| Variability of Pre-monsoon precipitation inferred from Himalayan Birch from the Mt Everest region, Central Himalaya |
| Paper ID : 1031-ADA2013 |
| Authors: |
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Binod Dawadi *1, Eryuan Liang2 1PO Box 2871, 4A Datun Road,
Chaoyang District, Beijing 100101, China 24A, Datun Rd., Chaoyang district, Beijing 100101 |
| Abstract: |
| Based on 163 cores of 113 Himalayan Birch from Sagarmatha national park (4 sites) (86.75E, 27.85N, ~4000 m asl.) and Kyangjing of Langtang National park (85.56E, 28.20N, ~4100m asl), we developed 460-year tree-ring width chronology of Himalayan Birch from the central Himalaya, Nepal. This is the longest chronology of this species yet produced from the Himalaya. The chronological statistics, such as mean sensitivity and correlation between tree-ring series showed its high potentiality for the dendroclimatological study. The radial growth of Himalayan Birch records clear climatic signals as indicated by positive correlation with precipitation of March, May and pre-monsoon season (March-May) (r= 0.57, n= 60, p <0.0001). This chronology showed extremely narrow rings in the local, regional and global drought periods as recorded by instrumental and proxy sources such as tree rings and ice cores studies. The well-documented historical megadroughts, such as the Strange Parallels drought (1756-1768) and the East India drought (1790-1796) appear to be embedded in much longer drought periods in this series. In this context, the persistent pre-monsoon droughts in the central Himalayas seem to be harbingers of the megadroughts induced by the South Asian monsoon failure. Himalayan Birch growth is positively correlated with Palmer Drought Severity Index (PDSI) variability over Nepal. All the months showed statistically significant (p < 0.05) positive correlation. Correlations are strongest for the month of March, April and May (r= 0.35, p <0.0001, n=135), reflecting the importance of moisture availability for Himalayan Birch’s growth in the pre-monsoon season. In addition, this record also correlates significantly with larger-scale climate indices, including core Indian rainfall for pre-monsoon season (MAM) r= 0.28, p <0.03, n=57. The correlations slightly improve using data for northern regions of India. For east Uttar Pradesh, North central India and north mountain region of India the correlations are r= 0.31, p <0.01, r= 0.30, p <0.03, and r= 0.31, p <0.02, respectively over the period of 1950-2006, indicating a teleconnection between ring indices from central Himalaya and regional climate series. |
| Keywords: |
| Climate change; Central Himalaya; Precipitation Variation; Tree-ring;Betula |
| Status : Abstract Accepted |
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