A Digital Computer Method for Dating Short Tree Ring Series

Nature ◽  
1964 ◽  
Vol 201 (4917) ◽  
pp. 412-413
Author(s):  
H. C. HOWLAND ◽  
G. SHARROCK ◽  
J. RASKIN
Keyword(s):  
Tree Ring ◽  
Digital Computer ◽  
Computer Method ◽  
Short Tree

scholarly journals Millennium-long summer temperature variations in the European Alps as reconstructed from tree rings

2010 ◽  
Vol 6 (3) ◽  
pp. 379-400 ◽  
Author(s):  
C. Corona ◽  
J. Guiot ◽  
J. L. Edouard ◽  
F. Chalié ◽  
U. Büntgen ◽  
...  
Keyword(s):  
Tree Ring ◽  
Regional Growth ◽  
Low Frequency ◽  
Warming Trend ◽  
High Elevation ◽  
Ice Age ◽  
European Alps ◽  
Linear Calibration ◽  
Late 20Th Century ◽  
Short Tree

Abstract. This paper presents a reconstruction of the summer temperatures over the Greater Alpine Region (44.05°–47.41° N, 6.43°–13° E) during the last millennium based on a network of 38 multi-centennial larch and stone pine chronologies. Tree ring series are standardized using an Adaptative Regional Growth Curve, which attempts to remove the age effect from the low frequency variations in the series. The proxies are calibrated using the June to August mean temperatures from the HISTALP high-elevation temperature time series spanning the 1818–2003. The method combines an analogue technique, which is able to extend the too short tree-ring series, an artificial neural network technique for an optimal non-linear calibration including a bootstrap technique for calculating error assessment on the reconstruction. About 50% of the temperature variance is reconstructed. Low-elevation instrumental data back to 1760 compared to their instrumental target data reveal divergence between (warmer) early instrumental measurements and (colder) proxy estimates. The proxy record indicates cool conditions, from the mid-11th century to the mid-12th century, related to the Oort solar minimum followed by a short Medieval Warm Period (1200–1420). The Little Ice Age (1420–1830) appears particularly cold between 1420 and 1820 with summers that are 0.8 °C cooler than the 1901–2000 period. The new record suggests that the persistency of the late 20th century warming trend is unprecedented. It also reveals significant similarities with other alpine reconstructions.

scholarly journals Informing Conservation: Towards 14C Wiggle-Matching of Short Tree-Ring Sequences from Medieval Buildings in England

Radiocarbon ◽  
2016 ◽  
Vol 59 (3) ◽  
pp. 985-1007 ◽  
Author(s):  
A Bayliss ◽  
P Marshall ◽  
C Tyers ◽  
C Bronk Ramsey ◽  
G Cook ◽  
...  
Keyword(s):  
Tree Ring ◽  
Historic Buildings ◽  
Calibration Data ◽  
Medieval Period ◽  
Growth Rings ◽  
Comparable Level ◽  
Annual Growth Rings ◽  
Short Tree ◽  
Oak Tree ◽  
Calendar Dates

AbstractThis study tested whether accurate dating by accelerator mass spectrometry (AMS) radiocarbon wiggle-matching of short tree-ring series (~30 annual rings) in the Medieval period could be achieved. Scientific dating plays a central role in the conservation of historic buildings in England. Precise dating helps assess the significance of particular buildings or elements of their fabric, thus allowing us to make informed decisions about their repair and protection. Consequently, considerable weight, both financial and legal, can be attached to the precision and accuracy of this dating. Dendrochronology is the method of choice, but in a proportion of cases this is unable to provide calendar dates. Hence, we would like to be able to use 14C wiggle-matching to provide a comparable level of precision and reliability, particularly on shorter tree-ring sequences (~30 annual growth rings) that up until now would not routinely be sampled. We present the results of AMS wiggle-matching five oak tree-ring sequences, spanning the period covered by the vast majority of surviving Medieval buildings in England (about AD 1180–1540) when currently we have only decadal and bidecadal calibration data.

scholarly journals A Real-Time On-Line Digital Computer Method for Monitoring Myocardial Supply: Demand Ratio

1981 ◽  
Vol 9 (1) ◽  
pp. 28-33
Author(s):  
S. L. Wood ◽  
P. A. Crosby
Keyword(s):  
Real Time ◽  
Digital Computer ◽  
Computer Method ◽  
On Line

The Myocardial Supply: Demand Ratio reflects the ratio of subendocardial perfusion to subendocardial oxygen demands. A method is described for calculating and continuously monitoring the Myocardial Supply: Demand Ratio using a digital computer in real-time.

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