Driving rain indices for India at 1°×1° gridded scale

Abstract

Estimates of driving rain index at finer spatial resolutions facilitate a reliable consideration of potential moisture loads in the design of efficient building envelopes for any given location. In this study, a driving rain index map for India has been developed at 1°×1°(lat./long.) resolution using 60-years’ 1951–2010) monthly data for rainfall and wind. The objective has been facilitated by calculating the driving rain indices for each of the 357 grids that cover the entire geographical stretch of India. The results affirm that, large tracts of central, eastern and southern India are shielded from driving rain, while the rest endure moderate to high severity. The higher latitudes of northeastern and west coastal areas are identified as the most severe regions. Furthermore, a non-parametric Mann-Kendall test and Sen's slope estimator have been used to determine the temporal trends of calculated indices at 95% confidence level. The indices have been found to exhibit a statistically significant decreasing trend over several regions of India thereby implying a decline of moisture loads. Estimates of average and most frequent wind directions have also been presented for individual grids to facilitate the design and orientation of building envelopes.