Seasonal climate summary for the southern hemisphere (autumn 2018): a weak La Niña fades, the austral autumn remains warmer and drier

IF 3.6 4区 地球科学 Q1 Earth and Planetary Sciences
Bernard Chapman, Katie Rosemond
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引用次数: 3

Abstract

This is a summary of the austral autumn 2018 atmospheric circulation patterns and meteorological indices for the southern hemisphere, including an exploration of the season’s rainfall and temperature for the Australian region. The weak La Niña event during summer 2017–18 was in retreat as the southern hemisphere welcomed the austral autumn, and before midseason, it had faded. With the El Niño Southern Oscillation and the Indian Ocean Dipole in neutral phases, their influence on the climate was weakened. Warmer than average sea surface temperatures dominated much of the subtropical South Pacific Ocean and provided favourable conditions for the formation of a rare subtropical cyclone over the southeast Pacific Ocean in May. The southern hemisphere sea ice extent was slightly below the autumn seasonal average. The southern hemisphere overall during autumn was drier and warmer than the seasonal average. The season brought warmer than average temperatures and average rains to parts of the continents of Africa and South America. Australia recorded its fourth-warmest autumn, partly due to an intense, extensive and persistent heatwave, which occurred during the midseason. An extraordinary and record-breaking rainfall event occurred over Tasmania’s southeast, under the influence of a negative Southern Annular Mode. The mainland’s northeastern tropical region was wetter than average as a result of tropical cyclones, which formed during an active monsoon. These areas, however, were in contrast to the rest of the continent, which followed the trend of the previous season and remained drier than average; consequently, rainfall deficiencies emerged across the southern half of Australia, and some areas witnessed an increase in extent and severity of these deficiencies.
南半球季节气候摘要(2018年秋季):弱La Niña减弱,南方秋季保持温暖干燥
本文总结了2018年南半球秋季的大气环流模式和南半球的气象指数,包括对澳大利亚地区该季节降雨和温度的探索。2017-18年夏季La Niña活动减弱,因为南半球迎来了南方的秋天,在季节中期之前,它已经消退。随着El Niño南方涛动和印度洋偶极子处于中性相位,它们对气候的影响减弱。副热带南太平洋大部分海域的海面温度高于平均水平,为5月东南太平洋上空形成一个罕见的副热带气旋提供了有利条件。南半球海冰范围略低于秋季季节平均水平。南半球整个秋季比季节平均更干燥、更温暖。这个季节给非洲和南美大陆的部分地区带来了比平均温度更高的气温和平均降雨量。澳大利亚录得第四热的秋天,部分原因是在季节中期发生了强烈、广泛和持续的热浪。在负南环模式的影响下,塔斯马尼亚州东南部发生了一场非同寻常的破纪录的降雨事件。由于季风活动期间形成的热带气旋,大陆东北热带地区比平均水平更潮湿。然而,这些地区与非洲大陆的其他地区形成对比,后者遵循上一季的趋势,仍然比平均水平干燥;因此,澳大利亚南半部出现了降雨不足的现象,一些地区的降雨不足程度和严重程度都有所增加。
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来源期刊
Journal of Southern Hemisphere Earth Systems Science
Journal of Southern Hemisphere Earth Systems Science Earth and Planetary Sciences-Oceanography
CiteScore
8.10
自引率
8.30%
发文量
0
审稿时长
>12 weeks
期刊介绍: The Journal of Southern Hemisphere Earth Systems Science (JSHESS) publishes broad areas of research with a distinct emphasis on the Southern Hemisphere. The scope of the Journal encompasses the study of the mean state, variability and change of the atmosphere, oceans, and land surface, including the cryosphere, from hemispheric to regional scales. general circulation of the atmosphere and oceans, climate change and variability , climate impacts, climate modelling , past change in the climate system including palaeoclimate variability, atmospheric dynamics, synoptic meteorology, mesoscale meteorology and severe weather, tropical meteorology, observation systems, remote sensing of atmospheric, oceanic and land surface processes, weather, climate and ocean prediction, atmospheric and oceanic composition and chemistry, physical oceanography, air‐sea interactions, coastal zone processes, hydrology, cryosphere‐atmosphere interactions, land surface‐atmosphere interactions, space weather, including impacts and mitigation on technology, ionospheric, magnetospheric, auroral and space physics, data assimilation applied to the above subject areas . Authors are encouraged to contact the Editor for specific advice on whether the subject matter of a proposed submission is appropriate for the Journal of Southern Hemisphere Earth Systems Science.
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