Development and evaluation of airborne microwave refractometer for studies on atmospheric tropical boundary layer radiorefractive index

1994 ◽  
Vol 12 (8) ◽  
pp. 785-793 ◽  
Author(s):  
S. B. S. S. Sarma ◽  
B. M. Reddy
Keyword(s):  
Boundary Layer ◽  
Communication Systems ◽  
Electromagnetic Propagation ◽  
Tropical Country ◽  
High Resolution Data ◽  
Layer Structures ◽  
Efficient Communication ◽  
Low Altitude ◽  
Time Basis ◽  
Future Direction

Abstract. Observations of high-resolution data on radio refractivity were obtained by the airborne microwave refractometer over the Indian sub-continent (a tropical country) from 1971 to 1988. Detailed vertical and horizontal distributions of radio refractivity on a near-real-time basis in the atmospheric boundary layer were determined . Radiosonde observations cannot detect the thin refractivity gradients which characterize the propagation environment in this low-altitude region. This knowledge is required to design reliable and efficient communication systems for strategic, tactical and operational needs. However, the results demonstrate the layer structures and the variability of the boundary layer in time and space. The radio refractive effects on electromagnetic propagation and the future direction of radio refractivity fine-structure measurements are discussed.

Finescale Dual-Doppler Analysis of Hurricane Boundary Layer Structures in Hurricane Frances (2004) at Landfall

2014 ◽  
Vol 142 (5) ◽  
pp. 1874-1891 ◽  
Author(s):  
Karen A. Kosiba ◽  
Joshua Wurman
Keyword(s):  
Boundary Layer ◽  
Three Dimensional ◽  
Transient Nature ◽  
Layer Structures ◽  
Characteristic Wavelength ◽  
Doppler Data ◽  
Mean Wind Speed ◽  
Average Flux ◽  
Hurricane Boundary Layer ◽  
The Right

Abstract Two Doppler on Wheels (DOW) mobile radars collected fine-spatial-scale dual-Doppler data in the right-front quadrant and eye of Hurricane Frances (2004) as it made landfall near Stuart, Florida. A 5.7-km dual-Doppler baseline established a dual-Doppler domain south and east of Fort Pierce, Florida, encompassing a 5.5 km × 5.5 km horizontal area, with a grid spacing of 20 m, allowing for the resolution of subkilometer-scale horizontal structures and associated kinematics. Three-dimensional vector wind analyses of the boundary layer revealed the presence of linear coherent structures with a characteristic wavelength of 400–500 m near the surface that increased in size and became more cellular in shape with increasing height. Average horizontal perturbation winds were proportional to average total horizontal winds. Within the eye of the hurricane, the features lost linear coherency despite a high mean wind speed, possibly due to changes in stability. A slight decrease in the characteristic wavelength of boundary layer structures was documented as the winds cross the barrier islands east of Fort Pierce. Vertical flux of horizontal momentum caused by individual vortical structures was substantially higher than values employed in turbulence parameterization schemes, but the domain-wide average flux was substantially lower than that in individual structures, likely due to the transient nature of the most intense portions of the structures. Analysis of the turbulent kinetic energy (TKE) yielded values comparable to those reported in previous observational studies over the open ocean. However, there was substantial variability in TKE within the dual-Doppler domain, emphasizing the challenge in obtaining representative samples using non-3D measurements such as dropsondes.

Measurement of boundary layer structures in chocolate cooling process

2020 ◽  
Vol 2020 (0) ◽  
pp. OS05-12
Author(s):  
Kento YAMADA ◽  
Hyun Jin PARK ◽  
Yuji TASAKA ◽  
Yuichi MURAI
Keyword(s):  
Boundary Layer ◽  
Cooling Process ◽  
Layer Structures

Power Management Technique for Energy-Efficient Communication Systems in Telemedicine

2021 ◽  
pp. 115-143
Author(s):  
K. Sujatha ◽  
N. P. G. Bhavani ◽  
Rajeswary Hari ◽  
K. Senthil Kumar ◽  
N. Jayachitra ◽  
...  
Keyword(s):  
Power Management ◽  
Energy Efficient ◽  
Communication Systems ◽  
Management Technique ◽  
Energy Efficient Communication ◽  
Efficient Communication

scholarly journals Supercapillary Architecture‐Activated Two‐Phase Boundary Layer Structures for Highly Stable and Efficient Flow Boiling Heat Transfer

