IR Waves look odd when level of Greenhouse gases decreases quickly

[Nancy-Salpepi]

Test device
iPad 9th generation and MacBook

Operating System
iPadOS16.2 and macOS 13.1

Browser
safari and chrome

Problem description
For phetsims/qa#885, on the Waves Screen I noticed that when I decrease the concentrations levels by large increments, the coloring in IR waves looks odd (sort of clumpy).
I do not see this in the published prototype.

Steps to reproduce

1. On the waves screen, press the Start Sunlight button
2. Wait a couple of seconds, then move the concentration slider all the way to 'none.'

Visuals

waves.mp4

Troubleshooting information: !!!!! DO NOT EDIT !!!!! Name: ‪Greenhouse Effect‬ URL: https://phet-dev.colorado.edu/html/greenhouse-effect/1.1.0-rc.2/phet/greenhouse-effect_all_phet.html Version: 1.1.0-rc.2 2023-01-18 00:39:07 UTC Features missing: applicationcache, applicationcache, touch Flags: pixelRatioScaling User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/109.0.0.0 Safari/537.36 Language: en-US Window: 1275x781 Pixel Ratio: 1.7999999523162842/1 WebGL: WebGL 1.0 (OpenGL ES 2.0 Chromium) GLSL: WebGL GLSL ES 1.0 (OpenGL ES GLSL ES 1.0 Chromium) Vendor: WebKit (WebKit WebGL) Vertex: attribs: 16 varying: 31 uniform: 1024 Texture: size: 16384 imageUnits: 16 (vertex: 16, combined: 32) Max viewport: 16384x16384 OES_texture_float: true Dependencies JSON: {}

[arouinfar]

We use both stroke weight and opacity to communicate the intensity of the radiation. The varying thickness was added to address #84. We considered moving to a constant opacity, but we lose a lot of the dynamic range that way. Ultimately, the design team decided that the artifacts created by overlapping opacities were an acceptable trade-off.