[GTP] Joint GTP-EOL-MMM seminar-Time change

[Silvia Gentile]

I apologize for the time error.
The lecture is at 3:30pm

Silvia Gentile
NCAR IMAGe
1850 Table Mesa Drive
Boulder, CO 80305
303 497 2480
www2.image.ucar.edu/IMAGe



On 9/23/2011 4:39 PM, Silvia Gentile wrote:
> Joint GTP EOL MMM Seminar
>
> The CIRES Tethered Lifting System: A State-of-the-art Tethersonde for 
> the Measurement and Study of the Structure, Dynamics, and Turbulent 
> Properties of Atmospheric Boundary Layers
> Yannick Mellier
> CIRES (Cooperative Institute for Research in Environmental Sciences), 
> Boulder
>
>
> Understanding the various structures, turbulent properties, and 
> dynamics characterizing atmospheric boundary layers is of the utmost 
> importance for a large number of applications such as Numerical 
> Weather Predictions, Transport & Diffusion, wind energy applications, 
> as well as agricultural and aeronautical meteorology.
> The tethered lifting system (TLS) is a specialty-designed tethersonde 
> system that was developed by the Cooperative Institute for Research in 
> Environmental Sciences (CIRES) at the University of Colorado to 
> complement current measurement systems with unique high-resolution 
> insitu measurements of temperature, velocity, and turbulence.
> Specialty-designed low noise and low power hot-wire (HW) and cold-wire 
> (CW) sensors used in conjunction with a custom-built 16 bit high-rate 
> data acquisition cards measure with high accuracy and precision the 
> changes and fine-scale fluctuations of temperature, windspeed, and 
> turbulence. Inertial range turbulence metrics such as the temperature 
> structure constant CT2 and energy dissipation ε are estimated via 
> spectral processing. The high sensitivity of the detector, low noise 
> properties of the CW/HW circuit cards, and high sampling rate 
> capabilities of the digitizer, allow accurate measurements of high 
> resolution profiles of turbulence at a vertical resolution of 0.5 m or 
> better, and down to extremely weak levels of turbulence of CT2~10-7 
> K2m-2/3 and ε~10-8 m2s-3 (1/10th of a m oC and mm/s fluctuations). In 
> addition to CT2 and ε, the turbulence payload can also measure 
> critical turbulence and dimensionless parameters such as the 
> Kolmogorov and Taylor microscales, the Ozmidov scale, temperature and 
> velocity turbulent length scales, Reynolds number, and turbulent 
> Froude number. The TLS is also ideally suited for accurate 
> measurements of local vertical gradients of temperature and velocity 
> and thus stability parameters such as the gradient Richardson number.
> The TLS is not only highly complementary of current measuring systems 
> such as instrumented meteorological towers and remote sensors but 
> also, thanks to the unique resolution and unprecedented sensitivity of 
> its temperature, velocity, and turbulence measurements, provide new 
> research opportunities. Such research applications include the 
> empirical verification of stably stratified turbulent scaling laws, 
> the validation of remote-sensors measurements of turbulence profiles, 
> an improved understanding of boundary layer (BL) structures and dynamics.
> This seminar will begin with a technical presentation of the TLS 
> system, its principle of operation, measurement performances, and 
> calibration accuracies. The second part of the talk will cover some of 
> the research applications that the TLS has been used for to date and 
> will open the door to suggestions on how such a system could benefit 
> the research interests of NCAR’s Mesoscale and Microscale Meteorology 
> division as well as complement EOL’s current measurement capabilities.
>
>
> Thursday October 27, 2011
> Lecture: 3;30pm (Coffee at 3:15)
> Foothills Laboratory 2, Main Auditorium
>
> This seminar will be recorded
>