Last updated: 2008-03-18 by David Stepaniak (davestep@ucar.edu)\s\s\s\s\s\s\s\s\s\s\s\s\s\s\s\s\s\s\s\s\sBack to Documentation
Presented are calculations of model full level hybrid 'A' and 'B' coefficients for JRA-25 using energy and angular momentum conserving vertical finite-difference scheme (equation 3.18 Simmons and Burridge, 1981), JMA JRA-25 'A' and 'B' coefficients at model interface levels (given), and linear regression over a range of surface pressures (2,000 to 102,000 Pa). Exceptions are full model levels 1 and 40 for which information at model interface levels 1 and 2, and 40 and 41, respectiveley, were averaged to obtain agreement with results reported by JMA.
Example pressures shown are for model full levels using the 'A' and 'B' coefficients in columns 3 and 4, a surface pressure (PS) of 100,000 Pa, and the relation p = A + B*PS.
It is recommended that the 'A' and 'B' coefficients in columns 3 and 4 are used for JRA-25 model vertical coordinate calculations.
Acronyms:
A: Hybrid vertical coordinate 'A' coefficient in Pascals
B: Hybrid vertical coordinate 'B' coefficient, no dimension
DSS: Data Support Section, NCAR
JMA: Japan Meteorological Agency
JMA DOC: Definition of vertical levels of the model used in JRA-25 and JCDAS, and Onogi et al. (2007)
JRA-25: Japanese 25-year ReAnalysis
MIL: Model interface level
MFL: Model full level
PS: Surface pressure in Pascals
SB318: Simmons and Burridge (1981) equation 3.18
References:
Simmons, A.J., and D.M. Burridge, 1981: An energy and angular-momentum conserving
vertical finite-difference scheme and hybrid vertical coordinates. Mon. Wea. Rev.,
109, 405-412.
Onogi, K., J. Tsutsui, H. Koide, M. Sakamoto, S. Kobayashi, H. Hatsushika, T. Matsumoto,
N. Yamazaki, H. Kamahori, K. Takahashi, S. Kadokura, K. Wada, K. Kato, R. Oyama, T. Ose,
N. Mannoji, and R. Taira, 2007: The JRA-25 Reanalysis. J. Met. Soc. Jap., 85(3), 369-432.
NOTE: JRA-25 model levels are ordered 1 to 40, from lowest model altitude
to highest model altitude in the atmosphere.
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'A' coef 'B' coef Pressure Pressure ( Pressure
Model Model MIL: JMA DOC MIL: JMA DOC at MFL, PS= at MFL, PS= at MFL, PS=
Interface Full MFL: DSS + MFL: DSS + 100,000 Pa, 100,000 Pa, 100,000 Pa,
Level Level SB318 SB318 DSS + SB318 JMA DOC averaging only
(MIL) (MFL) (in Pascals) (no dimension) (Pascals) (Pascals) (Pascals) )
---41-------------- 0.0000------ 0.000000------------------------------------------------ TOA
40 40.0000 0.000000 40.0 40.0 ( 40.0)
---40-------------- 80.0000------ 0.000000------------------------------------------------
39 111.3629 0.000000 111.4 111.0 ( 113.0)
---39-------------- 146.0000------ 0.000000------------------------------------------------
38 198.4496 0.000000 198.4 198.0 ( 201.0)
---38-------------- 256.0000------ 0.000000------------------------------------------------
37 340.6550 0.000000 340.7 341.0 ( 344.5)
---37-------------- 433.0000------ 0.000000------------------------------------------------
36 565.8327 0.000000 565.8 566.0 ( 571.5)
---36-------------- 710.0000------ 0.000000------------------------------------------------
35 907.2600 0.000000 907.3 907.0 ( 915.0)
---35-------------- 1120.0000------ 0.000000------------------------------------------------
34 1399.9662 0.000000 1400.0 1400.0 ( 1410.0)
---34-------------- 1700.0000------ 0.000000------------------------------------------------
33 2087.2001 0.000000 2087.2 2087.0 ( 2100.0)
---33-------------- 2500.0000------ 0.000000------------------------------------------------
32 3000.2446 0.000000 3000.2 3000.0 ( 3015.0)
---32-------------- 3529.9999------ 0.000000------------------------------------------------
31 4153.5445 0.000000 4153.5 4154.0 ( 4170.0)
---31-------------- 4809.9998------ 0.000000------------------------------------------------
30 5520.7659 0.000175 5538.3 5538.0 ( 5555.0)
---30-------------- 6263.4430------ 0.000366------------------------------------------------
29 6926.1895 0.002070 7133.2 7133.0 ( 7150.0)
---29-------------- 7610.5057------ 0.003895------------------------------------------------
28 8216.1823 0.007171 8933.3 8933.0 ( 8950.0)
---28-------------- 8836.3998------ 0.010636------------------------------------------------
27 9357.7751 0.015757 10933.5 10933.0 (10950.0)
---27-------------- 9887.6595------ 0.021123------------------------------------------------
26 10307.0069 0.028267 13133.7 13133.0 (13150.0)
---26-------------- 10729.9492------ 0.035701------------------------------------------------
25 11037.4583 0.044964 15533.9 15533.0 (15550.0)
---25-------------- 11344.7090------ 0.054553------------------------------------------------
24 11536.9453 0.065971 18134.0 18133.0 (18150.0)
---24-------------- 11725.9979------ 0.077740------------------------------------------------
23 11804.5346 0.091297 20934.2 20933.0 (20950.0)
---23-------------- 11877.7374------ 0.105223------------------------------------------------
22 11847.9784 0.120864 23934.3 23933.0 (23950.0)
---22-------------- 11811.3609------ 0.136886------------------------------------------------
21 11681.5551 0.154529 27134.4 27133.0 (27150.0)
---21-------------- 11543.8545------ 0.172561------------------------------------------------
20 11324.2794 0.192103 30534.6 30533.0 (30550.0)
---20-------------- 11096.1449------ 0.212039------------------------------------------------
19 10807.0569 0.232784 34085.4 34084.0 (34100.0)
---19-------------- 10509.4887------ 0.253905------------------------------------------------
18 10166.4428 0.275697 37736.1 37735.0 (37750.0)
---18-------------- 9815.1306------ 0.297849------------------------------------------------
17 9421.4089 0.321146 41536.0 41535.0 (41550.0)
---17-------------- 9019.2863------ 0.344807------------------------------------------------
16 8585.7562 0.369501 45535.8 45535.0 (45550.0)
---16-------------- 8143.7820------ 0.394562------------------------------------------------
15 7692.0877 0.419942 49686.3 49685.0 (49700.0)
---15-------------- 7232.3532------ 0.445676------------------------------------------------
14 6772.8006 0.471639 53936.7 53936.0 (53950.0)
---14-------------- 6305.6015------ 0.497944------------------------------------------------
13 5847.0159 0.524400 58287.0 58286.0 (58300.0)
---13-------------- 5381.1684------ 0.551188------------------------------------------------
12 4931.0929 0.578062 62737.3 62737.0 (62750.0)
---12-------------- 4474.1348------ 0.605259------------------------------------------------
11 4048.0819 0.631900 67238.1 67237.0 (67250.0)
---11-------------- 3615.8020------ 0.658842------------------------------------------------
10 3217.2407 0.685215 71738.7 71738.0 (71750.0)
---10-------------- 2813.0577------ 0.711869------------------------------------------------
9 2452.0852 0.737377 76189.8 76189.0 (76200.0)
--- 9-------------- 2086.2747------ 0.763137------------------------------------------------
8 1769.3920 0.787217 80491.1 80491.0 (80500.0)
--- 8-------------- 1448.5500------ 0.811514------------------------------------------------
7 1179.0202 0.833636 84542.7 84542.0 (84550.0)
--- 7-------------- 906.4261------ 0.855936------------------------------------------------
6 684.9204 0.875594 88244.3 88244.0 (88250.0)
--- 6-------------- 461.1954------ 0.895388------------------------------------------------
5 286.6156 0.912093 91495.9 91496.0 (91500.0)
--- 5-------------- 110.5610------ 0.928894------------------------------------------------
4 55.5043 0.941917 94247.2 94247.0 (94250.0)
--- 4-------------- 0.0000------ 0.955000------------------------------------------------
3 0.0000 0.964983 96498.3 96498.0 (96500.0)
--- 3-------------- 0.0000------ 0.975000------------------------------------------------
2 0.0000 0.982490 98249.0 98249.0 (98250.0)
--- 2-------------- 0.0000------ 0.990000------------------------------------------------
1 0.0000 0.995000 99500.0 99500.0 (99500.0)
--- 1-------------- 0.0000------ 1.000000------------------------------------------------ SURFACE