Two-Way Coupling: Pass Analytical Coupling Fields from IPE to WAM

[joeschoonover]

We are ready to begin passing data from IPE to WAM. We need to verify that that the IPE to WAM interpolation is functioning as expected.

Condition for satisfaction : Prove that the mediator is properly interpolating from the IPE grid to the WAM grid.

[rmontuoro]

Created two_way_coupling branch to test that the SWPC mediator is properly transferring and interpolating fields from IPE to WAM.

[joeschoonover]

One the WAM-side, there are arrays that will need to be filled in. These array can be learned from commits associated with issue NOAA-SWPC/WAM-IPE#58

[rmontuoro]

Performed preliminary 2-way coupling tests with full WAM-IPE model as follows:

• meteorological fields (3d neutral wind components and neutral temperature) exported from WAM to IPE were "rerouted" from IPE to WAM through the SWPC mediator
• those fields were compared at selected vertical levels (100, 120, 140, 145)
• difference plots for the neutral temperature field are included below:

WAM level 100 (average temperature: 184.018)

WAM level 120 (average temperature: 741.915)

WAM level 140 (average temperature: 1064.81)

WAM level 145 (average temperature: 1067.64)

[rmontuoro]

Additional tests performed by exporting constant Fields from WAM to IPE and back through the SWPC mediator. Constant values were 0 and 100. Absolute difference plots (WAM import-export) are included below.

Field = 0:

WAM level 100 - 95.54 km (mindiff = 0., maxdiff = 2.2e-309, non-zero: 297/13072)

WAM level 120 - 145.17 km (mindiff = 0., maxdiff = 2.5e-309, non-zero: 21/13072)

WAM level 140 - 305.04 km (mindiff = 0., maxdiff = 1.1e-309, non-zero: 12/13072)

WAM level 145 - 359.60 km (mindiff = 0., maxdiff = 1.2e-309, non-zero: 12/13072)

Field = 100:

WAM level 100 - 95.54 km (mindiff = -100., maxdiff = 0., non-zero: 319/13072)

WAM level 120 - 145.17 km (mindiff = -100., maxdiff = 0., non-zero: 21/13072)

WAM level 140 - 305.04 km (mindiff = -100., maxdiff = 0., non-zero: 12/13072)

WAM level 145 - 359.60 km (mindiff = -100., maxdiff = 0., non-zero: 12/13072)

[rmontuoro]

Updated two_way_coupling branch to include test code used for preliminary experiments above. From now on, this branch is only intended to be used for testing purposes.

[rmontuoro]

More tests performed by setting Fields to 0 and 100 in IPE and exporting them to WAM through the SWPC mediator. Absolute difference plots (WAM import-export) are identical to previous experiment. Results are summarized below.

Field = 0.

WAM Level	min value	max value	non-zero
100	0.	9.83424e-311	298
120	0.	8.66691e-310	20
140	0.	8.48798e-314	11
145	0.	8.48798e-314	11

Field = 100.

WAM Level	min value	max value	non-zero
100	-100.	0.	319
120	-100.	0.	21
140	-100.	0.	12
145	-100.	0.	12

[rmontuoro]

Additional 2-way coupling tests performed using a toy WAM model on a regular grid and evenly-spaced vertical levels. These tests are aimed at investigating the accuracy of 2-way coupling as fields are exported from WAM to IPE, then rerouted from IPE to WAM.

Tested WAM fields are built using the following analytical formula:

f(i, j, k) = ifield * sin(2*PI*i/NLONG) * (sin(4*PI*j/total_count(2)) + sin(8*PI*k/total_count(3)))

where:

• ifield is the field index (1,...,N. of exported fields)
• NLONG is the grid's total number of longitude points
• total_count(i) is the total number of points in the local region for coordinate i

Test WAM levels are:

WAM Level N.	value (km)
1	90.000000
2	123.333333
3	156.666667
4	190.000000
5	223.333333
6	256.666667
7	290.000000
8	323.333333
9	356.666667
10	390.000000
11	423.333333
12	456.666667
13	490.000000
14	523.333333
15	556.666667
16	590.000000
17	623.333333
18	656.666667
19	690.000000
20	723.333333
21	756.666667
22	790.000000
23	823.333333
24	856.666667
25	890.000000

Intermediate levels in the SWPC mediator are provided by WAM and set equal to the WAM levels.

WAM Level 1

• exported

  

• imported

  

WAM Level 3

• exported

  

• imported

  

[rmontuoro]

Here's a section of the IPE mesh:

[joeschoonover]

Posting this figure on behalf of @oehmke