The early instrumental warm-bias: a solution for long central European temperature series 1760-2007
The early instrumental warm-bias: a solution for long central European temperature series 1760-2007
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DOI：
10.1007/s10584-009-9649-4
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发表时间：
2010-07-01
期刊：
影响因子：
4.8
通讯作者：
Maugeri, Maurizio
中科院分区：
文献类型：
--
作者：
Boehm, Reinhard;Jones, Philip D.;Maugeri, Maurizio
大阿尔卑斯山地区(GAR)的仪器温度记录始于1760年。在1850年至1870年之前，不同类型的屏风保护仪器，温度计不能充分遮挡阳光直射，因此通常放置在朝北的墙上或窗户上。很可能是夏季半年的气温偏暖，冬季的气温偏冷，夏季效应占主导地位。由于转换到屏幕的时间通常相似，往往与国家气象局在全球气象局的成立同时发生，因此很难确定问题的严重程度，因为所有邻近地点都可能受到类似的影响。本文使用奥地利克雷姆斯蒙斯特老遗址和现代遗址近八年来的同步测量来评估这一问题。两个地点(遮挡和未遮挡)之间的温差导致了日循环的变化，这取决于一年中的不同时间。从该地区唯一仍然存在和活跃的早期仪器测量点的这一具体经验证据出发，我们发展了NW向到N向到NE向的三种校正模型。使用从该区域其他早期仪器站点(从东北到西北方向的GAR的站点)的站点历史中的元数据得出的建筑物的方位角，对每个位置的日周期进行了不同的调整。由于NMSS使用不同的公式根据每天在每个站点进行的两次或两次以上的观测来计算月平均值，因此对整个GAR的32个站点的影响各不相同。这些公式也随着时间的推移而变化，因此必须收集大量额外的元数据，以便在整个网络中应用调整。总体而言，结果表明，1850年前，夏季(4月至9月)的平均气温降低了约0.4摄氏度，冬季(10月至3月)基本保持不变。对月平均气温影响最大的是6月份(根据地点的不同，降温幅度从0.21摄氏度降至0.93摄氏度)到2月份一些地点略有变暖(高达0.3摄氏度)。除了修正过去几个世纪的温度演变外，这些结果还对该地区替代气候数据(如树木年轮指数和葡萄采收期等文献数据)的校准具有重要意义。GAR中32个地点的差异序列表明，自1760年以来，夏季的变暖幅度比冬季低约1摄氏度。
Instrumental temperature recording in the Greater Alpine Region (GAR) began in the year 1760. Prior to the 1850-1870 period, after which screens of different types protected the instruments, thermometers were insufficiently sheltered from direct sunlight so were normally placed on north-facing walls or windows. It is likely that temperatures recorded in the summer half of the year were biased warm and those in the winter half biased cold, with the summer effect dominating. Because the changeover to screens often occurred at similar times, often coincident with the formation of National Meteorological Services (NMSs) in the GAR, it has been difficult to determine the scale of the problem, as all neighbour sites were likely to be similarly affected. This paper uses simultaneous measurements taken for eight recent years at the old and modern site at Kremsmunster, Austria to assess the issue. The temperature differences between the two locations (screened and unscreened) have caused a change in the diurnal cycle, which depends on the time of year. Starting from this specific empirical evidence from the only still existing and active early instrumental measuring site in the region, we developed three correction models for orientations NW through N to NE. Using the orientation angle of the buildings derived from metadata in the station histories of the other early instrumental sites in the region (sites across the GAR in the range from NE to NW) different adjustments to the diurnal cycle are developed for each location. The effect on the 32 sites across the GAR varies due to different formulae being used by NMSs to calculate monthly means from the two or more observations made at each site each day. These formulae also vary with time, so considerable amounts of additional metadata have had to be collected to apply the adjustments across the whole network. Overall, the results indicate that summer (April to September) average temperatures are cooled by about 0.4A degrees C before 1850, with winters (October to March) staying much the same. The effects on monthly temperature averages are largest in June (a cooling from 0.21A degrees to 0.93A degrees C, depending on location) to a slight warming (up to 0.3A degrees C) at some sites in February. In addition to revising the temperature evolution during the past centuries, the results have important implications for the calibration of proxy climatic data in the region (such as tree ring indices and documentary data such as grape harvest dates). A difference series across the 32 sites in the GAR indicates that summers since 1760 have warmed by about 1A degrees C less than winters.