A Differential Thermistor Thermometer for measuring Temperature Gradients in the Vicinity of the Ground

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Johnstone D. R.
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The meteorological factors which have to be taken into account in predicting the fate of insecticide spray droplets include wind speed, temperature and (for aqueus droplets) moisture content of the air; also atmospheric stability or turbulence. The latter is of particular importance in the tropics where intense convection can follow rapid heating of the surface layers as the sun ascends to its zenith. Standard meteorological equipment for measuring the first three factors is normally universally available, but instability, displayed primarily as small-scale turbulence under conditions of super adiabatic lapse rate, which can affect the diffusion and transport of very small droplets, is less readily measured. Turbulence may be related either to the frequency and magnitude of small-scale wind fluctuations (J. I. P. Jones, private comm,), or to temperature fluctuations and gradient in the vicinity of the ground (Yeo, Akesson and Coutts, 1959). Geiger (1966) cites the following gradients as approximating to the stated conditions between altitudes of 25 and 100 m.
East African Agricultural And Forestry Journal, XXXV (No. 4), p. 300-307