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Assessment of Retrieved N₂O, NO₂, and HF Profiles from the Atmospheric Infrared Ultraspectral Sounder Based on Simulated Spectra

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SENSORS 2018年第7期18卷 2209-2209页

作者： Wang, Hongmei Li, Xiaoying Xu, Jian Zhang, Xingying Ge, Shule Chen, Liangfu Wang, Yapeng Zhu, Songyan Miao, Jing Si, Yidan Chinese Acad Sci Inst Remote Sensing & Digital Earth State Key Lab Remote Sensing Sci Beijing 100101 Peoples R China Univ Chinese Acad Sci Beijing 100049 Peoples R China German Aerosp Ctr DLR Remote Sensing Technol Inst D-82234 Oberpfaffenhofen Germany China Meteorol Adm Natl Satellite Meteorol Ctr Beijing 100081 Peoples R China China Ctr Resources Satellite Data & Applicat Beijing 100094 Peoples R China

The Atmospheric Infrared Ultraspectral Sounder (AIUS), the first high-resolution (0.02 cm(-1)) solar occultation sounder, aboard GF5, was launched in May 2018 from China. However, relevant studies about vertical profiles of atmospheric constituents based on its operational data were not conducted until half a year later. Due to an urgent need for Hin-orbit tests, the real spectra (called reference spectra hereafter) were substituted with simulated spectra calculated from the reference forward model (RFM) plus different random noises at different altitudes. In the generation process of the reference spectra for N2O, NO2, and HF species, ACE-FTS (Atmospheric Chemistry Experiment Fourier Transform Spectrometer instrument on the SCISAT satellite) level 2 products replace corresponding profiles included in the atmospheric background profiles. The optimal estimation method is employed to extract N2O, NO2, and HF profiles in this study. Comparing the retrieved results with ACE-FTS level 2 products, the relative deviations for these three species are calculated. For N2O, the average relative deviation is less than 6% at altitudes below 25 km, while larger deviations are observed in the range of 25-45 km, with the maximum being at 25%. Additionally, the difference for NO2 is less than 5% in the 20-45 km range, with a larger discrepancy found below 20 km and above 45 km;the maximum deviation reaches +/- 40%. For HF, the relative deviation is less than 6% for all tangent heights, implying satisfactory retrieval. The vertical resolution, averaging kernel, and number of degrees of freedom are used to assess the retrieval algorithm, which indicate that the retrieved information content is much more attributable to the reference spectra contribution than to the a priori profile. Finally, a large number of retrieval tests are performed for N2O, NO2, and HF in selected areas covering the Arctic region, northern middle latitude, tropics, southern middle latitude, and Antarctic region

关键词： GF5 AIUS occultation retrieval algorithm microwindow selection N2O NO2 HF

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Comparison of three retrievals of COSMIC GPS radio occultation results in the tropical upper troposphere and lower stratosphere

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EARTH PLANETS AND SPACE 2017年第1期69卷 1-15页

作者： Noersomadi Tsuda, Toshitaka Kyoto Univ RISH Kyoto Japan Natl Inst Aeronaut & Space LAPAN Ctr Atmospher Sci & Technol Bandung Indonesia ROIS Tokyo Japan

Combining geometrical optics (GO) and wave optics (WO), the COSMIC data analysis and archive center (CDAAC) retrieved two sets of dry atmosphere temperatures (T) from COSMIC GPS radio occultation (GPS-RO), which are called atmPrf2010 and atmPrf2013. In atmPrf2010, the sewing height between WO and GO varies between 10 and 20 km, but is fixed at 20 km for atmPrf2013. The height resolution of the atmPrf2010 depends on the sewing height, while the T profiles by atmPrf2013 are smoothed over 500 m. We also derived T by applying WO throughout the troposphere and the stratosphere up to a 30-km altitude, which is called rishfsi2013. The three retrievals have different characteristics in the height resolution around the tropopause. Therefore, we aim to examine a possible discrepancy in the statistical results of the cold-point tropopause (CPT) and the lapse rate tropopause (LRT) among the three datasets, conducting their inter-comparisons as well as the comparison between GPS-RO and the simultaneous radiosonde dataset. We investigate the T variations in the upper troposphere and lower stratosphere (UTLS) over the tropics from October 1, 2011, to March 31, 2012, when radiosonde soundings were conducted as the CINDY-DYNAMO 2011 campaign. The mean T profiles are consistent between atmPrf2010 and atmPrf2013, but rishfsi2013 results are colder (warmer) than the CDAAC retrievals below (above) the tropopause. The mean T difference between atmPrf2013 and atmPrf2010 is 0.17 K at the cold-point tropopause (CPT) and -0.38 K at the lapse rate tropopause (LRT). On the other hand, rishfsi2013 shows a colder T at CPT by -0.77 and -0.59 K relative to atmPrf2013 and atmPrf2010, respectively, and the warmer T by 0.60 and 0.20 Kd at LRT. During CINDY-DYNAMO, we found 134 radiosonde soundings that coincide with GPS-RO within +/- 3 h and are collocated within 200 km from GPS-RO. The mean T difference at CPT from the radiosondes is 0.32, 0.49 and -0.24 K for atmPrf2010, atmPrf2013 and rishfsi2013,

