Are trends in convective parameters over the United States and Europe consistent between reanalyses and observations?
Are trends in convective parameters over the United States and Europe consistent between reanalyses and observations?
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DOI：
10.1175/jcli-d-21-0135.1
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发表时间：
2022-02
影响因子：
4.9
通讯作者：
Natalia Pilguj;M. Taszarek;J. Allen;K. Hoogewind
中科院分区：
文献类型：
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作者：
Natalia Pilguj;M. Taszarek;J. Allen;K. Hoogewind
在这项工作中，对流参数的长期趋势之间的ERA 5，MERRA 2，并观察到的rawinsonde配置文件在欧洲和美国，包括周边地区进行了比较。比较使用了39年的记录（1980-2018年），其中包含84个台站在0000和1200 UTC时进行的207万次质量控制测量，沿着的是搭配的再分析剖面。总的来说，再分析提供了与观测相似的信号，但ERA 5具有较低的偏差。在欧洲，与美国的混合趋势相比，探空仪和再分析之间的趋势信号一致性更好，特别是在不稳定性（抬升指数）、低空湿度（混合比）和0-3公里直减率方面。然而，所有三个数据集和两个域的一致信号被发现对流抑制（CIN），下沉气流CAPE（DCAPE）和平均0-4公里的相对湿度下降的强劲增长。尽管各大洲之间的趋势不同，但再分析很好地捕捉到了0-6公里风切变和1-3公里平均风的变化，美国略有增加，欧洲有所减少。然而，这些变化大多微不足道。所有数据集都表明，几乎整个对流层剖面都在持续变暖，在欧洲，这是近地面最快的，而在大平原，一般在地面以上2-3公里，从而有助于CIN的增加。这项工作的结果显示了在不同数据集之间相互比较趋势的重要性，因为与一次再分析或观测相关的局限性可能会导致不确定性，并降低我们对参数如何随时间变化的信心。
In this work, long-term trends in convective parameters are compared between ERA5, MERRA2, and observed rawinsonde profiles over Europe and the United States including surrounding areas. A 39-year record (1980–2018) with 2.07 million quality-controlled measurements from 84 stations at 0000 and 1200 UTC is used for the comparison, along with collocated reanalysis profiles. Overall, reanalyses provide similar signals to observations, but ERA5 features lower biases. Over Europe, agreement in the trend signal between rawinsondes and the reanalyses is better, particularly with respect to instability (lifted index), low-level moisture (mixing ratio) and 0–3 km lapse rates as compared to mixed trends in the United States. However, consistent signals for all three datasets and both domains are found for robust increases in convective inhibition (CIN), downdraft CAPE (DCAPE) and decreases in mean 0–4 km relative humidity. Despite differing trends between continents, the reanalyses capture well changes in 0–6 km wind shear and 1–3 km mean wind with modest increases in the United States and decreases in Europe. However, these changes are mostly insignificant. All datasets indicate consistent warming of almost the entire tropospheric profile, which over Europe is the fastest near-ground, while across the Great Plains generally between 2–3 km above ground level, thus contributing to increases in CIN. Results of this work show the importance of intercomparing trends between various datasets, as the limitations associated with one reanalysis or observations may lead to uncertainties and lower our confidence in how parameters are changing over time.