AAVSO Sudden Ionospheric Disturbance Report December 1991 Observers: A-03 A-09 A-40 A-50 A-52 A-59 A-61 A-62 A-63 A-64 A-65 A-66 A-67 A-68 A-69 A-70 A-71 A-72 A-73 A-74 YYMMDD Event Peak (UT) Importance 911201 0434 1+ 911201 1904 1+ 911202 0935 2 911202 1143 1- 911202 1217 2 911202 1304 1 911202 1411 1+ 911202 1503 2 911202 1749 1 911202 1846 2+ 911202 1932 2 911202 2008 1- 911202 2313 1- 911202 2340 1+ 911203 1637 2+ 911204 1436 2 911204 1750 2+ 911205 0130 1- 911205 0235 1+ 911205 0734 2 911205 1100 2 911205 1155 2 911205 1306 2 911205 1407 1- 911205 1619 1- 911205 1717 1- 911205 1951 1- 911205 2013 1+ 911206 0449 1+ 911206 1148 1- 911206 1225 1 911206 1559 2+ 911206 2006 1- 911206 2015 2 911206 2043 2 911206 2105 1+ 911207 0018 1 911207 1235 2+ 911207 1515 1+ 911207 1545 1- 911207 1601 1 911207 1801 1 911207 1823 1 911207 1900 1 911207 1931 1- 911207 1959 1- 911207 2107 1 911207 2122 1- 911207 2154 2 911207 2250 1+ 911208 0015 1- 911208 0619 2 911208 0802 1- 911208 1440 1- 911208 1457 1 911208 1602 2+ 911208 1703 2+ 911208 1808 1 911208 1913 1+ 911208 2001 1- 911208 2051 2 911208 2308 1- 911208 2317 1+ 911209 0648 1- 911209 0739 1 911209 0823 1+ 911209 0944 2+ 911209 1212 1 911209 1246 1 911209 1316 1+ 911209 1347 2 911209 1429 1 911209 1534 1 911209 1707 1 911209 1731 1- 911209 1751 1+ 911209 1809 1 911209 1854 1- 911209 1914 1 911209 2001 1+ 911209 2155 2+ 911210 0107 1+ 911210 0403 1+ 911210 0750 1+ 911210 0814 1- 911210 0855 1 911210 0908 1 911210 1100 1 911210 1122 1 911210 1154 1- 911210 1252 1 911210 1428 1- 911210 1552 1- 911210 1634 1+ 911210 1815 1+ 911210 1843 1- 911210 1952 1 911210 2112 1 911211 0810 2 911211 0937 2 911211 1129 1+ 911211 1233 2 911211 1506 2+ 911211 1832 1- 911211 1915 1- 911211 2103 1+ 911212 0115 1+ 911212 1637 1+ 911212 1709 1+ 911212 1733 1- 911213 0350 2+ 911213 1259 1 911213 1429 1 911213 1630 2+ 911213 1754 1 911214 0102 2 911214 0725 3+ 911214 1450 1 911214 1703 2+ 911214 1905 1- 911214 1924 1- 911214 2056 1 911215 0001 1 911215 0246 1 911215 0530 1 911215 0556 1+ 911215 0630 2+ 911215 1027 2 911215 1246 2 911215 1358 1 911215 1422 1- 911215 1430 1- 911215 1530 1 911215 1800 1 911215 1832 2 911215 1921 1- 911215 1940 1- 911215 2000 1 911215 2120 1- 911216 1204 1 911216 1312 1- 911216 1515 2 911216 1924 1- 911216 1945 2+ 911216 2207 1- 911217 0625 2+ 911217 1520 2 911217 1721 2 911217 1940 2 911218 1027 2+ 911218 1221 1 911218 1334 1+ 911218 1654 2 911218 2207 1 911219 1308 1- 911219 1908 1- 911219 1950 1 911220 1405 3 911220 1901 1+ 911221 0420 2+ 911221 0814 1 911221 1057 2 911221 1154 1- 911221 1204 1+ 911221 1327 1+ 911221 1506 2 911221 1613 1 911221 1807 1- 911221 1820 2+ 911221 2100 2 911222 0530 2+ 911222 0800 2 911222 0915 2+ 911222 1103 1+ 911222 1249 1 911222 1353 1- 911222 1417 1 911222 1656 3 911222 1741 1 911222 2043 2 911223 0747 3+ 911223 1244 2 911223 1705 1- 911223 1742 1 911223 2138 2 911224 0309 1+ 911224 1021 2 911224 1539 1 911224 1612 2+ 911224 1836 1 911224 2018 1- 911224 2255 1 911225 1014 2 911225 1101 2 911225 1301 2 911225 1425 1- 911225 1442 1+ 911225 1500 2+ 911226 0428 1 911226 0454 1 911226 0620 1- 911226 0635 2+ 911226 0732 2 911226 0840 1 911226 0942 2+ 911226 1048 1 911226 1210 1- 911226 1230 1- 911226 1335 1 911226 1433 1 911226 1500 1- 911226 1609 1- 911226 1719 2 911226 1833 1- 911226 2035 1- 911226 2045 1+ 911226 2142 1+ 911227 0310 1+ 911227 0615 2 911227 0914 1 911227 1110 1 911227 1633 1 911227 1720 3 911228 0909 1- 911228 0952 2+ 911228 1040 1- 911228 1054 1 911228 1229 1+ 911228 1545 2 911228 1613 2 911228 1809 1 911228 1825 1 911228 1957 2+ 911228 2111 2 911229 1203 2+ 911229 1329 1+ 911229 1536 1- 911229 1600 1+ 911229 1918 2 911229 2053 1+ 911229 2126 1 911230 1017 1+ 911230 1230 1- 911230 1238 2 911230 1447 1 911230 1516 1- 911230 1551 1+ 911230 1620 1+ 911230 1851 1+ 911230 1936 2+ 911230 2100 1- 911230 2123 1- 911230 2308 2+ 911231 0035 2 911231 1027 2 911231 1445 1 911231 1545 2+ 911231 2248 1- 911231 2354 1 ******************************************* Importance Summary December 1991 1- events: 63 1 events: 67 1+ events: 45 2 events: 48 2+ events: 31 3 events: 3 3+ events: 2 Total events: 259