GEOS-Chem Classic vertical grids
On this page we provide information about the various vertical grids used in GEOS-Chem Classic.
Hybrid grid definition
A hybrid sigma-pressure grid (aka \(\eta\) grid) uses a terrain-following coordinate near the surface, which then transitions to a purely fixed-pressure coordinate.
The pressure at the bottom edge of grid box \((I,J,L)\) of a hybrid grid may be defined as:
where
\((I,J,L)\) are the lon, lat, and level indices of the grid box;
\(P_{surface}(I,J)\) is the “true” surface pressure at lon,lat location \((I,J)\);
\(A_p(L)\) are constants in surface pressure units (Pa or hPa), defined at level edges;
\(B_p(L)\) are unitless constants, defined at level edges.
The values of \(A_p(L)\) and \(B_p(L)\) specify the vertical
properties of the grid. In GEOS-Chem, you may find these values in
source code file GeosUtil/pressure_mod.F90.
The pressure at the vertical midpoint of grid box \((I,J,L)\) is computed as the average of the pressures at successive vertical edges:
An \(\eta\) coordinate can be constructed from \(P_{edge}(I,J,L)\) and \(P_{midpoint}(I,J,L)\) as follows:
where \(P_{top}\) is pressure at the top level of the vertical grid.
Specifics for GMAO vertical grids
The the \(P_{edge}(I,J,L)\) and \(P_{midpoint}(I,J,L)\) values in GMAO meteorological products vary with the topography up to 170 hPa. Skyward of 170 hPa, \(P_{edge}(I,J,L)\) and \(P_{midpoint}(I,J,L)\) remain constant for all longitudes and latitudes \((I,J)\). GMAO meteorological products use a model top of 0.01 hPa.
Vertical grids for GMAO meteorology
72-level vertical grid
This grid is used by the GEOS-FP, GEOS-IT, and MERRA-2 meteorological field products from NASA GMAO. It has 72 vertical levels and 73 edges.
Indexing
Instance |
Surface level |
Top-of-atm level |
Direction |
|---|---|---|---|
GEOS-Chem Classic using GMAO met |
1 |
72 |
|
Emissions data for GEOS-Chem |
1 |
72 |
|
Processed met fields for GEOS-Chem |
1 |
72 |
|
Raw met fields for GEOS-Chem |
72 |
1 |
|
\(A_p\) and \(B_p\)
The table below lists the \(A_p\) and \(B_p\) parameters that define the 72-level vertical grid. The level edge indices run from 1 (surface) to 73 (top-of atmosphere).
Level edge index |
\(A_p\) (hPa) |
\(B_p\) (unitless) |
|---|---|---|
1 |
0.0 |
1.0 |
2 |
0.04804826 |
0.984952 |
3 |
6.593752 |
0.963406 |
4 |
13.1348 |
0.941865 |
5 |
19.61311 |
0.920387 |
6 |
26.09201 |
0.898908 |
7 |
32.57081 |
0.877429 |
8 |
38.98201 |
0.856018 |
9 |
45.33901 |
0.8346609 |
10 |
51.69611 |
0.8133039 |
11 |
58.05321 |
0.7919469 |
12 |
64.36264 |
0.7706375 |
13 |
70.62198 |
0.7493782 |
14 |
78.83422 |
0.721166 |
15 |
89.09992 |
0.6858999 |
16 |
99.36521 |
0.6506349 |
