Estimating Evaporation in a Prairie Landscape under Drought Conditions

Armstrong, Robert W.; Pomeroy, John W.; Martz, Lawrence W.
June 2010
Canadian Water Resources Journal / Revue Canadienne des Ressourc;Summer2010, Vol. 35 Issue 2, p173
Academic Journal
Physically-based atmospheric models of evapotranspiration (ET) that consider the Penman combination energy balance and aerodynamic approach have achieved acceptance as useful tools for obtaining estimates of actual ET from land surfaces. These models have been made applicable to the case of non-saturated conditions through either surface resistance formulations (e.g., Penman-Monteith) or by application of the complementary evaporation theory of feedback between the atmosphere and surface moisture states (e.g., Granger-Gray). Their application becomes complicated under conditions of drought, when extremely low soil moisture availability severely restricts ET from the soil and plants. Under such severe conditions, consideration for the surface water balance and interactions with the balance of available energy and aerodynamic principles are important for accurately estimating actual ET. A modelling application is demonstrated using the Cold Regions Hydrological Model (CRHM) platform to examine the estimation of ET under drought conditions. CRHM allows users to assemble hydrological models by linking a suite of modular physically-based algorithms that describe the individual processes. In this case, the models assembled consider infiltration, evaporation, and soil moisture accounting and are applied to a mixed prairie located at Lethbridge, Alberta, Canada under drought conditions during the growing period in 2000 and 2001. Near surface meteorological and ecological observations used as model input and for evaluating model performance were obtained through the Ameriflux network and the Agriculture and Agri-Food Canada (AFC) Lethbridge Research Centre. Results show that consideration for the effective rooting zone depth of the mixed-prairie at the site is important for estimating actual ET using the Penman-Montieth and Granger-Gray models during severe moisture stress. Relative differences in ET estimates provided by the models are discussed in the context of their contrasting theoretical approaches.


Related Articles

  • Drought severity change in China during 1961-2012 indicated by SPI and SPEI. Wang, Wen; Zhu, Ye; Xu, Rengui; Liu, Jintao // Natural Hazards;Feb2015, Vol. 75 Issue 3, p2437 

    Using monthly meteorological observation data at 633 sites in China during 1961-2012, the drought severity change has been investigated in terms of the Standardized Precipitation Index (SPI) and the Standardized Precipitation Evapotranspiration Index (SPEI) with potential evapotranspiration...

  • Influences of subsurface heterogeneity and vegetation cover on soil moisture, surface temperature and evapotranspiration at hillslope scales. Atchley, Adam L.; Maxwell, Reed M. // Hydrogeology Journal;Mar2011, Vol. 19 Issue 2, p289 

    Physical processes are at the root of determining hydrologic response at all scales. Here, the physical mechanisms linking (1) subsurface heterogeneities to soil moisture and (2) resulting land-surface energy feedbacks to the atmosphere, are examined at the hillslope scale using a fully coupled...

  • Employment of Pedo-transfer functions for predicting initial and final infiltration rates using horton model and soil readily available characteristics. Mousavi, Seyed Bahman // Indian Journal of Agricultural Research;Aug2015, Vol. 49 Issue 4, p333 

    No abstract available.

  • Soil moisture budgets. Manuel, Mark // Geodate;Mar1995, Vol. 8 Issue 1, p5 

    Presents information on soil moisture budgets (SMB), a method used to measure the availability of moisture in a location. Factors affecting soil moisture; Key elements of SMB graphs; Application of the SMB method to drought conditions in Australia from 1994 to 1995. INSET: Student activities..

  • Measuring Salinity from Space.  // Journal of Ocean Technology;2013, Vol. 8 Issue 4, p90 

    The article discusses the application of salinity remote sensing to measure ocean salinity from space. The launch of the Aquarius/SAC-D mission and the European Space Agency Soil Moisture and Ocean Salinity is noted. Open ocean's varied salinity is discussed. The challenge posed by accurate...

  • Simplified stochastic soil-moisture models: a look at infiltration. Rigby, J. R.; Porporato, A. // Hydrology & Earth System Sciences;2006, Vol. 10 Issue 6, p861 

    A simplified, vertically-averaged model of soil moisture interpreted at the daily time scale and forced by a stochastic process of instantaneous rainfall events is compared with a vertically-averaged model which uses a non-overlapping rectangular pulse rainfall model and a more physically based...

  • Accuracy of the Saxton-Rawls Method for Estimating the Soil Water Characteristics for Mineral Soils of Malaysia. Sung, Christopher Teh Boon; Iba, Jane // Pertanika Journal of Tropical Agricultural Science;Aug2010, Vol. 33 Issue 2, p297 

    The purpose of this study was to determine the accuracy of the Saxton-Rawis method in estimating the soil water characteristics Of a wide range of mineral soils of Malaysia. This study found that it was necessary to calibrate the Saxton-Rawis method for the soils of Malaysia. The developed...

  • Evaluating Infiltration Mechanisms Using Breakthrough Curve and Mean Residence Time. Simin, Qu; Tao, Wang; Weimin, Bao; Peng, Shi; Peng, Jiang; Minmin, Zhou; Zhongbo, Yu // Water Resources Management;Nov2013, Vol. 27 Issue 13, p4579 

    Determination of infiltration mechanism is crucial for the calculation of infiltration flux in the soil which would influence the water balance computation. Two infiltration experiments with different isotopic compositions of rainfall were conducted to analyze the infiltration type by measuring...

  • Wireless moisture monitors undergo study. Brazil, III, Everett // Kansas Farmer (0022-8583);Feb2012, Vol. 150 Issue 2, pIE8 

    The article focuses on the usefulness of handy advancements in cellphone technology which allows growers to monitor soil moisture content and irrigation systems, and give them the ability to make irrigation decisions without being there in the fields. According to Calvin Perry of C. M. Stripling...


Read the Article


Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics