AAVSO Sudden Ionospheric Disturbance Report February 1991 Observers: A-01 A-03 A-09 A-19 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 YYMMDD Event Peak (UT) Importance 910201 0606 2+ 910201 0723 2 910201 0830 1- 910201 1128 2+ 910201 1230 1 910201 1303 2 910201 1448 2 910201 1621 2+ 910201 1646 1+ 910201 1739 2+ 910201 1916 1 910201 1945 1 910201 2011 2 910202 0708 2 910202 0758 1 910202 0824 1 910202 1009 1+ 910202 1114 3 910202 1317 2 910202 1352 2+ 910202 1553 1 910202 1815 1 910202 1854 2+ 910202 1939 2 910202 2146 2 910202 2210 1- 910202 2224 1 910202 2309 1+ 910202 2340 1+ 910203 0016 1+ 910203 0812 1- 910203 0836 2 910203 0919 2 910203 1024 1- 910203 1057 2+ 910203 1153 1- 910203 1321 1+ 910203 1345 1- 910203 1444 1+ 910203 1508 2 910203 1629 2 910203 1722 1- 910203 1815 1 910203 1828 1- 910203 1851 1+ 910203 1945 1- 910203 2103 1- 910204 0808 1- 910204 0829 2 910204 0944 1 910204 1051 2+ 910204 1346 1+ 910204 1507 1- 910204 1601 1 910204 1611 2 910204 1649 1- 910204 1728 2 910204 1843 2+ 910204 2121 1 910204 2218 1- 910204 2321 1+ 910205 1448 1- 910205 1744 1- 910205 1959 1 910205 2101 2 910205 2220 2+ 910206 0426 2+ 910206 0616 1+ 910206 0649 1 910206 0810 1- 910206 1505 2 910206 1542 1+ 910206 1837 2+ 910206 1912 1- 910206 2020 1 910206 2122 1 910206 2155 2+ 910207 0501 1+ 910207 0800 2+ 910207 0851 1 910207 0935 2 910207 1415 1- 910207 1503 2+ 910207 1631 1 910207 1709 2+ 910207 1845 1- 910207 1943 2+ 910207 2000 1- 910207 2027 1 910207 2120 2 910207 2351 1+ 910208 0015 1- 910208 0250 2+ 910208 0452 1 910208 0515 1+ 910208 0600 2 910208 0655 3+ 910208 0809 1- 910208 1449 2 910208 1530 1 910208 1601 2 910208 1611 1 910210 1402 1- 910210 1410 1- 910210 1533 1- 910210 1737 2 910210 1949 1+ 910210 2059 2 910211 0558 2 910211 0925 2 910211 2121 2 910211 2329 1+ 910212 0756 1- 910212 1554 1- 910212 1800 1 910212 2119 1+ 910213 0414 1 910213 1506 1+ 910213 1642 1 910213 1724 2+ 910213 1901 1- 910213 2149 2+ 910214 0428 1+ 910214 0620 1+ 910214 1233 3+ 910214 2143 2 910215 0534 1+ 910215 0705 2 910215 1300 1- 910215 1739 1 910215 2140 1 910216 0520 3+ 910216 1001 1- 910216 1410 2 910216 1444 1 910216 1551 1 910216 1905 1 910216 2351 1- 910217 0621 2 910217 1232 1 910217 1316 1- 910217 1414 1- 910217 1515 1+ 910217 1656 1+ 910217 1800 1- 910217 1838 2 910217 2030 1 910218 0726 2+ 910218 0923 1 910218 1430 1- 910218 1652 2 910218 1725 3 910218 1759 1 910218 2058 2 910218 2208 1+ 910219 0033 1- 910219 0847 2+ 910219 1006 1- 910219 1018 1- 910219 1051 1- 910219 1230 2+ 910219 1341 1- 910219 1520 1+ 910219 1715 1- 910219 1815 1+ 910219 2211 2 910220 1328 2 910220 1939 1 910220 2051 1 910221 0813 2+ 910221 1010 1- 910221 1053 1- 910221 1245 1+ 910221 1445 1 910221 1555 1+ 910221 1830 1- 910222 0002 1 910222 1422 1- 910222 1729 1- 910222 2017 1+ 910223 1051 2+ 910223 1651 2+ 910223 2307 1+ 910224 0334 2+ 910224 1610 1 910224 1651 1 910224 1839 1+ 910224 2043 1+ 910224 2133 2+ 910225 0801 1- 910225 0815 2+ 910225 1602 2+ 910225 1658 2+ 910225 1715 2+ 910225 1757 2 910225 1836 1 910226 1229 1 910226 1514 1- 910226 1540 1- 910227 1917 1- 910228 0422 1- 910228 1418 1- 910228 1553 1- 910228 1609 1- 910228 1712 1 910228 1825 1- 910228 1831 1+ 910228 2329 2 ******************************************* Importance Summary February 1991 1- events: 56 1 events: 43 1+ events: 34 2 events: 38 2+ events: 32 3 events: 2 3+ events: 3 Total events: 208