17 |
109.1817 |
0.6158184 |
18 |
118.9586 |
0.5810415 |
19 |
128.6959 |
0.5463042 |
20 |
142.91 |
0.4945902 |
21 |
156.26 |
0.4437402 |
22 |
169.609 |
0.3928911 |
23 |
181.619 |
0.3433811 |
24 |
193.097 |
0.2944031 |
25 |
203.259 |
0.2467411 |
26 |
212.15 |
0.2003501 |
27 |
218.776 |
0.1562241 |
28 |
223.898 |
0.1136021 |
29 |
224.363 |
0.06372006 |
30 |
216.865 |
0.02801004 |
31 |
201.192 |
0.006960025 |
32 |
176.93 |
8.175413e-09 |
33 |
150.393 |
0.0 |
34 |
127.837 |
0.0 |
35 |
108.663 |
0.0 |
36 |
92.36572 |
0.0 |
37 |
78.51231 |
0.0 |
38 |
66.60341 |
0.0 |
39 |
56.38791 |
0.0 |
40 |
47.64391 |
0.0 |
41 |
40.17541 |
0.0 |
42 |
33.81001 |
0.0 |
43 |
28.36781 |
0.0 |
44 |
23.73041 |
0.0 |
45 |
19.7916 |
0.0 |
46 |
16.4571 |
0.0 |
47 |
13.6434 |
0.0 |
48 |
11.2769 |
0.0 |
49 |
9.292942 |
0.0 |
50 |
7.619842 |
0.0 |
51 |
6.216801 |
0.0 |
52 |
5.046801 |
0.0 |
53 |
4.076571 |
0.0 |
54 |
3.276431 |
0.0 |
55 |
2.620211 |
0.0 |
56 |
2.08497 |
0.0 |
57 |
1.65079 |
0.0 |
58 |
1.30051 |
0.0 |
59 |
1.01944 |
0.0 |
60 |
0.7951341 |
0.0 |
61 |
0.6167791 |
0.0 |
62 |
0.4758061 |
0.0 |
63 |
0.3650411 |
0.0 |
64 |
0.2785261 |
0.0 |
65 |
0.211349 |
0.0 |
66 |
0.159495 |
0.0 |
67 |
0.119703 |
0.0 |
68 |
0.08934502 |
0.0 |
69 |
0.06600001 |
0.0 |
70 |
0.04758501 |
0.0 |
71 |
0.0327 |
0.0 |
72 |
0.02 |
0.0 |
73 |
0.01 |
0.0 |
Pressures and altitudes
The table below lists pressures and altitudes of the 72 layer grid for a column at atmospheric sea level.
L Eta Edge Eta Mid Altitude Pressure
(unitless) (unitless) (km) (hPa)
========================================================
0.000000 80.581 0.010
72 0.000005 78.146 0.015
0.000010 76.357 0.020
71 0.000016 74.594 0.026
0.000022 73.180 0.033
70 0.000030 71.812 0.040
0.000037 70.657 0.048
69 0.000046 69.440 0.057
0.000055 68.392 0.066
68 0.000067 67.243 0.078
0.000078 66.245 0.089
67 0.000093 65.115 0.105
0.000108 64.130 0.120
66 0.000128 63.004 0.140
0.000148 62.021 0.159
65 0.000173 60.902 0.185
0.000199 59.924 0.211
64 0.000232 58.816 0.245
0.000265 57.846 0.279
63 0.000308 56.752 0.322
0.000350 55.794 0.365
62 0.000405 54.717 0.420
0.000460 53.773 0.476
61 0.000529 52.716 0.546
0.000599 51.788 0.617
60 0.000687 50.754 0.706
0.000775 49.844 0.795
59 0.000886 48.835 0.907
0.000996 47.946 1.019
58 0.001135 46.962 1.160
0.001274 46.092 1.301
57 0.001446 45.134 1.476
0.001619 44.286 1.651
56 0.001834 43.355 1.868
0.002048 42.529 2.085
55 0.002312 41.627 2.353
0.002576 40.825 2.620
54 0.002900 39.951 2.948
0.003224 39.173 3.276
53 0.003619 38.328 3.677
0.004013 37.574 4.077
52 0.004492 36.759 4.562
0.004971 36.030 5.047
51 0.005548 35.244 5.632
0.006126 34.539 6.217
50 0.006818 33.782 6.918
0.007510 33.101 7.620
