Confused about units of gradient()

[whannah1]

I have some global data and for consistency with an old paper I need to calculate a temperature gradient in units of Kelvin per 100km. However, I'm not quite sure what the units are for the quantities coming out of the gradient() operator. I assume it's Kelvin per degree lat/lon... but that would carry the usual issues around the poles, so it must be something else... right?

I looked through the documentation and github issues and couldn't find anyone discussing this.

[rajeeja]

Hi @whannah1, The gradient() operator in uxarray performs calculations on a unit sphere, so the output units are Kelvin per Radian (since your data is in Kelvin).

To convert this to Kelvin per 100km, I think you need to apply the scaling factor for the Earth's radius manually; something like:

Convert from K/rad to K/km by dividing by the Earth's radius (~6371 km).
Multiply by 100 to get K/100km.
So, gradient_k_per_100km = gradient_k_per_rad * (100 / 6371)."

[whannah1]

Awesome - this is so helpful - thank you!