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Long-term trends in the distribution of ocean chlorophyll
  • Dongran Zhai,
  • Claudie Beaulieu,
  • Raphael M. Kudela
Dongran Zhai
University of California, Santa Cruz

Corresponding Author:[email protected]

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Claudie Beaulieu
University of California, Santa Cruz
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Raphael M. Kudela
University of California, Santa Cruz
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Abstract

The concentration of chlorophyll-a (CHL) is an important proxy for autotrophic biomass and primary production in the ocean. Quantifying trends and variability in CHL are essential to understanding how marine ecosystems are affected by climate change. Previous analyses have focused on assessing trends in CHL mean, but little is known about observed changes in CHL extremes and variance. Here we apply a quantile regression model to detect trends in CHL distribution over the period of 1997-2022 for several quantiles. We find that the magnitude of trends in upper quantiles of global CHL (>90th) are larger than those in lower quantiles (≤50th) and in the mean, suggesting a growing asymmetry in CHL distribution. On a regional scale, trends in different quantiles are statistically significant at high latitude, equatorial, and oligotrophic regions. Assessing changes in CHL distribution has potential to yield a more comprehensive understanding of climate change impacts on CHL.
10 Oct 2023Submitted to ESS Open Archive
14 Oct 2023Published in ESS Open Archive