scholarly journals Multi-Sensor Observation of a Saharan Dust Outbreak over Transylvania, Romania in April 2019

Atmosphere ◽  
2020 ◽  
Vol 11 (4) ◽  
pp. 364 ◽  
Author(s):  
Nicolae Ajtai ◽  
Horațiu Ștefănie ◽  
Alexandru Mereuță ◽  
Andrei Radovici ◽  
Camelia Botezan
Keyword(s):  
Complex Analysis ◽  
Remote Sensing Data ◽  
Ground Level ◽  
Global Scale ◽  
Saharan Dust ◽  
Back Trajectories ◽  
Microphysical Properties ◽  
Multi Wavelength ◽  
Degree Of Certainty

Mineral aerosols are considered to be the second largest source of natural aerosol, the Saharan desert being the main source of dust at global scale. Under certain meteorological conditions, Saharan dust can be transported over large parts of Europe, including Romania. The aim of this paper is to provide a complex analysis of a Saharan dust outbreak over the Transylvania region of Romania, based on the synergy of multiple ground-based and satellite sensors in order to detect the dust intrusion with a higher degree of certainty. The measurements were performed during the peak of the outbreak on April the 24th 2019, with instruments such as a Cimel sun-photometer and a multi-wavelength Raman depolarization lidar, together with an in-situ particle counter measuring at ground level. Remote sensing data from MODIS sensors on Terra and Aqua were also analyzed. Results show the presence of dust aerosol layers identified by the multi-wavelength Raman and depolarization lidar at altitudes of 2500–4000 m, and 7000 m, respectively. The measured optical and microphysical properties, together with the HYSPLIT back-trajectories, NMMB/BSC dust model, and synoptic analysis, confirm the presence of lofted Saharan dust layers over Cluj-Napoca, Romania. The NMMB/BSC dust model predicted dust load values between 1 and 1.5 g/m2 over Cluj-Napoca at 12:00 UTC for April the 24th 2019. Collocated in-situ PM monitoring showed that dry deposition was low, with PM10 and PM2.5 concentrations similar to the seasonal averages for Cluj-Napoca.

scholarly journals Study of aerosol microphysical properties profiles retrieved from ground-based remote sensing and aircraft in-situ measurements during a Saharan dust event

2015 ◽  
Vol 8 (9) ◽  
pp. 9289-9338 ◽  
Author(s):  
M. J. Granados-Muñoz ◽  
J. A. Bravo-Aranda ◽  
D. Baumgardner ◽  
J. L. Guerrero-Rascado ◽  
D. Pérez-Ramírez ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Volume Concentration ◽  
Mineral Dust ◽  
In Situ Measurements ◽  
Saharan Dust ◽  
Night Time ◽  
Passive Remote Sensing ◽  
Microphysical Properties ◽  
Multi Wavelength

Abstract. In this work we present an analysis of mineral dust optical and microphysical properties obtained from different retrieval techniques applied to active and passive remote sensing measurements, including a comparison with simultaneous in-situ aircraft measurements. Data were collected in a field campaign performed during a mineral dust outbreak a Granada, Spain, experimental site (37.16° N, 3.61° W, 680 m a.s.l.) on the 27 June 2011. Column-integrated properties are provided by sun- and star-photometry which allows a continuous evaluation of the mineral dust optical properties during both day and night-time. Both the Linear Estimation and AERONET (Aerosol Robotic Network) inversion algorithms are applied for the retrieval of the column-integrated microphysical particle properties. In addition, vertically-resolved microphysical properties are obtained from a multi-wavelength Raman lidar system included in EARLINET (European Aerosol Research Lidar Network), by using both LIRIC (Lidar Radiometer Inversion Code) algorithm during daytime and an algorithm applied to the Raman measurements based on the regularization technique during night-time. LIRIC retrievals reveal several dust layers between 3 and 5 km a.s.l. with volume concentrations of the coarse spheroid mode up to 60 μm3 cm−3. The combined use of the regularization and LIRIC methods reveals the night-to-day evolution of the vertical structure of the mineral dust microphysical properties and offers complementary information to that from column-integrated variables retrieved from passive remote sensing. Additionally, lidar depolarization profiles and LIRIC retrieved volume concentration are compared with aircraft in-situ measurements. This study presents for the first time a comparison of both volume concentration and dust particle polarization ratios measured with in-situ and remote sensing techniques. Results for the depolarization measurements in the dust layer indicate reasonable agreement within the estimated uncertainties. The differences in the volume concentration profiles, although somewhat larger, are still within the expected uncertainties.

