Weather

Overview

Haystack standardizes the modeling of weather stations and their associated observations. The stations themselves are modeled using the WeatherStation spec. The observations are modeled as normalized points along with the weather marker tag.

Stations

Weather stations model a geographic location where observations are taken. Stations might be an official government location; for example in the US the NOAA provides an extensive database of station locations and their associated data. Many online weather services are virtual and approximate data using several physical stations. Or, it is possible to model site local weather sensors using the Haystack weather model.

All weather stations must define the weatherStation marker tag along with the appropriate geoPlace tags. The tz tag must also be defined.

Here is an example of a weather station entity:

id: @richmond
dis: "Weather for Richmond VA"
weatherStation
geoCoord: C(37.542979,-77.469092)
geoCity: "Richmond"
geoCountry: "US"
geoState: "VA"
tz: "New_York"

When a weather station is available for a site, the site should define the weatherStationRef tag to model the relationship.

Points

All weather observation points must define the following tags:

• weather: marker to indicate entity is a weather point
• weatherStationRef: parent weather station associated with the point
• sensor: all observation points are considered sensor points

Additionally the standard point tags must be defined including point, kind, unit, and enum.

The following are the standardized weather points that may be defined for a given station:

• air temp: dry bulb temperature in °C or °F
• air wetBulb: web bulb temperature in °C or °F
• air feelsLike: apparent temperature in °C or °F
• air dewPoint: dew point temperature in °C or °F
• air humidity: relative humidity in %RH
• air enthalpy: total heat content in kJ/kg or BTU/lb
• atmospheric pressure: barometric pressure in millibar or inHg
• cloudage: cloudiness as percentage
• daytime: boolean point that is true between sunrise and sunset
• precipitation: fallen atmospheric water vapor in mm or in
• solar irradiance: energy received from sun in W/m²
• weatherCond: enumeration for clear, cloudy, rain, snow, etc
• wind speed: wind speed in km/h or mph
• wind direction: direction that wind originates in degrees
• visibility: distance at which light can be discerned in km or mile

Example of a weather observation point:

// air temperature with a current value
id: @richmond.temp
dis: "Temperature for Richmond VA"
weather
air
temp
sensor
point
unit: "°F"
kind: "Number"
tz: "New_York"
weatherStationRef: @richmond
cur
curVal: 56°F
curStatus: "ok"