Oxford's Contribution to the Global Radiation Budget through Surface Albedo

I. Introduction

Climate stability is a function of the amount of radiant energy input to the Earth system, the distribution of input, and the fraction that is output back into space. The radiant energy reaching any point on Earth's surface (input) is controlled by the combination of shape, orbital state, and atmospheric characteristics of Earth at any point in time. Radiant energy is absorbed, reflected, or scattered by the interactions with Earth's matter. The initial interaction with matter is responsible for the pathway of distribution and Earth's global radiation budget. The input and distribution of radiant energy dictate, to a degree, other variables including temperature, atmospheric circulation, ocean circulation, precipitation, biological activity, etc. (important). A quantifiable component of distribution is surface albedo, defined as the proportion of incident energy reflected from a surface. The proposed research will measure surface albedo at varied spatial and temporal scales to determine the affect of surface type on the regional/global radiation budget. Specifically this research will address the methods of measurement and the contribution of the Oxford area modeled on different spatial and temporal scales.

II. Previous Work
The Earth's radiation budget is a complex conglomeration of photon-matter interactions that for simplicities sake are modeled/ measured /estimated at low resolutions (averaged) both spatially and temporally.

Measurements Defined
Solar Constant/ fluxes in Solar output
Earth orbit- variations in mean distance
Revolution /Precession
Geographic component /latitude
Atmosphere contribution
Surface Albedo

Techniques to measure
Pre-satellite measurements
Eyes in the sky
Number of Eyes
Acuteness of vision
When and Where the eyes are open
BRDF bidirectional reflectance distribution function

III. Methods
This research will use multiple data sets at varied spatial and temporal scales to estimate and characterize surface albedo.

1. Fine scale measurements of surface albedo around the Oxford area will be collected using Hobo light intensity meters. These data will be calibrated against a suite of instruments including a precision spectral pyronometer, and digital instruments that located at the Ecological Research Center, north of Oxford and a weather station on the roof of Boyd Hall. The initial calibration phase will be followed by repeat sampling of 5-10 transects at the same sampling sites under different atmospheric conditions and periods of day.

2. The Enhanced Thematic Mapper instrument onboard the Landsat 7 satellite will be calibrated against the insitu data, and analaysised with a Biodirectional Refectance Distribution Function (BRFD), to calculate a absolute value for surface albedo. These data (P20-R33) are 30m resolution and cover northern Kentucky, southeast Ohio, and southern Indiana. Radiance values will be calculated for data collected on July 15, Aug 16, Sept 17, and Dec 22 1999 and used for a semi-quantitative area based evaluation of surface change through one period of the vegetative cycle. These analysis will include a superivised classification, and a correction for topography. These data will be provided by John Millard via the OhioView Project.

3. A selection of surfaces sampled insitu will be monitored for the effect of reflected radiation on temperature of the local atmosphere.

IV. Results
V. Conclusions

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