Washington, D.C. is enduring its second major snowstorm in less than a week and the third this winter season. Experts say the oceanic disturbance known as El Niño is to blame for severe weather here and around the world in recent months.

Every three to seven years or so, heat buildup in the tropical Pacific Ocean reaches a critical point, says Kevin Trenberth at the U.S. National Center for Atmospheric Research.

"In some sense," Trenberth says, "the ocean says, 'I can't stand it anymore. I'm going to have an El Niño.'"

And when it does, look out.

The warmer Pacific Ocean pours heat and moisture into the atmosphere, disturbing the usual airflow patterns and messing up weather around the world. Although the 1997-98 El Niño event was stronger, Trenberth says this current one is the strongest in a decade.

"It's still probably not in the 'major' category," he says, "but it's having some substantial influences around the world."




Storms, droughts linked

Southeast Asia felt El Niño's influence during last year's typhoon season. A series of devastating storms hit the region, killing thousands and causing massive flooding and landslides. On the other hand, dry conditions are predicted for Indonesia, raising the risk of forest fires. And farther west, late monsoon rains caused crop failures in parts of India. That has helped drive up food prices.

Although it's harder to say to what degree El Niño is to blame for India's late monsoon, Trenberth says, "It certainly doesn't help. Let me put it that way."

Some good news

But El Niño isn't all bad news. Drought-stricken California is getting some much-needed rain. And parts of Africa could benefit as well.

"The drought that's currently going on in Kenya could be alleviated by the conditions that develop in the later stages," Trenberth says. El Niño conditions are expected to continue for at least the next couple months. After that, the cycle goes into transition mode. "That's where the predictability, so to speak, is actually probably less than at any other time."

As another snowstorm blankets Washington, D.C., the prospect of more unpredictable weather is hardly a comforting thought.

華盛頓特區(qū)是持久的，在不到一個星期，第三這個冬天的第二大暴雪。專家說，海洋干擾厄爾尼諾知道的是歸咎于惡劣天氣在最近幾個月在這里和世界各地。

每3至7年左右，在熱帶太平洋的熱量不斷積聚達到一個臨界點，凱文說，在美國國家大氣研究中心Trenberth。

“從某種意義上說，”Trenberth說，“海洋說，'我不能忍受了。我將有一個厄爾尼諾現(xiàn)象。”

當它好看的。

溫暖的太平洋大氣倒入熱量和水分，擾亂正常空氣流動模式和搞亂世界各地的天氣。雖然1997-98年厄爾尼諾事件是強大，Trenberth目前一說，這是10年最強的。

“它仍然可能是在'大'類別沒有，”他說，“但它擁有世界各地的一些實質(zhì)性的影響。”

風暴，干旱鏈接

東南亞認為在去年的臺風季節(jié)厄爾尼諾現(xiàn)象的影響。阿一系列災(zāi)難性風暴襲擊該地區(qū)，造成數(shù)千，造成巨大的洪水和泥石流災(zāi)害。另一方面，干燥天氣，預(yù)計印尼，提高森林火災(zāi)的風險。遠西部地區(qū)，季風降雨造成后期在印度部分地區(qū)作物歉收。這有助于食品價格上漲的驅(qū)動器。

雖然它很難說到什么程度厄爾尼諾現(xiàn)象歸咎于印度季風后期，Trenberth說：“這當然不是幫助。讓我這樣說的。”

一些好消息

但是，厄爾尼諾現(xiàn)象是不是所有的壞消息。遭受旱災(zāi)的加州是得到一些急需的降雨。和非洲部分地區(qū)也可以受益。

“干旱是對目前在肯尼亞可由緩解的條件是，在后來的發(fā)展階段之后，”Trenberth說。厄爾尼諾條件，預(yù)計將持續(xù)至少在未來幾個月內(nèi)。在此之后，周期現(xiàn)為過渡模式。 “這就是可預(yù)測性，可以這么說，實際上，大概不到任何時候。”

正如另一位雪災(zāi)毛毯，華盛頓特區(qū)，更不可預(yù)測的天氣前景并不舒服的。