sun and aureole measurements a sensor for cloud optical properties and circumsolar radiation
DESCRIPTION
10. Lab calibration - NIST traceable (see Visidyne Cal Brochure VI-5487) Radiometric accuracy: Disk radianceTRANSCRIPT
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Contacts
A.T. Stair 781-272-1220
John DeVore 781-791-3209
Example Web Display (Daily) www.visidyne.com/sam/sam_data.htm
11. Field Calibration/Verification
• Absolute radiometric calibration of solar disk camera; verified with thousands of measurements made next to AERONET• Consistent aureole pixel-to-pixel response, e.g. “gradient” correction; verified with hundreds of measurements of uniform clouds• Stable for long periods
~ 24 months at NASA GSFC (MD)
~ 12 months at DOE/ARM CRF (OK)
9. SAM 300 Series Sensors•Dome versions (very robust) have produced data daily at the Goddard Space Flight Center (MD) and at the DOE/ARM CRF (OK) under a NASA grant and with DOE/ARM support
10. Lab calibration - NIST traceable (see Visidyne Cal Brochure VI-5487)
• Radiometric accuracy: Disk radiance <1% for OD <0.6, 3% for OD 2 (DNI ~ 250 w/m2) Aureole radiance ~5% - 15%
• Aureole profile precision: Pixel-to-Pixel Std Dev ~0.5%
• For ODs <~2 there is a data gap of ~ 0.1o (~0.3 to 0.4+ degrees) due to the aureolegraph design, typically
<1% error in CSR
Upper: SAM OD & AERONETMiddle: Disk & Aureole Radiance, Integrate for CSRLower: Derived particle size distribution (see J. Atmos. Ocean. Tech., 26, pg 2531)
VI-5493a April, 2012
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DOE ARM SGP
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1.Weatherized SAM 400 Series
8. DNI From SAM Data 1) Use measurements: Spectral irradiance (item 6) H2O, O3 & aerosols (item 7)
2) Convert to broadband irradiance
Use radiative transport model,or
regression analysis from DNI
3) Integrate over wavelength
7. SAM Spectrometer Data
6. Direct Normal Irradiance
2. Data Example (OD ~2)
3. SAM is a patented, calibrated, integrated sensor suite with dedicated software:
• Precision solar tracker• Solar disk camera• Aureolegraph imager• Spectrometer-vis/nir (optional)
• Halo camera (optional) 4. Capabilities - 5 Years in Development and Applications
• Uses a narrow-band filter at 670 +/-5 nm (changeable) and measures:--Solar disk radiance (OD)Solar disk radiance (OD)
ODs from 0.01 to 10--Aureole (circumsolar Aureole (circumsolar radiation)radiation)
from near edge of solar disk to 8o
from center (see item 10)--Atmospheric constituentsAtmospheric constituents (see item 7)--Aureole (halos)-vertical to Aureole (halos)-vertical to 50º50º
5. Papers and Posters•Particle size distributions: ~5 to ~65 m (400 Series); see DeVore,
et al., “Retrieving Properties of Thin Clouds From Solar Aureole Measurements”, JAOT, 26, pgs 2531
- 2548.•Posters from science meetings and all papers are available at: www.visidyne.com/SAM/Papers.htm
Sensor (20 x 60 cm);Control console not shown (30 x 48 x 74 cm)
OzoneAerosols
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