Transcript Pre-monsoon precipitation signal in tree rings of timberline Betula

Pre-monsoon precipitation signal in tree rings
of timberline Betula utilis in the Central Himalayas
1,2Binod
Dawadi, 2Eryuan Liang
1Central
Department of Hydrology and Meteorology,
Tribhuvan University, Kathmandu, Nepal
2Institute of Tibetan Plateu Research,
Chinese Academy of Sciences, Beijing
e-mail: [email protected]
19 March, 2015
Tree-ring studies in Himalayan and surrounding region
Indian Himalaya (Western and Eastern Himalaya)
 Temperature reconstruction: Yadav et al. (1997); Borgaonkar et al.
(1996); Pant et al. (1998); Yadav et al. (1999); Yadav and Singh (2002);
Bhattachryya and Chaudhary (2003),Yadav et al (2011) etc.
 Precipitation reconstruction: Yadav and Park (2000); Singh and
Yadav (2005); Singh et al. (2006); Singh et al. (2009); Yadav (2011a); Yadav
(2011b) etc.
Studies from Karakoroum/Tien Shan Mt range of Pakistan
Ahmed,M (1989); Ahmed,M (1991); Ahmed, et al (2009) Ahmed et al (2011);
Esper et al.(1995); Esper J.(1995); Esper et al.(2001); Esper et al.(2002); Esper
et al.(2003); Esper et al.(2007); Khan et al.(2008) etc.
Dendroclimatological studies from Tibetan Plateau
Precipitation reconstruction
 Zhang and Wu 1997; Gou et al. 2001; Kang et al. 2002; Qin et al.
2003; Zhang et al. 2003; Sheppard et al. 2004; Shao et al. 2005;
Huang and Zhang 2007; Liu et al. 2006; Yin et al. 2008 etc.
 Temperature reconstruction:
Shao and Fan 1999; Bräuning and Mantwill 2004; Liu et al. 2005;
Gou et al. 2007; Fan et al. 2008; Liang et al. 2008; 2009, 2008;
Zhu et al. 2008, 2011 etc.
 .
Dendrochronological studies in Nepal
Sano et al 2005
Thapa et al 2014
Cook et al 2003
[Suzuki(1990); Bhattachryya et al.(1992); Cook et al.(2003);Sano et al.(2005);
Sano et al. (2009): Sano et al. (2011), Gaire et al (2012), Dawadi et al 2013, 2013, Liang et al
2014, Gaire et al 2014, Thapa et al 2014].
Studied species: Abies spectabilis,Pinus roxburgii,Pinus wallichiana,Tsuga dumosa,
Picea smithiana,Juniperus recurva,Ulmus wallichiana,Larix potanini , Cupressus
torulosa
Reconstructed temperature in Nepal
Cooling
AD1790-1810
1950- 2000
Sano et al., 2005
Tambora in 1815–1816
Cooling from 1960s to 1991
late-20th century warming,
Cook et al.,(2003)
Multi-decadal to century-scale warming and cooling trends are matching.
Reconstructed temperature in Nepal
Thapa et al 2014
Different than Cook et al 2003 and Sano et al 2005, may be due to the
Reconstructed month/ season
Some gaps Dendrochroclimatological study in Central Himalaya
 Suzuki E (1990) and Bhhatachrrya et al. (1992)
 Did not find tree-ring climate correlation, why?
 Cook et al (2003)
 They covered wide area from elevation 1830-3630m but most
of the samples were not from treeline/Timberline.
 In spite of wide distribution of Himalayan birch in the high
Asia from Afghanistan, Pakistan, India, Nepal, Bhutan,
Southern China, Myanmar, why there is very a few
dendrochronological studies on this species ?
 Not only in Asia why there is a few studies on Himalayan
birch worldwide?
Objectives
 To investigate the dendroclimatic potentiality of Himalayan
birch (betula Utilis)
 To develop long tree-ring chronology from Nepal
 To study the tree-ring based climate change from the tree ring
of central Nepal
Sampling Area
Where: Central Himalaya, Nepal, Around 4000 m sal.
