Abstract
Knowledge about the dynamics and biophysical controlling mechanism of nocturnal evapotranspiration (ETN) in desert-dwelling shrub ecosystem is still lacking. Using the eddy covariance measurements of latent heat flux in a dried shrubland in northwest China, we examined the dynamics of ETN and its biophysical controls at multiple timescales during growing-seasons from 2012 to 2014. The ETN was larger in the mid-growing season (usually in mid-summer) than in spring and autumn. The maximum daily ETN was 0.21, 0.17, and 0.14 mm night−1 in years 2012–2014, respectively. At the diel scale, ETN decreased from 21:00 to 5:00, then began to increase. ETN were mainly controlled by soil volumetric water content at 30 cm depth (VWC30), by vapor pressure deficit (VPD) and normalized difference vegetation index (NDVI) at leaf expanding and expanded stage, and by air temperature (Ta) and wind speed (Ws) at the leaf coloring stage. At the seasonal scale, variations of ETN were mainly driven by Ta, VPD, and VWC10. Averaged annual ETN was 4% of daytime ET. The summer drought in 2013 and the spring drought in 2014 caused the decline of daily evapotranspiration (ET). The present results demonstrated that ETN is a significant part of the water cycle and needs to be seriously considered in ET and related studies. The findings here can help with the sustainable management of water in desert ecosystems undergoing climate change.
Highlights
Water is lost from the land surface to the atmosphere through evapotranspiration (ET) [1]
An increasing number of studies have demonstrated the occurrence of nocturnal evapotranspiration (ETN ), with the estimation of nocturnal transpiration (TN ) from the plant, which have the nighttime stomatal opening found in many species around the world [1,3,4]
Annual rainfall was highest in 2014 and lowest in 2013 (Table 1). It seems that VWC10 was more affected by rainfall events which were less than 20 mm day−1 and
Summary
Water is lost from the land surface to the atmosphere through evapotranspiration (ET) [1]. This process interlinks the water, energy, and carbon cycles and influences climate, ecology, agriculture, and the economy [1,2]. An increasing number of studies have demonstrated the occurrence of nocturnal evapotranspiration (ETN ), with the estimation of nocturnal transpiration (TN ) from the plant, which have the nighttime stomatal opening found in many species around the world [1,3,4]. The global prediction is that the opening of stomata and water loss at night increases transpiration, inhibits carbon increase, and exacerbates soil hydrological drought [3,7]. The regulation mechanism of ETN is not fully understood, especially in dry areas [3,7]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