关键词： COSMIC GPS radio occultation (GPS-RO) Full spectrum inversion (FSI) Upper troposphere-lower stratosphere (UTLS) retrieval algorithm

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retrieval of precipitable water vapor using MFRSR and comparison with other multisensors over the semi-arid area of northwest China

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ATMOSPHERIC RESEARCH 2016年 172卷 83-94页

作者： Li, Xia Zhang, Lei Cao, Xianjie Quan, Jiannong Wang, Tianhe Liang, Jiening Shi, Jinsen Beijing Weather Modificat Off Beijing Peoples R China Lanzhou Univ Minist Educ Coll Atmospher Sci Key Lab Semi Arid Climate Change Lanzhou 730000 Peoples R China Beijing Key Lab Cloud Precipitat & Atmospher Wate Beijing Peoples R China

Precipitable water vapor (PWV) was retrieved using direct solar irradiance at 938 nm measured by a multifilter rotating shadowband radiometer (MFRSR) at the Semi-Arid Climate and Environment Observatory of Lanzhou University (SACOL) located in the semi-arid area of northwest China from August 2007 to June 2010. Measurement also occurred at Zhangye, China, at the Atmosphere Radiation Measurements (ARM) Program's Ancillary Facility during the dust period from April to June 2008. The line-by-line radiative transfer model (LBLRTM) code combined with the HITRAN 2004 spectral database is used to model the water vapor spectral transmittance throughout the 938-nm spectral response of MFRSR in the retrieval algorithm. Gaussian fitting is proposed to determine the daily calibration constant at the top of atmosphere for a long-term series under an obvious annual change in solar radiation. PWV retrieved by MFRSR over SACOL shows that 90% of PWV values are smaller than 1.52 cm, and PWV distribution has a seasonal variation, with maximum in summer and minimum in winter. The comparisons between MFRSR and other measurements show a better agreement between MFRSR and sunphotometer (AERONET's Cimel) PWV retrievals with relative bias of 2.9% and RMS difference of 9.1% than between MFRSR and microwave radiometer (MWR) with relative bias of 10% and RMS difference of 23% over SACOL, and an excellent agreement between MFRSR and sunphotometer with relative bias of 0.56% and RMS difference of 6.1% over Zhangye. To verify satellite PWV products over the semi-arid area of northwest China, the comparisons of PWV from MODIS and AIRS with MFRSR suggest that the agreement between satellite and MFRSR PWV retrievals is not as good as that between MFRSR and other ground-based instruments. MODIS appears to slightly underestimate PWV in a dry atmosphere but overestimate PWV in a moist atmosphere against MFRSR A method is proposed to correct MODIS PWV products. AIRS PWV products relative to MFRSR show a

关键词： MFRSR Precipitable water vapor retrieval algorithm Comparison

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A new algorithm of retrieving a petroleum substances absorption coefficient in sea water based on a remote sensing image

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Acta Oceanologica Sinica 2016年第11期35卷 97-104页

作者： HUANG Miaofen XING Xufeng SONG Qingjun LIU Yang DONG Wentong School of mathematics and computer Guangdong Ocean University Zhanjiang 524088 China National Satellite Ocean Application Service State Oceanic Administration Beijing 100081 China Petro China Exploration and Development Research Institute Beijing 100083 China

