We present recent studies on the impact of phase and amplitude fluctuations on Doppler lidars using coherent detection. As there is an emphasis on elucidating those implications of the atmospheric propagation problem that bear on the design and reliability of optical coherent lidar systems, we consider in a unified framework the effects of atmospheric turbulence and diffuse target speckle on th...

The power generated by a wind turbine largely depends on the wind speed. During time periods with identical hub-height wind speeds but different shapes to the wind profile, a turbine will produce different amounts of power. This variability may be induced by atmospheric stability, which affects profiles of mean wind speed, direction and turbulence across the rotor disk. Our letter examines turb...

In spite of the several technical advantages of a freespace optical (FSO) communication, atmospheric turbulence can severely degrade the performance of a FSO link, because it creates random fluctuations in the phase and the amplitude of the received signal. The simultaneous usage of multiple transmit/receive apertures (MIMO) can mitigate the fading effects, that is particularly crucial for stro...

A mathematical system model for a compact heterodyne-reception infrared radar is developed. This model incorporates the statistical effects of propagation through atmospheric turbulence, target speckle and glint, and heterodyne-reception shot noise. It is used to find the image signal-to-noise ratio of a matched-filter envelope-detector receiver and the target detection probability of the optim...

The ocean surface boundary layer mediates air-sea exchange. In the classical paradigm and in current climate models, its turbulence is driven by atmospheric forcing. Observations at a 1-kilometer-wide front within the Kuroshio Current indicate that the rate of energy dissipation within the boundary layer is enhanced by one to two orders of magnitude, suggesting that the front, rather than the a...

Error-control codes can help to mitigate atmospheric turbulence-induced signal fading in free-space optical communication links using intensity modulation/direct detection (IM/DD). Error performance bound analysis can yield simple analytical upper bounds or approximations to the bit-error probability. In this letter, we first derive an upper bound on the pairwise codeword-error probability for ...

Optical beam wander is one of the most important issues for free-space optical (FSO) communication. We theoretically derive a beam wander model for Bessel beams propagating in turbulent atmosphere. The calculated beam wander of high order Bessel beams with different turbulence strengths are consistent with experimental measurements. Both theoretical and experimental results reveal that high ord...

We theoretically study the performance of multiple-input multiple-output (MIMO) free-space optical (FSO) systems using subcarrier quadrature modulation (SC-QAM) signaling. The system average symbolerror rate (ASER) is derived taking into account the atmospheric turbulence effects on the MIMO/FSO channel, which is modeled by log-normal and the gamma-gamma distributions for weak and moderate-to-s...

FSO communication systems links is vulnerable due to degrading effects of atmospheric turbulence and point errors. We investigate the error rate performance of Free-Space Optical (FSO) links over gamma-gamma turbulence fading channels in the presence of pointing error. Assuming Intensity-Modulation/Direct Detection (IM/DD) with On-Off Keying (OOK), a novel closed-form expression for BER of FSO ...

The influence of streamline curvature on small-scale turbulence and vertical mixing in stratified fluids is the subject of this study. The roles of curvature and stratification in enhancing and suppressing turbulent mixing are explored using second-moment closure for turbulence. Governing equations for second moments are expressed in generalized orthogonal curvilinear coordinates, from which, t...