<html><head><meta http-equiv="Content-Type" content="text/html charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><br class="">Dear All,<div class=""><br class=""></div><div class="">I tried to calculate SPI based on Pearson 3 option. The SPI values are generated but I see two issues which I am need to be clear about. </div><div class="">1. an error return "<font face="Menlo" class=""><span style="font-size: 11px;" class="">*** ERROR *** ROUTINE CDFPE3 : PARAMETERS INVALID” before returning the SPI values. </span></font></div><div class=""><font face="Menlo" class=""><span style="font-size: 11px;" class="">2. zero precipitation values are considered as missing (for example for 1-month SPI if the precipitation is 0 then the corresponding SPI is indicated as -999.0. Similarly, where three consecutive monthly precipitation was 0 the corresponding 3-month SPI is give as -999.0).</span></font></div><div class=""><font face="Menlo" class=""><span style="font-size: 11px;" class=""><br class=""></span></font></div><div class=""><font face="Menlo" class=""><span style="font-size: 11px;" class="">I kindly ask your comment on these two issues.</span></font></div><div class=""><span style="font-size: 11px; font-family: Menlo;" class=""><br class=""></span></div><div class=""><span style="font-size: 11px; font-family: Menlo;" class="">Thanks</span></div><div class=""><span style="font-size: 11px; font-family: Menlo;" class=""><br class=""></span></div><div class=""><span style="font-size: 11px; font-family: Menlo;" class="">Dawit </span></div></body></html>