Establishing the remote sensing algorithm of retrieving the absorption coefficient of seawater petroleum substances is an efficient way to improve the accuracy of retrieving a seawater petroleum concentration using a remote sensing technology. A remote sensing reflectance is a basic physical parameter in water color remote sensing. Apply it to directly retrieve the absorption coefficient of seawater petroleum substances is of potential advantage. The absorption coefficient of waters containing petroleum [ACWCP, a_o（λ）], consists of the absorption coefficient of pure water [ACPW, a_w（λ）], plankton [ACP, a_（ph）（λ）], colored scraps [ACCS, a_（d,g）（λ）], and petroleum substance [ACPS, a_（oil）（λ）]. Among those, ACCS consists of the absorption coefficient of nonalgal particle [ACNP, a_d（λ）] and colored dissolved organic matter [ACCDOM, a_g（λ）]. For waters containing petroleum, the retrieved ACCS using the existing method is a combination absorption coefficient of ACNP,ACCDOM and ACPA [CAC, a_（d,g,oil）（λ）]. Therefore, the principle question is how to extract ACPS from *** the analysis of the three proportion tests conducted between the year of 2013 and 2015 and the corresponding remote sensing data, an algorithm of retrieving the absorption coefficient of petroleum substances is proposed based on remote sensing reflectance. First of all, ACPS and CAC are retrieved from the reflectance using the quasi-analytical algorithm（QAA）, with some parameter modified. Secondly, given the fact that the backscatter coefficient [BC, b_（bp）（555）] of total particles at 555 nm can be obtained completely from the reflectance, the relation between BC and ACNP in petroleum contaminated water can be established. As a result, ACNP can be calculated. Then, combining the remote sensing retrieving algorithm of a_g（440）, the method of achieving the spectral slope of the absorption coefficient can be established, from which ACCDOM,can be calculated. Finally, ACPS can be computed as the residual

关键词： petroleum substances in sea water remote sensing technology absorption coefficient retrieval algorithm

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A new method of satellite-based haze aerosol monitoring over the North China Plain and a comparison with MODIS Collection 6 aerosol products

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ATMOSPHERIC RESEARCH 2016年 171卷 31-40页

作者： Yan, Xing Shi, Wenzhong Luo, Nana Zhao, Wenji Hong Kong Polytech Univ Dept Land Surveying & Geoinformat ZS628 Kowloon Hong Kong Peoples R China Capital Normal Univ Coll Resource Environm & Tourism Beijing Peoples R China San Diego State Univ Dept Geog San Diego CA 92182 USA

With worldwide urbanization, hazy weather has been increasingly frequent, especially in the North China Plain. However, haze aerosol monitoring remains a challenge. In this paper, MODerate resolution Imaging Spectroradiometer (MODIS) measurements were used to develop an enhanced haze aerosol retrieval algorithm (EHARA). This method can work not only on hazy days but also on normal weather days. Based on 12-year (2002-2014) Aerosol Robotic Network (AERONET) aerosol property data, empirical single scattering albedo (SSA) and asymmetry factor (AF) values were chosen to assist haze aerosol retrieval. For validation, EHARA aerosol optical thickness (AOT) values, along with MODIS Collection 6 (C6) dark-pixel and deep blue aerosol products, were compared with AERONET data. The results show that the EHARA can achieve greater AOT spatial coverage under hazy conditions with a high accuracy (73% within error range) and work a higher resolution (1-km). Additionally, this paper presents a comprehensive discussion of the differences between and limitations of the EHARA and the MODIS C6 DT land algorithms. (C) 2015 Elsevier B.V. All rights reserved.

关键词： Haze Aerosol optical thickness retrieval algorithm Modis

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An algorithm to Retrieve Precipitation with Synthetic Aperture Radar

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Journal of Meteorological Research 2016年第3期30卷 401-411页

作者：谢亚楠刘志坤安大伟 Key Laboratory of Specialty Fiber Optics and Optical Access Networks Shanghai UniversityShanghai 200072 National Satellite Meteorological Center Beijing 100081

This paper presents a new type of rainfall retrieval algorithm,called the model-oriented statistical and Volterra *** is a combination of the model-oriented statistical（MOS） and Volterra integral equation（VIE） *** steps involved in this new algorithm can be briefly illustrated as ***,information such as the start point and width of the rain is obtained through pre-analysis of the data received by synthetic aperture radar（SAR）.Secondly,the VIE retrieval algorithm is employed over a short distance to obtain information on the shape of the ***,the rain rate can be calculated by using the MOS retrieval *** results show that the proposed algorithm is effective and simple,and can lead to time savings of nearly 50%compared with *** example of application of SAR data is also discussed,involving the retrieval of precipitation information over the South China Sea.

