Open AccessSurface Energy Components and Land Characteristics of a Rice Paddy
Author(s) -
Jichiang Tsai,
BenJei Tsuang,
Po-Sheng Lu,
Ming-Hwi Yao,
Yuan Shen
Publication year - 2007
Publication title -
journal of applied meteorology and climatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.079
H-Index - 134
eISSN - 1558-8432
pISSN - 1558-8424
DOI - 10.1175/2007jamc1568.1
Subject(s) - eddy covariance , bowen ratio , environmental science , latent heat , canopy , daytime , energy balance , albedo (alchemy) , atmospheric sciences , sensible heat , flux (metallurgy) , paddy field , energy budget , meteorology , agronomy , ecosystem , physics , geography , ecology , materials science , art , performance art , metallurgy , biology , art history , thermodynamics , archaeology
Many meteorological and air-quality models require land characteristics as inputs. A field experiment was conducted to study the surface energy budget of a rice paddy in Taiwan. During the day, the energy balance ratio measured by an eddy covariance (EC) system was found to be 95% after considering the photosynthetic and local advected heat fluxes. The observations by the EC system suggest that the Bowen ratio was about 0.18 during the daytime. The EC system also measured the daytime absorbed carbon dioxide flux. The equivalent photosynthetic energy flux was about 1% of the net solar radiation. A reference table describing the land characteristics of rice paddies for use in meteorological and air-quality models is listed that shows that the albedo and the Bowen ratio measured over rice paddies were lower than those listed in many state-of-the-art models. This study proposes simulating latent heat flux by assigning proper values for canopy resistance rather than by assigning constant values for Bowen ratio or surface moisture availability. The diurnal pattern of the canopy resistance of the rice paddy was found to be "U" shaped. Daytime canopy resistance was observed to be 87 s m(-1), and a high canopy resistance (similar to 900 s m(-1)) should be assigned during nighttime periods