Tracking and quantifying volcanic SO 2 with IASI, the September 2007 eruption at Jebel at Tair
Tracking and quantifying volcanic SO 2 with IASI, the September 2007 eruption at Jebel at Tair
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使用 IASI 跟踪和量化 2007 年 9 月泰尔杰贝尔火山喷发的火山 SO 2
DOI：
10.5194/acp-8-7723-2008
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发表时间：
2008
影响因子：
6.3
通讯作者：
C. Clerbaux
中科院分区：
文献类型：
--
作者：
L. Clarisse;P. Coheur;A. Prata;D. Hurtmans;A. Razavi;T. Phulpin;J. Hadji;C. Clerbaux
本文以2007年9月泰尔杰贝勒火山喷发为例，论证了红外傅里叶变换光谱仪IASI在火山喷发分析中的潜力。文中给出了详细的辐射传递计算，模拟了各种火山羽流的IASI类透射谱。我们分析了IASI对不同高度SO2的敏感性，并证明了IASI原则上能够向下传感SO2到地表。使用精选的SO2通道的亮度温差作为过滤器，我们能够在塔尔喷发时跟踪Jebel羽流12天，与最先进的UV探测仪不相上下。提出了一种根据SO2吸收谱线的相对强度快速估算火山羽流高度的方法。尽管最近取得了进展，但从最低点观测卫星上提取二氧化硫的垂直剖面仍然是非常具有挑战性的。目前，利用大气传输模型对羽流进行回溯，可以反演出最准确的低谷剖面。通过使用最优估计方法的全逆反演，我们证明了从IASI数据中提取中粗垂直剖面的可能性。通过反演，我们可以给出塔尔喷发时杰贝尔河羽流中SO2总质量的演化。得到了亮度温差与浓度之间的解析关系式，与实验数据吻合较好。IASI的光谱范围还允许恢复火山气溶胶。在塔尔喷发时杰贝尔火山的初始羽流中，发现了以冰粒形式存在的火山气溶胶，我们由此得出了冰粒的大小。
In this paper we demonstrate the potential of the infrared Fourier transform spectrometer IASI in analysing volcanic eruptions, using the September 2007 eruption at Jebel at Tair as an illustrative example. Detailed radiative transfer calculations are presented, simulating IASI-like transmittance spectra for a variety of volcanic plumes. We analyse the sensitivity of IASI to SO2 at different altitudes and demonstrate that IASI is in principle capable of sensing SO2 down to the surface. Using the brightness temperature difference of well chosen SO2 channels as a filter, we are able to track the plume of the Jebel at Tair eruption for 12 days, on a par with state of the art UV sounders. A method is presented for quickly estimating the altitude of a volcanic plume based on the relative intensities of the SO2 absorption lines. Despite recent advances, it is still very challenging to retrieve vertical profiles of SO2 from nadir viewing satellites. Currently the most accurate profiles in nadir are retrieved using backtracking of the plume with atmospheric transport models. Via full inverse retrievals using the optimal estimation method, we show the possibility of extracting medium coarse vertical profiles from IASI data. The retrieval allows us to present an evolution of the total mass of SO2 in the plume for the Jebel at Tair eruption. An analytical relation is derived between brightness temperature differences and concentrations, which fits the experimental data very well. The spectral range of IASI also allows retrieval of volcanic aerosols. In the initial plume of the Jebel at Tair eruption, volcanic aerosols were found in the form of ice particles, for which we derived particle sizes.