Description and applications of a mobile system performing on-road aerosol remote sensing and in situ measurements

Abstract. The majority of ground-based aerosols observations are limited to fixed locations, narrowing the knowledge on their spatial variability. In order to overcome this issue, a compact Mobile Aerosol Monitoring System (MAMS) was developed to explore the aerosol vertical and spatial variability. This mobile laboratory is equipped with a micropulse lidar, a sun-photometer and an aerosol spectrometer. It is distinguished by other transportable platforms through its ability to perform on-road measurements and its unique feature lies in the sun-photometer capable to track the sun during motion. The system presents a great flexibility, being able to respond quickly in case of sudden aerosol events such as pollution episodes, dust, fire or volcano outbreaks. On-road mapping of aerosol physical parameters such as attenuated aerosol backscatter, aerosol optical depth, particle number and mass concentration and size distribution is achieved through the MAMS. The performance of remote sensing instruments on-board has been evaluated through intercomparison with instruments in reference networks (i.e. AERONET and EARLINET), showing that the system is capable of providing high quality data. This also illustrates the application of such system for instrument intercomparison field campaigns. Applications of the mobile system have been exemplified through two case studies in northern France. MODIS AOD data was compared to ground-based mobile sun-photometer data. A good correlation was observed with R2 of 0.76, showing the usefulness of the mobile system for validation of satellite-derived products. The performance of BSC-DREAM8b dust model has been tested by comparison of results from simulations to the lidar-sun-photometer derived extinction coefficient and mass concentration profiles. The comparison indicated that observations and model are in good agreement in describing the vertical variability of dust layers. Moreover, on-road measurements of PM10 were compared with modelled PM10 concentrations and with ATMO Hauts-de-France and AIRPARIF air quality in situ measurements, presenting an excellent agreement in horizontal spatial representativity of PM10. This proves a possible application of mobile platforms for evaluating the chemistry-models performances.

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Description and applications of a mobile system performing on-road aerosol remote sensing and in situ measurements

Atmospheric Measurement Techniques ◽

10.5194/amt-11-4671-2018 ◽

2018 ◽

Vol 11 (8) ◽

pp. 4671-4691 ◽

Cited By ~ 4

Author(s):

Ioana Elisabeta Popovici ◽

Philippe Goloub ◽

Thierry Podvin ◽

Luc Blarel ◽

Rodrigue Loisil ◽

...

Keyword(s):

Remote Sensing ◽

Spatial Variability ◽

Mass Concentration ◽

In Situ Measurements ◽

Quality Data ◽

The Sun ◽

Mobile System ◽

Modis Aod ◽

Sun Photometer

Abstract. The majority of ground-based aerosols observations are limited to fixed locations, narrowing the knowledge on their spatial variability. In order to overcome this issue, a compact Mobile Aerosol Monitoring System (MAMS) was developed to explore the aerosol vertical and spatial variability. This mobile laboratory is equipped with a micropulse lidar, a sun photometer and an aerosol spectrometer. It is distinguished from other transportable platforms through its ability to perform on-road measurements and its unique feature lies in the sun photometer's capacity for tracking the sun during motion. The system presents a great flexibility, being able to respond quickly in case of sudden aerosol events such as pollution episodes, dust, fire or volcano outbreaks. On-road mapping of aerosol physical parameters such as attenuated aerosol backscatter, aerosol optical depth, particle number and mass concentration and size distribution is achieved through the MAMS. The performance of remote sensing instruments on-board has been evaluated through intercomparison with instruments in reference networks (i.e. AERONET and EARLINET), showing that the system is capable of providing high quality data. This also illustrates the application of such a system for instrument intercomparison field campaigns. Applications of the mobile system have been exemplified through two case studies in northern France. MODIS AOD data was compared to ground-based mobile sun photometer data. A good correlation was observed with R2 of 0.76, showing the usefulness of the mobile system for validation of satellite-derived products. The performance of BSC-DREAM8b dust model has been tested by comparison of results from simulations for the lidar–sun-photometer derived extinction coefficient and mass concentration profiles. The comparison indicated that observations and the model are in good agreement in describing the vertical variability of dust layers. Moreover, on-road measurements of PM10 were compared with modelled PM10 concentrations and with ATMO Hauts-de-France and AIRPARIF air quality in situ measurements, presenting an excellent agreement in horizontal spatial representativity of PM10. This proves a possible application of mobile platforms for evaluating the chemistry-models performances.

