diff -up ncl_ncarg-6.1.2/ni/src/lib/nfp/datesW.c.calendar ncl_ncarg-6.1.2/ni/src/lib/nfp/datesW.c
--- ncl_ncarg-6.1.2/ni/src/lib/nfp/datesW.c.calendar	2013-02-06 22:28:32.000000000 -0500
+++ ncl_ncarg-6.1.2/ni/src/lib/nfp/datesW.c	2014-01-27 22:50:59.427972326 -0500
@@ -688,6 +688,7 @@ int day_of_year (int year, int month, in
   }
   if(!strcasecmp(calendar,"standard")  || 
      !strcasecmp(calendar,"gregorian") ||
+     !strcasecmp(calendar,"proleptic_gregorian") ||
      !strcasecmp(calendar,"julian") ||
      !strcasecmp(calendar,"none")) {
     if (  (isleapyear(year,calendar) && month == 2 && day > 29) ||
@@ -757,6 +758,7 @@ int days_in_month (int year, int month, 
   }
   if(!strcasecmp(calendar,"standard")  || 
      !strcasecmp(calendar,"gregorian") ||
+     !strcasecmp(calendar,"proleptic_gregorian") ||
      !strcasecmp(calendar,"julian") ||
      !strcasecmp(calendar,"none")) {
     dinm = daysinmonth[month-1];
@@ -855,6 +857,7 @@ int monthday (int year, int dayofyear, c
 
   if(!strcasecmp(calendar,"standard")  || 
      !strcasecmp(calendar,"gregorian") ||
+     !strcasecmp(calendar,"proleptic_gregorian") ||
      !strcasecmp(calendar,"julian") ||
      !strcasecmp(calendar,"none")) {
 /* 
@@ -960,6 +963,7 @@ int seconds_in_year (int year, const cha
   nsid = 86400;      /* num seconds in a day */
   if(!strcasecmp(calendar,"standard")  || 
           !strcasecmp(calendar,"gregorian") ||
+          !strcasecmp(calendar,"proleptic_gregorian") ||
           !strcasecmp(calendar,"julian") ||
           !strcasecmp(calendar,"none")) {
     tsiy = isleapyear(year,calendar) ? 366*nsid : 365*nsid;
@@ -1014,6 +1018,7 @@ int isleapyear(int year,const char *cale
 
   if(!strcasecmp(calendar,"standard")  || 
      !strcasecmp(calendar,"gregorian") ||
+     !strcasecmp(calendar,"proleptic_gregorian") ||
      !strcasecmp(calendar,"none")) {
     y4   = (year % 4) == 0;
     y100 = (year % 100) == 0;