SPIE Asia-Pacific Remote Sensing最新文献_第10页

Scattering phase function for particulates-in-water: modeling and validation 水中粒子的散射相函数:建模和验证

SPIE Asia-Pacific Remote Sensing Pub Date : 2016-05-03 DOI: 10.1117/12.2223570

S. Sahu, P. Shanmugam

{"title":"Scattering phase function for particulates-in-water: modeling and validation","authors":"S. Sahu, P. Shanmugam","doi":"10.1117/12.2223570","DOIUrl":"https://doi.org/10.1117/12.2223570","url":null,"abstract":"Scattering phase function plays a crucial role in studies and calculations based on radiative transfer theory in water as well as atmosphere. A model based on Mie theory is developed for estimating the particulates-in-water scattering phase function for forward angles (0.1° - 90°). Particle size distribution (PSD) slope (ξ) and bulk refractive index (n) are chosen as key inputs for this proposed model. The PSD slope can be estimated from the attenuation spectrum measured directly in-situ and the bulk refractive index can be calculated by an inversion model using measured backscattering ratio (BP) and PSD slope. The attenuation spectrum and backscattering ratio can be easily measured in-situ using commercially available instruments in real time. The entire range of forward angles is divided into two ranges and phase function is modeled separately in the ranges 0.1° - 5° and 5° - 90°, from numerically calculated Volume Scattering Function (VSF) using Mie theory. The division boundary is decided owing to the fact that the scattering phase functions, for different oceanic conditions, exhibit a change in slope at approximately 5°. Performance of the present model is evaluated by comparing with existing empirical and analytical models as well as measured phase functions. The proposed phase function model shows a considerable improvement upon existing models, and will have important applications in remote sensing applications and underwater studies.","PeriodicalId":165733,"journal":{"name":"SPIE Asia-Pacific Remote Sensing","volume":"196 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-05-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131966720","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 8

Assimilation of ASCAT winds using 4DVAR: an impact study 利用4DVAR同化ASCAT风:影响研究

SPIE Asia-Pacific Remote Sensing Pub Date : 2016-05-03 DOI: 10.1117/12.2223523

D. Srinivas, Indira Rani S., S. Mallick, J. George

{"title":"Assimilation of ASCAT winds using 4DVAR: an impact study","authors":"D. Srinivas, Indira Rani S., S. Mallick, J. George","doi":"10.1117/12.2223523","DOIUrl":"https://doi.org/10.1117/12.2223523","url":null,"abstract":"Sea surface wind vectors from Advanced Scatterometer (ASCAT) onboard MetOP satellites are pivotal inputs to NWP models, especially during cyclone period. NCMRWF regularly receives these winds from NOAA through ftp and routinely assimilates in the operational global models. The impact of ASCAT winds in the NCMRWF Unified Model (NCUM) assimilation and forecast system during the cyclone Chapala period from 28 October 2015 to 4 November 2015 is studied. Before assimilating, these winds are validated against in-situ observations from buoy platforms over the North Indian Ocean (NIO). It is found that the errors in the ASCAT winds are well within the limit of mission goal (<2m/s). After the successful validation, numerical experiments are designed in such a way that 10-day forecasts are generated from two different initial conditions. In the control run (CTL), ASCAT winds are removed from the Observation Processing System (OPS) and Variational Assimilation (VAR) systems of NCUM, while in the experiment run (AST) ASCAT winds are included in both OPS and VAR. Forecasts from both the runs are analysed to see the movement and intensification of the cyclonic system in due course. The results show that the experiments with ASCAT winds improved the track and intensity of the NIO cyclonic system.","PeriodicalId":165733,"journal":{"name":"SPIE Asia-Pacific Remote Sensing","volume":"230 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-05-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130974807","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Impact of EnVar hybrid assimilation using EnKF ensembles EnKF集合对EnVar混合同化的影响

SPIE Asia-Pacific Remote Sensing Pub Date : 2016-05-03 DOI: 10.1117/12.2222771

V. S. Prasad, C. Johny, J. Sodhi, E. Rajagopal

引用次数: 0

Height of warm core in very severe cyclonic storms Phailin: INSAT-3D perspective 非常强烈气旋风暴的暖核高度:INSAT-3D透视

SPIE Asia-Pacific Remote Sensing Pub Date : 2016-05-03 DOI: 10.1117/12.2223582

S. Rani, V. S. Prasad, E. Rajagopal, S. Basu

{"title":"Height of warm core in very severe cyclonic storms Phailin: INSAT-3D perspective","authors":"S. Rani, V. S. Prasad, E. Rajagopal, S. Basu","doi":"10.1117/12.2223582","DOIUrl":"https://doi.org/10.1117/12.2223582","url":null,"abstract":"Warm core is the characteristic that distinguishes tropical cyclones from its extra tropical counter parts, where the center of the cyclone is warmer than its environment. Two of the most common variables used to characterize the warm core are its strength and height. The strength is given by the magnitude of maximum perturbation temperature and the height is the level where the maximum perturbation temperature occurs. INSAT-3D, India's advanced weather satellite, is the first geostationary sounder over India and the surrounding Oceanic regions. INSAT-3D has 18 channel sounder with a resolution of 10 km to profile the atmospheric temperature and humidity. Brightness Temperatures (Tbs) from INSAT-3D sounder channels are used to analyze the warm core structure of Tropical cyclone Phailin (8–14 October 2013) over the North Indian Ocean. Only when the system becomes very severe cyclonic system, when the eye of the cyclone is clearer (fully cloud free), the sounder channel Tbs showed multiple maxima, with strong primary maximum in the middle level (600–500 mb) and the secondary maximum in the upper level (300–250 mb), unlike the conventional belief suggested warm core existence at 250 mb. Due to the high resolution of (10 km) INSAT-3D sounder channels, compared to the Micro wave channels (AMSU-A of 50 km resolution), the warm core structure below 10 km of the atmosphere is well resolved.","PeriodicalId":165733,"journal":{"name":"SPIE Asia-Pacific Remote Sensing","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-05-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123956134","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 3

