1.3 Automated weather observation
The collection of most routine meteorological data is something that can be easily automated using electronic instrumentation. Making electronic measurements of temperature is easy - the electrical properties of some materials are very temperature sensitive, as are the tiny, but easily measurable, electrical voltages generated when two different metals are brought into contact. In fact, there are a large number of other 'thermo-electric' effects and experimental scientists will tell you that when the first prototypes for most electronic measuring instruments are built in the laboratory they often respond to changes in temperature more markedly than to changes in the quantity that they were designed to measure. There is an almost equally rich variety of 'piezoelectric' effects (i.e. effects in which changes in pressure generate changes in electric properties) that can be engineered into electronic barometers. Humidity too can nowadays be monitored in the changing properties of simple electronic components. In fact, all of the above instrumentation can be comfortably fitted into a modern digital wristwatch.
An automated weather monitoring station is essentially a set of electronic sensors linked to a telecommunications channel that need be little more than a mobile phone or a wireless radio link. You may well have seen roadside weather monitoring stations similar to that shown in Figure 2. Routine reports from roadside and, at airports, runwayside, automatic weather stations are important for issuing travel safety alerts.
Several basic weather observations are difficult to automate, though not impossible. However, the smarter the electronic instrument, the more expensive it is likely to be. Suggest two kinds of observation that a person can do with relative ease compared with an electronic system.
You may have thought of things like visibility, cloud cover and, in particular, cloud type. These can all be recorded by trained observers without any instrumentation beyond the human eye, so the electronic world starts at a disadvantage. (A simple, well-placed, live, video camera, though useful, still needs an observer and places higher demands on data transmission.)