The Experts below are selected from a list of 303 Experts worldwide ranked by ideXlab platform
Svenerik Gryning - One of the best experts on this subject based on the ideXlab platform.
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comparison of the atmospheric stability and Wind Profiles at two Wind farm sites over a long marine fetch in the north sea
Wind Energy, 2011Co-Authors: Ameya Sathe, Svenerik Gryning, Alfredo PenaAbstract:A comparison of the atmospheric stability and Wind Profiles using data from meteorological masts located near two Wind farm sites in the North Sea, Egmond aan Zee (up to 116 m) in the Dutch North Sea and Horns Rev (HR; up to 45 m) in the Danish North Sea, is presented. Only the measurements that represent long marine fetch are considered. It was observed that within a long marine fetch, the conditions in the North Sea are dominated by unstable [41% at Egmond aan Zee Offshore Wind Farm (OWEZ) and 33% at HR] and near-neutral conditions (49% at OWEZ and 47% at HR), and stable conditions (10% at OWEZ and 20% at HR) occur for a limited period. The logarithmic Wind Profiles with the surface-layer stability correction terms and Charnock's roughness model agree with the measurements at both sites in all unstable and near-neutral conditions. An extended Wind profile valid for the entire boundary layer is compared with the measurements. For the tall mast at Egmond aan Zee, it was found that for stable conditions, the scaling of the Wind Profiles with respect to boundary-layer height is necessary, and the addition of another length scale parameter is preferred. At the lower mast at HR, the effect was not noticeable. Copyright © 2011 John Wiley & Sons, Ltd.
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long term mean Wind Profiles based on similarity theory
Boundary-Layer Meteorology, 2010Co-Authors: Mark C Kelly, Svenerik GryningAbstract:We provide general forms for long-term mean Wind Profiles from similarity-based Wind Profiles, beginning with a probabilistic adaptation of Monin–Obukhov similarity theory. We develop an analytical formulation for the stability distributions prevailing in the atmospheric surface layer, which in turn facilitates the derivation of a long-term mean Wind profile based on Monin–Obukhov similarity theory. The modelled stability distributions exhibit good agreement with measurements from sites having different local conditions. The long-term Wind profile formulation is further extended to include the influence of the depth of the atmospheric boundary layer (h), which becomes relevant for heights above h/3, and the resultant long-term ‘tall’ profile form also matches observations.
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charnock s roughness length model and non dimensional Wind Profiles over the sea
Boundary-Layer Meteorology, 2008Co-Authors: Alfredo Pena, Svenerik GryningAbstract:An analysis tool for the study of Wind speed Profiles over the water has been developed. The Profiles are analysed using a modified dimensionless Wind speed and dimensionless height, assuming that the sea surface roughness can be predicted by Charnock’s roughness length model. In this form, the roughness dependency on Wind speed is extracted and the variations on the Wind profile are due solely to atmospheric stability. The use of the Charnock’s non-dimensional Wind profile is illustrated using data collected from a meteorological mast installed in the Danish North Sea. The best fit with the observed mean non-dimensional Wind profile under neutral atmospheric conditions is found using a value of 1.2 × 10−2 for Charnock’s parameter. The stability correction on the neutral Wind profile suggested by the Businger-Dyer relations was found to perform well over the sea.
Alfredo Pena - One of the best experts on this subject based on the ideXlab platform.
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comparison of the atmospheric stability and Wind Profiles at two Wind farm sites over a long marine fetch in the north sea
Wind Energy, 2011Co-Authors: Ameya Sathe, Svenerik Gryning, Alfredo PenaAbstract:A comparison of the atmospheric stability and Wind Profiles using data from meteorological masts located near two Wind farm sites in the North Sea, Egmond aan Zee (up to 116 m) in the Dutch North Sea and Horns Rev (HR; up to 45 m) in the Danish North Sea, is presented. Only the measurements that represent long marine fetch are considered. It was observed that within a long marine fetch, the conditions in the North Sea are dominated by unstable [41% at Egmond aan Zee Offshore Wind Farm (OWEZ) and 33% at HR] and near-neutral conditions (49% at OWEZ and 47% at HR), and stable conditions (10% at OWEZ and 20% at HR) occur for a limited period. The logarithmic Wind Profiles with the surface-layer stability correction terms and Charnock's roughness model agree with the measurements at both sites in all unstable and near-neutral conditions. An extended Wind profile valid for the entire boundary layer is compared with the measurements. For the tall mast at Egmond aan Zee, it was found that for stable conditions, the scaling of the Wind Profiles with respect to boundary-layer height is necessary, and the addition of another length scale parameter is preferred. At the lower mast at HR, the effect was not noticeable. Copyright © 2011 John Wiley & Sons, Ltd.