49 0.008336 32.372 8.456
0.009162 31.716 9.293
48 0.010141 31.015 10.285
0.011120 30.382 11.277
47 0.012287 29.701 12.460
0.013455 29.085 13.643
46 0.014844 28.423 15.050
0.016232 27.824 16.457
45 0.017878 27.180 18.124
0.019523 26.596 19.792
44 0.021467 25.971 21.761
0.023410 25.402 23.730
43 0.025699 24.794 26.049
0.027987 24.240 28.368
42 0.030673 23.648 31.089
0.033358 23.108 33.810
41 0.036499 22.531 36.993
0.039641 22.004 40.175
40 0.043326 21.438 43.910
0.047011 20.920 47.644
39 0.051326 20.364 52.016
0.055641 19.855 56.388
38 0.060682 19.309 61.496
0.065723 18.807 66.603
37 0.071600 18.269 72.558
0.077477 17.773 78.512
36 0.084313 17.243 85.439
0.091149 16.753 92.366
35 0.099191 16.222 100.514
0.107233 15.731 108.663
34 0.116695 15.198 118.250
0.126157 14.706 127.837
33 0.137287 14.170 139.115
0.148418 13.674 150.393
32 0.161513 13.134 163.661
0.174608 12.633 176.930
31 0.190061 12.086 192.587
0.205513 11.578 208.244
30 0.223772 11.021 226.745
0.242032 10.504 245.246
29 0.263587 9.936 267.087
0.285142 9.409 288.927
28 0.309854 8.846 313.966
0.334566 8.320 339.005
27 0.353349 7.943 358.038
0.372133 7.582 377.070
26 0.390927 7.237 396.112
0.409720 6.905 415.155
25 0.428528 6.585 434.212
0.447337 6.277 453.269
24 0.466153 5.980 472.335
0.484970 5.692 491.401
23 0.503795 5.413 510.475
0.522620 5.142 529.550
22 0.541449 4.879 548.628
0.560278 4.623 567.706
21 0.579115 4.375 586.793
0.597953 4.132 605.880
20 0.616790 3.896 624.967
0.635628 3.665 644.054
19 0.654471 3.439 663.146
0.673314 3.219 682.239
18 0.685878 3.074 694.969
0.698442 2.932 707.699
17 0.711006 2.792 720.429
0.723570 2.654 733.160
16 0.736134 2.517 745.890
0.748698 2.382 758.621
15 0.761265 2.249 771.354
0.773832 2.118 784.088
14 0.786400 1.988 796.822
0.798967 1.860 809.556
13 0.809021 1.759 819.743
0.819075 1.659 829.929
12 0.826616 1.584 837.570
0.834157 1.510 845.211
11 0.841698 1.436 852.852
0.849239 1.363 860.493
10 0.856781 1.290 868.135
0.864323 1.218 875.776
9 0.871864 1.146 883.418
0.879406 1.075 891.059
8 0.886948 1.004 898.701
0.894489 0.934 906.342
7 0.902031 0.864 913.984
0.909573 0.795 921.626
6 0.917116 0.726 929.268
0.924658 0.657 936.911
5 0.932200 0.589 944.553
0.939743 0.521 952.195
4 0.947285 0.454 959.837
0.954828 0.387 967.480
3 0.962370 0.320 975.122
0.969913 0.254 982.765
2 0.977456 0.189 990.408
0.984999 0.123 998.051
1 0.992500 0.058 1005.650
1.000000 -0.006 1013.250
47-layer reduced vertical grid
In order to save computational resources, GEOS-Chem Classic can collapse the 72-level vertical grid down to a 47-level grid (with 48 edges) “on-the-fly”. Groups of 2 and 4 levels are lumped together starting at ~70 hPa. See the table below for more information.
