f3d82581-df1a-4123-b336-bdeadb80bf18 eng Ev-K2-CNR +39 035 3230511 +39 035 3230551 Via San Bernardino 145 Bergamo BG 24126 Italy metadata@evk2cnr.org http://www.evk2cnr.org/ 2012-04-01T18:17:44 ISO 19115:2003/19139 1.0 Continuous observations of synoptic-scale dust transport at the Nepal Climate Observatory-Pyramid (5079 m a.s.l.) in the Himalayas 2011-02-04T00:00:00 Atmospheric Chemistry and Physics Discuss., 11 2 4229-4261 Atmos. Chem. Phys. Discuss., 11, 4229-4261, 2011 1680-7375 This study presents two years of continuous observations of physical aerosol properties at the GAW-WMO global station "Nepal Climate Observatory – Pyramid" (NCO-P, 27°57' N, 86°48' E), sited at 5079 m a.s.l. in the high Himalayan Khumbu Valley (Nepal). Measurements of aerosol number size distribution, aerosol optical depth (AOD) and single scattering albedo (SSA) are analysed from March 2006 to February 2008. By studying the temporal variations of coarse (1 µm < Dp < 10 µm) particle number concentration, 53 mineral Dust Transport Events (DTEs) are identified, accounting for 22.2% of the analysed data-set. Such events occurred prevalently during pre-monsoon (for 30.6% of the period) and winter (22.1%) seasons. However, uncommon cases of mineral dust transport are observed even during the monsoon season. The main sources of mineral dust reaching NCO-P are identified in the arid regions not far from the measurement site, i.e. from Tibetan Plateau, and Lot-Thar deserts, which account for 52% of the dust transport days. Moreover, a non-negligible contribution can be attributed to the Arabian Peninsula (17%) and the Indo-Gangetic Plains (16%), as indicated by three dimensional (3-D) back-trajectory analyses performed with LAGRANTO model. The observed DTEs lead to significant enhancements in the coarse aerosol number concentration (+513%) and coarse aerosol mass (+655%), as compared with average values observed in "dust-free" conditions ( 0.05 ± 0.11 cm(-3) and 3.4 ± 3.7 µg m(-3), respectively). During DTEs, SSA is higher (0.84–0.89) than on "dust-free" days (0.75–0.83), confirming the importance of this class of events as a driver of the radiative features of the regional Himalayan climate. Considering the dust events, a significant seasonal AOD increase (+37.5%) is observed in the post-monsoon, whereas lower increase (less than +11.1%) characterises the pre-monsoon and winter seasons confirming the influence of synoptic-scale mineral dust transports on the aerosol optical properties observed at NCO-P. The purpose of the present paper is to evaluate and characterise the frequency and intensity of dust transport events and their influence on background atmospheric properties in the high Himalayas. The work is based on the first two years (March 2006– February 2008) of continuous observations performed at the GAW-WMO global station “Nepal Climate Observatory-Pyramid” (NCO-P) located at 5079 m a.s.l. on Southern slope of the Himalayas. The observatory is part of the Ev-K2-CNR SHARE (Stations at High Altitude for Research on the Environment) and UNEP ABC (Atmospheric Brown Clouds) projects, providing continuous measurements of trace gases, aerosol and meteorology (Bonasoni et al., 2010) Paolo Cristofanelli Institute of Atmospheric Sciences and Climate (ISAC) - CNR +39 0516399597 +39 0516399652 Via Gobetti, 101 Bologna BO 40129 Italy p.cristofanelli@isac.cnr.it www.isac.cnr.it Angela Marinoni Institute of Atmospheric Sciences and Climate (ISAC) - CNR +39 0516399597 +39 0516399652 Via Gobetti, 101 Bologna BO 40129 Italy a.marinoni@isac.cnr.it www.isac.cnr.it Paolo Bonasoni Institute of Atmospheric Sciences and Climate (ISAC) - CNR +39 0516399590 +39 0516399652 Via Gobetti, 101 Bologna BO 40129 Italy p.bonasoni@isac.cnr.it www.isac.cnr.it Francescopiero