<p>The way I understand it, the net longwave radiation $L^\star:=L^\downarrow-L^\uparrow$ (maybe with different sign), i.e. the difference between downwelling and upwelling radiation, can be viewed as a vector field (with vanishing horizontal components under the assumption of homogeneous horizontal radiation distribution). This vector field has a divergence $\nabla\cdot L^\star=\frac{\partial L^\star}{\partial z}$. </p>

<p>This term occurs in equation (1) of the paper you referenced as part of the heating rate. Since non-vanishing divergence is in a vector field is associated with the field having a source or sink, this corresponds to heating/cooling of the atmosphere.</p>

CC BY-SA 3.0
2016-03-07T10:12:55.880Z
Ah, of course, thanks. I was thinking in terms of a single layer land-surface model. That'll teach me to read the paper first :/
naught101
CC BY-SA 3.0
2016-03-07T09:25:14.620Z
2016-03-07T09:25:14.620Z
Christoph
<p>What is radiation divergence, in the context of atmospheric physics? For example, the phrase is used in <a href="http://onlinelibrary.wiley.com/doi/10.1029/2009JD013074/abstract">this paper</a>.</p>

<atmospheric-radiation>
What is radiation divergence?
naught101
# What is radiation divergence?

(Asked by: username_0 on 2016-03-01)

What is radiation divergence, in the context of atmospheric physics? For example, the phrase is used in [this paper](http://onlinelibrary.wiley.com/doi/10.1029/2009JD013074/abstract).

**Tags:** atmospheric-radiation


---

## 1 answers

### Answer by username_1 on 2016-03-07. Score: 3 | Accepted answer

The way I understand it, the net longwave radiation $L^\star:=L^\downarrow-L^\uparrow$ (maybe with different sign), i.e. the difference between downwelling and upwelling radiation, can be viewed as a vector field (with vanishing horizontal components under the assumption of homogeneous horizontal radiation distribution). This vector field has a divergence $\nabla\cdot L^\star=\frac{\partial L^\star}{\partial z}$.

This term occurs in equation (1) of the paper you referenced as part of the heating rate. Since non-vanishing divergence is in a vector field is associated with the field having a source or sink, this corresponds to heating/cooling of the atmosphere.

> **Comments:**
> **username_0**: Ah, of course, thanks. I was thinking in terms of a single layer land-surface model. That'll teach me to read the paper first :/  

---

