The present study examines the representation of interannual and decadal variability of sea level over the Indo-Pacific region in the Coupled Model Intercomparison Project Phase 5 (CMIP5) historical simulations and future projections. The thermocline ridge region of the Indian Ocean (TRIO) shows strong sea level variability on both the interannual and decadal timescales in the CMIP5 historical simulations. Meanwhile, prominent interannual variability is seen in the tropical western Pacific and central to eastern equatorial Pacific, whereas, the decadal sea level variability is dominant in the North Pacific and western Pacific regions. CMIP5 models project similar spatial patterns of sea level variability over the Indo-Pacific region for the twenty-first century under the mid-range and high future emission scenarios, although with some differences in the amplitude and inter-model disagreement. In the interannual timescale, there is a regional contrast in the projected future variability between the Pacific (with increase in variability with increasing greenhouse gas emissions) and TRIO (with decrease of ~ 6 % variability), which is evident in both RCP4.5 and RCP8.5 future emission scenarios with inter-model consensus. On the other hand, increase in decadal sea level variability (~ 6 % and ~ 8 % in RCP4.5 and RCP8.5 scenarios respectively) is projected over the North Pacific region (north of 30°N). In the Indian Ocean, increase in decadal sea level variability is projected over the northwestern region including Arabian Sea, though it is not a region of large decadal variability (in the reanalysis and historical simulations). Analysis revealed that the local wind forcing (wind stress curl) plays a dominant role in the sea level variability over the Indo-Pacific region on both interannual and decadal timescales.

本研究在耦合模型比较项目阶段5（CMIP5）的历史模拟和未来预测中研究了印度太平洋地区海平面年际和年代际变化的表示。在CMIP5历史模拟中，印度洋（TRIO）的跃层脊区域在年际和年代际尺度上均表现出强烈的海平面变化。同时，在热带西太平洋和赤道中部至东部赤道太平洋出现了明显的年际变化，而在北太平洋和西太平洋地区，年代际海平面变化占主导。CMIP5模型预测了在二十世纪中叶和未来高排放情景下印度太平洋区域海平面变化的相似空间格局，尽管幅度和模型间差异存在一些差异。在年际时间尺度上，太平洋地区（随着温室气体排放量的增加而变化性增加）和TRIO（随着变化性降低约6％）之间的预计未来变化存在区域差异，这在RCP4.5和具有模型间共识的RCP8.5未来排放情景。另一方面，预计北太平洋地区（北纬30°以北）的年代际海平面变化将增加（在RCP4.5和RCP8.5情景中分别为6％和8％）。在印度洋，尽管不是一个年代际变化大的地区（在重新分析和历史模拟中），但预计西北地区包括阿拉伯海的年代际海平面变化将增加。