AtmoHEAD 2014: <br> Atmospheric Monitoring for High Energy AstroParticle Detectors

19 May 2014, 11:00 → 21 May 2014, 17:30 Europe/Rome

Aula Nievo (Palazzo del Bo)

The atmosphere is an integral component of imaging atmospheric Cherenkov telescopes (IACTs) and cosmic-ray extensive air shower detectors, the two instruments driving the quickly evolving fields of VHE and UHE astrophysics. In these fields, the atmosphere is used as a giant calorimeter where EASs are initiated and the medium through which Cherenkov light propagates. Uncertainty in current atmospheric conditions and fixed atmospheric models results in a dominant source of systematic errors. With the improved sensitivity of future facilities like CTA, HAWC or for satellite experiments like JEM-EUSO, statistical uncertainties will be reduced, leaving the atmosphere as the limiting factor in the determination of gamma-ray source spectra. Unstable weather conditions necessitate the development of atmospheric monitoring as part of the instrument calibration.

This is the second conference of the Atmohead series, initiated in 2013 in Saclay (Paris, France) with a very successful workshop. For this edition, we foresee to have contributions from experts in the fields coming from non-astronomical communities, as well as contribution from interested companies working in the field.
 

 

Main sessions in the conference:
1. Highlights talks
2. Overview on atmospheric calibration solutions for current and planned experiments 
3. Details on instruments and methods 
4. Companies

The conference has a fee of 50 euros to be paid in cash at the registration desk.

 

Scientific Committee:
Carla Aramo (INFN-NA, Italy),
Gionata Biavati (MPI-BGC, Germany)
Ryan Chaves (LUPM, CNRS/IN2P3, France),  
Michael Daniel (Univ. Liverpool, UK)
Michele Doro (INFN-PD, Italy),
Markus Gaug (UAB, Spain),
Karim Louedec (LPSC, CNRS/IN2P3, France), 
Raquel de Los Reyes (MPI-K, Germany),
Aurelio Tonachini (INFN-TO, Italy),
Martin Will (IAC, Spain)

Local organising Committee:
Michele Doro
Giovanni Busetto
Mose' Mariotti
Rossella Spiga

Secretaries: Paola Zenere

Sponsored by: CAEN Tools for Discovery

Leaflet Bo Palace English VisiteBOeng_DEF11.pdf

Leaflet Bo Palace French VisiteBOfra_DEFBassa.pdf

Leaflet Bo Palace German VisiteBOdeut_DEF11.pdf

Leaflet Bo Palace Italian VisiteBOita_DEF11.pdf

Leaflet Bo Palace Spanish VisiteBOesp_DEF11.pdf

Poster poster_atmohead.pdf

Monday, 19 May

Registration

13:00 Lunch Break

Highlights

Convener: Michele Doro (PD)

1 Welcome

Speaker: Michele Doro (PD)

Slides doro_intro.pptx

2 Atmospheric Characterization of Sites

Speaker: Prof. Sergio Ortolani

Slides Ortolani_cta_conference2014c.pdf

3 Climate Changes

Speaker: Alessio Bellucci (CMCC)

