Severe chemical ozone loss in the Arctic during the winter of 1995–96
Severe chemical ozone loss in the Arctic during the winter of 1995–96
复制标题
1995-96 年冬季北极化学臭氧损失严重
作者：
R. Müller;P. Crutzen;J. Grooβ;Christoph Bürhl;J. Russell;H. Gernandt;D. McKenna;A. Tuck
严重的平流层臭氧消耗是由于在极涡和中纬度之间的空气交换有限以及极涡部分暴露于阳光下的时期，由于极地平流层云的存在，氯化学发生扰动的结果。在南极洲的春季，这些条件一直存在。在北极，广泛的PSC形成只发生在最寒冷的冬天，当温度下降到南极通常发现的那样低时。此外，臭氧水平在冬末和早春显着高于相应的南半球季节，通常强烈扰动大气动力学，，。由于这些原因，北极的臭氧化学损失很难量化。在这里，我们使用的相关性CH 4和O3在北极极涡区分臭氧浓度的变化，由于化学和动力学效应。我们的研究结果表明，1996年1月至3月期间，120-160个多布森单位（DU）的臭氧被化学破坏，这一损失大于1985年首次报告“臭氧洞”时在南极洲观察到的损失。这一损失超过了同期臭氧总量因动力效应而预计的增加，导致观测到的净减少量约为50 DU。北极平流层温度极低和平流层氯含量高的同时发生，导致臭氧流失。由于平流层冷却和氯浓度升高预计将持续几十年，因此类似的消耗可能会再次发生。
Severe stratospheric ozone depletion is the result of perturbations of chlorine chemistry owing to the presence of polar stratospheric clouds (PSCs) during periods of limited exchange of air between the polar vortex and midlatitudes and partial exposure of the vortex to sunlight,,,. These conditions are consistently encountered over Antarctica during the austral spring. In the Arctic, extensive PSC formation occurs only during the coldest winters, when temperatures fall as low as those regularly found in the Antarctic,,. Moreover, ozone levels in late winter and early spring are significantly higher than in the corresponding austral season,,, and usually strongly perturbed by atmospheric dynamics,,,. For these reasons, chemical ozone loss in the Arctic is difficult to quantify. Here we use the correlation between CH4and O3in the Arctic polar vortex to discriminate between changes in ozone concentration due to chemical and dynamical effects. Our results indicate that 120–160 Dobson units (DU) of ozone were chemically destroyed between January and March 1996—a loss greater than observed in Antarctica in 1985, when the ‘ozone hole’ was first reported,. This loss outweighs the expected increase in total ozone over the same period through dynamical effects, leading to an observed net decrease of about 50 DU. This ozone loss arises through the simultaneous occurrence of extremely low Arctic stratospheric temperatures, and large stratospheric chlorine loadings. Comparable depletion is likely to recur because stratospheric cooling, and elevated chlorine concentrations, are expected to persist for several decades.