Numerical simulation of the Doppler lidar measurements with high spatial resolution

2011 ◽  
Author(s):  
Evgeniya A. Shelekhova ◽  
Alexander P. Shelekhov
2014 ◽  
Vol 31 (2) ◽  
pp. 302-325 ◽  
Author(s):  
Howard B. Bluestein ◽  
Jana B. Houser ◽  
Michael M. French ◽  
Jeffrey C. Snyder ◽  
George D. Emmitt ◽  
...  

Abstract During the Second Verification of the Origins of Rotation in Tornadoes Experiment (VORTEX2), in the spring of 2010, a mobile and pulsed Doppler lidar system [the Truck-Mounted Wind Observing Lidar Facility (TWOLF)] mounted on a truck along with a mobile, phased-array, X-band Doppler radar system [Mobile Weather Radar–2005 X-band, phased array (MWR-05XP)] was used to complement Doppler velocity coverage in clear air near the radar–lidar facility and to provide high-spatial-resolution vertical cross sections of the Doppler wind field in the clear-air boundary layer near and in supercells. It is thought that the magnitude and direction of vertical shear and possibly the orientation and spacing of rolls in the boundary layer have significant effects on both supercell and tornado behavior; MWR-05XP and TWOLF can provide data that can be used to measure vertical shear and detect rolls. However, there are very few detailed, time-dependent and spatially varying observations throughout the depth of the boundary layer of supercells and tornadoes. This paper discusses lidar and radar data collected in or near six supercells. Features seen by the lidar included gust fronts, horizontal convective rolls, and small-scale vortices. The lidar proved useful at detecting high-spatial-resolution, clear-air returns at close range, where the radar was incapable of doing so, thus providing a more complete picture of the boundary layer environment ahead of supercells. The lidar was especially useful in areas where there was ground-clutter contamination. When there was precipitation and probably insects, and beyond the range of the lidar, where there was no ground-clutter contamination, the radar was the more useful instrument. Suggestions are made for improving the system and its use in studying the tornado boundary layer.


Author(s):  
K. Przybylski ◽  
A. J. Garratt-Reed ◽  
G. J. Yurek

The addition of so-called “reactive” elements such as yttrium to alloys is known to enhance the protective nature of Cr2O3 or Al2O3 scales. However, the mechanism by which this enhancement is achieved remains unclear. An A.E.M. study has been performed of scales grown at 1000°C for 25 hr. in pure O2 on Co-45%Cr implanted at 70 keV with 2x1016 atoms/cm2 of yttrium. In the unoxidized alloys it was calculated that the maximum concentration of Y was 13.9 wt% at a depth of about 17 nm. SIMS results showed that in the scale the yttrium remained near the outer surface.


Author(s):  
E. G. Rightor

Core edge spectroscopy methods are versatile tools for investigating a wide variety of materials. They can be used to probe the electronic states of materials in bulk solids, on surfaces, or in the gas phase. This family of methods involves promoting an inner shell (core) electron to an excited state and recording either the primary excitation or secondary decay of the excited state. The techniques are complimentary and have different strengths and limitations for studying challenging aspects of materials. The need to identify components in polymers or polymer blends at high spatial resolution has driven development, application, and integration of results from several of these methods.


Author(s):  
Kosuke Nomura ◽  
Ryutaro Oi ◽  
Takanori Senoh ◽  
Taiichiro Kurita ◽  
Takayuki Hamamoto

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