Search Results
–Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) satellite, launched in 2006, carries a two-wavelength polarization lidar, the first space-based lidar optimized for cloud and aerosol layer detection. This instrument is capable of detecting subvisible cirrus layers with optical depths of 0.01 or less ( Winker et al. 2007 ). Two contrasting formation mechanisms for TTL cirrus have been advanced in the literature: Detrainment: Outflow from the anvil region of deep convective clouds has
–Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) satellite, launched in 2006, carries a two-wavelength polarization lidar, the first space-based lidar optimized for cloud and aerosol layer detection. This instrument is capable of detecting subvisible cirrus layers with optical depths of 0.01 or less ( Winker et al. 2007 ). Two contrasting formation mechanisms for TTL cirrus have been advanced in the literature: Detrainment: Outflow from the anvil region of deep convective clouds has
Satellite (TIROS-N) Operational Vertical Sounder (TOVS) spaceborne instruments, and from a couple of ground lidars in France. Also, high-cloud optical thicknesses from GLAS are compared similarly from a number of worldwide multiyear ground-based lidar datasets. The second motivation comes from the fact that high clouds strongly affect the performances of any airborne electro-optical sensor for limb-viewing observations. Chervet and Roblin (2006) have developed a model to determine the performance
Satellite (TIROS-N) Operational Vertical Sounder (TOVS) spaceborne instruments, and from a couple of ground lidars in France. Also, high-cloud optical thicknesses from GLAS are compared similarly from a number of worldwide multiyear ground-based lidar datasets. The second motivation comes from the fact that high clouds strongly affect the performances of any airborne electro-optical sensor for limb-viewing observations. Chervet and Roblin (2006) have developed a model to determine the performance
uncertainty and contributes up to 70% of the total error. In addition, those errors can be horizontally correlated over several hundred kilometers ( Bormann et al. 2003 ). As a consequence, AMVs are usually thinned rigorously for the assimilation in NWP models. Spaceborne lidars such as the one on the Cloud–Aerosol Lidar and Infrared Pathfinder Satellite Observations ( CALIPSO ) satellite can accurately determine the height of cloud tops. Therefore, the combination of AMVs with cloud-top information
uncertainty and contributes up to 70% of the total error. In addition, those errors can be horizontally correlated over several hundred kilometers ( Bormann et al. 2003 ). As a consequence, AMVs are usually thinned rigorously for the assimilation in NWP models. Spaceborne lidars such as the one on the Cloud–Aerosol Lidar and Infrared Pathfinder Satellite Observations ( CALIPSO ) satellite can accurately determine the height of cloud tops. Therefore, the combination of AMVs with cloud-top information
–stratosphere–troposphere/incoherent scatter (MST/IS) radar mainly sensitive to humidity and temperature irregularities in the neutral atmosphere and to electron density fluctuations in the ionized atmosphere. During observations performed in 7–8 June 2006, the MU radar revealed 0.5–2-km-deep turbulent layers with roll-like appearance developing downward below 8.0 km above mean sea level (MSL). Coincident observations with a Rayleigh–Mie–Raman (RMR) lidar ( Behrendt et al. 2004 ) showed a 4-km-deep layer of cirrus above 8.0 km. The
–stratosphere–troposphere/incoherent scatter (MST/IS) radar mainly sensitive to humidity and temperature irregularities in the neutral atmosphere and to electron density fluctuations in the ionized atmosphere. During observations performed in 7–8 June 2006, the MU radar revealed 0.5–2-km-deep turbulent layers with roll-like appearance developing downward below 8.0 km above mean sea level (MSL). Coincident observations with a Rayleigh–Mie–Raman (RMR) lidar ( Behrendt et al. 2004 ) showed a 4-km-deep layer of cirrus above 8.0 km. The
ground-based wind observations in the boundary layer in and near supercells (mostly in the inflow region and just behind the rear-flank gust front), some tornadic, from a very high-spatial resolution, mobile, pulsed Doppler lidar and collocated, mobile, phased-array, X-band Doppler radar data ( Bluestein et al. 2010 ); and 2) to make a case for the use of the lidar for probing the boundary layer of tornadoes. The data were collected during the second year of the Second Verification of the Origins of
ground-based wind observations in the boundary layer in and near supercells (mostly in the inflow region and just behind the rear-flank gust front), some tornadic, from a very high-spatial resolution, mobile, pulsed Doppler lidar and collocated, mobile, phased-array, X-band Doppler radar data ( Bluestein et al. 2010 ); and 2) to make a case for the use of the lidar for probing the boundary layer of tornadoes. The data were collected during the second year of the Second Verification of the Origins of
