Monsoon meteorology and agricultural phenology structure atmospheric transport of aerial biomass across the Indian subcontinent

Mansi Mungee 

The movement of organisms through the atmosphere is a fundamental but under-observed
ecological process that redistributes biomass, genes, and ecological interactions across continents.
Aeroecology has revealed that such movements are strongly determined by synoptic and mesoscale
atmospheric dynamics, which jointly determine when, where, and at what altitudes animals initiate,
sustain, and terminate flight. However, current understanding is derived largely from temperate
climatologies, leaving tropical aeroecology, where atmospheric circulation regimes are
fundamentally different, poorly resolved. Here, I synthesize existing literature on radar observations,
migration studies, and atmospheric dynamics to examine how monsoon-dominated tropical
atmosphere structures aerial movement across the Indian subcontinent at inter-continental (>1000
km) and intra-peninsular (100 – 500 km) scales.
Across trophic levels, long-distance migratory movements are jointly organized by synoptic-scale
monsoon flow and its seasonal reversal, orographic channeling and uplift along the Himalayan
barrier, and spatial constriction at coastal bottlenecks along the western coast of the peninsula. These
processes generate a common set of migration corridors for both, birds and insects, including trans-
Himalayan, circum-Himalayan, Indo-African, and Indo-East/Southeast Asian pathways. At regional
scales, evidence from the limited but critical radar observations indicates that aerial dispersal is
tightly coupled to intraseasonal active–break phases of the monsoon, the stability and intermittency
of diel boundary-layer transitions (including the strength of nocturnal low-level jets), and –
particularly for insect pests – cropping cycles and agricultural phenology.
Despite these distinctive dynamics, radar aeroecology in the tropics remains sparse. India’s rapidly
expanding weather-radar network, especially its dual-polarization X- and C-Band coverage across the
western coast and the western Himalayan arc, provides an exceptional but underutilized platform for
strengthening tropical aeroecology. By explicitly integrating monsoon meteorology, ecology, and
radar aeroecology, this synthesis provides a framework for advancing a mechanistic, globally
representative understanding of tropical aeroecology.