Wet deposition

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NOTE: Page under construction!



  1. Selin, N.E. and D.J. Jacob, Seasonal and spatial patterns of mercury wet deposition in the United States: North American vs. intercontinental sources, Atmospheric Environment, 42, 5193-5204, 2008. PDF
  2. Liu, H., D.J. Jacob, I. Bey, and R.M. Yantosca, Constraints from 210Pb and 7Be on wet deposition and transport in a global three-dimensional chemical tracer model driven by assimilated meteorological fields, J. Geophys. Res., 106, 12,109-12,128, 2001. PDF

Known issues

Negative tracer in routine WETDEP because of negative RH

See this post: GEOS-5 issues#Small negative RH value in 20060206.a6.2x25 file

Fixes are available at ftp://ftp.as.harvard.edu/pub/geos-chem/patches/v8-01-01.

--phs 16:31, 6 June 2008 (EDT)

Negative tracer in routine WETDEP

Dylan Millet wrote:

I'm having a run die consistently at the same time (October 1, 2005; first time step of the month) in large-scale wetdep, with an STT element < 0.
  • Platform: Linux cluster
  • Threads: 8
  • Version: v7-4-13 out of the box.
  • GEOS4, 4x5, 30L, full chemistry
  • IFORT 10.1
In Section 6 (No Downward Precip) of wetscav_mod.f, subroutine safety is getting called.
    WETDEP - STT < 0 at    1   1  29 for tracer    7 in area    6
(First of all it seems odd to do wetdep for L=29, this is 63 km up). Have you seen anything like this? I ran for the whole year starting Jan 1 successfully until this point.
... By the way, the problem persists when I turn off chemistry altogether.

Philippe Le Sager replied:

I used your restart file and the same input.geos (w/ chemistry on and off). My code went thru without problem. I tried both Sun Studio and Ifort 9 compilers, and the later on two different machines (altix and ceres). I used v7-04-13 and v8-01-01. I never reproduced your error.
We just got the new Ifort 10, and tried it too. I run v8-01-01 without an error. But when I tried v7-04-13, I finally reproduced your error, with the exact same negative values!
In other words: the bug happens with IFort 10 and v7-04-13 only.
Also, have a look at this recent development. This is not the reason for your bug (I tried v8 w/ ifort 10 and isorropia -like v7-04-13- and it did not crash), but using RPMARES instead of Isorropia may be a way to fix it.
... More about the Ifort 10 / v7-04-13 issue. When I wanted to debug with TotalView, I could not reproduce the bug anymore.... because I simply suppress any optimization. So, I did more test and found that if the default -O2 optimization is used, GEOS-Chem crashes. But it works fine with -O1. It is hard to tell what happens, since only the emissions step is done between reading the restart file and the crash.
Bob and I will further test Ifort 10 for optimization on our machines. Maybe we will find something... For the time being, you may have to switch to -O1, at least for the run that crashes. You will find the optimization flag at the beginning of the Makefile.ifort.

Long story short: This appears to be an optimization issue with IFORT 10 and v7-04-13. Upgrading to GEOS-Chem v8-01-01 should solve this problem.

--Bmy 10:38, 17 April 2008 (EDT)