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Pollen allergenicity plays an important role on human health and wellness. It is thus of large public interest to increase our knowledge of pollen grain behavior in the atmosphere (source, emission, processes involved during their transport, etc.) at fine temporal and spatial scales. First simulations with the Barcelona Supercomputing Center NMMB/BSC-CTM model of Platanus and Pinus dispersion in the atmosphere were performed during a 5-day pollination event observed in Barcelona, Spain, between 27 – 31 March, 2015. The simulations are compared to vertical profiles measured with the continuous Barcelona Micro Pulse Lidar system. First results show that the vertical distribution is well reproduced by the model in shape, but not in intensity, the model largely underestimating in the afternoon. Guidelines are proposed to improve the dispersion of airborne pollen by numerical prediction models., Lidar data analysis were supported by the ACTRIS (Aerosols, Clouds, and Trace Gases Research Infrastructure Network) Research Infrastructure Project funded by the European Union’s Horizon 2020 research and innovation programme under grant agreement n. 654169; by the Spanish Ministry of Economy and Competitivity (project TEC2015-63832-P) and of Science and Innovation (project UNPC10-4E-442) and EFRD (European Fund for Regional Development); by the Department of Economy and Knowledge of the Catalan autonomous government (grant 2014 SGR 583). This work is contributing to the ICTA 'Unit of Excellence' (Spanish Ministry of Economy and Competitivity, project MDM2015-0552)., Postprint (published version)

Accurate continuous measurements of relative humidity (RH) vertical profiles in the lower troposphere have become a significant scientific challenge. In recent years a synergy of various ground-based remote sensing instruments have been successfully used for RH vertical profiling, which has resulted in the improvement of spatial resolution and, in some cases, of the accuracy of the measurement. Some studies have also suggested the use of high-resolution model simulations as input datasets into RH vertical profiling techniques. In this paper we apply two synergetic methods for RH profiling, including the synergy of lidar with a microwave radiometer and high-resolution atmospheric modeling. The two methods are employed for RH retrieval between 100 and 6000ĝ€m with increased spatial resolution, based on datasets from the HygrA-CD (Hygroscopic Aerosols to Cloud Droplets) campaign conducted in Athens, Greece from May to June 2014. RH profiles from synergetic methods are then compared with those retrieved using single instruments or as simulated by high-resolution models. Our proposed technique for RH profiling provides improved statistical agreement with reference to radiosoundings by 27ĝ€% when the lidar-radiometer (in comparison with radiometer measurements) approach is used and by 15ĝ€% when a lidar model is used (in comparison with WRF-model simulations). Mean uncertainty of RH due to temperature bias in RH profiling was ĝ1/4 4.34ĝ€% for the lidar-radiometer and ĝ1/4 1.22ĝ€% for the lidar-model methods. However, maximum uncertainty in RH retrievals due to temperature bias showed that lidar-model method is more reliable at heights greater than 2000ĝ€m. Overall, our results have demonstrated the capability of both combined methods for daytime measurements in heights between 100 and 6000ĝ€m when lidar-radiometer or lidar-WRF combined datasets are available., Atmospheric Remote Sensing

Accurate continuous measurements of relative humidity (RH) vertical profiles in the lower troposphere have become a significant scientific challenge. In recent years a synergy of various ground-based remote sensing instruments have been successfully used for RH vertical profiling, which has resulted in the improvement of spatial resolution and, in some cases, of the accuracy of the measurement. Some studies have also suggested the use of high-resolution model simulations as input datasets into RH vertical profiling techniques. In this paper we apply two synergetic methods for RH profiling, including the synergy of lidar with a microwave radiometer and high-resolution atmospheric modeling. The two methods are employed for RH retrieval between 100 and 6000 m with increased spatial resolution, based on datasets from the HygrA-CD (Hygroscopic Aerosols to Cloud Droplets) campaign conducted in Athens, Greece from May to June 2014. RH profiles from synergetic methods are then compared with those retrieved using single instruments or as simulated by high-resolution models. Our proposed technique for RH profiling provides improved statistical agreement with reference to radiosoundings by 27 % when the lidar–radiometer (in comparison with radiometer measurements) approach is used and by 15 % when a lidar model is used (in comparison with WRF-model simulations). Mean uncertainty of RH due to temperature bias in RH profiling was ∼ 4.34 % for the lidar–radiometer and ∼ 1.22 % for the lidar–model methods. However, maximum uncertainty in RH retrievals due to temperature bias showed that lidar-model method is more reliable at heights greater than 2000 m. Overall, our results have demonstrated the capability of both combined methods for daytime measurements in heights between 100 and 6000 m when lidar–radiometer or lidar–WRF combined datasets are available., The authors thank the ITaRS program for generous support. The research leading to this article has received funding from the European Community’s FP7 – PEOPLE 2011 under grant agreement number 289923 – ITARS (Initial Training for Atmospheric Remote Sensing) and has also been supported by the National Core Program – PN 16.40.01.01/2017 and ROSA – STAR project CARESSE. All WRF simulations were performed on the MareNostrum supercomputer hosted by the Barcelona Supercomputing Center (BSC). We acknowledge the project CGL2013- 46736-R, and the Severo Ochoa Programme awarded by the Spanish Government (SEV-2011-00067) and 2014 SGR 522. Additionally, the research leading to these results has received funding from the European Union’s Horizon 2020 Research and Innovation programme under grant agreement no. 602014, project ECARS (East European Centre for Atmospheric Remote Sensing). The Hellenic National Meteorological Service (HNMS) is acknowledged for performing the high-resolution radiosoundings. We acknowledge the team from the University of Cologne for the microwave radiometer calibration and installation the HygrA-CD campaign. The financial support of the ACTRIS Research Infrastructure Project by the European Union’s Horizon 2020 – Research and Innovation Framework Programme, under grant agreement no. 654169 is gratefully acknowledged. The topical editor, Vassiliki Kotroni, thanks two anonymous referees for help in evaluating this paper., Peer Reviewed, Postprint (published version)

