报告题目一：Long-lasting marine heatwaves instigated by ocean planetary waves in the tropical Indian Ocean during 2015/16 and 2019/20
报告人：张莹，中国科学院南海海洋研究所助理研究员，主要从事环流热盐输送、水团演变、海洋热浪等研究，相关成果发表在Geophysical Research Letters、Journal of Climate、Journal of Physical Oceanography等国际期刊上。
报告摘要：Marine heatwaves (MHWs) in the tropical Indian Ocean (TIO) showed remarkable increases in duration and frequency during the satellite observing era, responding to rising sea surface temperature. Long-lasting MHWs were found in three upwelling regions of the TIO in 2015-2016 and 2019-2020, closely related to persistent downwelling oceanic planetary waves. In 2015, a prolonged MHW (149 days) in the western TIO was initiated by the downwelling Rossby waves associated with the co-occurring super El Niño and positive IOD events. In the following year, the negative IOD sustained the longest MHW (372 days) in the southeastern TIO, prompted by the eastward-propagating equatorial Kelvin waves. In 2019-2020, the two longest MHWs recorded in the southwestern TIO (275 days in 2019 and 149 days in 2020) were maintained by the downwelling Rossby waves associated with the 2019 extreme IOD. This study revealed the importance of ocean dynamics in long-lasting MHWs in the TIO.
报告题目二：Longer summers in the Northern Hemisphere under global warming
报告人：林蔚，中国科学院南海海洋研究所博士研究生，主要从事海气相互作用和气候变化相关方面的研究，相关成果发表在Climate Dynamics上。
报告摘要：Summers have become hotter in recent decades, with earlier onsets in many regions. Here, we explore changes in the summer length under global warming based on the observations and CMIP6 models, identify the influences of external forcing and internal variability, and use CMIP6 models to project variations of the future summer length. Summer is defined as when the daily mean temperature is above the 1961-1990 75th percentile for 5 consecutive days. The summer length significantly increases, and the observed trends show marked regional differences. External forcing is the main contributor to the lengthening of summer, while internal variability may explain the regional differences. Our results reveal that a 1 ℃ global surface mean temperature increase is associated with 15 days of the summer length increase during 1961-2014 in the observations, while a 1 ℃ temperature increase corresponds to 10 days of the summer length increase in CMIP6 models. CMIP6 models are also used to project the change of the summer length in the future, and it is found that the summer length will continue to increase in the future. Summer will last 142 days (175 days) under SSP2-4.5 (SSP5-8.5) scenario of global warming by the end of the 21st century, equivalent to an approximate 1.2 (1.5)-fold increase relative to that of 2014.
报告时间：2021年11月4日 15:00
报告地点：南海所2号楼 1201
腾讯会议ID（线上报告）：298 611 098
主持人：吴正超 副研究员 ，牛建伟 助理研究员
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