Zhetao Tan

Zhetao Tan

he/him

Ph.D. in Meteorology

Talks and presentations

See a map of all the places I've given a talk!

气候灾害风险评估助力气候变化适应进程

April 28, 2024

talk, 2024年气候行动与减灾青年论坛, Beijing, China

受邀作为青年嘉宾参与论坛，分享了气候灾害风险评估对推动气候变化适应进程的意义。分享强调了气候灾害的广泛影响，包括海洋热浪对海洋生态的威胁及复合极端气候事件（如威尼斯洪水）对经济造成的损失。依据IPCC评估框架，报告讨论了气候风险的多维度评估重要性，并以海水养殖业为例分析其气候致灾风险。此外，还探讨了气候减灾策略与国际合作机制，如《联合国仙台减灾框架》等。最后，报告强调了青年在气候减灾和适应方面赋能气候行动的担当和责任，并鼓励青年持续思考气候减灾与适应行动的相互作用及在各行业的具体实施措施。

A new ocean data quality control system reveals a stronger ocean warming rate

July 16, 2023

talk, IUGG 2023, Berlin, Germany

Over the past century, more than 20 million in-situ profiles with heterogeneous quality had been collected, leading to a high demand of a quality control (QC) procedure to identify outliers efficiently, accurately, and automatically. In this study, we present a new automatic QC system (namely CODC-QC) for ocean temperature and salinity observations. Unlike many existing QC procedures, no assumption is made of a Gaussian distribution law in CODC-QC as the statistical distribution of the variables are typically skewed. Instead, the 99% quantiles are used as thresholds to define the local climatological ranges. In addition, these thresholds are time-varying, which aims at reducing erroneously excluding good real-time data. The above strategies are used in the local climatological range check for temperature, salinity and vertical temperature gradient, in which the anisotropic feature of water properties and the topography barriers adjustment is accounted for. Additionally, the CODC-QC under the benchmark evaluation was applied to all temperature and salinity profiles in the World Ocean Database from 1940 to 2021. Result shows a significant dependency of the quality on instrumentation types. Finally, as ocean heat content (OHC) is a fundamental indicator of climate change, the impact of different QC systems on OHC estimation is examined. We found that applying CODC-QC will lead to a 15% stronger warming rate within 1991–2021 compared to the application of WOD-QC (NOAA/NCEI), implying a non-negligible source of error in OHC estimate. The new AutoQC system could support further improvement of the ocean sciences and other applications.

Duplicate checking task team: progress and future work

July 08, 2023

talk, International Quality-Controlled Ocean Database (IQuOD) steering team meeting, Potsdam, Germany

As a task team leader of ‘duplicate checking’ group to develop an automatic duplicate checking algorithm for ocean profiles with robustness examination. The duplicate checking results have been incorporated into the World Ocean Database (WOD).

Toward a practical quantification of uncertainty in ocean heat content (OHC) due to data quality control (QC) procedures

February 26, 2022

Talks, Ocean Sciences Meeting 2022, Hawaii, USA

Ocean heat content (OHC) is a fundamental indicator for climate change. Understanding and quantifying the uncertainty in OHC record and the underlyinggridded product is an essential work. One of the uncertainty (error) sources is the Quality-Control process (QC). However, the quantitative estimate on this uncertainty source is missing to our knowledge.