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A Deep-Learning and Transfer-Learning Hybrid Aerosol Retrieval Algorithm for FY4-AGRI:Development and Verification over Asia

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Engineering 2024年第7期38卷 164-174页

作者： Disong Fu Hongrong Shi Christian AGueymard Dazhi Yang Yu Zheng Huizheng Che Xuehua Fan Xinlei Han Lin Gao Jianchun Bian minzheng duan Xiangao Xia Key Laboratory of Middle Atmosphere and Global Environment Observation Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 10029China Key Laboratory of Cloud-Precipitation Physics and Severe Storms Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China Solar Consulting Services ColebrookNH 03576USA School of Electrical Engineering and Automation Harbin Institute of TechnologyHarbin 150006China State Key Laboratory of Severe Weather&Key Laboratory of Atmospheric Chemistry Institute of Atmospheric Composition and Environmental MeteorologyChinese Academy of Meteorological SciencesChina Meteorological AdministrationBeijing 100081China National Institute of Natural Hazards Ministry of Emergency Management of ChinaBeijing100085China Key Laboratory of Compound and Chained Natural Hazards Dynamics Ministry of Emergency Management of ChinaBeijing 100085China h National Satellite Meteorological Center China Meteorological AdministrationBeijing 100081China University of Chinese Academy of Sciences Beijing 100049China

The Advanced Geosynchronous Radiation Imager(AGRI)is a mission-critical instrument for the Fengyun series of *** acquires full-disk images every 15 min and views East Asia every 5 min through 14 spectral bands,enabling the detection of highly variable aerosol optical depth(AOD).Quantitative retrieval of AOD has hitherto been challenging,especially over *** this study,an AOD retrieval algorithm is proposed that combines deep learning and transfer *** algorithm uses core concepts from both the Dark Target(DT)and Deep Blue(DB)algorithms to select features for the machinelearning(ML)algorithm,allowing for AOD retrieval at 550 nm over both dark and bright *** algorithm consists of two steps:①A baseline deep neural network(DNN)with skip connections is developed using 10 min Advanced Himawari Imager(AHI)AODs as the target variable,and②sunphotometer AODs from 89 ground-based stations are used to fine-tune the DNN ***-of-station validation shows that the retrieved AOD attains high accuracy,characterized by a coefficient of determination(R2)of 0.70,a mean bias error(MBE)of 0.03,and a percentage of data within the expected error(EE)of 70.7%.A sensitivity study reveals that the top-of-atmosphere reflectance at 650 and 470 nm,as well as the surface reflectance at 650 nm,are the two largest sources of uncertainty impacting the *** a case study of monitoring an extreme aerosol event,the AGRI AOD is found to be able to capture the detailed temporal evolution of the *** work demonstrates the superiority of the transfer-learning technique in satellite AOD retrievals and the applicability of the retrieved AGRI AOD in monitoring extreme pollution events.

关键词： Aerosol optical depth Retrieval algorithm Deep learning Transfer learning Advanced Geosynchronous Radiation Imager

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三频雷达遥感云参数能力的模拟与初步分析

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大气科学 2024年第5期48卷 2004-2014页

作者：霍娟段民征韩瑽琤毕永恒中国科学院大气物理研究所中层大气和全球环境探测重点实验室(LAGEO) 北京100029

短波雷达在观测云内粒子微物理属性方面具有优势,是探测全球水循环重要环节——云的强有力探测工具。本文简要回顾了云雷达探测的理论基础,从雷达探测基本原理出发,借助小粒子电磁波散射理论和方法,建立了一套多波长雷达观测正演(前向)... 详细信息

