https://orcid.org/0000-0002-9487-7852
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ABSTRACT
Tree rings are widely used to reconstruct past climates in regions where observational records of climate are short. In this study, we developed a 294 years-long (1718–2011 CE) ring-width chronology of the Himalayan Silver fir (Abies spectabilis (D.Don, Spach)) from Humla district in western Nepal to reconstruct winter minimum temperature for the remote region of central Himalaya where instrumental records are limited to past three or four decades. Ring-width chronology of the Himalayan Silver fir showed strongest and significant positive correlation with minimum winter temperature prior to the growing season. Based on this relationship, we reconstructed the winter season (previous October–current February) minimum temperature for western Nepal covering the period of 1780–2008 CE. Our reconstruction showed that winter minimum temperature is continuously increasing since the early twentieth century with unprecedented rapid warming in the latter half. The cold episodes in the reconstruction coincided with the major volcanic eruptions in the Northern Hemisphere and tropical regions. The spectral analysis using Multi-Taper Method revealed that the winter temperature in the north-western Himalaya has short- to medium-term periodicities of 2–3, 5.8–6.2, 7.9–8.2, 39–46 and 56–73 years, which suggest possible teleconnections with ENSO (El-Nino Southern Oscillation) and AMO (Atlantic Multidecadal Oscillation).
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Acknowledgements
This study was jointly supported by National Natural Science Foundation of China (31770533, 31861133007 to Z-XF); Institutional support of Czech Academy of Sciences (GAČR 17-10280S and RVO 67985939 to MBR) and Yunnan Oriented Fund for Post Doctors and The CAS President’s International Fellowship Initiative’ (PIFI) postdoctoral fellowship (2019PC0102 to NPG). Meteorological data were obtained from the Department of Hydrology and Meteorology in Nepal. We thank local field assistants for their support during sample collection. We are grateful to two anonymous reviewers and an associate editor for their valuable comments and suggestion in the previous version of this manuscript. NPG and MBR conceived and designed the study. MBR collected samples. NPG, Z-XF, SKS and UKT carried out analyses. NPG, Z-XF and SKS wrote the manuscript; all authors read, edited and approved final version.
Disclosure statement
No potential conflict of interest was reported by the author(s).
Notes on contributors
Narayan Prasad Gaire is a Post-Doc fellow at Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences. He is doing research in the areas of treeline dynamics and past climate reconstructions in the Nepal Himalaya. His research interests include forest ecology, climate change, dendrochronology and climatic reconstruction.
Ze-Xin Fan is a Professor at Xishuangbanna Tropical Botanical Garden (XTBG), Chinese Academy of Sciences. He is the PI of the Tree-Ring and Environmental Change Group in XTBG. He is doing research about forest ecology, dendroecology and dendroclimatology in Hengduan Mountains and Himalayas for past two decades. He is the member of Yunnan Ecological Association, Asian Dendrochronology Association and China Dendrochronology Association. He is the review editor of Plant Diversity and Frontiers in Plant Science.
Santosh Kumar Shah is a Scientist at Birbal Sahni Institute of Palaeosciences, Lucknow, India. He is dedicated in Spatio-temporal temperature and hydroclimate reconstruction using tree-rings, climate field reconstruction, palaeo vegetation and climate using palynology. He also performs temporal and spatial multivariate statistical analysis. His main research focus area is Himalayas and tropical regions of India.
Uday Kunwar Thapa is a doctoral candidate and graduate fellow at the University of Minnesota’s Department of Geography, Environment and Society. Mr Thapa is a physical geographer and environmental scientist who investigates long-term changes in climate and forest growth in the Himalayan regions using information preserved in the annual growth layers of trees. His work also utilizes the science of dendrochronology to examine the competing effects of climate and humans on forest health.
Man Bahadur Rokaya is a scientist at the Institute of Botany, Czech Academy of Sciences. Dr Rokaya’s research mainly focused on forest ecology, environmental change and its impacts in the Himalayas.