A review of recent evaluation of satellite estimates sea surface salinity in the tropical Indian Ocean 最近对卫星估计热带印度洋海面盐度的评估综述

SPIE Asia-Pacific Remote Sensing Pub Date : 2016-05-03 DOI: 10.1117/12.2223571

I. Momin, A. Mitra, D. K. Mahapatra, E. Rajagopal

引用次数: 0

NASA L-SAR instrument for the NISAR (NASA-ISRO) Synthetic Aperture Radar mission 用于NISAR (NASA- isro)合成孔径雷达任务的NASA L-SAR仪器

SPIE Asia-Pacific Remote Sensing Pub Date : 2016-05-02 DOI: 10.1117/12.2228489

J. Hoffman, S. Shaffer, D. Perkovic-Martin

{"title":"NASA L-SAR instrument for the NISAR (NASA-ISRO) Synthetic Aperture Radar mission","authors":"J. Hoffman, S. Shaffer, D. Perkovic-Martin","doi":"10.1117/12.2228489","DOIUrl":"https://doi.org/10.1117/12.2228489","url":null,"abstract":"The National Aeronautics and Space Administration (NASA) in the United States and the Indian Space Research Organization (ISRO) have partnered to develop an Earth-orbiting science and applications mission that exploits synthetic aperture radar to map Earth’s surface every 12 days or less. To meet demanding coverage, sampling, and accuracy requirements, the system was designed to achieve over 240 km swath at fine resolution, and using full polarimetry where needed. To address the broad range of disciplines and scientific study areas of the mission, a dual-frequency system was conceived, at L-band (24 cm wavelength) and S-band (10 cm wavelength). To achieve these observational characteristics, a reflector-feed system is considered, whereby the feed aperture elements are individually sampled to allow a scan-on-receive (\"SweepSAR\") capability at both L-band and S-band. The instrument leverages the expanding capabilities of on-board digital processing to enable real-time calibration and digital beamforming. This paper describes the mission characteristics, current status of the L-band Synthetic Aperture Radar (L-SAR) portion of the instrument, and the technology development efforts in the United States that are reducing risk on the key radar technologies needed to ensure proper SweepSAR operations.","PeriodicalId":165733,"journal":{"name":"SPIE Asia-Pacific Remote Sensing","volume":"61 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123782474","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 9

On-orbit radiometric performance characterization of S-NPP VIIRS reflective solar bands S-NPP VIIRS反射太阳波段的在轨辐射性能表征

SPIE Asia-Pacific Remote Sensing Pub Date : 2016-05-02 DOI: 10.1117/12.2223788

S. Uprety, S. Błoński, C. Cao

{"title":"On-orbit radiometric performance characterization of S-NPP VIIRS reflective solar bands","authors":"S. Uprety, S. Błoński, C. Cao","doi":"10.1117/12.2223788","DOIUrl":"https://doi.org/10.1117/12.2223788","url":null,"abstract":"It has been nearly four years that the S-NPP was launched. In an effort to improve the VIIRS calibration, VIIRS has undergone a number of major look up table updates during this period. RSB bands such as M1 through M3 suggested higher solar diffuser degradation rate. Similarly, for higher wavelengths, even though the solar diffuser degradation is much smaller and even negligible for SWIR bands, bands such as M7 suffer from major degradation due to RTA throughput degradation. Even though the solar diffuser and mirror degradation is well characterized, the data quality needs to be independently validated to ensure that data are well within the specification. We have used on-orbit calibration/validation techniques such as extended SNOs to estimate the bias of these bands and quantify the radiometric performance since launch. Assuming MODIS as a standard reference, intercomparison was performed to analyze the VIIRS radiometric performance. It was observed that some of the VIIRS bands such as M5 and M7 suggest bias on the order of 1.5% or more for most of the time period since early launch. VIIRS bias trends keep changing over time which can be mainly correlated to calibration updates and instrument anomalies. Results on VIIRS on-orbit calibration performance and its bias since early launch will be presented during meeting to help users better understand the data quality and its impacts on broader scientific research and applications.","PeriodicalId":165733,"journal":{"name":"SPIE Asia-Pacific Remote Sensing","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125321483","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 8

S-band synthetic aperture radar on-board NISAR satellite NISAR卫星s波段合成孔径雷达

SPIE Asia-Pacific Remote Sensing Pub Date : 2016-05-02 DOI: 10.1117/12.2228077

T. Misra, R. Bhan, D. Putrevu, P. Mehrotra, Soumyabrata Chakrabarty

引用次数: 2

Instrument calibration architecture of Radar Imaging Satellite (RISAT-1) 雷达成像卫星(RISAT-1)仪器标定体系结构

SPIE Asia-Pacific Remote Sensing Pub Date : 2016-05-02 DOI: 10.1117/12.2223709

T. Misra, R. Bhan, D. Putrevu, P. Mehrotra, P. Nandy, S. Shukla, C. V. Rao, D. B. Dave, N. Desai

引用次数: 5

Dynamic MTF improvement scheme and its validation for CCD operating in TDI mode for Earth imaging applications 用于地球成像的TDI模式CCD动态MTF改进方案及其验证

SPIE Asia-Pacific Remote Sensing Pub Date : 2016-05-02 DOI: 10.1117/12.2228105

N. Dubey, A. Banerjee

引用次数: 2