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Comparison of the aerosol optical properties and size distribution retrieved by Sun photometer with in-situ measurements at mid-latitude

10.5194/amt-2016-97 ◽

2016 ◽

Author(s):

Aurélien Chauvigné ◽

Karine Sellegri ◽

Maxime Hervo ◽

Nadège Montoux ◽

Patrick Freville ◽

...

Keyword(s):

Remote Sensing ◽

In Situ Measurements ◽

The Sun ◽

Size Distributions ◽

Particle Size Distributions ◽

Near Surface ◽

Atmospheric Column ◽

Fine Mode ◽

Sun Photometer

Abstract. Aerosols influence the Earth radiative budget through scattering and absorption of solar radiation. Several methods are used to investigate aerosol properties and thus quantify their direct and indirect impacts on climate. At the Puy de Dôme station, continuous high altitude near surface in-situ measurements and low altitude ground-based remote sensing atmospheric column measurements give the opportunity to compare the aerosol extinction measured with both methods over a one year period. To our knowledge, it is the first time that such a comparison is realized with continuous measurements of a high altitude site during a long term period. This comparison addresses to which extend near surface in-situ measurements are representative of the whole atmospheric column, the aerosol Mixing Layer (ML), or the Free Troposphere (FT). In particular, the impact of multi aerosol layers events detected using LIDAR backscatter profiles is analysed. A good correlation between in-situ aerosol extinction coefficient and Aerosol Optical Depth (AOD) measured by the Aerosol Robotic Network (AERONET) Sun photometer is observed with a correlation coefficient around 0.80, indicating that the in-situ measurements station is representative of the overall atmospheric column. After filtering for multilayer cases and correcting for each layer optical contribution (ML and FT), the atmospheric structure seems to be the main factor influencing the comparison between the two measurement techniques. When the site lies in the ML, the in-situ extinction represents 45 % of the Sun photometer ML extinction while when the site lies within the FT, the in-situ extinction is more than two times higher than the FT Sun photometer extinction. Remote sensing retrievals of the aerosol particle size distributions (PSD) from the Sun photometer observations are then compared to the near surface in-situ measurements, at dry and at ambient relative humidities. When in-situ measurements are considered at dry state, the in-situ fine mode diameters are 44 % higher than the Sun photometer-retrieved diameters and in-situ volume concentrations are 20 % lower than of the Sun photometer-retrieved fine mode concentration. Using a parametrised hygroscopic growth factor applied to aerosol diameters, the difference between in-situ and retrieved diameters grows larger. Coarse mode in-situ diameter and concentrations show a good correlation with retrieved particle size distributions from remote sensing.

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Comparison of the aerosol optical properties and size distribution retrieved by sun photometer with in situ measurements at midlatitude

Atmospheric Measurement Techniques ◽

10.5194/amt-9-4569-2016 ◽

2016 ◽

Vol 9 (9) ◽

pp. 4569-4585 ◽

Cited By ~ 9

Author(s):

Aurélien Chauvigné ◽

Karine Sellegri ◽

Maxime Hervo ◽

Nadège Montoux ◽

Patrick Freville ◽

...

