1. Past rainfall reconstruction using speleothem from Nakarallu cave, Kadapa, Andhra Pradesh, India Naveen Gandhi, Nitesh Sinha, S. Chakraborty, H. P. Borgaonkar, M. G. Yadava and R. Ramesh

2. -1.5‰ /100 mm -0.22 ‰ / 0 C large changes in speleothem δ 18 O are mainly by variations in δ 18 O p

3. 3 Speleothem research in India Our site of study Regions studied so far

4. 4 Time periods covered so far Present- AD 4000 (Uttrakhand, Kotlia et al., 2014; QI) 15700-14700 BP (Kurnool, AP; Lone et al, 2014; PALAEO3) 11200-3670 BP (Meghalaya; Berkelhammer et al, 2012; AGU Monograph) Present-4000 BP (Andaman; Laskar et al, 2013; G3) Present-3400 BP (Chhattisgarh; Yadava and Ramesh 2005; The Holocence) AD 600-1500 (Chhattisgarh; Sinha et al, 2007; GRL) AD 1075-2008 (Chhattisgarh; Sinha et al, 2011; GRL) AD 1399-2007 (Shillong; Sinha et al, 2011; GRL) AD 1560-2006 (Uttarakhand; Kotlia et al, 2012; QI) AD 1666-1996 (Karnataka; Yadava et al, 2004; The Holocence)

5. Major findings so far Kotlia et al., 2014; Present-AD 4000 Central Himalaya influenced by ISM and westerlies Higher precipitation during 0.5-0.25 ka BP (part of LIA) due to strong westerlies Driest period ~3.2 ka BP Lone et al, 2014; 15700-14700 BP Abrupt change in ISM during the last deglaciation Onset of T1a at 1480 BP in the Indian subcontinent Strong monsoon during later phase of H1 Berkelhammer et al, 2012; 11200-3670 BP ISM weakened during 4071-3670 BP and remained in the state for almost 180 years Laskar et al, 2013; Present-4000 BP Strongest ISM activity during MWP (800-1200 BP) Decreasing trend in ISM in the transition from MWP to LIA Small reductions in ISM around 1500 and 450-800 BP Yadava and Ramesh 2005; 0-3400 BP 14 years arid phase around 2000 BP Higher than present ISM activity at 600 BP An arid phase observed before 1200 BP Continue….

6. Sinha et al, 2007; AD 600-1500 Monsoon weakened during 14 th and mid 15 th century Sinha et al, 2011; AD 1075-2008; AD 1399-2007 Intra-seasonal variability of ISM produces quasi east-west precipitation dipole (enhanced-deficient) over the Indian sub- continent Precipitation in central and NE India oscillating between periods of active (AD 1700-2007) and break (AD 1400-1700) dominated regimes. The abrupt switch was at AD 1650-1700. Kotlia et al, 2012; AD 1590-2006 LIA (AD 1590-1850) and post LIA (after AD 1850) were mostly wet and dry periods, respectively. Yadava et al, 2004; AD 1666-1996 Highest rainfall ~ AD 1666 and lowest rainfall ~AD 1900 in the period AD 1666-1996

7. Sampling site: Kadapa, Andhra Pradesh, INDIA

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9. 9 Sample232Th238UU/Th AN14-06-59-NK1305-0010.477716.5 218550 AN14-06-60-NK1305-01016.97776 460 AN14-06-61-NK1305-0140.862084.2 73420 AN14-06-62-NK1305-0230.866159 83313 AN14-06-63-NK1305-0330.45229.1 13819 AN14-06-64-NK1305-0401.551990.1 35334 AN14-06-65-NK1305-0460.320206.6 58132 AN14-06-66-NK1305-0520.944851.2 51171 AN14-06-67-NK1305-0540.65980 10740 AN14-06-68-NK1305-0610.84038.6 5367 AN14-06-69-NK1305-0641.53856.7 2541 AN14-06-70-NK1305-0702.54471.9 1783 AN14-06-71-NK1305-0774.68928.6 1938 AN14-06-72-NK1305-0850.35410.5 20963 AN14-06-73-NK1305-0904.25753 1361 AN14-06-74-NK1305-0930.54870.9 10263 AN14-06-75-NK1305-0960.14618.7 32030 AN14-06-76-NK1305-1086.15159.7 847 AN14-06-77-NK1305-1136.75278.2 785 AN14-06-78-NK1305-1332.25183.9 2401 AN14-06-79-NK1305-1420.23397.2 22204 AN14-06-80-NK1305-1530.34925.3 14880 AN14-06-81-NK1305-1680.45653.8 16140 AN14-06-82-NK1305-1740.2197.1 1225 AN14-06-83-NK1305-1852.149 23 AN14-06-84-NK1305-1870.3164.2 616 AN14-06-85-NK1305-1991.84838.1 2625 AN14-06-86-NK1305-2095.74707.1 827

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11. Speleothem Sample Analysis Sample Cross-Section of the Sample Weighing (~100 µg) Preparation of 100% pure H 3 PO 4 Commercially 98% pure is available Add P 2 O 5 and heat (180 o C) for 2-3hrs Leave it for over night (120 o C) Transfer to the bottle immediately to reduce the chance of getting moisture Adding acid to the sample Ortho-Phosphoric Acid (H 3 PO 4 )

12. 12 δ 13 C and δ 18 O variations with radiocarbon ages

13. 13 (Yadava et al., 2005) (Laskar et al., 2013) Baratang cave Point to notice: Resolution Spatial Variation Calibration Scales are inverse Kadapa Cave

14. 14 Stalactite from Bitto cave, Uttrakhand, INDIA

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16. Thank You