열대 태평양 지역에서의 ENSO와 연관한 해양 엽록소 변동성

Abstract

Photosynthesis by oceanic phytoplankton is believed to be responsible for the majority of the carbon cycling on this planet and they also change the albedo of the upper ocean resulting in the increase of incoming radiation. Thus, phytoplankton play a vital part in climate systems by regulating the amount of carbon dioxide in the atmosphere and by altering the intensity of solar radiation at the surface. In particular, equatorial Pacific is the largest oceanic source of carbon dioxide to the associated with equatorial upwelling and enhanced chlorophyll concentration. As a first step to understand the relationship between ocean biology and climate variability in the tropics, spatio-temporal variability of tropical chlorophyll is investigated in this study. Two principal modes of the 148-month length of chlorophyll data reveals that the variability of tropical chlorophyll is related to El-Ni;o and Southern Oscillation (ENSO). The first mode is mostly associated with the mature phase of El-Ni;o during winter, while the second mode is associated with the decaying phase of El-Ni;o during summer. The cause of the chlorophyll variability is different according to the physical characteristics of different tropical regions. That is, growth-limiting factors of phytoplankton are different in equatorial western Pacific, central Pacific, and eastern Pacific, respectively. This difference makes the nonlinear and asymmetric response of ocean biology to the ENSO. These results can be a basis for the further research on the interaction between the ocean biology and the climate variability.