scholarly journals Air quality in the Galapagos Islands: A baseline view from remote sensing and in situ measurements

2020 ◽  
Vol 27 (1) ◽  
Author(s):  
María Cazorla ◽  
Edgar Herrera
Keyword(s):  
Remote Sensing ◽  
Air Quality ◽  
Galapagos Islands ◽  
In Situ Measurements ◽  
Galápagos Islands

scholarly journals High resolution NO<sub>2</sub> remote sensing from the Airborne Prism EXperiment (APEX) imaging spectrometer

2012 ◽  
Vol 5 (2) ◽  
pp. 2449-2486 ◽  
Author(s):  
C. Popp ◽  
D. Brunner ◽  
A. Damm ◽  
M. Van Roozendael ◽  
C. Fayt ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Air Quality ◽  
Spatial Resolution ◽  
In Situ Measurements ◽  
High Signal ◽  
Waste Incinerator ◽  
Imaging Spectrometer ◽  
Airborne Measurements ◽  
Spectrometer Data

Abstract. We present and evaluate the retrieval of high spatial resolution maps of NO2 vertical column densities (VCD) from the Airborne Prism EXperiment (APEX) imaging spectrometer. APEX is a novel instrument providing airborne measurements of unique spectral and spatial resolution and coverage as well as high signal stability. In this study, we use spectrometer data acquired over Zurich, Switzerland, in the morning and late afternoon during a flight campaign on a cloud-free summer day in June 2010. NO2 VCD are derived with a two-step approach usually applied to satellite NO2 retrievals, i.e. a DOAS analysis followed by air mass factor calculations based on radiative transfer computations. Our analysis demonstrates that APEX is clearly sensitive to NO2 VCD above typical European tropospheric background abundances (>1 × 1015 molec cm−2). The two-dimensional maps of NO2 VCD reveal a very plausible spatial distribution with strong gradients around major NOx sources (e.g. Zurich airport, waste incinerator, motorways) and low NO2 in remote areas. The morning overflights resulted in generally higher NO2 VCD and a more distinct pattern than the afternoon overflights which can be attributed to the meteorological conditions prevailing during that day (development of the boundary layer and increased wind speed in the afternoon) as well as to photochemical loss of NO2. The remotely sensed NO2 VCD are also highly correlated with ground-based in-situ measurements from local and national air quality networks (R=0.73). Airborne NO2 remote sensing using APEX will be valuable to detect NO2 emission sources, to provide input for NO2 emission modeling, and to establish links between in-situ measurements, air quality models, and satellite NO2 products.

scholarly journals High-resolution NO<sub>2</sub> remote sensing from the Airborne Prism EXperiment (APEX) imaging spectrometer

2012 ◽  
Vol 5 (9) ◽  
pp. 2211-2225 ◽  
Author(s):  
C. Popp ◽  
D. Brunner ◽  
A. Damm ◽  
M. Van Roozendael ◽  
C. Fayt ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Air Quality ◽  
Spatial Resolution ◽  
In Situ Measurements ◽  
High Signal ◽  
Waste Incinerator ◽  
Imaging Spectrometer ◽  
Airborne Measurements ◽  
Spectrometer Data

Abstract. We present and evaluate the retrieval of high spatial resolution maps of NO2 vertical column densities (VCD) from the Airborne Prism EXperiment (APEX) imaging spectrometer. APEX is a novel instrument providing airborne measurements of unique spectral and spatial resolution and coverage as well as high signal stability. In this study, we use spectrometer data acquired over Zurich, Switzerland, in the morning and late afternoon during a flight campaign on a cloud-free summer day in June 2010. NO2 VCD are derived with a two-step approach usually applied to satellite NO2 retrievals, i.e. a DOAS analysis followed by air mass factor calculations based on radiative transfer computations. Our analysis demonstrates that APEX is clearly sensitive to NO2 VCD above typical European tropospheric background abundances (>1 × 1015 molec cm−2). The two-dimensional maps of NO2 VCD reveal a very convincing spatial distribution with strong gradients around major NOx sources (e.g. Zurich airport, waste incinerator, motorways) and low NO2 in remote areas. The morning overflights resulted in generally higher NO2 VCD and a more distinct pattern than the afternoon overflights which can be attributed to the meteorological conditions prevailing during that day with stronger winds and hence larger dilution in the afternoon. The remotely sensed NO2 VCD are also in reasonably good agreement with ground-based in-situ measurements from air quality networks considering the limitations of comparing column integrals with point measurements. Airborne NO2 remote sensing using APEX will be valuable to detect NO2 emission sources, to provide input for NO2 emission modelling, and to establish links between in-situ measurements, air quality models, and satellite NO2 products.

