• Budyko, M. I., 1974: Climate and Life. Academic, 508 pp.

  • Chen, T. H., and Coauthors. 1997: Cabauw experimental results from the Project for Intercomparison of Land-Surface Parameterization Schemes. J. Climate, 10 , 11941215.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Darnell, W. L., Staylor W. F. , Gupta S. K. , and Denn F. M. , 1988: Estimation of surface insolation using sun-synchronous satellite data. J. Climate, 1 , 820835.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Foley, J. A., Prentice I. C. , Ramankutty N. , Levis S. , Pollard D. , Sitch S. , and Haxeltine A. , 1996: An integrated biosphere model of land surface processes, terrestrial carbon balance, and vegetation dynamics. Global Biogeochem. Cycles, 10 , 603628.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Gupta, S. K., Darnell W. L. , and Wilber A. C. , 1992: A parameterization of longwave surface radiation from satellite data: Recent improvements. J. Appl. Meteor., 31 , 13611367.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • IGPO, 1999: ISLSCP Initiative II receives funding. GEWEX News, Vol. 9, No. 3, International GEWEX Project Office, 8.

  • Koster, R. D., Oki T. , and Suarez M. J. , 1999: The offline validation of land surface models: Assessing success at the annual timescale. J. Meteor. Soc. Japan, 77 , 257263.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Meeson, B. W., Coprew F. E. , McManus J. M. P. , Myers D. M. , Closs J;th W. , Sun K-J. , Sunday D. J. , and Sellers P. J. , 1995: ISLSCP Initiative I—Global Data Sets for Land–Atmosphere Models, 1987-1988, Vols. 1–5,. NASA, CD-ROM, USA_NASA_GDAAC_ISLSCP_001/002/003/004/005.

    • Search Google Scholar
    • Export Citation
  • Milly, P. C. D., 1993: An analytic solution of the stochastic storage problem applicable to soil water. Water Resour. Res., 29 , 37553758.

  • Milly, P. C. D., . 1994a: Climate, soil water storage, and the average annual water balance. Water Resour. Res., 30 , 21432156.

  • Milly, P. C. D., . 1994b: Climate, interseasonal storage of soil water, and the annual water balance. Adv. Water Resour., 17 , 1924.

  • Milly, P. C. D., and Shmakin A. B. , 2002a: Global modeling of land water and energy balances. Part I: The Land Dynamics (LaD) model. J. Hydrometeor., 3 , 283299.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Milly, P. C. D., . 2002b: Global modeling of land water and energy balances. Part II: Land-characteristic contributions to spatial variability. J. Hydrometeor., 3 , 301310.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • van Dam, T., Wahr J. , Milly P. C. D. , Shmakin A. B. , Blewitt G. , Lavallée D. , and Larson K. M. , 2001: Crustal displacements due to continental water loading. Geophys. Res. Lett., 28 , 651654.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Wahr, J., Molenaar M. , and Bryan F. , 1998: Time variability of the earth's gravity field: Hydrological and oceanic effects and their possible detection using GRACE. J. Geophys. Res., 103 , 3020530230.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Xie, P., and Arkin P. A. , 1997: Global precipitation: A 17-year monthly analysis based on gauge observations, satellite estimates, and numerical model outputs. Bull. Amer. Meteor. Soc., 78 , 25392558.

    • Crossref
    • Search Google Scholar
    • Export Citation
All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 133 26 2
PDF Downloads 22 13 0

Global Modeling of Land Water and Energy Balances. Part III: Interannual Variability

View More View Less
  • 1 NOAA/Geophysical Fluid Dynamics Laboratory, Princeton, New Jersey
  • | 2 U.S. Geological Survey and NOAA/Geophysical Fluid Dynamics Laboratory, Princeton, New Jersey
Restricted access

Abstract

The Land Dynamics (LaD) model is tested by comparison with observations of interannual variations in discharge from 44 large river basins for which relatively accurate time series of monthly precipitation (a primary model input) have recently been computed. When results are pooled across all basins, the model explains 67% of the interannual variance of annual runoff ratio anomalies (i.e., anomalies of annual discharge volume, normalized by long-term mean precipitation volume). The new estimates of basin precipitation appear to offer an improvement over those from a state-of-the-art analysis of global precipitation (the Climate Prediction Center Merged Analysis of Precipitation, CMAP), judging from comparisons of parallel model runs and of analyses of precipitation–discharge correlations. When the new precipitation estimates are used, the performance of the LaD model is comparable to, but not significantly better than, that of a simple, semiempirical water-balance relation that uses only annual totals of surface net radiation and precipitation. This implies that the LaD simulations of interannual runoff variability do not benefit substantially from information on geographical variability of land parameters or seasonal structure of interannual variability of precipitation.

The aforementioned analyses necessitated the development of a method for downscaling of long-term monthly precipitation data to the relatively short timescales necessary for running the model. The method merges the long-term data with a reference dataset of 1-yr duration, having high temporal resolution. The success of the method, for the model and data considered here, was demonstrated in a series of model–model comparisons and in the comparisons of modeled and observed interannual variations of basin discharge.

Current affiliation: Institute of Geography, Russian Academy of Sciences, Moscow, Russia

Corresponding author address: Dr. P. C. D. Milly, Water Resources Division, U.S. Geological Survey, NOAA/Geophysical Fluid Dynamics Laboratory, P.O. Box 308, Princeton, NJ 08542. Email: cmilly@usgs.gov

Abstract

The Land Dynamics (LaD) model is tested by comparison with observations of interannual variations in discharge from 44 large river basins for which relatively accurate time series of monthly precipitation (a primary model input) have recently been computed. When results are pooled across all basins, the model explains 67% of the interannual variance of annual runoff ratio anomalies (i.e., anomalies of annual discharge volume, normalized by long-term mean precipitation volume). The new estimates of basin precipitation appear to offer an improvement over those from a state-of-the-art analysis of global precipitation (the Climate Prediction Center Merged Analysis of Precipitation, CMAP), judging from comparisons of parallel model runs and of analyses of precipitation–discharge correlations. When the new precipitation estimates are used, the performance of the LaD model is comparable to, but not significantly better than, that of a simple, semiempirical water-balance relation that uses only annual totals of surface net radiation and precipitation. This implies that the LaD simulations of interannual runoff variability do not benefit substantially from information on geographical variability of land parameters or seasonal structure of interannual variability of precipitation.

The aforementioned analyses necessitated the development of a method for downscaling of long-term monthly precipitation data to the relatively short timescales necessary for running the model. The method merges the long-term data with a reference dataset of 1-yr duration, having high temporal resolution. The success of the method, for the model and data considered here, was demonstrated in a series of model–model comparisons and in the comparisons of modeled and observed interannual variations of basin discharge.

Current affiliation: Institute of Geography, Russian Academy of Sciences, Moscow, Russia

Corresponding author address: Dr. P. C. D. Milly, Water Resources Division, U.S. Geological Survey, NOAA/Geophysical Fluid Dynamics Laboratory, P.O. Box 308, Princeton, NJ 08542. Email: cmilly@usgs.gov

Save