Global Land Surface Monitor and Prediction

Updated daily

Developend and maintained by: Yun Fan & Li Xu

Important Details about the Leaky Bucket Model and Data

  • Model

    Soil moisture and snowpack are estimated by a one-layer hydrological model (Huang et al., 1996; van den Dool et al., 2003; Fan & van den Doll, 2004 JGR; Zeng et al., 2020). The model takes observed precipitation and temperature and calculates soil moisture, evaporation, runoff and snowpack. The potential evaporation is estimated from observed temperature.

  • Model parameters are constant spatially (tuned based on Oklahoma observed runoff data).

    Tuning the model to runoff of several small river basins in eastern Oklahoma resulted in a maximum holding capacity of 760mm of water. Along with a common porosity of 0.47 this implies a soil column of 1.6 meter.

  • Forcing Datasets

    The precipitation and temperature (0.5x0.5 degree resolution) are daily observed data over the globe from CPC Daily Unified Precipitation Analysis over Land (Chen, M., P. Xie, J. E. Janowiak and P. A. Arkin, 2002: Global land precipitation: A 50-yr monthly analysis based on gauge observations. J. Hydrometeor., 3, 249-266) & CPC Daily Global Land Surface Air Temperature Analysis (Wei Shi 2012, Fan Y. & H. van den Dool, JGR 2008). The climatology is calculated based 1981-2010 data.

  • For full documentation visit this link.


  • Full Field:

    unit is mm and in a single column of 1.6 meter. The maximum is set to be 760 mm in the model.

  • Wetness:

    ratio of calculated soil moisture (mm) to the maxinum (760mm).
  • Anomaly:

    departure from 1981-2010 Climatology (unit: mm)
  • Soil Moisture Percentile:

    the percentile against 1979 to 2019 histroical soil moisture records




Download the Data by this link


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