Woody plantations play a curtail role in ecological security along
coastal zones. Understanding of energy partitioning and
evapotranspiration (ET) over black locust plantations can reveal
land-atmosphere interaction process and help us to optimize this
plantation for land management in the Yellow River Delta. In this study,
we investigated energy fluxes, ET in particular, and their related
biophysical factors using eddy covariance techniques over a black locust
plantation in 2016, 2018, and 2019. Downward longwave radiation offsets
84%–85% of upward longwave radiation, upward shortwave radiation
accounted for 12%–13% of downward shortwave radiation, and the ratio
of net radiation (Rn) to downward radiation was 18%–19%in the three
years. During growing seasons, latent heat flux was the largest
components among radiation balance terms; during non-growing seasons,
sensible heat flux was a dominant component. ET was mainly controlled by
Rn, air temperature, vapor pressure deficit and leaf area index (LAI).
Annual ET was smaller than the sum of precipitation and irrigation, and
cumulative ET was larger than cumulative precipitation during
non-growing seasons. The phenology of black locust influenced the
seasonal variation in daily ET, mainly via LAI. ET was larger under sea
wind than under land wind, mainly because soil water content at 10-cm
depth was greater under sea wind in daytime. Seasonal patterns of daily
evaporative fraction, Bowen ratio, crop coefficient, Priestley–Taylor
coefficient, surface conductance (gs), and decoupling coefficient were
mainly controlled by LAI, and the threshold value of daily gs was
approximately 8 mm s−1 over the studied plantation.
Energy partitioning and evapotranspiration over a black locust plantation in the Yellow River Delta
