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Three volcanic plumes were detected during the Tajogaite volcano eruptive activity (Canary Islands, Spain, September–December 2021) over the Iberian Peninsula. The spatiotemporal evolution of these events is characterised by combining passive satellite remote sensing and ground-based lidar and sun-photometer systems. The inversion algorithm GRASP is used with a suite of ground-based remote sensing instruments such as lidar/ceilometer and sun-photometer from eight sites at different locations throughout the Iberian Peninsula. Satellite observations showed that the volcanic ash plumes remained nearby the Canary Islands covering a mean area of 120 ± 202 km2 during the whole period of eruptive activity and that sulphur dioxide plumes reached the Iberian Peninsula. Remote sensing observations showed that the three events were mainly composed of sulphates, which were transported from the volcano into the free troposphere. The high backscatter-related Ångström exponents for wavelengths 532–1064 nm (1.17 ± 0.20 to 1.40 ± 0.24) and low particle depolarization ratios (0.08 ± 0.02 to 0.09 ± 0.02), measured by the multi-wavelength Raman lidar, hinted at the presence of spherical small particles. The layer aerosol optical depth at 532 nm (AODL532) obtained from lidar measurements contributed between 49% and 82% to the AERONET total column AOD at 532 nm in event II (11–13 October). According to the GRASP retrievals, the layer aerosol optical depth at 440 nm (AODL440) was higher in all sites during event II with values between 0.097 (Badajoz) and 0.233 (Guadiana-UGR) and lower in event III (19–21 October) varying between 0.003 (Granada) and 0.026 (Évora). Compared with the GRASP retrievals of total column AOD at 440 nm, the AODL440 had contributions between 21% and 52% during event II. In the event I (25–28 September), the mean volume concentrations (VC) varied between 5 ± 4 µm3cm-3 (El-Arenosillo/Huelva) and 17 ± 10 µm3cm-3 (Guadiana-UGR), while in event II this variation was fro, Évora team funded by national funds through FCT - Fundação para a Ciência e Tecnologia, I.P., in the framework of the ICT project with the references UIDB/04683/2020 and UIDP/04683/2020 and by TOMAQAPA (PTDC/CTAMET/29678/2017). The authors acknowledge the GRASP-ACE (Grant agreement ID: 778349), ACTRIS-IMP (Grant agreement ID:871115), ATMO-ACCESS (Grant Agreement ID: 101008004), PROBE (COST Action number: CA18235), HARMONIA (COST Action number: CA21119), EUMETNET through the E-PROFILE program and REALISTIC (Grant agreement ID:101086690) projects. The authors acknowledge the support through ACTRIS-2 under grant agreement no.654109. This work was partially supported by the Spanish national projects PID2019-103886RB-I00/AEI/10.13039/501100011033, INTEGRATYON3 (PID2020-117825GB-C21 and PID2020-117825GB-C22), ELPIS (PID2020-120015RB-I00), CLARIN (CGL2016-81092-R), ePOLAAR (RTI2018-097864-B-I00), CAMELIA (PID2019-104205GB-C21/AEI/10.13039/501100011033) and ACTRIS-España (CGL2017-90884REDT), by University of Granada Plan Propio through Singular Laboratory (LS2022-1) program, by the Andalusia Autonomous Government projects AEROPRE (P18-RT-3820) and ADAPNE (P20_00136), by the UGR-FEDER projects DEM3TRIOS (A-RNM-430-UGR20) and MOGATRACO (A-RNM-524-UGR20) and partially by the Scientific Units of Excellence Program (grant no. UCE-PP2017-02), and by the R+D+i grant RTI 2018-097332-B-C22 funded by MCIN/AEI/ 10.13039/501100011033/ and “ERDF A Way of Doing Europe”. M.-Á. López-Cayuela and C.V. Carvajal-Pérez are supported by the INTA predoctoral contract program., Peer Reviewed, Postprint (published version)

