Northern Hemisphere Annual Temperature Reconstruction ----------------------------------------------------------------------- World Data Center for Paleoclimatology, Boulder and NOAA Paleoclimatology Program ----------------------------------------------------------------------- NOTE: PLEASE CITE ORIGINAL REFERENCE WHEN USING THIS DATA!!!!! NAME OF DATA SET: Northern Hemisphere Annual Temperature Reconstruction LAST UPDATE: 2/2009 (Original receipt by WDC Paleo) CONTRIBUTOR: Eugene R. Wahl, NOAA NCDC Paleoclimatology IGBP PAGES/WDCA CONTRIBUTION SERIES NUMBER: 2009-008 WDC PALEO CONTRIBUTION SERIES CITATION: Ammann, C.M. and E.R. Wahl. 2009. Northern Hemisphere Annual Temperature Reconstruction. IGBP PAGES/World Data Center for Paleoclimatology Data Contribution Series # 2009-008. NOAA/NCDC Paleoclimatology Program, Boulder CO, USA. ORIGINAL REFERENCE: Ammann, C.M. and E.R. Wahl. 2007. The importance of the geophysical context in statistical evaluations of climate reconstruction procedures Climatic Change, Vol. 85, pp. 71-88. doi: 10.1007/s10584-007-9276-x ABSTRACT: A portion of the debate about climate reconstructions of the past millennium, and in particular about the well-known Mann-Bradley-Hughes ("MBH" 1998, 1999) reconstructions, has become disconnected from the goal of understanding natural climate variability. Here, we reflect on what can be learned from recent scientific exchanges and identify important challenges that remain to be addressed openly and productively by the community. One challenge arises from the real, underlying trend in temperatures during the instrumental period. This trend can affect regression-based reconstruction performance in cases where the calibration period does not appropriately cover the range of conditions encountered during the reconstruction. However, because it is tied to a unique spatial pattern driven by change in radiative balance, the trend cannot simply be removed in the method of climate field reconstruction used by MBH on the statistical argument of preserving degrees of freedom. More appropriately, the influence from the trend can be taken into account in some methods of significance testing. We illustrate these considerations as they apply to the MBH reconstruction and show that it remains robust back to AD 1450, and given other empirical information also back to AD 1000. However, there is now a need to move beyond hemispheric average temperatures and to focus instead on resolving climate variability at the socially more relevant regional scale. ADDITIONAL REFERENCE: Wahl, E.R. and C.M. Ammann. 2007. Robustness of the Mann, Bradley, Hughes reconstruction of Northern Hemisphere surface temperatures: Examination of criticisms based on the nature and processing of proxy climate evidence. Climatic Change, Vol. 85, pp. 33-69. doi: 10.1007/s10584-006-9105-7 SUPPLEMENTAL MATERIAL: http://www.cgd.ucar.edu/ccr/ammann/millennium/MBH-reevaluation.html GEOGRAPHIC REGION: Northern Hemisphere PERIOD OF RECORD: 1000 - 1980 AD FUNDING SOURCES: Weather and Climate Impacts Assessment Science Program at the National Center for Atmospheric Research. DESCRIPTION: Northern hemisphere multiproxy average annual temperature reconstruction for the past millennium. The reconstruction uses multiple proxy types, input into inverse regression-truncated EOF climate field reconstruction spanning entire globe at incomplete 5x5 deg grid. Only N. Hemisphere average is reported here. This reconstruction is based on the Wahl-Ammann emulation of the Mann, Bradley, Hughes (1998/9) reconstruction algorithm and MBH original data. It contains corrections for the centering