Version 2.1 IFA-averaged fields for TOGA COARE in support of Single Column Models (v2.0 released 04/26/02, v2.1 released 10/21/02)

TOGA-COARE Homepage Available TOGA-COARE Data About the Dataset Files

About the Dataset Files

Users of the version 2 datasets should reference Ciesielski et al. (2003) listed below.

The data files have been gzipped and should be transferred as binary files. This should be a setable feature of your Web Browser.

The data are contained in the following four files with version number as part of filename:

  • basic fields as a function of pressure, basic_flds.ifa
  • large-scale forcing fields as a function of pressure, lsf_flds.ifa
  • derived fields as a function of pressure, deriv_flds.ifa
  • miscellaneous fields (e.g., So, Eo, Po, Qr) , misc_flds.ifa
  • A sample fortran program is available to read the data from these files.

    All data in these files represent an average over the COARE Intensive Flux Array (IFA) computed using the gridded dataset described below. At the perimeters of the IFA polygon were four Integrated Sounding Sites (ISS): Kapingamarangi, Manus, R/V Shiyan 3 and R/V Kexue 1. The dates when the R/V ships were present are:
    cruise 1: 11/10 to 12/10
    cruise 2: 12/18 to 01/23
    cruise 3: 01/31 to 02/18
    One must realize that the representativeness of IFA averaged data is best during these three cruises and should be used with caution at other times.

    Fields of geopotential height (z), zonal wind (u), meridional wind (v), temperature (T) and specific humidity (q) were objectively analyzed using multiquadric interpolation (Nuss and Titley 1994) over the Large Scale Array (LSA) of TOGA/COARE at 25 mb resolution from 1000 to 25 mb and at 1 degree resolution in both the latitude and longitude directions. A description of this gridded data product is given in Ciesielski et al. (1997). Surface pressure (see note below) was also analyzed over the LSA. This analyses was done for 480 six hour intervals (00, 06, 12, and 18UTC) during the COARE Intensive Observing Period (IOP - 1 November, 1992 through 28 February, 1993).


    File "basic_flds.ifa" contains 480 periods of six-hourly data. For each six hour period there are 42 lines of data.
    Line 1 contains: [year, month, day, hour]
                      written with format (4i3)
    Lines 2-42 contain: [p(mb), z(m), T(C), q(g/kg), rh(%), u(m/s), v(m/s) 
                      written with format (f7.1,1x,6f8.2)
    File "deriv_flds.ifa" contains 480 periods of six-hourly data. For each six hour period there are 42 lines of data.
    Line 1 contains: [year, month, day, hour]
                      written with format (4i3)
    Lines 2-42 contain: [p(mb), divergence(1/s)*10e6, vertical p-velocity (mb/hr),
                         Q1 (K/day), Q2(K/day)]
                      written with format (f7.1,1x,4f8.2)
    The apparent heat source, Q1, and moisture sink, Q2 (Yanai et al. 1973)
    were computed as:
    Q1/cp = [dT/dt + h(T) + (p/po)**kappa * omega * d(theta)/dp]
    Q2/cp = -Lv/cp * [dq/dt + h(q) + v(q)]
          where dt = 12 hours
                po = 1000 mb
                cp = 1004
                Lv = 2.5e6
                 g = 9.8
    Note: The computation of Q1 and Q2 were not done for the first and last periods of the IOP because time center differences were used in computing these fields and no grids were analyzed before and after the IOP.
    Omega is computed using O'Brien's (1970) method with an isovalue adjustment. Omega is set to zero at the surface and at 100 mb.

    File "lsf_flds.ifa" contains 480 periods of six-hourly data. For each six hour period there are 42 lines of data.

    Line 1 contains: [year, month, day, hour]
                     written with format (4i3)
    Lines 2-42 contain: [p(mb), hT(C/s), vT(C/s), hq(gr/(gr*s)), vq(gr/(gr*s))]
                              written with format (f8.2,1p,8e11.3)
                              where hT - horizontal advection of T
                              where vT -   vertical advection of T
                              where hq - horizontal advection of q
                              where vq -   vertical advection of q
    These horizontal and vertical advection terms were computed using centered differences as follows:
    horizontal advection of "f": h(f) = u*df/dx + v*df/dy
                          where: dx = a cos(phi)*d(lambda)
                                 dy = a d(phi)
                                 phi    - latitiude
                                 lambda - longitude
    vertical advection of "f": v(f) = omega*df/dp
    File "misc_flds.ifa" contains values of IFA averaged miscellaneous data (IR brightness temperature, sea surface temperature and sensible and latent heat fluxes, budget-derived rainfall and net-radiative heating) The sensible and latent heat fluxes represent the average from several buoys in the IFA. Once surface evaporation is known, rainfall rates can be computed from the moisture budget by integrating the equation for Q2 (shown above) from 1000 mb to 100 mb as follows:
    po = eo + 1./(g*Lv) * [integral(Q2*dp) from 1000mb to 100mb]
    Line 1-478 contains: [year, month, day, hour, IFA average brightness temp (C), 
    IFA average SST(C), IFA average sensible and latent heat flux (mm/day), 
    rainfall (mm/day), net radiative heating rate (mm/day)]
                         written with format (4i3,6f8.2)
    History of dataset changes
    06/18/96 Due to very flat surface pressure (psfc) gradients over the warm pool and preceived deficiencies in the surface pressure field, the lower boundary condition was changed from
              omega = u*d(psfc)/dx + v*d(psfc)/dy
              omega = 0.
    06/18/96 Divergence and omega were corrected due to a slight error found in implementation of the O'Brien adjustment scheme.

