Search Results
and aerosol backscatter/extinction coefficients for lidar systems when narrowband interference filters are used [full width half maximum (FWHM) of a few nanometers or less]. Narrowband detection is employed to reduce the background skylight along with the use of a narrow field-of-view (FOV) telescope, without substantially reducing the Raman signals ( Bisson et al. 1999 ). Moreover, along with a high-power laser and combined analog-to-digital and photon counting data acquisition, it can be used to
and aerosol backscatter/extinction coefficients for lidar systems when narrowband interference filters are used [full width half maximum (FWHM) of a few nanometers or less]. Narrowband detection is employed to reduce the background skylight along with the use of a narrow field-of-view (FOV) telescope, without substantially reducing the Raman signals ( Bisson et al. 1999 ). Moreover, along with a high-power laser and combined analog-to-digital and photon counting data acquisition, it can be used to
1. Introduction A theoretical model is developed to estimate the systematic errors in the second-order moments of wind speeds in the atmospheric surface layer measured by lidars. The systematic errors are those that arise resulting from the averaging effect in the sample or pulse volume and the relatively large circle in which Doppler lidars scan to obtain two-component horizontal wind profiles. Two types of lidars are considered, the ZephIR, developed by QinetiQ (Natural Power), as a
1. Introduction A theoretical model is developed to estimate the systematic errors in the second-order moments of wind speeds in the atmospheric surface layer measured by lidars. The systematic errors are those that arise resulting from the averaging effect in the sample or pulse volume and the relatively large circle in which Doppler lidars scan to obtain two-component horizontal wind profiles. Two types of lidars are considered, the ZephIR, developed by QinetiQ (Natural Power), as a
1. Measurement technique Lidar is a remote sensing technique that transmits a laser beam into the atmosphere and the backscattered light is detected. The pulsed Doppler wind lidar, which was used for the measurements in Bremerhaven, Germany, takes advantage of the fact that the center frequency of the received laser pulses is shifted compared to the outgoing pulses because of the Doppler effect, which occurs from backscattering on moving particles. This shift in frequency provides information
1. Measurement technique Lidar is a remote sensing technique that transmits a laser beam into the atmosphere and the backscattered light is detected. The pulsed Doppler wind lidar, which was used for the measurements in Bremerhaven, Germany, takes advantage of the fact that the center frequency of the received laser pulses is shifted compared to the outgoing pulses because of the Doppler effect, which occurs from backscattering on moving particles. This shift in frequency provides information
1. Introduction This paper describes the design and performance of the Cloud–Aerosol Lidar with Orthogonal Polarization (CALIOP), a three-channel elastic backscatter lidar that is the prime payload instrument on the Cloud–Aerosol Lidar and Infrared Pathfinder Satellite Observation ( CALIPSO ) satellite. It provides background material for a collection of CALIOP algorithm papers that are to be published in the Journal of Atmospheric and Oceanic Technology ( Winker et al. 2009 ). CALIPSO was
1. Introduction This paper describes the design and performance of the Cloud–Aerosol Lidar with Orthogonal Polarization (CALIOP), a three-channel elastic backscatter lidar that is the prime payload instrument on the Cloud–Aerosol Lidar and Infrared Pathfinder Satellite Observation ( CALIPSO ) satellite. It provides background material for a collection of CALIOP algorithm papers that are to be published in the Journal of Atmospheric and Oceanic Technology ( Winker et al. 2009 ). CALIPSO was
Barthelmie et al. (2003) and with other models in Barthelmie et al. (2006) . A coherent Doppler lidar system (CDL) is a powerful tool that can measure wind, turbulence, and aircraft wake vortices ( Köpp et al. 1984 ; Hall et al. 1984 ; Hawley et al. 1993 ; Frehlich et al. 1994 , 1998 ; Banakh et al. 1999 ; Köpp et al. 2005 ; Smalikho et al. 2005 ; Banta et al. 2006 ; Frehlich et al. 2006 ; Pichugina et al. 2008 ; Rahm and Smalikho 2008 ; Banakh et al. 2009 ; Pichugina and Banta 2010 ; O
Barthelmie et al. (2003) and with other models in Barthelmie et al. (2006) . A coherent Doppler lidar system (CDL) is a powerful tool that can measure wind, turbulence, and aircraft wake vortices ( Köpp et al. 1984 ; Hall et al. 1984 ; Hawley et al. 1993 ; Frehlich et al. 1994 , 1998 ; Banakh et al. 1999 ; Köpp et al. 2005 ; Smalikho et al. 2005 ; Banta et al. 2006 ; Frehlich et al. 2006 ; Pichugina et al. 2008 ; Rahm and Smalikho 2008 ; Banakh et al. 2009 ; Pichugina and Banta 2010 ; O