The depth of the aerosol layer at the Villum Research Station at Station Nord in the high Arctic is analysed based on 8 years of observations from a ceilometer and one full year from a wind lidar. The layer is of particular interest for aerosol process modelling and atmospheric chemistry studies. The depth of the aerosol layer is assigned to the inflection point in the attenuated backscatter profile by two methods; one is based on polynomial approximation of the profile and the other is direct numerical differentiation. The analysis is based on two types of hourly profiles; one consists of averaging the attenuated backscatter observations and the other by computing the median. Due to sporadic occurrence of outliers in the ranges around 50 m in the ceilometer observations, this part of the profile is not used in this study. Restricting the observations to heights above 100 m, the depths of the aerosol layer are found to be typically ≈230 m. It varies little between winter and summer, but the spread in the depth is larger during the winter as compared to summer. To extend the study of the aerosol-layer depth below 100 m, a method is applied that combines the ceilometer measurements with the carrier-to-noise ratio from the wind lidar. The results are available for 2018 only, and they show aerosol-layer depths below ≈80 m as well as depths around 230 m and they show few observations between ≈80 and ≈230 m. Near the ground, the observed backscatter exhibits a pronounced seasonal variation, having low values during the summer and high values during the winter. The strength of the seasonal variability decreases with height, especially above the aerosol-layer depth, and is virtually absent at 1 km.

This study presents a synergistic approach to the study of the aerosol optical and microphysical properties measured in La Palma, Spain, during the 2021 eruption of the Cumbre Vieja volcano (from 19 September to 13 December 2021). This study aims to characterize the different phases of the volcanic eruption using the spatio-temporal evolution of the event together with the mass concentration quantification of four different atmospheric layers. The impact of the plume’s pathway that reached the South of France is analyzed. Here, passive and active remote sensors were used, namely CL51 and CL61 ceilometers and AERONET sunphotometers. The attenuated backscattering ranged from 0.8 to 9.1 × 10-6 (msr)-1 and the volume depolarization ratio measured nearby the volcano was up to 0.3. The ash plume remained within the first 4 km agl, with intense episodes that reached mean aerosol optical depth values of up to 0.4. Thirteen study cases were selected where coarse mode was dominant over fine mode. For the data selection, the fine and coarse lidar ratios found were 3.9 ± 0.8 and 21.0 ± 3.8 sr in the north and 6.9 ± 1.8 and 30.1 ± 10.3 sr in the south. The ash mass concentration reached moderate levels with maximum values of up to 313.7 µ gm., This work was financially supported by ONERA within the framework of the PROMETE project 2017–2021; the Spanish Ministry of Science and Innovation (PID2019-103886RB-I00nAEI n10.13039n501100011033); and the H2020 program from the European Union (GA no. 654109, 778349, 871115, 101008004 and 101086690)., Peer Reviewed, Postprint (published version)

