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MSU (Microwave Sounding Unit) Daily Troposphere Temperatures and Precipitation

Brief Description:

  • Two Microwave Sounding Unit tropospheric temperatures and daily average precipitation available in a global grid (2.5°x2.5°). More Details...

Temporal Coverage:

  • Daily values 1979/01/01 to 1993/12/31 for temperature
  • Daily values 1979/01/01 to 1996/12/31 for precipitation

Spatial Coverage:

  • 2.5 degree latitude x 2.5 degree longitude global grid (144x73)
  • 90N - 90S, 0E - 357.5E

Levels:

  • N/A

Update Schedule:

  • Static

Download/Plot Data:

Variable Statistic Level Download File Create Plot/Subset
Air Temperature Mean Channel 23 air_msu23.nc plot
Air Temperature channel 34 Mean Channel 34 air_msu34.nc plot
Precipitation Accumulation Surface precip.day.accum.nc plot
Precipitation Daily Long Term Mean Surface precip.day.ltm.nc plot
Precipitation Accumulation Surface precip.mon.mean.nc plot
Precipitation Monthly Long Term Mean Surface precip.mon.ltm.nc plot

Usage Restrictions:

  • None

Detailed Description:

  • This data set consists of two MSU tropospheric temperatures levels and precipitation which are described in detail below. The NOAA satellites contributing to this dataset are, in order of their launch, TIROS-N, NOAA-6, -7, -9,- 10,-11, and NOAA-12. NOAA-8 data were not used due to poor data quality.

    MSU Ch2/3 Daily Lower Troposphere Temperatures with Lim93 Correction

    This data set consists of 2.5 deg gridpoint fields of lower tropospheric deep layer temperatures (Ch2/3). It is a level 3 gridded product that was created from the level 2 orbit files. Data for each scan (there are 11 scan positions per scan line) have been binned according to time and space. The temporal binning is based on the Julian day with ascending and descending orbits combined. The average values are calculated from all footprints which at least partially cover the 2.5 deg by 2.5 deg grid box. The data range is approximately 170 to 300 K.

    The data has been interpolated to fill in missing values in time at each gridpoint (a linear interpolation). It has then been interpolated from the 144x72 grid (88.75S to 88.75N) to a 144x73 grid (90S-90N) linearly with the first and last latitude interpolated using forward differencing.

    Though the data do not cover the entire grid, an entire grid was stored for ease of use. To pull out the existing latitudes, use gridpoint latitudes 26 to 48.

    There is a "mask" that indicates whether a grid was interpolated in time. A 1 indicates that variable wasn't interpolated and a 0 indicates it was. Since there was also an interpolation in space, if either of the 2 boxes that went into the final value were missing, the mask indicates the grid was interpolated in time.

    MSU Ch3/4 Daily Upper Troposphere Temperatures with Lim93 Correction

    This data set consists of 2.5 deg gridpoint fields of upper tropospheric deep layer temperatures (Ch 3/4) for the tropics (30 S to 30 N). It is a level 3 gridded product that was created from the level 2 orbit files. Data for each scan (there are 11 scan positions per scan line) have been binned according to time and space. The temporal binning is based on the Julian day with ascending and descending orbits combined. The average values are calculated from all footprints which at least partially cover the 2.5 deg by 2.5 deg grid box. The data range is approximately 150 to 290 K. The data precision has been maintained at 0.01 K.

    The data has been interpolated to fill in missing values in time at each gridpoint (a linear interpolation). It has then been interpolated from the 144x72 grid (88.75S to 88.75N) to a 144x73 grid (90S-90N). linearly with the fist and last latitude interpolated using forward differencing.

    Though the data do not cover the entire grid, an entire grid was stored for ease of use. To pull out the existing latitudes, use gridpoint latitudes 26 to 48.

    There is a "mask" that indicates whether a grid was interpolated in time. A 1 indicates that variable wasn't interpolated and a 0 indicates it was. Since there was also an interpolation in space, if either of the 2 boxes that went into the final value were missing, the mask indicates the grid was interpolated in time.

    MSU precipitation

    Daily average and monthly total precipitation values linearily interpolated from a 144x72 grid to a 144x73 grid are provided. The dataset covers 60S-60N only (all longitudes) but a full grid was stored for ease of use.

