The main purpose of this work is to describe a major field project on fog and summarize the preliminary results. Three field phases of the Fog Remote Sensing and Modeling (FRAM) project were conducted over the following two regions of Canada: 1) the Center for Atmospheric Research Experiments (CARE), in Toronto, Ontario (FRAM-C), during the winter of 2005/06, and 2) Lunenburg, Nova Scotia (FRAM-L), during June 2006 and June 2007. Fog conditions observed during FRAM-C were continental in nature, while those conditions observed during FRAM-L were of marine origin. The main objectives of the project were to attain 1) a better description of fog environments, 2) the development of microphysical parameterizations for model applications, 3) the development of remote sensing methods for fog nowcasting/forecasting, 4) an understanding of issues related to instrument capabilities and improvement of the analysis, and 5) an integration of model data with observations to predict and detect fog areas and particle phas...

The Fog Remote Sensing and Modeling Field Project

Disclosed is a laser radar device having a wide two-dimensional field of view, a large receiving aperture, and responsivity to short pulse light. Specifically disclosed is a laser radar device provided with a laser light source which generates pulse laser light, a scanner which transmits a transmission pulse to a target while two-dimensionally scanning a pencil-shaped transmission beam and outputs scan angle information, a reception lens which receives reception light that has arrived, a long light-receiving element array which converts the reception light to reception signals and outputs the reception signals, a transimpedance amplifier array which amplifies the reception signals, an adder circuit which adds the reception signals from respective elements of the transimpedance amplifier array, a distance detection circuit which measures the light round-trip time to the target of an output signal from the adder circuit, and a signal processing unit which obtains the distances to multiple points on the target on the basis of the light round-trip time and the light speed by causing the scanner to perform a two-dimensional scan operation while associating the two-dimensional scan operation with the scan angle information to thereby measure the three-dimensional shape of the target.

Laser radar device

This review paper summarizes current knowledge available for aviation operations related to meteorology and provides suggestions for necessary improvements in the measurement and prediction of weather-related parameters, new physical methods for numerical weather predictions (NWP), and next-generation integrated systems. Severe weather can disrupt aviation operations on the ground or in-flight. The most important parameters related to aviation meteorology are wind and turbulence, fog visibility, aerosol/ash loading, ceiling, rain and snow amount and rates, icing, ice microphysical parameters, convection and precipitation intensity, microbursts, hail, and lightning. Measurements of these parameters are functions of sensor response times and measurement thresholds in extreme weather conditions. In addition to these, airport environments can also play an important role leading to intensification of extreme weather conditions or high impact weather events, e.g., anthropogenic ice fog. To observe meteorological parameters, new remote sensing platforms, namely wind LIDAR, sodars, radars, and geostationary satellites, and in situ instruments at the surface and in the atmosphere, as well as aircraft and Unmanned Aerial Vehicles mounted sensors, are becoming more common. At smaller time and space scales (e.g., < 1 km), meteorological forecasts from NWP models need to be continuously improved for accurate physical parameterizations. Aviation weather forecasts also need to be developed to provide detailed information that represents both deterministic and statistical approaches. In this review, we present available resources and issues for aviation meteorology and evaluate them for required improvements related to measurements, nowcasting, forecasting, and climate change, and emphasize future challenges.

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A Review of High Impact Weather for Aviation Meteorology

Marine fog: A review

A review on ice fog measurements and modeling

To observe fog, a 35-GHz scanning Doppler radar was designed, assembled, and tested. The radar, mounted on a flatbed vehicle for portability, transmits peak powers of 100 kW in a pulse of 0.5-µs width and a beamwidth of 0.3°. Thus, a reflectivity factor Z of −20 dBZ at a range of 10 km generates a signal-to-noise ratio of 0 dB. Doppler velocity measurements are made by sampling the radio frequency phase within each pulse transmitted by a magnetron oscillator and referencing the phases of the received echoes to the transmitted phase. A Nyquist velocity of approximately 9.7 m s–1 is obtained in real time using the spaced pulse-pair method, and aliases of radial velocities are corrected using software. The three-dimensional structure of sea fog and its advection are depicted with the radar.

A 35-GHz Scanning Doppler Radar for Fog Observations

A radar signal processing unit comprises a Fourier transform section 1 for executing Fourier transform of the received signal to a frequency signal, a frequency domain power calculation section 2 for calculating a power spectrum of electric power for each frequency from the frequency signal, an abnormal echo removal section 3 for determining the abnormal echo based on the power value of the power spectrum and outputting only the power spectrum not corresponding to the abnormal echo, an incoherent processing section 4 for performing incoherent integration of only the power spectrum not corresponding to the abnormal echo and averaging, and a signal detection section 5 for calculating the physical quantity of the atmosphere from the incoherent-integrated power spectrum.

Radar signal processing unit and radar signal processing method

PROBLEM TO BE SOLVED: To enhance a data acquiring rate in a wide altitude range SOLUTION: This processor is provided with an FFT processing part 1 for Fourier-transforming a data of a received signal, an integration time setting part 5 for setting the optimum incoherent integration time in every altitude, an incoherent integration part 2 for calculating a power spectrum based on a Fourier-transformed data to time-integrate it by the set incoherent integration time, a Doppler speed calculating part 3 for detecting a peak of a signal spectrum based on the power spectrum to calculate a sight-line-directional speed of the atmosphere based on a Doppler frequency, and a quality control and time average processing part 4 for removing a data of low quality Doppler speed to conduct time-averaging

Device and method for processing signal in wind profiler

PROBLEM TO BE SOLVED: To obtain a radar signal processing device capable of correctly measuring the Doppler velocity of an object to be observed by removing long-period topographical clutter components contained in reception signals of a Doppler radar and aircraft clutter components continuous only in a short time by a small computation amount of signal processing. SOLUTION: The radar signal processing device is provided with a higher- degree low-pass filtering means for performing higher-degree low-pass filtering processing with a long time window to reception signals, an FFT means for performing FFT processing on the output of the filtering means and outputting power spectra, and a Doppler spectrum detecting means for detecting the echo spectrum of the object to be measured from the power spectra outputted from the FFT means and computing the Doppler velocity of the object to be measured.

Radar signal processing device and method thereof

PROBLEM TO BE SOLVED: To remove only an abnormal echo generated in atmospheric observation by a radar to conduct accurately the atmospheric observation such as wind velocity measurement. SOLUTION: This processor/method is provided with a Fourier transformation part 1 for Fourier-transforming a received signal into a frequency signal, a frequency area electric power calculating part 2 for calculating a power spectrum of electric power in every frequency based on the frequency signal, an abnormal echo removing part 3 for determining the abnormal echo based on an electric power value of the power spectrum to output only the power spectrum not corresponding to the abnormal echo, an incoherent processing part 4 for incoherently integrating only the power spectrum not corresponding to the abnormal echo to be averaged, and a signal detecting part 5 for calculating a physical quantity of the atmosphere based on the incoherently integrated power spectrum. COPYRIGHT: (C)2004,JPO

Tomoya Matsuda

Papers

A 35-GHz Scanning Doppler Radar for Fog Observations

Radar signal processing unit and radar signal processing method

Device and method for processing signal in wind profiler

Radar signal processing device and method thereof

Radar signal processor, and method of processing radar signal