Simultaneous observations of boundary-layer aerosol layers with CL31 ceilometer and 1064/532 nm lidar

McKendry, Ian G.; Kamp, D. van der; Strawbridge, K. B.; Christen, Andreas; Crawford, Ben

doi:10.1016/j.atmosenv.2009.07.063

Cited by 41 publications

(38 citation statements)

References 14 publications

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“…The profile of attenuated backscattering coefficients in the atmosphere can be analyzed to determine the location of sudden changes caused by variations in the attenuated backscattering coefficients, which is at the top of the atmospheric mixing layer. The lidar ceilometer is inexpensive and convenient and has been widely applied in observations of the mixing-layer height (Sicard et al, 2006;Münkel et al, 2007;McKendry et al, 2009;Emeis et al, 2012;Yang et al, 2013;Pandolfi et al, 2013;Schween et al, 2014;Scarino et al, 2014). In this study, the gradient method was used to identify the mixing-layer height, and maximum negative gradient value (−dβ/dx) of the attenuated backscattering coefficient profile was at the top of the mixing layer (Michael et al, 2006;Emeis et al, 2012).…”

Section: Calculation Of Mixing-layer Heightmentioning

confidence: 99%

Impact of emission controls on air quality in Beijing during APEC 2014: lidar ceilometer observations

et al. 2015

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Abstract. The implementation of emission reductions during the 2014 Asia-Pacific Economic Cooperation (APEC) summit provides a valuable opportunity to study air pollution in Beijing. From 15 October to 30 November 2014, the height of the atmospheric mixing layer and the vertical attenuated backscattering coefficient profiles were observed online using a lidar ceilometer. Compared with fine particulate matter (PM 2.5 ) and aerosol optical depth (AOD) data, the attenuated backscattering coefficients measured by the lidar ceilometer were strongly correlated with the PM 2.5 concentration and AOD (correlation coefficients of 0.89 and 0.86, respectively). This result demonstrated the reliability of the vertical distribution of particles measured by the lidar ceilometer. By classifying different degrees of air pollution based on visibility, we found that during the transition period of air pollution, which was affected by transport of southerly flows in the mixing layer, the attenuated backscattering coefficient from 0 to 1500 m was enhanced by approximately 1.4 Mm −1 sr −1 (140 %). During the polluted period, the attenuated backscattering coefficient from 0 to 300 m suddenly increased, and the coefficient near the surface peaked (approximately 14 Mm −1 sr −1 ); however, the attenuated backscattering coefficient from 300 to 900 m decreased gradually, and the average value from 0 to 1500 m decreased by 0.5 Mm −1 sr −1 (20 %). The height of the mixing layer gradually decreased, and the ratio of CO / SO 2 gradually increased, which indicate that the polluted period was dominated by local contribution. Due to the emission reductions during APEC (DAPEC), the concentration of PM 2.5 decreased by 59.2 and 58.9 % and visibility improved by 70.2 and 56.0 % compared to before (BAPEC) and after APEC (AAPEC), respectively. The contribution of regional transport in DAPEC decreased by approximately 36 and 25 %, and the local contribution decreased by approximately 48 and 54 % compared to BAPEC and AAPEC, respectively. The most effective method of controlling air pollution in the Beijing area is to reduce regional emissions during the transition period and reduce local emissions during the polluted period.

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Section: Calculation Of Mixing-layer Heightmentioning

confidence: 99%

Impact of emission controls on air quality in Beijing during APEC 2014: lidar ceilometer observations

et al. 2015

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“…Apart from a few occasions (e.g., André and Mahrt, 1982;Berman et al, 1999;Day et al, 2010), NSL measurements are particularly uncommon since most radiosonde launches are performed during daytime ML hours. In recent years, remote-sensing techniques such as light detection and ranging (lidar), radio acoustic sounding systems (RASS), and sonic detection and ranging (sodar) systems have allowed for the continuous monitoring of the BL (Cohn and Angevine, 2000;Schäfer et al, 2011;Seibert et al, 2000;Emeis et al, 2004Emeis et al, , 2006Emeis et al, , 2012Eresmaa et al, 2006;Baars et al, 2008;McKendry et al, 2009;Muñoz and Undurraga, 2010;Haman et al, 2012;Milroy et al, 2012;Compton et al, 2013;Scarino et al, 2014;Wiegner and Gasteiger, 2015;Uzan et al, 2016). Ceilometers in particular offer a low-maintenance and low-cost solution to constantly monitoring the ML using aerosol backscatter while also facilitating the monitoring of the nocturnal stable layer, internal aerosol layers, and the nighttime residual layer (Haman et al, 2012Pandolfi et al, 2013;Peña et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

Comparison of aerosol lidar retrieval methods for boundary layer height detection using ceilometer aerosol backscatter data

Caicedo

Rappenglück

Lefer³

et al. 2017

Atmos. Meas. Tech.

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Abstract. Three algorithms for estimating the boundary layer heights are assessed: an aerosol gradient method, a cluster analysis method, and a Haar wavelet method. Over 40 daytime clear-sky radiosonde profiles are used to compare aerosol backscatter boundary layer heights retrieved by a Vaisala CL31 ceilometer. Overall good agreement between radiosonde-and aerosol-derived boundary layer heights was found for all methods. The cluster method was found to be particularly sensitive to noise in ceilometer signals and lofted aerosol layers (48.8 % of comparisons), while the gradient method showed limitations in low-aerosol-backscatter conditions. The Haar wavelet method was demonstrated to be the most robust, only showing limitations in 22.5 % of all observations. Occasional differences between thermodynamically and aerosol-derived boundary layer heights were observed.

