NASA每日图片：南极臭氧空洞达今年最大值

伤我心太深

2011年10月21日，美国国家航空航天局（下文简称NASA）和国家海洋和大气局的科学家报告说，南极上空的臭氧（Ozone）破坏量已经达到今年的最大值。研究人员利用卫星、地面监测仪器和探空气球观察臭氧空洞，发现它今年最大的宽度和深度在26年的记录里排列前十。

The south pole-centered map above is based on data from the Ozone Monitoring Instrument (OMI) on the Aura satellite. OMI is a spectrometer, built for the NASA satellite by scientists in Denmark and Finland, that measures the amount of sunlight scattered by Earth’s atmosphere and surface. OMI allows scientists to assess how much ozone is present at various altitudes—particularly the stratosphere—and near the ground.

上面以南极为中心的地图是根据“先兆”人造卫星上的臭氧监测仪的数据绘制的。臭氧监测仪是一个分光计，由丹麦和芬兰的科学家为NASA的人造卫星研制，用来测量被大气层和地面散射的太阳光量。依据它的测量数据，科学家们可以估定在地面附近和其它海拔高度有多少臭氧存在——特别是平流层。

The image shows the extent, or geographic area, of the ozone hole at its widest on September 12, 2011, when it stretched 10.05 million square miles (26.03 million square kilometers). The lowest concentration of ozone in the southern stratosphere—that is, the deepest “hole”—occurred on October 9, 2011, when levels descended to 95 Dobson units. The hole isn’t literal; no part of the stratosphere is empty of ozone. But scientists use the hole metaphor to describe the area where ozone drops below a historical concentration of 220 Dobson Units.

这幅图片显示，在今年9月12日臭氧空洞达到其最大宽度时所覆盖的范围和地理区域。当时其面积为1千零5万平方英里（2千6百零3万平方公里）。南极平流层臭氧浓度最低的记录——也就是臭氧空洞最深——发生在今年10月9日，当时读数低至95多布森单位（Dobson Units)。这里所谓的“空洞”不是字面上含义，并不存在任何一处平流层完全没有臭氧，科学家们用空洞这一说法来描述这些臭氧浓度低于历史读数220多布森单位的区域。

“The colder than average temperatures in the stratosphere this year caused a larger than average ozone hole,” said Paul Newman, chief scientist for atmospheres at NASA's Goddard Space Flight Center. “Even though it was relatively large, the area of this year's ozone hole was within the range we’d expect, given the levels of manmade ozone-depleting chemicals that continue to persist in the atmosphere.”

“今年平流层气温低于往年平均温度这一现象，导致了臭氧空洞大于往年的平均值”，在NASA戈达德航天飞行中心负责大气研究的科技总监保罗·纽曼这样说。“尽管今年臭氧空洞的面积相对较大，但还在我们预料的范围之内，考虑到一些由人类造成的损耗臭氧的化学物质依然存在于大气当中”。

Earth's ozone layer protects life by absorbing ultraviolet light, which damages DNA in plants and animals (including humans) and leads to skin cancer. The problem is serious enough that government agencies in New Zealand and Australia regularly warn their citizens to protect themselves from the Sun when the ozone hole develops each year.

臭氧层保护着地球上的生命，因为它能吸收太阳光中的紫外线。紫外线会破坏植物和动物（包括人类）的DNA并导致皮肤癌。臭氧空洞的问题已经非常严重，每年当它变大时，新西兰和澳大利亚的政府机构都会提醒她们的公民要注意保护自己。

The measurements from OMI continue a legacy of monitoring the ozone layer from space that dates back to 1972 with launch of the Nimbus-4 satellite. You can view the historical progress of the ozone hole by visiting NASA’s Ozone Hole Watch page.

通过臭氧监测仪从太空来监控臭氧层的做法可以上溯至1972年，当年发射了大型气象试验卫星。你可以访问NASA的“臭氧空洞监测”网页去查看臭氧空洞的发展过程。

NASA image courtesy Ozone Hole Watch. Caption by Michael Carlowicz and Patrick Lynch.

NASA图片来自“臭氧空洞监测”，说明部分由迈克尔·卡罗威兹和帕特里克·林奇提供。