TOP
한국지구과학회
The Korean Earth Science Society

pISSN : 1225-6692  |  eISSN : 2287-4518



  • HOME
  • >
  • 누 리 집 열 람
  • >
  • 최근 논문
archives
SEARCH FOR ARTICLE
검색

kess64, vol. 38, no. 7, pp.469-480, December, 2017

Biophysical Effects Simulated by an Ocean General Circulation Model Coupled with a Biogeochemical Model in the Tropical Pacific

Biophysical Effects Simulated by an Ocean General Circulation Model Coupled with a Biogeochemical Model in the Tropical Pacific

Hyo-jin Park, Byung-kwon Moon, Jieun Wie, Ki-young Kim, Johan Lee, Young-hwa Byun

Abstract

Controversy has surrounded the potential impacts of phytoplankton on the tropical climate, since climate models produce diverse behaviors in terms of the equatorial mean state and El Nino-Southern Oscillation (ENSO) amplitude. We explored biophysical impacts on the tropical ocean temperature using an ocean general circulation model coupled to a biogeochemistry model in which chlorophyll can modify solar attenuation and in turn feed back to ocean physics. Compared with a control model run excluding biophysical processes, our model with biogeochemistry showed that subsurface chlorophyll concentrations led to an increase in sea surface temperature (particularly in the western Pacific) via horizontal accumulation of heat contents. In the central Pacific, however, a mild cold anomaly appeared, accompanying the strengthened westward currents. The magnitude and skewness of ENSO were also modulated by biophysical feedbacks resulting from the chlorophyll affecting El Nino and La Nina in an asymmetric way. That is, El Nino conditions were intensified by the higher contribution of the second baroclinic mode to sea surface temperature anomalies, whereas La Nina conditions were slightly weakened by the absorption of shortwave radiation by phytoplankton. In our model experiments, the intensification of El Nino was more dominant than the dampening of La Nina, resulting in the amplification of ENSO and higher skewness.

초록

Controversy has surrounded the potential impacts of phytoplankton on the tropical climate, since climate models produce diverse behaviors in terms of the equatorial mean state and El Nino-Southern Oscillation (ENSO) amplitude. We explored biophysical impacts on the tropical ocean temperature using an ocean general circulation model coupled to a biogeochemistry model in which chlorophyll can modify solar attenuation and in turn feed back to ocean physics. Compared with a control model run excluding biophysical processes, our model with biogeochemistry showed that subsurface chlorophyll concentrations led to an increase in sea surface temperature (particularly in the western Pacific) via horizontal accumulation of heat contents. In the central Pacific, however, a mild cold anomaly appeared, accompanying the strengthened westward currents. The magnitude and skewness of ENSO were also modulated by biophysical feedbacks resulting from the chlorophyll affecting El Nino and La Nina in an asymmetric way. That is, El Nino conditions were intensified by the higher contribution of the second baroclinic mode to sea surface temperature anomalies, whereas La Nina conditions were slightly weakened by the absorption of shortwave radiation by phytoplankton. In our model experiments, the intensification of El Nino was more dominant than the dampening of La Nina, resulting in the amplification of ENSO and higher skewness.

Keyword

El Nino-Southern Oscillation, biogeochemistry model, biophysical feedbacks, chlorophyll effects, sea surface temperature

Download

back