Could not find these in my book but I found something I think might them online (is this correct):

Net radiation balance: R_NET = SW↓ - SW↑ + LW↓ - LW↑

Complete energy balance: R_NET - G = H + LE

Were H and LE are sensible and latent heat fluxes, and G is the ground heat flux.

Are these right?

Please help

Thank you

  • 2
    $\begingroup$ That can't be answer unless you specify the kind of surface you are talking about (dry, wet, ice) and what the letters means. SW and LW are pretty standard. But what are G, H and LE? $\endgroup$ Mar 1 '18 at 23:49
  • 1
    $\begingroup$ H and LE are sensible and latent heat. $\endgroup$
    – Communisty
    Mar 2 '18 at 9:13
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    $\begingroup$ And G is ground heat flux. There's sometimes also an S for above-ground storage heat flux (in biomass, concrete, etc) and very occasionally a biochemical storage flux term (i.e., photosynthesis). $\endgroup$
    – Deditos
    Mar 2 '18 at 9:53
  • $\begingroup$ @CamiloRada I believe this applies to most surfaces. As Deditos identified, there can be extra flux terms, but the original terms hold valid in any situation regardless of surface type. $\endgroup$
    – DavidH
    Mar 2 '18 at 16:36
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    $\begingroup$ @DavidH After the terms have been explained I would agree with you. I'm only familiar with glacier energy balance, and beside using other letters for each term, we usually write it differently, splitting some terms into two or more components for independent processes and usually writing it to solve for the energy available for melting. $\endgroup$ Mar 2 '18 at 17:35

Yes, these are the correct terms. The first equation is generally termed the 'surface radiation budget' and the second the 'surface energy budget'.

As @Deditos pointed out, additional terms for biological storage and flux can be added and are in fact important sources when considering a microclimate, and these would generally be placed into the surface energy budget.

Another form of the first equation is

Rn = ϵLW↓ − σϵT_s^4 + (1−α)SW↓

Where ϵ is the longwave emissivity of the surface, σ is the Stephan-Boltzman constant, T_s is the surface temperature, and α is the albedo (see Huber et al., section 3.2).

In certain circumstances, it is useful to set them equal to each other by solving for Rn, so you may also see

ϵLW↓ − σϵT_s^4 + (1−α)SW↓ = G + H + LE + (S + B)

Where B is the biological flux.


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