Slides ATMOHEAD_Bellucci_Padova_May2014.ppt

4 The Innsbruck / ESO Sky Models and Telluric Correction Tools

A large fraction of uncertainty for the interpretation of data from imaging Cerenkov telescopes originates from the use of static average atmosphere models. We present an alternative approach to this issue. As part of the entrance fee to the European Southern Observatory (ESO) Austrian universities developed software modules for various projects, called in-kind projects, dealing with the effect of the Earth's atmosphere on ground-based astronomical observations. The Innsbruck team (http://www.uibk.ac.at/eso) has provided tools to calculate this influence of the atmosphere for the astronomical community (https://www.eso.org/observing/etc/skycalc/skycalc.htm; Noll et al. 2012, A&A, 543, A92, Kausch et al. 2014, arXiv, 1401.7768). In the framework of the follow up programs, the team now extends the applications to geoscience (Jones et al. 2013, EGUGA, 15, 8478; Kausch et al. 2013, EGUGA, 15, 7425), and other astronomical fields. In particular, the adaption of these tools to air shower experiments looks promising. The software is based on the radiative transfer code LBLRTM (http://rtweb.aer.com/lblrtm.html) for molecular absorption and our own elaborate code aimed for calculating the scattering of the continuum (including local sources e.g. ground reflection). For information on the molecular line parameters, the HITRAN data base (http://www.cfa.harvard.edu/hitran) is used. In addition, atmospheric profiles based on a standard atmosphere and the Global Data Assimilation System (GDAS) weather models obtained from the National Climatic Data Center (NOAA; http://www.ncdc.noaa.gov/) are incorporated. We also compared our results with data obtained with the Low Humidity and Temperature Profiling microwave radiometer (LHATPRO; for details see Kerber et al. 2014, doi:10.1093/mnras/stt2404) profiles. Recently, dedicated observations of scattered moonlight with the ESO VLT have been taken to study aerosol scattering in more detail (Jones et al. 2013, A&A, 560, A91; 2014, in prep). The ESO site at Cerro Paranal was perfect for the study, as it provides many different sources of information to improve the model, e.g. local meteorological information, as well as radiometer data, and high resolution astronomical spectra containing the finger print of the state of the Earth’s atmosphere. Although these investigations are based on Cerro Paranal data, the deep understanding of the connection between the GDAS models and local calibrators can also be applied everywhere. Imaging atmospheric Cherenkov telescopes like MAGIC and HESS are dominated by the effects of the lower 10km of the atmosphere and are working at the very blue end of the spectrum until the ozone absorption. Recently, the molecular data base HITRAN was extended into this blue domain. The talk shows the status of the current research and the existing tools and discusses how information from various other calibrators (stars, radiometers, …) can be included into the model optimisation. Furthermore, we discuss how radiation generated in the lower atmosphere can be handled. This opens the discussion about which adaption of such models, originally designed for optical/IR light sources from outer space, can be applied in the case of the atmospheric Cherenkov telescopes and which kind of calibrators are useful to obtain better results than general static profiles mostly used up to now in the astro-particle community.

Speaker: Mr Stefan Kimeswenger (Universidad Catolica del Norte, Antofagasta, Chile / University Innsbruck, Austria)

Slides Kimeswenger_padova_19_4_2014.pdf

16:30 Coffee Break

5 Science and More with Lasers and Astroparticle Observatories

Between the experiments in operation, including Auger and Telescope array, planned upgrades to Auger and TA, and activities in progress to realize JEM-EUSO and CTA, there is a growing interest in the design and applications of laser systems for optical astroparticle observatories. There are no particle test beams at EeV energies. Laser systems placed in the field have a history of providing a cost-effective and practical alternative. The bistatic lidar arrangement in which the astroparticle detector is the receiver, offers the opportunity to explore a variety of techniques and measurements. Some of these, various practical and design considerations will be the topic of this presentation.

Speaker: Prof. Lawrence Wiencke (Colorado School of Mines)

Slides Wiencke_AtmoHEAD_2014.pdf

6 Multi-wavelength polarization Lidar characterization of mineral dust at Dunhuang (China)

Xuan Wang1, Antonella Boselli2 , Alessia Sannino3 , Nicola Spinelli3 , Yiming Zhao4,, Song Changbo4 CNISM& BRIT - China-Italy Laser Remote Sensing Joint Research Center and 1CNR-SPIN, Napoli, Italy 2CNR-IMAA, Napoli, Italy 3Dipartimento di Fisica, Università di Napoli “Federico II”, Napoli, Italy 4Beijing Research Institute for Telemetry, Beijing, P.R. China The Gobi desert is the major source of mineral dust in China, that is one of the most interesting regions for aerosol study being surrounded by the main sources of anthropogenic and natural aerosol. In order to characterize the chemical and physical properties of atmospheric aerosols, their spatial and temporal distribution and the main transport mechanisms a new, versatile and portable Raman scanning lidar system has been designed and developed at Physics Department of University of Napoli “Federico II” in the frame of the AMPLE project, the first action of the recently founded China-Italy Laser Remote Sensing Joint Research Center between the National Consortium of Italian Universities for the Physical Science of the Matter (CNISM) and the Beijing Research Institute for Telemetry (BRIT). A first demonstrative measurement campaign has been performed on May 2013 in Beijing, while on August 2013 AMPLE has been carried in Dunhuang close to the Gobi desert and far away from the urban area, in order to study sand dust directly at source. Results of those measurements will be described.

