Climate Feedback of bio-geochemical processes in the Arctic

• Main Author: 임형규
• Other Authors: 일반대학원 환경공학부
• Format: Thesis
• Language: English
• Published: 포항공과대학교 2019
• Subjects: Arctic; Climate change; Phytoplankton
• Online Access: http://postech.dcollection.net/common/orgView/200000178494; https://oasis.postech.ac.kr/handle/2014.oak/111818

Doctor The Arctic warming affects the decreasing marine phytoplankton mass in future climate. The Arctic warming is also affected by changing the marine phytoplankton via absorbing more shortwave radiation and in turn radiative redistribution in the upper ocean layer, so-called bio-geophysical feedback. Thus, understanding the two-way interaction between marine biology and climate system is important to predict the Arctic climate change. This characteristic of absorbing shortwave heating of marine phytoplankton leads to conceive new natures and features in point of view moving on bio–climate interaction between marine biology, ocean, and atmosphere. However, previous works were majorly focusing on mean chlorophyll changes and its linear impact of bio-geophysical feedback and assuming the closed system of marine biogeochemical cycle. So, these studies couldn’t have clearly comprehended seasonal evolution of chlorophyll, nonlinear impact of bio-geophysical feedback, and the impact of nitrogen emission by human activity its Arctic climate feedback. In this dissertation, the evolutions, and responses of Arctic phytoplankton activity in sub-seasonal to seasonal timescales, and its bio-geophysical feedback processes in the present-day and future climates were investigated by model simulations using a Geophysical Fluid Dynamics Laboratory (GFDL) CM2.1 earth system model (ESM). This model shows one of the best model to represent the surface chlorophyll distributions. Results of historical run and Representative Concentration Pathway 4.5 (RCP4.5) scenario in the fifth’s Coupled Model Intercomparison Project (CMIP5) models are discussed in this dissertation to support the results of single model experiments. The thesis consists of three parts. The presence of interannual chlorophyll variability reduced the absorption rate of shortwave heating in the Arctic climate. This interannual chlorophyll variability was decreased in future climate, which amplified the Arctic warming. The human-induced emission of nitrogen ...