Understanding trends in stratospheric NOy and NO2
Understanding trends in stratospheric NOy and NO2
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DOI：
10.1029/2000jd000100
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发表时间：
2001-11
影响因子：
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通讯作者：
C. McLinden;S. Olsen;M. Prather;J. Liley
中科院分区：
文献类型：
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作者：
C. McLinden;S. Olsen;M. Prather;J. Liley
一氧化二氮（N2 O）是一种重要的温室气体，自1980年以来一直以每十年约+3%的速度增长。最近，据报道，自1980年以来，新西兰Lauder上空平流层二氧化氮（NO2）的测量值每十年增加约5%。由于N2 O是平流层中包括NO2在内的奇氮化合物的主要来源，这就提出了一个明显的难题。这里的分析表明，从全球变化框架来看，这些明显相互矛盾的趋势通常是一致的，特别是，如果将平流层臭氧和卤素的共同趋势包括在内。结合使用光化学和三维化学传输模型，我们预测1980-2000年的NO2趋势，在新西兰的兰黛，+4.3%/十年，当考虑这些并发的趋势。其中，只有+2.4%/10年直接归因于N2 O的增加;其余的包括由于臭氧变化引起的+2.5%/10年和-0.6%/10年卤素增加对奇数氮分配的影响。在黄昏期间从天顶散射的太阳光测量的NO2的斜柱密度被发现（1）与真实的垂直柱密度相比，高估了+0.4%/十年的趋势;（2）显示出一个昼夜变化的趋势，在夜间达到最大值，并且在日出和日落期间有很大的梯度，与测量结果吻合得很好。尽管如此，诸如此类的测量对于确定全球变化至关重要，并为理解全球变化提供了一个教训：对测量的时间、位置和几何形状的仔细模拟必须与相关化学物质和气候参数的同步趋势相结合。
Nitrous oxide (N2O), an important greenhouse gas, has been increasing since 1980 at a rate of about +3% per decade. Recently, a notably greater rate of increase of about +5% per decade since 1980 was reported for measurements of stratospheric nitrogen dioxide (NO2) over Lauder, New Zealand. Since N2O is the dominant source of odd-nitrogen compounds in the stratosphere, including NO2, this presents an obvious conundrum. Analysis here shows that these apparently conflicting trends are generally consistent when viewed in a global-change framework, specifically, when concurrent trends in stratospheric ozone and halogens are included. Using a combination of photochemical and three-dimensional chemistry-transport models, we predict a 1980–2000 trend in the NO2, as measured over Lauder, New Zealand, of +4.3%/decade when these concurrent trends are considered. Of this, only +2.4%/decade is attributed directly to the increase in N2O; the remainder includes +2.5%/decade due to the ozone change and −0.6%/decade to the increased halogens' impact on odd-nitrogen partitioning. The slant column densities of NO2, as measured from the zenith scattered sunlight during twilight, are found to (1) overestimate the trend by +0.4%/decade as compared to the true vertical column densities and (2) display a diurnally varying trend with a maximum during the night and large gradients through sunrise and sunset in good agreement with measurement. Nonetheless, measurements such as these are essential for identifying global change and provide a lesson in understanding it: careful simulation of the time, location, and geometry of measurements must be combined with concurrent trends in related chemical species and climate parameters.