Decoding Biosphere–Atmosphere Coupling over the Himalayan Ecosystems Using an Entropy-Driven Network Framework

Chamoli district in the Garhwal Himalaya of Uttarakhand serves as an important ecological transition zone linking high-altitude mountain systems to downstream fluvial environments. The region’s rugged topography, rich biodiversity, and glacier-fed river networks significantly contribute to regional hydrological sustainability and climate resilience. However, comprehensive assessments of the mechanisms governing land–atmosphere coupling in this climate-sensitive mountainous terrain remain relatively scarce.

In this study, an information-theoretic framework is applied to investigate seasonal interaction networks between land-surface and atmospheric processes. The analysis considers major hydro meteorological variables, including precipitation (P), air temperature (T), latent heat flux (LH), sensible heat flux (SH), wind speed (WS), incoming shortwave radiation (SWR), and relative humidity (RH). Network structures are evaluated across four climatological seasons: pre-monsoon (March–May), monsoon (June–September), post-monsoon (October–November), and winter (December–February). The constructed interaction networks differentiate between instantaneous linkages representing real-time coupling and lagged connections reflecting memory-dependent influences.

Entropy-based metrics reveal pronounced dynamical variability during the pre-monsoon and monsoon periods, whereas winter conditions exhibit relatively stable and subdued interaction patterns. The post-monsoon season emerges as a transitional phase in the regional land–atmosphere system. SH, SWR, and LHF emerge as the dominant driving variables, exhibiting transfer entropy values of 0.3434, 0.1249, and 0.0455, respectively, whereas T acts as the primary receiving variable with a value of −0.5137. Overall, synchronous coupling intensifies during the monsoon, while winter is characterized by comparatively stronger memory-controlled interactions. A comparative assessment of pre- and post-pandemic periods indicates a reduction in entropy deviations around 2019, followed by a noticeable increase after 2021, suggesting altered information flow within the coupled system. These findings enhance the understanding of seasonal land–atmosphere dynamics over Chamoli and establish a baseline for evaluating future shifts associated with natural climate variability and anthropogenic influences.

Keywords: Land–atmosphere interaction; Information theory; Entropy networks; Biosphere–atmosphere coupling; Himalayan ecosystems.