What is the Lamina phenomenon?
La Niña (Spanish: La Niña), also known as the Anti-El Niño phenomenon, is a phenomenon opposite to El Niño, that is, the "cooling phase of the Eastern Pacific"; therefore, in Spanish it is El Niño is represented by the feminine noun La Niña.
La Niña refers to a large-scale cooling of ocean surface temperatures in the central and eastern equatorial Pacific, accompanied by changes in tropical atmospheric circulation (i.e., wind, pressure, and rainfall). Its effects on weather and climate are generally opposite to those of El Niño, the warm phase of the El Niño Southern Oscillation (ENSO).
“El Niño and La Niña are the main natural drivers of Earth’s climate system. But all current naturally occurring climate events occur against the backdrop of human-induced climate change, which exacerbates extreme weather , affecting the water cycle," said WMO Secretary-General Professor Petteri Taalas.
"La Niña typically has a cooling effect on global temperatures, but the heat trapped in the atmosphere by greenhouse gases is enough to offset this effect. As a result, 2020 will remain one of the warmest years on record , 2016-2020 is expected to be the warmest five years on record," Professor Taalas said. "The current La Niña year is even warmer than previous years with strong El Niño conditions."
WMO's new ENSO latest bulletin points out that tropical Pacific sea surface temperatures are likely (90%) to remain at La Niña levels and may persist into the first quarter of 2021 (55%). For more than a year prior, ENSO conditions were neutral (i.e., neither El Niño nor La Niña). This latest bulletin is based on forecasts from the WMO Global Long-term Forecast Production Center and expert analysis.
It is important to note that El Niño and La Niña are not the only factors driving global and regional climate patterns. Every La Niña or El Niño event is different, and their impact on regional climate can vary depending on the time of year and other factors. Therefore, decision makers should always monitor the latest seasonal forecasts for the most up-to-date information.
Impact
La Niña will cause global climate anomalies. Impacts include: making the southwestern United States and the west coast of South America abnormally dry, causing abnormally high rainfall in Southeast Asia such as Australia, Indonesia, Malaysia, and the Philippines, and causing abnormally high rainfall on the west and southeastern coast of Africa, Taiwan, Japan, and the Korean Peninsula. cold. In the northwest Pacific, the areas affected by tropical cyclones will be farther south and west than normal.
In addition, the subtropical high pressure will be stronger than normal, causing tropical cyclones to move west to west-northwest, and more tropical cyclones will appear in the Philippines and the South China Sea.
Interestingly, once La Niña occurs, hurricanes in the North Atlantic will also be extremely active.
For example: In the 2005 Atlantic hurricane season, there were four rare Category 5 hurricanes with the highest intensity, namely: Hurricane Emily, Hurricane Katrina, Hurricane Rita, Hurricane Vima, and Hurricane Mitch occurred earlier in the 1998 Atlantic hurricane season and caused heavy casualties and property damage in North and Central America. Among them, Hurricane Wilma was one of the strongest North Atlantic hurricanes on record.
The 2007 Atlantic hurricane season saw two Category 5 hurricanes with the same highest intensity: Hurricane Dean and Hurricane Phillis. The 2017 Atlantic hurricane season also had two highest intensity Category 5 hurricanes. Category 1 hurricanes Hurricane Irma and Hurricane Maria. In addition, the La Niña phenomenon sometimes leads to the occurrence of special situations where the number of typhoons in the northwest Pacific is relatively small but extremely powerful.