convention used in N. American tree-ring principal component summaries (centered over full length), as well as elimination of the Gaspe (Canada) tree ring proxy series during 1400-1449. Temperatures are reported in degrees C anomalies from AD 1902-1980 mean. DATA: Column 1: Year AD Column 2: Annual Temperature, deg C, anomalies from AD 1902-1980 mean Year Tanom 1000 0.1204 1001 -0.11331 1002 -0.062493 1003 -0.14835 1004 -0.005979 1005 -0.067487 1006 0.0093026 1007 0.059683 1008 -0.090614 1009 0.040362 1010 0.16992 1011 -0.07681 1012 -0.12809 1013 -0.0283 1014 -0.049972 1015 -0.10344 1016 -0.088377 1017 -0.068441 1018 -0.21484 1019 -0.012908 1020 0.15496 1021 0.065333 1022 -0.060428 1023 0.019115 1024 0.023964 1025 -0.011886 1026 -0.08667 1027 0.059611 1028 -0.07629 1029 -0.034837 1030 -0.065282 1031 -0.14368 1032 -0.011736 1033 -0.10768 1034 -0.11906 1035 -0.068571 1036 0.064727 1037 0.19509 1038 -0.017365 1039 -0.034449 1040 -0.020425 1041 -0.015404 1042 0.0017224 1043 0.037059 1044 0.13042 1045 0.1695 1046 0.072954 1047 -0.09995 1048 0.064231 1049 -0.011455 1050 -0.026075 1051 0.18508 1052 0.074772 1053 -0.025521 1054 -0.14654 1055 -0.10996 1056 -0.045271 1057 0.074047 1058 0.050733 1059 -0.20064 1060 -0.074545 1061 0.0441 1062 0.038989 1063 -0.17705 1064 0.07927 1065 -0.078497 1066 0.092037 1067 0.025093 1068 -0.19115 1069 -0.061943 1070 0.020509 1071 -0.004548 1072 0.11525 1073 -0.006855 1074 -0.046274 1075 0.03372 1076 -0.038712 1077 -0.15448 1078 -0.30614 1079 0.15545 1080 0.16033 1081 0.048549 1082 -0.10588 1083 -0.074388 1084 0.11497 1085 0.04139 1086 0.24028 1087 -0.035247 1088 -0.007062 1089 -0.15614 1090 0.11213 1091 0.15623 1092 0.19257 1093 -0.076318 1094 -0.10141 1095 0.0048848 1096 0.012339 1097 -0.016922 1098 -0.093875 1099 0.064716 1100 0.0063913 1101 0.18282 1102 0.02762 1103 0.082899 1104 0.044221 1105 0.0089131 1106 0.11775 1107 0.16689 1108 0.098611 1109 -0.05309 1110 -0.1882 1111 0.089254 1112 0.071923 1113 -0.036576 1114 -0.13875 1115 -0.114 1116 -0.038082 1117 0.019884 1118 -0.066306 1119 -0.081215 1120 -0.20413 1121 -0.19246 1122 0.031565 1123 -0.11091 1124 -0.029764 1125 0.10047 1126 -0.018294 1127 -0.19026 1128 -0.07337 1129 -0.019497 1130 -0.19734 1131 -0.065973 1132 -0.079249 1133 -0.046028 1134 0.044443 1135 -0.034255 1136 -0.081564 1137 -0.05286 1138 -0.037994 1139 -0.15758 1140 -0.10259 1141 -0.0819 1142 -0.24456 1143 0.04154 1144 -0.17571 1145 -0.13077 1146 -0.10371 1147 -0.030346 1148 0.070213 1149 -0.050545 1150 -0.11242 1151 -0.056515 1152 0.1164 1153 0.12361 1154 0.08548 1155 -0.036929 1156 -0.061771 1157 0.0067241 1158 0.028741 1159 -0.12523 1160 0.042396 1161 0.15965 1162 -0.064842 1163 0.040849 1164 0.11408 1165 0.019046 1166 0.096313 1167 0.080974 1168 0.16635 1169 0.078835 1170 0.21246 1171 0.20713 1172 0.18678 1173 0.085015 1174 0.13889 1175 0.097284 1176 0.019598 1177 -0.065036 1178 -0.054713 1179 -0.089361 1180 0.24743 1181 0.12599 1182 -0.048608 1183 0.028784 1184 0.11579 1185 -0.10807 1186 -0.047462 1187 0.026722 1188 0.047753 1189 -0.022223 1190 0.2318 1191 -0.13608 1192 -0.16509 1193 0.225 1194 -0.26466 1195 -0.12409 1196 -0.24163 1197 -0.16078 1198 -0.063161 1199 -0.1318 1200 -0.16602 1201 -0.25768 1202 -0.032356 1203 0.031857 1204 -0.1384 1205 -0.12798 1206 -0.18691 1207 -0.14668 1208 -0.27096 1209 -0.077675 1210 -0.18617 1211 0.03024 1212 0.0092658 1213 -0.15423 1214 -0.11468 1215 0.026736 1216 -0.011698 1217 -0.19733 1218 -0.063504 1219 -0.22073 1220 0.0084773 1221 0.17323 1222 0.13766 1223 -0.008028 1224 0.24516 1225 0.11252 1226 -0.16068 1227 -0.1419 1228 -0.1426 1229 -0.21191 1230 -0.11825 1231 0.058656 1232 -0.038663 1233 -0.035723 1234 -0.15454 1235 0.015395 1236 -0.043614 1237 -0.070206 1238 0.012845 1239 -0.12666 1240 0.0004876 1241 -0.16115 1242 -0.14923 1243 -0.098834 1244 -0.19654 1245 -0.072476 1246 -0.13363 1247 -0.20689 1248 0.16883 1249 0.31377 1250 0.085086 1251 -0.14728 1252 0.1247 1253 0.23988 1254 0.10907 1255 0.073843 1256 -0.092194 1257 -0.1273 1258 -0.049538 1259 0.038083 1260 -0.10474 1261 -0.17976 1262 -0.20281 1263 -0.21942 1264 -0.046408 1265 -0.054725 1266 -0.050977 1267 -0.097539 1268 -0.10405 1269 -0.031253 1270 -0.054449 1271 0.023498 1272 0.0050202 1273 0.013824 1274 -0.029536 1275 0.0098371 1276 -0.076657 1277 -0.12981 1278 -0.12937 1279 -0.047039 1280 0.080428 1281 -0.04784 1282 0.039198 1283 0.17386 1284 -0.06023 1285 -0.056512 1286 0.055307 1287 -0.0224 1288 -0.15833 1289 -0.053731 1290 -0.054346 1291 0.026452 1292 -0.031607 1293 -0.13777 1294 -0.003256 1295 0.04152 1296 -0.13375 1297 -0.21402 1298 -0.000931 1299 -0.063719 1300 0.03656 1301 -0.002417 1302 -0.13762 1303 -0.067448 1304 0.0066583 1305 -0.016685 1306 0.11782 1307 0.058311 1308 0.040322 1309 -0.20745 1310 -0.093317 1311 0.1825 1312 0.010254 1313 -0.10517 1314 0.17214 1315 0.088377 1316 0.11907 1317 9.70E-05 1318 0.10142 1319 0.0031414 1320 -0.058582 1321 0.10884 1322 -0.055048 1323 -0.05405 1324 0.016045 1325 0.13558 1326 0.059669 1327 -0.018693 1328 -0.040266 1329 -0.11507 1330 -0.17733 1331 0.17542 1332 -0.13627 1333 -0.16663 1334 -0.16889 1335 -0.16183 1336 -0.15548 1337 -0.15036 1338 -0.11373 1339 -0.18691 1340 -0.30784 1341 -0.23289 1342 -0.1927 1343 -0.13151 1344 -0.11229 1345 -0.29638 1346 -0.24053 1347 -0.24416 1348 -0.3149 1349 -0.29516 1350 -0.2499 1351 -0.19565 1352 -0.22361 1353 -0.041965 1354 -0.003978 1355 -0.045675 1356 -0.038162 1357 -0.077017 1358 -0.1122 1359 -0.044187 1360 -0.12236 1361 -0.11117 1362 0.015655 1363 -0.1316 1364 -0.045009 1365 0.0093951 1366 0.3 1367 -0.091424 1368 0.1878 1369 -0.058961 1370 -0.000652 1371 0.13202 1372 0.16146 1373 0.0018803 1374 0.1128 1375 -0.040693 1376 -0.071879 1377 -0.1286 1378 -0.006223 1379 -0.017874 1380 -0.052712 1381 0.095508 1382 0.054057 1383 0.04925 1384 -0.12927 1385 -0.04685 1386 -0.048723 1387 0.007978 1388 0.16375 1389 0.088447 1390 0.046368 1391 0.11996 1392 0.0069922 1393 0.046376 1394 -0.045201 1395 0.056659 1396 0.11489 1397 0.050622 1398 0.048304 1399 -0.10491 1400 0.0023848 1401 -0.1628 1402 0.26082 1403 0.11544 1404 0.067682 1405 0.11416 1406 0.21999 1407 0.044643 1408 -0.029936 1409 0.079013 1410 -0.05518 1411 0.01508 1412 -0.15479 1413 -0.035013 1414 -0.1734 1415 0.16744 1416 0.081215 1417 -0.086581 1418 -0.096898 1419 -0.005958 1420 -0.028243 1421 -0.1438 1422 0.030825 1423 0.013058 1424 0.12367 1425 0.061145 1426 0.17189 1427 -0.011551 1428 -0.000954 1429 -0.010977 1430 0.10791 1431 0.012485 1432 0.035554 1433 0.053156 1434 0.14347 1435 0.091521 1436 0.0076337 1437 0.047134 1438 0.050727 1439 -0.1672 1440 0.075464 1441 0.086569 1442 -0.1238 1443 0.047605 1444 -0.028237 1445 -0.10765 1446 -0.028915 1447 -0.1487 1448 -0.12967 1449 -0.039526 1450 -0.15998 1451 -0.16181 1452 -0.060231 1453 -0.24927 1454 -0.23634 1455 -0.21861 1456 -0.17976 1457 -0.16727 1458 -0.32667 1459 -0.29195 1460 -0.2333 1461 -0.32511 1462 -0.44562 1463 -0.33533 1464 -0.3114 1465 -0.23106 1466 -0.2602 1467 -0.24932 1468 -0.20005 1469 -0.1806 1470 -0.139 1471 -0.23508 1472 -0.30166 1473 -0.29893 1474 -0.099066 1475 -0.24615 1476 -0.23675 1477 -0.12987 1478 -0.1857 1479 0.014831 1480 -0.074833 1481 -0.078574 1482 -0.16734 1483 -0.10901 1484 -0.062319 1485 -0.023852 1486 -0.19452 1487 -0.094652 1488 0.0070367 1489 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