    06/18/96 Surface winds were corrected at R/V Shiyan 3 and R/V Kexue 1. Previous winds were off by about 12 degrees.

    The 06/18/96 changes resulted in omega changes from the previous version of the analyses that were greater than 50% from the surface to 975 mb (where omegas are quite small), decreasing to less than 10% above 800 mb and to less than 1% above 500 mb.

    07/06/96 Surface fields were corrected in files fields.ifa and advect.ifa on 11/09/92 at 12UTC due to some bad data that made it into the surface analyses on this day.

    09/23/96 Date information was corrected in file misc.ifa. In the original version of the file the date associated with data at 00 UTC was incorrect.

    11/13/96 Improved surface analyses by assuming that data were from surface only if the height of the observations were within 10 m of station height. Also, bad surface humidities were removed (i.e., specific humidities less than 10 g/kg). The impact of this latter improvement will be most noteable from 11/17/92 to 01/04/93 when surface humidities at Kapinga were often considered bad (i.e., too low). The main effect of these changes, of course, are to the surface data themselves. The overall effect was to increase the IOP IFA daily averaged rainfall (estimated from the Q2 budget) from 8.166 mm/day to 8.207 mm/day (or an increase of 0.041 mm/day).

    04/16/02 The version 2.0 analysis uses the NCAR/ATD humidity corrected sonde data (Wang et al. 2002). Also, we employed a spurious divergence correction (Haertel et al. 2002). The overall effect of these corrections was to increase the IOP IFA daily averaged rainfall (estimated from the Q2 budget) to 8.40 mm/day and decreases to -.50 K/day.

    10/21/02 The version 2.1 analysis corrects the humidity variables for temperatures below freezing.


    Mapes, B. E., P. E. Ciesielski, and R. H. Johnson, 2003: Sampling errors in rawinsonde-array budgets. J. Atmos. Sci., 60, 2697-2714. [PDF]

    Ciesielski, P.E., R.H. Johnson, P.T. Haertel and J. Wang: 2003: Corrected TOGA COARE sounding humidity data: Impact on diagnosed properties of convection and climate over the warm pool. J. Clim., 16, 2370-2384. [ PDF]

    Ciesielski, P.E., L.M. Hartten, and R.H. Johnson, 1997: Impacts of merging profiler and rawinsonde winds on Toga COARE analyses. J. of Atmos. Oceanic Tech., 14, 1264-1279.

    Johnson, R.H., and P.E. Ciesielski, 2000: Rainfall and Radiative Heating Rate Estimates from TOGA-COARE Atmospheric Budgets. J. Atmos. Sci. 57, 1497-1514. [PDF]

    Lin X. and R.H. Johnson, 1996: Kinematic and thermodynamic characteristics of the flow over the westerm Pacific warm pool during TOGA COARE. J. Atmos. Sci., 53, 3367-3383.

    Miller E.R. and A.C. Riddle, 1994. TOGA COARE integrated sounding system data report - Volume IA Revised Edition. Available from the TOGA-COARE International Project Office, UCAR, P.O. Box 3000, Boulder, CO 80307.

    Nuss W.A. and D.W. Titley, 1994: Use of multiquadric interpolation for meteorological objective analysis. Mon. Wea. Rev., 22, 1611-1631.

    O'Brien J.J., 1970: Alternative solutions to the classical vertical velocity problem. J. Appl. Meteor., 9, 197-203.

    Wang, J., H.L. Cole, D.J. Carlson, E.R. Miller and K. Beierle, 2002: Corrections of humidity measurements errors from the Vaisala RS80 radiosonde -- application to TOGA COARE data. J. of Atmos. Oceanic Tech. (In press)

    Weller, R.A., and S.P.,Anderson, 1996: Surface meteorology and air-sea fluxes in the western Pacific during the TOGA COARE. J. Climate. 9, 1959-1990.

    Yanai, M.S., S. Esbensen and J.H. Chu, 1973: Determination of bulk properties of tropical cloud clusters form large-scale heat and moisture budgets. J. Atmos. Sci., 30, 611-627.

    Please send any questions or comments to Paul Ciesielski,