Labels:book | bulletin board | crt screen | monitor | person | poster | reckoner | sky | windowpane OCR: MINIMUF MODEL DEVELOPMENT THEORETICAL BACKGROUND A central task of long- term statistical hf propaga tion forecasting is the prediction of maximum usable frequency (MUF. The MUF in turn, is principally controlled by the critical frequency of the F2 layer of the ionosphere F and it is the success in predicting this quantity that primarily determines the accuracy of the MUF forecast Unlike the and Fi layers, which can be modeled quite well as function of a single parameter- cos (the cosine of the instantaneous solar zenith angle) proportional to the solar intensity the physics of the layer 15 generally believed to involve an interaction of pho tochemi ical and trans port processes sufficiently complex that diurnal seasonal and geographical f.F2 variations cannot be simply accommodated throug ...
