TY  - JOUR
A1  - Mishra, Praveen Kumar
A1  - Prasad, Sushma
A1  - Marwan, Norbert
A1  - Anoop, A.
A1  - Krishnan, R.
A1  - Gaye, Birgit
A1  - Basavaiah, N.
A1  - Stebich, Martina
A1  - Menzel, Philip
A1  - Riedel, Nils
T1  - Contrasting pattern of hydrological changes during the past two millennia from central and northern India
BT  - regional climate difference or anthropogenic impact?
JF  - Global and planetary change
N2  - High resolution reconstructions of the India Summer Monsoon (ISM) are essential to identify regionally different patterns of climate change and refine predictive models. We find opposing trends of hydrological proxies between northern (Sahiya cave stalagmite) and central India (Lonar Lake) between 100 and 1300 CE with the strongest anti-correlation between 810 and 1300 CE. The apparently contradictory data raise the question if these are related to widely different regional precipitation patterns or reflect human influence in/around the Lonar Lake. By comparing multiproxy data with historical records, we demonstrate that only the organic proxies in the Lonar Lake show evidence of anthropogenic impact. However, evaporite data (mineralogy and delta O-18) are indicative of precipitation/evaporation (P/E) into the Lonar Lake. Back-trajectories of air-mass circulation over northern and central India show that the relative contribution of the Bay of Bengal (BoB) branch of the ISM is crucial for determining the delta O-18 of carbonate proxies only in north India, whereas central India is affected significantly by the Arabian Sea (AS) branch of the ISM. We conclude that the delta O-18 of evaporative carbonates in the Lonar Lake reflects P/E and, in the interval under consideration, is not influenced by source water changes. The opposing trend between central and northern India can be explained by (i) persistent multidecadal droughts over central India between 810 and 1300 CE that provided an effective mechanism for strengthening sub-tropical westerly winds resulting in enhancement of wintertime (non-monsoonal) rainfall over northern parts of the Indian subcontinent, and/or (ii) increased moisture influx to northern India from the depleted BoB source waters.
KW  - ENSO
KW  - Isotopes
KW  - Indian summer monsoon
KW  - Lonar Lake
KW  - Stalagmites
KW  - Westerlies
Y1  - 2017
U6  - https://doi.org/10.1016/j.gloplacha.2017.12.005
SN  - 0921-8181
SN  - 1872-6364
VL  - 161
SP  - 97
EP  - 107
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Malik, Nishant
A1  - Bookhagen, Bodo
A1  - Marwan, Norbert
A1  - Kurths, Jürgen
T1  - Analysis of spatial and temporal extreme monsoonal rainfall over South Asia using complex networks
JF  - Climate dynamics : observational, theoretical and computational research on the climate system
N2  - We present a detailed analysis of summer monsoon rainfall over the Indian peninsular using nonlinear spatial correlations. This analysis is carried out employing the tools of complex networks and a measure of nonlinear correlation for point processes such as rainfall, called event synchronization. This study provides valuable insights into the spatial organization, scales, and structure of the 90th and 94th percentile rainfall events during the Indian summer monsoon (June-September). We furthermore analyse the influence of different critical synoptic atmospheric systems and the impact of the steep Himalayan topography on rainfall patterns. The presented method not only helps us in visualising the structure of the extreme-event rainfall fields, but also identifies the water vapor pathways and decadal-scale moisture sinks over the region. Furthermore a simple scheme based on complex networks is presented to decipher the spatial intricacies and temporal evolution of monsoonal rainfall patterns over the last 6 decades.
KW  - Indian summer monsoon
KW  - Event synchronization
KW  - Complex networks
KW  - Rainfall patterns
Y1  - 2012
U6  - https://doi.org/10.1007/s00382-011-1156-4
SN  - 0930-7575
VL  - 39
IS  - 3-4
SP  - 971
EP  - 987
PB  - Springer
CY  - New York
ER  -