Measuring
There are several different methods to examine the structure of the temperature of the atmosphere:
- A radiosonde attached to a weather balloon is the oldest and most common method used. Each area releases two balloons a day in locations hundreds of kilometres apart.
- Measuring devices attached to commercial airliners permit reporting the isotherm, and its height, to aerial traffic.
- Weather satellites are equipped with sensors which scan the atmosphere and measure the infrared radiation it emits.
- Weather radar detects bright bands, which are radar echoes produced just underneath the isotherm caused by the melting of snow in the layer above 0°C.
- A wind profiler, an upward pointing radar, can detect the speed of precipitation, which is different for rain, snow, and melting snow.
Depending on the frequency and resolution at which these readings are taken, these methods can report the isotherm with greater or lesser precision. Radiosondes, for example, only report a reading twice daily and provide very rough information. Weather radar can detect a variation every five to ten minutes if there is precipitation, and can scan a radius of up to two kilometres.
Read more about this topic: Freezing Level
Famous quotes containing the word measuring:
“By measuring individual human worth, the novelist reveals the full enormity of the State’s crime when it sets out to crush that individuality.”
—Ian McEwan (b. 1938)
“Man always made, and still makes, grotesque blunders in selecting and measuring forces, taken at random from the heap, but he never made a mistake in the value he set on the whole, which he symbolized as unity and worshipped as God. To this day, his attitude towards it has never changed, though science can no longer give to force a name.”
—Henry Brooks Adams (1838–1918)
“We recognize caste in dogs because we rank ourselves by the familiar dog system, a ladderlike social arrangement wherein one individual outranks all others, the next outranks all but the first, and so on down the hierarchy. But the cat system is more like a wheel, with a high-ranking cat at the hub and the others arranged around the rim, all reluctantly acknowledging the superiority of the despot but not necessarily measuring themselves against one another.”
—Elizabeth Marshall Thomas. “Strong and Sensitive Cats,” Atlantic Monthly (July 1994)