GEOS–CHEM v6–02–05
User's Guide
Contact: Bob Yantosca (bmy@io.harvard.edu)
Appendix 3: GEOS–CHEM Vertical Levels
A3.1 Comparison of GEOS–1, GEOS–STRAT, GEOS–3, GEOS4 vertical levels
GEOS–1, GEOS–STRAT,
GEOS–3, GEOS–4 vertical levels, up to 10 km
GEOS–1, GEOS–STRAT,
GEOS–3, GEOS–4 vertical levels, up to 32 km
GEOS–1, GEOS–STRAT,
GEOS–3, GEOS–4 vertical levels, up to 80 km
Altitudes and pressures listed below were computed assuming a surface pressure of 1000 hPa.
L Sig Edge Sig Mid Altitude Pressure
(unitless) (unitless) (km) (hPa)
========================================================
0.000000 31.209 10.000
20 0.009500 26.727 19.405
0.019000 24.140 28.810
19 0.029000 22.241 38.710
0.039000 20.793 48.610
18 0.049750 19.543 59.252
0.060500 18.503 69.895
17 0.073000 17.480 82.270
0.085500 16.600 94.645
16 0.100050 15.709 109.049
0.114600 14.926 123.454
15 0.132200 14.090 140.878
0.149800 13.347 158.302
14 0.172150 12.507 180.428
0.194500 11.758 202.555
13 0.222750 10.912 230.522
0.251000 10.155 258.490
12 0.283750 9.363 290.913
0.316500 8.645 323.335
11 0.352000 7.935 358.480
0.387500 7.281 393.625
10 0.424750 6.647 430.503
0.462000 6.056 467.380
9 0.500500 5.485 505.495
0.539000 4.947 543.610
8 0.578390 4.429 582.606
0.617779 3.937 621.601
7 0.657114 3.470 660.543
0.696448 3.024 699.484
6 0.734480 2.611 737.135
0.772512 2.214 774.787
5 0.807833 1.858 809.755
0.843153 1.514 844.721
4 0.874137 1.222 875.396
0.905120 0.937 906.069
3 0.929925 0.713 930.626
0.954730 0.495 955.183
2 0.971301 0.351 971.588
0.987871 0.209 987.992
1 0.993936 0.158 993.997
1.000000 0.107 1000.000
A3.3 GEOS–STRAT vertical levels
Altitudes and pressures listed below were computed assuming a surface pressure of 1000 hPa.
L Sig Edge Sig Mid Altitude Pressure
(unitless) (unitless) (km) (hPa)
========================================================
0.000000 65.435 0.100
26 0.009979 31.155 10.078
0.019958 26.509 20.056
25 0.028825 24.115 28.922
0.037692 22.395 37.788
24 0.044794 21.298 44.890
0.051896 20.367 51.991
23 0.056574 19.824 56.668
0.061252 19.324 61.346
22 0.066873 18.773 66.966
0.072493 18.266 72.586
21 0.079233 17.709 79.325
0.085972 17.197 86.063
20 0.094035 16.635 94.126
0.102098 16.118 102.188
19 0.111722 15.551 111.811
0.121347 15.030 121.435
18 0.132807 14.460 132.894
0.144267 13.935 144.353
17 0.157881 13.360 157.965
0.171495 12.831 171.578
16 0.187044 12.272 187.125
0.202593 11.754 202.673
15 0.220273 11.208 220.351
0.237954 10.701 238.030
14 0.257977 10.166 258.051
0.278000 9.667 278.072
13 0.301500 9.120 301.570
0.325000 8.609 325.068
12 0.352500 8.050 352.565
0.380000 7.527 380.062
11 0.410000 6.992 410.059
0.440000 6.490 440.056
10 0.471500 5.992 471.553
0.503000 5.520 503.050
9 0.536500 5.045 536.546
0.570000 4.593 570.043
8 0.604500 4.149 604.540
0.639000 3.725 639.036
7 0.674500 3.307 674.533
0.710000 2.906 710.029
6 0.745000 2.526 745.026
0.780000 2.160 780.022
5 0.812500 1.831 812.519
0.845000 1.512 845.016
4 0.875060 1.225 875.073
0.905120 0.945 905.130
3 0.929925 0.720 929.932
0.954730 0.499 954.734
2 0.971300 0.354 971.303
0.987871 0.210 987.872
1 0.993935 0.158 993.936
1.000000 0.107 1000.000
The native vertical resolution of GEOS–3 meteorological fields is 48 pure sigma levels, extending from surface pressure up to 0.01 hPa.
