Since the 1950s, scientists have measured land-based carbon uptake, primarily through plants' cellular respiration of CO₂, by gross primary production (GPP), or a measurement of the total amount of carbon that the plant uses for its own growth. The year-to-year change, or interannual variability of a region's GPP is important, because it is closely linked to weather and climate. Recently, a study revealed the influence of the air-sea teleconnection, or global circulation process on the GPP interannual variation throughout China during the spring, summer, and autumn growing seasons.

This research, led by Dr. YING Kairan and corresponding author Dr. PENG Jing from the East Asian Regional Climate and Environment Key Laboratory of the Chinese Academy of Sciences, Institute of Atmospheric Physics, Chinese Academy of Sciences hopes to provide a better understanding of year-to-year GPP fluctuations throughout China compared to ocean-atmosphere teleconnections across the Pacific and Atlantic Oceans. Their findings have just been published in Advances in Atmospheric Sciences.

The team used an ensemble of the seven-member TRENDY (Trends in Net Land–Atmosphere Carbon Exchanges) climate model to investigate China's seasonal GPP interannual variability between 1951--2010. This model allowed scientists to investigate the relationship between sea surface temperature (SST) and atmospheric circulations.

GPP can be broken down into several components, or signals, that identify the different chemical processes involved in the sugar conversion process in plants from photosynthesis. The signal that is most closely related to influencing climate is the Residual Principal Component (R-PC), which considers cellular respiration, water vapor exchange, dissolved organic carbon, and several other minor processes. Over time, R-PC is identified by separating out its significant impact from the linear trend of GPP and the GPP memory, which can give seasonal wet/dry signals through soil analysis.

Researchers broke down their analysis of seasonal GPP and R-PC throughout China into two parts, R-PC1 and R-PC2. Results show that between spring and autumn, analysis trends initially show a monopole, then trending toward a dipole or tripole spatial structure. Clear seasonal evolution is apparent considering the trends' maximum centers regarding R-PC exist between spring and summer, or the primary growing season. This means that the dominant two GPP R-PC signals are significantly related to Sea Surface Temperature (SST) variability in the eastern tropical Pacific Ocean and the North Pacific Ocean during spring to autumn.

Air-sea teleconnections play a key role in year-to-year variability of seasonal gross primary production throughout China

Likewise, the El Nino–Southern Oscillation (ENSO) and the Pacific Decadal Oscillation (PDO) teleconnections also appear to have a significant influence on GPP and R-PC. Statistically, the SST and atmospheric circulation factors identified in the study explain 13%, 23% and 19% of the total variance for seasonal GPP in spring, summer, and autumn, respectively.

Citation: Ying, K. R., J. Peng, L. Dan, and X. G. Zheng, 2022: Ocean-atmosphere teleconnections play a key role in the interannual variability of seasonal gross primary production in China. Adv. Atmos. Sci., https://doi.org/10.1007/s00376-021-1226-4.

Media contact: Ms. LIN Zheng, jennylin@mail.iap.ac.cn