[esp-r] Re: high longware flux

[Jon Hand]

The longwave flux warning is triggered if the longwave exchange is over a certain value.
The value is based on calculations which are sensitive to the solar angle and humidity
and the properties of the surface.  This is not an issue if it happens a few times in a simulation.

If it happens several hundred times then it may be that there is some questionable data
in your climate file.  The warning tends to happen with surfaces that mostly face the sky.

The other factor is the thermophysical properties of the construction.  A very thin
metal foil over a thick insulation could result in this type of warning.  Running at a
shorter timestep can help to make the estimate of long wave radiant exchange
more accurate.

-ESRU
________________________________________
From: esp-r-bounces at lists.strath.ac.uk [esp-r-bounces at lists.strath.ac.uk] On Behalf Of 王菊花 [luckygrass100 at hotmail.com]
Sent: 25 May 2010 10:42
To: esp-r at lists.strath.ac.uk
Subject: [esp-r]  high longware flux

Dear everyone,
        Have you met the similar warning that “a longware flux of -496 Watts has been calculated for wall-4:6-2.This is considered high and a correlation will be used” when simulating?What gives rise to so high longware flux possibly?Will the correlation cause wrong simulation results?So complicated!



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