SysML v2: Unit degree Celsius (°C) related to CelsiusTemperatureValue

[Martin]

Hello all,

the SysML v2 domain libraries for quantities and units specify for instance TemperatureValue as alias for ThermodynamicTemperatureValue with unit ThermodynamicTemperatureUnit such as kelvin or degree Rankine.

This allows one to express a constraint such as:

constraint canBatheBabyInKelvin {

    in temperature defined by ISQThermodynamics::TemperatureValue;
    temperature >= 309.15 [SI::K] and temperature <= 310.15 [SI::K]
}

Now I would like to express this constraint by using degree Celsius (°C):

constraint canBatheBabyInDegreeCelsius {

    in temperature defined by ISQThermodynamics::CelsiusTemperatureValue;
    temperature >= 36 [SI::'°C_abs'] and temperature <= 37 [SI::'°C_abs']
}

The issue is that CelsiusTemperatureValue expects units specializing CelsiusTemperatureUnit and there seems to be none. °C_abs specializes IntervalScale.

a) What is the expected modeling of canBatheBabyInDegreeCelsius using degree Celsius (°C) in SysML v2?

b) What is the expected way to model the constraint input? 
    1. in temperature defined by ISQThermodynamics::TemperatureValue;
    2. in temperature subsets ISQThermodynamics::temperature;
    3. in temperature redefines ISQThermodynamics::temperature;
    4. in temperature references ISQThermodynamics::temperature;

Thank you very much in advance!

Best regards,
Martin