In this study, about two years of data from Östergarnsholm in the Baltic Sea are used to analyse offshore low-level clouds (LLCs) influenced by low-level jets (LLJs) in the marine atmospheric boundary layer. The LLJs are passages of strong horizontal winds near the surface and are measured using a Doppler LiDAR, which provides information about the wind speed and wind direction up to 300 meters. In this study we define two groups of LLJs depending on the height at which they occur; 1) LLJs with maximum wind speed at heights below 300 meters that are clearly identified from the LiDAR data, and 2) LLJs that occur at heights around 300 meters or higher and are not clearly captured by the LiDAR but are assumed by visual inspection. The clouds are quantified using a ceilometer which provides information about the cloud base heights (CBH). The main objectives of this study were to identify periods of coincident LLJs and LLCs, to classify these identified LLJs and LLCs and to provide general statistics of their interaction. The combination of LLJ- and LLC presence, and the interaction between these, are new research. The analysis showed that the highest LLJ frequency regarding all LLJs was 47.7 %, with a maximum speed of 17.5 ms^-1 and occurred during winter. Only 4.38 % of these LLJs occurred below 300 m. The largest share of all LLJs below 300 m occurred during summer (75.6 %), where the mean maximum speed was 11.1 ms^-1. Largest LLC presence during active LLJs occurred during the winter (56.0 % regarding all LLJs, 64.5 % regarding LLJs below 300 m). The possible LLJ influence on the formation of LLCs was large during late autumn, winter, and early spring since the LLJ mean height and the $CBH$ were at approximately the same height. It was also found that the LLJs induced an increased turbulence intensity below and above the LLJs cores. The increased mixing above the jet core could lead to turbulent transport of cold and humid air, leading to LLC formation. The results o, Vindar och moln har stor betydelse för jorden. Vindar är viktiga genom deras påverkan på dagens och framtida väder (och indirekt på prognoser), eftersom de kan transportera varm eller kall luft, fuktig eller torr luft, mellan olika områden och därmed bidra till att väderförhållandena rubbas så fort vindriktningen ändras. Moln är viktiga genom deras påverkan på jordens strålningsbalans. Således är molnen en av nycklarna till att jordens globala medeltemperatur ser ut som den gör. Ergo är det viktigt, speciellt för meteorologer, att känna till de fysikaliska processerna som är inblandade i vindars och molns formning för att vässa väderprognoser och globala klimatförutsägelser. Genom att presentera en specifik karaktärisering av Östersjöns meteorologi, med fokus på low-level jets (LLJs, vindar upp till omkring 300 meter) och low-level clouds (LLCs, moln upp till 2000 meter) över Östergarnsholm observatorium strax öster om Gotland, utrustar den här studien en bas för vidare avancemang i förståelsen av samspelet mellan LLJs och LLCs och chansen ökar att förbättra prognoser gällande väder och klimat. LLJs är korridorer av snabbt färdande vind som kännetecknas av en maxhastighet på en viss lägre höjd. Över Östersjön inträffar de på grund av olika sorters kontraster mellan land och hav. Detta är framför allt kontraster i friktion och temperatur, där den lägre friktionen över havet medför starkare vindar och tvärtom över land. Starkare vindar är mycket gynnsamt för vindkraften till havs eftersom de kan förse vindkraftverken med mer kraft vilket är en fördel för mer effektiv vindkraft. I samma veva som vindarna bidrar till en effektivare vindkraft, så förkortar LLJs livslängden på vindkraftverken. Relevant för den här studien är också LLJs förmåga att modifiera termodynamiken i den omgivande luften. Detta görs genom att LLJs skickligt transporterar värme, fukt och aerosoler till högre höjder. Detta kan småningom leda till att LLCs bildas och utvecklas, eftersom moln kräver va

