Strong seasonal connectivity between shallow groundwater and soil frost in a humid alpine meadow, northeastern Qinghai-Tibetan Plateau

NWIPB OpenIR

	Strong seasonal connectivity between shallow groundwater and soil frost in a humid alpine meadow, northeastern Qinghai-Tibetan Plateau
	Zhang, Fawei; Li, Hongqin; Li, Yikang; Guo, Xiaowei; Dai, Licong; Lin, Li; Cao, Guangmin; Li, Yingnian; Zhou, Huakun
	2019
发表期刊	JOURNAL OF HYDROLOGY
卷号	574
摘要	The freeze-thaw cycle in the active soil layer plays a crucial role in cold-region hydrological processes, yet the effect of vertical water migration caused by the soil frost on shallow groundwater remains poorly quantified. The shallow groundwater level (GWL), soil frost depth and main environmental controls were monitored in a humid alpine meadow on the northeastern Qinghai-Tibetan Plateau from 2012 to 2017. GWL fluctuated with two seasonal maxima and minima during soil frost-centric year from November to October. GWL declined remarkably from the strong peak (3.9 +/- 0.2 m, Mean +/- S.D.) in mid-January to the strong minimum (4.8 +/- 0.1 m) in mid-May, and then increased to the second peak (4.2 +/- 0.2 m) in late August. This seasonal variability in GWL was mainly attributed to the freeze-thaw processes of the lower layer soil frost from November to late June both at a similar to 45-day delay, respectively. The clear increasing GWL from mid-November to mid-January was probably related to the melted upper layer soil frost, which was detained in subsoil layers because of the high thermal isolating effect in topsoil Mattic Epipedon (dense organic-rich turf) and the associated negative subsoil profile temperature gradient from mid-May to late August. The seasonal N-type in GWL was thus hysteretically determined by the soil freeze-thaw processes and the related subsoil profile temperature gradient. Annually, GWL was significantly correlated with air temperature (R-2 = 0.88, P = 0.003, N = 6), suggesting the shallow groundwater recharges would be weakened under the warming scenario. Annual GWL was not directly connected with annual precipitation (P = 0.81), likely owing to the high water holding capacity of the topsoil Mattic Epipedon and the similarity between precipitation input and evapotranspiration loss. This critical buffering function of the topsoil Mattic Epipedon in vertical moisture movement should be taken into consideration when modeling regional water dynamics in humid alpine meadows.
关键词	Shallow groundwater table Soil frost Freeze-thaw processes Mattic Epipedon Qinghai-Tibetan Plateau
文献类型	期刊论文
条目标识符	http://210.75.249.4/handle/363003/59754
专题	中国科学院西北高原生物研究所
推荐引用方式 GB/T 7714	Zhang, Fawei,Li, Hongqin,Li, Yikang,et al. Strong seasonal connectivity between shallow groundwater and soil frost in a humid alpine meadow, northeastern Qinghai-Tibetan Plateau[J]. JOURNAL OF HYDROLOGY,2019,574.
APA	Zhang, Fawei.,Li, Hongqin.,Li, Yikang.,Guo, Xiaowei.,Dai, Licong.,...&Zhou, Huakun.(2019).Strong seasonal connectivity between shallow groundwater and soil frost in a humid alpine meadow, northeastern Qinghai-Tibetan Plateau.JOURNAL OF HYDROLOGY,574.
MLA	Zhang, Fawei,et al."Strong seasonal connectivity between shallow groundwater and soil frost in a humid alpine meadow, northeastern Qinghai-Tibetan Plateau".JOURNAL OF HYDROLOGY 574(2019).