Collaborative Research: Remote Observations of Ice Sheet Surface Temperature: Toward Multi-Proxy Reconstruction of Antarctic Climate Variability

该项目将利用一种多代用指标校准/核实方法，结合冰芯中的气候信号、卫星遥感和气象站数据，对过去几个世纪南极表面温度变化进行空间上扩展和统计上可靠的估计。 从大规模古气候重建的角度来看，南极洲一直存在问题，因为缺乏长期的仪器数据，而且大多数冰芯的分辨率相对较低。 几项新的发展，特别是正在进行的国际跨南极科学考察项目的浅（~100米）冰芯网络，将产生100多年来每年解析冰芯物理特性、化学和稳定同位素数据的广泛空间覆盖。第二，现在有20多年的微波和红外线亮度温度，卫星覆盖了几乎整个南极洲，具有季节性分辨的信息，已被证明可以以非常合理的精度和准确度记录冰表面/近表面温度。 最后，先进微波扫描辐射计（AMSR）提供的微波辐射数据质量更高，空间分辨率和辐射保真度比以前的数据高得多，这将改善对南极洲长期平均温度的看法。40年的仪器记录和时间更短但空间更全面的自动气象站网络将与季节分辨率为37千兆赫的卫星相结合，基于冰表面温度的估计，以重建在过去四十年的舌形范围内的温度模式。 稀疏的南极仪器表面温度数据可以追溯到近世纪初，将被添加为长期的，虽然相当空间限制，交叉验证这些重建。这种交叉验证程序已成功地用于大约一个世纪之久的仪器记录，主要在北方半球的位置。较长的时间尺度将接近通过交叉验证的代理为基础的前20世纪世纪的表面温度重建，使用的信息，从更深的积雪，是在低频被动微波卫星测量的热辐射。 低频估计加上钻孔测温，将对年表面长期平均值提供重要的独立核实。

This project will develop spatially extended and statistically reliable estimates of Antarctic surface temperature variations over the past several centuries, using a multi-proxy calibration/verification approach that combines the climate signal in ice core, satellite remote sensing, and weather station data. Antarctica has been problematic from the point of view of large-scale paleoclimate reconstruction because of the paucity of long-term instrumental data, and the relatively low resolution of most ice cores. Several new developments, particularly the network of shallow (~100 meter) ice cores from the ongoing International Trans-Antarctic Scientific Expedition (ITASE) project will yield broad spatial coverage of annually resolved ice core physical properties, chemistry, and stable isotope data over more than a hundred years. Second, there are now over twenty years of microwave and infrared brightness temperatures available from satellites covering virtually all of Antarctica with seasonally resolved information that has been demonstrated to record the ice surface/near surface temperature with very reasonable precision and accuracy. Finally, higher quality microwave emission data from Advanced Microwave Scanning Radiometers (AMSR) with much finer spatial resolution and radiometric fidelity than those from previous sources will offer an improved view of longer term mean temperatures in Antarctica.The 40-year instrumental record and the shorter but spatially more comprehensive Automatic Weather Station network will be combined with seasonally-resolved 37-gigahertz satellite-based ice surface temperature estimates to reconstruct Antarctic-wide temperature patterns during the past forty years. The sparser Antarctic instrumental surface temperature data available back nearly to the beginning of the century will be added for longer-term, though quite spatially-restricted, cross-validation of these reconstructions. This cross-validation procedure has been used successfully with roughly century-long instrumental records at locations primarily in the Northern Hemisphere. The longer time scale will be approached through a cross-validation of the proxy-based pre-20th century surface temperature reconstructions using information on thermal emission from deeper in the firn that is contained in low-frequency passive microwave satellite measurements. The low-frequency estimates, supplemented by borehole thermometry, will provide important independent verification of the long-term averages of the annual surfac