Arab weather - The latest statistical forecasts for Arab weather still indicate an expected return to the La Niña phenomenon in the coming months again, God willing, and the weather forecast cadre in Arab weather in this report shows the extent of the impact of this phenomenon on world weather and the weather of the Arab world in particular.
The La Niña phenomenon is initially defined as a decrease in surface water temperatures in the tropical region of the Pacific Ocean from its general average by more than 0.5°C and over a period of time that exceeds 3 consecutive months.
The trade winds blow from east to west in the equatorial region of the Pacific Ocean as a result of the Earth’s rotation around itself, and from here begins the story of La Niña. The moist forms a system of low atmospheric pressure, then the air travels again along the upper part of the troposphere towards the eastern Pacific Ocean, forming a ring, then this cold air converges up and down along the eastern coast of the Pacific Ocean forming a region of high pressure, and then the wind moves From the high to the low level, the trade cycle is completed.
The end result is warmer surface waters in the west and cooler surface waters in the east. The Australian continent is saddled with intensified rainfall as a result of the retreat of warm waters in the western Pacific Ocean, in contrast to weaker rains in the coasts of Peru and South America, which suffer from cold waters adjacent to it.
The effect of the La Niña phenomenon is not limited to the vertical movement of air at the equator, but its effect is evident on the horizontal movement, where the rising air from the equatorial region of the Pacific Ocean branches away from the equator towards higher latitudes in the north and south, moving the hot tropical air towards the tropics Cancer and Capricorn descend towards the surface of the earth and return again to the equator and this is called the Hadley rotation .
The subtropical jet stream is formed as a result of the confluence of the upper winds from the Hadley cycle with the Ferrel cycle, which means that the La Niña phenomenon indirectly affects the subtropical jet stream and the atmospheric heights that arise at latitudes close to 30 degrees north, such as the subtropical high. The phenomenon of La Niña towards the Indian Ocean, as it indirectly leads to a decrease in the surface water temperature in the western part of the Indian Ocean and the Arabian Sea, which leads to a decrease in the amount of water vapor rushing towards the atmosphere of the Arabian Peninsula after God’s will.
The La Niña phenomenon is primarily a statistical phenomenon, that is, it depends on temperature anomalies during a certain time period (since the beginning of climatic records, i.e. since 1960 AD), and the La Niña phenomenon is statistically linked to rainy seasons less than the average in the Arab Mashreq, in complete contrast in the Maghreb regions with an increase Rainfall, lower temperatures than normal, and increased chances of floods and torrential rains in the Maghreb regions.
“Misconceptions about El Nino” is the title of a study published by the International Agency NOAA, expressing that El Nino and its counterpart La Nina are an atmospheric variable that contributes among dozens of other variables in the weather, perhaps the most prominent of which is the surface temperature of the waters of the northern half of the Atlantic Ocean ( AMO ) and the movement of occasional air currents in the stratum Stratosphere ( QBO ), and many other atmospheric factors, meaning that the weather is not exclusive and the result of a particular weather phenomenon.