Temperature trends and elevation dependent warming during 1965 – 2014 in headwaters of Yangtze River, Qinghai Tibetan Plateau Temperature trends and elevation dependent warming during 1965 – 2014 in headwaters of Yangtze River, Qinghai Tibetan Plateau

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Vol17 No.3: 556-571

Title】Temperature trends and elevation dependent warming during 1965 – 2014 in headwaters of Yangtze River, Qinghai Tibetan Plateau

Author】Naveed AHMED1,2, WANG Gen-xu1*, Adeyeri OLUWAFEMI3, Sarfraz MUNIR4, HU Zhao-yong1,2, Aamir SHAKOOR5, Muhammad Ali IMRAN6

Addresses】1 Key Laboratory of Mountain Surface Process and Ecological Regulations, Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu 610041, China; 2 University of Chinese Academy of Sciences, Beijing 100049, China; 3 Institute for Meteorology and Climate Research Atmospheric Environmental Research, Karlsruhe Institute of Technology, Campus Alpine, 82467, Germany; 4 Water Resources Engineering University of Kurdistan Hewler 30 Meter Avenue, Erbil, Kurdistan, 44001, Iraq; 5 Department of Agricultural Engineering, Bahauddin Zakariya University, Multan, 66000, Pakistan; 6 Beijing Key Laboratory of Water Resources and Environmental Engineering, China University of Geosciences, Beijing 100083, China

Corresponding author】WANG Gen-xu

Citation】Ahmed N, Wang GX, Oluwafemi A, et al. (2020) Temperature trends and elevation dependent warming during 1965 – 2014 in headwaters of Yangtze River, Qinghai Tibetan Plateau. Journal of Mountain Science 17(3). https://doi.org/10.1007/s11629-019-5438-3

DOI】https://doi.org/10.1007/s11629-019-5438-3

Abstract】The understanding of temperature trends in high elevation mountain areas is an integral part of climate change research and it is critical for assessing the impacts of climate change on water resources including glacier melt, degradation of soils, and active layer thickness. In this study, climate changes were analyzed based on trends in air temperature variables (Tmax, Tmin, Tmean), and Diurnal Temperature Range (DTR) as well as elevation-dependent warming at annual and seasonal scales in the Headwaters of Yangtze River (HWYZ), Qinghai Tibetan Plateau. The Base Period (1965-2014) was split into two sub-periods; Period-I (1965-1989) and Period-II (1990-2014) and the analysis was constrained over two sub-basins; Zhimenda and Tuotuohe. Increasing trends were found in absolute changes in temperature variables during Period-II as compared to Period-I. Tmax, Tmin, and Tmean had significant increasing trends for both sub-basins. The highest significant trends in annual time scale were observed in Tmin (1.15°Cdecade-1) in Tuotuohe and 0.98°Cdecade-1 in Zhimenda sub-basins. In Period-II, only the winter season had the highest magnitudes of Tmaxand Tmin 0.58°Cdecade-1 and 1.26°Cdecade-1 in Tuotuohe sub-basin, respectively. Elevation dependent warming analysis revealed that Tmax, Tmin and Tmean trend magnitudes increase with the increase of elevations in the middle reaches (4000 m to 4400 m) of the HWYZ during Period-II annually. The increasing trend magnitude during Period-II, for Tmax, is 1.77, 0.92, and 1.31°Cdecade-1, for Tmin 1.20, 1.32 and 1.59°Cdecade-1, for Tmean 1.51, 1.10 and 1.51°Cdecade-1at elevations of 4066 m, 4175 m and 4415 m respectively in the winter season. Tmean increases during the spring season for > 3681 m elevations during Period-II, with no particular relation with elevation dependency for other variables. During the summer season in Period-II, Tmax, Tmin, Tmean increases with the increase of elevations (3681 m to 4415 m) in the middle reaches of HWYZ. Elevation dependent warming(EDW), the study concluded that magnitudes of Tmin are increasing significantly after the 1990s as compared to Tmax in the HWYZ. It is concluded that the climate of the HWYZ is getting warmer in both sub-basins and the rate of warming was more evident after the 1990s. The outcomes of the study provide an essential insight into climate change in the region and would be a primary index to select and design research scenarios to explore the impacts of climate change on water resources.

Keywords】Climate change; Elevation dependent warming; Mann Kendall; Temperature trends; Yangtze River; Qinghai Tibetan Plateau