Particulate matter variability in Kathmandu based on in-situ measurements, remote sensing, and reanalysis data

2021 ◽  
pp. 105623
Author(s):  
Stefan Becker ◽  
Ramesh Prasad Sapkota ◽  
Binod Pokharel ◽  
Loknath Adhikari ◽  
Rudra Prasad Pokhrel ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Particulate Matter ◽  
Reanalysis Data ◽  
In Situ Measurements

scholarly journals Aerosol optical and microphysical retrievals from a hybrid multiwavelength lidar data set – DISCOVER-AQ 2011

2014 ◽  
Vol 7 (9) ◽  
pp. 3095-3112 ◽  
Author(s):  
P. Sawamura ◽  
D. Müller ◽  
R. M. Hoff ◽  
C. A. Hostetler ◽  
R. A. Ferrare ◽  
...  
Keyword(s):  
Remote Sensing ◽  
In Situ Measurements ◽  
Index Of Refraction ◽  
High Spectral Resolution ◽  
Lidar Data ◽  
Data Set ◽  
Microphysical Properties ◽  
Lidar Measurements ◽  
Multiwavelength Lidar

Abstract. Retrievals of aerosol microphysical properties (effective radius, volume and surface-area concentrations) and aerosol optical properties (complex index of refraction and single-scattering albedo) were obtained from a hybrid multiwavelength lidar data set for the first time. In July 2011, in the Baltimore–Washington DC region, synergistic profiling of optical and microphysical properties of aerosols with both airborne (in situ and remote sensing) and ground-based remote sensing systems was performed during the first deployment of DISCOVER-AQ. The hybrid multiwavelength lidar data set combines ground-based elastic backscatter lidar measurements at 355 nm with airborne High-Spectral-Resolution Lidar (HSRL) measurements at 532 nm and elastic backscatter lidar measurements at 1064 nm that were obtained less than 5 km apart from each other. This was the first study in which optical and microphysical retrievals from lidar were obtained during the day and directly compared to AERONET and in situ measurements for 11 cases. Good agreement was observed between lidar and AERONET retrievals. Larger discrepancies were observed between lidar retrievals and in situ measurements obtained by the aircraft and aerosol hygroscopic effects are believed to be the main factor in such discrepancies.

scholarly journals The Ship Detection Using Airborne and In-situ Measurements Based on Hyperspectral Remote Sensing

2017 ◽  
Vol 38 (7) ◽  
pp. 535-545 ◽  
Author(s):  
Jae-Jin Park ◽  
◽  
Sangwoo Oh ◽  
Kyung-Ae Park ◽  
Pierre-Yves Foucher ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Hyperspectral Remote Sensing ◽  
In Situ Measurements ◽  
Ship Detection

scholarly journals ESTIMATION OF SURFACE SNOW WETNESS USING SENTINEL-2 MULTISPECTRAL DATA

2018 ◽  
Vol IV-5 ◽  
pp. 223-228 ◽  
Author(s):  
D. Varade ◽  
O. Dikshit
Keyword(s):  
Remote Sensing ◽  
Water Resource Management ◽  
Remote Sensing Data ◽  
Microwave Remote Sensing ◽  
In Situ Measurements ◽  
Physical Relationship ◽  
Sensing Data ◽  
Surface Snow ◽  
Sentinel 2

<p><strong>Abstract.</strong> Snow cover characterization and estimation of snow geophysical parameters is a significant area of research in water resource management and surface hydrological processes. With advances in spaceborne remote sensing, much progress has been achieved in the qualitative and quantitative characterization of snow geophysical parameters. However, most of the methods available in the literature are based on the microwave backscatter response of snow. These methods are mostly based on the remote sensing data available from active microwave sensors. Moreover, in alpine terrains, such as in the Himalayas, due to the geometrical distortions, the missing data is significant in the active microwave remote sensing data. In this paper, we present a methodology utilizing the multispectral observations of Sentinel-2 satellite for the estimation of surface snow wetness. The proposed approach is based on the popular triangle method which is significantly utilized for the assessment of soil moisture. In this case, we develop a triangular feature space using the near infrared (NIR) reflectance and the normalized differenced snow index (NDSI). Based on the assumption that the NIR reflectance is linearly related to the liquid water content in the snow, we derive a physical relationship for the estimation of snow wetness. The modeled estimates of snow wetness from the proposed approach were compared with in-situ measurements of surface snow wetness. A high correlation determined by the coefficient of determination of 0.94 and an error of 0.535 was observed between the proposed estimates of snow wetness and in-situ measurements.</p>

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