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Can't find the Dynamic weather voice in Me


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I dug into this years ago and finally gave up due to a lack of PhD level education in the field of meteorology. Nothing much seems to have changed since then. 🙄  Having been a professional pilot for over 40 years, I have a minor understanding of the basics of weather but I am severely challenged by the mechanics of the ME here in DCS World. I brought up the instructions in the pdf and, try as I might, was completely unable to place a low and a high on the same map. I really do appreciate the effort that has gone into this piece of work and I've not given up on it yet but it would be very helpful if someone that actually does have some training in meteorology/DCS World ME mechanics to expand a bit on the instructions for building some dynamic weather. This would be huge for the mission builders like me out there.

[sIGPIC][/sIGPIC]

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Most of the parameters to adjust are geometric and not meteorological. Here's an example of a dual quantity system on Marianas with a high and a low plus some adjustments:

  • Baric system: Doesn't matter since values are manually edited
  • Systems quantity: 1 of 2
  • Pressure deviations: Doesn't matter since values are manually edited

Don't touch the above values or press the Generate button or it'll generate new random values overwriting our custom ones.

#1

  • X/Y: 0/0 position at the center of the map to start
  • Spread: 100,000 meters is easy to see to start
  • Ellipicity: 0 circular to start
  • Pressure excess: 1 Pa to start (H system)
  • Rotation: 0 it's circular so rotating the ellipse is currently meaningless anyway

#2 Same as #1 except:

  • X/Y: 200,000 / 0 to separate their centers
  • Pressure excess: -1 Pa to start (L system)

After adjusting any value cycle selection of the weather edit button the left toolbar to refresh the visual display as needed.

Initial setup looks like this

image.png

The circles represent some kind of partial radius of effect as I found that about double that range the effects vanish to +-0 Pa. I believe the shape is a Gaussian type "Bell" curve carried out to at least 3 standard deviations. The centers are the maximum +-excess (in our case +-1 Pa) from standard. A good mental visualization is hills and valleys like this image.png

Standard atmosphere is 101,300 Pa so +-1 is +-0.001% of an atmosphere which is basically nothing. And the winds are calm accordingly. If you think to your highest/lowest altimeter setting it might have been 29 to 31"Hg which is about 3%. Let's rearrange the circles side by side and make everything a bit bigger to include more wind dots. At the same time make the pressure deviations +-500 Pa to get some light winds. That's not a lot of pressure deviation but it's a lot of pressure gradient because these high and low systems are so close together.

image.png

Those are 100/-150 km X/Y, 150km spread, +500Pa and 100/-600 km X/Y, 150km spread, -500 Pa respectively for the high and low systems. The wind is not blowing directly from high to low pressure like one would expect. Wind spirals out down the mountain from a high CW and down into a low CCW. Wind speed is dependent on the pressure gradient, steeper being faster wind.

Tinkering with wind speed and direction can be tricky. It would be really, really helpful to visualize the topology of the pressure field if DCS drew in an isobar graph. If you want mostly the same speed and direction you want big, big systems with far, far away centers probably off the visible map entirely. Look at some real world weather reports to get a feeling of typical pressure center separation and magnitudes. One visualization is that if you imagine the pressure graph as a topo map then looking directly downhill wind blows from your left to right.

More advanced you can start to shape and rotate the pressure objects from being simple circles. Ellipticity is a measure of how not-circular an ellipse is. 0 is a circle. I can't figure out what definition DCS is using because it's not the standard one ( a-c / a ). All I can figure is that 1-6 produces increasingly flat ellipses. Negative values are the same as positive. Numbers between 0 and 1 are doing nutty things. Rotation is radians the system is rotated clockwise. If you want the blob of air pressure to be NW to SE instead of W to E you want a 45° rotation CW or 2pi/8 = 0.39. Since ellipses are symmetric 0 to pi is all you need.

Lastly pressure determines where clouds form but the air in DCS is so dry it takes extreme low pressure and temperature to make even a modest cloud effect. It's usually not worth it.

If you really want a particular wind field you start with all the arrows of wind direction and then make another set of  arrows crossing those at right angles in a different color such that if wind is blowing from N then "downhill pressure" is east or the equivalent rotation. Just check that if wind would be blowing from your left to right you'd be facing low pressure. Then you take that pressure gradient map and try to construct pressure zones according to where all the "downhill" arrows are pointed.

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Thank you so very much for this explanation Frederf! I can now easily see that one of my problems was that I kept hitting the "Generate" button to make something happen. It would be awesome if ED figured out how to have this actually affect the clouds and visibility over the entire map, which is after all,  mostly why we are going through this exercise in the first place!

[sIGPIC][/sIGPIC]

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Thank you so very much for this explanation Frederf! I can now easily see that one of my problems was that I kept hitting the "Generate" button to make something happen. It would be awesome if ED figured out how to have this actually affect the clouds and visibility over the entire map.

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