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Conference on Ocean Sensing and Monitoring II

作者： Tonizzo, A. Ibrahim, A. Zhou, J. Gilerson, A. Twardowski, M. Gross, B. Moshary, F. Ahmed, S. The City College of New York (United States) WET Labs. Inc. (United States)

ISBN: (纸本)9780819481429

An acquisition system was developed to measure the above water polarized radiance. This system consists of one irradiance sensor for downwelling irradiance, one radiance sensor oriented at 40 degrees from the zenith to measure sky radiance and three radiance sensors looking down at 40 degrees from the nadir to measure above water radiance. In order to obtain the polarized radiance, polarizers with orientation of 0 degrees, 90 degrees and 45 degrees respectively were placed in front of the three radiance sensors. The whole system was installed on the bow of the boat for continuous observations of above water polarized radiance along the ship's track during a recent cruise in the NY Bight area. Water optical properties were measured by an optical package towed from a small R/V. In order to obtain the degree of polarization (DOP) of the water body, the contribution of the sky radiance must be first removed and this process has to be done for all components of the Stokes vector. Using a model employing the polarized Fresnel coefficients of the interface the polarized component of reflection is estimated from the direct measurement of sky radiance and downwelling irradiance data. These components are then subtracted from the measured values to obtain the water contribution. The DOP of the ocean body is then related to the in - water IOPs.

关键词： Remote sensing ocean water optical properties polarization retrieval algorithms

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Optical Flight Research of SAF Effects upon Contrail Generation

Optical Flight Research of SAF Effects upon Contrail Generat...

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AIAA Aviation Forum

作者： Brown, A. P. Natl Res Council Canada NRC Flight Res Lab Atmospher Res Grp U-61 Uplands Ottawa ON K1A 0R6 Canada

ISBN: (数字)9781624107047

ISBN: (纸本)9781624107047

The NRC has conducted petroleum and SAF jet fuel contrail flight research, using optical, rearwards sensing of own-ship contrail generation. Jet fuels were petroleum derived Jet A1, and SAF fuels of HEFA SPK and ATJ SPK. Measurements consisted of rear-view optical sensing of generated contrails, both sublimating and persistent, in the visual wavelength spectral range. Optical characteristics, in rear-view, were observed and are described. Contrail image brightness was analysed in comparison to sun and space-sky images, deriving albedo numbers for various rear-view orientations. Satellite retrieval algorithms were used to derive ice particle size and number density values from albedo values, which were thereafter compared for back-to-back contrails generated by Jet A1 and SPK jet fuels. Large reductions in number concentrations of approximately 90% were attributed to SPK c.f. Jet A1, whilst SPK contrail ice particles were significantly larger.

关键词： Contrails Albedo retrieval algorithms Satellites Petroleum Jet Fuel Particle Number Optical Thickness In Situ Measurements Data retrieval

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Advancing Soil Moisture Estimation with Enhanced SMAP Active/Passive Algorithm for SMAP/NISAR Combined Framework

Advancing Soil Moisture Estimation with Enhanced SMAP Active...

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2024 IEEE International Geoscience and Remote Sensing Symposium, IGARSS 2024

作者： Xu, Xiaolan Das, Narendra Yueh, Simon Entekhabi, Dara Colliander, Andreas California Institute of Technology Jet Propulsion Laboratory Pasadena United States Michigan State University Civil and Environmental Engineering LansingMI United States Massachusetts Institute of Technology Civil and Environmental Engineering CambridgeMA United States

ISBN: (纸本)9798350360325

This paper presents a refined Active and Passive (AP) algorithm from the Soil Moisture Active Passive (SMAP) mission, highlighting the progressive enhancements made to the passive algorithm over the years. The primary focus centers on the process of disaggregating coarse brightness temperature (TB) directly measured from the radiometer to attain fine-resolution TB, subsequently enabling the retrieval of soil moisture and vegetation optical depth. Throughout the operational phase of the SMAP SAR instrument, approximately 2.5 months of global SAR backscattering data were acquired simultaneously with TB data. With the imminent launch of the NASA-ISRO Synthetic Aperture Radar (NISAR) mission, the availability of continuous L-band SAR data will see a significant boost. The original SMAP SAR data encompassed four polarizations (VV, HH, HV, and VH), which prompted an examination of three disaggregation combinations: 1) The original SMAP AP algorithm, which utilizes HH, VV, and cross-polarization (X-pol) data (averaged from cross-polarizations). 2) Sole reliance on HH and X-pol data, a configuration that aligns with the capabilities of the NISAR mission, offering global coverage. 3) VV and X-pol data, aiming to provide a more comprehensive analysis. Across these three combinations, similar accuracy was observed at the core study sites, affirming the feasibility of utilizing NISAR HH/HV data exclusively for the AP algorithm. Additionally, this paper also demonstrates both the snapshot method and time-series method for parameter determination and engages in the discussion of their respective advantages and disadvantages. © 2024 IEEE.

