*2.3. Field Experiments*

The field experiment was carried out over four typical sunny days in four seasons from 2015 to 2016, from 8:00 a.m. to 5:00 p.m. An infrared thermal imager (Fluke Ti55FT, Fluke Corp., Everett, WA, USA) was used to record the surface temperatures vertically down, at a height of 1.5 m. The measuring wavelength of the infrared thermal imager was 8–14 μm, and its resolution was 0.05 ◦C. The emissivity of the hedges and lawn in our study was set up to be 0.98 according to empirical value [37]. The imager could give out the emissivity-corrected temperature directly. Each thermal infrared image contains 76,800 temperature data points (320 × 240). Three images were taken of each plant at each hour. Before the measurement, the thermal camera was calibrated against a blackbody measurement.

Air temperature and other meteorological factors were recorded by a Bowen ratio system at heights of 2 m and 1.5 m. The system was installed in the middle of the lawn. All the data from the Bowen ratio system were sampled and recorded at intervals of 1 min and 10 min with a Campbell CR1000 data logger. The sensor information is shown in Table 1.

**Table 1.** Type of sensor, measurement height, and resolutions of the equipment in the Bowen ratio system.