In order to minimize the amount of memory required to run GEOS–CHEM, users may select to run with a reduced vertical resolution of 30 sigma levels. For the reduced vertical resolution, sigma levels above ~85 hPa are lumped together online.
Altitudes and pressures listed below were computed assuming a surface pressure of 1000 hPa.
GEOS–3 Native Vertical Grid (48 sigma layers)
L Sig Edge Sig Mid Altitude Pressure
(unitless) (unitless) (km) (hPa)
========================================================
0.000000 80.581 0.010
48 0.000009 76.733 0.019
0.000018 74.274 0.028
47 0.000033 71.412 0.043
0.000048 69.354 0.057
46 0.000070 67.056 0.080
0.000092 65.292 0.102
45 0.000123 63.332 0.133
0.000155 61.769 0.165
44 0.000200 59.972 0.210
0.000245 58.513 0.255
43 0.000308 56.854 0.317
0.000370 55.488 0.380
42 0.000455 53.948 0.465
0.000540 52.665 0.550
41 0.000653 51.241 0.662
0.000765 50.040 0.775
40 0.000913 48.709 0.922
0.001060 47.577 1.070
39 0.001250 46.332 1.260
0.001440 45.267 1.450
38 0.001670 44.153 1.680
0.001900 43.187 1.910
37 0.002215 42.043 2.225
0.002530 41.056 2.540
36 0.002915 40.009 2.925
0.003300 39.098 3.310
35 0.003790 38.087 3.800
0.004280 37.204 4.290
34 0.004890 36.243 4.900
0.005500 35.400 5.510
33 0.006270 34.467 6.280
0.007040 33.649 7.050
32 0.008008 32.745 8.017
0.008975 31.950 8.985
31 0.010190 31.072 10.200
0.011405 30.299 11.415
30 0.012943 29.438 12.952
0.014480 28.679 14.490
29 0.016430 27.831 16.440
0.018380 27.083 18.390
28 0.020855 26.248 20.865
0.023330 25.511 23.340
27 0.026465 24.688 26.475
0.029600 23.963 29.610
26 0.033570 23.151 33.580
0.037540 22.435 37.550
25 0.042575 21.633 42.585
0.047610 20.923 47.620
24 0.053980 20.129 53.989
0.060350 19.426 60.359
23 0.068415 18.637 68.424
0.076480 17.937 76.489
22 0.086690 17.151 86.699
0.096900 16.451 96.909
21 0.109790 15.666 109.799
0.122680 14.965 122.689
20 0.138840 14.182 138.849
0.155000 13.481 155.008
19 0.174820 12.710 174.828
0.194640 12.017 194.648
18 0.218295 11.270 218.303
0.241950 10.593 241.958
17 0.269500 9.876 269.507
0.297050 9.222 297.057
16 0.328275 8.541 328.282
0.359500 7.915 359.506
15 0.393650 7.281 393.656
0.427800 6.691 427.806
14 0.463900 6.110 463.905
0.500000 5.565 500.005
13 0.537050 5.038 537.055
0.574100 4.539 574.104
12 0.610850 4.070 610.854
0.647600 3.622 647.604
11 0.682900 3.211 682.903
0.718200 2.816 718.203
10 0.750600 2.467 750.602
0.783000 2.129 783.002
9 0.811000 1.846 811.002
0.839000 1.570 839.002
8 0.861500 1.353 861.501
0.884000 1.141 884.001
7 0.901750 0.976 901.751
0.919500 0.814 919.501
6 0.933150 0.691 933.151
0.946800 0.569 946.801
5 0.956950 0.479 956.950
0.967100 0.390 967.100
4 0.974300 0.328 974.300
0.981500 0.265 981.500
3 0.986350 0.223 986.350
0.991200 0.182 991.200
2 0.994148 0.156 994.148
0.997095 0.131 997.095
1 0.998548 0.119 998.548
1.000000 0.107 1000.000
GEOS–3 Reduced Vertical Grid (30 sigma layers)
L Sig Edge Sig Mid Altitude Pressure
(unitless) (unitless) (km) (hPa)
========================================================
0.000000 80.581 0.010
30 0.000078 66.394 0.087
0.000155 61.769 0.165
29 0.000460 53.866 0.470
0.000765 50.040 0.775
28 0.001647 44.255 1.657
0.002530 41.056 2.540
27 0.004785 36.399 4.795
