SE.ACMF Meteorological observations — Significant clouds, hourly values

Purpose: Describes current weather and over time the climate. Basis for forecast verification. Unit:Amount of clouds in eighths, cloud base in meters. Characteristics:Cloud base and amount are reported at one hour intervals from a number of official stations equipped with cloud altimeters. Cloud amount and cloud base are determined by an advanced algorithm in the measuring instrument. Most measuring stations send automatically produced reports. All cloud layers detected by the instrument are reported, with a maximum of 4 cloud layers. For manual stations, the following clouds are reported: The lowest cloud layer, irrespective of its amount of cloud, reported at least 1/8; Next higher cloud layer covering a total of 3/8 or more of the sky. Next higher cloud layer covering a total of 5/8 or more of the sky. Cumulonimbus clouds not reported under points 1, 2 or 3 are always reported in a specific group regardless of the amount of cloud. Today’s measuring instruments cannot distinguish such clouds. Cloud base for each cloud layer is reported. Ex:1/8 on 300 m, 3/8 on 500 m and 5/8 on 1 000 m. Cloud amount is reported from 0/8 (cloud-free) to 8/8 (mulet).9/8 means that the cloud sky cannot be observed due to fog or high snowlines. In 9/8 the term vertical visibility is used, which indicates how far vertical it is possible to see. Amount of clouds Data is available with a value of 0 to 9. Value 10 to 15 are empty; reserved for aerodrome observations not included in this dataset. Value 0 to 8 means 0 to 8 eighths, 9/8 refers to vertical visibility. Parameter 29 Minimum cloud layer instantaneous value 1 time per hour Amount of clouds, lowest available clouds, regardless of the amount of clouds. Parameter 31 Other cloud layer instantaneous value 1 time per hour Cloud quantity, next higher (other) cloud layer. Parameter 33 Third cloud layer instantaneous value 1 time per hour Cloud quantity, next higher (third) cloud layer. Parameter 35 Fourth cloud layer instantaneous value 1 time per hour Cloud quantity, next higher (fourth) cloud layer. Cloud base Cloud base refers to the vertical distance from the ground to the underside of the clouds. Parameter 28 Cloud base, lowest cloud layer instantaneous value, 1 hour Cloud base, lowest cloud layer regardless of the amount of clouds. The amount of these clouds can be found under parameter 29. Parameter 30 Cloud base, second cloud layer instantaneous, 1 hour Cloud base, next higher (other) cloud layer.The amount of these clouds can be found under parameter 31. Parameter 32 Cloud base, third cloud layer instantaneous, 1 time per hour Cloud base, next higher (third) cloud layer.The amount of these clouds can be found under parameter 33. Parameter 35 Cloud base, fourth cloud layer instantaneous, 1 hour Cloud base, next higher (fourth) cloud layer. The amount of these clouds can be found under parameter 34. The cloud base of cumulonimbus clouds (CB) not reported in other cloud layers. CB cannot be discernible by automatic instruments, these data are mainly found in historical observations that were manual. Design: Date, time, value and quality. Quality codes:Green values (G) mean approved quality. Yellow values (Y) means data that may be suspiciously inaccurate. It can also be an aggregated value based on other metrics. Limits: 0 to 7 500 m (cloud base), 0 to 9 (amount of clouds) For more info see: https://www.smhi.se/kunskapsbanken/molnighet-och-molnmangd-1.1514 Delivery: Data is delivered in two different ways. 1. Via a user interface where measurement series can be downloaded for one station at a time. Data can be downloaded for the last 24 hours, the last four months or the full time series except for the last three full months (historical reviewed). 2. Via a machine-machine solution (Atom flow rate). There, the same measurement series as above can be obtained as well as real-time data. These are the last hour’s readings. They can be retrieved for one measuring station at a time or for all active measuring stations.