In this study, about two years of data from Östergarnsholm in the Baltic Sea are used to analyse offshore low-level clouds (LLCs) influenced by low-level jets (LLJs) in the marine atmospheric boundary layer. The LLJs are passages of strong horizontal winds near the surface and are measured using a Doppler LiDAR, which provides information about the wind speed and wind direction up to 300 meters. In this study we define two groups of LLJs depending on the height at which they occur; 1) LLJs with maximum wind speed at heights below 300 meters that are clearly identified from the LiDAR data, and 2) LLJs that occur at heights around 300 meters or higher and are not clearly captured by the LiDAR but are assumed by visual inspection. The clouds are quantified using a ceilometer which provides information about the cloud base heights (CBH). The main objectives of this study were to identify periods of coincident LLJs and LLCs, to classify these identified LLJs and LLCs and to provide general statistics of their interaction. The combination of LLJ- and LLC presence, and the interaction between these, are new research. The analysis showed that the highest LLJ frequency regarding all LLJs was 47.7 %, with a maximum speed of 17.5 ms^-1 and occurred during winter. Only 4.38 % of these LLJs occurred below 300 m. The largest share of all LLJs below 300 m occurred during summer (75.6 %), where the mean maximum speed was 11.1 ms^-1. Largest LLC presence during active LLJs occurred during the winter (56.0 % regarding all LLJs, 64.5 % regarding LLJs below 300 m). The possible LLJ influence on the formation of LLCs was large during late autumn, winter, and early spring since the LLJ mean height and the $CBH$ were at approximately the same height. It was also found that the LLJs induced an increased turbulence intensity below and above the LLJs cores. The increased mixing above the jet core could lead to turbulent transport of cold and humid air, leading to LLC formation. The results o, Vindar och moln har stor betydelse för jorden. Vindar är viktiga genom deras påverkan på dagens och framtida väder (och indirekt på prognoser), eftersom de kan transportera varm eller kall luft, fuktig eller torr luft, mellan olika områden och därmed bidra till att väderförhållandena rubbas så fort vindriktningen ändras. Moln är viktiga genom deras påverkan på jordens strålningsbalans. Således är molnen en av nycklarna till att jordens globala medeltemperatur ser ut som den gör. Ergo är det viktigt, speciellt för meteorologer, att känna till de fysikaliska processerna som är inblandade i vindars och molns formning för att vässa väderprognoser och globala klimatförutsägelser. Genom att presentera en specifik karaktärisering av Östersjöns meteorologi, med fokus på low-level jets (LLJs, vindar upp till omkring 300 meter) och low-level clouds (LLCs, moln upp till 2000 meter) över Östergarnsholm observatorium strax öster om Gotland, utrustar den här studien en bas för vidare avancemang i förståelsen av samspelet mellan LLJs och LLCs och chansen ökar att förbättra prognoser gällande väder och klimat. LLJs är korridorer av snabbt färdande vind som kännetecknas av en maxhastighet på en viss lägre höjd. Över Östersjön inträffar de på grund av olika sorters kontraster mellan land och hav. Detta är framför allt kontraster i friktion och temperatur, där den lägre friktionen över havet medför starkare vindar och tvärtom över land. Starkare vindar är mycket gynnsamt för vindkraften till havs eftersom de kan förse vindkraftverken med mer kraft vilket är en fördel för mer effektiv vindkraft. I samma veva som vindarna bidrar till en effektivare vindkraft, så förkortar LLJs livslängden på vindkraftverken. Relevant för den här studien är också LLJs förmåga att modifiera termodynamiken i den omgivande luften. Detta görs genom att LLJs skickligt transporterar värme, fukt och aerosoler till högre höjder. Detta kan småningom leda till att LLCs bildas och utvecklas, eftersom moln kräver va

We present results from an analyses of cloud cover based on profiles of the attenuated backscatter coefficient from an 8‐year long data series (July 2011 – April 2019). The observations are carried out in the high Arctic by a ceilometer with a maximum range setting of 7.7 km from the Villum Research Station at Station Nord, Greenland. Results show that the hourly cloud cover turned out to follow a U‐shaped rather than Gaussian‐like distribution. Annual and seasonal cloud cover variation is illustrated. The cloud cover is larger during the autumn and winter as compared to summer and spring. The cloud cover exhibits a substantial variation from year to year without a clear trend. The cloud cover during spring is low and decreasing between 2012 and 2017. The cloud cover during the autumn of 2016 is lowest compared to the other years. The observed cloud cover is compared to the cloud cover provided in the ERA5 reanalysis data‐set. The cloud cover for low clouds and medium clouds are combined to represent a total height of 6 km. Both the observed and modelled cloud cover is larger during winter as compared to summer‐time cloud cover. The measured reduction in the cloud cover for the autumn of 2016 is present in the reanalysis data as well but the measured low cloud cover during spring is not apparent in the reanalysis data. Because the cloud cover distribution is U‐shaped rather than of a Gaussian nature, standard metrics are not applicable. We apply a generalized skill score that is developed for contingency tables or joint histograms. Three skill scores were calculated. It was found that for all three methods, skills for the predictability of the cloud cover by the ERA5 modelling is better for winter than summer and is poor during the spring.

