据美国国家航空航天局称，澳大利亚毁灭性的丛林大火产生的烟雾预计将在全球范围内完成一个完整的循环，回到产生它的国家的天空。它还飞得很高，到达了平流层——地球大气层的第二大层。
到1月8日，烟雾已经到达南美洲，使得一些地区的天空变得朦胧，导致五颜六色的日出和日落。航天局说。
据英国广播公司报道，自去年9月以来，澳大利亚数百场大火烧毁了数百万公顷土地，造成至少28人死亡，约2000所房屋被毁，超过10亿只动物死亡。
科学家表示，破纪录的高温干燥条件正在为火势蔓延创造完美的环境。德国波茨坦气候影响研究所的斯特凡·拉姆斯托夫说，随着世界气候变化，这种情况在澳大利亚可能会变得更加普遍时间。
据美国国家航空航天局称，炎热和干燥也导致了“异常大量”的所谓积雨云(pyrCbs)事件的形成。这些雷暴是由火灾本身产生的。
“它们是由火山灰、烟雾和燃烧物质通过过热上升气流上升而触发的。当这些物质冷却时，云就形成了，表现得像传统的雷暴，但没有伴随的降水，”美国宇航局的一份声明写道。
虽然焦积雨云的形成相对常见，但气象学家迈克尔·弗洛姆(Michael Fromm)和美国海军研究实验室的同事在2019年12月的最后一周和2020年的第一周已经探测到20多场火灾引发的风暴。
“根据我们的测量，这是澳大利亚最极端的积雨云风暴爆发，”弗洛姆在一份声明中说。
PyrCbs可以帮助烟雾扩散到世界各地，使其到达平流层，平流层从大约6.2英里的高度(赤道以上)开始。澳大利亚上空的火山爆发事件将一些烟雾推入平流层，这些烟雾已经达到9至12英里的高度。
下面这张来自国际空间站的照片显示了2020年1月4日极端的火灾活动。
弗洛姆说:“将这种烟柱的高度与其他烟柱进行比较和排名还为时过早，因为像这样的烟柱在几周内会上升。”。
“也就是说，初步证据表明，目前的澳大利亚事件很可能会落在所有记录在案的羽流高度前五名之内。喷入平流层的烟雾总量似乎是近几十年来观察到的最大数量之一。”
一旦烟雾进入平流层，它会在那里停留几个月，从源头移动数千英里，影响全球大气状况。
新西兰距离澳大利亚东海岸1000多英里，受到火灾烟雾的影响尤为严重。美国国家航空航天局称，该国一些地区的空气质量很差，山顶上已经发现明显变黑的雪。
据英国广播公司报道，在当地，悉尼、墨尔本、堪培拉和阿德莱德等几个澳大利亚城市，由于吸烟，最近空气质量达到了危险水平，该国东部仍有100多起火灾在燃烧。
许多火灾仍有待控制。然而，消防队员周一宣布，他们终于控制住了澳大利亚最大的“巨型建筑”，这是这个火灾季节难得的好消息。
在三个月的时间里，悉尼西北方80多万公顷的森林被戈斯帕斯山大火烧毁。但是新南威尔士州的消防队员说，“遏制预测看起来很有希望”，在接下来的几天里，该地区急需的潮湿天气预报，法新社报道
SMOKE FROM AUSTRALIA FIRES HAS NOW REACHED THE STRATOSPHERE, NASA SAYS
Smoke from the devastating bushfires in Australia is expected to complete a full circuit around the world, arriving back in the skies over the country where it was produced, according to NASA. It has also traveled so high it has reached the stratosphere—the second major layer of Earth's atmosphere.
The smoke had reached South America by January 8, turning skies hazy in some regions, causing colorful sunrises and sunsets, the space agency said.
Since September last year, hundreds of fires have burned millions of hectares in Australia, leaving at least 28 people dead, destroying around 2,000 homes and killing more than one billion animals, the BBC reported.
Scientists say that record-breaking hot and dry conditions are creating the perfect environment for the fires to spread. These kinds of conditions are likely to become more common in Australia as the world's climate changes, Stefan Rahmstorf, from Germany's Potsdam Institute for Climate Impact Research, told Time.
According to NASA, the heat and dryness has also led to the formation of "an unusually large number" of so-called pyrocumulonimbus (pyrCbs) events. These are thunderstorms that are generated by the fires themselves.
"They are triggered by the uplift of ash, smoke, and burning material via super-heated updrafts. As these materials cool, clouds are formed that behave like traditional thunderstorms but without the accompanying precipitation," a NASA statement read.
While the formation of pyrocumulonimbus clouds is relatively common, meteorologist Michael Fromm and colleagues from the U.S. Naval Research Laboratory have detected more than 20 fire-induced storms in the last week of December 2019 and the first week of 2020.
"By our measures, this is the most extreme pyrocumulonimbus storm outbreak in Australia," Fromm said in a statement.
PyrCbs can help the smoke to spread around the world, by enabling it reach the stratosphere, which begins at around 6.2 miles in altitude (above the equator.) Some of the smoke pushed into the stratosphere by pyroCbs events above Australia has reached altitudes of between 9 and 12 miles.
The photograph below from the International Space Station shows extreme fire activity on January 4, 2020.
"It is premature to compare and rank the height of this plume with others because smoke plumes like this rise in altitude over the course of weeks," said Fromm.
"That said, preliminary evidence indicates that the current Australian event will probably fall within the top five of all the plumes ever documented in terms of height. And the overall volume of smoke injected into the stratosphere appears to be among the largest observed in recent decades."
Once the smoke is in the stratosphere, it can remain there for several months, travelling thousands of miles from its source and affecting atmospheric conditions globally.
New Zealand—which lies more than 1,000 miles away from Australia's east coast—is being particularly badly affected by the fire smoke. The country has experienced poor air quality in some areas and visibly darkened snow has been spotted on mountaintops, according to NASA.
More locally, several Australian cities such as Sydney, Melbourne, Canberra and Adelaide, have experienced dangerous air quality levels recently as a result of the smoke, with more than 100 fires still burning in the east of the country, the BBC reported.
Many of these fires are yet to be controlled. However, firefighters announced Monday that they had finally brought Australia's largest "megablaze" under control in what was a rare piece of good news this fire season.
The Gospers Mountain fire had burnt more than 800,000 hectares northwest of Sydney over a three-month period. But firefighters in the state of New South Wales said that "containment prognosis looks promising," with much-needed wet weather forecast for the area in the next few days, AFP reported.