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“…This is the subject of further investigation, but we propose that this effect may, in many cases, be associated with the onshore advection of cleaner air and lower MLHs with sea breeze onset. In addition, the 15 April example (a) demonstrates the feasibility of using the 1064/532 nm CORALNet lidar to detect boundary layer structure and MLH height at high resolution, (b) confirms the presence of elevated nocturnal pollution layers, and (c) suggests the potential for spatial analyses of boundary layer processes based on a network of lidars and ceilometers (as discussed by McKendry et al (2009)). …”

Section: Background a Geography And Meteorologymentioning

confidence: 91%

“…The height of the boundary layer, for both the daytime convective and the nocturnal stable cases, is a parameter with important air quality implications. Previous studies, based primarily on intensive observation periods, have revealed spatial patterns in boundary layer depths over the Lower Fraser Valley (Steyn, 1980;Strawbridge and Snyder, 2004;Batchvarova et al, 1999) as well as identifying the importance of elevated layer structures over the region Maletto et al, 2003;McKendry and Lundgren, 2000;McKendry et al, 2009). Detection of daytime mixed layer height (MLH) by lidar is dependent on there being sufficient aerosol in the boundary layer to be able to distinguish the mixed layer from the free troposphere.…”

Section: Background a Geography And Meteorologymentioning

confidence: 99%

“…Rich datasets produced by these systems provide opportunities to study myriad phenomena at a range of scales. Examples include the detection of boundary layer height and structure (Baars et al, 2008;Brooks et al, 2003;McKendry et al, 2009;Morille et al, 2007;Steyn et al, 1999) and cloud base (Morille et al, 2007;Pal et al, 1992;Wang and Sassen, 2001) and, with Raman Lidar, the structure of frontal systems (Melfi et al, 1989;Sakai et al, 2005) and gravity waves (Rauth et al, 2008). Lidar can also *Corresponding author's e-mail: ian.mckendry@geog.ubc.ca elucidate singular events such as dust storms, biomass burning plumes and even firework plumes (Müller et al, 2005;van der Kamp et al, 2008;Tratt et al, 2001;Murayama et al, 2001).…”

Section: Introductionmentioning

confidence: 99%

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Continuous 1064/532 nm Lidar Measurements (CORALNet-UBC) in Vancouver, British Columbia: Selected Results from a Year of Operation

2011

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CORALNet-UBC was installed in April 2008 as a "proof of concept" and the first facility in a proposed cross-Canada network of similar lidars. Despite its location on the wet West Coast of Canada, data recovery ranged from a low of 45% of the total time in December, when heavy snowfall interrupted operations, to a high of 90% in July. The facility has been a spectacular success in terms of its operational characteristics (as measured by data recovery), the range of phenomena observed and the research that it has spawned. Examples are provided of the types of phenomena observed since its initial deployment. These include observations of boundary layer structure, cloud signatures, forest fire plumes and evidence of singular long-range pollutant and volcanic transport events. Observations from CORALNet-UBC complement data from other aerosol measurement initiatives in the region and provide a rich source of information that is relevant to researchers, operational forecasters and air quality managers. Future research will be directed at elucidating the processes and phenomena revealed by the instrument as well as developing new products that exploit the real-time forecasting and public advisory potential of the facility. RÉSUMÉ[Traduit par la rédaction] Le lidar CORALNet-UBC a été installé en avril 2008 comme une « démon-stration de faisabilité » et constitue le premier élément d'un réseau de lidars semblables proposé pour couvrir le Canada. Malgré son emplacement sur la pluvieuse côte ouest du Canada, la récupération des données a varié d'un minimum de 45 % du temps total en décembre, alors que de fortes chutes de neige ont interrompu les opérations, à un maximum de 90 % en juillet. L'installation s'est avérée un succès spectaculaire du point de vue de ses caractéristiques d'exploitation (telles que mesurées par la récupération des données), de la gamme des phénomènes observés et de la recherche qu'elle a engendrée. Nous présentons des exemples des types de phénomènes observés depuis sa mise en place initiale. Ceux-ci comprennent des observations de la structure de la couche limite, de signatures de nuages, de panaches de feux de forêt et de manifestations d'événements singuliers de transport de polluants et de cendre volcanique à grande distance. Les observations du CORALNet-UBC s'ajoutent aux données d'autres projets de mesure d'aérosols dans la région et fournissent une riche source d'information utile pour les chercheurs, les prévisionnistes opérationnels et les gestionnaires de la qualité de l'air. Les recherches futures viseront à élucider les processus et les phénomènes que révèle l'instrument ainsi qu'à mettre au point de nouveaux produits permettant de tirer profit des capacités de l'installation en ce qui a trait à la prévision en temps réel et à l'émission d'avis pour le public.

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Simultaneous observations of boundary-layer aerosol layers with CL31 ceilometer and 1064/532 nm lidar

Cited by 41 publications

References 14 publications

Impact of emission controls on air quality in Beijing during APEC 2014: lidar ceilometer observations

Impact of emission controls on air quality in Beijing during APEC 2014: lidar ceilometer observations

Comparison of aerosol lidar retrieval methods for boundary layer height detection using ceilometer aerosol backscatter data

Continuous 1064/532 nm Lidar Measurements (CORALNet-UBC) in Vancouver, British Columbia: Selected Results from a Year of Operation

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