Angle-of-arrival anemometry by means of a large-aperture Schmidt-Cassegrain telescope equipped with a CCD camera

The frequency spectrum of angle-of-arrival (AOA) fluctuations of optical waves propagating through atmospheric turbulence carries information of wind speed transverse to the propagation path. We present the retrievals of the transverse wind speed, v b , from the AOA spectra measured with a Schmidt-Cassegrain telescope equipped with a CCD camera by estimating the "knee frequency," the intersection of two power laws of the AOA spectrum. The rms difference between 30 s estimates of v b retrieved from the measured AOA spectra and 30 s averages of the transverse horizontal wind speed measured with an ultrasonic anemometer was 11 cm s −1 for a 1 h period, during which the transverse horizontal wind speed varied between 0 and 80 cm s −1 . Potential and limitations of angle-of-arrival anemometry are discusse

METCRAX 2006 - Meteorological experiments in Arizona\u27s Meteor Crater

The Meteor Crater Experiment (METCRAX 2006) was conducted in October 2006 at Arizona\u27s Meteor Crater to investigate stable boundary layer evolution in a topographically uncomplicated basin surrounded by the nearly homogeneous plain of the Colorado Plateau. The two goals of the experiment were 1) to investigate the microscale and mesoscale structure and evolution of the stable boundary layer in the crater and its surroundings and 2) to determine whether atmospheric seiches or standing waves are produced inside the crater. This article provides an overview of the scientific goals of the experiment; summarizes the research measurements, the crater topography, and the synoptic meteorology of the study period; and presents initial analysis results. Analyses show that nighttime temperature inversions form frequently in the crater and that they are often perturbed by internal wave motions. Nighttime cooling produces a shallow (15–30 m deep) surface-based inversion that is surmounted by a horizontally homogeneous near-isothermal layer that extends all the way to the rim, where a second inversion extends above rim level. Seiches are sometimes present on the crater floor. The diurnal propagation of shadows from the crater rim produces important spatial differences in the surface radiation budget and thus the timing of the slope flow transition, and the crater atmosphere is often perturbed during nighttime by a southwesterly mesoscale drainage flow