Indexing
Instance |
Surface level |
Top-of-atm level |
Direction |
|---|---|---|---|
GEOS-Chem Classic using GMAO met |
1 |
47 |
|
Lumping of vertical levels
47-level reduced vertical grid
Bottom Bottom # levels
edge of edge prs lumped
level (hPa) together
PTOP 0.010
47 0.066 4
46 0.211 4
45 0.617 4
44 1.651 4
43 4.077 4
42 9.293 4
41 19.792 4
40 28.368 2
39 40.175 2
38 56.388 2
37 78.512 2
%%%% START LUMPING LEVELS ABOVE HERE %%%%%
1-36 Levels are the same as in the 72-layer grid
\(A_p\) and \(B_p\)
The table below lists the \(A_p\) and \(B_p\) parameters that define the 47 level reduced vertical grid. The level edge indices run from 1 (surface) to 48 (top-of atmosphere).
Level edge index |
\(A_p\) (hPa) |
\(B_p\) (unitless) |
|---|---|---|
1 |
0.0 |
1.0 |
2 |
0.04804826 |
0.984952 |
3 |
6.593752 |
0.963406 |
4 |
13.1348 |
0.941865 |
5 |
19.61311 |
0.920387 |
6 |
26.09201 |
0.898908 |
7 |
32.57081 |
0.877429 |
8 |
38.98201 |
0.856018 |
9 |
45.33901 |
0.8346609 |
10 |
51.69611 |
0.8133039 |
11 |
58.05321 |
0.7919469 |
12 |
64.36264 |
0.7706375 |
13 |
70.62198 |
0.7493782 |
14 |
78.83422 |
0.721166 |
15 |
89.09992 |
0.6858999 |
16 |
99.36521 |
0.6506349 |
17 |
109.1817 |
0.6158184 |
18 |
118.9586 |
0.5810415 |
19 |
128.6959 |
0.5463042 |
20 |
142.91 |
0.4945902 |
21 |
156.26 |
0.4437402 |
22 |
169.609 |
0.3928911 |
23 |
181.619 |
0.3433811 |
24 |
193.097 |
0.2944031 |
25 |
203.259 |
0.2467411 |
26 |
212.15 |
0.2003501 |
27 |
218.776 |
0.1562241 |
28 |
223.898 |
0.1136021 |
29 |
224.363 |
0.06372006 |
30 |
216.865 |
0.02801004 |
31 |
201.192 |
0.006960025 |
32 |
176.93 |
8.175413e-09 |
33 |
150.393 |
0.0 |
34 |
127.837 |
0.0 |
35 |
108.663 |
0.0 |
36 |
92.36572 |
0.0 |
37 |
78.51231 |
0.0 |
38 |
56.38791 |
0.0 |
39 |
40.17541 |
0.0 |
40 |
28.36781 |
0.0 |
41 |
19.7916 |
0.0 |
42 |
9.292942 |
0.0 |
43 |
4.076571 |
0.0 |
44 |
1.65079 |
0.0 |
45 |
0.6167791 |
0.0 |
46 |
0.211349 |
0.0 |
47 |
0.06600001 |
0.0 |
48 |
0.01 |
0.0 |
Pressures and altitudes
The table below lists pressures and altitudes of the 47 layer grid for a column at atmospheric sea level.