scholarly journals Synergetic monitoring of Saharan dust plumes and potential impact on surface: a case study of dust transport from Canary Islands to Iberian Peninsula

2011 ◽  
Vol 11 (7) ◽  
pp. 3067-3091 ◽  
Author(s):  
C. Córdoba-Jabonero ◽  
M. Sorribas ◽  
J. L. Guerrero-Rascado ◽  
J. A. Adame ◽  
Y. Hernández ◽  
...  
Keyword(s):  
Iberian Peninsula ◽  
Particle Deposition ◽  
Ground Level ◽  
In Situ Measurements ◽  
Saharan Dust ◽  
Dust Transport ◽  
Air Masses ◽  
Potential Impact

Abstract. The synergetic use of meteorological information, remote sensing both ground-based active (lidar) and passive (sun-photometry) techniques together with backtrajectory analysis and in-situ measurements is devoted to the characterization of dust intrusions. A case study of air masses advected from the Saharan region to the Canary Islands and the Iberian Peninsula, located relatively close and far away from the dust sources, respectively, was considered for this purpose. The observations were performed over three Spanish geographically strategic stations within the dust-influenced area along a common dust plume pathway monitored from 11 to 19 of March 2008. A 4-day long dust event (13–16 March) over the Santa Cruz de Tenerife Observatory (SCO), and a linked short 1-day dust episode (14 March) in the Southern Iberian Peninsula over the Atmospheric Sounding Station "El Arenosillo" (ARN) and the Granada station (GRA) were detected. Meteorological conditions favoured the dust plume transport over the area under study. Backtrajectory analysis clearly revealed the Saharan region as the source of the dust intrusion. Under the Saharan air masses influence, AERONET Aerosol Optical Depth at 500 nm (AOD500) ranged from 0.3 to 0.6 and Ångström Exponent at 440/675 nm wavelength pair (AE440/675) was lower than 0.5, indicating a high loading and predominance of coarse particles during those dusty events. Lidar observations characterized their vertical layering structure, identifying different aerosol contributions depending on altitude. In particular, the 3-km height dust layer transported from the Saharan region and observed over SCO site was later on detected at ARN and GRA stations. No significant differences were found in the lidar (extinction-to-backscatter) ratio (LR) estimation for that dust plume over all stations when a suitable aerosol scenario for lidar data retrieval is selected. Lidar-retrieved LR values of 60–70 sr were obtained during the main dust episodes. These similar LR values found in all the stations suggest that dust properties were kept nearly unchanged in the course of its medium-range transport. In addition, the potential impact on surface of that Saharan dust intrusion over the Iberian Peninsula was evaluated by means of ground-level in-situ measurements for particle deposition assessment together with backtrajectory analysis. However, no connection between those dust plumes and the particle sedimentation registered at ground level is found. Differences on particle deposition processes observed in both Southern Iberian Peninsula sites are due to the particular dust transport pattern occurred over each station. Discrepancies between columnar-integrated and ground-level in-situ measurements show a clear dependence on height of the dust particle size distribution. Then, further vertical size-resolved observations are needed for evaluation of the impact on surface of the Saharan dust arrival to the Iberian Peninsula.

scholarly journals Multi-wavelength Raman lidar, sunphotometric and aircraft measurements in combination with inversion models for the estimation of the aerosol optical and physico-chemical properties over Athens, Greece