Speaker: Dr Xuan WANG (CNISM - University of Naples "Federico II"; CNR-SPIN, Napoli)

Slides Wang_Atmohead.pdf

7 GDAS/HYSPLIT models

Astroparticle experiments depend on a good knowledge of scattering and absorption of photons in the atmosphere. Typically two kinds of scattering can be distinguished, Mie scattering on large scale dust particles and Rayleigh scattering due to the molecular atmosphere. Both can be characterized quite well by measurements, but through advances in the modeling of the atmosphere in recent years, a very powerful alternative is provided. GDAS is a 3-hourly global model of the atmospheric state parameters on a 1 degree grid, based on real-time measurements and numeric weather prediction. HYSPLIT is a powerful tool to track the movement of air masses at various heights, and with it the aerosols. Typically the GDAS model is used in HYSPLIT to model the molecular atmosphere, and while the aerosol scattering itself can not be estimated using this tool, it is possible to track the path of air masses and make estimations of the clarity or the atmosphere depending on the origin of the aerosols (sea, desert, vegetation). Both GDAS and HYSPLIT were developed by the US weather department NOAA and the data are available through the internet without cost. In this talk we will present shortly the two models and some case studies for several astroparticle experiments.

Speaker: Martin Will (IFAE)

Slides Will_GDAS.pdf

Tuesday, 20 May

Overview of Experiments

Overview of the Atmospheric Calibration system for current and planned experiments

Convener: Dr Aurelio Siro Tonachini (TO)

8 Atmospheric Monitoring in the Pierre Auger Observatory

The Pierre Auger Observatory detects high-energy cosmic rays with energies above some 10^17 eV. It is built as a multi-hybrid detector measuring extensive air shower with different techniques. For the reconstruction of extensive air showers, the atmospheric conditions at the site of the observatory have to be known quite well. This is particularly true for reconstructions based on data obtained by the fluorescence technique. For these data, not only the weather conditions near ground are relevant, most important are altitude-dependent atmospheric profiles. Thus, the Pierre Auger Observatory has set up a dedicated atmospheric monitoring programme at the site of the observatory in the province Mendoza, Argentina. Most atmospheric monitoring activities aim primarily for a high-quality reconstruction of air showers. Further interests are beyond the scope of cosmic ray investigations, in the field of atmospheric science. Local measurements can be used for determining the accuracy of global model data at the site of the Observatory or can serve for dedicated studies of local conditions in the Pampa Amarilla, Argentina.

Speaker: Dr Bianca Keilhauer (Karlsruhe Institute of Technology KIT)

Slides Auger_AtmMonitoring_BKeilhauer_Padova2014_v2.pdf

9 Atmospheric monitoring in H.E.S.S.

Instruments applying the IACT method, such as H.E.S.S. (High Energy Stereoscopic System), observe VHE (very high energy, E>100GeV) photons indirectly, using the Earth's atmosphere as a calorimeter. In the H.E.S.S. data reconstruction, the properties of this component are estimated by Monte Carlo simulations of a yearly averaged atmosphere density profile. Deviations of the real atmospheric conditions from this assumed atmospheric model will result in a biased reconstruction of the primary gamma-ray energy and thus the resulting source spectrum. In order to keep the corresponding systematic effects to a minimum, H.E.S.S. operates a set of atmosphering monitoring devices that allows it to characterise the atmospheric conditions during data taking. This information in turn is then used in data selection. Here, a short overview with respect to their usage during source observation and a posteriori analysis data selection will be presented.

Speaker: Dr Joachim Hahn (MPIK)

Slides AtmoMonitoringTalkJoachim_final.pdf

10 Atmospheric Monitoring in MAGIC and Data Corrections

A method for analyzing returns of the custom-made 'micro'-LIDAR system, which is operated along side with the two MAGIC telescopes is presented. This method allows to calculate the transmission through the atmosperic boundary layer as well as thin cloud layers by applying exponential fits to regions in the signal that are dominated by Rayleigh scattering. Writing this real time transmission information into the data stream allows to apply atmospheric corrections in the MAGIC data analysis chain later on. Such corrections make it possible to extend the effective observation time of MAGIC under adverse atmospheric conditions and reduce the systematic errors of energy and flux in the data analysis. Further more it is possible to perform long-term studies of the observational conditions based on the LIDAR data.

Speaker: Mr Christian Fruck (MPI Munich)

Slides 2014_Padova_ATMOHEAD_LIDAR.pdf

11 FACT - Measuring atmospheric condition with an Imaging Air Cherenkov Telescope

For Imaging Air Cherenkov Telescopes, knowledge about the condition of the atmosphere is very important. Usually, this information is gathered by external devices like lidars and pyrometers. While pyrometers only give integral information, lidars have the problem that their lasers can affect data-taking. Based on experience from the First G-APD Cherenkov Telescope (FACT), we present possibilities to extract information about quality of the atmosphere as well as ambient light conditons directly with the Cherenkov telescope itself during data-taking.

