Effects of different land use types on potential evapotranspiration in the Beijing-Tianjin-Hebei region, North China

Abstract

Potential evapotranspiration (ET 0) is vital for hydrologic cycle and water resource assessments as well as crop water requirement and irrigation demand assessments. The Beijing-Tianjin-Hebei region (Jing-Jin-Ji)-an important, large, regional, economic community in China has experienced tremendous land use and land cover changes because of urbanisation and ecological restoration, affecting the hydrologic cycle and water resources of this region. Therefore, we analysed ET 0 in this region using climate data from 22 meteorological stations for the period 1991-2015 to understand this effect. Our findings show that ET 0 increased significantly at a rate of 7.40 mm per decade for the region. Based on the major land use type surrounding them, the meteorological stations were classified as urban, farmland, and natural stations using the 2015 land use dataset. The natural stations in the northern mountainous area showed a significant increase in ET 0 , whereas most urban and farmland stations in the plain area showed a decrease in ET 0 , with only a few of the stations showing an increase. Based on the different ET 0 trends for different land use types, these stations can be ranked as follows: urban stations (trend value: −4.663 to −1.439) > natural stations (trend value: 2.58 to 3.373) > farmland stations (trend value: −2.927 to −0.248). Our results indicate that land use changes affect meteorological parameters, such as wind speed and sunshine duration, which then lead to changes in ET 0. We noted that wind speed was the dominant parameter affecting ET 0 at all the natural stations, and wind speed and sunshine duration were the dominant parameters affecting ET 0 at most of the urban stations. However, the main controlling parameters affecting ET 0 at the farmland stations varied. These results present a HAN Jingyan et al.: Effects of different land use types on potential evapotranspiration in Beijing-Tianjin-Hebei 923 scope for understanding land use impact on ET 0 , which can then be applied to studies on sustainable land use planning and water resource management.

Estimation of Evapotranspiration in Sparse Vegetation Areas by Applying an Optimized Two-Source Model

“…Although the field data of regional ET is lacking to estimate the improved model, the spatial and temporal trends of ET in many previous studies were consistent with the results of this paper [62][63][64]. (2) When calculating the canopy boundary resistance, the improved model assumes that the vegetation source and the soil source are on the same plane, and ignores the water and energy exchange in the vertical direction.…”

Changes in Reference Evapotranspiration over Southwest China during 1960–2018: Attributions and Implications for Drought

“…Therefore, it is commonly estimated from weather data (sunshine duration, wind speed, temperature, and relative humidity) by using the Penman-Monteith method [5] to derive the so-called reference evapotranspiration (ET 0 ), which is usually the basis for the actual evapotranspiration [6]. Variation in ET 0 is a consequence of variations in all meteorological factors and very susceptible to land-use change [7], and can be seen as the most excellent indicator for the activities of humans, climate change, and the water cycle. Therefore, analyzing the variation in ET 0 has been widely applied as a valuable reference to assess ecological changes and agricultural water requirements.…”

Trade-Offs and Synergies of Ecosystem Services in the Pearl River Delta Urban Agglomeration

“…From 2000 to 2018, water yield in most areas of the PRD showed little change; the increasing part of water yield is concentrated in the middle, while the decreasing part is scattered (Figure 5). The area of increasing water yield overlapped with the area of increasing construction land, and the evapotranspiration of urban construction land is less than that of other land types [43].…”