    Please note that for 1994 and onwards, sea ice has not been correctly taken into account. We have applied a mask to screen out some of the resulting erroneous precipitation values. The data will be replaced with correct values when we receive them. Only precipitation values nearest to the poles are affected.

    For the spatial interpolation, a missing value was stored if either of the 2 gridpoints that went into the interpolated gridpoint was missing. This will result in less grids available near land.

    Monthly totals were computed using the above daily values. A daily average was calculated at each grid for each month using all available days. Then, if the number of days in the month that wasn't missing was 25 or above, the daily average was multiplied by the total days in the month. Otherwise, a missing value was stored. A long term mean file was computed using the monthly total file for 1979-1995. A minimum of 10 years was required for a gridpoint to be kept. Both monthly mean files contain a variable that has the number of days and months respectively that went into the monthly mean and ltm files. This variable is called "nobs".

    Additional information is available from here http://iridl.ldeo.columbia.edu/SOURCES/.NASA/.msu/.dataset_documentation.html.

Caveats:

  • None

Related File Naming & Structure Information:

File Names:

  • var.time.stat.nc   (In directory: /Datasets/msu/)

Dataset Format and Size:

  • PSD standard NetCDF 230 Mbyte file for each daily temperature (packed).
  • PSD standard NetCDF 113 Mbyte file for each daily temperature (packed).
  • PSD standard NetCDF 9 Mbyte file for each long term mean file (packed).
  • PSD standard NetCDF 1 Mbyte file for each long term mean file (packed).

Missing Data:

  • The data are interpolated to eliminate missing data in the temperature datasets. This interpolation is described above in the "Detailed Description" section. Precipitation data have not been interpolated in time.

Citation:

  • Please note: If you acquire MSU data products from PSD, we ask that you acknowledge us in your use of the data. This may be done by including text such as MSU data provided by the NOAA/OAR/ESRL PSD, Boulder, Colorado, USA, from their Web site at http://www.esrl.noaa.gov/psd/ in any documents or publications using these data. We would also appreciate receiving a copy of the relevant publications. This will help PSD to justify keeping the MSU data set freely available online in the future. Thank you!

References:

  • Conrath, B.J., 1972: Vertical resolution of temperature profiles obtained from remote sensing measurements. J. Atmos. Sci., 29, 1262- 1271.
  • Eischeid J.K., H.F. Diaz, R.S. Bradley, and P.D. Jones, 1991: A Comprehensive Precipitation Dataset for Global Land Areas. Department of Energy Carbon Dioxide Research Program Report TR051. Oak Ridge National Laboratory, Oak Ridge, Tennessee.
  • Smith, W.L., H.M. Woolf, C.M. Hayden, D.Q. Wark, and L.M. McMillin, 1979: The TIROS-N operational vertical sounder. Bull. Amer. Meteor. Soc., 60, 1177-1187.
  • Spencer, R.W. and J.R. Christy, 1990: Precise monitoring of global temperature trends from satellites. Science, 247, 1558-1562.
  • Spencer, R.W., J.R. Christy, and N.C. Grody, 1990: Global atmospheric temperature monitoring with satellite microwave measurements: Methods and results 1979-84. J. Climate, 3, 1111-1128.
  • Spencer, R.W. and J.R. Christy, 1992a: Precision and radiosonde validation of satellite gridpoint temperature anomalies, Part I: MSU channel 2. J. Climate, 5, 847-857.
  • Spencer, R.W. and J.R. Christy, 1992b: Precision and radiosonde validation of satellite gridpoint temperature anomalies, Part II: A tropospheric retrieval and trends 1979-90. J. Climate, 5, 858-866.
  • Spencer, R.W. and J.R. Christy, 1993: Precision lower stratospheric temperature monitoring with the MSU: Technique, validation, and results 1979-91. J. Climate, 6, 1194-1204.
  • Spencer, R.W., 1993: Global oceanic precipitation from the MSU during 1979-91 and comparisons to other climatologies. J. Climate, 6, 1301-1326.

Original Source:

  • Roy W. Spencer and Vanessa L. Griffin ES43 NASA Marshall Space Flight Center

Contact:

  • Physical Sciences Division: Data Management
    NOAA/ESRL/PSD
    325 Broadway
    Boulder, CO 80305-3328
    esrl.psd.data@noaa.gov