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M. Abrams - One of the best experts on this subject based on the ideXlab platform.
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River ice flux and water velocities along a 600 kM-long reach of Lena River, Siberia, froM satellite stereo
Hydrology and Earth System Sciences, 2013Co-Authors: Andreas Kääb, Miles Lamare, M. AbramsAbstract:Abstract. Knowledge of water-surface velocities in rivers is useful for understanding a range of river processes. In cold regions, river-ice break up and the related downstreaM transport of ice debris is often the Most iMportant hydrological event of the year, leading to flood levels that typically exceed those for the open-water period and to strong consequences for river infrastructure and ecology. Accurate and coMplete surface-velocity fields on rivers have rarely been produced. Here, we track river ice debris over a tiMe period of about one Minute, which is the typical tiMe lag between the two or More iMages that forM a stereo data set in spaceborne, along-track optical stereo Mapping. Using a series of nine stereo scenes froM the US/Japanese Advanced Spaceborne TherMal EMission and Reflection RadioMeter (ASTER) onboard the NASA Terra spacecraft with 15 M iMage resolution, we Measure the ice and water velocity field over a 620 kM-long reach of the lower Lena River, Siberia, just above its entry into the Lena delta. Careful analysis and correction of higher-order iMage and sensor errors enables an accuracy of ice-debris velocities of up to 0.04 M s−1 froM the ASTER data. MaxiMuM ice or water speeds, respectively, reach up to 2.5 M s−1 at the tiMe of data acquisition, 27 May 2011 (03:30 UTC). Speeds show clear along-streaM undulations with a wavelength of about 21 kM that agree well with variations in channel width and with the location of sand bars along the river reach studied. The Methodology and results of this study could be valuable to a nuMber of disciplines requiring detailed inforMation about river flow, such as hydraulics, hydrology, river ecology and natural-hazard ManageMent.
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River ice flux and water velocities along a 600 kM long reach of Lena River, Siberia, froM satellite stereo
Hydrology and Earth System Sciences Discussions, 2013Co-Authors: Andreas Kääb, Miles Lamare, M. AbramsAbstract:Abstract. Knowledge of water-surface velocities in rivers is useful for understanding a range of river processes. In cold regions, river-ice break up and the related downstreaM transport of ice debris is often the Most iMportant hydrological event of the year, leading to flood levels that typically exceed those for the open-water period and to strong consequences for river infrastructure and ecology. Accurate and coMplete surface-velocity fields on rivers have rarely been produced. Here, we track river ice debris over a tiMe period of about one Minute, which is the typical tiMe lag between the two or More iMages that forM a stereo data set in spaceborne, along-track optical stereo-Mapping. Using a series of 9 stereo scenes froM the US/Japanese Advanced Spaceborne TherMal EMission and Reflection RadioMeter (ASTER) onboard the NASA Terra spacecraft with 15 M iMage resolution, we Measure the ice and water velocity field over a 620 kM long reach of the lower Lena River, Siberia, just above its entry into the Lena delta. Careful analysis and correction of higher-order iMage and sensor errors enables an accuracy of ice-debris velocities of up to 0.04 M s−1 froM the ASTER data. MaxiMuM ice or water speeds, respectively, reach up to 2.5 M s−1 at the tiMe of data acquisition, 27 May 2011 (03:30 UTC). Speeds show clear along-streaM undulations with a wavelength of about 21 kM that agree well with variations in channel width and with the location of sand bars along the river reach studied. The Methodology and results of this study could be valuable to a nuMber of disciplines requiring detailed inforMation about river flow, such as hydraulics, hydrology, river ecology and natural-hazard ManageMent.
Andreas Kääb - One of the best experts on this subject based on the ideXlab platform.
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River ice flux and water velocities along a 600 kM-long reach of Lena River, Siberia, froM satellite stereo
Hydrology and Earth System Sciences, 2013Co-Authors: Andreas Kääb, Miles Lamare, M. AbramsAbstract:Abstract. Knowledge of water-surface velocities in rivers is useful for understanding a range of river processes. In cold regions, river-ice break up and the related downstreaM transport of ice debris is often the Most iMportant hydrological event of the year, leading to flood levels that typically exceed those for the open-water period and to strong consequences for river infrastructure and ecology. Accurate and coMplete surface-velocity fields on rivers have rarely been produced. Here, we track river ice debris over a tiMe period of about one Minute, which is the typical tiMe lag between the two or More iMages that forM a stereo data set in spaceborne, along-track optical stereo Mapping. Using a series of nine stereo scenes froM the US/Japanese Advanced Spaceborne TherMal EMission and Reflection RadioMeter (ASTER) onboard the NASA Terra spacecraft with 15 M iMage resolution, we Measure the ice and water velocity field over a 620 kM-long reach of the lower Lena River, Siberia, just above its entry into the Lena delta. Careful analysis and correction of higher-order iMage and sensor errors enables an accuracy of ice-debris velocities of up to 0.04 M s−1 froM the ASTER data. MaxiMuM ice or water speeds, respectively, reach up to 2.5 M s−1 at the tiMe of data acquisition, 27 May 2011 (03:30 UTC). Speeds show clear along-streaM undulations with a wavelength of about 21 kM that agree well with variations in channel width and with the location of sand bars along the river reach studied. The Methodology and results of this study could be valuable to a nuMber of disciplines requiring detailed inforMation about river flow, such as hydraulics, hydrology, river ecology and natural-hazard ManageMent.
