Super low roof emissivity in the new surface data

[Yuan Sun]

Hi all,

I am running CTSM5.2 and found that roof emissivity for TBD in somewhere (e.g., UK ) is 0.04. It seems to be rather small representing TBD emissivity.

I uploaded two plots. The UK one is generated by the mksurfdata_esmf in CTSM5.2.005. The global one is from inputdata/lnd/clm2/surfdata_esmf/ctsm5.2.0/surfdata_0.9x1.25_hist_1850_78pfts_c240216.nc.

How to interpret it? Thanks for any comments.

Best,
Yuan

 

[Yuan Sun]

There are three grids having TBD fraction and 0.04 roof emissivity for TBD in the global surface dataset.
[lsmlat, lsmlon]: [138, 40], [139, 40], [150, 0] (london, UK)

HD and MD also meet the same issues where roof emissivity is 0.04.

 

[oleson]

The Jackson et al. dataset specifies that the majority of roofs in that region are made out of galvanized steel (zinc coated steel) which has an emissivity of 0.04 according to the literature. New datasets being developed by Yifan Cheng/Lei Zhao indicate that the assumed construction is inaccurate and/or these emissivity values are likely too low even for metal roofs.

 

[Yuan Sun]

The Jackson et al. dataset specifies that the majority of roofs in that region are made out of galvanized steel (zinc coated steel) which has an emissivity of 0.04 according to the literature. New datasets being developed by Yifan Cheng/Lei Zhao indicate that the assumed construction is inaccurate and/or these emissivity values are likely too low even for metal roofs.

Hi Keith,

Thanks for your explanation. I got it.

Best,
Yuan