L Eta Edge Eta Mid Altitude Pressure
(unitless) (unitless) (km) (hPa)
========================================================
0.000000 80.581 0.010
47 0.000028 72.180 0.038
0.000055 68.392 0.066
46 0.000127 63.053 0.139
0.000199 59.924 0.211
45 0.000399 54.834 0.414
0.000599 51.788 0.617
44 0.001109 47.135 1.134
0.001619 44.286 1.651
43 0.002816 40.166 2.864
0.004013 37.574 4.077
42 0.006588 34.024 6.685
0.009162 31.716 9.293
41 0.014342 28.654 14.542
0.019523 26.596 19.792
40 0.023755 25.307 24.080
0.027987 24.240 28.368
39 0.033814 23.020 34.272
0.039641 22.004 40.175
38 0.047641 20.836 48.282
0.055641 19.855 56.388
37 0.066559 18.727 67.450
0.077477 17.773 78.512
36 0.084313 17.243 85.439
0.091149 16.753 92.366
35 0.099191 16.222 100.514
0.107233 15.731 108.663
34 0.116695 15.198 118.250
0.126157 14.706 127.837
33 0.137287 14.170 139.115
0.148418 13.674 150.393
32 0.161513 13.134 163.661
0.174608 12.633 176.930
31 0.190061 12.086 192.587
0.205513 11.578 208.244
30 0.223772 11.021 226.745
0.242032 10.504 245.246
29 0.263587 9.936 267.087
0.285142 9.409 288.927
28 0.309854 8.846 313.966
0.334566 8.320 339.005
27 0.353349 7.943 358.038
0.372133 7.582 377.070
26 0.390927 7.237 396.112
0.409720 6.905 415.155
25 0.428528 6.585 434.212
0.447337 6.277 453.269
24 0.466153 5.980 472.335
0.484970 5.692 491.401
23 0.503795 5.413 510.475
0.522620 5.142 529.550
22 0.541449 4.879 548.628
0.560278 4.623 567.706
21 0.579115 4.375 586.793
0.597953 4.132 605.880
20 0.616790 3.896 624.967
0.635628 3.665 644.054
19 0.654471 3.439 663.146
0.673314 3.219 682.239
18 0.685878 3.074 694.969
0.698442 2.932 707.699
17 0.711006 2.792 720.429
0.723570 2.654 733.160
16 0.736134 2.517 745.890
0.748698 2.382 758.621
15 0.761265 2.249 771.354
0.773832 2.118 784.088
14 0.786400 1.988 796.822
0.798967 1.860 809.556
13 0.809021 1.759 819.743
0.819075 1.659 829.929
12 0.826616 1.584 837.570
0.834157 1.510 845.211
11 0.841698 1.436 852.852
0.849239 1.363 860.493
10 0.856781 1.290 868.135
0.864323 1.218 875.776
9 0.871864 1.146 883.418
0.879406 1.075 891.059
8 0.886948 1.004 898.701
0.894489 0.934 906.342
7 0.902031 0.864 913.984
0.909573 0.795 921.626
6 0.917116 0.726 929.268
0.924658 0.657 936.911
5 0.932200 0.589 944.553
0.939743 0.521 952.195
4 0.947285 0.454 959.837
0.954828 0.387 967.480
3 0.962370 0.320 975.122
0.969913 0.254 982.765
2 0.977456 0.189 990.408
0.984999 0.123 998.051
1 0.992500 0.058 1005.650
1.000000 -0.006 1013.250
Vertical grids for GCAP2/GISS meteorology
102-level vertical grid
GCAP2/GISS meteorology is produced on a grid with 102 vertical levels. To reduce the amount of computational overhead, GEOS-Chem Classic can regrid this “on-the-fly” to ether a 74-level reduced vertical grid or a 40-level reduced vertical grid.
Indexing
Instance |
Surface level |
Top-of-atm level |
Direction |
|---|---|---|---|
GEOS-Chem Classic using GCAP2 met |
1 |
102 |
|
\(A_p\) and \(B_p\)
The table below lists the \(A_p\) and \(B_p\) parameters that define the 102 level vertical grid. The level edge indices run from 1 (surface) to 103 (top-of atmosphere).
