Research

Shallow groundwater effect on land surface temperature and surface energy balance

Description, modeling and remote sensing application

PhD thesis (3.2 MB)

In spite of the numerous studies which dealt with heat transfer and temperature distribution within the soil profile and at land surface, a few has investigated their relation to groundwater depth. Investigating the effect of shallow groundwater on skin temperature and surface energy balance elements has two-fold benefits: first, this investigation provides an authenticated solid ground for optimal future utilization of thermal remote sensing in observing the areal extent of shallow groundwater areas and developing future satellite designs. Secondly, it contributes to establishing the basis to include that effect in climate research, weather forecast, and water management studies.

In this PhD project the relations between skin temperature and surface energy balance elements and water table depth were investigated thoroughly by: 

• Field measurements
  Field measurements of soil temperature were conducted in a shallow water table area that lies within Euphrates basin in the north part of Syria. These measurements were conducted to explore the effect of shallow groundwater on soil temperature near land surface. Jointly, groundwater level has been monitored by means of a dense net of observation piezometers. These in situ data are valuable to support both mathematical simulations and satellite observations and products.
• Numerical simulations
  To get detailed insight into the phenomena and the processes that play role in it, a numerical model of the process has been used. This model was useful in investigating the reason behind the above relations, determining the controlling factors and justifying the thermal effect of shallow groundwater on skin temperature and surface energy balance system. We simulated water and energy fluxes within soil profiles subject to actual forcing weather conditions.
• Remote sensing observations
  In moving forward, remotely sensed data are being gathered to be analyzed and examine the capability and applicability of operational satellites to serve the scientific communities as a supportive tool in climate research, water management and energy balance studies.

Figure 1: Study area	Figure 2: Soil temperature logging near land surface
Figure 3: Soil collection for texture composition analysis	Figure 4: Installing temperature, moisture and heat flux loggers
Figure 5: Installing temperature, moisture and heat flux loggers	Figure 6: Installing temperature, moisture and heat flux loggers
Figure 7: Installing temperature, moisture and heat flux loggers	Figure 8: Drilling observation piezometers
Figure 9: Drilling observation piezometers	Figure 10: Drilling observation piezometers
Figure 11: Piezometer	Figure 12: Piezometer
Figure 13: Soil core of the piezometer

Figure 14: A scheme of the mechanism of groundwater effect on skin temperature and surface energy balance