Mesh leakage Temp& Ground Temp of Parabolic Dish.Help

Hello All,
It is a Prabolic Dish made up of mesh surface flat panels(16 of them).So at higher freq, power getting transmitted though dish more then what it gets reflected due to resolution of wire mesh.
Generally we calculate the mesh leakage temp by calculating the power getting transmitted through dish surface multiplied by ground temp. This uses the Feed Antenna radiation pattern which is generally confined to dish area.
What is the best method to calculate Mesh Leakage temp of Dish antenna which then contributes to System temp value? Mesh leakage temp is generally low of the order of 10K or so , but is there any other way to calcluate it and reduce it.
Making surface of dish solid is not a option at all and mesh resolution varies across surface with higher resolution at center then at edge of the dish.
Anyone has calculated Mesh leakage temp before?
What ground temperature is used when the ground is not perfectly absorptive?
Thanks in advance.