How many sites: 4 sites but only 2 sites are used
Sampling Place: Kaynjing ( LT1) & Langtang Village ( LT4)
How many samples: 19 (23) LT1 & 23 (26) from LT4
Kyangjing
Langtang National Park
Landscape of
the sampling
site
Kyanjing
Birch trees near by Kaynjing
Clear Ring-width of Himalayan birch
When moisten rings are clearly
visible and easy to cross date
Result and discussion
(a)
2.4
50
2
40
30
1.2
20
0.8
10
0.4
0
0
1550
1600
1650
1700
1750
1800
1850
(b)
0.3
1950
2000
EPS
0.9
EPS=0.85
0.25
0.2
RBAR
1900
0.8
RBAR
0.15
0.7
0.1
0.6
0.05
0
0.5
1550
1600
1650
1700
1750
1800
1850
1900
1950
Fig (a) Tree-ring width chronology with its 9 year moving average curve (thick solid line)
and sample depth (dashed line)
(b) Variation of RBAR and EPS over time.
2000
EPS
Ring Index
1.6
Sample depth
41 trees, 49 cores, 458 Year Chronology (1552-2009)
Results and discussion
Parameters
Duration/value
Chronology time span (year)
1552-2009 (458)
Mean sensitivity
0.19
Standard deviation
0.23
First-order autocorrelation
0.45
Expressed population signal*
0.93
Signal-to-noise ratio*
12.87
Variance in first eigenvector*
30%
Correlation among all radii*
0.26
* for the common interval from 1900-2000.
Correlation between Climate and RI
Ring index of Himalayan birch showed Positive correlation with
Pre-monsoon precipitation and inverse relation with temperature
Results and discussion
 Elevation-dependent precipitation: Pre-monsoon precipitation
at Kyangjing (3,950 meter)- 94 mm.
 Under very strong solar radiation at high elevation,
temperature could increase drought stress by enhancing evapotranspiration, resulting in a negative correlation between tree
growth and the mean March-May temperature, as reported by
Liang et al. (2012).
 The similar response of most of the conifers from the
Himalayan region: (Sano et al., 2005; Singh et al., 2009;
Borgaonkar et al., 2011; Yadav, 2011) and inverse with
temperature (Borgaonkar et al., 1996; Yadav et al., 2004)
Results and discussion contd
Occurrence of Missing rings in the extreme dry Year
25
Missing rings were dated well
1995 (7.8%)
1999 (13.5%)
2003 (23.6%)
2004 (22.0%)
Percentage of missing rings
1954 (5.8%)
20
15
10
5
0
1800
1850
1900
1950
2000
Year
The 2003,2004 and 1999 are the years with extreme pre monsoonal drought
condition in South Asia including Nepal (Sigdel and Ikeda 2009; WMO 2011).
LT4- South west facing slope produced higher frequency of missing rings than LT1.
High percentage of missing rings in the extreme drought year confirmed the
growth of Himalayan birch was drought sensitive
Results and discussions contd..
(1998-2011)
Decrease in precipitation beyond certain elevation
Namche bazar (3400m)- 1000mm (Miehe et al. 2007), Pyramid (5050m)- 465mm (Bollasina et al. 2002),
Khumbu glacier (5300m)- 450mm( Dhara and Nandargi, 2000 )
Results and discussion contd
WMO, 2011
(Cook et al 2010)
East Indian drought
(1796-1798)
Other Megha drought 1560s
Islam & Das 2009
Late Victorian great drought
Shakya &Yamaguchi 2007
(1876-1878)
Strange Parallels drought
(1756-1768)
Attri and Tyagi 2010
Regional historical drought
Sigdel & Ikeda 2010
2.4
Singh et al. 2009;Yadav 2011
2.0
Tree-ring based precipitation
Instrumental/
Satellite
Conclusion
 Developed a 458-year chronology of Himalayan birch, the longest
chronology of this species till date.
 The chronology statistics showed its potentiality for dendroclimatic
studies.
 The climate and tree growth relationships demonstrated that the
growth of Himalayan birch was an excellent proxy of March-May
precipitation.
 .Tree-ring captured most of the local and regional drought events.
 Himalayan birch from the central Himalayas can be use for the
reconstruction of pre-monsoon precipitation