Weather File

Registered by r.roeterdink on 2017-02-07

Introduction of weather variations defined by a weather file.

This blueprint proposes to introduce the option to vary the weather during the day using definitions in a special file.

Presently, one can select the season and the type of weather, but the selected weather will then last throughout the session, without any change.
This blueprint proposes to allow the use of a file, known as the weather file, to set different weather patterns to occur during the day.
The weather file will allow the setting of many aspects of the weather, and different types of weather can be defined to start at a specific time.

The following definitions are available :

clear - clear weather, with possible overcast sky.
Available options :
 * overcast : percentage of cloud cover
 * overcastvariation : max allowed change of cloud cover from the value defined in overcast
 * overcastrateofchange : rate of change of percentage of cloud cover,
the cloud cover will change within the bracket as defined by overcastvariation
 * visibility : maximum visibility

precipitation (rain or snow) - one or more periods of precipitation, which can be eiter rain or snow.
Available options :
 * density : the density of the precipitation
 * variation : allowed variation in density
 * rateofchange : the rate of change of variation in density
 * probability : the probabiltity that there will actually be precepitation at any given moment
 * spread : indication of no. of separate periods in which there actually will be precipitation
The combination of probability and spread determine the type of precipitation, varying from a single continuous period to a series of short showers.
 * visibilityatmindensity : visibility at minimum density
 * visibilityatmaxdensity : visibility at maximum density
The rate of change required for visibility is derived from the rateofchange for the precipitation itself.
 * overcaststart : the required cloud cover before the precipation will start
This will also be set as the cloud cover during the precipitation spells.
 * overcastbuildup : the rate of change of cloud cover during cloud cover build up up to the value as set for overcaststart, starting at the present overcast rate
 * overcastdispersion : the rate of change of cloud cover after the precipitation has ended, reducing the cloud cover to the value as defined in overcast.
 * overcast : percentage of cloud cover during dry spells
 * overcastvariation : max allowed change of cloud cover from the value defined in overcast
 * overcastrateofchange : rate of change of percentage of cloud cover,
the cloud cover will change within the bracket as defined by overcastvariation
 * overcastvisibility : visibility during dry spells

fog - period of fog
Available options :
 * visibility : visibility when fog is fully set
 * fogsetrate : rate of decline in visibility when fog is setting in
 * fogliftrate : rate of increase in visibility when fog is lifting

Multiple sets of fog variables, each with their own timestamp, can be set to allow for variation in fog densisty.

The weather file is a STF-formatted file, this format is chosen because processing is readily available and users are very familiar with this type of file.
The file(s) can be located anywhere; a user selection to select the required weather file will be included in the main menu.

An example of a weather file is shown below. This defines for setting in just after midnight until mid morning, followed by a short clear spell with a series of showers during the afternoon and a fine clear evening with clouds gradually decreasing.

SIMISA@@@@@@@@@@JINX0G0t______
WeatherSettings ( 6
       WeatherSetting ( "Clear"
              StartTime ( 00:00 )
              Overcast ( 20 )
              OvercastVariation ( 10 )
              OvercastRateOfChange ( 0.1 )
                      )
       WeatherSetting ( "Fog"
              StartTime ( 01:00 )
              Visibility ( 300 )
              FogSetRate ( 600 )
              FogLiftRate ( 1800 )
                      )
       WeatherSetting ( "Clear"
              StartTime ( 10:00 )
              Overcast ( 20 )
              OvercastVariation ( 10 )
              OvercastRateOfChange ( 0.1 )
                      )
       WeatherSetting ( "Rain"
              StartTime ( 11:30 )
              Density ( 0.9 )
              Variation ( 0.2 )
              RateOfChange ( 0.05 )
              Probability ( 60 )
              Spread ( 7 )
              Overcast ( 50 )
              OvercastRateOfChange ( 0.01 )
              OvercastStart ( 80 )
              OvercastBuildUp ( 0.5 )
              OvercastDispersion ( 0.8 )
              VisibilityAtMinDensity ( 1000 )
              VisibilityAtMaxDensity ( 400 )
              OvercastVisibility ( 4000 )
                      )
       WeatherSetting ( "Clear"
              StartTime ( 15:00 )
              Overcast ( 35 )
              OvercastVariation ( 10 )
              OvercastRateOfChange ( 0.1 )
              Visibility ( 10000 )
                      )
       WeatherSetting ( "Clear"
              StartTime ( 19:00 )
              Overcast ( 20 )
              OvercastVariation ( 20 )
              OvercastRateOfChange ( 0.1 )
              Visibility ( 10000 )
                      )
                  )

Discussion: http://www.elvastower.com/forums/index.php?/topic/29990-proposal-for-variable-weather-definition-using-weather-file/
Roadmap: https://trello.com/c/9iufnscP/381-weather-file

Blueprint information

Status:
Started
Approver:
James Ross
Priority:
Medium
Drafter:
r.roeterdink
Direction:
Approved
Assignee:
James Ross
Definition:
Approved
Series goal:
None
Implementation:
Beta Available
Milestone target:
milestone icon 1.4
Started by
r.roeterdink on 2017-02-07

Related branches

Sprints

Whiteboard

Partially implemented in X3863.

JSON reading and other fixes implemented in: X4188, X4189, X4190, X4191, X4192, and X4193.

(?)

Work Items

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