关键词： microwave remote sensing precipitation retrieval algorithm synthetic aperture radar

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Use of the GPM Constellation for Monitoring Heavy Precipitation Events Over the Mediterranean Region

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IEEE JOURNAL OF SELECTED TOPICS IN APPLIED EARTH OBSERVATIONS AND REMOTE SENSING 2016年第6期9卷 2733-2753页

作者： Panegrossi, Giulia Casella, Daniele Dietrich, Stefano Marra, Anna Cinzia Sano, Paolo Mugnai, Alberto Baldini, Luca Roberto, Nicoletta Adirosi, Elisa Cremonini, Roberto Bechini, Renzo Vulpiani, Gianfranco Petracca, Marco Porcu, Federico CNR ISAC I-00133 Rome Italy ARPA Piemonte Environm Protect Agcy Piedmont Reg I-10135 Turin Italy Presidency Council Ministers DPC I-00189 Rome Italy Univ Ferrara Dept Phys & Earth Sci I-40122 Ferrara Italy Univ Bologna Dept Phys & Astron I-40127 Bologna Italy

Precipitation retrievals exploiting the available passive microwave (PMW) observations by cross-track and conically scanning satellite-borne radiometers in the Global Precipitation Measurement (GPM) mission era are used to monitor and characterize heavy precipitation events that occurred during the Fall 2014 in Italy. Different physically based PMW precipitation retrieval algorithms are used: the Cloud Dynamics and Radiation Database (CDRD) and Passive microwave Neural network Precipitation retrieval (PNPR), used operationally in the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT) Satellite Application Facility on support to Operational Hydrology and Water Management (H-SAF), and the National Aeronautics and Space Administration (NASA) Goddard PROFiling algorithm (GPROF). Results show thatPMW precipitation retrievals from the GPM constellation of radiometers provide a reliable and quantitative description of the precipitation (instantaneous and on the daily scale) throughout the evolution of the precipitation systems in the Mediterranean region. The comparable relative errors among gauges, radar, and combination of radiometer overpasses legitimize the use of PMW estimates as a valuable and independent tool for monitoring precipitation. The pixel-based comparison with dual-polarization radars and raingauges indicates the ability of the different sensors to identify different precipitation areas and regimes (0.60 < POD < 0.76;0.28 < FAR < 0.45;0.42 < ETS < 0.59;-1.6 mm/h < ME < 1.1 mm/h, with values depending on the radiometer and on the precipitation product). This is particularly relevant in the presence of complex orography in proximity of coastal areas, as for the analyzed cases. The different characteristics of the radiometers (i.e., viewing geometry, spatial resolution, channel assortment) and of retrieval techniques, as well as the limitations of the ground-based reference datasets, are taken into consideration in the evaluati

关键词： Cloud Dynamics Radiation Database (CDRD) Global Precipitation Measurement (GPM) mission GPM mission passive microwave (PMW) radiometer PMW Neural network Precipitation retrieval (PNPR) precipitation radar retrieval algorithm satellite precipitation retrieval

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retrieval of sun-induced fluorescence using advanced spectral fitting methods

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REMOTE SENSING OF ENVIRONMENT 2015年 169卷 344-357页

作者： Cogliati, S. Verhoef, W. Kraft, S. Sabater, N. Alonso, L. Vicent, J. Moreno, J. Drusch, M. Colombo, R. Univ Milano Bicocca Remote Sensing Environm Dynam Lab DISAT I-20126 Milan Italy Univ Twente Fac GeoInformat Sci & Earth Observat ITC NL-7500 AE Enschede Netherlands Univ Valencia Dept Earth Phys & Thermodynam E-46100 Valencia Spain ESA ESTEC NL-2201 AZ Noordwijk Netherlands ESA ESOC D-64293 Darmstadt Germany

The FLuorescence EXplorer (FLEX) satellite mission, candidate of ESA's 8th Earth Explorer program, is explicitly optimized for detecting the sun-induced fluorescence emitted by plants. It will allow consistent measurements around the O-2-B (687 nm) and O-2-A (760 nm) bands, related to the red and far-red fluorescence emission peaks respectively, the photochemical reflectance index, and the structural-chemical state variables of the canopy. The sun-induced fluorescence signal, overlapped to the surface reflected radiance, can be accurately retrieved by employing the powerful spectral fitting technique. In this framework, a set of fluorescence retrieval algorithms optimized for FLEX are proposed in this study. Two main retrieval approaches were investigated: i) the optimization of the spectral fitting for retrieving fluorescence at the oxygen absorption bands;ii) the extension of the spectral fitting to a broader spectral window to retrieve the full fluorescence spectrum in the range from 670 to 780 nm. The accuracy of the retrieval algorithms is assessed by employing atmosphere-surface radiative transfer simulations obtained by coupling SCOPE and MODTRAN5 codes. The simulated dataset considers more realistic conditions because it includes directional effects, and the top-of-atmosphere radiance spectra are resampled to the current specifications of the FLuORescence Imaging Spectrometer (FLORIS) planned to serve as the primary instrument aboard FLEX. The retrieval accuracy obtained at the O-2-A band is strongly affected by directional effects, and better performance is found in cases where directional effects are lower. However, the best performing algorithms tested provided similar performance, the RMSE (RRMSE) is 0.044 mW m(-2) sr(-1) nm(-1) (6.2%) at the O-2-A band, 0.018 mW m(-2) sr(-1) nm(-1) (2.9%) at the O-2-B band, and 6225 mW m(-2) sr(-1) (6.4%) for the spectrally integrated fluorescence emission. The promising results achieved open new perspectives extending