关键词： Active and Passive NISAR retrieval algorithms SMAP soil moisture vegetation optical depth

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Ozone profile retrieval from Stratospheric Aerosol and Gas Experiment (SAGE III) limb scatter measurements

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JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES 2005年第D9期110卷

作者： Rault, DF NASA Langley Res Ctr Hampton VA 23681 USA

[ 1] The ability of SAGE III to retrieve the ozone vertical distribution within the atmosphere from limb scatter measurements is being investigated. The sunlight scattered by atmospheric gases and particulates ( aerosol and clouds) and the Earth's surface is measured and spectrally dispersed by the SAGE III high vertical resolution spectrometer. The spectral data are shown to contain sufficient information to retrieve ozone density from 10 km ( or cloud top) to 50 km at a resolution of about 1 km using ultraviolet and visible channels. Since SAGE III was not designed to operate in limb scatter mode, the radiance measurements are contaminated with significant stray light, and a method had to first be developed and implemented to deconvolve instrumental effects from the data. Furthermore, SAGE III has limited attitude determination capability, and tangent altitude registration has to be derived mostly from measured radiance profiles. Two retrieval algorithms were implemented to infer ozone profiles from measured radiance data: the first one is based on the wavelength triplet method, and the second one uses the multiple linear regression technique. Retrieved ozone profiles are shown for a series of cases and compared with available correlative data measured by ozone sondes, SAGE III in occultation mode, and OSIRIS.

关键词： satellite remote sensing limb scattering retrieval algorithms ozone

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Thermodynamic state retrieval from microwave occultation data and performance analysis based on end-to-end simulations

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JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES 2011年第D10期116卷 1D,2D,3D,4D,5D,6D,7D,8D,9D,10D,11D,12D,13D,14D,15D,16D,17D,18D,19D页

作者： Schweitzer, S. Kirchengast, G. Schwaerz, M. Fritzer, J. Gorbunov, M. E. Graz Univ Wegener Ctr Climate & Global Change A-8010 Graz Austria Graz Univ Inst Geophys Astrophys & Meteorol Inst Phys A-8010 Graz Austria Russian Acad Sci Inst Atmospher Phys Moscow Russia

Microwave occultation using centimeter- and millimeter-wave signals between low Earth orbit (LEO) satellites (LEO microwave occultation, LMO) is an advancement of GPS radio occultation (GRO) exploiting in addition to refraction also absorption of signals. Beyond the successful GRO refractivity profiling capability, which leaves a temperature-humidity ambiguity in the troposphere where moisture cannot be neglected, LMO enables joint retrieval of pressure, temperature, and humidity profiles without auxiliary background information. Here we focus on the upper troposphere/lower stratosphere and advance the LMO method in two ways: (1) we introduce a new retrieval algorithm for processing LMO excess phase and amplitude data from multiple frequencies, complementing existing GRO retrieval algorithms, and (2) we employ the algorithm in an ensemble-based end-to-end performance analysis and assess the accuracy of pressure, temperature, and humidity profiles retrieved from the LMO data. The end-to-end simulations were carried out under quasi-realistic conditions for a day of LEO-LEO occultation events, based on a high-resolution atmospheric analysis of the European Centre for Medium-Range Weather Forecasts (ECMWF) and accounting for scintillation noise from turbulence and instrumental errors. The new algorithm was found robust, fast, and versatile to adequately process LMO data under all conditions from dry and clear to moist and cloudy air as contained in the ECMWF analysis. The retrieved pressure, temperature, and humidity profiles were generally found unbiased and within target accuracy requirements, set by scientific objectives of atmosphere and climate research going to be supported by the data, of <0.2% (pressure), <0.5 K (temperature), and <10% (humidity). Extending a "minimum" LMO design with three frequencies near 22 GHz with two added frequencies near 183 GHz favorably provides humidity retrieval into the lower stratosphere but already the "minimum" design resolves th

关键词： atmospheric remote sensing microwave occultation thermodynamic state climate benchmarking retrieval algorithms end-to-end simulations

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ASSESSMENT AND DEVELOPMENT OF REMOTE SENSING BASED algorithms FOR WATER QUALITY MONITORING IN OLUSHANDJA DAM, NORTH-CENTRAL NAMIBIA

ASSESSMENT AND DEVELOPMENT OF REMOTE SENSING BASED ALGORITHM...

