Potomac River 1000 Year May-September Streamflow Reconstruction ----------------------------------------------------------------------- World Data Center for Paleoclimatology, Boulder and NOAA Paleoclimatology Program ----------------------------------------------------------------------- NOTE: Please cite original reference when using these data, plus the data file URL and date accessed. NAME OF DATA SET: Potomac River 1000 Year May-September Streamflow Reconstruction LAST UPDATE: 1/2012 (Original receipt by WDC Paleo) CONTRIBUTORS: Maxwell, R.S., A.E. Hessl, E.R. Cook, and N. Pederson IGBP PAGES/WDCA CONTRIBUTION SERIES NUMBER: 2012-009 WDC PALEO CONTRIBUTION SERIES CITATION: Maxwell, R.S., et al. 2012. Potomac River 1000 Year May-September Streamflow Reconstruction. IGBP PAGES/World Data Center for Paleoclimatology Data Contribution Series # 2012-009. NOAA/NCDC Paleoclimatology Program, Boulder CO, USA. ORIGINAL REFERENCE: Maxwell, R.S., A.E. Hessl, E.R. Cook, and N. Pederson. 2011. A multispecies tree ring reconstruction of Potomac River streamflow (950-2001). Water Resources Research, Vol. 47, W05512, doi:10.1029/2010WR010019. ABSTRACT: Mean May-September Potomac River streamflow was reconstructed from 950-2001 using a network of tree ring chronologies (n = 27) representing multiple species. We chose a nested principal components reconstruction method to maximize use of available chronologies backward in time. Explained variance during the period of calibration ranged from 20% to 53% depending on the number and species of chronologies available in each 25 year time step. The model was verified by two goodness of fit tests, the coefficient of efficiency (CE) and the reduction of error statistic (RE). The RE and CE never fell below zero, suggesting the model had explanatory power over the entire period of reconstruction. Beta weights indicated a loss of explained variance during the 1550-1700 period that we hypothesize was caused by the reduction in total number of predictor chronologies and loss of important predictor species. Thus, the reconstruction is strongest from 1700-2001. Frequency, intensity, and duration of drought and pluvial events were examined to aid water resource managers. We found that the instrumental period did not represent adequately the full range of annual to multidecadal variability present in the reconstruction. Our reconstruction of mean May-September Potomac River streamflow was a significant improvement over the Cook and Jacoby (1983) reconstruction because it expanded the seasonal window, lengthened the record by 780 years, and better replicated the mean and variance of the instrumental record. By capitalizing on variable phenologies and tree growth responses to climate, multispecies reconstructions may provide significantly more information about past hydroclimate, especially in regions with low aridity and high tree species diversity. GEOGRAPHIC REGION: Eastern North America PERIOD OF RECORD: 950-2001 AD FUNDING SOURCES: US NASA WV Space Grant Consortium, West Virginia University Eberly College of Arts and Sciences, US National Science Foundation grant 0925114. DATA FILE URLS: ftp://ftp.ncdc.noaa.gov/pub/data/paleo/treering/reconstructions/northamerica/usa/potomac2011flow.txt ftp://ftp.ncdc.noaa.gov/pub/data/paleo/treering/reconstructions/northamerica/usa/potomac2011flow.xls DESCRIPTION: Reconstruction of May through September Potomac River streamflow for 950-2001 AD at the Point of Rocks, Maryland USGS streamflow gauge. The streamflow reconstruction is based on 27 tree ring chronologies representing multiple species from locations in the Appalachian Mountains and east to the Atlantic Coast in Maryland, Pennsylvania, West Virginia, and Virginia. Some of the tree ring chronologies are available in the International Tree-Ring Data Bank: http://www.ncdc.noaa.gov/paleo/treering.html Point of Rocks, Maryland: 39°16'24.9"N, 77°32'35"W DATA: Maxwell et al. 2011 May-September Potomac River streamflow reconstruction Column 1: Year AD Column 2: Reconstructed May-September Potomac River streamflow (m3/sec) Column 3: Instrumental May-September Mean Potomac River streamflow (m3/sec) Year Recon MJJInst. Mean MJJAS Flow m3/sec 950 201.7 951 138.3 952 174.9 953 178.6 954 224.8 955 147.5 956 88.9 957 207.4 958 180.6 959 100.6 960 188.7 961 122.4 962 71.3 963 151.6 964 113.7 965 196.2 966 170.5 967 78.5 968 177.7 969 183.1 970 141.2 971 212.7 972 181.9 973 149.6 974 147.5 975 203.6 976 121 977 143.5 978 103.5 979 76.2 980 106.9 981 72.7 982 76.7 983 129.4 984 127.9 985 103.5 986 133.9 987 95.9 988 176.1 989 114.2 990 114.2 991 146.1 992 106.9 993 145.8 994 214.2 995 106.9 996 180.2 997 200.3 998 82.8 999 115.6 1000 136.4 1001 89.9 1002 157.7 1003 156.6 1004 101.3 1005 110.6 1006 151.3 1007 210.8 1008 88.1 1009 62.1 1010 248.2 1011 181.9 1012 88.1 1013 206.4 1014 97.2 1015 129.4 1016 181.9 1017 126.1 1018 206 1019 108.6 1020 247.1 1021 320.5 1022 122.7 1023 121.6 1024 100.2 1025 128.5 1026 111.6 1027 144.8 1028 117.2 1029 82.8 1030 132.7 1031 113.2 1032 95.2 1033 81.2 1034 114.5 1035 136.7 1036 128.2 1037 116.1 1038 74.6 1039 117.7 1040 78.1 1041 69.3 1042 127.3 1043 126.4 1044 98.1 1045 104.9 1046 78.5 1047 77.1 1048 121.3 1049 177.3 1050 155.5 1051 146.8 1052 141.5 1053 119.3 1054 134.5 1055 213.2 1056 277.8 1057 246.5 1058 152 1059 108.6 1060 130.6 1061 112.1 1062 138.9 1063 105.4 1064 148.5 1065 140.5 1066 154.8 1067 139.2 1068 127.9 1069 175.3 1070 123.5 1071 119.6 1072 128.8 1073 133.3 1074 151.3 1075 158.4 1076 130 1077 103.7 1078 220.7 1079 128.5 1080 111.6 1081 139.9 1082 118.8 1083 120.2 1084 118.2 1085 167 1086 290.9 1087 325.7 1088 137.7 1089 238.1 1090 216.2 1091 123.8 1092 127.6 1093 136.1 1094 239.2 1095 143.1 1096 120.7 1097 220.7 1098 121.3 1099 153.4 1100 205.5 1101 175.3 1102 192.7 1103 162.8 1104 159.5 1105 193.5 1106 202.7 1107 112.4 1108 119.6 1109 95.7 1110 99 1111 104.4 1112 89.9 1113 169 1114 87.5 1115 123.2 1116 179.4 1117 108.1 1118 194.9 1119 146.8 1120 236.5 1121 295 1122 120.4 1123 131.2 1124 165.9 1125 87.9 1126 130.9 1127 147.2 1128 97 1129 99.3 1130 118.5 1131 190 1132 184.4 1133 103.5 1134 101.8 1135 105.9 1136 206 1137 152.7 1138 130.3 1139 245.9 1140 169 1141 95 1142 117.7 1143 127.3 1144 123 1145 131.5 1146 89.7 1147 103.7 1148 137.7 1149 112.7 1150 127 1151 166.3 1152 88.5 1153 116.6 1154 115.8 1155 101.1 1156 