Results 21 to 30 of about 492 (181)

Development and Demonstration of Navigation Doppler Lidar for Planetary Landing Missions [PDF]

EPJ Web of Conferences
A coherent Doppler lidar has been developed by NASA for providing vector velocity and altitude data to landing vehicles. Future robotic and manned missions to planetary bodies demand precise ground-relative velocity and altitude data to execute complex ...
Amzajerdian Farzin, Hines Glenn D., Gragossian Aram, Acevedo Elisa Leal, Hsu Jonathan, Laughter Sean. A., Dostart Nathan A., Heppler Jacob M., Follman Jacob J., Liles Kaitlin A.K., Martin Kimberly J., Litton Daniel. K.   +11 more
doaj   +1 more source

Wind Profiling from Boundary Layer to Stratosphere Using a Scanning Rayleigh Doppler Lidar and a Coherent Lidar

Photonics
Accurate measurements of wind fields in the troposphere and stratosphere are essential for advancing atmospheric dynamics research, improving weather prediction, and supporting aerospace operations.
Hengjia Liu, Jie Liu, Sijiang Wu, Shuhua Zhang, Jiawei Li, Chong Chen, Dongsong Sun, Yuli Han   +7 more
doaj   +1 more source

Coherent Doppler lidar for aerosol-cloud-dynamics interaction studies operating at 532.25 nm with a 3.2 GHz data acquisition [PDF]

EPJ Web of Conferences
A coherent Doppler lidar (CDL) operating at 532.25 nm wavelength with a 3.2 GHz data acquisition is developed. The technical setup is described.
Fritzsch F., Bühl J., Bollig C., Engelmann R., Wandinger U., Seifert P.   +5 more
doaj   +1 more source

Coherent Doppler Lidar for Human Motion Detection Under Dense Foliage Obscuration [PDF]

EPJ Web of Conferences
Heavily foliated environments pose challenges for aerial surveillance systems because dense tree canopy obscures the view from airborne sensors. While direct detect foliage penetrating airborne lidar systems have proven effective at locating fixed ...
Brightly Scott
doaj   +1 more source

Aircraft Wake Vortex Measurement with Airborne Coherent Doppler Lidar [PDF]

Journal of Aircraft, 2008
An experiment for airborne Doppler lidar measurement of wake vortices generated by a large transport aircraft in the free atmosphere has been successfully carried out. In this paper, the description of the experiment, data processing procedure, and measurement results are given.
Rahm, S., Smalikho, I.
openaire   +1 more source

Modeling rainfall drop size distribution moments using an S‐band polarimetric radar in complex terrain

Quarterly Journal of the Royal Meteorological Society, EarlyView.
Using S‐band dual‐polarization radar and disdrometers during PRECIP 2022 in Taiwan, we analyze a Mei‐Yu frontal event with widespread stratiform rain and embedded convection. Multiple disdrometers are used to create a novel drop size distribution model for S‐band radars resolving both the drizzle and precipitation modes. The model reveals both inferred
Ian C. Cornejo, Angela K. Rowe, Michael M. Bell, Wei‐Yu Chang   +3 more
wiley   +1 more source

Characteristics of upper‐level updrafts and downdrafts in the anvils of tropical deep convective clouds

Quarterly Journal of the Royal Meteorological Society, EarlyView.
This study investigates the thermodynamic and microphysical characteristics of updrafts and downdrafts of tropical deep convective anvil clouds using in situ measurements. We found that parts of the downdrafts are in ice supersaturation in these clouds.
Sreehari Kizhuveettil, Jordi Vila‐Guerau de Arellano, Martina Krämer, Armin Afchine, Luiz A. T. Machado, Martin Zöger, Wiebke Frey   +6 more
wiley   +1 more source

All-Fiber Airborne Coherent Doppler Lidar to Measure Wind Profiles

EPJ Web of Conferences, 2016
An all-fiber airborne pulsed coherent Doppler lidar (CDL) prototype at 1.54μm is developed to measure wind profiles in the lower troposphere layer. The all-fiber single frequency pulsed laser is operated with pulse energy of 300μJ, pulse width of 400ns ...
Liu Jiqiao, Zhu Xiaopeng, Diao Weifeng, Zhang Xin, Liu Yuan, Bi Decang, Jiang Liyuan, Shi Wei, Zhu Xiaolei, Chen Weibiao   +9 more
doaj   +1 more source

Dumpsite Seabed Characterization of the San Pedro Basin, CA, From Autonomous Vehicle Observations

Journal of Field Robotics, EarlyView.
ABSTRACT A wide‐area seabed survey was conducted using autonomous underwater vehicles (AUVs) in a known dumpsite off the coast of Southern California that has been found to have widespread sediment contamination from the chemical dichlorodiphenyltrichloroethane (DDT).
Ryan A. McCarthy, Dylan Kriegman, Sophia T. Merrifield, Heidi Batchelor, Eric J. Terrill   +4 more
wiley   +1 more source

The craters that never were: Anthropogenic origins of alleged impact structures in the Chiemgau region

Meteoritics &Planetary Science, EarlyView.
Abstract Public fascination with impact craters often drives bold speculations, but rigorous verification is critical. In southeastern Bavaria, numerous depressions have been proposed to represent impact craters associated with a catastrophic event in Celtic times (between 900 BC and 600 BC)—the so called “Chiemgau Impact.” To date, the evidence ...
Robert Huber, Hans Lauterbach, Robert Darga   +2 more
wiley   +1 more source