Speaker: Ms Dorothee Hildebrand (ETH Zurich)

Slides fact_atmo_V2.pdf

11:00 Coffee Break

12 Atmospheric monitoring at the TNG site

For more than 20 years the TNG and its surroundings at the ORM have been the site for monitoring the atmosphere under several of its parameters. From the first instruments installed in the early '90s to characterize and show the quality of the sky at the chosen site (particularly the Automatic Weather Station and the DIMM) we evolved into the actual set up of remote sensing devices to be considered as a fundamental aid for the telescope, in particular for its safety and to optimize the scientific throughput. We will resume here the lessons learned, some results and the new choices for monitoring the atmosphere at the TNG.

Speaker: Mr Adriano Ghedina (TNG)

Slides Ghedina_Atmohead_TNG.pdf

13 Atmospheric Monitoring and Calibration for CTA

Speaker: Michele Doro (PD)

Slides doro_2014_atmohead_cta_v4.pdf

14 All sky camera, Lidar, and Electric Field Meter for the ASTRI SST-2M prototype for CTA

ASTRI, Astrofisica con Specchi a Tecnologia Replicante Italiana, is a flagship project of the Italian Ministry of Education, University and Research, entirely supported and led by the Italian National Institute of Astrophysics, INAF. The project is developed in the framework of the International Cherenkov Telescope Array, CTA. The primary goal of the ASTRI project is the realization of a wide field of view end-to-end prototype of a Small Size Telescope (SST-2M) for the CTA devoted to the investigation of the energy range from a few TeV up to hundreds of TeV. The ASTRI SST-2M end-to-end prototype, currently under construction, will be installed and operated in Italy at the INAF observing station located at Serra La Nave on Mount Etna during next autumn 2014. In the framework of the environmental monitoring studies, a set of auxiliary instrumentation has been configured on site and in particular an all-sky camera, an Electric Field Meter and a Raman Lidar. In this contribution we present our progress in detecting clouds in color all-sky images taken during the day and the night, the results in monitoring the volcanic ash with our Lidar system, and the first results coming from the Electric Field Meter, mainly acting as lightning detector.

Speaker: Dr Giuseppe Leto (INAF-Osservatorio Astrofisico di Catania)

Slides ASTRI_efmlidallsky_atmohead2014V2.pdf

13:00 Lunch Break

14:30 Visit to Palazzo Bo

Guided tour in English

Highlights

Convener: Dr Karim Louedec (LPSC, CNRS/IN2P3, UJF-INPG, Grenoble)

15 Raman LIDARs for Pierre Auger Observatory: field experiences and results.

The optical properties of the troposphere are quite important for ultra-high energy cosmic ray observatories that use the atmosphere as a giant calorimeter. To estimate the energy of a cosmic ray extensive air shower (EAS), the amount of UV scintillation light generated by an EAS (air fluorescence) can be measured, and, the optical transparency of the atmosphere affects the amount of UV light that reaches the ground-based air fluorescence detector. The most variable component of atmospheric optical transmission is the vertical aerosol optical depth (VAOD). The Raman LIDAR is the technique to be preferred for the measurements of the VAOD in the UV wavelength range [1]. We present the design and the technical details, and the performances and the limitations of the Raman LIDAR systems used at the Pierre Auger Observatory [2] and in the Auger R&D in South-Eastern Colorado [3]. The latter field experiment combined a UV backscattered Raman LIDAR and a side-scattering detector, i.e., a LIDAR detector in bi-static configuration; this was a model of the new setup of part of the atmospheric instrumentation [4], now in use at the Pierre Auger Observatory, and it was designed to improve the methods to measure the VAOD profiles. [1] G. Pappalardo, et al., Aerosol lidar intercomparison in the framework of the EARLINET project. 3. Raman LIDAR algorithm for aerosol extinction, backscatter, and LIDAR ratio, Appl. Optics 43 (2004) 5370{538. [2] Pierre Auger Collaboration, Iarlori M., Visconti G. (2012), Atmospheric monitoring with LIDARs at the Pierre Auger Observatory. THE EUROPEAN PHYSICAL JOURNAL PLUS, vol. 127, ISSN: 2190-5444, doi: 10.1140/epjp/i2012-12092-0 [3] Pierre Auger Collaboration et al., (2012), UV Raman lidar and side scattering detector for the monitoring of aerosol optical transmission at the Pierre Auger Observatory, PROCEEDINGS FOR THE ILRC 2012, Greece, June 2012. [4] Pierre Auger Collaboration (2013), Techniques for measuring aerosol attenuation using the Central Laser Facility at the Pierre Auger Observatory, JOURNAL OF INSTRUMENTATION, 8, P04009, 10.1088/1748-0221/8/04/P04009, 1748-0221, 2013.

