Inside the material folder there is a material called M_HemispherePostProcess. Open it and in the bottom left corner is a parameter called Thickness. Use a value greater than 1.
The sphere has a radius of 50cm. So if you want to use a sphere with a radius of 1000cm you need a scale of 20. A scale of 1000 gives you a sphere with 50000cm radius => 500m.