Station Observation Definition
The list of observed elements is maintained for each station registered in the Clidata system. The observation period and the instrument are defined for each of these elements.
For the purpose of documentation, and to determine archive completeness, the Clidata system introduced the definition of the observation scheme. For each of the observed elements the observation scheme must be defined. The observation scheme specifies the times during a day in which the observation is carried out.
The Clidata system distinguishes between two types of the observation schemes: regular and non-regular (climatological). The regular scheme is used mostly for the observations of automatic stations (e.g. each 15 minutes) and the non-regular scheme is mostly for manual stations (human observations, e.g. at 07, 14 and 21 or just once a day).
For each of the observed elements the historical unit can be defined. This historical unit can be later used for automatic transfer of the values from historical to current ones.
In addition, there are definitions for the automatic calculation of hourly and daily aggregated values.
The hourly calculated values are stored and calculated for a specific time during the day. The hourly calculated values can be, for example, calculated relative humidity from temperature, pressure and wind speed at different times (e.g. 07, 14 or 21).
The daily aggregated values are functions like daily minimum, maximum, sum or average per day.
Following definition of the calculations, they are performed automatically by the Clidata system without any user action necessary.