Least-squares fitting smooth curves to decadal radiocarbon calibration data from AD 1145 to AD 1945

Smoothed curves are least-squares fitted to three sets of decadal radiocarb on calibration data from New Zealand and British Isles (AD 1725-1935) and w estern North America (AD 1145-1945). The curves are compared with each othe r and with a curve previously calculated from New Zealand data (AD 1335-174 5). The smoothing procedure results in reduced standard deviations of the c urves, but at the expense of time resolution. The comparison shows a variab le C-14 Offset between the northern and southern hemispheres of 0-70 years (Southern Hemisphere older), and a Northern Hemisphere longitudinal variati on of -20 to +60 years (British Isles generally older than western North Am erica).