Year-round stratospheric aerosol backscatter ratios calculated from lidar measurements above northern Norway
Year-round stratospheric aerosol backscatter ratios calculated from lidar measurements above northern Norway
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DOI：
10.5194/amt-12-4065-2019
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发表时间：
2019-03
影响因子：
3.8
通讯作者：
A. Langenbach;G. Baumgarten;J. Fiedler;F. Lübken;Christian von Savigny;J. Zalach
中科院分区：
文献类型：
--
作者：
A. Langenbach;G. Baumgarten;J. Fiedler;F. Lübken;Christian von Savigny;J. Zalach
抽象的。提出了一种新的方法，用于计算平流层硫酸盐气溶胶（SSA）层的后向散射比白天和夜间激光雷达测量。使用这种新方法，我们展示了高纬度平流层气溶胶后向散射比的第一个全年数据集。SSA层位于对流层顶和大约30公里之间的高度。它对大气的辐射平衡至关重要。我们在位于挪威北方（北纬69度，东经16度;海拔380米）的北极中层大气研究激光雷达观测站（ALOMAR）使用最先进的瑞利-米氏-拉曼激光雷达。对于夜间测量，气溶胶后向散射比使用发射的激光波长355、532和1064 nm的弹性和非弹性后向散射导出。激光雷达的安装使得能够以约5分钟的时间分辨率和150米的高度进行高质量的测量，从而能够识别垂直厚度小于1公里的平流层气溶胶层中的多个子层。我们引入了一种方法来扩展整个夏天的数据集时，测量需要在永久的白天条件下进行。为此，我们近似的弹性散射的颜色比的后向散射比，并应用校正函数。我们使用从2000年到2018年的夜间测量的约1700小时的355 nm处的平均后向散射比分布来计算校正函数。使用新方法，我们最终基于2014年至2017年期间约4100小时的测量结果提供了一个全年数据集。
Abstract. We present a new method for calculating backscatter ratios of the stratospheric sulfate aerosol (SSA) layer from daytime and nighttime lidar measurements. Using this new method we show a first year-round dataset of stratospheric aerosol backscatter ratios at high latitudes. The SSA layer is located at altitudes between the tropopause and about 30 km. It is of fundamental importance for the radiative balance of the atmosphere. We use a state-of-the-art Rayleigh–Mie–Raman lidar at the Arctic Lidar Observatory for Middle Atmosphere Research (ALOMAR) station located in northern Norway (69∘ N, 16∘ E; 380 m a.s.l.). For nighttime measurements the aerosol backscatter ratios are derived using elastic and inelastic backscatter of the emitted laser wavelengths 355, 532 and 1064 nm. The setup of the lidar allows measurements with a resolution of about 5 min in time and 150 m in altitude to be performed in high quality, which enables the identification of multiple sub-layers in the stratospheric aerosol layer of less than 1 km vertical thickness. We introduce a method to extend the dataset throughout the summer when measurements need to be performed under permanent daytime conditions. For that purpose we approximate the backscatter ratios from color ratios of elastic scattering and apply a correction function. We calculate the correction function using the average backscatter ratio profile at 355 nm from about 1700 h of nighttime measurements from the years 2000 to 2018. Using the new method we finally present a year-round dataset based on about 4100 h of measurements during the years 2014 to 2017.