Seasonal Changes in Precipitable Water and Its Influence on Total Precipitation: Linkages with Climate Modes over the the Northeastern Region of India

Abstract Atmospheric moisture governs seasonal variability, but its strength and its linkage with rainfall over the complex topography of northeastern India remain unexplored. Precipitable Water (PW), representing the total column atmospheric moisture, is expected to increase with global warming. Using ERA5 reanalysis data (1990–2024), this study examines the climatology, vertical structure and coupling of PW and Total Precipitation (TP) over the Northeastern Region of India (NRI). It also analyzes Vertically Integrated Moisture Transport (VIMT) and links with climate modes. Seasonal variability in PW is pronounced, with minimum values during winter (10–20 mm) and peak values during the monsoon (55–70 mm). Trend analysis shows PW significantly increase during monsoon (~ 0.08 mm yr − ¹), with insignificant trends in other seasons. Monsoon PW reaches ~ 64–71 mm over the NRI, whereas TP shows strong interannual variability (~ 11–22 mm day − ¹). Pre-monsoon PW and TP correlations are highest but weaken or become negative during the monsoon over parts of Assam. Seasonal PW-TP coupling is modulated by the El Niño–Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD), with stronger large-scale control during the monsoon and post-monsoon seasons. These findings provide insights for regional hydrological assessment and support climate adaptation over the NRI.