Keyword(s):

Remote Sensing ◽

High Altitude ◽

In Situ Measurements ◽

Aerosol Extinction ◽

The Sun ◽

Near Surface ◽

Atmospheric Column ◽

Fine Mode ◽

Sun Photometer

Abstract. Aerosols influence the Earth radiative budget through scattering and absorption of solar radiation. Several methods are used to investigate aerosol properties and thus quantify their direct and indirect impacts on climate. At the Puy de Dôme station, continuous high-altitude near-surface in situ measurements and low-altitude ground-based remote sensing atmospheric column measurements give the opportunity to compare the aerosol extinction measured with both methods over a 1-year period. To our knowledge, it is the first time that such a comparison is realised with continuous measurements of a high-altitude site during a long-term period. This comparison addresses to which extent near-surface in situ measurements are representative of the whole atmospheric column, the aerosol mixing layer (ML) or the free troposphere (FT). In particular, the impact of multi-aerosol layers events detected using lidar backscatter profiles is analysed. A good correlation between in situ aerosol extinction coefficient and aerosol optical depth (AOD) measured by the Aerosol Robotic Network (AERONET) sun photometer is observed with a correlation coefficient around 0.80, indicating that the in situ measurements station is representative of the overall atmospheric column. After filtering for multilayer cases and correcting for each layer optical contribution (ML and FT), the atmospheric structure seems to be the main factor influencing the comparison between the two measurement techniques. When the site lies in the ML, the in situ extinction represents 45 % of the sun photometer ML extinction while when the site lies within the FT, the in situ extinction is more than 2 times higher than the FT sun photometer extinction. Moreover, the assumption of a decreasing linear vertical aerosol profile in the whole atmosphere has been tested, significantly improving the instrumental agreement. Remote sensing retrievals of the aerosol particle size distributions (PSDs) from the sun photometer observations are then compared to the near-surface in situ measurements, at dry and at ambient relative humidities. When in situ measurements are considered at dry state, the in situ fine mode diameters are 44 % higher than the sun-photometer-retrieved diameters and in situ volume concentrations are 20 % lower than those of the sun-photometer-retrieved fine mode concentration. Using a parameterised hygroscopic growth factor applied to aerosol diameters, the difference between in situ and retrieved diameters grows larger. Coarse mode in situ diameters and concentrations show a good correlation with retrieved PSDs from remote sensing.

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Vertical profiles of aerosol mass concentration derived by unmanned airborne in situ and remote sensing instruments during dust events

Atmospheric Measurement Techniques ◽

10.5194/amt-11-2897-2018 ◽

2018 ◽

Vol 11 (5) ◽

pp. 2897-2910 ◽

Cited By ~ 11

Author(s):

Dimitra Mamali ◽

Eleni Marinou ◽

Jean Sciare ◽

Michael Pikridas ◽

Panagiotis Kokkalis ◽

...

Keyword(s):

Remote Sensing ◽

Mass Concentration ◽

Climate Models ◽

In Situ Measurements ◽

Saharan Dust ◽

Dust Particles ◽

Vertical Profiles ◽

Aerosol Mass ◽

Aerosol Mass Concentration

Abstract. In situ measurements using unmanned aerial vehicles (UAVs) and remote sensing observations can independently provide dense vertically resolved measurements of atmospheric aerosols, information which is strongly required in climate models. In both cases, inverting the recorded signals to useful information requires assumptions and constraints, and this can make the comparison of the results difficult. Here we compare, for the first time, vertical profiles of the aerosol mass concentration derived from light detection and ranging (lidar) observations and in situ measurements using an optical particle counter on board a UAV during moderate and weak Saharan dust episodes. Agreement between the two measurement methods was within experimental uncertainty for the coarse mode (i.e. particles having radii >0.5 µm), where the properties of dust particles can be assumed with good accuracy. This result proves that the two techniques can be used interchangeably for determining the vertical profiles of aerosol concentrations, bringing them a step closer towards their systematic exploitation in climate models.