Continuous measurements of blowing snow are scarce, both in time and space. Satellites now provide the opportunity to derive blowing snow occurrences, transport and sublimation rates over Antarctica. These products are extremely valuable and offer a continental-wide assessment of blowing snow, which is an important but unknown component of the surface mass balance of the Antarctic ice sheet. However, little ground truth is available to validate these retrievals. The recent application of ceilometers for detection of blowing snow frequencies provides an opportunity to validate the satellite retrievals of blowing snow. A routine to detect blowing snow occurrence from ground-based remote sensing ceilometers has been developed at two coastal locations in East Antarctica for the 2011–2016 time period. Thanks to their ground-based location, ceilometers are able to detect blowing snow events in the presence of clouds and precipitation, which can be missed by the satellite, since optically thick clouds impede the penetration of the signal. In coastal areas, more than 90% of blowing snow occurs under cloudy conditions and represent 30 to 56% of all cloudy conditions at Princess Elisabeth and Neumayer III (Neumayer hereafter) stations, respectively. For cloud-free conditions, 8% of the measurements at Princess Elisabeth (and none at Neumayer) are identified as blowing snow by the satellite but not by the ceilometer, likely due to differences in sensors, limitation of the surface identification by the satellite, or the spatial inhomogeneity of the blowing snow event. While the satellite blowing snow retrieval is a useful product, further investigation is needed to reduce the uncertainties on blowing snow frequencies associated with clouds., Mathematical Geodesy and Positioning

Continuous measurements of blowing snow are scarce, both in time and space. Satellites now provide the opportunity to derive blowing snow occurrences, transport and sublimation rates over Antarctica. These products are extremely valuable and offer a continental-wide assessment of blowing snow, which is an important but unknown component of the surface mass balance of the Antarctic ice sheet. However, little ground truth is available to validate these retrievals. The recent application of ceilometers for detection of blowing snow frequencies provides an opportunity to validate the satellite retrievals of blowing snow. A routine to detect blowing snow occurrence from ground-based remote sensing ceilometers has been developed at two coastal locations in East Antarctica for the 2011–2016 time period. Thanks to their ground-based location, ceilometers are able to detect blowing snow events in the presence of clouds and precipitation, which can be missed by the satellite, since optically thick clouds impede the penetration of the signal. In coastal areas, more than 90% of blowing snow occurs under cloudy conditions and represent 30 to 56% of all cloudy conditions at Princess Elisabeth and Neumayer III (Neumayer hereafter) stations, respectively. For cloud-free conditions, 8% of the measurements at Princess Elisabeth (and none at Neumayer) are identified as blowing snow by the satellite but not by the ceilometer, likely due to differences in sensors, limitation of the surface identification by the satellite, or the spatial inhomogeneity of the blowing snow event. While the satellite blowing snow retrieval is a useful product, further investigation is needed to reduce the uncertainties on blowing snow frequencies associated with clouds., Mathematical Geodesy and Positioning

Synergistic remote sensing of the atmosphere, combined with adaptive techniques, offers unprecedented opportunities to characterise the evolution of key atmospheric features such as the Atmospheric Boundary Layer (ABL). Using long-duration, high-resolution, profiling observations from active and passive ground-based remote sensing systems during the Verification of the Origins of Rotation in Tornadoes Experiment{Southeast (VORTEX-SE) 2017 field campaign, an attempt is made to characterise ABL development over distinct regions that are well known for their relatively high tornado frequency. In this study, observing systems include an S-band radar, Vaisala CL-31 ceilometer, Doppler Wind lidar (DWL) and radiometric observations from the Collaborative Lower Atmosphere Mobile Profiling System (CLAMPS). In this work, ABL height (ABLH) tracking over the diurnal cycle, and - up to a point - its disambiguation over selected non-precipitating case examples, are attempted. Different observational sets are used, namely, radar reflectivity observations assimilated into a Kalman filter, DWL profiles of the vertical velocity, and virtual potential temperature profiles, as well as radiosoundings and cloudbase reference information collected during Intensive Observation Periods (IOP) carried out in VORTEX-SE, Alabama during 2017. Limitations and advantages of each system are discussed., This work was supported by NOAA grants NA1501R4590232 and NA16OAR4590209, and by the Purdue University Dept. of Earth, Atmospheric, and Planetary Sciences (EAPS). CommSensLab-UPC (Excellence UnitMDM-2016-0600 funded by the Agencia Estatal de Investigación, Spain) collaborated via Spanish Gov.– EURegional Development Funds, ARS project PGC2018-094132-B-I00 and ACTRIS-PPP project GA-739530. The Spanish National Science Foundation (Ministerio de Ciencia, Innovación y Universidades) funded doctoral grant PRE2018-086054 hold by M.P. Araujo da Silva., Peer Reviewed, Postprint (published version)

