SLODAR Turbulence Profilers Richard Wilson, Tim Butterley, James Osborn Durham University, UK

SLODAR (SLOpe Detection And Ranging) Shack-Hartmann wavefront sensor Observe double stars Recover C n 2 (h) from the time- averaged cross-covariance of the WFS data

 hh SLODAR Altitude Sampling  h  d/  d (WFS sub-aperture size)

hh Higher Altitude Total SLODAR Altitude Sampling: Ground-Layer profiling

SLODAR Turbulence Profile Sequence, Paranal

SLODAR: Turbulent Layer Velocities Movie shows the spatial cross- covariance with increasing time offset. Motion of peaks => layer velocity (with altitude). Altitude

SLODAR at ESO Paranal: Ground-Layer Characterization

SLODAR Turbulence Profile Sequence, Paranal

All quiet in the ‘gray zone’… Surface layer not resolved SLODAR Turbulence Profile Sequence: Paranal

SLODAR at Paranal Mean Ground-Layer Turbulence Profile Free-Atmosphere Total ~ 45% of optical turbulence within ~70m of the ground

SLODAR Cross-Verification Compare with MASS and DIMM Cannot use the same targets for SLODAR and MASS-DIMM * SLODAR -- DIMM SLODAR MASS-DIMM

SLODAR Cross-Verification: Total Seeing versus DIMM (Paranal) SLODAR DIMM

SLODAR Cross-Verification: Total Seeing versus DIMM (Paranal) Subtract 7x m 1/3 for the first 5m ??? Need ~5m resolution to confirm this …

SLODAR Cross-Verification: Free Atmosphere Seeing versus MASS (Paranal)

SLODAR-LOLAS at Mauna Kea: Ground-Layer Characterization Campaign

Ground-Layer Turbulence: Mauna Kea

SLODAR at SALT: Generalized Profiler - High Altitudes (~15km) Characterize SALT site for AO SLODAR Automation

Correlating surface layer turbulence speed with physical ground wind speed (Mauna Kea data, first try …) : Meteorology: Turbulence Wind Speed UT (hours) Physical Wind Speed (m/s) Turbulence Speed (m/s) Wind Speed

MM5 Model, C n 2 (h) and Wind Velocity Mauna Kea Weather Center Optical Turbulence Forecasting: Model Verification ? Wind Vw(h) C n 2 (h) ?