What unusual pattern occurs during EI Niño

It appears you’re referring to **El Niño**, a significant climate phenomenon that forms part of the larger El Niño-Southern Oscillation (ENSO) cycle. During an El Niño event, several unusual and impactful patterns emerge, primarily driven by changes in oceanic and atmospheric conditions in the Pacific Ocean. Here are the key unusual patterns associated with El Niño: 1. **Warming of the Central and Eastern Pacific Ocean:** - **Sea Surface Temperatures (SSTs):** Typically, the western Pacific near Indonesia is warmer, while the eastern Pacific near South America is cooler due to upwelling of cold, nutrient-rich waters. During El Niño, SSTs in the central and eastern equatorial Pacific become significantly warmer than average. 2. **Weakening or Reversal of Trade Winds:** - **Trade Winds:** Under normal conditions, trade winds blow westward across the Pacific, helping to pile up warm water in the western Pacific. El Niño weakens these winds, and in some cases, they may even reverse direction. This allows the warm water to spread eastward toward the coast of South America. 3. **Altered Atmospheric Circulation:** - **Atmospheric Patterns:** The shift in warm water distribution disrupts typical atmospheric circulation patterns, including the Walker Circulation. This can lead to changes in wind patterns, cloud cover, and precipitation across various regions. 4. **Changes in Precipitation and Weather Patterns:** - **Increased Rainfall:** Regions like the western coast of South America may experience heavy rainfall and flooding. - **Drought Conditions:** Conversely, areas such as Australia, Southeast Asia, and parts of Africa might suffer from prolonged droughts. - **Altered Storm Tracks:** The paths of storms and tropical systems can shift, leading to unusual weather events in regions that typically don’t experience them. 5. **Suppressed Upwelling and Impacts on Marine Life:** - **Upwelling Reduction:** Normally, upwelling brings nutrient-rich cold water to the surface in the eastern Pacific, supporting diverse marine ecosystems. El Niño suppresses this upwelling, which can lead to declines in fish populations and affect fisheries. 6. **Global Climate Impacts:** - **Temperature Extremes:** El Niño can contribute to global temperature increases, often making years with strong El Niño events among the warmest on record. - **Extreme Weather Events:** The disruption of normal weather patterns can lead to a higher incidence of extreme weather events globally, such as heatwaves, hurricanes, and heavy rainfall. **Summary:** During El Niño, the central and eastern Pacific Ocean experiences unusually warm sea surface temperatures due to weakened trade winds. This shift disrupts normal atmospheric circulation, leading to altered precipitation patterns, suppressed upwelling, and various global weather anomalies. These changes can have profound impacts on ecosystems, economies, and weather systems around the world. If you meant a different phenomenon by "EI Niño," please provide additional details, and I’d be happy to assist further!