Ozone database in support of CMIP5 simulations: results and corresponding radiative forcing
Ozone database in support of CMIP5 simulations: results and corresponding radiative forcing
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DOI：
10.5194/acp-11-11267-2011
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发表时间：
2011-01-01
影响因子：
6.3
通讯作者：
Waugh, D. W.
中科院分区：
文献类型：
--
作者：
Cionni, I.;Eyring, V.;Waugh, D. W.
已经生成了一个连续的对流层和平流层垂直分辨的臭氧时间序列，从1850年到2099年，用于不包括相互作用化学的全球气候模型中的强迫作用。SAGE I+II卫星观测和极地臭氧探测仪测量的多元线性回归分析用于1979年至2009年观测期间的平流层纬向平均数据集。除了描述平均年周期的术语外，回归还包括代表等效平流层氯（EESC）和11年太阳周期变率的术语。EESC回归拟合系数，连同1979年前的EESC值，被用来外推平流层臭氧时间序列向后到1850年。虽然可以使用类似的程序来推断未来，但耦合化学气候模型的模拟表明，未来平流层臭氧丰度可能会受到气候变化的重大影响，通过回归模型方法来捕捉这种影响是不可行的。因此，平流层臭氧数据集被扩展到未来（于2009年合并），其中13个国家气候模型的多模式平均预测在第二轮化学-气候模型验证（CCMVal-2）活动中根据SRES（排放情景特别报告）A1 B温室气体情景和A1调整卤素情景进行了模拟，直到2099年。平流层纬向平均臭氧时间序列与从两个CCM（CAM3.5和GISS-PUCCINI）过去模拟和一个CCM（CAM3.5）未来模拟中提取的三维对流层数据集合并。未来的对流层臭氧时间序列将延续CAM3.5的历史模拟，直到2099年，遵循四种不同的代表性浓度路径（RCP）。臭氧数据库的历史部分与卫星观测结果之间总体上一致性良好，但应当指出，春季期间南极纬度地区的臭氧气柱总量被高估，对流层臭氧气柱则被略微低估。对流层臭氧的垂直廓线与臭氧探测仪和现场测量结果大体一致，但在生物质燃烧区域存在一些偏差。1850 ~ 2000年对流层臭氧辐射强迫（RF）为0.23Wm（-2），低于前人的结果。数值较低的主要原因是：（一）生物质燃烧排放量的增加较小;（二）平流层臭氧消耗对南部高纬度对流层上层臭氧的影响较大;以及（三）与以前的辐射强迫计算相比，云的影响较大（云的作用是减少净强迫）。在同一时期，平流层臭氧的减少，主要是在高纬度地区，产生了-0.08W m（-2）的RF，这比政府间气候变化专门委员会（IPCC）第四次评估报告（AR 4）的核心值-0.05W m（-2）更负，但在-0.15至+0.05W m（-2）的范围内。之所以出现负值，是因为回归模型模拟了1979年之前的臭氧严重消耗，这与EESC的增加是一致的，并得到了CCM的确认，而第四次评估报告假设1979年之前平流层RF没有变化。类似量级的负RF持续到未来，尽管其位置从高纬度转移到热带，这是由于极地平流层臭氧增加，而热带低平流层臭氧减少，这与Brewer-Dobson环流的加强有关，特别是在世纪后半叶。四个区域气候方案之间对流层臭氧趋势的差异主要是由不同的甲烷浓度造成的，导致到2100年对流层臭氧RF介于0.4和0.1W m（-2）之间。此处所述的臭氧数据集已在PCMDI网站（http：//cmip-pcmdi.llnl.gov/）上发布，用于netCDF气候和预报元数据公约中的耦合模式相互比较项目（CMIP 5）模式模拟。
A continuous tropospheric and stratospheric vertically resolved ozone time series, from 1850 to 2099, has been generated to be used as forcing in global climate models that do not include interactive chemistry. A multiple linear regression analysis of SAGE I+II satellite observations and polar ozonesonde measurements is used for the stratospheric zonal mean dataset during the well-observed period from 1979 to 2009. In addition to terms describing the mean annual cycle, the regression includes terms representing equivalent effective stratospheric chlorine (EESC) and the 11-yr solar cycle variability. The EESC regression fit coefficients, together with pre-1979 EESC values, are used to extrapolate the stratospheric ozone time series backward to 1850. While a similar procedure could be used to extrapolate into the future, coupled chemistry climate model (CCM) simulations indicate that future stratospheric ozone abundances are likely to be significantly affected by climate change, and capturing such effects through a regression model approach is not feasible. Therefore, the stratospheric ozone dataset is extended into the future (merged in 2009) with multi-model mean projections from 13 CCMs that performed a simulation until 2099 under the SRES (Special Report on Emission Scenarios) A1B greenhouse gas scenario and the A1 adjusted halogen scenario in the second round of the Chemistry-Climate Model Validation (CCMVal-2) Activity. The stratospheric zonal mean ozone time series is merged with a three-dimensional tropospheric data set extracted from simulations of the past by two CCMs (CAM3.5 and GISS-PUCCINI) and of the future by one CCM (CAM3.5). The future tropospheric ozone time series continues the historical CAM3.5 simulation until 2099 following the four different Representative Concentration Pathways (RCPs). Generally good agreement is found between the historical segment of the ozone database and satellite observations, although it should be noted that total column ozone is overestimated in the southern polar latitudes during spring and tropospheric column ozone is slightly underestimated. Vertical profiles of tropospheric ozone are broadly consistent with ozonesondes and in-situ measurements, with some deviations in regions of biomass burning. The tropospheric ozone radiative forcing (RF) from the 1850s to the 2000s is 0.23Wm(-2), lower than previous results. The lower value is mainly due to (i) a smaller increase in biomass burning emissions; (ii) a larger influence of stratospheric ozone depletion on upper tropospheric ozone at high southern latitudes; and possibly (iii) a larger influence of clouds (which act to reduce the net forcing) compared to previous radiative forcing calculations. Over the same period, decreases in stratospheric ozone, mainly at high latitudes, produce a RF of -0.08W m(-2), which is more negative than the central Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report (AR4) value of -0.05W m(-2), but which is within the stated range of -0.15 to +0.05W m(-2). The more negative value is explained by the fact that the regression model simulates significant ozone depletion prior to 1979, in line with the increase in EESC and as confirmed by CCMs, while the AR4 assumed no change in stratospheric RF prior to 1979. A negative RF of similar magnitude persists into the future, although its location shifts from high latitudes to the tropics.This shift is due to increases in polar stratospheric ozone, but decreases in tropical lower stratospheric ozone, related toa strengthening of the Brewer-Dobson circulation, particularly through the latter half of the 21st century. Differences in trends in tropospheric ozone among the four RCPs are mainly driven by different methane concentrations, resulting in a range of tropospheric ozone RFs between 0.4 and 0.1W m(-2) by 2100. The ozone dataset described here has been released for the Coupled Model Intercomparison Project (CMIP5) model simulations in netCDF Climate and Forecast (CF) Metadata Convention at the PCMDI website (http://cmip-pcmdi.llnl.gov/).