...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Atmospheric chemistry and physics >Reconciling differences in stratospheric ozone composites
【24h】

Reconciling differences in stratospheric ozone composites

机译：调和平流层臭氧复合材料的差异

获取原文
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Observations of stratospheric ozone from multiple instruments now span three decades; combining these into composite datasets allows long-term ozone trends to be estimated. Recently, several ozone composites have been published, but trends disagree by latitude and altitude, even between composites built upon the same instrument data. We confirm that the main causes of differences in decadal trend estimates lie in (i)?steps in the composite time series when the instrument source data changes and (ii)?artificial sub-decadal trends in the underlying instrument data. These artefacts introduce features that can alias with regressors in multiple linear regression (MLR) analysis; both can lead to inaccurate trend estimates. Here, we aim to remove these artefacts using Bayesian methods to infer the underlying ozone time series from a set of composites by building a joint-likelihood function using a Gaussian-mixture density to model outliers introduced by data artefacts, together with a data-driven prior on ozone variability that incorporates knowledge of problems during instrument operation. We apply this Bayesian self-calibration approach to stratospheric ozone in 10° bands from 60°?S to 60°?N and from 46 to 1?hPa (～?21–48?km) for 1985–2012. There are two main outcomes: (i)?we independently identify and confirm many of the data problems previously identified, but which remain unaccounted for in existing composites; (ii)?we construct an ozone composite, with uncertainties, that is free from most of these problems – we call this the BAyeSian Integrated and Consolidated (BASIC) composite. To analyse the new BASIC composite, we use dynamical linear modelling (DLM), which provides a more robust estimate of long-term changes through Bayesian inference than MLR. BASIC and DLM, together, provide a step forward in improving estimates of decadal trends. Our results indicate a significant recovery of ozone since 1998 in the upper stratosphere, of both northern and southern midlatitudes, in all four composites analysed, and particularly in the BASIC composite. The BASIC results also show no hemispheric difference in the recovery at midlatitudes, in contrast to an apparent feature that is present, but not consistent, in the four composites. Our overall conclusion is that it is possible to effectively combine different ozone composites and account for artefacts and drifts, and that this leads to a clear and significant result that upper stratospheric ozone levels have increased since 1998, following an earlier decline.
机译：现在，用多种仪器对平流层臭氧的观测已经跨越了三十年。将它们组合到复合数据集中可以估算长期的臭氧趋势。最近，已经发布了几种臭氧复合材料，但是即使在基于相同仪器数据构建的复合材料之间，纬度和海拔高度也存在差异。我们确认年代际趋势估计值差异的主要原因在于（i）当工具源数据发生变化时复合时间序列中的步骤以及（ii）基础工具数据中的人为亚年代际趋势。这些伪像引入了可以在多元线性回归（MLR）分析中与回归变量混叠的特征。两者都可能导致不正确的趋势估计。在这里，我们的目的是通过使用高斯混合密度建立联合似然函数来建模数据假象引入的异常值以及数据驱动的贝叶斯方法，从而从一组复合物中推断出这些臭氧假象，从而从一组复合物中推断出底层臭氧时间序列。臭氧变化的先验知识，结合了仪器操作过程中的问题知识。我们将这种贝叶斯自校准方法应用于1985-2012年在60°S到60°N的10°波段和46到1？hPa（〜21-48？km）的10°波段的平流层臭氧中。主要有两个结果：（i）我们独立地确定并确认了先前确定的许多数据问题，但是在现有组合中仍未解决这些问题; （ii）？我们构建了一个不确定的臭氧复合材料，其中没有大多数此类问题-我们将其称为BAyeSian集成和整合（BASIC）复合材料。为了分析新的BASIC复合材料，我们使用动态线性建模（DLM），它通过贝叶斯推断比MLR提供了更可靠的长期变化估计。 BASIC和DLM一起为改进年代际趋势的估计提供了一个进步。我们的结果表明，自1998年以来，北纬和南纬中纬度地区的平流层上部臭氧均得到了显着回收，其中包括所有四种复合材料，尤其是BASIC复合材料。 BASIC结果还表明，在中纬度恢复中没有半球差异，这与四种复合物中存在但不一致的明显特征相反。我们的总体结论是，可以有效地结合使用不同的臭氧复合物并解释人为因素和漂移，这导致了一个明显而显着的结果，即平流层上层臭氧的水平自1998年以来有所下降，但随后有所下降。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号