What natural phenomenon is referred to as La Niña?

La Niña refers to the periodic cooling of the ocean surface temperatures in the central and eastern tropical Pacific Ocean. This phenomenon is characterized by a complex interaction between the ocean and the atmosphere, which can lead to significant climatic effects around the globe. During La Niña events, stronger-than-normal trade winds push warmer water towards the western Pacific, resulting in cooler surface waters in the eastern Pacific. This cooling can influence weather patterns, leading to increased rainfall in some regions and drier conditions in others, impacting agriculture, ecosystems, and weather systems worldwide.

Understanding La Niña is critical in the context of global climate variability and its implications for weather events such as hurricanes, droughts, and floods. The other options describe different phenomena; for instance, warming of the Pacific Ocean corresponds to El Niño, while temperature changes in the Gulf of Mexico do not specifically define La Niña, and a cyclone is a distinct meteorological system unrelated to the temperature variations in the Pacific Ocean.