204.5 1157 155.2 1158 84.1 1159 158.4 1160 134.2 1161 81.6 1162 118.8 1163 103 1164 53.8 1165 134.5 1166 98.4 1167 125.3 1168 223.2 1169 85.5 1170 115.6 1171 156.6 1172 133.6 1173 138.9 1174 135.8 1175 110.6 1176 97 1177 108.6 1178 115.6 1179 130.6 1180 79.8 1181 98.4 1182 155.9 1183 77.1 1184 152 1185 165.9 1186 67.3 1187 133.3 1188 275.9 1189 222.7 1190 96.6 1191 173.7 1192 172.1 1193 93.1 1194 130.6 1195 260.5 1196 107.1 1197 97.9 1198 226.9 1199 101.3 1200 108.8 1201 186.5 1202 111.9 1203 169 1204 187.8 1205 171.3 1206 187.8 1207 116.1 1208 94.6 1209 63.6 1210 66.6 1211 109.1 1212 109.1 1213 134.5 1214 68.7 1215 178.2 1216 135.5 1217 101.6 1218 161.7 1219 114.8 1220 112.7 1221 147.8 1222 70.3 1223 171.7 1224 172.5 1225 112.9 1226 125 1227 205.5 1228 206 1229 161 1230 163.2 1231 211.7 1232 156.6 1233 95.5 1234 187 1235 53.4 1236 104.4 1237 157.7 1238 242.5 1239 130.9 1240 162.5 1241 228.4 1242 206.9 1243 179.4 1244 103.9 1245 195.3 1246 125 1247 109.8 1248 216.2 1249 121.8 1250 105.9 1251 123.8 1252 86.7 1253 104.2 1254 87.9 1255 90.7 1256 86.5 1257 115.6 1258 90.7 1259 97.7 1260 137.3 1261 157.7 1262 93.9 1263 139.6 1264 196.2 1265 127.9 1266 141.5 1267 124.7 1268 111.4 1269 114.5 1270 143.8 1271 196.2 1272 101.3 1273 117.2 1274 87.7 1275 132.1 1276 138.9 1277 131.5 1278 161.7 1279 165.9 1280 167.4 1281 242 1282 139.6 1283 118 1284 151.6 1285 190.5 1286 60.8 1287 125.3 1288 232.7 1289 98.6 1290 229.5 1291 150.9 1292 192.2 1293 178.2 1294 143.8 1295 71.1 1296 134.2 1297 288.3 1298 138 1299 169.7 1300 191.3 1301 95.2 1302 146.8 1303 190 1304 214.2 1305 179.8 1306 127 1307 114.8 1308 138.9 1309 84.9 1310 131.5 1311 89.1 1312 132.1 1313 151.6 1314 118.8 1315 179.4 1316 155.5 1317 66.3 1318 86.9 1319 126.4 1320 121.8 1321 115 1322 103.7 1323 82.2 1324 95.9 1325 191.8 1326 128.8 1327 163.6 1328 135.1 1329 165.5 1330 258.1 1331 113.4 1332 113.2 1333 304.6 1334 48.8 1335 79.8 1336 181.9 1337 97.2 1338 252.2 1339 193.1 1340 210.3 1341 160.2 1342 145.5 1343 150.9 1344 178.2 1345 140.5 1346 97.7 1347 131.5 1348 102.3 1349 124.4 1350 90.1 1351 102 1352 209.3 1353 83.5 1354 181 1355 107.8 1356 78.7 1357 182.3 1358 117.7 1359 121.8 1360 192.2 1361 205 1362 290.9 1363 91.8 1364 131.5 1365 176.9 1366 71.7 1367 134.2 1368 122.1 1369 102.3 1370 136.1 1371 68.7 1372 115.6 1373 196.7 1374 138.3 1375 125.5 1376 147.8 1377 149.9 1378 144.1 1379 158.4 1380 187 1381 146.5 1382 110.1 1383 155.2 1384 139.2 1385 129.7 1386 112.9 1387 174.9 1388 78.3 1389 107.1 1390 160.2 1391 72.6 1392 122.1 1393 132.1 1394 118.5 1395 217.2 1396 131.8 1397 90.9 1398 109.6 1399 141.8 1400 57.3 1401 98.1 1402 180.6 1403 123 1404 161.7 1405 136.1 1406 97.9 1407 133.6 1408 87.7 1409 131.5 1410 80.1 1411 99 1412 143.5 1413 134.2 1414 134.5 1415 100 1416 106.1 1417 169.4 1418 90.3 1419 108.1 1420 92.9 1421 131.5 1422 199.9 1423 225.8 1424 128.5 1425 92.2 1426 115.6 1427 97.2 1428 261.1 1429 193.5 1430 72.4 1431 170.9 1432 227.4 1433 154.8 1434 225.8 1435 123 1436 205 1437 213.7 1438 53.3 1439 141.2 1440 182.3 1441 117.4 1442 226.9 1443 192.7 1444 149.9 1445 90.9 1446 138 1447 150.9 1448 146.5 1449 186.1 1450 99.5 1451 90.9 1452 119.3 1453 87.1 1454 124.7 1455 106.6 1456 199.9 