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The scale of dBZ values can be seen along the bottom of the image. dBZ is a logarithmic dimensionless technical unit used in radar. It is mostly used in weather radar, to compare the equivalent reflectivity factor (Z) of a remote object (in mm 6 per m 3) to the return of a droplet of rain with a diameter of 1 mm (1 mm 6 per m 3). [1]
Light rays enter a raindrop from one direction (typically a straight line from the Sun), reflect off the back of the raindrop, and fan out as they leave the raindrop. The light leaving the raindrop is spread over a wide angle, with a maximum intensity at 40.89–42°.
The daily light integral (DLI) is the number of photosynthetically active photons (photons in the PAR range) accumulated in a square meter over the course of a day. It is a function of photosynthetic light intensity and duration (day length) and is usually expressed as moles of light (mol photons) per square meter (m −2) per day (d −1), or: mol·m −2 ·d −1.
Atmospheric refraction of the light from a star is zero in the zenith, less than 1′ (one arc-minute) at 45° apparent altitude, and still only 5.3′ at 10° altitude; it quickly increases as altitude decreases, reaching 9.9′ at 5° altitude, 18.4′ at 2° altitude, and 35.4′ at the horizon; [4] all values are for 10 °C and 1013.25 hPa ...
Juan Baigorri Velar and his rain-making machine. (1938) Juan Pedro Baigorri Velar (1891 in Concepción del Uruguay – 24 March 1972 in Buenos Aires ) was an Argentine engineer; known for his claims that he had invented a rain-making machine.
Since the 1940s, cloud seeding has been used to change the structure of clouds by dispersing substances into the air, potentially increasing or altering rainfall. [2] In spite of experiments dating back to at least the start of the 20th century, however, there is much controversy surrounding the efficacy of cloud seeding, and evidence that cloud seeding leads to increased precipitation on the ...
Most modern rain gauges generally measure the precipitation in millimetres in height collected during a certain period, equivalent to litres per square metre. Previously rain was recorded as inches or points, where one point is equal to 0.254 mm or 0.01 of an inch. [16] Rain gauge amounts are read either manually or by automatic weather station ...
The first measurements of this distribution were made by rather rudimentary tool by Palmer, Marshall's student, exposing a cardboard covered with flour to the rain for a short time. The mark left by each drop being proportional to its diameter, he could determine the distribution by counting the number of marks corresponding to each droplet size.