Support for the Radiation-Intercomparison Project as part of the Chemistry Climate Model Validation exercise (CCMVal)

辐射方案中的不确定性是气候研究中误差的一大来源。PI正在领导一项国际努力，以验证化学气候模型(CCM)中使用的辐射传输模型。该项目是SPARC CCM验证(CCMVal)练习的一部分。SPARC/WCRP认识到，CCM需要广泛的验证，并为执行这一项目提供框架，但不提供资金。这个项目的第一阶段即将完成，这项国家教育改革中心的小额赠款建议是为了支持项目的第二阶段和第三阶段。为此，PI收集和/或创建(通过从主程序中剥离辐射子例程)五个GCM和CCM辐射传输代码的离线版本。对辐射加热率和强迫进行了单剖面晴空比较，并与复杂的辐射模型计算的结果进行了比较)。这种方法需要大量的编码和调试，以使所有辐射方案在单个计算机平台上执行。与第一阶段分析的5个辐射计划相比，第二阶段将扩大与国际CCM社区的比较，并涉及更多的辐射计划(12+)。小组本身将需要执行所要求的离线计算。在模拟不同月份、不同时段的多个晴空大气廓线的离线辐射传输方案中，将比较加热率、辐射温度变化和辐射弛豫时间。为了解释方案之间的差异，记录每个代码中使用的各种参数和近似也很重要。因此，PI有必要访问建模小组几天，向他们灌输采取行动的必要性，然后招募愿意参与的科学家帮助制作和/或记录离线辐射代码。此后，各联络小组将被要求及时提交计算，并帮助解释计算结果。已经设计了一套所需的文件和计算。发现辐射方案误差的原因将是一个迭代过程，建模小组在请求时执行额外的计算。罗伯特·波特曼博士(NOAA-BOLDER)也在进行一套独立的参考计算。第三阶段将涉及CCM小组本身和我们的意见，利用第二阶段的结果来改进他们的辐射传输方案，并查看改进后的方案如何影响CCM集成。

Uncertainties in radiation schemes are a large source of error in climate studies. The PI is leading an international effort to validate the radiative transfer models used in Chemistry Climate Models (CCMs). This project is part of the SPARC CCM Validation (CCMVal) exercise. SPARC/WCRP recognise that CCMs require extensive validation and are providing the framework but not the funding to carry out this project. Phase I of this project is nearing completion and this NERC Small Grant proposal is to support Phases II and III of the project. Phase I. For this the PI collected and/or created (by stripping radiation subroutines out of main programs) offline versions of five GCM and CCM radiative transfer codes. Single profile clear sky comparisons of radiative heating rates and forcings were made and these were compared to those calculated with a sophisticated radiation model). This approach required substantial coding and debugging to get all radiation schemes performing on a single computer platform. Phase II will widen the comparison to the international CCM community and involve many more radiation schemes (12+), compared to the 5 analysed in Phase I. Groups themselves will need to perform the requested offline calculations. Heating rates, radiative temperature changes and radiative relaxation times will be compared in offline radiative transfer schemes for multiple clear-sky atmospheric profiles, simulating different months and different times of day. To explain the differences found between schemes it is also important to document the various parameterisations and approximations used in each code. Therefore it is necessary for the PI to visit modelling groups for a few days, impress on them the need for action and then to enlist willing scientists to help produce and/or document an offline radiation code. Following on from this contact groups will be required to submit calculations in a timely fashion and help with interpretation of the results. A suite of requested documentation and calculations has already been designed. Discovering causes of radiation scheme error will be an iterative process with the modelling groups performing additional calculations when requested. An independent set of reference calculations are also being performed by Dr Robert Portmann (NOAA-Bolder). Phase III will involve the CCM groups themselves with our input, employing the results from Phase II to improve their radiative transfer schemes and look at how improved schemes affect CCM integrations.