In this study, four and a half months of ceilometer data from Östergarnsholm are used to analyze cloud related to processes in the boundary layer. Measurements are divided into two categories, which are defined by wind direction: a continental and a marine sector. The results show that there are significant differences in the height of the lowest cloud bases detected for the two sectors, where cloud base heights are lower for the marine wind sector during unstable and neutral conditions. The ceilometer’s ability to detect several cloud base heights simultaneously is utilized to test whether a double layer structure (DLS) can be detected. The results of this particular analysis are inconclusive as to whether a DLS has been observed or not. Detected cloud base heights differ greatly from heights suggested by the lifting condensation level (LCL). A new empirical formula for lowest cloud base height is then derived using the measurements. The Ceilometer’s estimations of sky cover are assessed to be of reasonable quality. This is suggested by computed high correlation with incoming shortwave radiation at noon for three months. However, histograms of cloud cover measurements suggest that the ceilometer tends to probably either overestimate or underestimate cloud cover. Large differences in cloud cover were observed for the two wind sectors during unstable conditions. For the months of July and August, a diurnal cycle in cloud cover for the continental wind sector was observed which suggest the presence of Stratocumulus. Measurements performed during upwelling conditions closely resemble those of the marine wind sector performed during stable conditions.

In this study, four and a half months of ceilometer data from Östergarnsholm are used to analyze cloud related to processes in the boundary layer. Measurements are divided into two categories, which are defined by wind direction: a continental and a marine sector. The results show that there are significant differences in the height of the lowest cloud bases detected for the two sectors, where cloud base heights are lower for the marine wind sector during unstable and neutral conditions. The ceilometer’s ability to detect several cloud base heights simultaneously is utilized to test whether a double layer structure (DLS) can be detected. The results of this particular analysis are inconclusive as to whether a DLS has been observed or not. Detected cloud base heights differ greatly from heights suggested by the lifting condensation level (LCL). A new empirical formula for lowest cloud base height is then derived using the measurements. The Ceilometer’s estimations of sky cover are assessed to be of reasonable quality. This is suggested by computed high correlation with incoming shortwave radiation at noon for three months. However, histograms of cloud cover measurements suggest that the ceilometer tends to probably either overestimate or underestimate cloud cover. Large differences in cloud cover were observed for the two wind sectors during unstable conditions. For the months of July and August, a diurnal cycle in cloud cover for the continental wind sector was observed which suggest the presence of Stratocumulus. Measurements performed during upwelling conditions closely resemble those of the marine wind sector performed during stable conditions.

