**3. Simulation scenarios**

As mentioned previously, the model was applied to two selected periods (dry and wet) in an agricultural land described in Section 2 during the summer 2013, and its performance was evaluated. In addition and based on local meteorological information, it was verified that the atmospheric boundary layer developed forced by surface and near surface flow conditions without presence of multilayered thermal inversions [35]. However, this condition is difficult to maintain when precipitation arises. The dry period (no precipitation event) spun from 26 July to August 3 (Julian day 207–216) and wet period from 25 to 30 August (Julian day 237–242).

### **3.1. Dry period**

The experimental data were taken from the plots that monitored soil moisture and soil temperature. The meteorological parameters measured about 10 m away from the plot for the dry period are given in **Table 3** and **Figure 3a**. The hourly average vapor pressure deficit (VPD) was 1.18 kPa. Mean-hourly global radiation was 215 W m−2. The average air temperature was 21°C with maximum of 30.7°C and minimum of 9.8°C also reported in this period. The average RH was approximately 58% and wind speed of 2.36 m s−1.

Evapotranspiration in Northern Agro-Ecosystems: Numerical Simulation and Experimental Comparison http://dx.doi.org/10.5772/intechopen.68347 71


Soil temperate at 5 cm was considered in the study. a Soil moisture from 5 cm depth.

temperature, precipitation, relative humidity, and wind speed as an input to calculate related

The mass of sand, silt, clay, and bulk density was obtained from *in situ* measurements. The

The PSP\_public is the file that needs to be adapted in all parameters that are read by all modules for the given area in which the simulation is carried out. In this case, the FEF site-specific information was input including latitude, longitude, and altitude. Moreover, the soil initial conditions such as soil water potential, soil temperature, and albedo for dry and wet scenarios

In this study, the value of albedo was set as 0.2 for the dry period [33], while a value of 0.15 was applied for the wet period in agriculture land in subarctic region according to previous

As mentioned previously, the model was applied to two selected periods (dry and wet) in an agricultural land described in Section 2 during the summer 2013, and its performance was evaluated. In addition and based on local meteorological information, it was verified that the atmospheric boundary layer developed forced by surface and near surface flow conditions without presence of multilayered thermal inversions [35]. However, this condition is difficult to maintain when precipitation arises. The dry period (no precipitation event) spun from 26 July to August 3 (Julian day 207–216) and wet period from 25 to 30 August (Julian day 237–242).

m−3) 0.28 0.30

The experimental data were taken from the plots that monitored soil moisture and soil temperature. The meteorological parameters measured about 10 m away from the plot for the dry period are given in **Table 3** and **Figure 3a**. The hourly average vapor pressure deficit (VPD) was 1.18 kPa. Mean-hourly global radiation was 215 W m−2. The average air temperature was 21°C with maximum of 30.7°C and minimum of 9.8°C also reported in this period. The aver-

age RH was approximately 58% and wind speed of 2.36 m s−1.

is the saturated soil moisture content, and *b* is constant value.

is satu-

parameter for the hydraulic properties was obtained from Cambell and Shiozawa [32], *K*<sup>s</sup>

parameters. Time step is set to 300 s and input data of 1-h resolution.

**Parameters Dry period Wet period**

Number of days 9 6 Soil temperature (°C) 17.2 15.0 Soil water potential (J kg−1) −30 −6 Albedo 0.20 0.15

rated hydraulic conductivity, *θ*<sup>s</sup>

70 Current Perspective to Predict Actual Evapotranspiration

**3. Simulation scenarios**

**Table 2.** Initial setting for model simulation.

Initial soil moisture (m3

**3.1. Dry period**

needed to be applied into this module (**Table 2**).

studies in the same agricultural setting [34].

**Table 3.** Main meteorological conditions, soil properties, and surface characteristics during periods under study.

**Figure 3.** Global radiation, relative humidity, air temperature, and wind speed measured in the atmospheric surface layer from top to bottom at the experimental plot during the dry period (left panel; 26 July–3 August 2013—Julian day 207–215) and wet period (right panel; 18–30 August 2013—Julian 230–242).

#### **3.2. Wet period**

The meteorological conditions during the wet period 18–30 August 2013 (Julian 230–242) was cooler than the dry period in terms of an average hourly air temperature and soil temperature (**Figure 3b**), while there was a slight difference in solar radiation compared to the dry period (see **Table 3**). The RH was approximately 77% with low level of VPD (0.36 kPa) on average during the wet period (**Table 3**). A total precipitation of 37.60 mm was also reported in this period. However, only data during 25–30 August 2013 (Julian 237–242) are used as the wet period for the simulation in this study.