2012 ◽  
Vol 5 (1) ◽  
pp. 589-625
Author(s):  
R. E. Mamouri ◽  
A. Papayannis ◽  
V. Amiridis ◽  
D. Müller ◽  
P. Kokkalis ◽  
...  
Keyword(s):  
Water Vapor ◽  
Chemical Properties ◽  
Urban Site ◽  
Aircraft Measurements ◽  
Raman Lidar ◽  
Lidar System ◽  
Aerosol Composition ◽  
Microphysical Properties ◽  
Multi Wavelength

Abstract. A novel procedure has been developed to retrieve, simultaneously, the optical, microphysical and chemical properties of tropospheric aerosols with a multi-wavelength Raman lidar system in the troposphere over an urban site (Athens, Greece: 37.9° N, 23.6° E, 200 m a.s.l.) using data obtained during the European Space Agency (ESA) THERMOPOLIS project which took place between 15–31 July 2009 over the Greater Athens Area (GAA). We selected to apply our procedure for a case study of intense aerosol layers occurred on 20–21 July 2009. The National Technical University of Athens (NTUA) EOLE 6-wavelength Raman lidar system has been used to provide the vertical profiles of the optical properties of aerosols (extinction and backscatter coefficients, lidar ratio) and the water vapor mixing ratio. An inversion algorithm was used to derive the mean aerosol microphysical properties (mean effective radius – reff), single-scattering albedo (ω) and mean complex refractive index (m) at selected heights in the 2–3 km height region. We found that reff was 0.3–0.4 μm, ω at 532 nm ranged from 0.63 to 0.88 and m ranged from 1.45 + 0.015i to 1.56 + 0.05i, in good accordance with in situ aircraft measurements. The final data set of the aerosol microphysical properties along with the water vapor and temperature profiles were incorporated into the ISORROPIA model to infer an in situ aerosol composition consistent with the retrieved m and ω values. The retrieved aerosol chemical composition in the 2–3 km height region gave a variable range of sulfate (0–60%) and organic carbon (OC) content (0–50%), although the OC content increased (up to 50%) and the sulfate content dropped (up to 30%) around 3 km height; in connection with the retrieved low ω value (0.63), indicates the presence of absorbing biomass burning smoke mixed with urban haze. Finally, the retrieved aerosol microphysical properties were compared with column-integrated sunphotometer data.

scholarly journals Accomplishments of the MUSICA project to provide accurate, long-term, global and high-resolution observations of tropospheric {H<sub>2</sub>O,<i>δ</i>D} pairs – a review

2016 ◽  
Vol 9 (7) ◽  
pp. 2845-2875 ◽  
Author(s):  
Matthias Schneider ◽  
Andreas Wiegele ◽  
Sabine Barthlott ◽  
Yenny González ◽  
Emanuel Christner ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Measurement Techniques ◽  
Remote Sensing Data ◽  
Global Scale ◽  
Horizontal Resolution ◽  
Atmospheric Composition ◽  
Remote Sensing Techniques ◽  
Middle Infrared

Abstract. In the lower/middle troposphere, {H2O,δD} pairs are good proxies for moisture pathways; however, their observation, in particular when using remote sensing techniques, is challenging. The project MUSICA (MUlti-platform remote Sensing of Isotopologues for investigating the Cycle of Atmospheric water) addresses this challenge by integrating the remote sensing with in situ measurement techniques. The aim is to retrieve calibrated tropospheric {H2O,δD} pairs from the middle infrared spectra measured from ground by FTIR (Fourier transform infrared) spectrometers of the NDACC (Network for the Detection of Atmospheric Composition Change) and the thermal nadir spectra measured by IASI (Infrared Atmospheric Sounding Interferometer) aboard the MetOp satellites. In this paper, we present the final MUSICA products, and discuss the characteristics and potential of the NDACC/FTIR and MetOp/IASI {H2O,δD} data pairs. First, we briefly resume the particularities of an {H2O,δD} pair retrieval. Second, we show that the remote sensing data of the final product version are absolutely calibrated with respect to H2O and δD in situ profile references measured in the subtropics, between 0 and 7 km. Third, we reveal that the {H2O,δD} pair distributions obtained from the different remote sensors are consistent and allow distinct lower/middle tropospheric moisture pathways to be identified in agreement with multi-year in situ references. Fourth, we document the possibilities of the NDACC/FTIR instruments for climatological studies (due to long-term monitoring) and of the MetOp/IASI sensors for observing diurnal signals on a quasi-global scale and with high horizontal resolution. Fifth, we discuss the risk of misinterpreting {H2O,δD} pair distributions due to incomplete processing of the remote sensing products.

