Evaluating the Semiempirical $H$– $Q$ Model Used to Calculate the L-Band Emissivity of a Rough Bare Soil

Global-Scale Evaluation of Roughness Effects on C-Band AMSR-E Observations

“…In this study, we considered the value of is equal to zero, but a sensitivity analysis is made for Q varying from 0 to 0.3. Following the result obtained by [23], the values of Nrp for the H and V polarizations were set equal, and we assumed that 0 [23]. According to the Fresnel equations, , * at a specific incidence angle is only related to the soil dielectric properties ( ).…”

“…Generally, surface roughness effects are evaluated using physical variables which can be estimated from field measurements, such as the correlation length and the root-mean-square (RMS) height [21][22][23]. However, traditional measurements of the physical roughness characteristics at the AMSR-E scales are highly uncertain and time consuming [24].…”

“…Montpetit et al [27], recently showed that the latter modeling approach was very effective in modeling the signatures of rough soils at AMSR-E frequencies. Several studies estimated the values of the model parameters ( , , and ) from microwave observations over bare fields [21,22] and computed relationships to link these parameters to the physical parameters measured in the fields (mainly and ) [23,24]. However, it is difficult to use these relationships derived from field measurements or modeling approaches calibrated over very small and homogeneous surfaces to model the signatures of rough soils as measured by space-borne systems.…”

Evaluation of multi-frequency bare soil microwave reflectivity models

“…to the simulated soil reflectivity at L-band using the QHN roughness model. Analysis of the PORTOS-93 data showed that the last two parameters could be neglected (N R = Q R = 0) with a low impact on the accuracy of the SM retrievals (Lawrence, Wigneron, Demontoux, Mialon, & Kerr, 2013). The SMOSREX study also showed that Q R could be neglected but suggested that N R had to be specific for a given polarisation and found that N RV = − 1 and N RH = 1 .…”

Parametric exponentially correlated surface emission model for L-band passive microwave soil moisture retrieval

“…Soil surface roughness has a significant effect on the microwave emission at a given soil moisture condition (Escorihuela et al, 2007;Schwank et al, 2010;Mialon et al, 2012;Lawrence et al, 2013). Roughness generally increases the emissivity and decreases the sensitivity of brightness temperatures to soil moisture.…”