The study on stable isotopic compositions of tree rings is playing an important role in reconstructing past climatic variations on the annual scale. Recently, a higher resolution study on seasonal variation in stable ...The study on stable isotopic compositions of tree rings is playing an important role in reconstructing past climatic variations on the annual scale. Recently, a higher resolution study on seasonal variation in stable isotopic compositions of tree rings is developing. Some significant results on this aspect have been obtained, and all of them seem to respond to the moisture stress of growing season. Also, the seasonal δ <sup>13</sup>C patterns in tree展开更多
1 Materials and methods THE tree-ring reported here is one of pine discs sampled at 3 200 m a.s.l. in Qongtelian Valley in the Tuomu’er Peak region in 1978. The local geographical and climate condition has been intro...1 Materials and methods THE tree-ring reported here is one of pine discs sampled at 3 200 m a.s.l. in Qongtelian Valley in the Tuomu’er Peak region in 1978. The local geographical and climate condition has been introduced in detail. An index series was obtained after the width of tree-rings on 5 different radii was measured andfitted by linear and negative exponential functional regression. Each annual ring has been separated on the whole to simultaneously measure △<sup>14</sup> C and δ<sup>13</sup> C of treerings. Cellulose was extracted by the standard chemical method, then oxidized by copper oxide to C0<sub>2</sub>.Carbon isotopic analyses were performed with a Mat-252 mass spectrometer. Results are expressed in thestandard δ notation with respect to the PDB standard with a precision of 0.1‰. 2展开更多
文摘The study on stable isotopic compositions of tree rings is playing an important role in reconstructing past climatic variations on the annual scale. Recently, a higher resolution study on seasonal variation in stable isotopic compositions of tree rings is developing. Some significant results on this aspect have been obtained, and all of them seem to respond to the moisture stress of growing season. Also, the seasonal δ <sup>13</sup>C patterns in tree
文摘1 Materials and methods THE tree-ring reported here is one of pine discs sampled at 3 200 m a.s.l. in Qongtelian Valley in the Tuomu’er Peak region in 1978. The local geographical and climate condition has been introduced in detail. An index series was obtained after the width of tree-rings on 5 different radii was measured andfitted by linear and negative exponential functional regression. Each annual ring has been separated on the whole to simultaneously measure △<sup>14</sup> C and δ<sup>13</sup> C of treerings. Cellulose was extracted by the standard chemical method, then oxidized by copper oxide to C0<sub>2</sub>.Carbon isotopic analyses were performed with a Mat-252 mass spectrometer. Results are expressed in thestandard δ notation with respect to the PDB standard with a precision of 0.1‰. 2