scholarly journals The 1-way on-line coupled model system MECO(n) – Part 4: Chemical evaluation (based on MESSy v2.52)

2016 ◽  
Author(s):  
Mariano Mertens ◽  
Astrid Kerkweg ◽  
Patrick Jöckel ◽  
Holger Tost ◽  
Christiane Hofmann
Keyword(s):  
Atmospheric Chemistry ◽  
Coupled Model ◽  
Ground Level ◽  
Global Scale ◽  
Model System ◽  
Scale Down ◽  
On Line ◽  
In Situ Observations ◽  
Line Coupling

Abstract. For the first time a simulation incorporating tropospheric and stratospheric chemistry using the newly developed MECO(n) model system is performed. MECO(n) is short for MESSyfied ECHAM and COSMO model nested n-times. It features an on-line coupling of the COSMO-CLM model, equipped with the Modular Earth Submodel System (MESSy) interface (called COSMO/MESSy), with the global atmospheric chemistry model ECHAM5/MESSy for Atmospheric Chemistry (EMAC). This on-line coupling allows a consistent model chain with respect to chemical and meteorological boundary conditions from the global scale down to the regional kilometre scale. A MECO(2) simulation incorporating one regional instance over Europe with 50 km resolution and a one instance over Germany with 12 km resolution is conducted for the evaluation of MECO(n) with respect to tropospheric gas-phase chemistry. The main goal of this evaluation is to ensure, that the chemistry related MESSy submodels and the on-line coupling with respect to the chemistry are correctly implemented. This evaluation is a prerequisite for the further usage of MECO(n) in atmospheric chemistry related studies. Results of EMAC and the two COSMO/MESSy instances are compared with satellite-, ground-based- and aircraft in situ observations, focusing on ozone, carbon monoxide and nitrogen dioxide. Further the methane lifetimes in EMAC and the two COSMO/MESSy instances are analysed in view of the tropospheric oxidation capacity. From this evaluation we conclude that the chemistry related submodels and the on-line coupling with respect to the chemistry are correctly implemented. In comparison with observations both, EMAC and COSMO/MESSy, show strengths and weaknesses. Especially in comparison to aircraft in situ observations COSMO/MESSy shows very promising results. However, the amplitude of the diurnal cycle of ground-level ozone measurements is underestimated. Most of the differences between COSMO/MESSy and EMAC can be attributed to differences in the dynamics of both models, which is subject to further model developments.

Global in-situ cloud phase observations during the airborne Atmospheric Tomography mission and A-LIFE field experiment

2021 ◽  
Author(s):  
Maximilian Dollner ◽  
Josef Gasteiger ◽  
Manuel Schöberl ◽  
Glenn Diskin ◽  
T. Paul Bui ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Field Experiment ◽  
Global Scale ◽  
Systematic Sampling ◽  
The Novel ◽  
Microphysical Properties ◽  
The Pacific ◽  
Cloud Microphysical Processes ◽  
Microphysical Processes

