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3. Analysis
1. Basic case (xyrad 10000 & zrad 1500)
1) Downdraft at low altitude




2) Disappearing downdraft (5~6km)


3) Generation of updraft


4) Value of z-wind at (27,30)

At xyrad 10000, the starting altitude of the downdraft is 5~6km.

2. Case 1 : small horizontal scale (xyrad 5000 & zrad 1500)
1) Downdraft at low altitude



2) Disappearing downdraft (4~5km)


3) Generation of updraft



4) Value of z-wind at (27,28)

At xyrad 5000, the starting altitude of the downdraft is 4~5km.

3. Case 2 : large horizontal scale (xyrad 25000 & zrad 1500)
1) Downdraft at low altitude





2) Disappearing downdraft (6~7km)


3) Generation of updraft

4) Value of z-wind at (30,31)


At xyrad 25000, the starting altitude of the downdraft is 6~7km.
4. Conclusion
The larger the horizontal scale, the higher the starting altitude of the downdraft.

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