Simulating Soil Moisture & Temperature Regimes with the
Newhall Simulation Model

Contents

1. Soil Moisture & Temperature Regimes
2. Simulating SMR and STR with the Newhall Simulation Model
3. How does the NSM work?
4. Limitations of the model
5. Applications
6. Credits
7. Download the model
   • Interactive (PC, requires BASICA)
   • Batch (PC, requires MS-DOS)

Soil Moisture & Temperature Regimes

These are concepts from the USDA Soil Taxonomy system of soil classification. The idea is that the soil climate is a soil property that affects soil use, soil ecology, and soil behaviour. Keys to Soil Taxonomy 8th edition they are defined as follows:

• Soil Moisture Regimes according to KST
• Soil Temperature Regimes according to KST

Several soil scientists have suggested that subdivisions of these regimes would be useful for more exact predictions of soil behaviour. One such proposed sub-division was implemented by Van Wambeke in his version of the Newhall model.

These divisions were first used in the following reports:

• Van Wambeke, A. (1985), Calculated soil moisture and temperature regimes of Asia: a compilation of soil climatic regimes calculated by using a mathematical model developed by F. Newhall, New York State College of Agriculture and Life Sciences, Cornell University Soil Management Support Services, Soil Conservation Service, U.S. Dept. of Agriculture, Ithaca, N.Y. Washington, DC.
• Van Wambeke, A. (1981), Calculated soil moisture and temperature regimes of South America: a compilation of soil climatic regimes calculated by using a mathematical model developed by F. Newhall, New York State College of Agriculture and Life Sciences, Cornell University, Dept. of Agronomy; Soil Management Support Services, Soil Conservation Service, U.S. Dept. of Agriculture, Ithaca, NY: Washington, DC.
• Van Wambeke, A. (1982), Calculated soil moisture and temperature regimes of Africa: a compilation of soil climatic regimes calculated by using a mathematical model developed by F. Newhall, New York State College of Agriculture and Life Sciences, Cornell University Soil Management Support Services, Soil Conservation Service, U.S. Dept. of Agriculture, Ithaca, N.Y. Washington, DC.
• Van Wambeke, A. (1987), Soil moisture and temperature regimes of Central America, Caribbean, Mexico, Dept. of Agronomy, NY State College of Agriculture and Life Sciences Soil Management Support Services, Soil Conservation Service, US Dept. of Agriculture, Ithaca, NY, USA.

Simulating SMR and STR with the Newhall Simulation Model

There are two steps:

1. The Newhall model is run on a time-sequence of monthly climate data, and the daily moisture status (in the control section) and temperature status (at the defined depth) are recorded;
2. The time-series of moisture and temperature status are summarised according to the rules of the soil moisture & temperature regimes, thereby classifying the site.

How does the model work?

The Newhall Simulation Model for estimating soil moisture & temperature regimes, an explanation by Armand Van Wambeke (PDF, 34Kb)

Limitations of the model

The Newhall model does not take into account:

• Soils with groundwater influence, i.e., that are not freely-drained within the modelled depth
• Soils with lateral inflows or outflows of water, unless these two would balance each other
• Soils with restricted infiltration
• Snowpack, freezing and snowmelt as they affect the water balance

The model is not based on fundamental soil physics.

Applications

This is a list of soil climate studies that have used the Newhall model

• Soil Climate Regimes of Pennsylvania (USA)

  Good explanation of methodology: Newhall on individual stations, with regression modelling on a DTM to produce a climate surface. By Bill Waltman and collaborators.

Credits

Conceptual model

Franklin Newhall, Soil Conservation Service, USDA

FORTRAN implementation

Armand Van Wambeke (RIP), Cornell University

BASIC implementation

Michael Tolomeo, Cornell University

Paul Hastings

Armand Van Wambeke (RIP)

Web page and keeper of the flame

David G Rossiter