&lt;p&gt;Clouds are an important contributor to the uncertainty of future climate predictions, partly because cloud microphysical processes are still not fully understood. Interhemispheric observations, providing a dataset to investigate these cloud microphysical processes, are surprisingly rare - in particular observations using the same instrumentation on a global scale.&lt;/p&gt;&lt;p&gt;Between 2016 and 2018, the ATom (Atmospheric Tomography; 2016-2018) mission and the A-LIFE (Absorbing aerosol layers in a changing climate: aging, lifetime and dynamics; 2017) field experiment performed extensive airborne in-situ measurements of aerosol and cloud microphysical properties in the atmosphere up to approx. 13km altitude on a global scale. Profiling of the remote atmosphere over the Pacific and Atlantic Oceans from about 80&amp;#176;N to 86&amp;#176;S during ATom and systematic sampling of the region in the Mediterranean during A-LIFE provides a combined dataset of nearly 60h of measurements inside clouds.&lt;/p&gt;&lt;p&gt;We developed a novel cloudindicator algorithm, which utilizes measurements of a second-generation Cloud, Aerosol and Precipitation Spectrometer (CAPS, Droplet Measurement Technologies), relative humidity and temperature. It automatically detects clouds and classifies them according to their cloud phase.&lt;/p&gt;&lt;p&gt;In this study we present the novel cloudindicator algorithm and the combined dataset of ATom and A-LIFE global scale in-situ cloud observations. Furthermore, we show results of the cloud phase analysis of the extensive dataset.&lt;/p&gt;

scholarly journals Multi-wavelength Raman lidar, sun photometric and aircraft measurements in combination with inversion models for the estimation of the aerosol optical and physico-chemical properties over Athens, Greece

2012 ◽  
Vol 5 (7) ◽  
pp. 1793-1808 ◽  
Author(s):  
R. E. Mamouri ◽  
A. Papayannis ◽  
V. Amiridis ◽  
D. Müller ◽  
P. Kokkalis ◽  
...  
Keyword(s):  
Water Vapor ◽  
Chemical Properties ◽  
Urban Site ◽  
Aircraft Measurements ◽  
Raman Lidar ◽  
Lidar System ◽  
Aerosol Composition ◽  
Microphysical Properties ◽  
Multi Wavelength

Abstract. A novel procedure has been developed to retrieve, simultaneously, the optical, microphysical and chemical properties of tropospheric aerosols with a multi-wavelength Raman lidar system in the troposphere over an urban site (Athens, Greece: 37.9° N, 23.6° E, 200 m a.s.l.) using data obtained during the European Space Agency (ESA) THERMOPOLIS project, which took place between 15–31 July 2009 over the Greater Athens Area (GAA). We selected to apply our procedure for a case study of intense aerosol layers that occurred on 20–21 July 2009. The National Technical University of Athens (NTUA) EOLE 6-wavelength Raman lidar system has been used to provide the vertical profiles of the optical properties of aerosols (extinction and backscatter coefficients, lidar ratio) and the water vapor mixing ratio. An inversion algorithm was used to derive the mean aerosol microphysical properties (mean effective radius (reff), single-scattering albedo ω) and mean complex refractive index (m)) at selected heights in the 2–3 km height region. We found that reff was 0.14–0.4 (±0.14) μm, ω was 0.63–0.88 (±0.08) (at 532 nm) and m ranged from 1.44 (±0.10) + 0.01 (±0.01)i to 1.55 (±0.12) + 0.06 (±0.02)i, in good agreement (only for the reff values) with in situ aircraft measurements. The water vapor and temperature profiles were incorporated into the ISORROPIA II model to propose a possible in situ aerosol composition consistent with the retrieved m and ω values. The retrieved aerosol chemical composition in the 2–3 km height region gave a variable range of sulfate (0–60%) and organic carbon (OC) content (0–50%), although the OC content increased (up to 50%) and the sulfate content dropped (up to 30%) around 3 km height; the retrieved low ω value (0.63), indicates the presence of absorbing biomass burning smoke mixed with urban haze. Finally, the retrieved aerosol microphysical properties were compared with column-integrated sun photometer CIMEL data.

Evaluation the MOD10A1 daily snow albedo product (v. 6) on Livingston Island, Antarctica

2020 ◽  
Author(s):  
Alejandro Corbea-Pérez ◽  
Javier Fernández-Calleja ◽  
Carmen Recondo ◽  
Susana Fernández
Keyword(s):  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Remote Sensing Data ◽  
Global Scale ◽  
Sensor Calibration ◽  
Satellite Measurements ◽  
Snow Albedo ◽  
Livingston Island ◽  
Increasing Trend