1457 137.3 1458 143.8 1459 224.8 1460 134.5 1461 185.3 1462 101.3 1463 104.4 1464 126.4 1465 123.8 1466 107.6 1467 102.5 1468 107.3 1469 136.1 1470 147.5 1471 70.3 1472 70.8 1473 90.9 1474 133.6 1475 167.8 1476 157 1477 229 1478 148.9 1479 176.9 1480 157 1481 141.5 1482 138.6 1483 162.8 1484 151.3 1485 100.4 1486 130.6 1487 228.4 1488 148.5 1489 110.6 1490 88.5 1491 138.9 1492 217.2 1493 216.7 1494 122.4 1495 157.3 1496 91.4 1497 158.8 1498 130.9 1499 166.3 1500 105.6 1501 104.7 1502 118.8 1503 115.8 1504 85.5 1505 95 1506 222.7 1507 176.5 1508 116.9 1509 134.8 1510 190.5 1511 125.8 1512 150.2 1513 131.8 1514 139.6 1515 133.3 1516 197.6 1517 139.9 1518 112.4 1519 134.8 1520 80.5 1521 126.4 1522 150.6 1523 209.3 1524 195.8 1525 102.3 1526 153 1527 149.6 1528 149.6 1529 206 1530 143.1 1531 172.1 1532 138 1533 104.9 1534 95.5 1535 109.1 1536 103.2 1537 142.8 1538 103.2 1539 157.3 1540 169.4 1541 152.7 1542 155.9 1543 176.5 1544 88.9 1545 119.1 1546 96.3 1547 159.1 1548 171.7 1549 134.8 1550 136.7 1551 79.9 1552 116.9 1553 135.8 1554 139.9 1555 94.8 1556 157.3 1557 129.7 1558 103.9 1559 81.1 1560 146.5 1561 163.2 1562 127.6 1563 99.3 1564 167.4 1565 119.1 1566 73.8 1567 151.3 1568 122.4 1569 120.4 1570 99 1571 120.4 1572 125.3 1573 106.9 1574 77.8 1575 78.5 1576 149.2 1577 173.7 1578 136.1 1579 152.7 1580 164 1581 159.1 1582 158.4 1583 273.4 1584 255.1 1585 115 1586 33.8 1587 88.5 1588 117.4 1589 83.9 1590 118 1591 85.7 1592 118 1593 126.1 1594 133.6 1595 101.1 1596 68.4 1597 55.7 1598 52.8 1599 72.7 1600 122.7 1601 151.3 1602 220.7 1603 102.8 1604 244.2 1605 173.3 1606 181.9 1607 88.3 1608 111.1 1609 181.9 1610 98.8 1611 70.3 1612 192.7 1613 270.3 1614 82 1615 194 1616 174.5 1617 146.1 1618 207.4 1619 233.2 1620 72.4 1621 280.4 1622 96.3 1623 79.9 1624 81.2 1625 112.9 1626 65.9 1627 124.4 1628 89.9 1629 109.3 1630 76.2 1631 83.1 1632 92.9 1633 122.1 1634 104.7 1635 100 1636 155.5 1637 107.6 1638 146.8 1639 137.3 1640 101.3 1641 114.8 1642 65.4 1643 171.3 1644 89.5 1645 134.5 1646 129.7 1647 173.3 1648 109.3 1649 182.3 1650 154.1 1651 123.5 1652 247.1 1653 249.3 1654 81.1 1655 212.7 1656 147.8 1657 195.3 1658 234.8 1659 142.8 1660 165.5 1661 248.2 1662 117.4 1663 158.8 1664 154.1 1665 124.1 1666 233.2 1667 124.1 1668 192.2 1669 136.4 1670 89.3 1671 133.6 1672 394.3 1673 98.4 1674 139.6 1675 139.2 1676 151.3 1677 191.8 1678 97.7 1679 158 1680 78.7 1681 132.1 1682 181.5 1683 127.9 1684 118.8 1685 161.4 1686 66.5 1687 98.4 1688 148.2 1689 159.1 1690 140.9 1691 101.6 1692 116.4 1693 132.7 1694 142.5 1695 205.5 1696 100.6 1697 60.6 1698 91.2 1699 77.6 1700 90.1 1701 134.8 1702 77.2 1703 76 1704 80.3 1705 124.4 1706 150.6 1707 83.7 1708 110.9 1709 124.7 1710 155.2 1711 107.8 1712 109.8 1713 87.5 1714 88.7 1715 112.7 1716 229 1717 139.2 1718 111.1 1719 145.8 1720 126.7 1721 160.6 1722 106.9 1723 150.2 1724 221.7 1725 84.9 1726 120.2 1727 116.4 1728 189.6 1729 159.5 1730 160.6 1731 103.9 1732 90.7 1733 99.5 1734 87.5 1735 264.7 1736 164.4 1737 122.7 1738 190 1739 245.9 1740 108.1 1741 147.5 1742 142.2 1743 108.1 1744 165.9 1745 97.5 1746 139.6 1747 52.7 1748 135.5 1749 200.8 1750 248.2 1751 166.3 1752 179.8 1753 316.8 1754 109.3 1755 141.2 1756 