El Niño is part of a natural climate pattern that occurs roughly every two to seven years, bringing warmer-than-normal water to parts of the equatorial Pacific. The most recent very strong El Niño events, in 1997-98 and 2015-16, upended weather patterns. Impacts spanned the planet, from fires in Indonesia and the Amazon, to crop failures due to drought in southern Africa , to heavy rain and coastal flooding in Southern California. The current El Niño rivals these past heavyweights.
厄尔尼诺现象是自然气候模式的一部分，大约每两到七年发生一次，为赤道太平洋部分地区带来比正常情况更温暖的水温。最近一次非常强烈的厄尔尼诺事件（1997-98 年和 2015-16 年）颠覆了天气模式。影响遍及全球，从印度尼西亚和亚马逊的火灾，到南部非洲干旱造成的农作物歉收，再到南加州的暴雨和沿海洪水。当前的厄尔尼诺现象可与过去的这些重量级现象相媲美。
Every El Niño grows from a feedback loop between the atmosphere and the ocean. Trade winds normally keep warm water piled up in the western Pacific, where it stands higher than in the east. When those winds weaken, that warm water begins to pulse eastward, which further weakens and sometimes reverses the winds, allowing even more warm water to move east. The cycle intensifies as waters continue to warm and pile up in the central and eastern Pacific.
每次厄尔尼诺现象都是由大气和海洋之间的反馈循环产生的。信风通常会使西太平洋的温暖海水堆积起来，那里的水位高于东太平洋。当风减弱时，暖水开始向东流动，风进一步减弱，有时甚至逆转风，使更多的暖水向东移动。随着太平洋中部和东部海水持续变暖和堆积，这一循环加剧。
But each El Niño has its own character, shaped by where in the Pacific the warmth builds and how the atmosphere responds. “The search for the ‘typical’ El Niño is very elusive,” said Josh Willis, project scientist for sea level missions at NASA’s Jet Propulsion Laboratory (JPL). “They’re all different in terms of where they land and how their impacts play out.”
但每次厄尔尼诺现象都有其自己的特征，其特征取决于太平洋温暖的位置以及大气的反应。美国宇航局喷气推进实验室（JPL）海平面任务项目科学家乔什·威利斯（Josh Willis）表示：“寻找‘典型’厄尔尼诺现象非常难以捉摸。” “它们的着陆地点和影响如何发挥都是不同的。”
Altimetry satellites can track those differences by measuring the height of the sea surface. Because water expands as it warms, higher-than-normal sea levels in the central and eastern equatorial Pacific signal the buildup of heat associated with El Niño. The maps above depict sea surface height anomalies across the Pacific Ocean on October 13, 1997 (left), and on October 12, 2026 (right). Data are from the TOPEX/Poseidon satellite and the Sentinel-6 Michael Freilich satellite, respectively, and were processed by scientists at JPL.
测高卫星可以通过测量海面的高度来跟踪这些差异。由于水会随着变暖而膨胀，赤道中部和东部太平洋的海平面高于正常水平，标志着与厄尔尼诺现象相关的热量积聚。上面的地图描绘了 1997 年 10 月 13 日（左）和 2026 年 10 月 12 日（右）整个太平洋的海面高度异常。数据分别来自 TOPEX/Poseidon 卫星和 Sentinel-6 Michael Freilich 卫星，并由 JPL 的科学家处理。
Shades of red indicate where sea levels were higher than average. Normal sea level conditions appear white, and lower areas are blue. Signals related to seasonal cycles and long-term trends have been removed to highlight sea level anomalies associated with El Niño and other short-term natural phenomena.
红色阴影表示海平面高于平均水平的地方。正常海平面条件显示为白色，较低区域显示为蓝色。与季节周期和长期趋势相关的信号已被删除，以突出与厄尔尼诺现象和其他短期自然现象相关的海平面异常。
“What’s unique about altimetry is that we have a 35-year record from nearly identical satellites flying almost the same ground track, with each mission overlapping the next,” Willis said. “That lets us look back in time and compare this El Niño to what happened in 1997. And right now, this one is on track to be even bigger.”
威利斯说：“高度测量的独特之处在于，我们拥有 35 年的记录，几乎相同的卫星在几乎相同的地面轨道上飞行，每次任务都与下一个任务重叠。” “这让我们回顾过去，将这次厄尔尼诺现象与 1997 年发生的情况进行比较。而现在，这次厄尔尼诺现象的规模可能会更大。”
Compared with the 1997-98 event, El Niño in 2026 came on much more suddenly. But as of October, the two events appear similar in character—the tilt of sea level (low in the west and high in the east) and high, warm water extending all the way to South America—so Willis thinks the impacts could be similar as well. In 1997-98, that meant, for instance, lots of rain in California and across the southern tier of the U.S.
与1997-98年相比，2026年的厄尔尼诺现象来得突然得多。但截至 10 月，这两个事件在性质上似乎很相似——海平面倾斜（西部低，东部高）和高而温暖的海水一直延伸到南美洲——因此威利斯认为影响也可能相似。例如，1997-98 年，这意味着加利福尼亚州和美国南部地区会出现大量降雨。
The 2015-16 El Niño was another heavy hitter but differed in its character. Sea surface height anomalies on October 12, 2015, based on altimetry data from the Jason-2 satellite, are shown above in context with maps from around the same time in 1997 and 2026. In 2015, the exceptionally warm, high water along the equator didn’t push up against South America to the extent it did in the other years. Rainfall impacts that winter concentrated more over Central America and the southeastern U.S., with significant flooding in Mexico.
2015-16 年的厄尔尼诺现象是另一个重磅事件，但其特征有所不同。根据 Jason-2 卫星的测高数据，2015 年 10 月 12 日的海面高度异常如上图所示，并结合 1997 年和 2026 年大约同一时间的地图。2015 年，赤道沿线异常温暖的高水位没有像其他年份那样对南美洲产生推力。冬季的降雨影响主要集中在中美洲和美国东南部，墨西哥发生严重洪水。
NOAA’s El Niño outlook on October 8, 2026, called for an 83 percent chance of a strong-to-very strong El Niño through the first three months of 2027. But exactly how the impacts will play out in winter 2026-27 and beyond remains to be seen. Willis noted that El Niño’s influence propagates through a chaotic atmosphere, and the signal can get muddled as it extends beyond the tropics. “There’s always a bit of a dice roll here,” Willis said. “Just because this El Niño looks like 1997 doesn’t mean it will be exactly the same—it’s just our best guess at the moment.”
美国国家海洋和大气管理局 (NOAA) 2026 年 10 月 8 日的厄尔尼诺现象展望预计，2027 年前三个月出现强至极强厄尔尼诺现象的可能性为 83%。但其影响在 2026-27 年冬季及以后将如何发挥，仍有待观察。威利斯指出，厄尔尼诺现象的影响通过混乱的大气层传播，当它延伸到热带地区之外时，信号可能会变得混乱。 “这里总是有一些掷骰子的事情，”威利斯说。 “仅仅因为这次厄尔尼诺现象看起来像 1997 年，并不意味着它会完全相同——这只是我们目前最好的猜测。”
NASA Earth Observatory maps by Lauren Dauphin, using NASA-SSH altimetry data provided by Josh Willis, Severine Fournier, and Kevin Marlis, NASA/JPL-Caltech. Story by Kathryn Hansen.
NASA 地球观测站地图由 Lauren Dauphin 绘制，使用了 NASA/JPL-Caltech 的 Josh Willis、Severine Fournier 和 Kevin Marlis 提供的 NASA-SSH 测高数据。凯瑟琳·汉森的故事。