scholarly journals Characterization of the atmospheric boundary layer from radiosonde observations along eastern end of monsoon trough of India

2014 ◽  
Vol 123 (6) ◽  
pp. 1233-1240 ◽  
Author(s):  
Sagarika Chandra ◽  
Arun K Dwivedi ◽  
Manoj Kumar
Keyword(s):  
Boundary Layer ◽  
Atmospheric Boundary Layer ◽  
Monsoon Trough

scholarly journals High-Resolution Observations of Insects in the Atmospheric Boundary Layer

2008 ◽  
Vol 25 (12) ◽  
pp. 2176-2187 ◽  
Author(s):  
Robert F. Contreras ◽  
Stephen J. Frasier
Keyword(s):  
Boundary Layer ◽  
Atmospheric Boundary Layer ◽  
Cross Sections ◽  
Continuous Monitoring ◽  
Rayleigh Scattering ◽  
Continuous Wave ◽  
Time Of Day ◽  
Fmcw Radar ◽  
Radar Cross Sections

Abstract High spatial and temporal resolution S-band radar observations of insects in the atmospheric boundary layer (ABL) are described. The observations were acquired with a frequency-modulated continuous-wave (FMCW) radar during the 2002 International H20 Project (IHOP_2002) held in Oklahoma in the months of May and June 2002. During the observational period the boundary layer was convective with a few periods of rain. Rayleigh scattering from particulate scatterers (i.e., insects) dominates the return; however, Bragg scattering from refractive index turbulence is also significant, especially at the top of the afternoon boundary layer. There is a strong diurnal signal in the insect backscatter: minima in the morning and at dusk and maxima at night and midafternoon. Insect number densities and radar cross sections (RCSs) are calculated. The RCS values range from less than 10−12 m2 to greater than 10−7 m2 and likewise have a strong diurnal signal. These are converted to equivalent reflectivity measurements that would be reported by typical meteorological radars. The majority of reflectivity measurements from particulate scatterers ranges from −30 to −5 dBZ; however, intense point scatterers (>10 dBZ) are occasionally present. The results show that although insects provide useful targets for characterization of the clear-air ABL, the requirements for continuous monitoring of the boundary layer are specific to time of day and range from −20 dBZ in the morning to −10 to −5 dBZ in the afternoon and nocturnal boundary layer (NBL).

Experimental characterization of atmospheric boundary layer humidity profile

2018 ◽  
Vol 144 (3) ◽  
pp. 1707-1708
Author(s):  
Teresa J. Ryan ◽  
Joseph F. Vignola ◽  
John Judge ◽  
Diego Turo
Keyword(s):  
Boundary Layer ◽  
Atmospheric Boundary Layer ◽  
Experimental Characterization ◽  
Humidity Profile

scholarly journals Characterization of the Vertical Structure of Coastal Atmospheric Boundary Layer over Thumba (, ) during Different Seasons

2011 ◽  
Vol 2011 ◽  
pp. 1-9 ◽  
Author(s):  
Sandhya K. Nair ◽  
T. J. Anurose ◽  
D. Bala Subrahamanyam ◽  
N. V. P. Kiran Kumar ◽  
M. Santosh ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Turbulent Flow ◽  
Atmospheric Boundary Layer ◽  
Mixed Layer ◽  
Seasonal Variability ◽  
Potential Temperature ◽  
Sea Breeze ◽  
The Other ◽  
Vertical Thickness

Vertical profiles of meteorological parameters obtained from balloon-borne GPS Radiosonde for a period of more than two years are analyzed for characterization of the coastal atmospheric boundary layer (CABL) over Thumba (, , India). The study reports seasonal variability in the thickness of three different sublayers of the CABL, namely, mixed layer, turbulent flow, and sea breeze flow. Among the three, the vertical thickness of sea breeze flow showed considerable dominance on the other two throughout the year. Mixed layer heights derived through gradients in virtual potential temperature () showed large seasonal variability with a peak in the Summer and Post-Monsoon. On the other hand, the vertical thickness of turbulent flow remained steady all through the year. Results from the present study indicate that the magnitudes of mixed layer heights are often larger than the turbulent flow thickness.

Fractal Characterization of Temperature Field in Convective Boundary Layer

Fractals ◽  
1997 ◽  
Vol 05 (02) ◽  
pp. 267-274
Author(s):  
Amitabha Chanda ◽  
A. K. Dey ◽  
J. Das
Keyword(s):  
Boundary Layer ◽  
Temperature Field ◽  
Fractal Dimension ◽  
Atmospheric Boundary Layer ◽  
Thermal Energy ◽  
Turbulent Convection ◽  
Convective Boundary ◽  
Local Mean ◽  
Rate Of Dissipation

In turbulent convection, the mean rate of dissipation of thermal energy follows the law of similarity and may be fractally distributed. It may be used as an indicator of the intensity of turbulence. The more intense is turbulence, the greater the fractal dimension (FD) of mean rate of dissipation of thermal energy. In the atmospheric boundary layer (ABL), many types of structures are observed. One of these structures is plume which occurs frequently. In the plume body temperature field is highly random. In between two plumes we generally observe a zone of tranquility, at least in comparative scale. It is conjectured that a plume has a greater fractal dimension than the interplume zone. In the present paper, a two-dimensional analysis of turbulent convection in the atmospheric boundary layer (ABL) was carried out using local intensities of temperature structures as realized from a sodar echogram. It is argued that the local intensities of the temperature structures are linearly related with the local temperatures. A parameter analogous to the local mean of rate of dissipation of thermal energy has been calculated for a series of vertical columns of the echogram and their FD's have been estimated. It has been visually matched with the echogram. It is observed that plumes have greater FDs than the interplume zone.

Characteristics of the Night and Day Time Atmospheric Boundary Layer at Dome C, Antarctica

2007 ◽  
Vol 25 ◽  
pp. 49-55 ◽  
Author(s):  
S. Argentini ◽  
I. Pietroni ◽  
G. Mastrantonio ◽  
A. Viola ◽  
S. Zilitinchevich
Keyword(s):  
Boundary Layer ◽  
Atmospheric Boundary Layer ◽  
Night And Day
Sign in / Sign up

Export Citation Format

Share Document