical storms is depicted by the University of Washington, in the charts below of storm tracks.

Thus far, the operational effect that El Niño has had on the Navy has been minimal, but the potential effect is great. The Navy's Pacific Meteorology and Oceanography Center and Meteorology Detachment, both in Pearl Harbor, Hawaii, must pay special note to this transitioning tropical storm pattern. Seen here are La Niña tropical cyclone tracks and El Niño tropical cyclone tracks

click to see map of tropical cyclone tracks for non-El Nino years               click for tropical cyclone tracks during El Nino events

produced by the center in Pearl Harbor. These slides depict the changes that can result from an El Niño event. The awareness of such changes better allows the center to inform ships at sea of the impending dangers to safe passage that such anomalies can create.

One major thing that the most recent El Niño phenomenon has affected is the potential strength and extent of Eastern Pacific tropical cyclones. The large warm water pool in the EASTPAC allows tropical cyclones to move into areas they normally would not (e.g. Hawaii, and most EASTPAC Navy transiting lanes).

The tropical cyclone season also seems to be extended due to El Niño. There have not been any "El Niño" tropical cyclones as of yet, but the Optimum Track Ship Routing (OTSR) and meteorological support for transiting ships in the EASTPAC is at a very high level.

The change in storm paths and frequencies is not isolated simply to the Pacific Basin as you probably know. Both the Atlantic and Pacific basins show variations in storm frequencies and paths in relation to the El Nino phenomenon. The Atlantic experiences fewer hurricanes during El Niño years than are normally (right map) experienced in La Niña years.

El Niño's potential effects on the Naval Submarine force

animation of a submarine

view inside a submarine sonar room Sonar room onboard a Navy submarine                

Another effect that El Niño has is that the shifted warm pool into the EASTPAC affects ocean thermal fronts and eddies, which changes the Undersea Warfare (USW) tactics in the EASTPAC. The data on this effect is, no doubt, classified. However, submarines, whose "eyes" are located in the sonar room, are affected by the altered water temperatures and perhaps changed salinity properties as well. With sound traveling faster in warmer water than colder water and refraction increasing with increased temperature, the Undersea Warfare picture for the Navy is altered.

El Niño's potential effects on Naval Aviation

helocopter image       landing on a carrier       F14 over the Alps

The potential effect on aircraft operations could be great during an El Niño event. Because the Pacific transiting lanes are affected by altered storm tracks, search and rescue operations along these routes are made increasingly dangerous. Sonar detection by sonobuoys dropped by aircraft could be made more difficult by the background noise of storms, or altered by the changed water temperatures and salinities. In addition, El Niño-induced storms could potentially wreak havoc on aircraft attempting to land at sea. As seen in the image to the right above, an F-18 attempts to land on the rolling deck of an aircraft carrier.