Fig. 3

Evaluation of moisture budget diagnostics in ERA5moistIN against ERA5 reference quantities (RMSE in kg m⁻² hr⁻¹). Root Mean Square Error (RMSE) maps (in kg m⁻² hr⁻¹, equivalent to mm hr⁻¹) are shown for four seasons—MAM (March–May), JJAS (June–September), ON (October–November), and DJF (December–February) over the period 1940–2024, comparing ERA5’s native vertically integrated moisture convergence (VIMC) with (A) horizontal moisture flux convergence (HMFC) from ERA5moistIN; (B) vertical moisture flux convergence (VMFC); (C) sum of HMFC and VMFC (i.e., reconstructed total moisture convergence from ERA5moistIN); and (D) ERA5’s time derivative of total column water vapor (\(\frac{d({TCWV})}{{dt}}\)) with the change in storage term from ERA5moistIN. All quantities are vertically integrated from the surface to the top of the atmosphere. Notably, ERA5moistIN’s vertical integration extends only up to 300 hPa, whereas native ERA5 products (VIMC and TCWV) are integrated up to 0.01 hPa. Despite this difference, RMSE values remain low, particularly in panels (C,D) indicating that ERA5moistIN diagnostics effectively capture the dominant components of moisture transport and storage within the troposphere.