美国科罗拉多大学Jones, Tyler R的课题组取得一项新突破。他们在研究全新世期间南极洲西部的季节温度方面取得了新进展。相关论文发表在2023年1月11日出版的《自然》杂志上。

研究人员分析了来自南极西部冰原上分割冰芯的水同位素比率的连续记录，以揭示过去11000年的夏季和冬季温度变化。全新世早期到中期，南极洲西部的夏季气温不断上升，在4100年前达到温度顶峰，然后到现在持续下降。气候模型模拟显示，这些变化主要反映了夏季最大日照的变化，证实了季节日照与变暖之间存在普遍联系，并证明了日照强度的重要性，而不是季节综合日照或季节持续时间的影响。

冬季气温总体变化较小，与强迫日射量的预测一致，由于经向热输送的变化，在全新世早期也有波动。自全新世早期以来，夏季和冬季温度变化的幅度限制了南极西部冰盖表面的下降，下降幅度小于162米，可能低于58米，与南极洲西部其他地方的地质限制相一致。

研究人员表示，由于自然平滑过程、不连续性和测量分辨率的限制，具有季节分辨率的长期气候指标记录的恢复是罕见的。然而，作为数百万年尺度气候变化的主要驱动因素，强迫日射量通过季节变化对季节气候产生直接影响。季节性气候对日照是否具有敏感性并符合理论预测，还没有在长时间尺度上进行评估。

附：英文原文

Title: Seasonal temperatures in West Antarctica during the Holocene

Author: Jones, Tyler R., Cuffey, Kurt M., Roberts, William H. G., Markle, Bradley R., Steig, Eric J., Stevens, C. Max, Valdes, Paul J., Fudge, T. J., Sigl, Michael, Hughes, Abigail G., Morris, Valerie, Vaughn, Bruce H., Garland, Joshua, Vinther, Bo M., Rozmiarek, Kevin S., Brashear, Chloe A., White, James W. C.

Issue&Volume: 2023-01-11

Abstract: The recovery of long-term climate proxy records with seasonal resolution is rare because of natural smoothing processes, discontinuities and limitations in measurement resolution. Yet insolation forcing, a primary driver of multimillennial-scale climate change, acts through seasonal variations with direct impacts on seasonal climate. Whether the sensitivity of seasonal climate to insolation matches theoretical predictions has not been assessed over long timescales. Here, we analyse a continuous record of water-isotope ratios from the West Antarctic Ice Sheet Divide ice core to reveal summer and winter temperature changes through the last 11,000years. Summer temperatures in West Antarctica increased through the early-to-mid-Holocene, reached a peak 4,100years ago and then decreased to the present. Climate model simulations show that these variations primarily reflect changes in maximum summer insolation, confirming the general connection between seasonal insolation and warming and demonstrating the importance of insolation intensity rather than seasonally integrated insolation or season duration. Winter temperatures varied less overall, consistent with predictions from insolation forcing, but also fluctuated in the early Holocene, probably owing to changes in meridional heat transport. The magnitudes of summer and winter temperature changes constrain the lowering of the West Antarctic Ice Sheet surface since the early Holocene to less than 162m and probably less than 58m, consistent with geological constraints elsewhere in West Antarctica.

DOI: 10.1038/s41586-022-05411-8

Source: https://www.nature.com/articles/s41586-022-05411-8