An outstanding Saharan dust event affected the Iberian Peninsula during winter 2016 (20 to 25 February). The impact of this event on ambient PM10 surface levels and its spatial and temporal evolution was investigated by means of data from 250 air quality stations across mainland Spain and the Balearic Islands. The event had a significant impact on surface PM10 levels, and on 22 February, 90% of the air quality monitoring sites registered PM10 concentrations above the EU daily limit value of 50 µg/m3. The study of the attenuated backscattering vertical profiles associated with African dust evidenced a complex structure, with a thick aerosol layer that was at higher altitudes over the pre-Pyrenees compared to the coastal area of Barcelona but closer to the surface than typically observed at both sites. Optical and physical properties of dust particles were investigated at the continental background Global Atmosphere Watch mountain observatory of Montsec (MSA) in the pre-Pyrenees. Good agreement was found between in situ and passive remote sensing methodologies once the aloft dust layer reached the MSA station. Scattering Ångström exponent values decreased to values close to zero (even below zero for surface in situ measurements) indicating the predominance of coarse particles. On the contrary, absorption Ångström exponent values increased during the Saharan dust outbreak denoting an absorption enhancement at shorter wavelengths, characteristic of mineral dust particles. Furthermore, the performance of NMMB/BSC-Dust and BSC-DREAM8b models has been qualitatively evaluated for the dust spatial distribution across Spain and the vertical structure over MSA and Barcelona showing good agreement., Postprint (published version)

The development of the planetary boundary layer (PBL) has been studied in a complex terrain using various remote sensing and in situ techniques. The high-altitude research station at Jungfraujoch (3,580 m a.s.l.) in the Swiss Alps lies for most of the time in the free troposphere except when it is influenced by the PBL reaching the station, especially during the summer season. A ceilometer and a wind profiler were installed at Kleine Scheidegg, a mountain pass close to Jungfraujoch, located at an altitude of 2,061 m a.s.l. Data from the ceilometer were analyzed using two different algorithms, while the signal-to-noise ratio of the wind profiler was studied to compare the retrieved PBL heights. The retrieved values from the ceilometer and wind profiler agreed well during daytime and cloud-free conditions. The results were additionally compared with the PBL height estimated by the numerical weather prediction model COSMO-2, which showed a clear underestimation of the PBL height for most of the cases but occasionally also a slight overestimation especially around noon, when the PBL showed its maximum extent. Air parcels were transported upwards by slope winds towards Jungfraujoch when the PBL was higher than 2,800 m a.s.l. during cloud-free cases. This was confirmed by the in situ aerosol measurements at Jungfraujoch with a significant increase in particle number concentration, particle light absorption and scattering coefficients when PBL-influenced air masses reached the station in the afternoon hours. The continuous aerosol in situ measurements at Jungfraujoch were clearly influenced by the local PBL development but also by long-range transport phenomena such as Saharan dust or pollution from the south., AuthorCount:7

The estimation of atmospheric boundary layer height (ABLH) during a full diurnal cycle using ground-based remote sensing instruments is one of the key challenges in atmospheric science. Most of these instruments such as the lidar, the microwave radiometer (MWR), the radar, and the sodar measure one of the physical parameters, i.e., temperature, aerosol concentration, wind speed, and heat flux, within the Atmospheric Boundary Layer (ABL). All these instruments, while performing well under specific atmospheric conditions, are limited in others. Thus, an estimate of the ABLH based on the lidar return signal alone is quite good under convective conditions, where there is a clear interface between a well-mixed concentration of aerosols in the mixing layer (ML) and the free troposphere (FT). In contrast, in night-time conditions, when the convective ML recedes and a stable boundary layer (SBL) develops near the surface of the Earth, the lidar backscattered signal is usually insufficient to resolve the SBL. Similarly, a MWR is limited by its poor range resolution. In this context, a MWR-ceilometer combination is proposed. Temperature-inversion retrievals from the MWR, containing the approximate height range where the SBL is located, roughly guide the Kalman Filter based ABLH estimation algorithm for the lidar return signal, hence resulting in acceptably accurate estimates of the ABLH. The proposed approach is applied to collocated ceilometer-MWR instruments under the simple ”clear-atmosphere” cases. Radiosonde data, whenever available, is used as a reference or ”physical truth”., Peer Reviewed, Postprint (published version)

This article presents a preliminary semi-automated range-interval segmentation toolset for the identification of: 1) the apparent range of full overlap, 2) the clear-sky level (i.e., the molecular level), and cloud layers (cloud-base, cloud-peak, and cloud-top range), and 3) apparent homogeneous extinction intervals., Peer Reviewed, Postprint (published version)

