Structuring solar meteorology terms

[carstenhoyerklick]

Description of the issue

We want to introduce a number of new terms regarding solar meteorology into the OEO. The first question we should discuss is, how to structure them into the ontology. The is a number issues associated with it:

"Type" of solar radiation

• irradiation is an energy measured within a certain period of time (e.g. aggregated over an hour)
• irradiance is a power at an instant. Irradiance integrated over time is an irradiation.
• illuminace ist spectrally weighted irradiance focused on daylighting applications.

The "spatial distribution of radiation"

• direct radiation directly comes from the sun
• diffuse radiation is reflected and scattered e.g. by air molecules or clouds
• global radiation is the sum of direct and diffuse

The way of measurement:

• horizontal is meased on a horizontal plane which is parallel to the earth surface
• direct is measured on a plane which is always directed towards the sun, e.g. the plane is perpendicular to the incomming direct light rays, a tracking surface
• titlted is an arbitrary tilted plane (e.g. a tilted roof-top).

These properties can be combined, e.g. we have

• "direct normal irradiance" which is a power of solar radiation measured on a surface oriented towards the sun and only considers the radiation which comes directly from the sun.
• "global horizontal irradiation" is an energy which is collected on a flat horizontal surface from all directions.

The main questions is:
Do we need to define all permutations of the three groups as separate terms

• direct normal irradiance
• direct normal irradiation
• direct normal illuminance
• direct horizontal irradiance
• direct horizontal irradiation
• direct horizontal illuminance
• .....

or can we define just the single words and can use combinations of the terms to annotate the data.

One further question:
We have

• solar energy in in continuant->specifically dependent continuant -> quality -> energy -> radiative energy
• solar radiation in occurrent -> process -> radiation -> solar radiation

Should we place energy related terms as irradiation in the first group and power related terms as irradiance in the second group? Or should we restructure this?

Ideas of solution

Option 1)

• We just define the single words an can use combinations of it
  Optoin 2)
• We need to have definitions for all permutations.

Workflow checklist

• I discussed the issue with someone else than me before working on a solution
• I already read the latest version of the workflow for this repository
• The goal of this ontology is clear to me

I am aware that

• [x ] every entry in the ontology should have a definition
• [x ] classes should arise from concepts rather than from words

[l-emele]

"Type" of solar radiation

* irradiation is an energy measured within a certain period of time (e.g. aggregated over an hour)

* irradiance is a power at an instant. Irradiance integrated over time is an irradiation.

* illuminace ist spectrally weighted irradiance focused on daylighting applications.

Things that you measure are neither energies nor processes but quantity values of some energies or processes, so these would be all in continuant -> generically dependent continuant -> information content entity -> quantity value. There we already have areal solar power density (alternative term: irradiance) and areal solar energy density (alternative term: irradiation). Concepts like direct normal irradiance will probably be subclasses of these. Illuminance however is a completely new concept, at least I did not find this word in the OEO.

The "spatial distribution of radiation"

* direct radiation directly comes from the sun

* diffuse radiation is reflected and scattered e.g. by air molecules or clouds

* global radiation is the sum of direct and diffuse

These sound to me as different ways, the light travels from the sun through the atmosphere, so I assume, these processes are subprocesses of our more general solar radiation class (Definition: Solar radiation is radiation that is emitted by the sun.).

[stap-m]

Things that you measure are neither energies nor processes but quantity values of some energies or processes, so these would be all in continuant -> generically dependent continuant -> information content entity -> quantity value.

Usually, all quantity values should be related to their "entity in reality", which in the case of irradiation seems to be solar radiation.
With for energy transformation processes we introduced power as process attribute. We could think about having irradiance as its subclass, or directly link it to solar irradiation as well.

By the way: I think radiation should be classified as subclass of energy transformation/ energy tranfser.

[l-emele]

By the way: I think radiation should be classified as subclass of energy transformation/ energy tranfser.

I agree, but then it should be redefined to: Radiation is an energy transfer by emitting or transmitting energy in the form of waves or particles through a spatial region or a material entity.