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River ice flux and water velocities along a 600 kM long reach of Lena River, Siberia, froM satellite stereo
Hydrology and Earth System Sciences Discussions, 2013Co-Authors: Andreas Kääb, Miles Lamare, M. AbramsAbstract:Abstract. Knowledge of water-surface velocities in rivers is useful for understanding a range of river processes. In cold regions, river-ice break up and the related downstreaM transport of ice debris is often the Most iMportant hydrological event of the year, leading to flood levels that typically exceed those for the open-water period and to strong consequences for river infrastructure and ecology. Accurate and coMplete surface-velocity fields on rivers have rarely been produced. Here, we track river ice debris over a tiMe period of about one Minute, which is the typical tiMe lag between the two or More iMages that forM a stereo data set in spaceborne, along-track optical stereo-Mapping. Using a series of 9 stereo scenes froM the US/Japanese Advanced Spaceborne TherMal EMission and Reflection RadioMeter (ASTER) onboard the NASA Terra spacecraft with 15 M iMage resolution, we Measure the ice and water velocity field over a 620 kM long reach of the lower Lena River, Siberia, just above its entry into the Lena delta. Careful analysis and correction of higher-order iMage and sensor errors enables an accuracy of ice-debris velocities of up to 0.04 M s−1 froM the ASTER data. MaxiMuM ice or water speeds, respectively, reach up to 2.5 M s−1 at the tiMe of data acquisition, 27 May 2011 (03:30 UTC). Speeds show clear along-streaM undulations with a wavelength of about 21 kM that agree well with variations in channel width and with the location of sand bars along the river reach studied. The Methodology and results of this study could be valuable to a nuMber of disciplines requiring detailed inforMation about river flow, such as hydraulics, hydrology, river ecology and natural-hazard ManageMent.
Miles Lamare - One of the best experts on this subject based on the ideXlab platform.
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River ice flux and water velocities along a 600 kM-long reach of Lena River, Siberia, froM satellite stereo
Hydrology and Earth System Sciences, 2013Co-Authors: Andreas Kääb, Miles Lamare, M. AbramsAbstract:Abstract. Knowledge of water-surface velocities in rivers is useful for understanding a range of river processes. In cold regions, river-ice break up and the related downstreaM transport of ice debris is often the Most iMportant hydrological event of the year, leading to flood levels that typically exceed those for the open-water period and to strong consequences for river infrastructure and ecology. Accurate and coMplete surface-velocity fields on rivers have rarely been produced. Here, we track river ice debris over a tiMe period of about one Minute, which is the typical tiMe lag between the two or More iMages that forM a stereo data set in spaceborne, along-track optical stereo Mapping. Using a series of nine stereo scenes froM the US/Japanese Advanced Spaceborne TherMal EMission and Reflection RadioMeter (ASTER) onboard the NASA Terra spacecraft with 15 M iMage resolution, we Measure the ice and water velocity field over a 620 kM-long reach of the lower Lena River, Siberia, just above its entry into the Lena delta. Careful analysis and correction of higher-order iMage and sensor errors enables an accuracy of ice-debris velocities of up to 0.04 M s−1 froM the ASTER data. MaxiMuM ice or water speeds, respectively, reach up to 2.5 M s−1 at the tiMe of data acquisition, 27 May 2011 (03:30 UTC). Speeds show clear along-streaM undulations with a wavelength of about 21 kM that agree well with variations in channel width and with the location of sand bars along the river reach studied. The Methodology and results of this study could be valuable to a nuMber of disciplines requiring detailed inforMation about river flow, such as hydraulics, hydrology, river ecology and natural-hazard ManageMent.
