9123150 Kundu This project will determine the frequency of maximum correlation of the solar microwave flux with the total solar irradiance, and to obtain statistical evidence regarding the sources of the correlation. The goals are to overcome some of the failure of the 2800 MHz microwave flux to provide adequate proxy data for irradiance measurements, and to use the additional information in multi-frequency data to reveal the physical reasons for the presence or absence of certain correlations. Using the solar flux data at 1000, 2000, 3750 and 9400 MHz from Toyokawa Observatory, along with the 2800 MHz flux data from Ottawa, the PI will correlate the microwave observations with irradiance measurements obtained by The Active Cavity Radiometer Irradiance Monitor (ACRIM) aboard the Solar Maximum Mission (SMM). The project will model the microwave flux spectrum in the 1000-9400 MHz range in order to extract its principal (sunspot, coronal and chromospheric) components. Using the known associations of these spectral components with optical observations, the PI will obtain their relative normalizations so that the components may be identified from the microwave measurements alone. Finally, the PI will obtain the optimum functional relationships by which the microwave flux spectrum can be used as a proxy for solar irradiance. ***