短波雷达在观测云内粒子微物理属性方面具有优势,是探测全球水循环重要环节——云的强有力探测工具。本文简要回顾了云雷达探测的理论基础,从雷达探测基本原理出发,借助小粒子电磁波散射理论和方法,建立了一套多波长雷达观测正演(前向)模型(Radar Simulation Package,简称RSP),并利用RSP对当前主流的三种典型波长X波段(9.5 GHz、3 cm)、Ka波段(35 GHz、8 mm)和W波段(94 GHz、3 mm)短波雷达的遥感探测能力开展了模拟分析。通过与瑞利法计算结果相比较,证实RSP法的计算精度可靠准确。基于RSP法模拟结果,建立了液水含量(LWC)与雷达反射率因子(Ze)、有效粒子半径(re)与Ze之间幂指数形式的反演关系;建立了利用不同云层高度处两波长的反射率因子差值,反演云层平均LWC的反演关系等。本文工作对如何利用雷达探测参数提取液态云滴的微物理参数方法进行了探讨,一方面为多波长雷达探测云特征获得更准确的理论认识,另一方面为云微物理参数的反演提供理论依据和分析手段。

关键词：雷达毫米波微物理反演云模拟

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A Differential Optical Absorption Spectroscopy Method for X_(CO_2) Retrieval from Ground-Based Fourier Transform Spectrometers Measurements of the Direct Solar Beam

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Advances in Atmospheric Sciences 2015年第8期32卷 1119-1128页

作者： HUO Yanfeng duan minzheng TIAN Wenshou MIN Qilong Key Laboratory for Semi-Arid Climate Change of the Ministry of Education College of Atmospheric Sciences Lanzhou University Key Laboratory of Middle Atmosphere and Global Environment Observation Institute of Atmospheric Physics Chinese Academy of Sciences Wuhan University Atmospheric Science Research Center State University of New York

A differential optical absorption spectroscopy （DOAS）-like algorithm is developed to retrieve the column-averaged dry- air mole fraction of carbon dioxide from ground-based hyper-spectral measurements of the direct solar beam. Different to the spectral fitting method, which minimizes the difference between the observed and simulated spectra, the ratios of multiple channel-pairs--one weak and one strong absorption channel--are used to retrieve Xc02 from measurements of the shortwave infrared （SWIR） band. Based on sensitivity tests, a super channel-pair is carefully selected to reduce the effects of solar lines, water vapor, air temperature, pressure, instrument noise, and frequency shift on retrieval errors. The new algorithm reduces computational cost and the retrievals are le^s sensitive to temperature and H20 uncertainty than the spectral fitting method. Multi-day Total Carbon Column Observing Network （TCCON） measurements under clear-sky conditions at two sites （Tsukuba and Bremen） are used to derive Xc02 for the algorithm evaluation and validation. The DOAS-like results agree very well with those of the TCCON algorithm after correction of an airmass-dependent bias.

关键词： CO2 Retrieval ground-based measurement hyper-spectrum shortwave infrared band

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Algorithm for retrieving surface pressure from hyper-spectral measurements in oxygen A-band

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Chinese Science Bulletin 2014年第14期59卷 1492-1498页

作者： Hailei Liu minzheng duan Daren L Yan Zhang Institute of Atmospheric Physics Chinese Academy of Sciences Chengdu University of Information Technology Beijing Institute of Remote Sensing Information Application

An algorithm for retrieving the surface pressure from oxygen A-band measurements in the future Chinese CO2satellite(CarbonSpec/TanSat)was *** ful physical radiative transfer model,vector radiative transfe model based on successive order of scattering,which i based on the successive order of scattering approach,wa used to simulate the measurements of CarbonSpec/TanSat as well as the kernel matrix in the inversion algorithm,and then the surface pressure and other related atmospheric parameters such as aerosol optical depth(AOD),surface albedo,and temperature were derived through optima estimation *** of the algorithm to surface albedo,solar zenith angle(SZA),viewing zenith angle(VZA),aerosol type,and AOD were investigated,and the results showed that the absolute error of retrieved surface pressure increases with decreasing surface albedo o increasing SZA and *** accuracy of\4 hPa ove bright surfaces(surface albedo C0.15)could be derived fo various SZAs and viewing ***,the algorithm can simultaneously retrieve the surface albedo AOD,and its vertical distribution indicated by scale

关键词：表面压力求逆算法光谱测量波段氧气检索气溶胶光学厚度地表反照率

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Effects of spectral sampling rate and range of CO_2 absorption bands on XCO_2 retrieval from TanSat hyperspectral spectrometer

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Chinese Science Bulletin 2014年第14期59卷 1485-1491页

