EES: Temperature modeling

Purpose

Both physical and empirical models of temperature are used to explore and predict the heating of soils and snow, which are widely used by farmers and hydrologists to determin crop suitability and spring runoff volumes.

Overview

Measure soil temp at various depths and then applying a damped sinusoidal equation to model your observations. An interactive web model could also be set-up. An activity based on degree day and a simple snowmelt or crop model is also developed.

Time Required

  • Several class periods

Skill Level

  • Advanced

Key Concepts and Skills

  • Concepts: Radiative forcing is almost sinusoidal. Soil temperature decreases exponentially with depth. Crops require sustained soil temperatures above 18 degC to grow. Snow accumulates when the mean temperature remains below 0 degC but begins melting when temperatures warm up.
  • Skills: basic mathematics and plotting

Materials and Tools

Design and Learning Approach

Some models are physical, some are based on observation (empirical). Soil temperature variations with depth is a good example of a physically-based model and can be tested by direct observation. Scientists have developed relationships between temperature and plant growth or snowmelt over many years using the simple concept of degree-day, which is the difference in temperature between a reference value (usually 18 or 0 degC) and the average temperature (defined as the average in maximum and minimum temperatures). Thus, data collected by GLOBE schools is a valuable resource to anyone using these models.

Cost Impact

Training Impact

Systems Impact

Assessment Requirements

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Last updated: 11/25/96
Comments? globe@hwr.arizona.edu