NCAR Header
Recent Publications

  • Swenson, S., and J. Wahr,
  • Monitoring the Water Balance of Lake Victoria, East Africa, from Space, J. Hydrol., in review 2009.

    The water balance of Lake Victoria is quantified using numerous (~10) satellite datasets. Includes an assessment of the relative effects of drought and human management on the lake decline of the mid-2000s.

  • Swenson, S., D. Chambers, and J. Wahr,
  • Estimating Geocenter Variations from a Combination of GRACE and Ocean Model Output, J. Geophys. Res. - Solid Earth, 113, B08410, doi:10.1029/2007JB005338, 19 August 2008.

    The degree one spherical harmonic coefficient obtained from an ocean model has contributions from global coefficients of all degrees. Contributions for degrees ≥ 2 can be removed using GRACE data, isolating the global degree one term.

  • Swenson, S., J. Famiglietti, J. Basara, and J. Wahr,
  • Estimating Profile Soil Moisture and Groundwater Storage Variations in the Southern Great Plains Using GRACE Satellite Gravimetric and Oklahoma Mesonet Soil Moisture Data, Wat. Resour. Res., 44, W01413, doi:10.1029/2007WR006057, 2008.

    In situ soil moisture estimates from the Oklahoma Mesonet, extrapolated to depth, were subtracted from GRACE estimates of total water storage resulting in a time series of groundwater variations for the region of the southern Great Plains.

  • Swenson, S., and J. Wahr,
  • Multi-sensor analysis of water storage variations of the Caspian Sea, Geophys. Res. Lett., 34, L16401, doi:10.1029/2007GL030733, 2007.

    Caspian Sea water storage variations from GRACE were compared with altimetric sea surface heights from Jason-1 corrected for thermal expansion using MODIS sea surface temperatures.

  • Swenson, S., P. J.-F. Yeh, J. Wahr, and J. Famiglietti,
  • A comparison of terrestrial water storage variations from GRACE with in situ measurements from Illinois, Geophys. Res. Lett., 33, L16401, doi:10.1029/2006GL026962, 2006.

    The first GRACE validation study using in situ observations of soil moisture and groundwater variability.

  • Swenson,S., and J. Wahr,
  • Post-processing removal of correlated errors in GRACE data, Geophys. Res. Lett., 33, L08402, doi:10.1029/2005GL025285, 2006.

    The first study to describe the structure of correlated errors in GRACE gravity field data. It also provides a method for removing much of these correlations while minimizing the signal degradation.

  • Wahr,J., S. Swenson, and I. Velicogna,
  • The Accuracy of GRACE Mass Estimates, Geophys. Res. Lett., 33, L06401, doi:10.1029/2005GL025305, 2006.

    An assessment of the error characteristics of GRACE data.

  • Swenson, S., and P.C.D. Milly,
  • Systematic Climate-Model Errors in Seasonal Water Storage on Continents Revealed by Satellite Gravimetry, Water Resour. Res., Vol. 42, No. 3, W03201, 10.1029/2005WR004628,01 March, 2006.

    GRACE data are used to assess the ability of land surface models to simulate the seasonal cycle of total water storage.

  • Swenson, S., and J. Wahr,
  • Estimating Large-scale Precipitation Minus Evapotranspiration from GRACE Satellite Gravity Measurements, J. Hydrometeorology, Vol. 7, No. 2, pp. 252-270, doi: 10.1175/JHM478.1, 2006.

    GRACE total water storage estimates combined with river discharge data can be used to estimate P-E, or net precipitation, which can be used to assess moisture transport in AGCMs.

  • Wahr, J., S. Swenson, V. Zlotnicki, I. Velicogna,
  • Time-Variable Gravity from GRACE: First Results, Geophys. Res. Lett., 31, doi:10.1029/2004GL019779, 2004.

    Results from the first year of GRACE data with error assessment.

  • Swenson, S., J. Wahr, and P.C.D. Milly,
  • Estimated accuracies of regional water storage anomalies inferred from GRACE, Water Resour. Res., 39(8), 1223, doi:10.1029/2002WR001808, 2003.

    A simulation study of the tradeoffs between satellite error minimization and signal degradation from the use of optimal GRACE averaging kernels.

  • Swenson, S., and J. Wahr,
  • Monitoring Changes in Continental Water Storage With GRACE, Space Sci. Rev., 108, 345-354, 2003.

    A brief description of how GRACE gravity field data can be used to estimate total water storage.

  • Swenson, S., and J. Wahr,
  • Methods of inferring regional surface-mass anomalies from Gravity Recovery and Climate Experiment (GRACE) measurements of time-variable gravity, J. Geophys. Res., 107(B9), 2193, doi:10.1029/2001JB000576, 2002.

    A description of the process by which GRACE gravity field data are converted to spatial averages of surface mass variability.

  • Swenson, S., and J. Wahr,
  • Estimated effects of the vertical structure of atmospheric mass on the time-variable geoid, J. Geophys. Res., 107(B9), 2194, doi:10.1029/2000JB000024, 2002.

    An examination of the accuracy to which the atmospheric contribution of the gravity field can be modeled and removed using various simplified models of the vertical structure of mass in the atmosphere.