Determine the fraction of the northern rainfall excess attributable to under-observation

Determine how much of the apparent northern over-prediction in the 9 km WRF simulations of the July 2023 Western Himalayan rainfall event is attributable to under-observation in the sparse high-elevation IMD gauge network rather than to model error, using an independent satellite-based reference such as IMERG.

Background

All seven displayed WRF configurations produce a coherent northern rainfall excess, while IMERG, ERA5, and GFS also indicate substantial rainfall in that region. Because the IMD gridded product is based on a sparse high-elevation gauge network, the apparent model over-prediction may partly reflect under-observation. The paper does not partition these sources of discrepancy and identifies verification against an independent satellite reference as the appropriate way to constrain the unresolved attribution.

References

The region lies at high elevation where the IMD gauge network is sparse, so an unknown fraction of the apparent over-prediction may reflect under-observation rather than model error.

— Cumulus parameterization controls simulated rainfall more than microphysics, but not at heavy thresholds: a 3 * 2 factorial WRF study over the Western Himalaya  (2610.17896 - Kumar et al., 13 Oct 2026) in Section 3.6, Fig. 5 discussion; Section 4.4, Observational reference