240 likes | 330 Views
AEROSOL ARCTIC CAMPAIGN AT ALOMAR IN JUNE-JULY 2002. V.E. Cachorro, C. Toledano, R. Vergaz, M. Sorribas and A.M. de Frutos Grupo de Optica Atmosférica Universidad de Valladolid Spain. Objective Description of the Instrumentation Methology
E N D
V.E. Cachorro, C. Toledano, R. Vergaz, M. Sorribas and A.M. de Frutos Grupo de Optica Atmosférica Universidad de Valladolid Spain
Objective • Description of the Instrumentation • Methology • Measurements of AOD and alpha Angström parameter • Temporal analysis of aerosol parameters: AOD and alpha • Addional data: Backtrayectories, weather maps... • Conclusions OVERVIEW
OBJECTIVE Determination and evolution of aerosol parameters • AOD values (440, 670,80,1020) • Angström parameters: VIS-NIR;pair • ------------- • Microphysical Parameter: effective radius, volume, mass, • Radiative parameters: wo, g, Phase Function
INSTRUMENTATION Brewer of ALOMAR
1020 opaco 870 p. 870 p. 670 940 440 870 870 p. Panel solar 10 nm ancho Sun-photometer Cimel 318A (#243) PHOTONS-AERONET Zenith motor Collimator Sensor head DCP antenna Azimuth motor Solar panel Electronics
METHODOLOGY Determination of the aerosol optical depth
Cimel data Extintion measurements Sky Radiance (Almucantar, PP) Polarization (870 nm) Aerosol optical depth (AOD) • Particle size distribution • Microphysical Parameters • Optical parameters Ångström Parameter Aerosol Cimel Filter (nm.) 440 670 870 1020 870P
Cimel Data Standard AERONET data processing for Aerosol Optical depth (AOD) Pre calibration coefficients, Vo () (intercalibration) Rough measurements Level 1.0 Cloud Screening AERONET Measurements without clouds Level 1.5 Post Calibration coefficients, Level 2.0 (Quality Assured) Final measurements (interpolation)
AEROSOL CIMEL MEASUREMENTS May 26th and July 24th 2002
AEROSOL CIMEL MEASUREMENTS May 26th and July 24th 2002
AEROSOL CIMEL MEASUREMENTS Spectral analysis alpha parameter
AEROSOL CIMEL MEASUREMENTS May 26th and July 24th 2002
AEROSOL CIMEL MEASUREMENTS May 26th and July 24th 2002, GENERAL STATISTIC
AEROSOL CIMEL MEASUREMENTS Medium turbidity values: AOD=0.14, alpha =2.04, However, very thin cirrus cloud are present
AEROSOL CIMEL MEASUREMENTS Low turbidity event: AOD=0.06 alpha=1.4
AEROSOL CIMEL MEASUREMENTS High turbidity event: AOD=0.26 alpha=1.9 Very good days to study cirrus cloud with LIDAR
EPP spectrograph (StellarNet) Calibration and measurements Eight Channels • Spectral Range (190-790) nm. • In the field (300-600) • Dinamic range 65000 counts. • - Spectral Resolution 2 nm [Sorribas M., 2001]. • - Error in wavelength 0.25 nm • Detector: CCD Hamamatsu de 64 * 1024 pixeles. • - Entrance slit widh 25 m. • - • Stray Light < 0.2% a 220 nm.
EPP spectrograph (StellarNet) Calibration and measurements Global Component Channel
EPP spectrograph Calibration and measurements Direct Component Channel Comparison with the Langley method
CONCLUSIONS • A varying AOD evolution is observed • The AOD values gives a median-low turbidity, about 0.13 at 440 nm, but higher than expected • alpha parameter > 1 indicate not clear marine type, with abundant fine particles, thus coastal marine type is mixed with polluted and continental aerosol types • Size distribution particle and radiative parameter are in process. Measurement of Sky radiance needs to be added • Comparative data of EPP with Bentham are in agreement • Comparative AOD between EPP, Cimel, and Brewer are in process