关键词： Sun-induced fluorescence FLEX mission retrieval algorithm Spectral fitting methods Full fluorescence spectrum

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An assessment of arctic sea ice concentration retrieval based on “HY-2” scanning radiometer data using field observations during CHINARE-2012 and other satellite instruments

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Acta Oceanologica Sinica 2015年第3期34卷 42-50页

作者： SHI Lijiang LU Peng CHENG Bin KARVONEN Juha WANG Qimao LI Zhijun HAN Hongwei National Satellite Ocean Application Service State Oceanic Administration Laboratory of Coastal and Offshore Engineering Dalian University of Technology Finnish Meteorological Institute

A retrieval algorithm of arctic sea ice concentration （SIC） based on the brightness temperature data of “HY-2” scanning microwave radiometer has been constructed. The tie points of the brightness temperature were selected based on the statistical analysis of a polarization gradient ratio and a spectral gradient ratio over open water （OW）, first-year ice （FYI）, and multiyear ice （MYI） in arctic. The thresholds from two weather filters were used to reduce atmospheric effects over the open ocean. SIC retrievals from the “HY-2” radiom-eter data for idealized OW, FYI, and MYI agreed well with theoretical values. The 2012 annual SIC was calcu-lated and compared with two reference operational products from the National Snow and Ice Data Center （NSIDC） and the University of Bremen. The total ice-covered area yielded by the “HY-2” SIC was consistent with the results from the reference products. The assessment of SIC with the aerial photography from the fifth Chinese national arctic research expedition （CHINARE） and six synthetic aperture radar （SAR） images from the National Ice Service was carried out. The “HY-2” SIC product was 16% higher than the values de-rived from the aerial photography in the central arctic. The root-mean-square （RMS） values of SIC between “HY-2” and SAR were comparable with those between the reference products and SAR, varying from 8.57% to 12.34%. The “HY-2” SIC is a promising product that can be used for operational services.

关键词： “HY-2” scanning microwave radiometer retrieval algorithm sea ice concentration arctic

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An algorithm for In-Flight Spectral Calibration of Imaging Spectrometers

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REMOTE SENSING 2016年第12期8卷 1017-1017页

作者： Kuhlmann, Gerrit Hueni, Andreas Damm, Alexander Brunner, Dominik Swiss Fed Labs Mat Sci & Technol Empa CH-8600 Dubendorf Switzerland Univ Zurich Remote Sensing Labs CH-8057 Zurich Switzerland

Accurate spectral calibration of satellite and airborne spectrometers is essential for remote sensing applications that rely on accurate knowledge of center wavelength (CW) positions and slit function parameters (SFP). We present a new in-flight spectral calibration algorithm that retrieves CWs and SFPs across a wide spectral range by fitting a high-resolution solar spectrum and atmospheric absorbers to in-flight radiance spectra. Using a maximum a posteriori optimal estimation approach, the quality of the fit can be improved with a priori information. The algorithm was tested with synthetic spectra and applied to data from the APEX imaging spectrometer over the spectral range of 385-870 nm. CWs were retrieved with high accuracy (uncertainty <0.05 spectral pixels) from Fraunhofer lines below 550 nm and atmospheric absorbers above 650 nm. This enabled a detailed characterization of APEX's across-track spectral smile and a previously unknown along-track drift. The FWHMs of the slit function were also retrieved with good accuracy (<10% uncertainty) for synthetic spectra, while some obvious misfits appear for the APEX spectra that are likely related to radiometric calibration issues. In conclusion, our algorithm significantly improves the in-flight spectral calibration of APEX and similar spectrometers, making them better suited for the retrieval of atmospheric and surface variables relying on accurate calibration.

关键词： in-flight spectral calibration retrieval algorithm imaging spectrometer maximum a posteriori optimal estimate Airborne Prism Experiment (APEX)

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