Indexing of driving rain exposure in India based on daily gridded data

The severity of rainfall exposure endured by vertical building facades is often quantified using the “annual driving rain index (aDRI)” subjected to the availability of adequate wind and rainfall data. The present endeavor adopts the instance of Indian subcontinent to demonstrate the suitability of gridded data, which represent the average climatic conditions prevailing over approximately square grids, for estimating aDRI over continuous spatial positions including locations for which conventional station data are not available. The wind and rainfall records used pertain to the sixty-year period of 1951-2010. The study compares the quality of aDRI estimates as a function of the temporal resolution of gridded data by evaluating the total, non co-occurring and averaging errors. Regression models have been developed to facilitate a refined estimation of the index for those locations for which only monthly or annual data sets are available. An aDRI map for India at 10 × 10 (lat./long.) resolution has been constituted and the dominant directions of driving rain have been identified based on the analysis of daily gridded data. The discourse concludes with a statistical analysis of yearly driving rain indices to deduce the magnitude and significance of the trends pertinent to individual grids.