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McComiskey, A, Ricchiazzi P, Gautier C, Lubin D.  2006.  Assessment of a three dimensional model for atmospheric radiative transfer over heterogeneous land cover. Geophysical Research Letters. 33   10.1029/2005gl025356   AbstractWebsite

A three-dimensional (3D) atmospheric radiative transfer model that explicitly represents surface albedo heterogeneity is tested against a one-dimensional model and surface irradiance observations in a polar region where land cover heterogeneity is high. For observations located near high latitude coastlines, the contrast between the highly absorbing ocean and reflective snow surface creates spatial heterogeneity, or a 3D effect, around the observation site. The resulting effect on radiation at the sensor should be taken into account when using a solar radiative transfer model to interpret measurements. This assessment shows that better closure is obtained with a three-dimensional model (<= 5%) versus a plane-parallel model (<= 7%). The importance of the surface 3D effect increases with aerosol or cloud optical depth and with surface albedo contrast. The model used here can be implemented at any surface site given the surrounding land cover properties.

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Ricchiazzi, P, Gautier C, Lubin D.  1995.  Cloud Scattering Optical Depth and Local Surface Albedo in the Antarctic - Simultaneous Retrieval Using Ground-Based Radiometry. Journal of Geophysical Research-Atmospheres. 100:21091-21104.   10.1029/95jd01461   AbstractWebsite

We have used solar irradiance measurements from a ground-based multichannel radiometer system deployed at Palmer Station, Antarctica (64 degrees 46'S, 64 degrees 04'W), during spring 1991 to simultaneously estimate cloud scattering optical depth and surface albedo. Irradiance measurements at 410 and 630 nm, in conjunction with a discrete ordinate radiative transfer (RT) model, enable this simultaneous retrieval by exploiting the wavelength dependence in Rayleigh scattering strength. The RT model is used in an inverse mode to find the values of surface albedo and cloud optical depth that match calculated and measured irradiances at both wavelengths. Under the homogeneous stratiform cloud cover for which the technique applies, surface albedo at 630 nm was consistently retrieved at above 0.9. For most homogeneous, overcast conditions, cloud optical depth (at 630 nm) is found to be in the range 20-50, with a most probable value of 25. This measurement and retrieval technique should be useful for compiling high-latitude cloud opacity and surface albedo climatologies of interest for global change and photobiology research.

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Lubin, D, Vogelmann AM.  2010.  Observational quantification of a total aerosol indirect effect in the Arctic. Tellus Series B-Chemical and Physical Meteorology. 62:181-189.   10.1111/j.1600-0889.2010.00460.x   AbstractWebsite

We use 6 yr of multisensor radiometric data (1998-2003) from the U.S. Department of Energy Atmospheric Radiation Measurement (ARM) program to provide an observational quantification of the short-wave aerosol first indirect effect in the Arctic. Combined with the previously determined long-wave indirect effect, the total (short-wave and long-wave) first indirect effect in the high Arctic is found to yield a transition from surface warming of +3 W m(-2) during March to a cooling of -11 W m(-2) during May, therefore altering the seasonal cycle of energy input to the Arctic Earth atmosphere system. These data also reveal evidence of a first indirect effect that affects optically thinner clouds during summer. which may represent an additional negative climate feedback that responds to a warming Arctic Ocean with retreating sea ice.