Surface energy partitioning and evapotranspiration in a Pinus tabuliformis plantation in Northeast China

Xiang Gao; Jinsong Zhang; Jinfeng Cai; Songyi Pei; Linqi Liu; Ping Meng; Hui Huang

doi:10.3389/fpls.2023.1048828

Surface energy partitioning and evapotranspiration in a Pinus tabuliformis plantation in Northeast China

Front Plant Sci. 2023 Feb 3:14:1048828. doi: 10.3389/fpls.2023.1048828. eCollection 2023.

Authors

Xiang Gao^{1

2

3}, Jinsong Zhang^{1

2

3}, Jinfeng Cai², Songyi Pei⁴, Linqi Liu^{1

2

3}, Ping Meng^{1

2

3}, Hui Huang^{1

2

3}

Affiliations

¹ Key Laboratory of Tree Breeding and Cultivation of National Forestry and Grassland Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, China.
² Collaborative Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing, China.
³ Henan Xiaolangdi Earth Critical Zone National Research Station on the Middle Yellow River, Jiyuan, China.
⁴ State-owned Jianping County Heishui Mechanized Forest Farm, Chaoyang, China.

Abstract

Examining the land-atmosphere interaction in vegetation rehabilitation areas is important for better understanding of land surface processes affected by human activities. In this study, energy flux observations were used to investigate surface energy partitioning and evapotranspiration (ET) in a Pinus tabuliformis plantation in Northeast China in 2020 and 2021. The sensible heat flux (H) was the dominant component of R_n, and the ratio of H to the latent heat flux was higher than 1 at all growth stages. The two most important factors influencing the midday evaporative fraction and daily ET were the normalized difference vegetation index (NDVI) and soil water content at 10 cm depth (SWC₁₀). Cumulative precipitation (P) minus ET was 62.83 and 239.90 mm in 2020 (annual P of 435.2 mm) and 2021 (annual P of 632.8 mm), respectively. The midday Priestley-Taylor coefficient (α), surface conductance (g_s), and decoupling coefficient increased gradually from the onset of the mid-growing stage and decreased from the later growing stage. Midday α and g_s increased with NDVI and SWC₁₀ increasing until the NDVI (0.5) and SWC₁₀ (0.17 mm³ mm^-3) thresholds were reached, respectively. Midday α and g_s were significantly influenced by vapor pressure deficit below 3 kPa, and the threshold value of midday g_s was approximately 12 mm s^-1. In conclusion, this Pinus tabuliformis plantation regulated surface energy partitioning properly, and left a part of P for surface runoff and groundwater recharge in the semiarid region of Northeast China.

Keywords: Northeast China; Pinus tabuliformis plantation; evapotranspiration; surface energy partitioning; surface parameters.

Grants and funding

This project was supported financially by the Fundamental Research Funds for the CentralNonprofit Research Institution of CAF (CAFYBB2022SY001, CAFYBB2018ZA001).