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Review of manuscript entitled Description and applications of a mobile system performing on-road aerosol remote sensing and in situ measurements

10.5194/amt-2018-103-rc1 ◽

2018 ◽

Author(s):

Anonymous

Keyword(s):

Remote Sensing ◽

In Situ Measurements ◽

Mobile System ◽

Aerosol Remote Sensing

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Permafrost variability over the Northern Hemisphere based on the MERRA-2 reanalysis

The Cryosphere ◽

10.5194/tc-13-2087-2019 ◽

2019 ◽

Vol 13 (8) ◽

pp. 2087-2110 ◽

Cited By ~ 8

Author(s):

Jing Tao ◽

Randal D. Koster ◽

Rolf H. Reichle ◽

Barton A. Forman ◽

Yuan Xue ◽

...

Keyword(s):

Remote Sensing ◽

Spatial Variability ◽

Northern Hemisphere ◽

Snow Accumulation ◽

In Situ Measurements ◽

Active Layer Thickness ◽

Meteorological Forcing ◽

Northern Alaska ◽

Permafrost Regions

Abstract. This study introduces and evaluates a comprehensive, model-generated dataset of Northern Hemisphere permafrost conditions at 81 km2 resolution. Surface meteorological forcing fields from the Modern-Era Retrospective Analysis for Research and Applications 2 (MERRA-2) reanalysis were used to drive an improved version of the land component of MERRA-2 in middle-to-high northern latitudes from 1980 to 2017. The resulting simulated permafrost distribution across the Northern Hemisphere mostly captures the observed extent of continuous and discontinuous permafrost but misses the ecosystem-protected permafrost zones in western Siberia. Noticeable discrepancies also appear along the southern edge of the permafrost regions where sporadic and isolated permafrost types dominate. The evaluation of the simulated active layer thickness (ALT) against remote sensing retrievals and in situ measurements demonstrates reasonable skill except in Mongolia. The RMSE (bias) of climatological ALT is 1.22 m (−0.48 m) across all sites and 0.33 m (−0.04 m) without the Mongolia sites. In northern Alaska, both ALT retrievals from airborne remote sensing for 2015 and the corresponding simulated ALT exhibit limited skill versus in situ measurements at the model scale. In addition, the simulated ALT has larger spatial variability than the remotely sensed ALT, although it agrees well with the retrievals when considering measurement uncertainty. Controls on the spatial variability of ALT are examined with idealized numerical experiments focusing on northern Alaska; meteorological forcing and soil types are found to have dominant impacts on the spatial variability of ALT, with vegetation also playing a role through its modulation of snow accumulation. A correlation analysis further reveals that accumulated above-freezing air temperature and maximum snow water equivalent explain most of the year-to-year variability of ALT nearly everywhere over the model-simulated permafrost regions.

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Aerosol absorption profiling from the synergy of lidar and sun-photometry: the ACTRIS-2 campaigns in Germany, Greece and Cyprus

EPJ Web of Conferences ◽

10.1051/epjconf/201817608005 ◽

2018 ◽

Vol 176 ◽

pp. 08005 ◽

Cited By ~ 2

Author(s):

Alexandra Tsekeri ◽

Vassilis Amiridis ◽

Anton Lopatin ◽

Eleni Marinou ◽

Eleni Giannakaki ◽

...

Keyword(s):

Remote Sensing ◽

Radiative Transfer ◽

Absorption Coefficient ◽

Single Scattering ◽

In Situ Measurements ◽

Climate Modelling ◽

Aerosol Absorption ◽

Sun Photometer ◽

Remote Sensing Techniques

Aerosol absorption profiling is crucial for radiative transfer calculations and climate modelling. Here, we utilize the synergy of lidar with sun-photometer measurements to derive the absorption coefficient and single scattering albedo profiles during the ACTRIS-2 campaigns held in Germany, Greece and Cyprus. The remote sensing techniques are compared with in situ measurements in order to harmonize and validate the different methodologies and reduce the absorption profiling uncertainties.

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