Level edge index |
\(A_p\) (hPa) |
\(B_p\) (unitless) |
|---|---|---|
1 |
0.0 |
1.0 |
2 |
2.7871507 |
0.98192363 |
3 |
5.5743014 |
0.96384725 |
4 |
8.3614521 |
0.94577088 |
5 |
11.1486028 |
0.92769451 |
6 |
13.9357536 |
0.90961814 |
7 |
16.7229043 |
0.89154176 |
8 |
19.510055 |
0.87346539 |
9 |
22.2972057 |
0.85538902 |
10 |
25.0843564 |
0.83731265 |
11 |
27.8715071 |
0.81923627 |
12 |
30.6586578 |
0.8011599 |
13 |
33.4458085 |
0.78308353 |
14 |
36.2329593 |
0.76500716 |
15 |
39.02011 |
0.74693078 |
16 |
41.8087123 |
0.728845 |
17 |
44.6089278 |
0.71068389 |
18 |
47.4534183 |
0.69223563 |
19 |
50.4082336 |
0.67307185 |
20 |
53.5662786 |
0.65259001 |
21 |
57.009571 |
0.63025815 |
22 |
60.7533531 |
0.60597744 |
23 |
64.7323011 |
0.58017154 |
24 |
68.8549615 |
0.55343357 |
25 |
73.0567364 |
0.5261825 |
26 |
77.2969797 |
0.49868193 |
27 |
81.5364973 |
0.47118607 |
28 |
85.734643 |
0.44395854 |
29 |
89.8565776 |
0.41722528 |
30 |
93.8754457 |
0.39116047 |
31 |
97.7709243 |
0.36589591 |
32 |
101.5277712 |
0.34153047 |
33 |
105.1350991 |
0.31813474 |
34 |
108.5878272 |
0.2957417 |
35 |
111.8859556 |
0.27435132 |
36 |
115.03021 |
0.25395891 |
37 |
118.0249453 |
0.23453623 |
38 |
120.8854039 |
0.21598441 |
39 |
123.6326345 |
0.19816694 |
40 |
126.2811535 |
0.18098968 |
41 |
128.8360417 |
0.16441967 |
42 |
131.2987506 |
0.1484475 |
43 |
133.6736353 |
0.13304493 |
44 |
135.9708571 |
0.11814604 |
45 |
138.2013035 |
0.10368024 |
46 |
140.3700552 |
0.08961456 |
47 |
142.481467 |
0.07592077 |
48 |
144.5457005 |
0.06253295 |
49 |
146.5692881 |
0.04940875 |
50 |
148.5464231 |
0.03658583 |
51 |
150.4712991 |
0.02410183 |
52 |
152.3497225 |
0.01191911 |
53 |
154.1875 |
0.0 |
54 |
144.546875 |
0.0 |
55 |
135.1875 |
0.0 |
56 |
126.078125 |
0.0 |
57 |
117.1914062 |
0.0 |
58 |
108.5859375 |
0.0 |
59 |
100.3671875 |
0.0 |
60 |
92.5898438 |
0.0 |
61 |
85.2265625 |
0.0 |
62 |
78.2226562 |
0.0 |
63 |
71.5546875 |
0.0 |
64 |
65.2226562 |
0.0 |
65 |
59.2226562 |
0.0 |
66 |
53.5546875 |
0.0 |
67 |
48.2226562 |
0.0 |
68 |
43.2226562 |
0.0 |
69 |
38.5546875 |
0.0 |
70 |
34.2226562 |
0.0 |
71 |
30.2226562 |
0.0 |
72 |
26.5507812 |
0.0 |
73 |
23.1875 |
0.0 |
74 |
20.078125 |
0.0 |
75 |
17.1896562 |
0.0 |
76 |
14.5684375 |
0.0 |
77 |
12.2865742 |
0.0 |
78 |
10.3573086 |
0.0 |
79 |
8.735375 |
0.0 |
80 |
7.3664922 |
0.0 |
81 |
6.2100156 |
0.0 |
82 |
5.2343633 |
0.0 |
83 |
4.4119297 |
0.0 |
84 |
3.7186797 |
0.0 |
85 |
3.1341479 |
0.0 |
86 |
2.6404328 |
0.0 |
87 |
2.2207877 |
0.0 |
88 |
1.8587369 |
0.0 |
89 |
1.5477125 |
0.0 |
90 |
1.2782115 |
0.0 |
91 |
1.0427319 |
0.0 |
92 |
0.8367716 |
0.0 |
93 |
0.6514691 |
0.0 |
94 |
0.4772511 |
0.0 |
95 |
0.3168814 |
0.0 |
96 |
0.1785988 |
0.0 |
97 |
0.1 |
0.0 |
98 |
0.056 |
0.0 |
99 |
0.032 |
0.0 |
100 |
0.018 |
0.0 |
101 |
0.01 |
0.0 |
102 |
0.005 |
0.0 |
103 |
0.002 |
0.0 |
74-level reduced vertical grid
In order to save computational resources, GEOS-Chem Classic can collapse the 102-level vertical grid down to a 74-level grid (with 75 edges) “on-the-fly”. Groups of 2 and 4 levels are lumped together starting at ~85 hPa. See the table below for more information.
