Error in CCL calculation
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Here is another example (Hungerford, 14 May, middle of the day), as previously reported, showing that sometimes the software reports CCL as being lower than LCL which is not possible. I think I can see why.
Many published sources recommend finding the CCL by following the saturation mixing ratio (SMR) line from the surface dewpoint until it meets the environmental temperature line. This works sometimes but is not the definition of CCL and it fails when the env. temp. line is in the unstable region (left of the dry adiabat line).
The actual definition of the CCL is the level at which an air parcel, rising convectively from the surface, reaches saturation. If the environmental temperature line is in the area of conditional stability or absolute stability (that is, to the right of the dry adiabat), the air parcel must be heated sufficiently at ground level that it then rises along a dry adiabat until it intersects the SMR line from the surface dew point. It must be buoyant until it reaches saturation, hence must be to the right of the env. temp. line at least until it reaches the CCL. Hence to find the CCL, follow the SMR line from the dew point until it intersects the env. temp. line. BUT when the env. temp. line is to the left of the dry adiabat (unstable air), the parcel rising convectively from the ground still follows the dry adiabat until it becomes saturated, so in this situation the CCL will be equal to the LCL. I assume your software is relying on the "follow the SMR until it meets the temp. line" method in all situations, including this one in which it doesn't apply. My suggestion, to fix this, is to put in a test such that if the calculated CCL comes out less than the LCL, make it equal to the LCL.
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@MartinLyster thank you for reporting this. We are aware of the issue with calculation in sounding graphs. I already forwarded the issue to the product team, however, I am not sure when this can be fixed right now.
