A number of remote-sensing wind-measuring instruments, such as LIDAR and radar wind profilers, have been set up in the vicinity of the Hong Kong International Airport (HKIA) for monitoring of low-level windshear and turbulence. The combined usage of wind data from a radar wind profiler and boundary layer temperature profiles from a ground-based microwave radiometer in turbulence application is ...

We investigated the feasibility of using nulling interferometry techniques in the stratosphere to search for extra-solar planets. Studies have shown wavefront distortions from atmospheric turbulence to be too large to obtain clear ground-based images. Wavefront errors caused by atmospheric turbulence in the stratosphere are on the scale of 1 angstrom [4], however, the level of the wavefront err...

With the recent development of wavelet-based techniques for computational fluid dynamics, adaptive numerical simulations of turbulent flows have become feasible [1]. Adaptive wavelet methods are based on wavelet threshold filtering that makes it possible to separate coherent energetic eddies, which are numerically simulated, from residual background flow structures that are filtered out. By var...

Estimates of small-scale turbulence from numerical model output are produced from local estimates of the spatial structure functions of model variables such as velocity and temperature. The key assumptions used are the existence of a universal statistical description of small-scale turbulence and a locally universal spatial filter for the model variables. The shape of the model spatial filter i...

The excitation of stable eigenmodes in unstable plasma turbulence, previously documented in collisionless trapped electron mode turbulence, is shown to be a generic behavior of local quasihomogeneous systems. A condition is derived to indicate when such excited eigenmodes achieve a sufficient level in saturation to affect the turbulence, and produce changes in saturation levels, instability dri...

Potential adaptive wake vortex spacing systems may need to rely on wake vortex decay rather than wake vortex transport in reducing wake separations. Awake vortex takeoff-spacing system in particular will need to rely on wake decay. Ambient turbulence is the primary influence on wake decay away from the ground. This study evaluated 18 months of ambient turbulence measurements at Dallas/F't. Wort...

The Japan Aerospace Exploration Agency has developed the LOw-level Turbulence Advisory System (LOTAS) together with Osaka University. LOTAS introduces new features such as low-cost Doppler radar/lidar, landing difficulty estimation, short-term prediction of radar echo distribution and text message uplink using ACARS to resolve issues related to existing low-level windshear detection and warning...

Plasma shaping e¤ects, such as elongation, triangularity and Shafranov shift have long been considered an important ingredient in improving tokamak performance. It is known that the growth rate of ion temperature gradient (ITG) turbulence can be regulated by these shaping e¤ects and that the ITG turbulence level can also be regulated by zonal ‡ow. Moreover, recent numerical simulation shows tha...

The magnetorotational instability (MRI) is thought to play an important role in enabling accretion in sufficiently ionized astrophysical disks. The rate at which MRI-driven turbulence transports angular momentum is intimately related to both the strength of the amplitudes of the fluctuations on various scales and the degree of anisotropy of the underlying turbulence. This has motivated several ...

Volatiles, especially CO, are important gas tracers of protoplanetary disks (PPDs). Freeze-out and sublimation processes determine their division between gas and solid phases, which affects both which disk regions can be traced by which volatiles, and the formation and composition of planets. Recently, multiple lines of evidence have suggested that CO is substantially depleted from the gas in t...