ABSTRACT Two decades (1997–2017) of blended satellite-retrieved phytoplankton chlorophyll a concentration (Chl-a) data were used to assess the interannual variation and recent trends of phytoplankton biomass in Arctic and subarctic ocean (ASAO) regions. Satellite and reanalysis data for geophysical variables were used to assess the probable environmental factors responsible for the observed Chl-a changes. Aggregate Chl-a in the entire ASAO increased steadily from 1997 and then began to decline in the early 2010s. This decline reflects Chl-a declines in most ASAO regions, but the responsible factors and the year in which the trend reversal occurred varied greatly from region to region. In open ocean regions, large-scale climate variability might underlie the Chl-a decline, whereas, in semi-enclosed coastal waters and embayments, the underlying factors might be local or regional (including land–ocean interactions). Therefore, although sea surface temperatures in the ASAO continued to increase steadily, the decline in aggregate Chl-a in the ASAO is unlikely to be connected to global warming.

中文翻译：

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过去 20 年北极和亚北极海域卫星提取叶绿素 a 数据的时间变化

摘要 20 年（1997-2017 年）的混合卫星提取的浮游植物叶绿素 a 浓度（Chl-a）数据用于评估北极和亚北极海洋（ASAO）地区浮游植物生物量的年际变化和近期趋势。地球物理变量的卫星和再分析数据用于评估可能导致所观察到的 Chl-a 变化的环境因素。整个ASAO中的Chl-a总量从1997年开始稳步上升，然后在2010年代初开始下降。这种下降反映了大多数ASAO地区的Chl-a下降，但造成趋势逆转的原因和年份因地区而异。在开阔的海洋区域，大规模的气候变化可能是 Chl-a 下降的基础，而在半封闭的沿海水域和海湾，潜在因素可能是地方性的或区域性的（包括陆海相互作用）。因此，尽管ASAO的海面温度继续稳步上升，但ASAO中Chl-a总量的下降不太可能与全球变暖有关。