So a relatively simple question motivated by seeing some new ice form...
Do we know what day is breakeven for heat flux, counting only radiation, at various latitudes? Assume clear skies (though I'd be curious for cloudy too), and open water at 0C for albedo/blackbody purposes.
That is - if we only look at heat gained from the sun and heat lost via longwave to space (ignore atmospheric interaction, upwelling, currents, etc), what day of the solar year does this breakeven occur at various latitudes?
