Artigo de peri??dico
Different strategies to retrieve aerosol properties at night-time with the GRASP algorithm
Registro en:
1680-7316
22
19
10.5194/acp-19-14149-2019
88.732
96.00
Autor
BENAVENT-OLTRA, JOSE A.
ROMAN, ROBERTO
CASQUERO-VERA, JUAN A.
PEREZ-RAMIREZ, DANIEL
LYAMANI, HASSAN
ORTIZ-AMEZCUA, PABLO
BEDOYA-VELASQUEZ, ANDRES E.
MOREIRA, GREGORI de A.
BARRETO, AFRICA
LOPATIN, ANTON
FUERTES, DAVID
HERRERA, MILAGROS
TORRES, BENJAMIN
DUBOVIK, OLEG
GUERRERO-RASCADO, JUAN L.
GOLOUB, PHILIPPE
OLMO-REYES, FRANCISCO J.
ALADOS-ARBOLEDAS, LUCAS
Resumen
This study evaluates the potential of the GRASP
algorithm (Generalized Retrieval of Aerosol and Surface
Properties) to retrieve continuous day-to-night aerosol properties,
both column-integrated and vertically resolved. The
study is focused on the evaluation of GRASP retrievals
during an intense Saharan dust event that occurred during
the Sierra Nevada Lidar aerOsol Profiling Experiment I
(SLOPE I) field campaign. For daytime aerosol retrievals,
we combined the measurements of the ground-based lidar
from EARLINET (European Aerosol Research Lidar
Network) station and sun???sky photometer from AERONET
(Aerosol Robotic Network), both instruments co-located in
Granada (Spain). However, for night-time retrievals three
different combinations of active and passive remote-sensing
measurements are proposed. The first scheme (N0) uses lidar
night-time measurements in combination with the interpolation
of sun???sky daytime measurements. The other two
schemes combine lidar night-time measurements with nighttime
aerosol optical depth obtained by lunar photometry either
using intensive properties of the aerosol retrieved during
sun???sky daytime measurements (N1) or using the Moon aureole
radiance obtained by sky camera images (N2). Evaluations of the columnar aerosol properties retrieved
by GRASP are done versus standard AERONET retrievals.
The coherence of day-to-night evolutions of the different
aerosol properties retrieved by GRASP is also studied. The
extinction coefficient vertical profiles retrieved by GRASP
are compared with the profiles calculated by the Raman
technique at night-time with differences below 30% for all
schemes at 355, 532 and 1064 nm. Finally, the volume concentration
and scattering coefficient retrieved by GRASP at
2500ma.s.l. are evaluated by in situ measurements at this
height at Sierra Nevada Station. The differences between
GRASP and in situ measurements are similar for the different
schemes, with differences below 30% for both volume
concentration and scattering coefficient. In general, for the
scattering coefficient, the GRASP N0 and N1 show better results
than the GRASP N2 schemes, while for volume concentration,
GRASP N2 shows the lowest differences against
in situ measurements (around 10 %) for high aerosol optical
depth values.