Indexing
Instance |
Surface level |
Top-of-atm level |
Direction |
|---|---|---|---|
GEOS-Chem Classic using GCAP2 met |
1 |
74 |
|
Lumping of vertical levels
74-level GISS grid (condensed from 102-layer grid)
Bottom Bottom # levels
edge of edge prs lumped
level (hPa) together
PTOP 0.0020000
74 0.0320000 4
73 0.3168814 4
72 1.0427319 4
71 2.2207877 4
70 4.4119297 4
69 8.7353750 4
68 17.1896562 4
67 23.1875000 2
66 30.2226562 2
65 38.5546875 2
64 48.2226562 2
63 59.2226562 2
62 71.5546875 2
61 85.2265625 2
%%%% START LUMPING LEVELS ABOVE HERE %%%%%
1-60 Levels are the same as for the 102 level vertical grid
\(A_p\) and \(B_p\)
The table below lists the \(A_p\) and \(B_p\) parameters that define the 74-level vertical grid. The level edge indices run from 1 (surface) to 75 (top-of atmosphere).
Level edge index |
\(A_p\) (hPa) |
\(B_p\) (unitless) |
|---|---|---|
1 |
0.0 |
1.0 |
2 |
2.7871507 |
0.98192363 |
3 |
5.5743014 |
0.96384725 |
4 |
8.3614521 |
0.94577088 |
5 |
11.1486028 |
0.92769451 |
6 |
13.9357536 |
0.90961814 |
7 |
16.7229043 |
0.89154176 |
8 |
19.510055 |
0.87346539 |
9 |
22.2972057 |
0.85538902 |
10 |
25.0843564 |
0.83731265 |
11 |
27.8715071 |
0.81923627 |
12 |
30.6586578 |
0.8011599 |
13 |
33.4458085 |
0.78308353 |
14 |
36.2329593 |
0.76500716 |
15 |
39.02011 |
0.74693078 |
16 |
41.8087123 |
0.728845 |
17 |
44.6089278 |
0.71068389 |
18 |
47.4534183 |
0.69223563 |
19 |
50.4082336 |
0.67307185 |
20 |
53.5662786 |
0.65259001 |
21 |
57.009571 |
0.63025815 |
22 |
60.7533531 |
0.60597744 |
23 |
64.7323011 |
0.58017154 |
24 |
68.8549615 |
0.55343357 |
25 |
73.0567364 |
0.5261825 |
26 |
77.2969797 |
0.49868193 |
27 |
81.5364973 |
0.47118607 |
28 |
85.734643 |
0.44395854 |
29 |
89.8565776 |
0.41722528 |
30 |
93.8754457 |
0.39116047 |
31 |
97.7709243 |
0.36589591 |
32 |
101.5277712 |
0.34153047 |
33 |
105.1350991 |
0.31813474 |
34 |
108.5878272 |
0.2957417 |
35 |
111.8859556 |
0.27435132 |
36 |
115.03021 |
0.25395891 |
37 |
118.0249453 |
0.23453623 |
38 |
120.8854039 |
0.21598441 |
39 |
123.6326345 |
0.19816694 |
40 |
126.2811535 |
0.18098968 |
41 |
128.8360417 |
0.16441967 |
42 |
131.2987506 |
0.1484475 |
43 |
133.6736353 |
0.13304493 |
44 |
135.9708571 |
0.11814604 |
45 |
138.2013035 |
0.10368024 |
46 |
140.3700552 |
0.08961456 |
47 |
142.481467 |
