检测加那利群岛的火山灰雨

The Canary Islands, and especially the island of La Palma, has been experiencing the volcanic eruption of Cumbre Vieja since September 2021. The volcanic eruption has been ongoing in the popular tourist destination for several months, with lava flows causing damage to property, ash plumes leading to disruptions to air travel and poor air quality caused by volcanic ash and noxious gases impacting the health of local inhabitants.

Vaisala的LIDAR天花板CL61和去极化能力自10月底以来，一直在高空测量火山灰层。CL61安装在埃尔帕索市政厅的庭院，位于库姆德·维耶（Cumbre Vieja）北部的海平面723米。La Palma国际机场位于东海岸小镇圣克鲁斯附近。

图片

On the left, CL61 Lidar Ceilometer installed at El Paso Town Hall (picture by AEMET). On the right, map of La Palma with marker indicating the CL61 location north from Cumbre Vieja (picture Google Maps).

CL61数据用于理解La Palma上方的火山灰层运动，但也通知El Paso的人们可能会降雨。在大多数情况下，盛行的风将灰羽推向西南，但偶尔在埃尔帕索和机场上方也发现了羽毛，从而为公众提供了预防措施，例如留在室内或戴上口罩和戴口罩和戴面具，防护服，并因高灰分浓度而导致空中旅行。

Volcanic ash above the boundary layer

以下是CL61火山灰测量的几个测量示例。第一个示例显示了在时间/高度图中衰减的反向散射曲线。在这张照片中，我们看到边界层内有强度的信号（最多1,000米），但从07UTC开始，在约2,000米处高空上方。由于灰烬粒子靠近边界层的顶部，也形成了云，这些灰分被视为图上的深红信号。

图片

CL61 Attenuated backscatter profile for October 29 2021

当我们使用平行和交叉极化信号之间的去极化比率的去极化信号观察到同一天，我们可以清楚地看到边界层上方的高空火山灰层。看到灰分层的脱酚比为0.3至0.4，在这种情况下，高空的层在La Palma Island上方行进，并未在地面上引起灰分沉积。边界层顶部的云层从16UTC到20UTC是液态云层，因为它的depol比接近0.0，而所有其他云也是今天在边界层顶部形成的所有其他云。

图片

CL61 depolarization ratio profile on October 29 2021

火山灰雨

The second example shows volcanic ash rain which was also observed on the ground level. The first picture is showing the Volcanic Ash Advisory Center (VAAC, Meteo France Toulouse) forecast of ash layer on October 30 2021. From this we can see the forecast indicating the layer to be also above town of El Paso and CL61.

图片

VAAC forecast for October 30 2021 at La Palma (picture by VAAC)

CL61在2021年10月30日减弱了反向散射档案shows high signal on boundary layer but also layers above it. Especially high signal close to ground from 05UTC to 22UTC.

图片

CL61在2021年10月30日减弱了反向散射档案

When investigating the depolarization ratio profile for the same day we can see the volcanic ash layer aloft but also much of the volcanic ash within the boundary layer. We can see the ash layer aloft above the boundary layer at around 2,000 meters height all day. The most interesting in this plot is to observe the volcanic ash rain which caused an accumulation of ash on the ground. The depolarization signal indicates the deposition which was also very well visible on the ground by observers. Again, the depol ratio values at 0.3 to 0.4 which is well in line with anticipated volcanic ash depolarization ratio signal.

图片

CL61 depolarization profile on October 30 2021

This study of using CL61 with depolarization capability to observe volcanic ash at La Palma is made in co-operation withaemet。

图片

观看我们最近的网络研讨会“超越云”，以了解有关航空应用程序CL61的更多信息。