0.007040 33.649 7.050
26 0.012710 29.561 12.720
0.018380 27.083 18.390
25 0.023990 25.329 24.000
0.029600 23.963 29.610
24 0.038605 22.256 38.615
0.047610 20.923 47.620
23 0.062045 19.252 62.054
0.076480 17.937 76.489
22 0.086690 17.151 86.699
0.096900 16.451 96.909
21 0.109790 15.666 109.799
0.122680 14.965 122.689
20 0.138840 14.182 138.849
0.155000 13.481 155.008
19 0.174820 12.710 174.828
0.194640 12.017 194.648
18 0.218295 11.270 218.303
0.241950 10.593 241.958
17 0.269500 9.876 269.507
0.297050 9.222 297.057
16 0.328275 8.541 328.282
0.359500 7.915 359.506
15 0.393650 7.281 393.656
0.427800 6.691 427.806
14 0.463900 6.110 463.905
0.500000 5.565 500.005
13 0.537050 5.038 537.055
0.574100 4.539 574.104
12 0.610850 4.070 610.854
0.647600 3.622 647.604
11 0.682900 3.211 682.903
0.718200 2.816 718.203
10 0.750600 2.467 750.602
0.783000 2.129 783.002
9 0.811000 1.846 811.002
0.839000 1.570 839.002
8 0.861500 1.353 861.501
0.884000 1.141 884.001
7 0.901750 0.976 901.751
0.919500 0.814 919.501
6 0.933150 0.691 933.151
0.946800 0.569 946.801
5 0.956950 0.479 956.950
0.967100 0.390 967.100
4 0.974300 0.328 974.300
0.981500 0.265 981.500
3 0.986350 0.223 986.350
0.991200 0.182 991.200
2 0.994148 0.156 994.148
0.997095 0.131 997.095
1 0.998548 0.119 998.548
1.000000 0.107 1000.000
The native vertical resolution of GEOS–4 meteorological fields is 55 hybrid eta levels, extending from the surface up to 0.01 hPa. The first 14 levels from the surface upward are pure sigma levels; the rest are fixed pressure levels.
In order to minimize the amount of memory required to run GEOS–CHEM, users may select to run with a reduced vertical resolution of 30 eta levels. For the reduced vertical resolution, eta levels above ~50 hPa are lumped together online.
Altitudes and pressures listed below were computed assuming a surface pressure of 1000 hPa.
GEOS-4 Native Vertical Grid (55 hybrid pressure-sigma levels)
L Eta Edge Eta Mid Altitude Pressure
(unitless) (unitless) (km) (hPa)
=======================================================
0.000000 80.581 0.010
55 0.000005 78.146 0.015
0.000010 76.357 0.020
54 0.000016 74.594 0.026
0.000023 73.180 0.033
53 0.000030 71.812 0.040
0.000038 70.657 0.048
52 0.000047 69.440 0.057
0.000056 68.392 0.066
51 0.000068 67.243 0.078
0.000079 66.245 0.089
50 0.000095 65.115 0.105
0.000110 64.130 0.120
49 0.000130 63.004 0.140
0.000149 62.021 0.159
48 0.000175 60.902 0.185
0.000201 59.924 0.211
47 0.000235 58.816 0.245
0.000269 57.846 0.279
46 0.000312 56.752 0.322
0.000355 55.794 0.365
45 0.000410 54.717 0.420
0.000466 53.773 0.476
44 0.000536 52.716 0.546
0.000607 51.788 0.617
43 0.000696 50.754 0.706
0.000785 49.844 0.795
42 0.000897 48.835 0.907
0.001009 47.946 1.019
41 0.001150 46.962 1.160
0.001291 46.092 1.301
40 0.001466 45.134 1.476
0.001641 44.286 1.651
39 0.001858 43.355 1.868
0.002075 42.529 2.085
38 0.002343 41.627 2.353
0.002610 40.825 2.620
37 0.002938 39.951 2.948
0.003266 39.173 3.276
36 0.003667 38.328 3.677
0.004067 37.574 4.077
35 0.004552 36.759 4.562
0.005037 36.030 5.047
34 0.005622 35.244 5.632
0.006207 34.539 6.217
33 0.006908 33.782 6.918
0.007610 33.101 7.620
32 0.008446 32.372 8.456
0.009283 31.716 9.293
