海洋上层起一个巨大的热汇（吸热装置）的作用，吸收了人类活动所排放的温室气体产生的绝大部分过剩能量。这使得海洋热含量潜在成为气候变化的一个关键指标。但要使其能够用于评估全球能量平衡及作为气候模型的一个限制条件，我们就需要对这样一个关键指标在测量上的不确定性有很好的了解。
目前，海洋热吸收的幅度具有高度不确定性，关于年际变化模式的估计值尤其相差较大。在一项重大国际合作研究中，Lyman等人对能够获得的上层海洋热含量异常曲线进行了比较，同时分析了与它们相关的不确定性的来源，包括在校正一次性深海温度测量器的数据所存在的偏差时面临的困难。
他们发现，尽管存在不确定性，但有明确而可靠的证据证明，在1993年和2008年间存在一个每平方米0.64瓦特的变暖趋势。 （生物谷Bioon.com）
生物谷推荐原文出处：
Nature doi:10.1038/nature09043
Robust warming of the global upper ocean
John M. Lyman1,2, Simon A. Good3, Viktor V. Gouretski4, Masayoshi Ishii5,6, Gregory C. Johnson2, Matthew D. Palmer3, Doug M. Smith3 & Josh K. Willis7
1 Joint Institute for Marine and Atmospheric Research, University of Hawaii at Manoa, Honolulu, Hawaii 96822, USA
2 NOAA/Pacific Marine Environmental Laboratory, Seattle, Washington 98115-6349, USA
3 Met Office Hadley Centre, Exeter EX1 3PB, UK
4 KlimaCampus, University of Hamburg, Grindelberg 5, 20144 Hamburg, Germany
5 Climate Research Department, Meteorological Research Institute, 1-1 Nagamine, Tsukuba, Ibaraki 305-0052, Japan
6 Japan Agency for Marine-Earth Science and Technology, 3173-25 Showa-machi, Kanazawa-ku, Yokohama 236-0001, Japan
7 Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91109, USA
A large (~1023?J) multi-decadal globally averaged warming signal in the upper 300?m of the world’s oceans was reported roughly a decade ago1 and is attributed to warming associated with anthropogenic greenhouse gases2, 3. The majority of the Earth’s total energy uptake during recent decades has occurred in the upper ocean3, but the underlying uncertainties in ocean warming are unclear, limiting our ability to assess closure of sea-level budgets4, 5, 6, 7, the global radiation imbalance8 and climate models5. For example, several teams have recently produced different multi-year estimates of the annually averaged global integral of upper-ocean heat content anomalies (hereafter OHCA curves) or, equivalently, the thermosteric sea-level rise5, 9, 10, 11, 12, 13, 14, 15, 16. Patterns of interannual variability, in particular, differ among methods. Here we examine several sources of uncertainty that contribute to differences among OHCA curves from 1993 to 2008, focusing on the difficulties of correcting biases in expendable bathythermograph (XBT) data. XBT data constitute the majority of the in situ measurements of upper-ocean heat content from 1967 to 2002, and we find that the uncertainty due to choice of XBT bias correction dominates among-method variability in OHCA curves during our 1993–2008 study period. Accounting for multiple sources of uncertainty, a composite of several OHCA curves using different XBT bias corrections still yields a statistically significant linear warming trend for 1993–2008 of 0.64?W?m-2 (calculated for the Earth’s entire surface area), with a 90-per-cent confidence interval of 0.53–0.75?W?m-2.
