Retrieval of Aerosol Microphysical Properties Based on the Optimal Estimation Method: Information Content Analysis for Satellite Polarimetric Remote Sensing Measurements

Abstract

ABSTRACT:This paper evaluates the information content for the retrieval of key aerosol microphysical and surface properties for multispectral single-viewing satellite polarimetric measurements cantered at 410, 443, 555, 670, 865, 1610 and 2250 nm over bright land. To conduct the information content analysis, the synthetic data are simulated by the Unified Linearized Vector Radiative Transfer Model (UNL-VTM) with the intensity and polarization together over bare soil surface for various scenarios. Following the optimal estimation theory, a principal component analysis method is employed to reconstruct the multispectral surface reflectance from 410 nm to 2250 nm, and then integrated with a linear one-parametric BPDF model to represent the contribution of polarized surface reflectance, thus further to decouple the surface-atmosphere contribution from the TOA measurements. Focusing on two different aerosol models with the aerosol optical depth equal to 0.8 at 550nm, the total DFS and DFS component of each retrieval aerosol and surface parameter are analysed. The DFS results show that the key aerosol microphysical properties, such as the fine-and coarse-mode columnar volume concentration, the effective radius and the real part of complex refractive index at 550 nm, could be well retrieved with the surface parameters simultaneously over bare soil surface type. The findings of this study can provide the guidance to the inversion algorithm development over bright surface land by taking full use of the single-viewing satellite polarimetric measurements.

Study on the spectral reconstruction of typical surface types based on spectral library and principal component analysis

“…In order to test the spectral reconstruction based on the linear combination model, the surface information of four common bands for satellite remote sensing, including 490, 555, 670 and 865 nm [16][17][18][19][20][21] , are used to the spectral reconstruction. Figure 6 shows the scatter plots of the reconstructed and true surface reflectance at 440 nm, and Figure 7 shows the reconstructed reflectance results at 810nm.…”

“…In order to test the spectral reconstruction based on the linear combination model, the surface information of four common bands for satellite remote sensing, including 490, 555, 670 and 865 nm [16][17][18][19][20][21] , are used to the spectral reconstruction. Corresponding to Eq.…”

“…Principal component analysis (PCA) has been widely used in the study of spectral compression and reconstruction, in which, a spectral data set can be decomposed into the linear combinations of several main spectral components [9][10][11][12] . Previous studies have shown that in the visible range of 400-700 nm, the first six principal components (PCs) can meet the needs of spectral reconstruction [13][14] ; while for the wavelength range of 400-2500 nm, [12][13][14][15][16][17][18][19][20] PCs are needed to reconstruct the vegetated surface spectra 15 .…”

Optimal Estimation Retrieval of Aerosol Fine-Mode Fraction from Ground-Based Sky Light Measurements

“…The outputs of UNL-VRTM include not only the four elements of the Stokes vector but also their sensitivities (Jacobians) with respect to aerosol and surface model parameters. The UNL-VRTM is widely used to develop the inversion algorithm for retrieval of aerosol and surface properties from ground-based, airborne, and satellite measurements [31,[40][41][42][43]].…”