31 0.010275 31.015 10.285
0.011267 30.383 11.277
30 0.012450 29.701 12.460
0.013634 29.085 13.643
29 0.015040 28.423 15.050
0.016447 27.824 16.457
28 0.018114 27.180 18.124
0.019782 26.596 19.792
27 0.021751 25.971 21.761
0.023721 25.402 23.730
26 0.026039 24.794 26.049
0.028358 24.240 28.368
25 0.031079 23.648 31.089
0.033800 23.108 33.810
24 0.036983 22.531 36.993
0.040166 22.004 40.175
23 0.043900 21.438 43.910
0.047634 20.920 47.644
22 0.052006 20.364 52.016
0.056379 19.855 56.388
21 0.061486 19.309 61.496
0.066594 18.807 66.603
20 0.072549 18.269 72.558
0.078503 17.773 78.512
19 0.085430 17.243 85.439
0.092357 16.753 92.366
18 0.100506 16.222 100.515
0.108655 15.731 108.663
17 0.118241 15.198 118.250
0.127828 14.706 127.837
16 0.139106 14.170 139.115
0.150385 13.674 150.393
15 0.163653 13.134 163.661
0.176922 12.633 176.930
14 0.192533 12.087 192.541
0.208144 11.581 208.152
13 0.226506 11.028 226.514
0.244867 10.514 244.875
12 0.266472 9.952 266.479
0.288076 9.429 288.083
11 0.313492 8.856 313.499
0.338908 8.322 338.915
10 0.368810 7.737 368.816
0.398712 7.191 398.718
9 0.433887 6.591 433.893
0.469063 6.030 469.068
8 0.510451 5.413 510.456
0.551839 4.835 551.843
7 0.600520 4.199 600.524
0.649201 3.603 649.204
6 0.696790 3.054 696.793
0.744379 2.533 744.382
5 0.787698 2.081 787.700
0.831017 1.648 831.018
4 0.867156 1.299 867.157
0.903295 0.962 903.296
3 0.929645 0.722 929.645
0.955994 0.488 955.995
2 0.970552 0.360 970.552
0.985110 0.234 985.110
1 0.992555 0.170 992.555
1.000000 0.107 1000.000
GEOS–4 Reduced Vertical Grid (30 hybrid pressure-sigma layers)
L Sig Edge Sig Mid Altitude Pressure
(unitless) (unitless) (km) (hPa)
========================================================
0.000000 80.581 0.010
30 0.000028 72.180 0.038
0.000056 68.392 0.066
29 0.000129 63.053 0.139
0.000201 59.924 0.211
28 0.000404 54.834 0.414
0.000607 51.788 0.617
27 0.001124 47.135 1.134
0.001641 44.286 1.651
26 0.002854 40.166 2.864
0.004067 37.574 4.077
25 0.006675 34.024 6.685
0.009283 31.716 9.293
24 0.014532 28.654 14.542
0.019782 26.596 19.792
23 0.024070 25.307 24.080
0.028358 24.240 28.368
22 0.034262 23.020 34.272
0.040166 22.004 40.175
21 0.048272 20.836 48.282
0.056379 19.855 56.388
20 0.067441 18.727 67.450
0.078503 17.773 78.512
19 0.085430 17.243 85.439
0.092357 16.753 92.366
18 0.100506 16.222 100.515
0.108655 15.731 108.663
17 0.118241 15.198 118.250
0.127828 14.706 127.837
16 0.139106 14.170 139.115
0.150385 13.674 150.393
15 0.163653 13.134 163.661
0.176922 12.633 176.930
14 0.192533 12.087 192.541
0.208144 11.581 208.152
13 0.226506 11.028 226.514
0.244867 10.514 244.875
12 0.266472 9.952 266.479
0.288076 9.429 288.083
11 0.313492 8.856 313.499
0.338908 8.322 338.915
10 0.368810 7.737 368.816
0.398712 7.191 398.718
9 0.433887 6.591 433.893
0.469063 6.030 469.068
8 0.510451 5.413 510.456
0.551839 4.835 551.843
7 0.600520 4.199 600.524
0.649201 3.603 649.204
6 0.696790 3.054 696.793
0.744379 2.533 744.382
5 0.787698 2.081 787.700
0.831017 1.648 831.018
4 0.867156 1.299 867.157
0.903295 0.962 903.296
3 0.929645 0.722 929.645
0.955994 0.488 955.995
2 0.970552 0.360 970.552
0.985110 0.234 985.110
1 0.992555 0.170 992.555
1.000000 0.107 1000.000