Remote Sensing of Aerosol Optical Depth Using an Airborne Polarimeter over North China

Abstract

Abstract:The airborne Atmosphere Multi-angle Polarization Radiometer (AMPR) was employed to perform airborne measurements over North China between 2012 and 2016. Seven flights and synchronous ground-based observations were acquired. These data were used to test the sensor's measurements and associated aerosol retrieval algorithm. According to the AMPR measurements, a successive surface-atmosphere decoupling based algorithm was developed to retrieve the aerosol optical depth (AOD). It works via an iteration method, and the lookup table was employed in the aerosol inversion. Throughout the results of the AMPR retrievals, the surface polarized reflectances derived from air-and ground-based instruments were well matched; the measured and simulated reflectances at the aircraft level, which were simulated based on in situ sun photometer observed aerosol properties, were in good agreement; and the AOD measurements were validated against the automatic sun-photometer (CE318) at the nearest time and location. The AOD results were close; the average deviation was less than 0.03. The MODIS AODs were also employed to test the AMPR retrievals, and they showed the same trend. These results illustrate that (i) the successive surface-atmosphere decoupling method in the retrieved program completed its mission and (ii) the aerosol retrieval method has its rationality and potential ability in the regionally accurate remote sensing of aerosol.

Molecular Beam Epitaxy Scalable Growth of Wafer‐Scale Continuous Semiconducting Monolayer MoTe2 on Inert Amorphous Dielectrics

“…Our transfer characteristics obtained here are the best for monolayer 2H‐MoTe 2 FETs, and also comparable to the best results for few‐layer 2H‐MoTe 2 FETs made on CVD‐grown or exfoliated flakes (Table S1, Supporting Information). It also compares very well with those of single‐crystal‐like MoS 2 FETs with wafer‐scale monolayer channel . The mobilities calculated from 100 devices fall in a narrow range of 19.2–27.0 cm 2 V −1 s −1 , suggesting the relative high‐quality uniformity of our MBE‐derived wafer‐scale monolayer 2H‐MoTe 2 film (Figure h).…”

“…monolayer WS 2 on Au foils and 6 in. monolayer MoS 2 on soda‐lime glasses were demonstrated . By controlling the kinetic rates of nucleation and crystal growth, a centimeter‐scale few‐layer 2H‐MoTe 2 film with domain size up to ≈300 µm was synthesized in 2D limit .…”

“…The large lattice mismatch of −5.44% between the superlattices of (4 × 4) MoTe 2 and (6 × 6) graphene appears to be detrimental for 2H‐phase formation due to strain‐induced 2H → 1Tʹ phase change . Notably, for practical applications, a tedious transfer process from metal catalysts or epitaxial templates to device compatible substrates (e.g., SiO 2 /Si) is inevitable, which adversely degrading the quality of TMDs . Accordingly, a breakthrough in the 2D lateral growth of scalable monolayer TMDs, in particular MoTe 2 , directly on device compatible substrates is highly desired.…”

Characteristic and Driving Factors of Aerosol Optical Depth over Mainland China during 1980–2017

“…Guo et al [33] revealed the spatial and temporal characteristics of AOD values during 1980-2008 over mainland China using the TOMS AOD and MODIS AOD products (2000)(2001)(2002)(2003)(2004)(2005)(2006)(2007)(2008). Meanwhile, many studies on the spatial and temporal variations of AOD values in regional scale in Chinawere conducted using meteorological measurement and satellite signals [10,26,[34][35][36][37][38][39][40]. However, few studies have been made for analyzing the characteristics and driving factors of AOD values in different climate zones and terrain features over mainland China, due to the relative sparse AOD and meteorological measurements.…”

The Normalized Difference Vegetation Index and Angular Variation of Surface Spectral Polarized Reflectance Relationships: Improvements on Aerosol Remote Sensing Over Land

“…The spectral sensitivities of the polarized reflectances obtained from research scanning polarimeter and micropolarimeter measurements over vegetated surfaces were studied previously Waquet, Léon, et al, 2009), and the offsets of the regression lines were determined as small with slopes close to 1. This conclusion has been applied to aerosol retrieval for a number of airborne polarimetric instruments, such as the research scanning polarimeter and the advanced multi-angle polarization radiometer (Qie et al, 2015;Wang et al, 2014Wang et al, , 2017). This conclusion has been applied to aerosol retrieval for a number of airborne polarimetric instruments, such as the research scanning polarimeter and the advanced multi-angle polarization radiometer (Qie et al, 2015;Wang et al, 2014Wang et al, , 2017).…”