The ground surface temperature is $10\mathrm{.}2$C on a calm, clear night is exposed to a sky temperature of $-5\mathrm{.}9$oC and an ambient air temperature of $14\mathrm{.}2$oC$.$ For an assumed convection coefficient of $10$ W$$m$-2$K$-1,$ an emissivity of $0\mathrm{.}85,$ and ignoring conduction to$/$from below, the heat flux at the ground surface is $\_\_\_\_$ W$$m$-2.($provide answer to one decimal place, and pay attention to sign convention, where a positive heat flux is into the ground$)$