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The Implications of Using Estimated Solar Radiation on the Derivation of Potential Evapotranspiration and Soil Moisture Deficit within an Embankment

Lookup NU author(s): Dr Peter Helm, Dr Ross Stirling, Professor Stephanie Glendinning


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In the absence of measured data, potential evapotranspiration is commonly estimated at a given siteaccording to the methods outlined by Allen et al. (1998). Their work provides a system of calculationto derive the solar radiation values required to predict the available energy for water vaporisation. Assuch estimations of potential evapotranspiration are very dependent on the available data. In this work,meteorological parameters including air temperature, relative humidity, wind speed, near-surface soiltemperature, shortwave and net radiation were measured for a complete year at the BIONICS trialembankment, Newcastle, UK.Estimates were made of the net radiation for a number of cases (1. no radiation data and 2. measuredincident short wave radiation) and compared to the field monitored values. These data were in turn usedto estimate the potential evapotranspiration () from the embankment.The results indicate that the net radiation and hence  derived entirely from estimated data aresignificantly higher than those derived with measured shortwave radiation and the measured netradiation. Results for estimates of  derived from monitored shortwave and net radiation data aremuch closer to each other. In order to investigate the potential effects on slope stability, an assessmentof soil moisture deficit was undertaken and the results indicate that numerical models using the differentestimates of  would likely produce significantly different results in terms of generated suctions andhence the potential for shrink-swell cycles and strain softening behavior.

Publication metadata

Author(s): Helm P, Stirling RA, Glendinning S

Publication type: Conference Proceedings (inc. Abstract)

Publication status: Published

Conference Name: 3rd International Conference on Transportation Geotechnics

Year of Conference: 2016

Pages: 697-707

Online publication date: 13/07/2016

Acceptance date: 13/07/2016

ISSN: 1877-7058

Publisher: Elsevier


DOI: 10.1016/j.proeng.2016.06.105

Series Title: Procedia Engineering - Advances in Transportation Geotechnics 3