&lt;p&gt;One of the factors that can most influence climate changes on a global scale is the albedo decrease, associated with a temperature increase and a snow cover decrease, mainly in the polar areas, where the remote sensing data are essential because there is much difficulty access to obtain measurements in situ. Therefore, evaluations of satellite measurements are essential.&lt;/p&gt;&lt;p&gt;The daily MOD10A1 snow product provides daily measurements of albedo. Version 6 is currently available. In Antarctica, and more specifically on Livingston Island (South Shetland Archipelago), where one of the Spanish Antarctic bases is located, the daily snow albedo product of MODIS (MOD10A1) has been evaluated using version 5 data (Calleja et al. 2019). However, several authors have recommended updating the analyses based on version 6 data (Box et al. 2012, Casey et al. 2017), as they are more accurate.&lt;/p&gt;&lt;p&gt;In this work, we have analyzed the albedo behavior using MOD10A1 version 6 data between 2006 and 2015 and we have seen an increasing trend of albedo. Version 5 showed an increase of 0.07 per decade. However, version 6 data show less variability (0.04 per decade), and its results are closer to those obtained in the measurements in situ (0.03 per decade). In addition, the results obtained allow us to affirm that the MOD10A1 daily albedo product (v. 6) can be used to determine the albedo in the study area.&lt;/p&gt;&lt;p&gt;References:&lt;/p&gt;&lt;p&gt;Box, J. E., Fettweis, X., Stroeve, J. C., Tedesco, M., Hall, D. K., &amp; Steffen, K. (2012). Greenland ice sheet albedo feedback: thermodynamics and atmospheric drivers. The Cryosphere, 6(4), 821-839.&lt;/p&gt;&lt;p&gt;Calleja, J. F., Corbea-P&amp;#233;rez, A., Fern&amp;#225;ndez, S., Recondo, C., Pe&amp;#243;n, J., &amp; de Pablo, M. &amp;#193;. (2019). Snow Albedo Seasonality and Trend from MODIS Sensor and Ground Data at Johnsons Glacier, Livingston Island, Maritime Antarctica. Sensors, 19(16), 3569.&lt;/p&gt;&lt;p&gt;Casey, K. A., Polashenski, C. M., Chen, J., &amp; Tedesco, M. (2017). Impact of MODIS sensor calibration updates on Greenland Ice Sheet surface reflectance and albedo trends. The Cryosphere, 11(4), 1781-1795.&lt;/p&gt;

scholarly journals Desert Dust Outbreaks over Mediterranean Basin: A Modeling, Observational, and Synoptic Analysis Approach

2012 ◽  
Vol 2012 ◽  
pp. 1-14 ◽  
Author(s):  
F. Calastrini ◽  
F. Guarnieri ◽  
S. Becagli ◽  
C. Busillo ◽  
M. Chiari ◽  
...  
Keyword(s):  
Mediterranean Basin ◽  
Ad Hoc ◽  
Ground Level ◽  
Saharan Dust ◽  
Dust Particles ◽  
Pixe Analysis ◽  
Synoptic Analysis ◽  
Physical And Chemical ◽  
Model Chain

Dust intrusions from African desert regions have an impact on the Mediterranean Basin (MB), as they cause an anomalous increase of aerosol concentrations in the tropospheric column and often an increase of particulate matter at the ground level. To estimate the Saharan dust contribution to PM10, a significant dust intrusion event that occurred in June 2006 is investigated, joining numerical simulations and specific measurements. As a first step, a synoptic analysis of this episode is performed. Such analysis, based only on meteorological and aerosol optical thickness observations, does not allow the assessment of exhaustive informations. In fact, it is not possible to distinguish dust outbreaks transported above the boundary layer without any impact at the ground level from those causing deposition. The approach proposed in this work applies an ad hoc model chain to describe emission, transport and deposition dynamics. Furthermore, physical and chemical analyses (PIXE analysis and ion chromatography) were used to measure the concentration of all soil-related elements to quantify the contribution of dust particles to PM10. The comparison between simulation results and in-situ measurements show a satisfying agreement, and supports the effectiveness of the model chain to estimate the Saharan dust contribution at ground level.

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