An Assessment of Land-Atmosphere Interactions over South America Using Satellites, Reanalysis, and Two Global Climate Models
An Assessment of Land-Atmosphere Interactions over South America Using Satellites, Reanalysis, and Two Global Climate Models
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DOI：
10.1175/jhm-d-20-0132.1
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发表时间：
2021-04-01
影响因子：
3.8
通讯作者：
Spracklen, Dominick, V
中科院分区：
文献类型：
--
作者：
Baker, Jessica C. A.;de Souza, Dayana Castilho;Spracklen, Dominick, V
在南美洲，陆-气相互作用对气候，特别是区域水文循环有重要影响，但在全球气候模式中对这些过程的详细评价有限。聚焦于2003-14年的卫星时代，我们在卫星产品，一个新的再分析（ERA 5-土地），和两个全球气候模型：巴西全球大气模型版本1.2（BAM-1.2）和英国在南美洲的年度到季节的时间尺度上评估陆-气相互作用。哈德利中心全球环境模型第三版（HadGEM 3）。我们确定了卫星和模型数据集中代表的南美洲陆地-大气相互作用的关键特征，包括耦合强度的季节变化，蒸散对表面水分的敏感性的大尺度空间变化，以及整个大陆蒸发制度的偶极子。还确定了产品之间的差异，ERA 5-Land，HadGEM 3和BAM-1.2在亚马逊河和塞拉多的部分地区显示出与卫星相反的相互作用，以及沿北大西洋海岸沿着更强的陆-气耦合。在模型和卫星对陆地-大气相互作用的强度和方向存在分歧的情况下，降水偏差和对控制表层土壤湿度的过程的错误描述可能是驱动因素。这些结果表明，改进模型过程可以减少模拟的气候对土地利用变化的反应的不确定性，并强调模型偏差可能不切实际地放大未来气候预测中的干燥或湿润趋势。最后，HadGEM 3和BAM-1.2与9个CMIP 6模式集合的中值响应一致，表明它们广泛代表了最新一代的气候模式。
In South America, land-atmosphere interactions have an important impact on climate, particularly the regional hydrological cycle, but detailed evaluation of these processes in global climate models has been limited. Focusing on the satellite-era period of 2003-14, we assess land-atmosphere interactions on annual to seasonal time scales over South America in satellite products, a novel reanalysis (ERA5-Land), and two global climate models: the Brazilian Global Atmospheric Model version 1.2 (BAM-1.2) and the U.K. Hadley Centre Global Environment Model version 3 (HadGEM3). We identify key features of South American land-atmosphere interactions represented in satellite and model datasets, including seasonal variation in coupling strength, large-scale spatial variation in the sensitivity of evapotranspiration to surface moisture, and a dipole in evaporative regime across the continent. Differences between products are also identified, with ERA5-Land, HadGEM3, and BAM-1.2 showing opposite interactions to satellites over parts of the Amazon and the Cerrado and stronger land-atmosphere coupling along the North Atlantic coast. Where models and satellites disagree on the strength and direction of land-atmosphere interactions, precipitation biases and misrepresentation of processes controlling surface soil moisture are implicated as likely drivers. These results show where improvement of model processes could reduce uncertainty in the modeled climate response to land-use change, and highlight where model biases could unrealistically amplify drying or wetting trends in future climate projections. Finally, HadGEM3 and BAM-1.2 are consistent with the median response of an ensemble of nine CMIP6 models, showing they are broadly representative of the latest generation of climate models.