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A Rayleigh scattering lidar for measuring the atmospheric density and temperature has been deployed at Zhongshan Station (69.4° S, 76.4° E), Antarctica. Lidar transmitter was a frequency doubled Nd:YAG laser with ~400 mJ pulse energy and 30 Hz repetition rate. A telescope with 0.8 m diameter pointing to the zenith direction served as the lidar receiver. This lidar was capable of profiling the density and temperature in the Upper Stratosphere and Lower Mesosphere (USLM) region. At the vertical resolution of 300 m and the temporal resolution of 30 min, the lidar measurement uncertainties, mainly due to the photon noise, were calculated to be within 1.5% and 1 K for density and temperature, respectively. Since March 2020, this lidar has been routinely operated at Zhongshan station for exploring the atmospheric density and temperature variations and wave propagation characteristics in the polar USLM region.

Temperature is an important parameter in describing the atmospheric state. Large-scale temperature profile measurements with high temporal and vertical resolutions can provide a comprehensive understanding of the atmospheric dynamics and thermodynamics. Different from Rayleigh mechanism, a pure rotational Raman (PRR) lidar is preferred for the lower atmospheric temperature measurements even with the aerosol and optically cloud layers.

A new multi-wavelength canopy LiDAR (MWCL) system intended for the remote sensing of vegetation reflection was designed and its measurement performance was investigated. The system operates with four lasers of different wavelengths chosen according to nitrogen stresses that induce changes in the optical properties and spectral reflectance of rice leaves. The optical design and instrumentation are described in this paper as well as a discussion on system calibration. The MWCL system was demonstrated to possess a high capability of recording the physiology of the canopy, which is not possible when solely employing a traditional single-wavelength LiDAR. Crown Copyright (C) 2012 Published by Elsevier B.V. on behalf of Society. All rights reserved.

A temperature-insensitive edge laser frequency stabilization method with an acousto-optic modulator (AOM) was proposed and demonstrated both theoretically and experimentally in this Letter. In the method, in addition to the unshifted laser frequency, two other shifted frequencies were generated by the AOM. The intensity ratio of these two shifted frequencies was used to stabilize the laser. As the intensity ratio was nearly constant despite the temperature change, the proposed method was temperature insensitive. The theoretical and experimental results showed that the frequency drift of a stabilized laser induced by temperature change was reduced by more than 2 orders of magnitude by using the proposed method when compared with traditional frequency stabilization without an AOM.

We report on a sporadic sodium layer (SSL) event observed by our Na fluorescence lidar at Wuhan, China (31degreesN, 114degreesE) on 16 March 1999, and we reveal some special behaviour. From careful analysis of various sodium content variations of the layer during the development of this SSL event, it is found that besides the sodium injection mechanism as expected, another mechanism which we call atmospheric dynamics also made a noticeable contribution to this SSL formation. Computer simulations confirmed that under the combined action of a suitable sodium injection and a bi-direction vertical wind field, an SSL profile can be reproduced with a pronounced SSL peak on a normal sodium layer, as we observed in this event. From these results, it is emphasized that atmospheric dynamics is important for SSL formation.

A multipurpose Lidar was built at Wuhan Institute of Physics & Mathematics, Chinese Academy of Science. The Lidar consists of an YAG laser pumped dye laser system, two receiving telescopes and several detection channels. During the past few years, we conducted some lidar observation in various altitudes of the atmosphere at our location. In this paper, we describe the technical aspects of this multipurpose lidar, and summarize some of the atmosphere observation results obtained by the lidar over Wuhan, China (31 deg N,114 deg E) with the emphasis on the sodium layer detections.