Calzolari Institute of Atmospheric Sciences and Climate (ISAC) - CNR +39 0516399582 Via Gobetti, 101 Bologna BO 40129 Italy F.Calzolari@isac.cnr.it www.isac.cnr.it Rocco Duchi Institute of Atmospheric Sciences and Climate (ISAC) - CNR +39 0516399584 Via Gobetti,101 Bologna BO 40129 Italy R.Duchi@isac.cnr.it www.isac.cnr.it Copernicus GmbH (Copernicus Publications) +49 5519003390 +49 55190033970 Bahnhofsallee 1e Göttingen 37081 Germany info@copernicus.org http://www.copernicus.org/ Paolo Laj CNRS Laboratory of Meteorology Physics - Laboratory of Glaciology +33685628874 +33473405132 Avenue des Landais Aubiere Cedex 63177 France aj@lgge.obs.ujf-grenoble.fr http://wwwobs.univ-bpclermont.fr S. Marcq CNRS Laboratory of Meteorology Physics - Laboratory of Glaciology 54, rue Molière Saint-Martin d’Hères cedex BP 96 F-38402 France http://lgge.osug.fr WWW:LINK-1.0-http--partners Paolo Villani Blaise Pascal University,CNRS +33 473405136 +33 473407678 Aubières 63177 France p.villani@opgc.univ-bpclermont.fr wwwobs.univ-bpclermont.fr WWW:LINK-1.0-http--partners Karine Sellegri Blaise Pascal University, CNRS, +33 473407394 +33 473405136 24 avenue des Landais Aubières 63177 France K.Sellegri@opgc.univ-bpclermont.fr http://wwwobs.univ-bpclermont.fr/atmos/fr/RechercheLDAP.php?nom=Sellegri&Structure=UMR6016 WWW:LINK-1.0-http--related Federico Angelini Institute of Atmospheric Sciences and Climate (ISAC) - CNR +39 0649934340 Via Fosso del Cavaliere, 100 Roma 00133 Italy F.Angelini@isac.cnr.it www.isac.cnr.it WWW:LINK-1.0-http--partners Gian Paolo Gobbi Institute of Atmospheric Sciences and Climate (ISAC) National Research Council +39 0649934343 +39 0620660291 Via Fosso del Cavaliere, 100 Roma ROMA 00133 Italy g.gobbi@isac.cnr.it www.isac.cnr.it Elisa Vuillermoz Ev-K2-CNR +39 0353230513 +39 0353230551 Via San Bernardino, 145 Bergamo BG 24126 Italy elisa.vuillermoz@evk2cnr.org http://www.evk2cnr.org WWW:LINK-1.0-http--partners Gian Pietro Verza Ev-K2-CNR Via San Bernardino, 145 Bergamo BG 24126 Italy gianpietro.verza@evk2cnr.org www.evk2cnr.org Atindra Sapkota Department of Environment Science and Engineering, Kathmandu University, +977 11661399 +977 11661443 P.O. Box 6250 Dhulikhel Kathmandu Nepal atindra@ku.edu.np http://www.ku.edu.np/env/index.php?go=atindra WWW:LINK-1.0-http--related https://geoportal.mountaingenius.org/geonetwork/srv/eng/resources.get?uuid=f3d82581-df1a-4123-b336-bdeadb80bf18&fname=mountain_witness__s.png thumbnail png SHARE GAW ABC Himalayas Nepal Climate Observatory-Pyramid Nepal dust transport single scattering albedo aerosol aerosol number size distribution aerosol optical depth Atmospheric Brown Clouds eng climatologyMeteorologyAtmosphere environment geoscientificInformation 80.0522 88.1946 26.3684 30.4247 http://www.atmos-chem-phys-discuss.net/11/4229/2011/acpd-11-4229-2011.html WWW:LINK-1.0-http--related Abstract:"Continuous observations of synoptic-scale dust transport at the Nepal Climate Observatory-Pyramid (5079 m a.s.l.) in the Himalayas" https://geoportal.mountaingenius.org/webapp/srv/en/resources.get?id=37951&fname=acpd-11-4229-2011.pdf&access=private WWW:DOWNLOAD-1.0-http--download acpd-11-4229-2011.pdf Full Text(pdf)":Continuous observations of synoptic-scale dust transport at the Nepal Climate Observatory-Pyramid (5079 m a.s.l.) in the Himalayas" "Continuous observations of synoptic-scale dust transport at the Nepal Climate Observatory - Pyramid (5079 m a.s.l.) in the Himalayas". R. Duchi, P. Cristofanelli, A. Marinoni, P. Laj, S. Marcq, P. Villani, Sellegri K.,F. Angelini, F.Calzolari, G.P. Gobbi, G.P. Verza, E. Vuillermoz, A. Sapkota, and P. Bonasoni. Atmos. Chem. Phys. Discuss., 11, 4229-4261, 2011 www.atmos-chem-phys-discuss.net/11/4229/2011/ doi:10.5194/acpd-11-4229-2011 Publication in ACP not foreseen.