Ballistics and ash plumes discriminated by Doppler radar
Ballistics and ash plumes discriminated by Doppler radar
复制标题
多普勒雷达识别弹道和火山灰羽流
DOI：
10.1029/2011gl049415
复制
发表时间：
2011
影响因子：
5.2
通讯作者：
F. Donnadieu
中科院分区：
文献类型：
--
作者：
S. Valade;F. Donnadieu
使用地面多普勒雷达(VOLDORAD)记录了(哥斯达黎加)Arenal火山小规模喷发的火山灰羽流。质量载荷的时间-速度分布(即多普勒雷达图)显示出同时记录的两种不同的动态，从不同的速度、寿命和通过雷达波束的传输速度证明了这一点。用一个简单的弹道模型计算的合成多普勒图表明，短时信号与伴随火山灰羽流发射的弹道块体的瞬时投影是一致的。厘米到分米大小的弹道的质量被自信地估计为0.5-7吨，而火山灰羽流的质量松散地限制在5.8×102吨，假设颗粒直径接近喷口2毫米。这些对落在火山山坡上或喷发到大气中的质量比例的定量估计可能有助于对火山灰扩散的建模和监测。
Small scale eruptive ash plumes at Arenal volcano (Costa Rica) were recorded using a ground‐based Doppler radar (VOLDORAD). The time‐velocity distribution of the mass load (i.e., Doppler radargrams) exhibits two contrasted dynamics recorded simultaneously, evidenced by distinctive velocities, life spans, and transit speeds through the radar beam. Synthetic Doppler radargrams computed with a simple ballistic model indicate that the short‐lived signal is consistent with the instantaneous projection of ballistics blocks accompanying the ash plume emission. The mass of centimeter‐ to decimeter‐sized ballistics is confidently estimated at 0.5–7 tons, whereas the ash plume mass is loosely constrained at 5.8 × 102 tons, assuming a particle diameter of 2 mm close to the vent. These quantitative estimates of the mass proportion either falling on the slopes of the volcano or ejected into the atmosphere could help in the modeling and monitoring of tephra dispersal.