Stratospheric ozone over the United States in summer linked to observations of convection and temperature via chlorine and bromine catalysis
Stratospheric ozone over the United States in summer linked to observations of convection and temperature via chlorine and bromine catalysis
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DOI：
10.1073/pnas.1619318114
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发表时间：
2017-06-20
影响因子：
11.1
通讯作者：
Wofsy, Steven C.
中科院分区：
文献类型：
--
作者：
Anderson, James G.;Weisenstein, Debra K.;Wofsy, Steven C.
我们目前的观测定义（i）的频率和深度的对流渗透到平流层的水在美国夏季使用下一代雷达系统;（ii）的高度依赖的分布的无机氯建立在同一坐标系的雷达观测;（iii）夏季美国上空平流层的高分辨率温度结构，它能分辨空间和结构的变化，包括重力波的影响;以及（iv）对于占主导地位的卤素、氢和氮催化循环，臭氧的催化损失率的放大。气象雷达观测到，平均每年夏天有大约2，000场风暴达到可获得无机氯迅速增加的高度，再加上观测到的温度，预示着无机氯有可能在无处不在的硫酸盐-水气溶胶上迅速多相催化转化为自由基形式;这反过来又涉及与夏季美国中部平流层臭氧损失有关的风险因素，其基础是减少北极平流层臭氧的同一反应网络。在北美季风的驱动下，美国上空上层反气旋流的夏季发展提供了一种保留对流注入水的方法，从而延长了大平原上空催化臭氧损失的时间。可信的美国夏季紫外线剂量的十年期预报需要了解这一动力学和光化学系统对CO2和CH 4水平增加造成的气候强迫的反应。
We present observations defining (i) the frequency and depth of convective penetration of water into the stratosphere over the United States in summer using the Next-Generation Radar system; (ii) the altitude-dependent distribution of inorganic chlorine established in the same coordinate system as the radar observations; (iii) the high resolution temperature structure in the stratosphere over the United States in summer that resolves spatial and structural variability, including the impact of gravity waves; and (iv) the resulting amplification in the catalytic loss rates of ozone for the dominant halogen, hydrogen, and nitrogen catalytic cycles. The weather radar observations of similar to 2,000 storms, on average, each summer that reach the altitude of rapidly increasing available inorganic chlorine, coupled with observed temperatures, portend a risk of initiating rapid heterogeneous catalytic conversion of inorganic chlorine to free radical form on ubiquitous sulfate-water aerosols; this, in turn, engages the element of risk associated with ozone loss in the stratosphere over the central United States in summer based upon the same reaction network that reduces stratospheric ozone over the Arctic. The summertime development of the upper-level anticyclonic flow over the United States, driven by the North American Monsoon, provides a means of retaining convectively injected water, thereby extending the time for catalytic ozone loss over the Great Plains. Trusted decadal forecasts of UV dosage over the United States in summer require understanding the response of this dynamical and photochemical system to increased forcing of the climate by increasing levels of CO2 and CH4.