EVIDENCE FOR THE PRESENCE OF TURBULENT ATTENUATION ON LOW-ELEVATION ANGLE EARTH-SPACE PATHS .2. FREQUENCY SCALING OF SCINTILLATION INTENSITY ON A 10-DEGREES PATH

This paper presents the results of and conclusions drawn from two expe rimental studies of low-elevation, slant-path scintillation, Part I re lated to 11.2-GHz measurements at an elevation angle of 3.3 degrees, P art II describes 14- and 11-GHz observations made on a (nominal) 10 de grees path over a four year period, The resulting time-series data hav e enabled frequency scaling to be investigated in some depth, Scintill ation occurring during periods unassociated with fading is found to be well modeled in its frequency scaling behavior by classical theories of clear air turbulence (CAT), This is not the case, however, for scin tillation that occurs during, just before, or just after rain-induced fading, A rapidly fluctuating attenuation mechanism, not separable fro m CAT-induced scintillation on the basis of its spectrum alone, is tho ught to be responsible for this anomalous frequency-scaling result.