Skip Navigation Links www.nws.noaa.gov 
NOAA logo - Click to go to the NOAA home page National Weather Service   NWS logo - Click to go to the NWS home page
Climate Prediction Center
 
 

CPC Search
About Us
   Our Mission
   Who We Are

Contact Us
   CPC Information
   CPC Web Team

 
HOME > Monitoring & Data > U.S. Soil Moisture Monitoring > Explanation
 
Soil Moisture Explanation Banner
About the dataset (Fan & van den Dool, 2004 JGR)

Model:

Soil moisture is estimated by a one-layer hydrological model (Huang et al., 1996; van den Dool et al, 2003). The model takes observed precipitation and temperature and calculates soil moisture, evaporation and runoff. 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 serveal 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.
Procedure:

The precipitation and temperature are monthly data over the globe from CPC PRECipitation REConstruction 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 Global Land Surface Air Temperature Analysis (Fan, Y. & H. van den Dool, JGR 2008). The climatology is calculated based 1991-2020 data. The soil moisture in the current month will be re-calculated with monthly data on the 8th of next month.

What's next:

The CPC PRECipitation REConstruction over Land will undergo the the following improvements in the near future by Chen et al:

1) orographic adjustment/enhancement
2) dealing with inhomogeneity resulting from changes in number of gauges over time.

Soil moisture calculations will be repeated when such improvements are implemented.


NOAA/ National Weather Service
National Centers for Environmental Prediction
Climate Prediction Center
5200 Auth Road
Camp Springs, Maryland 20746
Climate Prediction Center Web Team
Page last modified: August 22, 2002
Disclaimer Privacy Notice