Speaker: Dr Vincenzo Rizi (CETEMPS-DSFC and INFN, Università Degli Studi dell'Aquila)

Slides Rizi_Atmohead_drama.pptx Rizi_Atmohead.pptx

16 Monte Carlo simulations of atmospheric showers in the future

Last year, the air shower simulation model CORSIKA had a major release opening new windows in term of uncertainty due to hadronic interaction models and of simulation time. On the one hand, the two hadronic models EPOS and QGSJETII were updated taking into account new LHC data. As a consequence the uncertainties in air shower observables were reduced by about a factor of 2 at the highest energies. On the second hand, two new possibilites of running CORSIKA was introduce: either in a parallel mode on big CPU clusters allowing the simulation of unthinned showers in a reasonable time, or using cascade equations to reduce the simulation time by about of factor of 10 on a single CPU. All these improvements togehter with future developments will be presented.

Speaker: Dr Tanguy Pierog (KIT, IKP)

Slides CORSIKA_Pierog.pdf

16:30 Coffe Break

Overview of Experiments

Overview of the Atmospheric Calibration system for current and planned experiments

Convener: Dr Karim Louedec (LPSC, CNRS/IN2P3, UJF-INPG, Grenoble)

17 The Atmospheric Monitoring System of the JEM-EUSO Space Mission

An Atmospheric Monitoring System (AMS) is a mandatory and key device of a space-based mission which aims to detect Ultra-High Energy Cosmic Rays (UHECR) and Extremely-High Energy Cosmic Rays (EHECR) from Space. JEM-EUSO has a dedicated atmospheric monitoring system that plays a fundamental role in our understanding of the atmospheric conditions in the Field of View (FoV) of the telescope. Our AMS consists of a very challenging space infrared camera and a LIDAR device, that are being fully designed with space qualification to fullfil the scientific requirements of this space mission. This AMS will provide information of the cloud cover in the FoV of JEM-EUSO, as well as measurements of the cloud top altitudes with an accuracy of 500 m and the optical depth profile of the atmosphere transmittance in the direction of each air shower with an accuracy of 0.15 degree and a resolution of 500 m. This will ensure that the energy of the primary UHECR and the depth of maximum development of the EAS ( Extensive Air Shower) are measured with an accuracy better than 30% primary energy and 120 g/cm2 depth of maximum development for EAS occurring either in clear sky or with the EAS depth of maximum development above optically thick cloud layers. Moreover a stereoscopic retrieval technique and a very novel that seems to be the most promising radiometric retrieval technique considering the LIDAR shots as calibration points are under development to infer the Cloud Top Height (CTH) of all kind of clouds, thick and thin clouds in the FoV of the JEM-EUSO space telescope.

Speaker: Prof. Maria Rodriguez Frias (Space and Astroparticle Group. UAH Madrid)

Slides Rodriguez_JEM-EUSO-MDRF-AtmoHEAD2014.pdf

Instruments and Tecniques Developments

Convener: Dr Karim Louedec (LPSC, CNRS/IN2P3, UJF-INPG, Grenoble)

18 Thick & Thin Cloud Top Height Retrieval Algorithm with the Infrared Camera & LIDAR of the JEM-EUSO Space Mission.

JEM-EUSO is a space-based telescope which will detect Ultra High Energy Cosmic Rays (UHECR) and Extremely High Energy Cosmic Rays (EHECR) using the atmosphere as a calorimeter. It will be located at the International Space Station (ISS), and will look down to the atmosphere. To estimate the energy and arrival direction of the UHECR & EHECR as well as its primary composition, the UV light profile from EAS is needed to be measured. The observed profile depends on atmospheric conditions such as the clouds top height. Unlike stationary observatories on the ground, the JEM-EUSO space telescope traverses above various atmospheric situations within its large observation area. To characterize the properties of the atmosphere, the JEM-EUSO space mission comprises an Atmospheric Monitoring System (AMS) with an infrared camera and a LIDAR. As the scientific requirement of this project is to retrieve the clouds height and not the brightness temperature of the clouds it is mandatory to develop an effective radiative retrieval algorith that retrieves directly the height of the cloud avoiding any indirect approach that do not retrieve the cloud height and therefore increasing the contribution to the NETD Budget of the Infrared camera. Therefore, a novel radiative retrieval algorith that seems to be the most promising to achieve the Infrared camera scientific requirement, i.e., to retrieve directly the cloud top height is presently under development, taking into account the LIDAR shots as calibration points in the FoV of the infrared camera image.

