TY  - JOUR
AU  - Almansa, A.F.
AU  - Cuevas, E.
AU  - Torres, B.
AU  - Barreto, Á.
AU  - García, R.D.
AU  - Cachorro, V.E.
AU  - De Frutos, Á.M.
AU  - López, C.
AU  - Ramos, R.
T1  - A new zenith-looking narrow-band radiometer-based system (ZEN) for dust aerosol optical depth monitoring
LA  - eng
PY  - 2017
SP  - 565
EP  - 579
T2  - Atmospheric Measurement Techniques
SN  - 1867-8548
VL  - 10
IS  - 2
PB  - Copernicus GmbH
AB  - A new zenith-looking narrow-band radiometer based system (ZEN), conceived for dust aerosol optical depth (AOD) monitoring, is presented in this paper. The ZEN system comprises a new radiometer (ZEN-R41) and a methodology for AOD retrieval (ZEN-LUT). ZEN-R41 has been designed to be stand alone and without moving parts, making it a low-cost and robust instrument with low maintenance, appropriate for deployment in remote and unpopulated desert areas. The ZEN-LUT method is based on the comparison of the measured zenith sky radiance (ZSR) with a look-up table (LUT) of computed ZSRs. The LUT is generated with the LibRadtran radiative transfer code. The sensitivity study proved that the ZEN-LUT method is appropriate for inferring AOD from ZSR measurements with an AOD standard uncertainty up to 0.06 for AOD500nm ∼0.5 and up to 0.15 for AOD500nm ∼1.0, considering instrumental errors of 5 %. The validation of the ZEN-LUT technique was performed using data from AErosol RObotic NETwork (AERONET) Cimel Electronique 318 photometers (CE318). A comparison between AOD obtained by applying the ZENLUT method on ZSRs (inferred from CE318 diffuse-sky measurements) and AOD provided by AERONET (derived from CE318 direct-sun measurements) was carried out at three sites characterized by a regular presence of desert mineral dust aerosols: Iza-a and Santa Cruz in the Canary Islands and Tamanrasset in Algeria. The results show a coefficient of determination (R2) ranging from 0.99 to 0.97, and root mean square errors (RMSE) ranging from 0.010 at Izaña to 0.032 at Tamanrasset. The comparison of ZSR values from ZEN-R41 and the CE318 showed absolute relative mean bias (RMB) <10 %. ZEN-R41 AOD values inferred from ZENLUT methodology were compared with AOD provided by AERONET, showing a fairly good agreement in all wavelengths, with mean absolute AOD differences <0.030 and R2 higher than 0.97.
DO  - 10.5194/AMT-10-565-2017
UR  - https://portalciencia.ull.es/documentos/61b4f9e6ff6ada1aa9a07654
DP  - Dialnet - Portal de la Investigación
ER  -