Full list of authors: Erdélyi, Robertus; Korsós, Marianna B.; Huang, Xin; Yang, Yong; Pizzey, Danielle; Wrathmall, Steven A.; Hughes, Ifan G.; Dyer, Martin J.; Dhillon, Vikram S.; Belucz, Bernadett; Brajša, Roman; Chatterjee, Piyali; Cheng, Xuewu; Deng, Yuanyong; Domínguez, Santiago Vargas; Joya, Raúl; Gömöry, Peter; Gyenge, Norbert G.; Hanslmeier, Arnold; Kucera, Ales; Kuridze, David; Li, Faquan; Liu, Zhong; Xu, Long; Mathioudakis, Mihalis; Matthews, Sarah; McAteer, James R. T.; Pevtsov, Alexei A.; Pötzi, Werner; Romano, Paolo; Shen, Jinhua; Temesváry, János; Tlatov, Andrey G.; Triana, Charles; Utz, Dominik; Veronig, Astrid M.; Wang, Yuming; Yan, Yihua; Zaqarashvili, Teimuraz; Zuccarello, Francesca.--This is an Open Access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited., The Solar Activity Magnetic Monitor (SAMM) Network (SAMNet) is a future UK-led international network of ground-based solar telescope stations. SAMNet, at its full capacity, will continuously monitor the Sun’s intensity, magnetic, and Doppler velocity fields at multiple heights in the solar atmosphere (from photosphere to upper chromosphere). Each SAMM sentinel will be equipped with a cluster of identical telescopes each with a different magneto-optical filter (MOFs) to take observations in K I, Na D, and Ca I spectral bands. A subset of SAMM stations will have white-light coronagraphs and emission line coronal spectropolarimeters. The objectives of SAMNet are to provide observational data for space weather research and forecast. The goal is to achieve an operationally sufficient lead time of e.g., flare warning of 2–8 h and provide many sought-after continuous synoptic maps (e.g., LoS magnetic and velocity fields, intensity) of the lower solar atmosphere with a spatial resolution limited only by seeing or diffraction limit, and with a cadence of 10 min. The individual SAMM sentinels will be connected to their master HQ hub where data received from all the slave stations will be automatically processed and flare warning issued up to 26 h in advance. © R. Erdélyi et al., Published by EDP Sciences 2022., RE is grateful to the Science and Technology Facilities Council (STFC, grant numbers ST/M000826/1 and ST/V005979/1) the UK and the Royal Society for enabling this research. RE also acknowledges the CAS Presidents International Fellowship Initiative, Grant No. 2019VMA052 and the TOP CLLD 7.1.1-16-H-ERFA-2019-00207-Magyar Napfizikai Alaptvány ID Nr 1-8-2019/P support.MBK acknowledges STFC grant ST/S000518/1 to Aberystwyth University. MBK also acknowledges the open research program of CAS Key Laboratory of Solar Activity, National Astronomical Observatories, No. KLSA201610. RE and MBK both acknowledge the CAS Key Laboratory of Solar Activity, National Astronomical Observatories Commission for Collaborating Research Program for the support received to carry out part of this work. IGH and DP acknowledge support from EPSRC (grant EP/R002061/1). RB acknowledges the support by the Croatian Science Foundation under project 7549 “Millimeter and submillimeter observations of the solar chromosphere with ALMA”. RB, AH, and AMV acknowledge the support from the Austrian-Croatian Bilateral Scientific Project “Comparison of ALMA observations with MHD-simulations of coronal waves interacting with coronal holes”. AK and PG acknowledge the support from grant VEGA 2/0048/20. AAP acknowledges NASA 80NSSC18K1242 grant and grant No. 19-02-00088 by RFBR. Sunspot Solar Observatory is a partnership between NSF (1945705), the National Solar Observatory, the state of New Mexico, and consortium partners. TZ acknowledges funding from the Austrian Science Fund (FWF, project P30695-N27). FZ acknowledges support by the Università degli Studi di Catania (Piano per la Ricerca Università di Catania 2016–2018 – Linea di intervento 1 “Chance”; Linea di intervento 2 “Dotazione ordinaria”; Fondi di Ateneo 2020–2022, Università di Catania, Linea Open Access), by the Italian MIUR-PRIN grant 2017APKP7T on “Circumterrestrial Environment: Impact of Sun-Earth Interaction”. YH acknowledges funding from NSFC (11790300,11790301). DK has received funding from the Sêr Cymru II scheme, part-funded by the European Regional Development Fund through the Welsh Government. © R. Erdélyi et al., Published by EDP Sciences 2022., With funding from the Spanish government through the Severo Ochoa Centre of Excellence accreditation SEV-2017-0709.