Speaker: Ms Guadalupe Saez Cano (Space and Astroparticle Group, UAH, Madrid)

Slides SaezCano_Atmohead.pdf

19 Clouds phase identification based on brightness temperatures provided by the bi-spectral IR Camera of JEM-EUSO Mission

Cloud information is extremely important to correctly interpret the JEM-EUSO telescope data since UV radiation coming from the Extensive Air Shower can be partially absorbed or reflected by clouds. In order to observe the atmosphere and clouds in the field of view of the UV telescope the JEM-EUSO system will include an atmospheric monitoring system, which consist of a LIDAR and an IR Camera. Different methods can be applied to retrieve the cloud top height from IR images: stereovision and techniques based on radiative measurements. Until now several radiative algorithms have been developed to retrieve the cloud top temperature from the brightness temperatures (BT) that the IR Camera will provide in two IR spectral bands (10.8 and 12 m). In some cases the performance of the algorithms depends on cloud phase: water, ice or mixed. For this reason the identification of the cloud phase is valuable information for the correct interpretation of the cloud temperatures retrieved by radiative algorithms. Cloud classification from bands in the 10-12 (micrometers) spectral region is not an easy task. Some previous proposals based on BT and brightness temperature difference (BTD) in 11 and 12 (micrometers) bands have revealed that there are not clear limits to determine unambiguously the phase. In this work we present criteria for BTD and BT(10.8m) to retrieve the cloud phase. These criteria has been checked with MODIS images to evaluate the possibilities to identify cloud phase with the JEM-EUSO IR Camera, although these results can be also applied to other sensors measuring in the same spectral bands.

Speaker: Dr Pacheco Briz (Universidad Carlos III de Madrid)

Slides Briz_Atmohead_1.pptx

20 The EUSO-TurLab project

The TurLab facility is a laboratory, equipped with a rotating tank, located at the Physics Department of the University of Torino. It consists of a 5 m diameter tank, which is used for fluido-dynamics studies. The system has been thought mainly for studying problems where system rotation plays a key role in the fluid behaviour, for example in atmospheric and oceanic flows at different scales. The tank can be filled with different fluids of variable density allowing studies in stratified conditions too; sea waves (infinite fetch) can be reproduced and analysed. The tank can be also used to simulate parts of the terrestrial surface with optical characteristics of different environments (snow, grass, ocean, land,..... fogs and clouds can be simulated as well). The tank is located in an extremely dark place, therefore the light intensity can be controlled artificially. The EUSO-TurLab project is an on-going activity to reproduce artificially atmospheric and luminous situations that JEM-EUSO will encounter on its orbits around the Earth. This is suitable to test the detector performance as well as the trigger system. In this talk, a review of the on-going tests related to the JEM-EUSO mission will be presented.

Speaker: Dr Mario Edoardo Bertaina (TO)

Slides Bertaina_Atmohead.pdf

20:15 Social Dinner at Trattoria 7 Vizi

http://www.trattoriasettevizi.com/

Wednesday, 21 May

Companies

Convener: Raquel de los Reyes (MPIK)

21 LICEL

Speaker: Bernd Mielke (LICEL GmbH)

Slides Licel_Padova2014.pdf

22 CAEN

Speaker: Mr Giuliano Mini (CAEN SpA)

Slides Mini_Atmohead2014_CAEN.pdf

23 Raymetrics

Speaker: George Avdikos (Raymetrics)

Slides Advikos_Atmohead_Raymetrics.ppt

24 Bright Solutions

Speaker: Luca Carra' (Bright Solutions)

Slides Carra_Atmohead_Bright_Solutions.pdf

Instruments and Tecniques Developments

Convener: Raquel de los Reyes (MPIK)

