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Aerosol optical depth retrievals in central Amazonia from a multi-filter rotating shadow-band radiometer calibrated on-site
- Source :
- Atmospheric Measurement Techniques, Vol 12, Pp 921-934 (2019), Repositório Institucional da USP (Biblioteca Digital da Produção Intelectual), Universidade de São Paulo (USP), instacron:USP
- Publication Year :
- 2019
- Publisher :
- Copernicus Publications, 2019.
-
Abstract
- Extraterrestrial spectral response calibration of a multi-filter rotating shadow band radiometer (MFRSR) under pristine Amazonian Forest atmosphere conditions was performed using the Langley plot method. The MFRSR is installed in central Amazonia as part of a long-term monitoring site, which was used in the context of the GoAmazon2014/5 experiment. It has been operating continuously since 2011 without regular extraterrestrial calibration, preventing its application to accurate monitoring of aerosol particles. Once calibrated, the MFRSR measurements were applied to retrieve aerosol particle columnar optical properties, specifically aerosol optical depth (AODλ) and Ångström exponent (AE), which were evaluated against retrievals from a collocated Cimel Sun photometer belonging to the AErosol RObotic NETwork (AERONET). Results obtained revealed that pristine Amazonian conditions are able to provide MFRSR extraterrestrial spectral response with relative uncertainty lower than 1.0 % in visible channels. The worst estimate (air mass =1) for absolute uncertainty in AODλ retrieval varied from ≈0.02 to ≈0.03, depending on the assumption regarding uncertainty for MFRSR direct normal irradiance measured at the surface. The obtained root mean square error (RMSE ≈0.025) from the evaluation of MFRSR retrievals against AERONET AODλ was, in general, lower than estimated MFRSR AODλ uncertainty, and close to the uncertainty of AERONET field Sun photometers (≈0.02).
- Subjects :
- Atmospheric Science
Angstrom exponent
Radiometer
010504 meteorology & atmospheric sciences
lcsh:TA715-787
lcsh:Earthwork. Foundations
Context (language use)
Photometer
010501 environmental sciences
01 natural sciences
Aerosol
law.invention
AERONET
lcsh:Environmental engineering
Sun photometer
RADIÔMETROS
law
Calibration
Environmental science
lcsh:TA170-171
0105 earth and related environmental sciences
Remote sensing
Subjects
Details
- Language :
- English
- ISSN :
- 18678548 and 18671381
- Volume :
- 12
- Database :
- OpenAIRE
- Journal :
- Atmospheric Measurement Techniques
- Accession number :
- edsair.doi.dedup.....911f9cab270afe22c0f59ad2e7279bfa