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作者： TAIMI SOFIA KAPALANGA University of Zimbabwe

学位级别：硕士

Olushandja Dam is amongst Namibia's inland water bodies that store and supply water to towns such as Outapi, Oshikuku and Oshakati. The dam is part of a complex water supply system that transports inter-basin water from the Kunene River Basin into Cuvelai Basin in the north-central regions of Namibia via a canal. There are potential sources of pollution along the route of the canal and around the dam which have effects on the water quality in the canal and eventually in the Olushandja Dam. Therefore, frequent and continuous monitoring of water quality is needed to allow timely decisions on the management of this critical resource. Specifically, the study sought to measure water quality at selected points in the dam and on the canal. This study used Landsat 8, 30 m resolution imagery to derive water quality parameters using retrieval algorithms. Water quality parameters included total suspended matter, turbidity, total nitrogen, nitrates, ammonia, total phosphorus and total algae counts. The study was carried out from November 2014 to June 2015. The retrieval algorithms were developed from a simple regression analysis between reflectance values of satellite images and field measurements. Statistical analyses were carried out to assess correlation between Landsat 8 predicted and field measured data. The field measurements showed that the dam and canal water is of low risk to human and is suitable for livestock watering. Turbidity levels exceeded the recommended limits set by NamWater is thus likely to cause complications in drinking water treatment as well as human and aquatic life. The study also found that all water quality parameter regression algorithms had high correlation coefficients (R 2 ) which was between 0.980-0.999. Therefore, the study concludes that the developed regression algorithms are best fit to predict water quality parameters from satellite data. Remote sensing is therefore recommended for frequent and continuous monitoring of Olushandja Dam as it

关键词： Olushandja Dam Landsat Remote Sensing retrieval algorithms Water Quality

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Validation of Carbon Trace Gas Profile retrievals from the NOAA-Unique Combined Atmospheric Processing System for the Cross-Track Infrared Sounder

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REMOTE SENSING 2020年第19期12卷 3245-3245页

作者： Nalli, Nicholas R. Tan, Changyi Warner, Juying Divakarla, Murty Gambacorta, Antonia Wilson, Michael Zhu, Tong Wang, Tianyuan Wei, Zigang Pryor, Ken Kalluri, Satya Zhou, Lihang Sweeney, Colm Baier, Bianca C. McKain, Kathryn Wunch, Debra Deutscher, Nicholas M. Hase, Frank Iraci, Laura T. Kivi, Rigel Morino, Isamu Notholt, Justus Ohyama, Hirofumi Pollard, David E. Te, Yao Velazco, Voltaire A. Warneke, Thorsten Sussmann, Ralf Rettinger, Markus IMSG Inc NESDIS Ctr Satellite Applicat & Res STAR NOAA College Pk MD 20740 USA UMD Dept Atmospher & Ocean Sci College Pk MD 20740 USA NASA Goddard Space Flight Ctr Climate & Radiat Lab Greenbelt MD 20771 USA NOAA NESDIS STAR College Pk MD 20740 USA NOAA JPSS Program Off Lanham MD 20706 USA NOAA Global Monitoring Lab GML Boulder CO 80305 USA Univ Colorado Cooperat Inst Res Environm Sci Boulder CO 80305 USA Univ Toronto Dept Phys Toronto ON M5S 1A7 Canada Univ Wollongong Ctr Atmospher Chem Sch Earth Atmospher & Life Sci Wollongong NSW 2522 Australia Karlsruhe Inst Technol Inst Meteorol & Climate Res IMK ASF D-76137 Karlsruhe Germany NASA Ames Res Ctr Atmospher Sci Branch Mail Stop 245-5 Moffett Field CA 94035 USA Finnish Meteorol Inst Space & Earth Observat Ctr Tahtelantie 62 Sodankyla 99600 Finland Natl Inst Environm Studies NIES Satellite Remote Sensing Sect Onogawa 16-2 Tsukuba Ibaraki 3058506 Japan Natl Inst Environm Studies NIES Satellite Observat Ctr Onogawa 16-2 Tsukuba Ibaraki 3058506 Japan Univ Bremen Inst Environm Phys D-28195 Bremen Germany Natl Inst Water & Atmospher Res Ltd Hamilton 3216 New Zealand PSL Univ Lab Etud Rayonnement & Mat Astrophys & Atmosphere Observ Paris Sorbonne UnivCNRS F-75005 Paris France Karlsruhe Inst Technol IMK IFU D-82467 Garmisch Partenkirchen Germany

