Attributing Excessive Upper-Tropospheric Warm Biases in CMIP6 Models over Tropical Oceans to Missing Physical Processes: Evidence from Satellite Observations

A. Reference temperature Datasets: ta_mon_Aura-MLS-v04-2_BE_gn_200408-201012.nc The Microwave Limb Sounder (MLS) is an instrument aboard NASA’s Aura satellite, launched in 2004 as part of the Earth Observing System (EOS) program. MLS measures atmospheric temperature, pressure, and various trace gases, primarily in the upper troposphere, stratosphere, and mesosphere, using microwave limb sounding techniques (Waters et al., 2006). Operating in the microwave spectrum, MLS observes thermal emission from the atmospheric limb to derive temperature profiles with coarse vertical resolution but global coverage. We use the Version 3.3 Level 2 data (MLS 2004 v03.3) spanning 2005–2010 at 300 hPa. These data are particularly useful for evaluating upper-tropospheric temperature structure in models. Quality control and data documentation are available at http://mls.jpl.nasa.gov/data/v3-3_data_quality_document.pdf. ta_mon_GNSS-RO-1-3_BE_gn_200201-201412.nc GNSS Radio Occultation (RO) is a satellite-based remote sensing technique that uses signals from Global Navigation Satellite System (GNSS) satellites to derive high-vertical-resolution profiles of atmospheric refractivity, from which temperature, pressure, and humidity can be inferred. RO offers excellent vertical resolution (~100 m in the upper troposphere and lower stratosphere) and is less affected by calibration drift or satellite-to-satellite biases, making it ideal for long-term climate monitoring. ta_mon_AIRS-2-1_BE_gn_200209-201609-mb.nc AIRS Obs4MIPs Version 2.1 dataset (Tian & Hearty, 2020), which provides monthly mean tropospheric air temperature profiles from September 2002 to September 2016. This version includes corrections for sampling biases, improving consistency with reanalysis products. B. NCAR-DOE CESM2-CAM6 sensitivity experiments The National Center for Atmospheric Research – Department of Energy (NCAR-DOE) Community Earth System Model version 2 (CESM2) is a fully coupled climate model developed to simulate the Earth's climate system. CESM2, which incorporates the CAM6 atmospheric component, participated in CMIP6 and features an updated two-moment stratiform cloud microphysics scheme (MG2; Gettelman & Morrison, 2015). Sensitivity simulations were performed with falling ice radiative effects turned off (CESM2-NOS) and on (CESM2-SON). Both experiments were initialized from the CMIP6 preindustrial control (PiControl) run and followed the "historical" protocol from 1850 to 2014, using consistent model components, initial conditions, and prescribed external forcings (e.g., greenhouse gases, ozone, aerosols, and solar variability). The analysis in this study focuses on the 1980–2014 period. f09.CAM6.B-hist.NOS.T.plev.1980-2014-CDO_1x1.n With falling ice radiative effects turned off (CESM2-NOS) f09.CAM6.B-hist.SON.T.plev.1980-2014-CDO_1x1.nc With falling ice radiative effects turned off (CESM2-NOS)A. 参考温度数据集： ta_mon_Aura-MLS-v04-2_BE_gn_200408-201012.nc 微波临边探测器（Microwave Limb Sounder, MLS）是美国国家航空航天局（NASA）2004年作为地球观测系统（Earth Observing System, EOS）计划一部分发射的奥赖（Aura）卫星搭载的仪器。MLS采用微波临边探测技术（Waters等，2006），主要在对流层上层、平流层和中间层测量大气温度、压强与多种痕量气体。工作于微波波段的MLS通过观测大气临边的热辐射来反演温度廓线，其垂直分辨率相对较粗，但具备全球覆盖能力。 本研究使用了2005年至2010年间、对应300 hPa高度层的Version 3.3二级数据（MLS 2004 v03.3），这类数据对于评估模式中的对流层上层温度结构尤为实用。质量控制方案与数据文档可参见http://mls.jpl.nasa.gov/data/v3-3_data_quality_document.pdf。 ta_mon_GNSS-RO-1-3_BE_gn_200201-201412.nc 全球导航卫星系统无线电掩星（GNSS Radio Occultation, GNSS-RO）是一种基于卫星的遥感技术，它利用全球导航卫星系统（Global Navigation Satellite System, GNSS）的卫星信号反演获得高垂直分辨率的大气折射率廓线，进而可推演出温度、压强与湿度参数。GNSS-RO拥有优异的垂直分辨率（对流层上层和平流层下层约100米），受校准漂移或星间偏差的影响较小，非常适合长期气候监测工作。 ta_mon_AIRS-2-1_BE_gn_200209-201609-mb.nc AIRS Obs4MIPs Version 2.1数据集（Tian与Hearty，2020）提供了2002年9月至2016年9月的逐月平均对流层大气温度廓线。该版本针对采样偏差进行了校正，提升了与再分析产品的一致性。 B. NCAR-DOE CESM2-CAM6敏感性试验 美国国家大气研究中心-能源部（National Center for Atmospheric Research – Department of Energy, NCAR-DOE）的第二代社区地球系统模型（Community Earth System Model version 2, CESM2）是一款全耦合气候模式，旨在模拟地球气候系统。CESM2搭载了CAM6大气分量模块，参与了耦合模式比较计划第六阶段（Coupled Model Intercomparison Project Phase 6, CMIP6），并采用了更新的双矩量层状云微物理方案（MG2；Gettelman与Morrison，2015）。 本研究开展了两组敏感性模拟试验：分别关闭（CESM2-NOS）与开启（CESM2-SON）降冰辐射效应。两组试验均以CMIP6工业化前控制试验（CMIP6 preindustrial control, PiControl）的结果作为初始场启动，并遵循1850年至2014年的“历史”试验协议，使用一致的模式组件、初始条件以及指定的外强迫因子（如温室气体、臭氧、气溶胶与太阳活动变化）。本研究的分析聚焦于1980年至2014年时段。 f09.CAM6.B-hist.NOS.T.plev.1980-2014-CDO_1x1.n 对应试验：关闭降冰辐射效应（CESM2-NOS） f09.CAM6.B-hist.SON.T.plev.1980-2014-CDO_1x1.nc 对应试验：关闭降冰辐射效应（CESM2-NOS）