Song  Gu, Jie  Li, Bin  Wang, Xiaoqin  Liu, Lulu  Feng, Rongrong  Ma, Ben  Niu, Liang  Zhao, Yingnian  Li, Yanhong  Tang, Mingyuan  Du, 
    A Study of Fitting an Alpine Winter Pasture Evapotranspiration to a Model Based on the Penman-Monteith Equation,
    Journal of Animal and Veterinary Advances,
    Volume 13,Issue 3,
    2014,
    Pages 123-131,
    ISSN 1680-5593,
    javaa.2014.123.131,
    (https://makhillpublications.co/view-article.php?doi=javaa.2014.123.131)
    Abstract: To accurately estimate the magnitude and seasonal dynamics 
  of Evapotranspiration (ET) over an important alpine winter pasture in the Northeastern 
  Qinghai-Tibetan Plateau, researchers employed the Food and Agriculture Organization 
  (FAO) Penman Monteith (P-M) Model. The model was also used to investigate changes 
  in the crop coefficient (k<SUB>c</SUB>) which was calculated as the ratio of 
  the measured actual ET (ET<SUB>a</SUB> from the Eddy Covariance (EC) System) 
  to the reference ET (ET<SUB>0</SUB> from the P-M Model). The results indicated 
  a reference ET of 900 mm year<SUP>-1</SUP> from the alpine meadow pasture which 
  was significantly higher than the actual ET (426 mm year<SUP>-1</SUP>). In addition, 
  the seasonal dynamics of these two ET values differed. The reference ET peaked 
  from April to July while the actual ET was primarily in growing season. The 
  value of k<SUB>c</SUB> exhibited significant seasonal variations within the 
  range 0.3-1.0 with a mean k<SUB>c</SUB> of 0.55 during the growing season. The 
  correlation analysis of the relationship between daily k<SUB>c</SUB> and its 
  primary environmental factors indicated that the Vapor Pressure Deficit (VPD), 
  net Radiation (R<SUB>n</SUB>) and air Temperature (T<SUB>a</SUB>) were the major 
  influencing factors of the daily k<SUB>c</SUB>. The daily k<SUB>c</SUB> showed 
  a linear increase with R<SUB>n</SUB> and T<SUB>a</SUB> and a linear decrease 
  with the VPD. With respect to the biotic factors, the biomass exhibited a significant 
  positive correlation with k<SUB>c</SUB>. Thus, a daily k<SUB>c</SUB> Model is 
  developed as a function of the VPD, R<SUB>n</SUB>, T<SUB>a</SUB> and biomass. 
  This ET Model was validated using 2005 data and showed a satisfactory consistency 
  between the simulated and measured ET.
    Keywords: Evapotranspiration;reference evapotranspiration;crop coefficient;kc;Ta