Difference between revisions of "Soil NOx emissions"
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== Known issues == | == Known issues == | ||
| − | === Dependency between | + | === Dependency between soil NOx emissions and dry deposition === |
In GEOS-Chem there is a code dependency between the [[Dry deposition|dry deposition routines]] and the soil NOx emissions routines. This is purely historical baggage that goes back to the days of the old 9-layer Harvard-GISS CTM (from which these routines were taken). | In GEOS-Chem there is a code dependency between the [[Dry deposition|dry deposition routines]] and the soil NOx emissions routines. This is purely historical baggage that goes back to the days of the old 9-layer Harvard-GISS CTM (from which these routines were taken). | ||
Revision as of 15:41, 19 February 2010
NOTE: Page under construction!
Contents
Overview
Modifications
Validation
References
- Yienger, J.J, and H. Levy, Empirical model of global soil-biogenic NOx emissions, J. Geophys. Res., 100, D6, 11,447-11464, June 20, 1995.
- Wang, Y., D.J. Jacob, and J.A. Logan, Global Simulation of tropospheric O3-NOx-hydrocarbon chemistry: 1. Model formulation, J. Geophys. Res., 103, pp. 10713-10725, 1998.
--Bob Y. 16:37, 17 February 2010 (EST)
Known issues
Dependency between soil NOx emissions and dry deposition
In GEOS-Chem there is a code dependency between the dry deposition routines and the soil NOx emissions routines. This is purely historical baggage that goes back to the days of the old 9-layer Harvard-GISS CTM (from which these routines were taken).
Please see the full discussion on the dry deposition wiki page.
--Bob Y. 10:41, 19 February 2010 (EST)
Quantities zeroed at startup
The existing GEOS-Chem soil NOx emissions code zeroes several quantities at startup, among which are the soil pulsing factors. These are the multiplicative factors which compute the sudden increase (or "pulse") of NOx from soils after precipitation falls on dry soil. There are factors for 3 pulsing types in the code: after 5 days, after 10 days, and after 15 days. These are stored in the SOILPULS array, along with a flag to denote dry or wet soil.
Here is an illustration of the problem. The soil pulsing and resultant quantities for a run that started on Feb 1, 2000 are printed out below.
---> DATE: 2000/02/01 GMT: 00:00 X-HRS: 0.000 ###---------------------------------------------------- ### I, J : 69 51 ### SOILPULS 1 : 1.00000000000000 ! dry/wet soil ### SOILPULS 2 : 0.000000000000000E+000 ! 5-day pulsing factor ### SOILPULS 3 : 0.000000000000000E+000 ! 10-day pulsing factor ### SOILPULS 4 : 0.000000000000000E+000 ! 15-day pulsing factor ### PULSE : 1.00000000000000 ! Resultant pulsing factor ### SOIL TOT : 11112048160.8142 ! Soil NOx emissions @ box (69,51)
Note that all of the soil pulsing factors are zero because this is the very first timestep of the run. However, if we compare this to a run which started on Jan 1, 2000:
---> DATE: 2000/02/01 GMT: 00:00 X-HRS: 744.000 ###---------------------------------------------------- ### I, J : 69 51 ### SOILPULS 1 : 1.00000000000000 ! dry/wet soil flag ### SOILPULS 2 : 2.843218125816628E-003 ! 5-day pulsing factor ### SOILPULS 3 : 2.189570703768949E-002 ! 10-day pulsing factor ### SOILPULS 4 : 4.879111537477707E-002 ! 15-day pulsing factor ### PULSE : 1.89150985108935 ! Resultant pulsing factor ### SOIL TOT : 21018548561.9593 ! Soil NOx emissions @ box (69,51)
we see that the soil pulsing factors have already been initialized to non-zero values from the January spinup. This leads to different soil NOx emissions than in the run which started on Feb 1, 2000. This is an inherent flaw in the design of the original soil NOx code, which was taken from the old Harvard-GISS CTM.
Rynda Hudman is currently working on updating the soil NOx algorithm. The pulsing information (as well as other quantities) will be stored in a soil NOx restart file. This will eliminate the problem.
--Bob Y. 10:49, 18 February 2010 (EST)