作者： Yi Liu Zhaonan Cai Dongxu Yang Yuquan Zheng minzheng duan Daren L Key Laboratory of Middle Atmosphere and Global Environment Observation Institute of Atmospheric PhysicsChinese Academy of Sciences Changchun Institute of Optics Fine Mechanics and PhysicsChinese Academy of Sciences

The spectral sampling rate and range of CO2absorption bands are critical for the optimal design of hyperspectral instrument for CO2observation *** of spectra in space-based spectrometer significantly contaminates signals measured in the CO21.61 *** CO2dry-air column(XCO2)error due to spectral undersampling can be up to*1 ppm,which is the target precision of the Chinese Carbon Satellite(TanSat)for a single *** error depends on surface albedo,solar zenith angle,and scattering properties in the *** spectral sampling rate is recommended to be greater than 2.0 pixels per full width at half maximum to avoid *** of spectral resolution and the use of narrower spectral regions can improve spectral sampling with little changes in CO2retrieval sensitivity without losing much *** full-band approach provides direct constraints on the wavelength-dependent surface albedo and particle scattering from the *** keep a broader band,we recommend reduction of the spectral resolution by a factor of two.

关键词：采样速率高光谱 CO2 光谱仪吸收带检索地表反照率光谱分辨率

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Observed and simulated features of the CO_2 diurnal cycle in the boundary layer at Beijing and Hefei,China

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Chinese Science Bulletin 2014年第14期59卷 1529-1535页

作者： Yinan Wang Daren L Qian Li minzheng duan Fei Hu Shunxing Hu Laboratory of Middle Atmosphere and Global Environment Observation Institute of Atmospheric PhysicsChinese Academy of Sciences University of Chinese Academy of Sciences Laboratory of Atmospheric Boundary Layer and Atmospheric Chemistry Institute of Atmospheric PhysicsChinese Academy of Sciences Anhui Institute of Optics and Fine Mechanics Chinese Academy of Sciences

The mechanism of the CO2diurnal cycle is a basis for investigating the carbon budget and its impacts on climate and environment *** diurnal variations in CO2concentration based on observations and modeling have been studied ***,few studies have focused on the pattern of the CO2diurnal cycle in *** this study,a three-dimensional global chemical transport model,Goddard Earth Observing System(GEOS)-Chem,was applied to simulate the CO2concentration and its variation over China from 2004 to ***,we also analyzed the CO2concentration as observed by two eddy covariance flux observation towers,one located in Beijing(39°580N,116°220E)and one in Hefei(31°550N,117°100E),using LI-COR 7500A infrared gas *** showed the amplitude of the CO2diurnal cycle at Hefei to be larger than at Beijing,due to stronger ecological ***-Chem successfully captured the main aspects of the diurnal cycle of the CO2concentration in the boundary layer observed at both Beijing and ***,some discrepancies between the model and observations did exist;specifically,the model tended to underestimate the amplitude of the CO2diurnal *** data also showed that traffic emissions significantly enhanced the CO2concentration in the boundary layer.

关键词：地球观测系统 CO2浓度模拟功能边界层昼夜合肥北京周期

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A Polarized Radiative Transfer Model Based on Successive Order of Scattering

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Advances in Atmospheric Sciences 2010年第4期27卷 891-900页

作者：段民征 Qilong MIN 吕达仁 Key Laboratory for Middle Atmosphere and Global Environment Observation Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 Atmospheric Sciences Research Center State University of New York Albany NY 12203

Based on Successive Order of Scattering approach, a full Vector Radiative Transfer model （SOSVRT） for vertically inhomogeneous plane-parallel media has been developed. To overcome the computational burdens of convergence, a simple approximation technique by truncating scattering orders with a geometric series is used to reduce computational time. Analytical Fourier decomposition of phase matrix with three symmetry relationships and two mutual inverse operators have been implemented to further improve the computational efficiency. To improve the accuracy, a post-processing procedure is implemented to accurately interpolate the Stokes vector at arbitrary angles. Comparisons with the benchmarks for an atmosphere of randomly orientated oblate spheroids show excellent agreement for each Stokes parameter （within 0.1%）. SOSVRT has been tested for different atmospheric condition against RT3, which is based on doubling-adding method, and the results prove that SOSVRT is accurate and much more efficient in vector radiative transfer modeling, especially for optical thin atmosphere, which is the most common case in polarized radiative transfer simulations. SOSVRT is written in Fortran 90 and the code is freely accessible by contacting the author.