2019 ◽  
Vol 32 (2) ◽  
pp. 1905117 ◽  
Author(s):  
Wenming Li ◽  
Zuankai Wang ◽  
Fanghao Yang ◽  
Tamanna Alam ◽  
Mengnan Jiang ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Phase Boundary ◽  
Boiling Heat Transfer ◽  
Flow Boiling ◽  
Two Phase ◽  
Layer Structures ◽  
Flow Boiling Heat Transfer

scholarly journals HIGH-RESOLUTION TSUNAMI-BEDLOAD COUPLED COMPUTATION IN AMR ENVIRONMENT

2018 ◽  
pp. 21
Author(s):  
Yasunori Watanabe ◽  
Yuta Mitobe ◽  
Hitoshi Tanaka ◽  
Kazuya Watanabe
Keyword(s):  
Boundary Layer ◽  
Land Use ◽  
High Resolution ◽  
Boundary Layer Theory ◽  
Wall Roughness ◽  
Pressure Reduction ◽  
High Resolution Data ◽  
Public Facilities ◽  
Elevation Data ◽  
Resolution Data

Conventional tsunami computations on coarser grids have employed Manning’s friction coefficients of subgrid equivalent roughness for buildings, vegetation and public facilities (roads, dikes and so on), depending on land-use at the grid location. This equivalent roughness macroscopically models to integrate all effects of resistances against the flow within the computational cells; that is, drag force and pressure reduction behind structures in addition to wall roughness defined in turbulent boundary layer theory. Recently high-resolution land elevation data (2-m resolution), measured by an aerial laser profiler, has been used for computing local inundation of tsunami flood. Since the high-resolution data resolves major buildings and facilities, the mechanical contributions of the structures, such as drag and pressure reduction, are included in the computed result. In this case, conventional equivalent friction may be unacceptable to use.

Research on Application of Tunable Dispersion Compensation Technology in Optical Fiber Communication Systems

2013 ◽  
Vol 401-403 ◽  
pp. 1956-1959
Author(s):  
Wen Xuan Gai
Keyword(s):  
Communication Systems ◽  
Dispersion Compensation ◽  
Optical Fiber Communication ◽  
Fiber Grating ◽  
Basic Principles ◽  
Fiber Communication ◽  
Future Direction ◽  
Chirped Fiber Grating ◽  
Research On Application ◽  
Communications System

For high bit-rate optical communications system, the changes in temperature or power fluctuations are due to the dispersion of the dispersion tolerance than the system. Therefore, the dispersion compensation unit must have the functionality to adapt to the dynamic generation of tunable optical communication network development. This article describes several dynamic tunable compensation techniques and the basic principles of the performance characteristics of the situation at home and abroad, including the chirped fiber grating method, the virtual image phased array method, GT interferometer method, the array method and the planar waveguide grating method, and a brief discussion of tunable dispersion compensation technology in the future direction of development.

scholarly journals Observation of a Severe Wind Case Caused by Gust Front and Its Boundary Layer Structures Characteristics

2018 ◽  
Vol 53 ◽  
pp. 03010
Author(s):  
Changyi Xu ◽  
Yan Wang
Keyword(s):  
Boundary Layer ◽  
Doppler Radar ◽  
Main Body ◽  
Observation Data ◽  
High Wind ◽  
Layer Structures ◽  
Wind Profiler Radar ◽  
Outflow Boundary ◽  
Wind Intensity ◽  
Gust Front

Based on Doppler radar 3D-composited reflectivity, wind profiler radar, boundary layer Tianjin tower of 255m as well as intensified automatic surface observation data, the evolution of the boundary layer associated with two successive gust front processes in the evening of 10 June 2016 and the intensity of the related disastrous surface high wind were analyzed. The results shown as follows: (1) To the same storm cell, the wind intensity caused by the outflow boundary in the main body was stronger than the wind caused by the gust front. The intensity of the disastrous high wind was related to the maximum descending velocity in the boundary layer and the associated height. The stronger the maximum descending velocity and the lower the level, the stronger the disastrous high wind was. (2) The tower data indicated, as the approaching of the gust front, convergence fluctuations first emerged at low(20m) and middle(120m) levels of the tower, leading the emergence of disastrous high wind by 8 minutes. When the gust front passed over, the maximum variations of cooling and the wind velocity were in pace with each other.

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