Determining the quasi monsoon front in the Indian Himalayas

Precipitation over the southern rim of Indian Himalayan Region (IHR) mainly occurs due to two dominant synoptic weather systems: winter (IWM: December, January, February) and summer monsoon (ISM: June, July, August, September). The genesis evolution these systems are extensively researched. Additionally, geographical location, season, orography controls strengths along across IHR. However, plausible positioning frontal threshold limit precipitation during IWM ISM IHR remains an elusive scientific question. Thus, with help water samples collected in upper Bhilangana River Basin (BRB central Himalayas), attempt has been made assess this is defined as “quasi front (QMF)" Results show depleted (enriched) stable isotopic values at higher (lower) altitudes suggesting elevation control. intercepts local meteoric lines (LMWLs) glacier ice/glacier melt (2.5), snow packs/snow (7.7), stream (10.3) reflect mixing ISM. d-excess lie between value a typical (~20‰) (~10‰), moisture from both Atlantic ocean – Mediterranean sea ocean-Bay Bengal-Arabian sea. tracer based hydrographic analysis indicates dominance contributions regional hydrology. Hybrid Single Particle Lagrangian Integrated Trajectory Model (HYSPLIT) model back trajectory mode estimates sources Based on composition associated source regions, QMF oscillates northwest southeast direction depending strength and/or weakness This work hypothesizes for upscale determination description pulsatory extension Himalayas (along BRB).