<p>Yes according to <a href="https://www.biointeractive.org/sites/default/files/skincolorselection-educator-act.pdf" rel="nofollow noreferrer">https://www.biointeractive.org/sites/default/files/skincolorselection-educator-act.pdf</a> (<a href="https://web.archive.org/web/20210906203902/https://www.biointeractive.org/sites/default/files/skincolorselection-educator-act.pdf" rel="nofollow noreferrer">mirror</a>):</p>
<blockquote>
<p>How do you explain the relationship between the UV Index and latitude? (In other words, why does UV
intensity change with latitude?)</p>
<p>The answer has to do with the <strong>angle of Earth relative to the sun</strong>. Latitudes at the equator receive direct sunlight
year-round. Latitudes toward the poles receive sunlight at an oblique angle, which means that the same amount of
radiation is spread out over a larger area than at the equator.</p>
</blockquote>
<hr />
<p>Now let's try to find to what extent the amount of UVA radiations one receives depend on the latitude one is located:</p>
<p>The 1995 study {1} looked at measured UVA in 4 cities in Chile with different latitudes (but some of them have different altitude, so this biases the comparison).</p>
<p><a href="https://i.sstatic.net/ayQKf.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/ayQKf.png" alt="enter image description here" /></a></p>
<p><a href="https://i.sstatic.net/wrXUg.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/wrXUg.png" alt="enter image description here" /></a></p>
<p>As a reminder: UVA (315-400 nm); UVB (280-315 nm); UVC (100-280 nm). So only the table mentions UVA (the histogram only mentions UVB).</p>
<p>I'd definitely be interested in more thorough studies.</p>
<hr />
<p>References:</p>
<ul>
<li>{1} Cabrera, Sergio, Salvador Bozzo, and Humberto Fuenzalida. &quot;Variations in UV radiation in Chile.&quot; Journal of Photochemistry and Photobiology B: Biology 28, no. 2 (1995): 137-142. <a href="https://doi.org/10.1016/1011-1344(94)07103-U" rel="nofollow noreferrer">https://doi.org/10.1016/1011-1344(94)07103-U</a></li>
</ul>

CC BY-SA 4.0
2021-09-05T20:50:25.633Z
2021-09-06T20:55:29.227Z
2021-09-06T20:55:29.227Z
Franck Dernoncourt
<p>I wonder whether the amount of UVA radiations one receives depends on the latitude one is located, and if so, to what extent? I looked at UV indices of different cities, but those are useless since they mostly take into account UVB, which unlike UVA depends on the weather condition (e.g., the presence of clouds will decrease UVB radiations but not UVA radiations {1}).</p>
<hr />
<p>References:</p>
<ul>
<li>{1} Calbó, Josep, David Pages, and Josep‐Abel González. &quot;Empirical studies of cloud effects on UV radiation: A review.&quot; Reviews of Geophysics 43, no. 2 (2005). <a href="https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2004RG000155" rel="nofollow noreferrer">https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2004RG000155</a></li>
</ul>

<uv-light>
Does the amount of UVA radiations one receives depend on the latitude one is located, and if so, to what extent?
Franck Dernoncourt
# Does the amount of UVA radiations one receives depend on the latitude one is located, and if so, to what extent?

(Asked by: username_0 on 2021-09-05)

I wonder whether the amount of UVA radiations one receives depends on the latitude one is located, and if so, to what extent? I looked at UV indices of different cities, but those are useless since they mostly take into account UVB, which unlike UVA depends on the weather condition (e.g., the presence of clouds will decrease UVB radiations but not UVA radiations {1}).

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References:

* {1} Calbó, Josep, David Pages, and Josep‐Abel González. "Empirical studies of cloud effects on UV radiation: A review." Reviews of Geophysics 43, no. 2 (2005). <https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2004RG000155>

**Tags:** uv-light


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## 1 answers

### Answer by username_0 on 2021-09-05. Score: 1

Yes according to <https://www.biointeractive.org/sites/default/files/skincolorselection-educator-act.pdf> ([mirror](https://web.archive.org/web/20210906203902/https://www.biointeractive.org/sites/default/files/skincolorselection-educator-act.pdf)):

> How do you explain the relationship between the UV Index and latitude? (In other words, why does UV
> intensity change with latitude?)
>
> The answer has to do with the **angle of Earth relative to the sun**. Latitudes at the equator receive direct sunlight
> year-round. Latitudes toward the poles receive sunlight at an oblique angle, which means that the same amount of
> radiation is spread out over a larger area than at the equator.

---

Now let's try to find to what extent the amount of UVA radiations one receives depend on the latitude one is located:

The 1995 study {1} looked at measured UVA in 4 cities in Chile with different latitudes (but some of them have different altitude, so this biases the comparison).

[![enter image description here](https://i.sstatic.net/ayQKf.png)](https://i.sstatic.net/ayQKf.png)

[![enter image description here](https://i.sstatic.net/wrXUg.png)](https://i.sstatic.net/wrXUg.png)

As a reminder: UVA (315-400 nm); UVB (280-315 nm); UVC (100-280 nm). So only the table mentions UVA (the histogram only mentions UVB).

I'd definitely be interested in more thorough studies.

---

References:

* {1} Cabrera, Sergio, Salvador Bozzo, and Humberto Fuenzalida. "Variations in UV radiation in Chile." Journal of Photochemistry and Photobiology B: Biology 28, no. 2 (1995): 137-142. <https://doi.org/10.1016/1011-1344(94)07103-U>


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