关键词： radiative transfer polarization successive order of scattering scattering

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基于逐次散射法的海洋—大气矢量辐射传输模式

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遥感技术与应用 2014年第2期29卷 181-188,211页

作者：李姣段民征覃军中国地质大学(武汉)大气物理与大气环境研究所湖北武汉430074 中国科学院大气物理研究所中层大气与全球环境探测开放实验室北京100029

首先推导了粗糙洋面双向偏振反射模型pBRDF(Bidirectional Polarized Reflectance Distribution Function),并将其与SOSVRT(Successive Order of Scattering Radiative Transfer)矢量辐射传输模式耦合,建立了海洋—大气耦合的矢量辐射传输模式,并对该耦合模式的模拟结果与前人模拟结果进行对比,验证了该耦合模式的可靠性与有效性。不同大气和洋面状态、不同高度的主平面内辐射强度和偏振度的模拟结果表明:pBRDF模型可以很好地模拟不同风速下洋面的偏振反射分布特征;洋面在特定角度具有很高的偏振度,并对大气顶的偏振辐射有很大影响。因此,该耦合模式可以更准确地处理辐射光谱在海洋—大气两种介质间的传输问题,对矢量辐射传输、大气遥感问题的研究有重要意义。

关键词：辐射传输逐次散射法海表偏振

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一个简单的非水平均匀的大气临边矢量辐射传输模式

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遥感技术与应用 2014年第5期29卷 735-743页

作者：郜婧婧段民征孙淑珍华北电力大学数理学院北京102206 中国科学院大气物理研究所中层大气和全球环境探测重点实验室北京100029

临边或掩星探测是通过对大气的切片式观测方式所建立的反演方法,可以获取大气要素垂直分层的精细分布,是卫星遥感的一种重要方式和方向。目前已有的临边大气辐射传输模式大部分是基于水平均匀分布的一维模式,且以不包含大气偏振模拟的... 详细信息

临边或掩星探测是通过对大气的切片式观测方式所建立的反演方法,可以获取大气要素垂直分层的精细分布,是卫星遥感的一种重要方式和方向。目前已有的临边大气辐射传输模式大部分是基于水平均匀分布的一维模式,且以不包含大气偏振模拟的模式为主,而偏振是未来大气遥感的重要手段,特别是在紫外波段的临边探测。为满足我国下一代临边探测的需求,编写了一个基于逐次散射法的临边矢量辐射传输模式,该模式可实现对临边辐射的4个Stokes参数的模拟,并考虑了大气水平非均匀分布的影响。在环境参数完全相同条件下,将标量计算方式下辐射强度的模拟结果与郭霞等的LGLTRAN模式的模拟结果进行比较,结果验证了模式的合理性。在此基础上对不同大气分层条件下的临边Stokes矢量进行了模拟和简单的分析。

关键词：临边非水平均匀矢量辐射传输

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A FAS approach for stabilization of generalized chained forms: part 1. Discontinuous control laws

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Science China(Information Sciences) 2024年第2期67卷 118-143页

作者： Guang-Ren duan Center for Control Theory and Guidance Technology Harbin Institute of Technology Center for Control Science and Technology Southern University of Science and Technology

In this paper, a type of general nonholonomic systems is proposed, which contains both the Brockett’s two example systems, and their extended n-dimensional chained forms, as special cases. For the stabilization of such systems, a stabilizing controller is proposed based on the fully actuated system(FAS)approach, which is discontinuous at the origin but time-invariant when the open-loop system is time-invariant,and drives the feasible trajectories of the system to the origin exponentially. Furthermore, the proposed FAS approach is also extended to the sub-normal system case and the time-delay system case.

关键词： nonholonomic systems feedback stabilization exponential convergence sub-fully actuated systems time-delay systems

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