Zobrazeno 1 - 10
of 326
pro vyhledávání: '"Jakob Mann"'
Publikováno v:
Remote Sensing, Vol 14, Iss 23, p 6065 (2022)
Estimates of atmospheric turbulence performed by both fixed and floating vertically profiling, conically scanning wind lidars are affected by the measurement volume and turbulence structure, among others. We study this phenomenon by simulating the li
Externí odkaz:
https://doaj.org/article/df877964aec04226bb8d84818e5cc22d
Publikováno v:
Remote Sensing, Vol 14, Iss 15, p 3576 (2022)
The full-width at half-maximum or probe length of the Lorentzian weighting function of continuous-wave Doppler lidars increases quadratically with the focus distance, which results in a deterioration in the spatial resolution of measurements. What is
Externí odkaz:
https://doaj.org/article/cc189214965b47d9b4f9fbfc4c8dfd49
Publikováno v:
Atmosphere, Vol 12, Iss 6, p 672 (2021)
It is well known that when eddies are small, the eddy fluxes can be directly related to the mean vertical gradients, the so-called flux-gradient relation, but such a relation becomes weaker the larger the coherent structures. Here, we show that this
Externí odkaz:
https://doaj.org/article/220144d3bd4a4d7fbd7aef2a0fa07691
Publikováno v:
Remote Sensing, Vol 12, Iss 5, p 898 (2020)
Due to their motion, floating wind lidars overestimate turbulence intensity ( T I ) compared to fixed lidars. We show how the motion of a floating continuous-wave velocity−azimuth display (VAD) scanning lidar in all six degrees of freedom influence
Externí odkaz:
https://doaj.org/article/b4b2b1a921364fb6bb10a1819f59e439
Autor:
Alfredo Peña, Jakob Mann
Publikováno v:
Remote Sensing, Vol 11, Iss 20, p 2444 (2019)
Velocity-component variances can be directly computed from lidar measurements using information of the second-order statistics within the lidar probe volume. Specifically, by using the Doppler radial velocity spectrum, one can estimate the unfiltered
Externí odkaz:
https://doaj.org/article/77169615775444e0a9c419ce37797a02
Publikováno v:
Meteorologische Zeitschrift, Vol 18, Iss 3, Pp 281-287 (2009)
The influence of spatial volume averaging of a focused continuous-wave coherent Doppler lidar on observed wind turbulence in the atmospheric surface layer is described and analysed. For the first time, comparisons of lidar-measured turbulent spectra
Externí odkaz:
https://doaj.org/article/cec9f8d369cf4800bca4cf1185ed94ef
Autor:
Jakob Mann, Jean-Pierre Courtney Cariou, Rèmy Mikkelsen Parmentier, Rozenn Wagner, Petter Lindelöw, Mikael Sjöholm, Karen Enevoldsen
Publikováno v:
Meteorologische Zeitschrift, Vol 18, Iss 2, Pp 135-140 (2009)
The goals are to compare lidar volume averaged wind measurement with point measurement reference sensors and to demonstrate the feasibility of performing 3D turbulence measurements with lidars. For that purpose three pulsed lidars were used in starin
Externí odkaz:
https://doaj.org/article/e6dc8efb2af04af691648625a3553dd9
Publikováno v:
Meteorologische Zeitschrift, Vol 18, Iss 2, Pp 189-195 (2009)
Conically scanning lidars assume the flow to be homogeneous in order to deduce the horizontal wind speed. However, in mountainous or complex terrain this assumption is not valid implying a risk that the lidar will derive an erroneous wind speed. The
Externí odkaz:
https://doaj.org/article/016ab2a4388d409695f815ccf7cb7fc2
Autor:
Etienne Cheynet, Jasna B. Jakobsen, Jónas Snæbjörnsson, Jakob Mann, Michael Courtney, Guillaume Lea, Benny Svardal
Publikováno v:
Remote Sensing, Vol 9, Iss 10, p 977 (2017)
Three synchronized pulsed Doppler wind lidars were deployed from May 2016 to June 2016 on the shores of a wide Norwegian fjord called Bjørnafjord to study the wind characteristics at the proposed location of a planned bridge. The purpose was to inve
Externí odkaz:
https://doaj.org/article/6e4b17c9cf06468f87de4d2846e04ef5
Autor:
Julia Lange, Jakob Mann, Jacob Berg, Dan Parvu, Ryan Kilpatrick, Adrian Costache, Jubayer Chowdhury, Kamran Siddiqui, Horia Hangan
Publikováno v:
Environmental Research Letters, Vol 12, Iss 9, p 094020 (2017)
The cost of energy produced by onshore wind turbines is among the lowest available; however, onshore wind turbines are often positioned in a complex terrain, where the wind resources and wind conditions are quite uncertain due to the surrounding topo
Externí odkaz:
https://doaj.org/article/217a079f1fe441a19b8744c081ffabd2