Date of Award:


Document Type:


Degree Name:

Master of Science (MS)


Plants, Soils, and Climate

Committee Chair(s)

Inge Dirmhirn


Inge Dirmhirn


Gene Woolridge


Jack Chatelain


This study addresses the availability of total solar irradiance at the earth's surface during varying weather conditions . Two years of irradiance and meteorological data were collected at mountain and valley sites along 40° North latitude in the Rocky Mountains of Utah and Colorado.

Generalized cases of recurring seasonal weather episodes and the associated t o t al irradiance a re identified and discussed , including local mesoscale phenomena (orographic clouds , valley fog, etc.) unique to mountainous regions . The generalized cases can be useful in long- range energy assessment planning. The east and west slopes of the Rocky Mountains are shown to have similar annual average solar energy potential , however the seasonal differences reveal unique climates which require different considerations for each slope.

Short -term relationships between cloudiness and t o t al irradiance are developed for the mountainous region, providing a tool for forecasting solar irradiance using a cloudiness forecast. Total irradiance is shown to correlate much better to opaque sky cover than co total cloud cover . The relationships on the east and west slopes are similar , however greater variations a re observed with elevation between the mountain and valley sites . Short- term forecasting of irradiance is found to be limited due t o unreliable cloudiness fore-casting techniques , tho ugh satellite imagery trajectories are more reliable than numerical methods.



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