175.3 1757 150.2 1758 169.4 1759 101.6 1760 174.9 1761 132.1 1762 175.3 1763 112.9 1764 101.3 1765 104.9 1766 110.9 1767 118.2 1768 212.2 1769 126.1 1770 169.4 1771 106.6 1772 127.9 1773 89.5 1774 43.7 1775 167.8 1776 119.9 1777 84.3 1778 89.7 1779 59.5 1780 182.7 1781 103 1782 131.5 1783 87.5 1784 109.3 1785 138.9 1786 135.1 1787 106.4 1788 111.9 1789 104.4 1790 75.3 1791 66.5 1792 182.3 1793 189.1 1794 145.5 1795 272.1 1796 93.9 1797 92 1798 131.2 1799 144.1 1800 136.7 1801 141.8 1802 100 1803 98.6 1804 167 1805 85.9 1806 87.3 1807 162.5 1808 133.3 1809 120.2 1810 98.4 1811 110.4 1812 87.5 1813 123.5 1814 184 1815 110.6 1816 154.4 1817 125.3 1818 91.4 1819 82.9 1820 90.1 1821 97.9 1822 99 1823 167 1824 185.3 1825 131.2 1826 207.9 1827 190 1828 136.7 1829 150.6 1830 173.3 1831 144.5 1832 201.3 1833 188.3 1834 111.4 1835 147.5 1836 129.7 1837 110.6 1838 59.3 1839 152.7 1840 161 1841 117.2 1842 118.8 1843 80.1 1844 96.3 1845 114.8 1846 119.9 1847 104.4 1848 114.2 1849 111.6 1850 102.3 1851 114.2 1852 99 1853 176.5 1854 120.4 1855 126.4 1856 127 1857 177.7 1858 105.4 1859 123.8 1860 86.9 1861 107.1 1862 157 1863 86.3 1864 98.4 1865 99 1866 123.5 1867 117.7 1868 105.1 1869 133 1870 153 1871 73.8 1872 107.1 1873 97.5 1874 124.7 1875 140.5 1876 135.8 1877 165.1 1878 154.8 1879 71.4 1880 113.2 1881 109.8 1882 121.8 1883 182.3 1884 131.2 1885 102.3 1886 124.7 1887 96.3 1888 166.3 1889 192.7 1890 105.1 1891 145.1 1892 123.2 1893 97.5 1894 91.4 1895 77.1 104.4 1896 163.6 120.9 1897 110.4 166.2 1898 114.2 178.8 1899 97.9 109.1 1900 85.1 88 1901 161.4 364.1 1902 155.2 82.9 1903 207.4 225.5 1904 124.1 124.3 1905 147.8 161.1 1906 184.4 182.2 1907 143.1 231.9 1908 141.2 179 1909 172.1 111.9 1910 67.1 138.3 1911 87.3 114 1912 153.4 204.3 1913 81.1 143.9 1914 97.9 82.1 1915 212.7 184 1916 236.5 164.8 1917 91.8 102.4 1918 112.1 106.7 1919 136.4 155.8 1920 115.8 178.6 1921 130 156.8 1922 145.1 113.6 1923 128.2 83.9 1924 145.5 242.3 1925 75.5 72.7 1926 116.9 135.5 1927 230 129.7 1928 165.9 293.3 1929 83.3 110.6 1930 82 39.3 1931 140.2 143 1932 96.1 85.6 1933 121.3 218.4 1934 186.5 91.1 1935 168.6 165.6 1936 86.5 84.7 1937 250.5 189.9 1938 260.5 131.8 1939 108.3 131.2 1940 160.2 218 1941 103.5 105.6 1942 175.7 193.2 1943 107.3 114.3 1944 94.1 93.2 1945 164.7 194.5 1946 101.6 139.9 1947 115 124.9 1948 177.3 155.4 1949 334 257.8 1950 260.5 163.2 1951 103.5 142.4 1952 161 164.4 1953 179.4 110.2 1954 117.4 90.7 1955 150.6 198.4 1956 146.1 134.4 1957 120.2 70.7 1958 128.2 170.1 1959 79.4 91.7 1960 181 161.8 1961 118.8 115.9 1962 109.6 86.9 1963 45.6 68.3 1964 94.1 72.4 1965 70.8 57.8 1966 80.1 73.1 1967 120.4 149.9 1968 91.2 107.5 1969 119.1 99.5 1970 108.1 130.3 1971 168.2 191.1 1972 214.7 319.9 1973 126.1 197.3 1974 175.3 142.8 1975 222.2 268 1976 67 90 1977 101.1 55.6 1978 211.2 226.6 1979 150.2 245.6 1980 106.9 142.6 1981 83.3 126.9 1982 159.9 148.6 1983 64.7 127.7 1984 103.5 188.5 1985 120.4 114.7 1986 61.9 75.3 1987 72.4 132.4 1988 120.4 123.1 1989 179.4 282.2 1990 239.2 147.1 1991 102.3 74.3 1992 205.5 166.6 1993 199 106.6 1994 189.6 152.2 1995 177.3 155.4 1996 80.5 504.8 1997 192.7 105.9 1998 97.7 140.7 1999 185.3 66.2 2000 236.5 158.8 2001 102.3 123.9