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charnock s roughness length model and non dimensional Wind Profiles over the sea
Boundary-Layer Meteorology, 2008Co-Authors: Alfredo Pena, Svenerik GryningAbstract:An analysis tool for the study of Wind speed Profiles over the water has been developed. The Profiles are analysed using a modified dimensionless Wind speed and dimensionless height, assuming that the sea surface roughness can be predicted by Charnock’s roughness length model. In this form, the roughness dependency on Wind speed is extracted and the variations on the Wind profile are due solely to atmospheric stability. The use of the Charnock’s non-dimensional Wind profile is illustrated using data collected from a meteorological mast installed in the Danish North Sea. The best fit with the observed mean non-dimensional Wind profile under neutral atmospheric conditions is found using a value of 1.2 × 10−2 for Charnock’s parameter. The stability correction on the neutral Wind profile suggested by the Businger-Dyer relations was found to perform well over the sea.
Carsten Hirt - One of the best experts on this subject based on the ideXlab platform.
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double edge molecular measurement of lidar Wind Profiles at 355 nm
Optics Letters, 2000Co-Authors: C. Flesia, Laurence C Korb, Carsten HirtAbstract:We built a direct-detection Doppler lidar based on the double-edge molecular technique and made the what we believe to be the first molecular-based Wind measurements using the eye-safe 355-nm wavelength. Three etalon bandpasses are obtained with step etalons on a single pair of etalon plates. We eliminate long-term frequency drift of the laser and the capacitively stabilized etalon by locking the etalon to the laser frequency. We use a low-angle design to avoid polarization effects. Wind measurements of 1–2‐m/s accuracy are obtained to 10-km altitude with 5 mJ of laser energy, a 750-s integration, and a 25-cm telescope. Good agreement is obtained between lidar and rawinsonde measurements.
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Double-edge molecular measurement of lidar Wind Profiles at 355 nm
Optics Letters, 2000Co-Authors: C. Flesia, C. Korb, Carsten HirtAbstract:We have developed a transportable container based direct detection Doppler lidar based on the double-edge molecular technique. The pulsed solid state system was built at the University of Geneva. It was used to make range resolved measurements of the atmospheric Wind field as part of the VALID campaign at the Observatoire de Haute Provence in Provence, France in July 1999. Comparison of our lidar Wind measurements, which were analyzed without knowledge of the results of rawinsonde measurements made under the supervision of ESA, show good agreement with these rawinsondes. These are the first Doppler lidar field measurements made with an eyesafe direct detection molecular-based system at 355 nm and serve as a demonstrator for future spaceborne direct detection Wind systems such as the Atmospheric Dynamics mission. Winds are an important contributor to sea surface temperature measurements made with the Tropical Rainfall Measuring Mission (TRMM) and also affect the TRMM rainfall estimates.
C. Flesia - One of the best experts on this subject based on the ideXlab platform.
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double edge molecular measurement of lidar Wind Profiles at 355 nm
Optics Letters, 2000Co-Authors: C. Flesia, Laurence C Korb, Carsten HirtAbstract:We built a direct-detection Doppler lidar based on the double-edge molecular technique and made the what we believe to be the first molecular-based Wind measurements using the eye-safe 355-nm wavelength. Three etalon bandpasses are obtained with step etalons on a single pair of etalon plates. We eliminate long-term frequency drift of the laser and the capacitively stabilized etalon by locking the etalon to the laser frequency. We use a low-angle design to avoid polarization effects. Wind measurements of 1–2‐m/s accuracy are obtained to 10-km altitude with 5 mJ of laser energy, a 750-s integration, and a 25-cm telescope. Good agreement is obtained between lidar and rawinsonde measurements.
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Double-edge molecular measurement of lidar Wind Profiles at 355 nm
Optics Letters, 2000Co-Authors: C. Flesia, C. Korb, Carsten HirtAbstract:We have developed a transportable container based direct detection Doppler lidar based on the double-edge molecular technique. The pulsed solid state system was built at the University of Geneva. It was used to make range resolved measurements of the atmospheric Wind field as part of the VALID campaign at the Observatoire de Haute Provence in Provence, France in July 1999. Comparison of our lidar Wind measurements, which were analyzed without knowledge of the results of rawinsonde measurements made under the supervision of ESA, show good agreement with these rawinsondes. These are the first Doppler lidar field measurements made with an eyesafe direct detection molecular-based system at 355 nm and serve as a demonstrator for future spaceborne direct detection Wind systems such as the Atmospheric Dynamics mission. Winds are an important contributor to sea surface temperature measurements made with the Tropical Rainfall Measuring Mission (TRMM) and also affect the TRMM rainfall estimates.
G J Komar - One of the best experts on this subject based on the ideXlab platform.
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Preparing for future EO innovations: The NASA Earth Science Technology program
Lasers and Electro-Optics (CLEO) 2012 Conference on, 2012Co-Authors: G J KomarAbstract:NASA's Earth Science Technology Office (ESTO) supports a broad range of technology developments. This paper summarizes program investments in electro-optical systems, and highlights progress in two key measurements: column CO2 and Wind Profiles.
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Past, present, and future innovations in active remote sensing: The NASA earth science technology program
Geoscience and Remote Sensing Symposium (IGARSS) 2012 IEEE International, 2012Co-Authors: G J KomarAbstract:The majority of future Earth-science missions will require active remote sensing capabilities. This presentation provides an overview of the technology investments NASA is making in Earth Science, and identifies the active remote sensing investments supporting each measurement. Recent advances in electro-optical technology are enabling two key science measurements: column CO2, and Wind Profiles.
