Presentation on theme: "SW o SOLAR LW o OLR. SW response T response ScaRaB = SW and LW broadband radiometer measuring the whole spectral ranges of the solar reflected radiation."— Presentation transcript:
SW o SOLAR LW o OLR
SW response T response ScaRaB = SW and LW broadband radiometer measuring the whole spectral ranges of the solar reflected radiation (SW), and of the longwave (LW) emission from the surface and atmosphere.
OLR History First measurements of OLR as early as 1959 from Explorer-7 Experiments - ERB, ERBE, ScaRaB, CERES, GERB First routine measurements of OLR from operational satellites began in 1974 –NOAA scanning radiometer ( SR)- window channel ( microns) –Linear algorithm between window radiances and total OLR – based on radiative calculations with model atmospheres –Evolved a few years later to a non linear algorithm which is still in use today - adjusted for different spectral interval SR data , AVHRR 1979-onward
Calibrazione (intercalibrazione) Sampling diurno Calcolo del flusso a partire della radianza (identificazione della scena)
Radiance-to-flux conversion Radiance TOA flux estimate SAT
Angular Dependence Model (ADM) Flux with where is the ADM for the j scene
Clear-Sky Ocean CERES ADM Polar plots for the SW clear-sky ADMs at the 0°-25° SZA bin. Radii represent the VZAs and polar angles represent the AZMs. Sun is located at the 180° AZM. Low wind (0-3 m/s) High wind (9-12 m/s)
Equator Crossing Times for NOAA Polar Orbiters
OLR: Outgoing LW Radiation
Multi-spectral HIRS OLR Algorithm a i =regression coefficients =local zenith angle Ellingson et al. (1989)
HIS OLR Regression Model Channels and spectral intervals – stepwise regression based on 1600 Phillips soundings and radiation transfer model HIRS ChannelWavelength (μm)Atmos Sensitivity H Near Sfc temp H107.8 – 8.5Lower trop water vapor H Upper trop water vapor H Air temp- at 100mb
OLR + Long consistent time series + 4 times/day -Assumptions on remaining part of the LW spectrum -No equivalent product for SW
Clear-sky OLR Anomaly (Jan 1998) AVHRR OLR lacks sensitivity to water vapor variation, especially the upper tropo. humidity (UTH).
Fo cosθ Sfc obs Sat obs
LIDAR CLOUD RADAR PREC. RADARSURF. RADAR
SAR Dipole eddies in Sarichef Strait, which separates Hall and St. Matthew islands, Bering Sea, Alaska, were captured by the ERS-1 satellite in February The individual eddies have diameters of 5 to 9 km with tails of 12 to 19 km. The eddies were tidally generated, and the tidal amplitude was high at the time of the imaging. The eddies were observed only when frazil and grease ice acted as tracers.