© 2014 IEEE. As the adoption of embedded systems, mobiles and other smart devices keeps rising, and the scope of their involvement broadens, for instance in the enablement of Smart City-like scenarios, a pressing need emerges to tame such complexity and reuse as much tooling as possible without resorting to vertical ad-hoc solutions, while at the same time taking into account valid options with regards to infrastructure management, and other more advanced functionalities. In this sense, a widely used and competitive framework for Infrastructure as a Service such as OpenStack, with its breadth in terms of feature coverage and expanded scope, looks like fitting the bill. This work thus describes rationale, efforts, and results so far achieved, for an integration of IoT paradigms and resource ecosystems with such a kind of Cloud-oriented environment, by focusing on a Smart City scenario, and featuring data collection and visualization as example use cases of such integration.

© 2015 by the authors; licensee MDPI, Basel, Switzerland. The adoption of embedded systems, mobile devices and other smart devices keeps rising globally, and the scope of their involvement broadens, for instance, in smart city-like scenarios. In light of this, a pressing need emerges to tame such complexity and reuse as much tooling as possible without resorting to vertical ad hoc solutions, while at the same time taking into account valid options with regard to infrastructure management and other more advanced functionalities. Existing solutions mainly focus on core mechanisms and do not allow one to scale by leveraging infrastructure or adapt to a variety of scenarios, especially if actuators are involved in the loop. A new, more flexible, cloud-based approach, able to provide device-focused workflows, is required. In this sense, a widely-used and competitive framework for infrastructure as a service, such as OpenStack, with its breadth in terms of feature coverage and expanded scope, looks to fit the bill, replacing current application-specific approaches with an innovative application-agnostic one. This work thus describes the rationale, efforts and results so far achieved for an integration of IoT paradigms and resource ecosystems with such a kind of cloud-oriented device-centric environment, by focusing on a smart city scenario, namely a park smart lighting example, and featuring data collection, data visualization, event detection and coordinated reaction, as example use cases of such integration.

© 2014 IEEE. As the adoption of embedded systems, mobiles and other smart devices keeps rising, and the scope of their involvement broadens, for instance in the enablement of Smart City-like scenarios, a pressing need emerges to tame such complexity and reuse as much tooling as possible without resorting to vertical ad-hoc solutions, while at the same time taking into account valid options with regards to infrastructure management, and other more advanced functionalities. In this sense, a widely used and competitive framework for Infrastructure as a Service such as OpenStack, with its breadth in terms of feature coverage and expanded scope, looks like fitting the bill. This work thus describes rationale, efforts, and results so far achieved, for an integration of IoT paradigms and resource ecosystems with such a kind of Cloud-oriented environment, by focusing on a Smart City scenario, and featuring data collection and visualization as example use cases of such integration.

© 2015 by the authors; licensee MDPI, Basel, Switzerland. The adoption of embedded systems, mobile devices and other smart devices keeps rising globally, and the scope of their involvement broadens, for instance, in smart city-like scenarios. In light of this, a pressing need emerges to tame such complexity and reuse as much tooling as possible without resorting to vertical ad hoc solutions, while at the same time taking into account valid options with regard to infrastructure management and other more advanced functionalities. Existing solutions mainly focus on core mechanisms and do not allow one to scale by leveraging infrastructure or adapt to a variety of scenarios, especially if actuators are involved in the loop. A new, more flexible, cloud-based approach, able to provide device-focused workflows, is required. In this sense, a widely-used and competitive framework for infrastructure as a service, such as OpenStack, with its breadth in terms of feature coverage and expanded scope, looks to fit the bill, replacing current application-specific approaches with an innovative application-agnostic one. This work thus describes the rationale, efforts and results so far achieved for an integration of IoT paradigms and resource ecosystems with such a kind of cloud-oriented device-centric environment, by focusing on a smart city scenario, namely a park smart lighting example, and featuring data collection, data visualization, event detection and coordinated reaction, as example use cases of such integration.