This paper provides an overview of the validation of National Oceanic and Atmospheric Administration (NOAA) operational retrievals of atmospheric carbon trace gas profiles, specifically carbon monoxide (CO), methane (CH4) and carbon dioxide (CO2), from the NOAA-Unique Combined Atmospheric Processing System (NUCAPS), a NOAA enterprise algorithm that retrieves atmospheric profile environmental data records (EDRs) under global non-precipitating (clear to partly cloudy) conditions. Vertical information about atmospheric trace gases is obtained from the Cross-track Infrared Sounder (CrIS), an infrared Fourier transform spectrometer that measures high resolution Earth radiance spectra from NOAA operational low earth orbit (LEO) satellites, including the Suomi National Polar-orbiting Partnership (SNPP) and follow-on Joint Polar Satellite System (JPSS) series beginning with NOAA-20. The NUCAPS CO, CH4, and CO2 profile EDRs are rigorously validated in this paper using well-established independent truth datasets, namely total column data from ground-based Total Carbon Column Observing Network (TCCON) sites, and in situ vertical profile data obtained from aircraft and balloon platforms via the NASA Atmospheric Tomography (ATom) mission and NOAA AirCore sampler, respectively. Statistical analyses using these datasets demonstrate that the NUCAPS carbon gas profile EDRs generally meet JPSS Level 1 global performance requirements, with the absolute accuracy and precision of CO 5% and 15%, respectively, in layers where CrIS has vertical sensitivity;CH4 and CO2 product accuracies are both found to be within +/- 1%, with precisions of approximate to 1.5% and <0.5%, respectively, throughout the tropospheric column.

关键词： satellite cal val error analysis greenhouse gases carbon monoxide methane carbon dioxide trace gas remote sensing retrieval algorithms satellite applications

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Monitoring and spatial traceability of river water quality using Sentinel-2 satellite images

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SCIENCE OF THE TOTAL ENVIRONMENT 2023年第1期894卷 164862页

作者： Zhang, Yingyin He, Xianqiang Lian, Gang Bai, Yan Yang, Ying Gong, Fang Wang, Difeng Zhang, Zili Li, Teng Jin, Xuchen Zhejiang Univ Ocean Coll Zhoushan 316021 Peoples R China Minist Nat Resources Inst Oceanog 2 State Key Lab Satellite Ocean Environm Dynam Hangzhou 310012 Peoples R China Zhejiang Ecol & Environm Monitoring Ctr Zhejiang Key Lab Ecol & Environm Monitoring Hangzhou 310012 Peoples R China Donghai Lab Zhoushan 316021 Peoples R China Shanghai Jiao Tong Univ Sch Oceanog Shanghai 200030 Peoples R China Guangdong Lab Guangzhou South Marine Sci & Engn Guangzhou 510000 Guangdong Peoples R China

Due to limited monitoring stations along rivers, it is difficult to trace the specific locations of high pollution areas along the whole river by traditionally in situ measurement. High-spatiotemporal-resolution Sentinel-2 satellite images make it possible to routinely monitor and trace the spatial distributions of river water quality if reliable retrieval algorithms are available. This study took seven major rivers (Qiantang River (QTR), Cao'e River (CEJ), Yongjiang River (YJ), Jiaojiang River (JJ), Oujiang River (OJ), Feiyun River (FYR), and Aojiang River (AJ)) in Zhejiang Province, China, as examples to illustrate the spatial traceability of river water quality parameters (permanganate index (CODMn), total phosphorus (TP), and total nitrogen (TN)) from Sentinel-2 satellite images. The regional retrieval models established for these parameters (CODMn, TP and TN) provided correlation coefficients (R) of 0.68, 0.82, and 0.7, respectively. Based on these models, time-series CODMn, TP, and TN products were obtained for the seven rivers from 2016 to 2021 from Sentinel-2 satellite images, and the results show that the CODMn, TP and TN were high downstream and low upstream;exceptions the CEJ, which was slightly higher in the middle reach than other reaches, and the TN in YJ, which was higher upstream than downstream. The downstream reaches were the main areas suffering from relatively high values in most seasons. Except for the springtime TN level in CEJ, the high value areas were located along the middle reaches. In summer and autumn, the high TN areas in JJ, OJ, and AJ were located along the middle and lower reaches, and the TN in YJ was highest in the upstream. More importantly, this study revealed that the specific locations of high pollution areas along rivers can be effectively traced using Sentinel-2 satellite images, which would be helpful for precise water quality control of rivers.

