Welcome to IsoGSM (ver.1) data page

NEWS! IsoGSM source code is available through G-RSM.
It runs with a PC!! Please try.



  • Simulation for 2008 has been completed. -- 2009-01-12 (Mon) 23:56:14
  • Data server has been down. It'll take for a while to recover this. Sorry for this inconvenience. -- kei 2009-03-09 (Mon) 07:58:07
  • Variables list is available at here and here -- 2009-03-19 (Thu) 17:39:58
  • [Bug] Diagnosed cloud cover (all, high, middle, and low) is erroneous. Please do not use these variables. -- 2009-03-19 (Thu) 17:41:43
  • A "free-run" simulation for 1979 to 2008 is uploaded. -- kei 2009-07-08 (Wed) 06:42:12
  • "IsoGSM1 monthly time series visualizer" has been made!! Please try it at here -- kei 2009-07-29 (Wed) 11:11:38
  • A paper using the data was published on Science. See here. -- kei 2009-10-22 (Thu) 09:22:13
  • A paper using the data was published on JGR-A. See here -- kei 2009-10-26 (Mon) 00:58:33
  • Simulation for 2009 bas been completed. -- kei 2010-03-21 (Sun) 16:04:09
  • IsoGSM is now available from Scripps CVS. See http://g-rsm.wikispaces.com/Isotope+and+Water+Vapor+Tracer for detail. -- kei 2010-06-24 (Thu) 03:43:33

What is the IsoGSM data?

IsoGSM data is first multi-decadal global 3D isotope (HDO, H218O) simulation data, which are consistent to the well-known global "quasi-observational" data, Reanalysis data (particularly NCEP/DOE Reanalysis; Kanamitsu et al., 2002 BAMS).

The detailed document is available on:

Yoshimura, K., M. Kanamitsu, D. Noone, and T. Oki (2008), Historical Isotope Simulation using Reanalysis Atmospheric Data, J. Geophys. Res., 113, D19108, doi:10.1029/2008JD010074.

Terms and Conditions

A user must agree to following terms and conditions before usage.

These data (IsoGSM data hereafter) are made freely available to the public and the scientific community in the belief that their wide dissemination will lead to greater understanding and new scientific insights. The availability of IsoGSM data does not constitute publication of the data. We rely on the ethics and integrity of the user to assure that Kei Yoshimura (KY hereafter) receives fair credit for our work. If IsoGSM data are obtained for potential use in a publication or presentation, KY should be informed at the outset of the nature of this work. If IsoGSM data are essential to the work, or if an important result or conclusion depends on the data, co-authorship may be appropriate. This should be discussed at an early stage in the work. Manuscripts using IsoGSM data should be sent to KY for review before they are submitted for publication so that it can be insured that the quality and limitations of IsoGSM data are accurately represented.

Why is it called IsoGSM?

IsoGSM stands for Isotopes-incorporated Global Spectral Model, which was developed in Scripps Institution of Oceanography. The IsoGSM data is the simulation results from this global model with a special treatment to include the "actual" atmospheric thermodynamic situations, namely the spectral nudging technique.

What does the IsoGSM data contain?

IsoGSM data consist of:

  • 3D distribution of isotopic ratios in water vapor
  • 2D distribution of isotopic ratios in precipitation
  • 2D distribution of isotopic ratios in evaporation
  • 2D distribution of isotopic ratios in surface soil moisture

in horizontally about 200 km (T62) scale, vertically 17 levels, and 6-hourly for 1979-2007. The non-isotopic variables are also available (i.e., temperature, wind speed, humidity, radiation, surface pressure, etc.etc.)

The variable lists (GrADS control files) are available at:

What is good in the IsoGSM data?

The isotopic ratios in water vapor (and consequently precipitation and evaporation) are reasonably well agreed with the reality. It means that you can compare your observed isotopic ratios in precipitation and/or vapor, or you can use the IsoGSM data for reference or input values for your purposes.

Again, the data are very consistent with the actual meteorological situations in a 6-hourly resolution, so that the IsoGSM data can be helpful for analysis of in-situ observation for isotopes.

How to obtain the IsoGSM data?

  • fuyu.ucsd.edu is decommissioned. The data is now accessible through different channel. Send me an email.

