Spatial and Temporal Variations of Potential Evapotranspiration in the Loess Plateau of China During 1960–2017

Abstract

Potential evapotranspiration (ET0) is an integral component of the hydrological cycle and the global energy balance, and its long-term variation is of much concern in climate change studies. The Loess Plateau is an important area of agricultural civilization and water resources research. This study analyzed the spatial and temporal evolution processes and influential parameters of ET0 at 70 stations in different topographical areas of the Chinese Loess Plateau (CLP). Using the Mann–Kendall trend, Cross wavelet transform, and the ArcGIS platform, the ET0 of each station was quantified using the Penman–Monteith equation, and the effects of climatic factors on ET0 were assessed by analyzing the correlation coefficients and contribution rates of the climatic factors. The results showed that: (1) the overall trend of the ET0 in different terrains of the Loess Plateau is consistent, however, the ET0 values differ; the hill region (HR) has the highest ET0, followed by the valley region (VR), and the mountain region (MR) has the lowest, and ET0 changes differ between seasons. (2) Spatial distribution characteristics of multiyear mean ET0 in the study are as follows: the ET0 values in mountain and hilly areas are decreasing from west to east, and the higher mean annual ET0 value in the VR is mainly concentrated in the eastern CLP. (3) In the past 58 years, the annual mean and the seasonal ET0 of the region showed increasing trends, however, differences in different terrains were obvious. (4) ET0 has significant correlations with El Niño–Southern Oscillation (ENSO), Pacific–North American teleconnection (PNA), and Atlantic Multidecadal Oscillation (AMO). The resonance period of ET0 and ENSO was 3–6 a, mainly in 1976–1985. The mean coherence phase angle was close to 360°, indicating that ET0 lags behind PNA by approximately 2–6 a; ET0 has a very strong positive correlation with AMO. (5) Relative humidity (RH) is the main influencing factor of ET0 change in the Loess Plateau. Temperature (T) variation has the highest contribution rate (42%) to the regional ET0 variation in the entire CLP. We should pay more attention to the variation of evaporation under future climate change, especially temperature change.

Evolution of Ecological Security in the Tableland Region of the Chinese Loess Plateau Using a Remote-Sensing-Based Index

“…In this region, the annual temperature oscillated between 8 and 15.6 • C, and the annual rainfall was approximately 450-709 mm, whose temporal distribution was uneven, as 60% of the total precipitations occurred, on average, from July to September. We observed an annual sunshine duration of 2099 to 2900 h, and a leaf abscission period of 156 to 223 days [2,30,34].…”

Effects of vegetation cover and slope on soil erosion in the Eastern Chinese Loess Plateau under different rainfall regimes

“…As one of the most severely soil erosion regions in the world, the serious soil erosion of CLP not only leads to the decline of soil fertility but also results in regional environmental pollution (Ritsema, 2003;Ramos-Scharrón & Figueroa-Sánchez, 2017). In the last 50 years, the meteorological data shown the climate of CLP had an obvious tendency of warming and drying (Sun et al, 2020). However, the decreased rainfall did not reduce the soil loss in this region, while the soil erosion increased continuously, which was mainly due to the lower density of vegetation cover for lacking of enough water and human destruction.…”

Comparison and applicability analysis of different evapotranspiration models for maize farmland in the lower Yellow River Plain based on the eddy covariance system

“…2022). As a result, extreme heat waves and agricultural droughts can lead to a reduction in agricultural crop yields and water resources to meet human needs (Pan et al 2019;Sun et al 2020;Zhang et al 2023). These issues reflect the importance of the potential evapotranspiration in energy and water cycles (Ning et al 2020).…”