关键词： River water quality Spatial traceability Satellite remote sensing Sentinel-2 images retrieval algorithms

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User Intent in Multimedia Search: A Survey of the State of the Art and Future Challenges

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ACM COMPUTING SURVEYS 2016年第2期49卷 36-36页

作者： Kofler, Christoph Larson, Martha Hanjalic, Alan Bloomberg LP Search & Discoverabil 731 Lexington Ave New York NY 10022 USA Delft Univ Technol Fac Elect Engn Math & Comp Sci Dept Intelligent Syst Multimedia Comp Grp Mekelweg 4 NL-2628 CD Delft Netherlands

Today'smultimedia search engines are expected to respond to queries reflecting a wide variety of information needs from users with different goals. The topical dimension ("what"the user is searching for) of these information needs is well studied;however, the intent dimension ("why"the user is searching) has received relatively less attention. Specifically, intent is the "immediate reason, purpose, or goal"that motivates a user to query a search engine. We present a thorough survey of multimedia information retrieval research directed at the problem of enabling search engines to respond to user intent. The survey begins by defining intent, including a differentiation from related, often-confused concepts. It then presents the key conceptual models of search intent. The core is an overview of intent-aware approaches that operate at each stage of the multimedia search engine pipeline (i.e., indexing, query processing, ranking). We discuss intent in conventional text-based search wherever it provides insight into multimedia search intent or intent-aware approaches. Finally, we identify and discuss the most important future challenges for intent-aware multimedia search engines. Facing these challenges will allow multimedia information retrieval to recognize and respond to user intent and, as a result, fully satisfy the information needs of users.

关键词： algorithms Design Human Factors Theory User intent multimedia information retrieval multimedia search multimedia indexing retrieval algorithms

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Dual-Wavelength Polarimetric Lidar Observations of the Volcanic Ash Cloud Produced during the 2016 Etna Eruption

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REMOTE SENSING 2021年第9期13卷 1728-1728页

作者： Mereu, Luigi Scollo, Simona Boselli, Antonella Leto, Giuseppe Zanmar Sanchez, Ricardo Bonadonna, Costanza Marzano, Frank Silvio Sapienza Univ Rome Dept Informat Engn I-00184 Rome Italy Ctr Excellence CETEMPS I-67100 Laquila Italy Ist Nazl Geofis & Vulcanol Osservatorio Etneo I-95125 Catania Italy CNR IMAA I-85050 Potenza Italy INAF Osservatorio Astrofis I-95123 Catania Italy Univ Geneva Dept Earth Sci CH-1205 Geneva Switzerland

Lidar observations are very useful to analyse dispersed volcanic clouds in the troposphere mainly because of their high range resolution, providing morphological as well as microphysical (size and mass) properties. In this work, we analyse the volcanic cloud of 18 May 2016 at Mt. Etna, in Italy, retrieved by polarimetric dual-wavelength Lidar measurements. We use the AMPLE (Aerosol Multi-Wavelength Polarization Lidar Experiment) system, located in Catania, about 25 km from the Etna summit craters, pointing at a thin volcanic cloud layer, clearly visible and dispersed from the summit craters at the altitude between 2 and 4 km and 6 and 7 km above the sea level. Both the backscattering and linear depolarization profiles at 355 nm (UV, ultraviolet) and 532 nm (VIS, visible) wavelengths, respectively, were obtained using different angles at 20 degrees, 30 degrees, 40 degrees and 90 degrees. The proposed approach inverts the Lidar measurements with a physically based inversion methodology named Volcanic Ash Lidar retrieval (VALR), based on Maximum-Likelihood (ML). VALRML can provide estimates of volcanic ash mean size and mass concentration at a resolution of few tens of meters. We also compared those results with two methods: Single-variate Regression (SR) and Multi-variate Regression (MR). SR uses the backscattering coefficient or backscattering and depolarization coefficients of one wavelength (UV or VIS in our cases). The MR method uses the backscattering coefficient of both wavelengths (UV and VIS). In absence of in situ airborne validation data, the discrepancy among the different retrieval techniques is estimated with respect to the VALR ML algorithm. The VALR ML analysis provides ash concentrations between about 0.1 mu g/m(3) and 1 mg/m(3) and particle mean sizes of 0.1 mu m and 6 mu m, respectively. Results show that, for the SR method differences are less than <10%, using the backscattering coefficient only and backscattering and depolarization coefficients. Mo

关键词： Lidar measurements retrieval algorithms dual wavelength scanning light detection volcanic ash size and concentration

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