A magnitude and direction, or a measure responsive thereto, of a velocity (V) of a first portion (17) of an atmosphere (20) are determined from at least first and second portions of scattered light (30) generated along a common beam of light (28) within the first portion (17) of the atmosphere (20) and received along linearly independent directions at locations that are relatively remote with respect to one another, at least one of which is relatively remote from a source (11) of the beam of light (28).

Atmospheric measurement system

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 paper describes a diurnal cycle in systematic cloud system migration observed with the GMS IR1 sensor over Sumatera (approximately 1,500 km in length) from May 2001 to April 2002. Convective clouds developed over mountainous areas in the afternoon, and migrated westward and/or eastward for several hundred kilometers (∼ 500 km) from midnight to morning. Westward migration occurred in almost every month except August over southernmost Sumatera Island. Eastward migration occurred when lower-tropospheric winds were westerly and/or when super cloud clusters moved eastward along the Intertropical Convergence Zone (ITCZ), which moves northward and southward with an annual cycle.

/pdf/diurnal-cycle-of-cloud-system-migration-over-sumatera-island-4ue4dmcqp9.pdf

Diurnal cycle of cloud system migration over Sumatera Island

[1] The relationship between sunset terminators and the onset of radar backscatter plumes associated with equatorial spread F (ESF) observed with the 47-MHz Equatorial Atmosphere Radar from October 2002 to April 2004 is discussed. Almost all irregularity echoes began to appear at or before sunset time at the altitude of the apex of the geomagnetic field line connected with the observed area, and the onset time of more than half of the events corresponded exactly to apex sunset time. This tendency should be due to two causes: (1) the rapid change of the evening zonal electric field and (2) damping of 3-m scale irregularities by the solar radiation before the apex sunset.

https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2004GL021529

Relationship of the onset of equatorial F region irregularities with the sunset terminator observed with the Equatorial Atmosphere Radar

Light (32) scattered by a portion of a fluid medium (16) illuminated by a beam (18) of substantially monochromatic light (14) is received within a field-of-view (34) nominally along an axis (36) oriented in a different direction (θ) relative to the beam (18) and processed by an interferometer (44) to generate a corresponding fringe pattern (60) that is detected and processed to generate at least one measure (A, M, u, t, B, p, Ts, V, ASR, 68) of the fluid medium (16) at a plurality of different ranges (R)

Range imaging lidar

[1] A VHF Doppler radar with an active phased-array antenna system, called the Equatorial Atmosphere Radar (EAR), was established recently at the equator near Bukittinggi, West Sumatra, Indonesia (0.20°S, 100.32°E, 865 m above sea level). The EAR is a large monostatic radar which operates at 47.0 MHz with peak output power of 100 kW. The EAR uses a circular antenna array, approximately 110 m in diameter, which consists of 560 three-element Yagi antennas. Each antenna is driven by a solid-state transmitter-receiver module. This system configuration allows the antenna beam to be steered electronically up to 5,000 times per second. The scientific objective of the EAR is to advance knowledge of dynamical and electrodynamical coupling processes in the equatorial atmosphere from the near-surface region to the upper atmosphere. The equatorial atmosphere over Indonesia is considered to play an important role in global change of the Earth's atmosphere. This paper presents the system description of the EAR, including observational results of the equatorial atmosphere made for the first time with altitude resolution of 75–150 m.

/pdf/equatorial-atmosphere-radar-ear-system-description-and-first-1sedxna3ea.pdf

Equatorial Atmosphere Radar (EAR): System description and first results

We have developed a high-gain, high-peak-power laser amplifier at an eye-safe 1.55 μm wavelength using an Er,Yb:glass planar waveguide for wind sensing coherent Doppler lidars (CDLs). Our planar waveguide is free from stimulated Brillouin scattering and realizes high gain thanks to its multi-bounce optical-path configuration. A peak power of 5.5 kW with a pulse energy of 3.2 mJ is achieved at the repetition frequency of 4 kHz, which leads to an average power of 12.8 W. The gain is more than 23 dB. The wind sensing at more than 30 km is demonstrated with a CDL using the developed amplifier.

1.55-μm high-peak, high-average-power laser amplifier using an Er,Yb:glass planar waveguide for wind sensing coherent Doppler lidar.

There are included a frequency deviation determination part (12) for determining a frequency deviation (fchirp) for an optical signal; and a weight average processing part (13) for determining a system error (ΔVoffset) from the frequency deviation (fchirp) determined by the frequency deviation determination part (12); wherein the system error (ΔVoffset) is subtracted from an air velocity (VW) as calculated by a Doppler signal processing part (11). In this way, an accurate measurement of air velocity (VW) can be implemented.

Masahiro Hagio

Papers

Equatorial Atmosphere Radar (EAR): System description and first results

1.55-μm high-peak, high-average-power laser amplifier using an Er,Yb:glass planar waveguide for wind sensing coherent Doppler lidar.

Lightwave radar apparatus

Windshear detection by Terminal Doppler Weather Radar during Tropical Cyclone Mujigae in 2015