of flux parameterizations in mesoscale and general circulation models. Such observations can only be done with remote sensing instruments that provide the parameters of interest with high accuracy (<5%–10%) and with a spatial resolution of the order of 50 m and a temporal resolution of a few seconds. Remote measurements of turbulent fluxes in the planetary boundary layer were first shown by Senff et al. (1994) . A water vapor differential absorption lidar (DIAL) was combined with a radar radio
of flux parameterizations in mesoscale and general circulation models. Such observations can only be done with remote sensing instruments that provide the parameters of interest with high accuracy (<5%–10%) and with a spatial resolution of the order of 50 m and a temporal resolution of a few seconds. Remote measurements of turbulent fluxes in the planetary boundary layer were first shown by Senff et al. (1994) . A water vapor differential absorption lidar (DIAL) was combined with a radar radio
small, easily handled aerosol lidar from the new generation of micropulse lidars [MPL version 4 (MPL-4), Sigma Space Corporation] at Belgrano Station, Antarctica (78°S, 34°W). Belgrano remains well inside the vortex during wintertime ( Parrondo et al. 2007 ) providing an excellent location for PSC observations. This new equipment will complete the Antarctic program, which INTA is performing continuously from 1994 for stratospheric ozone monitoring and research. Older versions than MPL-4 are already
small, easily handled aerosol lidar from the new generation of micropulse lidars [MPL version 4 (MPL-4), Sigma Space Corporation] at Belgrano Station, Antarctica (78°S, 34°W). Belgrano remains well inside the vortex during wintertime ( Parrondo et al. 2007 ) providing an excellent location for PSC observations. This new equipment will complete the Antarctic program, which INTA is performing continuously from 1994 for stratospheric ozone monitoring and research. Older versions than MPL-4 are already
disappears almost completely due to the advection and mixing of humid air masses into the free troposphere. The lidar observed a different pattern of development for the vertical water vapor distribution. The dry layer persisted until the arrival of the MCS. This observation explains the deviations between the observations and the model at this height range. The advection of moister air masses in the free troposphere forecasted by COSMO-DE is also less dominant in the lidar observations. The dry layer
disappears almost completely due to the advection and mixing of humid air masses into the free troposphere. The lidar observed a different pattern of development for the vertical water vapor distribution. The dry layer persisted until the arrival of the MCS. This observation explains the deviations between the observations and the model at this height range. The advection of moister air masses in the free troposphere forecasted by COSMO-DE is also less dominant in the lidar observations. The dry layer
assimilation in NWP models and only a small fraction of the available observations is used. Preceding studies ( Velden and Bedka 2009 ; Weissmann et al. 2013 ) demonstrated that AMVs actually represent the wind in a vertically extended layer, although they are traditionally assimilated at discrete levels. In addition, Weissmann et al. (2013) showed that the height of AMVs can be corrected using airborne lidar cloud-top observations. The study presented here further investigates these two approaches that
assimilation in NWP models and only a small fraction of the available observations is used. Preceding studies ( Velden and Bedka 2009 ; Weissmann et al. 2013 ) demonstrated that AMVs actually represent the wind in a vertically extended layer, although they are traditionally assimilated at discrete levels. In addition, Weissmann et al. (2013) showed that the height of AMVs can be corrected using airborne lidar cloud-top observations. The study presented here further investigates these two approaches that
1. Introduction Observations from spaceborne lidar provide a novel perspective on clouds. The lidar is able to directly measure the height of multiple cloud layers, provided the upper layers are not optically thick. A variety of studies have examined overlap statistics ( Wang and Dessler 2006 ), distributions of cloud-top and -base heights ( Hart et al. 2005 ; Dessler et al. 2006b ), and the occurrence and backscatter properties of optically thin clouds ( Dessler et al. 2006a ). There are also
1. Introduction Observations from spaceborne lidar provide a novel perspective on clouds. The lidar is able to directly measure the height of multiple cloud layers, provided the upper layers are not optically thick. A variety of studies have examined overlap statistics ( Wang and Dessler 2006 ), distributions of cloud-top and -base heights ( Hart et al. 2005 ; Dessler et al. 2006b ), and the occurrence and backscatter properties of optically thin clouds ( Dessler et al. 2006a ). There are also
