High-resolution millennial and centennial scale Holocene monsoon variability in the Higher Central Himalayas

Relict lake sediments situated within the transition of the lesser and higher central Himalayas show a persistent millennial to centennial-scale monsoon variability during the Holocene. Based on high resolution geochemical data supported by radiocarbon dating, six phases of enhanced Indian Summer Monsoon (ISM) with varying magnitude have been identified. These are dated between 10,000-9600, 9500-9200, 8600-5800, 5000-4200, 3500-2400 and 1800-1000 cal yr BP. The millennial and multi-centennial-scale phases of enhanced ISM are broadly comparable with the existing continental and marine records from the monsoon dominated region of SE Asia, suggesting sensitivity of the regions to short-term climatic perturbations. Further, the study observed that the phases of weakened ISM largely correlate with the drift-ice record of the northern Atlantic implying a coupling between short-term solar irradiance induced glacial boundary condition in the northern Atlantic and the millennial and multi-centennial scale monsoon variability in the central Himalaya

InSAR and GPS measurements of crustal deformation due to seasonal loading of Tehri reservoir in Garhwal Himalaya, India

We report unique observations of crustal deformation caused by the seasonal water level changes of Tehri reservoir in the Garhwal region ofNWHimalaya from GPS measurements and Interferometric Synthetic Aperture Radar (InSAR) analysis. All GPS sites along the Himalaya are strongly influenced by seasonal hydrological and atmospheric loading. However, the GPS siteKUNRlocated near the reservoir additionally exhibits anomalous variations due to seasonal water loading and unloading by the reservoir. Our InSAR analysis confirms that the seasonal filling of the reservoir causes measurable subsidence in its neighbourhood. In addition to the elastic deformation caused by the seasonal reservoir loading and the negligible poroelastic deformation caused by associated fluid pressure changes, there is an unaccounted biannual deformation in the east component of the GPS time-series which we suspect to be caused by altered hydrological conditions due to the reservoir operations. Understanding crustal deformation processes due to such anthropogenic sources helps in separating deformation caused by tectonic, hydrological and atmospheric effects from that caused by these activities

Analysis of weather- and climate-related disasters in mountain regions using different disaster databases

Mountains are fragile ecosystems with global importance, providing key ecosystems services within mountainous areas but also for the lowlands. However, mountain regions are prone to natural disasters and exposed to multiple hazards. In this chapter, we present four disaster databases (EM-DAT, NatCatSERVICE, DesInventar, Dartmouth) that store information about spatiotemporal occurrence and impacts of natural disasters in mountain areas. Quality and completeness of the four databases are compared and analyzed regarding reliability for weather- and climate-related natural disasters. The analysis identifies the numbers of fatalities as the most reliable loss parameters, whereby the number of people affected and the economic loss are less trustworthy and highly dependent on the purposes of each database. Main limitations regarding sustainable mountain development are the inhomogeneity in database definitions, spatial resolutions, database purposes and lack of data registration for human and economic losses. While some individual disasters such as the Kedarnath flood in northern India in 2013 have been robustly linked to changes in climate, there is generally insufficient evidence to attribute any overall increasing disaster frequency to climate change. Damage due to hazard in mountain regions will increase irrespective of global warming, in regions where populations are growing and infrastructure is developed at exposed locations