Abstract
Abstract. A 10 × 10 km irrigated biomass plantation was simulated in an arid region of Israel to simulate diurnal energy balances during the summer of 2012 (JJA). The goal is to examine daytime horizontal flux gradients between plantation and desert. Simulations were carried out within the coupled WRF-NOAH atmosphere/land surface model. MODIS land surface data was adjusted by prescribing tailored land surface and soil/plant parameters, and by adding a controllable sub-surface irrigation scheme to NOAH. Two model cases studies were compared – Impact and Control. Impact simulates the irrigated plantation. Control simulates the existing land surface, where the predominant land surface is bare desert soil. Central to the study is parameter validation against land surface observations from a desert site and from a 400 ha Simmondsia chinensis (jojoba) plantation. Control was validated with desert observations, and Impact with Jojoba observations. Model evapotranspiration was validated with two Penman–Monteith estimates based on the observations. Control simulates daytime desert conditions with a maximum deviation for surface 2 m air temperatures (T2) of 0.2 °C, vapour pressure deficit (VPD) of 0.25 hPa, wind speed (U) of 0.5 m s−1, surface radiation (Rn) of 25 W m−2, soil heat flux (G) of 30 W m−2 and 5 cm soil temperatures (ST5) of 1.5 °C. Impact simulates irrigated vegetation conditions with a maximum deviation for T2 of 1–1.5 °C, VPD of 0.5 hPa, U of 0.5 m s−1, Rn of 50 W m−5, G of 40 W m−2 and ST5 of 2 °C. Latent heat curves in Impact correspond closely with Penman–Monteith estimates, and magnitudes of 160 W m−2 over the plantation are usual. Sensible heat fluxes, are around 450 W m−2 and are at least 100–110 W m−2 higher than the surrounding desert. This surplus is driven by reduced albedo and high surface resistance, and demonstrates that high evaporation rates may not occur over Jojoba if irrigation is optimized. Furthermore, increased daytime T2 over plantations highlight the need for hourly as well as daily mean statistics. Daily mean statistics alone may imply an overall cooling effect due to surplus nocturnal cooling, when in fact a daytime warming effect is observed.
Highlights
The large-scale implementation of biomass plantations in arid regions is the subject of recent research due to the perceived potential for carbon sequestration, energy production, agricultural development and environmental services (Becker et al, 2013; Beringer et al, 2011)
This study focuses on the parameterization and validation of the WRF (Skamarock et al, 2008) with its land surface models (LSM) NOAH (Chen and Dudhia, 2001) model for the region/vegetation/irrigation/soils, and on the comparison of energy fluxes over the desert and plantation
In relation to subsequent impact studies, this study focuses on the configuration and validation of the model for an arid region
Summary
The large-scale implementation of biomass plantations in arid regions is the subject of recent research due to the perceived potential for carbon sequestration, energy production, agricultural development and environmental services (Becker et al, 2013; Beringer et al, 2011). Such plantations are becoming feasible through modern desalination (Khawaji et al, 2008; Fritzmann et al, 2007), wastewater (Hamilton et al, 2007; Oron et al, 1999), and irrigation techniques (e.g., see Spreer et al 2007). Branch et al.: Simulation of semi-arid biomass plantations and irrigation using the WRF-NOAH model
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