Here we analyze the impact of four planetary boundary-layer (PBL) parametrization schemes from the Weather Research and Forecasting (WRF) numerical weather prediction model on simulations of meteorological variables and predicted pollutant concentrations from an air quality forecast system (AQFS). The current setup of the Spanish operational AQFS, CALIOPE, is composed of the WRF-ARW V3.5.1 meteorological model tied to the Yonsei University (YSU) PBL scheme, HERMES v2 emissions model, CMAQ V5.0.2 chemical transport model, and dust outputs from BSC-DREAM8bv2. We test the performance of the YSU scheme against the Assymetric Convective Model Version 2 (ACM2), Mellor-Yamada-Janjic (MYJ), and Bougeault-Lacarrère (BouLac) schemes. The one-day diagnostic case study is selected to represent the most frequent synoptic condition in the northeast Iberian Peninsula during spring 2015; regional recirculations. It is shown that the ACM2 PBL scheme performs well with daytime PBL height, as validated against estimates retrieved using a micro-pulse lidar system (mean bias = − 0.11 km). In turn, the BouLac scheme showed WRF-simulated air and dew point temperature closer to METAR surface meteorological observations. Results are more ambiguous when simulated pollutant concentrations from CMAQ are validated against network urban, suburban, and rural background stations. The ACM2 scheme showed the lowest mean bias (− 0.96 μg m− 3) with respect to surface ozone at urban stations, while the YSU scheme performed best with simulated nitrogen dioxide (− 6.48 μg m− 3). The poorest results were with simulated particulate matter, with similar results found with all schemes tested., The research leading to these results has received funding from the European Union Seventh Framework Programme (FP7/2007-2013): People, ITN Marie Curie Actions Programme (2012–2016) in the frame of ITaRS under grant agreement no. 289923. Simulations were executed on the MareNostrum supercomputer at the Barcelona Supercomputing Centre, under grants SEV-2011-00067 of Severo Ochoa program and CGL2013-46736-R, awardedby theSpanish Government.Specialthanks to Francesc Rocadenbosch and the UPC Remote Sensing Laboratory for use of the extended Kalman filter technique. The authors wish to thank Victor Valverde for his assistance with the air quality simulations., Peer Reviewed, Postprint (author's final draft)

The present work demonstrates the impact of model resolution in dust propagation in a complex terrain region such as West Asia. For this purpose, two simulations using the NMMB/BSC-Dust model are performed and analysed, one with a high horizontal resolution (at 0.03° × 0.03°) and one with a lower horizontal resolution (at 0.33° × 0.33°). Both model experiments cover two intense dust storms that occurred on 17–20 March 2012 as a consequence of strong northwesterly Shamal winds that spanned over thousands of kilometres in West Asia. The comparison with ground-based (surface weather stations and sunphotometers) and satellite aerosol observations (Aqua/MODIS and MSG/SEVIRI) shows that despite differences in the magnitude of the simulated dust concentrations, the model is able to reproduce these two dust outbreaks. Differences between both simulations on the dust spread rise on regional dust transport areas in south-western Saudi Arabia, Yemen and Oman. The complex orography in south-western Saudi Arabia, Yemen and Oman (with peaks higher than 3000 m) has an impact on the transported dust concentration fields over mountain regions. Differences between both model configurations are mainly associated to the channelization of the dust flow through valleys and the differences in the modelled altitude of the mountains that alters the meteorology and blocks the dust fronts limiting the dust transport. These results demonstrate how the dust prediction in the vicinity of complex terrains improves using high-horizontal resolution simulations., We would like to acknowledge the AERONET and PHOTONS networks, which kindly provided their data, and the research groups that contribute to the networks. We also acknowledge the MSG and MODIS mission scientists and associated EUMETSAT and NASA personnel for the production of the data used in this research effort. S. Basart acknowledges the CICYT project (CGL2013-46736) and L. Vendrell acknowledges La Caixa foundation. The authors would like to special thank Dr. Oriol Jorba and Dr. Enza Di Tomaso for comments on the manuscript and K. Serradell and F. Benincasa for the technical support. All simulations were performed on the MareNostrum supercomputer hosted by BSC., Peer Reviewed, Postprint (published version)