1. Introduction Lidar systems are able to provide information about the wind field approaching a wind turbine in advance, which can be used to assist wind turbine control. This field of investigations has increased significantly in recent years, and several controllers for load reduction or energy yield increase have been tested in simulations (see, e.g., Laks et al. 2010 ; Dunne et al. 2012 ; Schlipf et al. 2013b ; Koerber and King 2011 ; Henriksen 2011 ; Kragh et al. 2013 ). The latest
1. Introduction Lidar systems are able to provide information about the wind field approaching a wind turbine in advance, which can be used to assist wind turbine control. This field of investigations has increased significantly in recent years, and several controllers for load reduction or energy yield increase have been tested in simulations (see, e.g., Laks et al. 2010 ; Dunne et al. 2012 ; Schlipf et al. 2013b ; Koerber and King 2011 ; Henriksen 2011 ; Kragh et al. 2013 ). The latest
balloons. Pulsed Doppler lidar ( Huffaker and Hardesty 1996 ; Grund et al. 2001 ), the optical analog of Doppler radar, is a remote sensing technology that has now developed past bespoke systems operated by research organizations to the point where meteorological end users can operate commercially available instruments for long-term, autonomous deployments. Instruments of this type have the capability to remotely measure the dynamics and particulate levels in the atmosphere and have the attractive
balloons. Pulsed Doppler lidar ( Huffaker and Hardesty 1996 ; Grund et al. 2001 ), the optical analog of Doppler radar, is a remote sensing technology that has now developed past bespoke systems operated by research organizations to the point where meteorological end users can operate commercially available instruments for long-term, autonomous deployments. Instruments of this type have the capability to remotely measure the dynamics and particulate levels in the atmosphere and have the attractive
key processes, measurements of higher temporal resolution are required. Lidar measurements of tropospheric water vapor have been collected at Ny-Ålesund since June 2001 ( Gerding et al. 2004 ), and the first results from a Raman lidar at Sondrestrom, Greenland, have also recently been published ( Neely and Thayer 2011 ). During all seasons but summer, the boundary layer tends to be very stable with radiative cooling of the surface producing a strong temperature inversion ( Curry et al. 1996 and
key processes, measurements of higher temporal resolution are required. Lidar measurements of tropospheric water vapor have been collected at Ny-Ålesund since June 2001 ( Gerding et al. 2004 ), and the first results from a Raman lidar at Sondrestrom, Greenland, have also recently been published ( Neely and Thayer 2011 ). During all seasons but summer, the boundary layer tends to be very stable with radiative cooling of the surface producing a strong temperature inversion ( Curry et al. 1996 and
1. Background This research note briefly introduces a new approach to wave measurements based upon shallow angle lidars and highlights new metrology issues specific to the method. The technique is capable of measuring the time evolution of spatial profiles of sea waves over an extended region of several hundred meters for effectively unlimited periods of time. The measurement of time-resolved spatial profiles of propagating sea waves has obvious applications in fundamental wave research and in
1. Background This research note briefly introduces a new approach to wave measurements based upon shallow angle lidars and highlights new metrology issues specific to the method. The technique is capable of measuring the time evolution of spatial profiles of sea waves over an extended region of several hundred meters for effectively unlimited periods of time. The measurement of time-resolved spatial profiles of propagating sea waves has obvious applications in fundamental wave research and in
sensing (e.g., lidar) has many attractive properties, such as the ability to make measurements in the absence of sunlight and to provide detailed range profile information. However, to perform this range-dependent inversion, at least two independent lidar signals have to be measured, or a relationship between attenuation ( α ) and backscatter ( β ) has to be assumed. This can be seen by examining the lidar equation, which expresses received signal power P S as a function of range R , defined as
sensing (e.g., lidar) has many attractive properties, such as the ability to make measurements in the absence of sunlight and to provide detailed range profile information. However, to perform this range-dependent inversion, at least two independent lidar signals have to be measured, or a relationship between attenuation ( α ) and backscatter ( β ) has to be assumed. This can be seen by examining the lidar equation, which expresses received signal power P S as a function of range R , defined as
