Biomass-Derived Provenance Dominates Glacial Surface Organic Carbon in the Western Himalaya.

The origin, transport pathway, and spatial variability of total organic carbon (OC) in the western Himalayan glaciers are poorly understood compared to those of black carbon (BC) and dust, but it is critically important to evaluate the climatic role of OC in the region. By applying the distribution of OC activation energy; 14C activity; and radiogenic isotopes of 208Pb/204Pb, 207Pb/204Pb, and 206Pb/204Pb in glacial debris and atmospheric particulate matter (PM10 size fraction), we demonstrate that 98.3 ± 1.6 and 1.7 ± 1.6% of OC in western Himalayan glaciers are derived from biomass and petrogenic sources, respectively. The δ13C and N/C composition indicates that the biomass is a complex mixture of C3 vegetation and autochthonous photoautotrophic input modified by heterotrophic microbial activity. The data set reveals that the studied western Himalayan glacier has negligible contributions from fossil-fuel-derived particles, which contrasts to the central and eastern Himalayan glaciers that have significant contributions from fossil fuel sources. We show that this spatial variability of OC sources relates to regional differences in air mass transport pathways and precipitation regimes over the Himalaya. Moreover, our observation suggests that biomass-derived carbon could be the only primary driver of carbon-induced glacier melting in the western Himalaya.

Rapid urbanization and associated impacts on land surface temperature changes over Bhubaneswar Urban District, India.

Urban settlements are the socio-economic drivers of human community. However, rapid urban expansion during recent times has a profound effect on regional as well as global rise in temperatures. Remote sensing is a powerful tool to monitor and quantify the expansion of urban built-up area and assess its effects on regional heating. Landsat-derived Land Use Land Cover (LULC) maps have shown a very rapid urbanization in Bhubaneswar, a tier-2 city and the capital of Odisha in the eastern part of India, almost doubling over the last 15 years. Our study on the effects of urbanization reveals that during the period of 2003-2017, the built-up area in the urban district of Bhubaneswar has increased by about 77% at the cost of natural vegetative cover and agricultural/fallow land. This affects the behavior of several climate variables over the urban centers with a clear distinction in these variables observed between the urban and surrounding rural settlements. Land surface temperature (LST) derived from the thermal bands of Landsat satellites at a spatial resolution of 30 m is used for the analysis over the area of interest. The Bhubaneswar airport (urban reference) has shown an increase in mean summer LST by 8% over the study period of 15 years, and 9.84% in LST in the last 5 years from 2013 to 2017 alone. From the present study, it is inferred that it is essential to adopt a sustainable approach for any urban growth to restrain its effect on urban temperature rise.