25 ARCADE : description of the project and setup of the LIDAR/AMT system

The Atmospheric Research for Climate and Astroparticle DEtection (ARCADE) project is a 3 years project funded by MIUR, that aims to study the aerosol attenuation of UV light in atmosphere using multiple instruments and techniques, as those commonly used in the cosmic rays community: elastic Lidar, Raman Lidar, side-scattering measurements using a distant laser source. All measurements will be acquired on the same air mass at the same time, in semi-desertic site near Lamar, Colorado. For each instrument, multiple analysis techniques will be tested: the target is a better comprehension of the systematics and limits of applicability of each method. The system is composed by a Lidar (elastic+Raman), fully designed and built within this project, and by the Atmospheric Monitoring Telescope (AMT), a telescope for the detection of UV light owned by the Colorado School of Mines. The setup of the two instruments is described in detail here. The project is presently entering its third year : the Lidar system has been tested at the University of L'Aquila last February before shipment to the U.S., and the AMT has been recently reinstalled and tested in Lamar. During the next month the ARCADE group will work out the final setup of the Lidar+AMT system in Lamar and begin data acquisition.

Speaker: Laura Valore (NA)

Slides ValoreL_AtmoHEAD2014.pdf

26 Retrieval of optically thin cloud emissivity from brightness temperatures provided by IR Camera of JEM-EUSO Mission

Clouds interact with the radiation propagating through the atmosphere absorbing, reflecting and transmitting part of the energy. This interaction may lead to misinterpretation of data retrieved from the radiation observed by JEM-EUSO UV telescope. At the same time the interaction cloud-ratiation can be used to retrieve cloud properties. JEM-EUSO Mission includes an Atmospheric Monitoring System (AMS), consisting of a LIDAR and an IR Camera, devoted to provide the cloud coverage and the cloud height in the FOV of the main UV Telescope. Different methods can be applied to retrieve the cloud top height from IR images: stereoscopic and radiative techniques. Radiative algorithms are based on the Radiative Transfer Equation which changes significantly depending on the cloud optical depth (thick or thin clouds). The cloud temperature retrieval becomes much more difficult for thin clouds (emissivity lower than 1). In this work we present a methodology based on brightness temperatures in 10.8 and 12 micrometers bands measured by the JEM-EUSO IR camera. The method uses Look Up Tables (LUTs) which involve values of emissivity and brightness temperature differences in both bands. This LUT method has been validated with data obtained by simulation but also in real scenarios (MODIS images). The results are very promising for emissivities higher than 0.5. For lower emissivities, the retrievals become much more difficult since the IR radiation impinging the IR Camera also comes from other emitters such as Earth surface and atmosphere beneath the cloud.

Speaker: Dr Pacheco Briz (Universidad Carlos III de Madrid)

Slides Briz_Atmohead_LUT.pptx

11:05 Coffee Break

27 Recent development of the H.E.S.S. Lidar

We present recent results obtained with the H.E.S.S. Lidar installed and operating for the last four years at the Namibian desert. Results obtained, using a recent Klett type analysis, permit a better correlation with relevant H.E.S.S. type related run parameters. Future plans as scenarios to implement these results on the main physics analysis chain will also be discussed.

Speaker: Dr George Vasileiadis (LUPM)

Slides lidarcm.pdf

28 Atmospheric Monitoring With An Infrared Radiometer

The molecular atmosphere has a number of windows where it is effectively transparent to electromagnetic radiation, one of these being in the infrared 8-14 micron region. The presence of clouds and aerosols, which are more effective emitters of infrared radiation, in the atmosphere show up as an increase in the effective brightness temperature compared to the clear sky. This talk will cover the results from operating a scanning radiometer at the H.E.S.S. site in Namibia in determining atmospheric conditions.

Speaker: Dr Michael Daniel (University of Liverpool)

Slides Radiometer.pdf

29 FRAM for CTA

The Cherenkov Telescope Array (CTA) is a project to build a new generation ground-based gamma-ray observatory. Among other goals, the project aims to achieve high precision measurements of gamma-ray properties while maximizing the use of observation time. These objectives require detailed and fast information about atmospheric conditions, particularly the transparency (varying mostly with aerosol content) and cloud cover (including thin high-altitude clouds). This knowledge is required not only to select and calibrate data after observation, but also to make on-the-fly scheduling decisions. To provide such data without interfering with the observation (as would be the case when using laser-based methods), we propose to use the FRAM (F(/Ph)otometric Robotic Atmospheric Monitor) device, which is a small robotic astronomical telescope with a large field of view and a sensitive CCD camera. FRAM will use stellar photometry to measure atmospheric extinction across the field of view of the CTA. The fast robotic mount of the telescope allows quick observation of multiple fields, when the array is split, and even a check of the conditions in the directions of upcoming observations. The FRAM concept is built upon an experience gained with a similar device operated at the Pierre Auger Observatory.

