<p>On the synoptic scale (thinking along the lines of cyclones, weather fronts etc.), then that's a pretty significant drop in that amount of time.</p>

<p>A <strong>bomb</strong> or <strong>explosive cycogenesis</strong> in meteorological terms is defined as a drop of at least 24mb in 24 <em>hours</em>, so your observation easily fits this description of being a significant rapid pressure change. There's a list of similar events <a href="http://en.wikipedia.org/wiki/Rapid_deepening">here</a>.</p>

<p>You ask what the significance would be at the surface, and only 80m up, which makes me think you might be talking about smaller scales (perhaps?), in which case @naught101 is right in suspecting small scale eddies from buildings could be causing the surprising readings. 80m isn't really going change the significance of an observation that much on synoptic/meso -scales.</p>

<p><em>Sources</em>:</p>

<p><a href="http://glossary.ametsoc.org/wiki/Bomb">http://glossary.ametsoc.org/wiki/Bomb</a></p>

<p><a href="http://journals.ametsoc.org/doi/abs/10.1175/1520-0493%281980%29108%3C1589%3ASDCOT%3E2.0.CO%3B2">Synoptic-Dynamic Climatology of the "Bomb"</a></p>

CC BY-SA 3.0
2015-01-23T19:10:39.970Z
This case is definitely in between meso and microscale meteorology. The only issue with the eddy idea is that the instruments are located in an isolated flat field, so it couldn't have been mechanical turbulence that played a role.
climatefreak
CC BY-SA 3.0
2015-01-12T22:33:08.860Z
2015-01-12T22:45:14.707Z
2015-01-12T22:45:14.707Z
decvalts
<p>I would be interested in seeing how significant a 5-10 mb drop in pressure would be at the surface, and 80 m in the air. The temporal scale would be 20 minutes. If the pressure starts to steadily increase after the drop in pressure, would this hint that the instruments are measuring data incorrectly, or is there something else at play?</p>

CC BY-SA 3.0
2014-09-08T06:04:01.557Z
What's the context? Just thinking if you're measuring outside a building, a change in wind direction might cause eddies that might result in a pattern like that. Or if you're in a balloon or glider, it could be due to drifting into a thermal or something.
naught101
CC BY-SA 3.0
2015-01-14T04:21:16.897Z
The answer below reinforces the comment above. What is the context?
Isopycnal Oscillation
<meteorology><barometric-pressure><instrumentation>
How significant is a 5-10 mb drop in pressure over a 20 minute period?
climatefreak
# How significant is a 5-10 mb drop in pressure over a 20 minute period?

(Asked by: username_0 on 2014-08-27)

I would be interested in seeing how significant a 5-10 mb drop in pressure would be at the surface, and 80 m in the air. The temporal scale would be 20 minutes. If the pressure starts to steadily increase after the drop in pressure, would this hint that the instruments are measuring data incorrectly, or is there something else at play?

**Tags:** meteorology, barometric-pressure, instrumentation

> **Comments:**
> **username_1**: What's the context? Just thinking if you're measuring outside a building, a change in wind direction might cause eddies that might result in a pattern like that. Or if you're in a balloon or glider, it could be due to drifting into a thermal or something.  
> **username_2**: The answer below reinforces the comment above. What is the context?  

---

## 1 answers

### Answer by username_3 on 2015-01-12. Score: 6

On the synoptic scale (thinking along the lines of cyclones, weather fronts etc.), then that's a pretty significant drop in that amount of time.

A **bomb** or **explosive cycogenesis** in meteorological terms is defined as a drop of at least 24mb in 24 *hours*, so your observation easily fits this description of being a significant rapid pressure change. There's a list of similar events [here](http://en.wikipedia.org/wiki/Rapid_deepening).

You ask what the significance would be at the surface, and only 80m up, which makes me think you might be talking about smaller scales (perhaps?), in which case @username_1 is right in suspecting small scale eddies from buildings could be causing the surprising readings. 80m isn't really going change the significance of an observation that much on synoptic/meso -scales.

*Sources*:

<http://glossary.ametsoc.org/wiki/Bomb>

[Synoptic-Dynamic Climatology of the "Bomb"](http://journals.ametsoc.org/doi/abs/10.1175/1520-0493%281980%29108%3C1589%3ASDCOT%3E2.0.CO%3B2)

> **Comments:**
> **username_0**: This case is definitely in between meso and microscale meteorology. The only issue with the eddy idea is that the instruments are located in an isolated flat field, so it couldn't have been mechanical turbulence that played a role.  

---