The data are obtainable online. Users can access the data server (fuyu.ucsd.edu) as user "dataman". Email us to get the password. "dataman" is allowed to access the server by sftp only. $ sftp dataman@fuyu.ucsd.edu > cd IsoGSM1

Please contact Kei Yoshimura (k1yoshimura[at]ucsd.edu) for registration with your IP address so he can add it to the whitelist of the firewall. Your IP address has to be a static one from the institution you work for, and it has to be registered with DNS servers. Please check with your system administrator before contacting us. A dynamic IP from Internet service providers cannot be accepted for security reasons. Please email us if you have any questions.

File/Directory description

  • Storage structure
            /flx_mon-s1.ctl         -- monthly flx data ctlfile 
            /pgb_mon-s1.ctl         -- monthly pgb data ctlfile
            /IsoGSMmon_s1.ctl       -- monthly P,E,W data ctlfile
            /IsoGSMmon_s1_clim.ctl  -- monthly climatology data (P,E,W) ctlfile 
            /IsoGSMmon_s1_clim.dat  -- monthly climatology datafile
    /IsoGSM1/gYYYYiso-s1            -- yearly directories
                        /flx.ctl              -- 6-hourly flx data ctlfile 
                        /flx.ftXX             -- 6-hourly flx datafile
                        /flxmon.s1.YYYY.grd   -- monthly flx datafile
                        /pgb.ctl              -- 6-hourly pgb data ctlfile
                        /pgb.ftXX             -- 6-hourly pgb datafile
                        /pgbmon.s1.YYYY.grd   -- monthly pgb datafile
                        /sig.ftXX             -- sigma-level raw data
                        /sfc.ftXX             -- surface raw data
                        /sigit, sigitdt, sfci -- restart files
  • gYYYYiso-s1: includes data files for year YYYY.
  • flxmon.s1.YYYY.grd: monthly average of 2D variables. Big-endian 4byte binary. flx_mon-s1.ctl is the GrADS control file for these files.
  • pgbmon.s1.YYYY.grd: monthly average of 3D variables (some 2D included). Big-endian 4byte binary. pgb_mon-s1.ctl is the GrADS control file for these files.
  • IsoGSMmon_s1_YYYY.dat: monthly averages for TPW, P, and E for H2O, d18O, dD. GrADS control file is IsoGSMmon_s1.ctl.
  • flx.ftXX and pgb.ftXX: 6-hourly output for 2D and 3D, respectively. GRIB format. Can be read/visualized by flx.ctl and pgb.ctl.
  • Please see each control file for details of the data contents.

Getting started

  1. Obtain IsoGSMmon_s1.ctl and IsoGSMmon_s1_1979.dat
    $ sftp dataman@fuyu.ucsd.edu
    > cd IsoGSM1
    > get IsoGSMmon_s1.ctl
    > lmkdir g1979iso-s1
    > lcd g1979iso-s1
    > cd g1979iso-s1
    > get IsoGSMmon_s1_1979.dat
    > quit
  2. Open GrADS and visualize some fields.
    $ grads
    > open IsoGSMmon_s1.ctl
    > set gxout shaded
    > d po
      precipitation d18O is shown
    > d qd
      TPW (total column vapor) dD is shown
    > c
    > set gxout scatter
    > d q;qo
      relation b/w TPW and TPWd18O is shown (clear Rayleigh curve)

About the data in detail

Unit in flx files (flx.ftXX or flxmon.s1.YYYY.grd)

All of the isotopic variables except surface reservoir (RRESV1(ID=94), RRESV2(ID=95)) have unit of flux or status of H2O divided SMOW's H218O or HDO amount.

CPRATsfc  0 214,1,0  ** surface Convective precip. rate [kg/m^2/s]
CPRAT1  0 69,1,0  ** cprat H218O [kg/m^2/s/SMOW]
CPRAT2  0 70,1,0  ** cprat HDO [kg/m^2/s/SMOW]
LHTFLsfc  0 121,1,0  ** surface Latent heat flux [W/m^2]
LHTFL1  0 119,1,0  ** surface Latent heat flux H218O [W/m^2/SMOW]
LHTFL2  0 120,1,0  ** surface Latent heat flux HDO [W/m^2/SMOW]
PRATEsfc  0 59,1,0  ** surface Precipitation rate [kg/m^2/s]
PRATE1  0 67,1,0  ** prate H218O [kg/m^2/s/SMOW]
PRATE2  0 68,1,0  ** prate HDO [kg/m^2/s/SMOW]
PWATclm  0 54,200,0 ** atmos column Precipitable water [kg/m^2]
PWAT1  0 150,200,0 ** atmos column Precipitable water H218O [kg/m^2/SMOW]
PWAT2  0 151,200,0 ** atmos column Precipitable water HDO [kg/m^2/SMOW]
RRESV1   0 94,1,0 ** surface reservoir H218O ratio [ratio]
RRESV2   0 95,1,0 ** surface reservoir HDO ratio [ratio]