Speaker: Dr Petr Janecek (Institute of Physics AS CR)

Slides janecek_fram_cta.pdf

30 All Sky Camera for the CTA CCF Atmospheric Calibration work package

The All-Sky-Camera (ASC) is a passive non-invasive imaging system for rapid night sky atmosphere monitoring. The operation of the ASC will hence not disturb standard operation of the CTA telescopes, however results from the measurements will help to improve the accuracy and effective duty-cycle of the CTA observatory. The goal of ASC, and recently developed intelligent image analysis algorithms, is to identify the position of clouds, atmospheric attenuation and time evolution of the local sky conditions. The monitoring will be able to predict the night-sky quality on a short term basis. In case of partly cloudy night-sky, the cameras will identify uncovered regions of the sky during the CTA operation time, and pinpoint those regions where observation targets can be viewed without atmospheric disturbance.

Speaker: Mr Dusan Mandat (Institute of Physics Academy of Sciences of the Czech Republic)

Slides All_Sky_Camera_for_CTA_Mandat.pdf

13:00 Lunch Break

31 Weather and atmosphere observation with the ATOM all-sky camera

The Automated Telescope for Optical Monitoring for H.E.S.S. (ATOM) is an optical 75cm telescope which operates fully automated. As there is no observer present during observation, an auxiliary all-sky camera serves as weather monitoring system. This device takes an 180° image of the whole sky every three minutes. The gathered data then undergoes live-analysis by performing astrometric comparison with a theoretical night sky model, interpreting the absence of stars as cloud coverage. It also serves as tool for a meteorological analysis of the observation site of the the upcoming Cherenkov Telescope Array (CTA). This presentation covers design and benefits of the all-sky camera and additionally gives an introduction into current efforts to integrate the device into the atmosphere analysis programme of H.E.S.S.

Speaker: Mr Felix Jankowsky (LSW)

Slides Jankowski_Atmohead_ATOM_ASC.pdf

32 Remote sensing of clouds with Cherenkov telescopes

Remote sensing of atmosphere is conventionally done via a study of extinction/scattering of light from natural (Sun, Moon) or artificial (laser) sources. Cherenkov emission from extensive air showers generated by cosmic rays provides one more natural light source distributed throughout the atmosphere. We show that Cherenkov light carries information on three-dimensional distribution of clouds and aerosols in the atmosphere and on the size distribution and scattering phase function of cloud/aerosol particles. Therefore, it could be used for the atmospheric sounding. The new atmospheric sounding method could be implemented via an adjustment of technique of imaging Cherenkov telescopes. The atmospheric sounding data collected in this way could be used both for atmospheric science and for the improvement of the quality of astronomical gamma-ray observations.

Speaker: Dr Denys Malyshev (ISDC)

Slides Malyshev_Atmohead.pdf

33 The impact of clouds on image parameters in IACT at very high energies

The effective observation time with the Cherenkov telescopes arrays is limited to clear sky conditions due to considerable absorption of Cherenkov light by the possible presence of clouds. However below the cloud altitude the primary particles with high energies can still produce enough Cherenkov photons to allow detection by the large telescopes. In this paper, using the standard CORSIKA code, we investigate the changes of shower image parameters due to cloud absorption for gamma-ray and proton showers with various energies - from 2 TeV to 100 TeV and from 10 TeV to 200 TeV, respectively. We consider the clouds with different transmissions located at various altitudes above the ground level (between 8 km and 3 km). We show that, for both simulated primary particles at fixed energy, in the presence of clouds the WIDTH and the DIST distributions are shifted towards larger values. This shift decreases with the cloud altitude. The LENGTH distributions are shifted towards smaller values for the primary gamma-ray, while for primary proton this shift is not expected. We conclude that large Cherenkov telescopes with large camera FOV might be used for observation of energetic gamma-ray shower.

Speaker: Dr Dorota Sobczynska (University of Lodz)

Slides Sobczynska_atmohead.pdf

34 Remote Sensing of Clouds using Satellites, Lidars, CLF and IR Cameras at the Pierre Auger Observatory

Speaker: Dr Johana Chirinos (MTU)

Slides Chirinos_Atmohead.ppt

16:30 Coffee Break and Goodbye