3.1.1. Shortlisting Based on Changes in the Means

As a first step, the total number of available model runs (ensemble member *r1p1i1*) for RCP4.5 (42) and RCP8.5, (39) were evaluated and shortlisted based on the change presented by them, in terms of the mean annual precipitation sum (Δ*P)* and the mean air temperature (Δ*T)*, averaged across the UIB, between the simulated reference period historical data (1976–2005) and the late 21st-century projected data (2071–2100). The calculations were done using the web-based application "Climate Explorer" managed by the Royal Netherlands Meteorological Institute (KNMI) (http://climexp.knmi.nl).

As our intention was to identify fewer model runs that best represent the four corners of the full spectrum, as well as the central and middle tendencies, we first determined the 10th, 50th and 90th percentile values of Δ*P* and Δ*T* for the entire ensemble considered for each RCP, to explore the extent of the full spectrum of the projected changes in temperature and precipitation under that RCP. This was followed by determining the four (4) closest projections to each of the corners, as well as the center of the spectrum. The total number of shortlisted model runs for each of the two RCPs then amounted to 20.

Details of the different parts of the full spectrum considered during this study are as follows:


The identification of the closest model runs to any corner point was done according to the procedure suggested by [19]. It should be noted that 10th and 90th percentiles were selected as the central points of the corners, rather than the maximum or minimum values, in order to avoid selection of any outlier projections.