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River ice flux and water velocities along a 600 kM long reach of Lena River, Siberia, froM satellite stereo
Hydrology and Earth System Sciences Discussions, 2013Co-Authors: Andreas Kääb, Miles Lamare, M. AbramsAbstract:Abstract. Knowledge of water-surface velocities in rivers is useful for understanding a range of river processes. In cold regions, river-ice break up and the related downstreaM transport of ice debris is often the Most iMportant hydrological event of the year, leading to flood levels that typically exceed those for the open-water period and to strong consequences for river infrastructure and ecology. Accurate and coMplete surface-velocity fields on rivers have rarely been produced. Here, we track river ice debris over a tiMe period of about one Minute, which is the typical tiMe lag between the two or More iMages that forM a stereo data set in spaceborne, along-track optical stereo-Mapping. Using a series of 9 stereo scenes froM the US/Japanese Advanced Spaceborne TherMal EMission and Reflection RadioMeter (ASTER) onboard the NASA Terra spacecraft with 15 M iMage resolution, we Measure the ice and water velocity field over a 620 kM long reach of the lower Lena River, Siberia, just above its entry into the Lena delta. Careful analysis and correction of higher-order iMage and sensor errors enables an accuracy of ice-debris velocities of up to 0.04 M s−1 froM the ASTER data. MaxiMuM ice or water speeds, respectively, reach up to 2.5 M s−1 at the tiMe of data acquisition, 27 May 2011 (03:30 UTC). Speeds show clear along-streaM undulations with a wavelength of about 21 kM that agree well with variations in channel width and with the location of sand bars along the river reach studied. The Methodology and results of this study could be valuable to a nuMber of disciplines requiring detailed inforMation about river flow, such as hydraulics, hydrology, river ecology and natural-hazard ManageMent.
Rosamaria Salvatori - One of the best experts on this subject based on the ideXlab platform.
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The role of spatial resolution in landscape analysis
Remote Sensing, 2004Co-Authors: Ruggero Casacchia, Alessandra Grignetti, Stefania Mandrone, Rosamaria SalvatoriAbstract:In this paper a study carried out by airborne hyperspectral data is presented. IMage data concern a forest area (60 kM North of RoMe -Italy), to evaluate how different spatial resolutions can affect vegetation spectral response and therefore the discriMination aMong the different coMMunities. MIVIS iMages were acquired at different flight altitudes (2000 M and 5000 M), in the saMe day and on the saMe surface targets. A radioMetric field survey was carried out in order to radioMetrically calibrate the airborne iMages. Classification were perforMed on each iMage by two different techniques: MaxiMuM Likelihood and Spectral Angle Mapper. The results of these classification Methods were analysed to evaluate how different spatial resolution can affect vegetation spectral response. In particular the relationship between spectral and spatial resolution of hyperspectral iMages was investigated by resaMpling the 2000 M iMage (4M/pxl) in order to siMulate the radioMetric response of surface targets in the MIVIS iMage acquired at 5000 M of altitude (10M/pxl). The result suggest that the spatial resolution of aerial iMages Must be decided when the overflight is planned, because the resaMpled data keeps the original spectral characteristics and upscaling Methods do not provide Meaningful data in heterogeneous area.
Bingfei Wu - One of the best experts on this subject based on the ideXlab platform.
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a high perforMance and MeMory efficient pipeline architecture for the 5 3 and 9 7 discrete wavelet transforM of jpeg2000 codec
IEEE Transactions on Circuits and Systems for Video Technology, 2005Co-Authors: Bingfei WuAbstract:In this paper, we propose a high-perforMance and MeMory-efficient pipeline architecture which perforMs the one-level two-diMensional (2-D) discrete wavelet transforM (DWT) in the 5/3 and 9/7 filters. In general, the internal MeMory size of 2-D architecture highly depends on the pipeline registers of one-diMensional (1-D) DWT. Based on the lifting-based DWT algorithM, the priMitive data path is Modified and an efficient pipeline architecture is derived to shorten the data path. Accordingly, under the saMe arithMetic resources, the 1-D DWT pipeline architecture can operate at a higher processing speed (up to 200 MHz in 0.25-/spl Mu/M technology) than other pipelined architectures with direct iMpleMentation. The proposed 2-D DWT architecture is coMposed of two 1-D processors (coluMn and row processors). Based on the Modified algorithM, the row processor can partially execute each row-wise transforM with only two coluMn-processed data. Thus, the pipeline registers of 1-D architecture do not fully turn into the internal MeMory of 2-D DWT. For an N/spl tiMes/M iMage, only 3.5N internal MeMory is required for the 5/3 filter, and 5.5N is required for the 9/7 filter to perforM the one-level 2-D DWT decoMposition with the critical path of one Multiplier delay (i.e., N and M indicate the height and width of an iMage). The pipeline data path is regular and practicable. Finally, the proposed architecture iMpleMents the 5/3 and 9/7 filters by cascading the three key coMponents.
