Coherent Wave Effects in Layering & Incoherent Model Inter-Comparison

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Coherent Wave Effects in Layering & Incoherent Model Inter-Comparison. UWBRAD meeting May 20, 2014 Leung Tsang, Shurun Tan, Tianlin Wang. Part I. Physics behind coherent wave effects. Magnitude of and depends on permittivity contrast – density fluctuation effects - PowerPoint PPT Presentation

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UWBRAD meetingMay 20, 2014Leung Tsang, Shurun Tan, Tianlin Wang Coherent Wave Effects in Layering&Incoherent Model Inter-ComparisonPhysics behind coherent wave effects

Part IModel of Layering EffectsDensity profile: (Drinkwater 2004)Modified by damping Gaussian Noise (Macelloni and Brogioni) Standard deviationDamping factorLayer thickness:Average of layer thicknessStandard deviation of layer thicknessTotal layer thicknessReflection and EmissionEffective permittivity:Absorption coefficient:No scattering effects included in current model. Focus on coherent wave interference.Maxwell-Garnett mixing formulaIce permittivity empirical model of Matzler and Wegmuller, 2006 Temperature ProfileTemperature profile (Jezek et al. 2013)

Tb of coherent model shows resonance for fixed layer thickness with density fluctuation.

150 realizationIncoherent model is not sensitive to layer thickness variation.

Tb of coherent model shows resonance for low frequency, and the resonance mitigates for higher frequency.

With moderate layer thickness variation, Tb of coherent model gets a minimum around 1GHz.

1950 realization

150 realization

When average layer thickness is large, Tb of coherent model converges to incoherent model as standard deviation of layer thickness increases.150 realization

Note there is no strong resonance over angle after statistical average. The difference in Tb between coherent and incoherent model is due to the resonance with respect to frequency.150 realization150 realizationIncoherent approachPart II Incoherent model Inter-comparison

Temperature profile with seasonal swing near surfaceSmooth density profile

Layer thickness:0 to 100m 1000 layers 10 cm each100 to 300m400 layers 50 cm each 300 to 3200m579 layers 5.0086m eachAt 3200m water base at ~269K (temp of the last ice layer) with =85.9 + 12.72i

Noisy density profile 1 realization

Noisy density profile 150 realization average

UW model with scattering is lower than UW model without scattering by about 3K.

UW model without scattering is slightly larger than Marcos result for H-pol implying that the scattering effects accounts more with multiple reflection.

UW model with scattering is closer to Marcos results also implying the increase of scattering importance with multiple reflection.