0.07592077 |
48 |
144.5457005 |
0.06253295 |
49 |
146.5692881 |
0.04940875 |
50 |
148.5464231 |
0.03658583 |
51 |
150.4712991 |
0.02410183 |
52 |
152.3497225 |
0.01191911 |
53 |
154.1875 |
0.0 |
54 |
144.546875 |
0.0 |
55 |
135.1875 |
0.0 |
56 |
126.078125 |
0.0 |
57 |
117.1914062 |
0.0 |
58 |
108.5859375 |
0.0 |
59 |
100.3671875 |
0.0 |
60 |
92.5898438 |
0.0 |
61 |
85.2265625 |
0.0 |
62 |
71.5546875 |
0.0 |
63 |
59.2226562 |
0.0 |
64 |
48.2226562 |
0.0 |
65 |
38.5546875 |
0.0 |
66 |
30.2226562 |
0.0 |
67 |
23.1875 |
0.0 |
68 |
17.1896562 |
0.0 |
69 |
8.735375 |
0.0 |
70 |
4.4119297 |
0.0 |
71 |
2.2207877 |
0.0 |
72 |
1.0427319 |
0.0 |
73 |
0.3168814 |
0.0 |
74 |
0.032 |
0.0 |
75 |
0.002 |
0.0 |
40-level reduced vertical grid
In order to save computational resources, GEOS-Chem Classic can collapse the 102-level vertical grid down to a 40-level grid (with 41 edges) “on-the-fly”.
Indexing
Instance |
Surface level |
Top-of-atm level |
Direction |
|---|---|---|---|
GEOS-Chem Classic using GCAP2 met |
1 |
40 |
|
\(A_p\) and \(B_p\)
The table below lists the \(A_p\) and \(B_p\) parameters that define the 40-level vertical grid. The level edge indices run from 1 (surface) to 41 (top-of atmosphere).
Level edge index |
\(A_p\) (hPa) |
\(B_p\) (unitless) |
|---|---|---|
1 |
0.0 |
1.0 |
2 |
3.597122 |
0.97601918 |
3 |
7.553957 |
0.94964029 |
4 |
12.05036 |
0.91966427 |
5 |
16.906475 |
0.88729017 |
6 |
22.302158 |
0.85131894 |
7 |
28.597122 |
0.80935252 |
8 |
35.791367 |
0.76139089 |
9 |
43.884892 |
0.70743405 |
10 |
52.517986 |
0.6498801 |
11 |
61.510791 |
0.58992806 |
12 |
70.683453 |
0.52877698 |
13 |
80.035971 |
0.46642686 |
14 |
89.028777 |
0.40647482 |
15 |
97.661871 |
0.34892086 |
16 |
105.755396 |
0.29496403 |
17 |
113.309353 |
0.24460432 |
18 |
120.143885 |
0.19904077 |
19 |
126.258993 |
0.15827338 |
20 |
131.834532 |
0.12110312 |
21 |
136.870504 |
0.08752998 |
22 |
141.546763 |
0.05635492 |
23 |
145.863309 |
0.02757794 |
24 |
150.0 |
0.0 |
25 |
128.0 |
0.0 |
26 |
108.0 |
0.0 |
27 |
90.0 |
0.0 |
28 |
73.0 |
0.0 |
29 |
57.0 |
0.0 |
30 |
43.0 |
0.0 |
31 |
31.0 |
0.0 |
32 |
20.0 |
0.0 |
33 |
10.0 |
0.0 |
34 |
5.62 |
0.0 |
35 |
3.16 |
0.0 |
36 |
1.78 |
0.0 |
37 |
1.0 |
0.0 |
38 |
0.562 |
0.0 |
39 |
0.316 |
0.0 |
40 |
0.178 |
0.0 |
41 |
0.1 |
0.0 |