Volcanic Ash Sensing EECS 823 Radar Remote Sensing Project Presented by Susobhan Das

Outline…… Introduction Volcanic Ash Classification Radar System Specification volcanic ash radar retrieval Algorithem (VARR) Volcanic Ash Modeling Conclusion Reference

Possible Disaster due to Volcanic Ash Wet ash is electrically conductive may cause short circuits. Due to heavy weight it may cause physical damage. Frequent lightning due to electrically charged ash particles. Increase air traffic Volcanic ash in flight engine may cause failure. Health Hazard due to fine ash particle Disadvantage of Satellite System Available time of scanning (only mins) Poor Spectral Resolution Introduction

Mean Diameter D n [mm] Average Mean Diameter Proportionality and σ Dn and Diameter D range Fine Ash0.0120% Coarse Ash0.120% Lapilli1.020% Ash Concentration C a [gm -3 ] Average Concentration Proportionality and σ Ca and Concentration C a Range Light0.150% Moderate1.050% Intense5.050% Volcanic Ash Classification

Band Frequency Range(GHz) Wavelength Range (cm) Rayleigh Maximum Diameter (mm) L S C X Ku K Ka V W Frequency Band and corresponding Rayleigh Scattering Diameter

Radar System Characteristics Radar S band Radar C band Radar X band BandSCX Frequency Range GHz GHz9.375GHz TransmitterMagnetron Transmit Peak Power 600Kw250Kw50Kw RF Pulse Width0.8 to 2 ms0.5 to 2 ms PRF HZ Antenna TypeCirc. Parabola Antenna Gain45dB PolarizationLinear H H and V Half-Power Beamwidth 1.0 degree 1.3 degree Reflector diameter 8.5 meters4.2 meters2.1 meters Sensitivity(MDS)-113 dBm -112 dBm Receiver Noise Figure 2 dB Radar System Specification

Z Hm Ash Classification Ash Retrieval C a, R a Radar Specs Ash Micro Physical Radar Model Ash Data volcanic ash radar retrieval (VARR) [1]

is Backscattering cross section at horizontal polarization is particle size distribution is Radar equivalent Reflectivity factor is the ash complex dielectric factor of ash particle varies from 5.5 to 6.5 from S-band to K-band varies from 0.08 to 0.27 from S-band to K-band Dielectric factor of water is 0.93 and ice is Comparing with water and ice, ash particles are 2.4 times less reflective than water and 2 times more reflective than ice. Horizontally Polarized Radar Reflectivity Volcanic Ash Modeling

Set:1 a v =7.46 m/s b v  empirical coefficient =1 for 5 to 10 km of height Set:2 a v =2.504 m/s b v =0.472 Set:1 Set:2 Terminal Fall velocity in still Air

ρ a = ash density D n =Average mean Diameter Ash Fall Rate Ash mass concentration

Fine Ash D n =0.01mm Coarse Ash D n =0.1mm Lapoilli Ash D n =1mm Intense Moderate Light Particle Size Density

P t is peak transmitted power τ is pulse length 3 and Ф 3 are 3dB beamwidth in vertical and horizontal direction G 0 is antenna Gain L f is receiver filtering loss Optimization

Conclusion Frequency Band depending on ash particle diameter Optimization between Antenna transmitted power and range

Reference 1.Frank Silvio Marzano, Gianfranco Vulpiani, “Volcanic Ash Cloud Retrieval by Ground-based Microwave Weather Radar” ieee transactions on geoscience and remote sensing, vol. 44, no. 11, november Frank Silvio Marzano, Gianfranco Vulpiani, and William I. Rose,” Microphysical Characterization of Microwave Radar Reflectivity Due to Volcanic Ash Clouds” ieee transactions on geoscience and remote sensing,ieee transactions on geoscience and remote sensing, vol. 44, no. 2, november Stefano Corradini, Luca Merucci, and Arnau Folch,Volcanic Ash Cloud Properties: Comparison Between MODIS Satellite Retrievals and FALL3D Transport Model” ieee transactions on geoscience and remote sensing,ieee transactions on geoscience and remote sensing, vol. 8, no. 2, november 2011