Physical significance of theE_sparameters ƒ_bE_s, ƒE_s, and ƒ_oE_s: 2. Causes of partial reflections fromE_s

Abstract

Adoption of the light-limitation method for preventing reservoir eutrophication requires an efficient destratification system. Here, bubble plume system was discussed. The stratification is destroyed with the evolution of the intermediate layer, which is bounded from the upper and the lower layers by fronts. Most efficient destratification is achieved with the equivalent plume number of 1300. The upper front density gap is parameterized with the bubbling rate, the depth and intensity of the initial ther-mocline. For the light limitation method, the bubbling rate should be large enough to make it small. For the hypolimnetic aeration, on the other hand, the bubbling is to be weak as to keep it large.

Simultaneous VHF radar backscatter and ionosonde observations of low-latitude E region

“…Similar results have also been seen at Chung-Li (Lee et al, 2000). Reddy (1968) showed that partial reflections from sharp electron density gradients or scattering from small-scale irregularities in E s can produce partially reflected E s echoes of sufficient intensity over large frequency ranges above f b E s . Experimental evidence on this aspect can be found in Ogawa et al (1998), in which they detected 2-5 MHz signals but not 6 and 7 MHz in their FM-CW sounder observations.…”

Seasonal variation of low-latitude E-region plasma irregularities studied using Gadanki radar and ionosonde

“…The frequencies observed between f b E s and f t E s were interpreted as due to scattering from the irregularities (e.g. Reddy, 1968). Recent studies on the interpretation of mid-latitude E s (Hussey et al, 1998;Ogawa et al, 2002;Maruyama et al, 2006), however, suggest that f o E s (f t E s -half of the gyro-frequency (=0.61 MHz)) corresponds to either local maximum electron density in a non-uniform layer or peak electron density in a spatially uniform layer and f b E s (which is the minimum frequency of the F layer trace) corresponds to the minimum value among the peak electron densities in a layer, that does not allow the frequencies <f b E s to propagate upward.…”

Effects of scattering on the partial transparency of sporadic-E layers: Part I. (Neglecting the earth's magnetic field).

“…The scattering model was examined by REDDY (1968) about 20 years ago, but the present work is differs from his in the following two points. The main difference is that Reddy supposed the scatterers of radio waves were "random" or "turbulent" irregularities, whereas we propose in this paper that the scatterers are weak "wavelike" fluctuations of electron density in the sporadic -E layer .…”

“…10(a). Taking into account the facts that the layer-widths of most sporadic-E layers are between 1 and 3km (SMITH and MECHTLY, 1966;MILLER and SMITH, 1978), and that the partially transparent Es traces over several MHz are often observed on sonograms (REDDY, 1968;REDDY and MUKUNDA RA0,1968), it is concluded from Figs. 4(b) and 6(b) that the thin layer model of reasonable layer thickness but without irregularities is not appropriate as a sporadic-E layer model which can explain the partial transparency characteristics observed.…”

“…The attenuation was increased until the trace disappeared from the ionogram, and they found that a layer at sporadic-E altitude with a reflection coefficient greater than 10-3 would be recorded on the ionogram. REDDY (1968) used the values of 10-3 and 10-2 as the threshold reflection coefficient, which is referred to as |R|min in the following. In calculating theoretical sonograms, the following two values are used as the threshold reflection coefficient:…”