For example, precipitation HDO (prate2(ID=68)) has unit of [kg/m^2/SMOW]. Therefore, the isotopic ratio in delta value (dD) in precipitation is calculated by (prate2/pratesfc-1)*1000

Unit in pgb files (pgb.ftXX or pgbmon.s1.YYYY.grd)

In pgb.ftXX files, those fields below are isotope-related.

SPFH      17 51,100,0 Specific humidity (kg/kg)
TR2     17 153,100,0 H218O mixing ratio (kg/kg/SMOW)
TR3      17 152,100,0 HDO mixing ratio (kg/kg/SMOW)
PWAT       0 54,200,0 Precipitable water (kg/m**2)
TR2V       0 76,200,0 H218O column amount (kg/m**2/SMOW)
TR3V       0 77,200,0 HDO column amount (kg/m**2/SMOW)

TR2 is H218O, and TR3 is HDO for 3D. TR2V and TR3V are column integration (2D). The units are kg/kg/SMOW for TR2 and TR3, and kg/m**2/SMOW for TR2V and TR3V. TR2/SPFH becomes the isotopic ratio (H218O) toward SMOW. Therefore the isotopic ratio in delta form in permil unit would be (TR2/SPFH-1)*1000 for d18O in vapor.

Similarly for column vapor, (TR3V/PWAT-1)*1000 denotes the delta-D.

NetCDF version

Monthly data in NetCDF format is available in IsoGSM1/nc directory.

sftp dataman@fuyu.ucsd.edu:/IsoGSM1/nc 

In this format, "sfc" and "atm" files correspond with "flx" and "pgb" files in Grib format.

List of papers that use the IsoGSM data (accepted only)

  • Uemura, R., Y. Matsui, K. Yoshimura, H. Motoyama, N. Yoshida, Evidence of deuterium excess in water vapour as an indicator of ocean surface conditions, J. Geophys. Res., 113, doi:1029.10/2008JD010209, 2008.
  • Abe, O., S. Agata, M. Morimoto, M. Abe, K. Yoshimura, T. Hiyama, and N. Yoshida, A 6.5-year continuous record of sea surface salinity and seawater isotopic composition at Harbor of Ishigaki Island, southwest Japan, Isotopes in Environmental and Health Studies, 45, 247-258, 2009.
  • Frankenberg, C., K. Yoshimura, T. Warneke, I. Aben, A. Butz, N. Deutscher, D. Griffith, F. Hase, J. Notholt, M. Schneider, H. Schrijver, T. Röckmann: Dynamic processes governing lower-tropospheric HDO/H2O ratios as observed from space and ground, Science, 325, 1374-1377, 2009.
  • Pfahl, S., and H. Wernli, Lagrangian simulations of stable isotopes in water vapor: An evaluation of nonequilibrium fractionation in the Craig-Gordon model, J. Geophys. Res., 114, D20108, doi:10.1029/2009JD012054, 2009.
  • Schneider, M., Yoshimura, K., Hase, F., and Blumenstock, T.: The ground-based FTIR network's potential for investigating the atmospheric water cycle, Atmos. Chem. Phys., 10, 3427-3442, doi:10.5194/acp-10-3427-2010, 2010.
  • Galewsky, J., and J. V. Hurley, An advection-condensation model for subtropical water vapor isotopic ratios, J. Geophys. Res., 115, doi:10.1029/2009JD013651, 2010. in press.
  • Yoshimura, K., M. Kanamitsu, and M. Dettinger, Regional downscaling for stable water isotopes: A case study of an Atmospheric River event, J. Geophys. Res., 115, doi:10.1029/2010JD014032, 2010. in press.