气候变化领域集成服务门户(CCPortal): Causes for the increase of early-season freezing events under a warmer climate at alpine Treelines in southeast Tibet

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DOI	10.1016/j.agrformet.2022.108863
	Causes for the increase of early-season freezing events under a warmer climate at alpine Treelines in southeast Tibet
	Shen, Wei; Zhang, Lin; Luo, Tianxiang
通讯作者	Luo, TX (通讯作者)
发表日期	2022
ISSN	0168-1923
EISSN	1873-2240
卷号	316
英文摘要	Few data have demonstrated why early-season freezing events may increase under a warmer climate at alpine treelines, which is critical to understand the key limiting factors determining treeline dynamics under future climate warming. Here we test the hypothesis that the increase of early-season freezing events under a warmer climate is mainly associated with advanced onset of growing season and enhanced radiative cooling effect in the pre-monsoon season. We conducted 11-year observations of microclimate factors across north-facing and southfacing treelines in the Sergyemla Mountains, southeast Tibet. We found that the frequency, intensity, and duration of early-season freezing events were generally higher under a warmer climate on the south-facing slope or in the warmer years within a slope, in which the frequency of early-season freezing events significantly increased with increasing annual mean air-temperature. During 2006-2016, the frequency, intensity and duration of early-season freezing events typically showed a negative correlation with the onset date of growing season, while their frequency was positively correlated with the early-season global radiation. In each of both slopes, global radiation was significantly higher and long-wave radiation balance was much more negative on days with daily minimum air-temperature (Tmin) < 0 C than with Tmin > 0 degrees C, indicating the generality of radiative cooling effect on early-season freezing events at high elevations. Our data support the hypothesis, revealing physical mechanisms for the increase of early-season freezing events with climate warming. The physical mechanisms should provide a general explanation for the topography-dependent pattern of tree species distribution and alpine treeline stability under climate warming in high mountainous regions like the Himalayas.
关键词	TREE SEEDLING ESTABLISHMENT SPRUCE-FIR FORESTS SOIL-TEMPERATURE LIMITING PHOTOSYNTHESIS SERGYEMLA MOUNTAINS RADIATION BALANCE VARIABILITY CLEAR REGENERATION STABILITY
英文关键词	Climate change; Freezing events; Global radiation; Long-wave radiation; Snow cover change; Soil temperature
语种	英语
WOS研究方向	Agriculture ; Forestry ; Meteorology & Atmospheric Sciences
WOS类目	Agronomy ; Forestry ; Meteorology & Atmospheric Sciences
WOS记录号	WOS:000796480700006
来源期刊	AGRICULTURAL AND FOREST METEOROLOGY
来源机构	中国科学院青藏高原研究所
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/260553
推荐引用方式 GB/T 7714	Shen, Wei,Zhang, Lin,Luo, Tianxiang. Causes for the increase of early-season freezing events under a warmer climate at alpine Treelines in southeast Tibet[J]. 中国科学院青藏高原研究所,2022,316.
APA	Shen, Wei,Zhang, Lin,&Luo, Tianxiang.(2022).Causes for the increase of early-season freezing events under a warmer climate at alpine Treelines in southeast Tibet.AGRICULTURAL AND FOREST METEOROLOGY,316.
MLA	Shen, Wei,et al."Causes for the increase of early-season freezing events under a warmer climate at alpine Treelines in southeast Tibet".AGRICULTURAL AND FOREST METEOROLOGY 316(2022).