CAJ | 학술논문

本文基于GRAPES全球模式的短期预报误差样本，利用赤道波动正规模态研究了热带风、压场平衡特征，并根据这些特征分析了线性平衡方程（LBE）在该区域应用时存在的问题。结果表明：（1）赤道波动能成功解释热带短期预报误差样本的大部分分量，对流层中层为60%～80%，对流层顶和平流层低层为80%以上。（2）在可解释的误差方差中，赤道罗斯贝波（ER）占比仅为30%～55%，其他赤道波动的作用不可忽视。（3）在ER模态基础上引入其他赤道波动会大幅削弱原有风、压场平衡约束，重力惯性波与Kelvin波的作用最为显著。此时，对流层中层位势高度h与u风、v风间的约束接近于零，而平流层低层h–u的平衡特征由Kelvin波主导。（4）LBE主要表达了 ER 模态下的风、压场平衡特征，与实际情形相比高估了热带风、压场的耦合程度，进一步的改进中需削弱这一虚假平衡，使得热带风、压场分析变得更加独立。
본문기우GRAPES전구모식적단기예보오차양본，이용적도파동정규모태연구료열대풍、압장평형특정，병근거저사특정분석료선성평형방정（LBE）재해구역응용시존재적문제。결과표명：（1）적도파동능성공해석열대단기예보오차양본적대부분분량，대류층중층위60%～80%，대류층정화평류층저층위80%이상。（2）재가해석적오차방차중，적도라사패파（ER）점비부위30%～55%，기타적도파동적작용불가홀시。（3）재ER모태기출상인입기타적도파동회대폭삭약원유풍、압장평형약속，중력관성파여Kelvin파적작용최위현저。차시，대류층중층위세고도h여u풍、v풍간적약속접근우령，이평류층저층h–u적평형특정유Kelvin파주도。（4）LBE주요표체료 ER 모태하적풍、압장평형특정，여실제정형상비고고료열대풍、압장적우합정도，진일보적개진중수삭약저일허가평형，사득열대풍、압장분석변득경가독립。
AbstractUsing equatorial wave modes and short-range forecast error samples of the global GRAPES (global/regional assimilation and prediction system) model, this study investigated the balance characteristics of mass and wind fields in the tropics and analyzed the problem of imposition of the Linear Balance Equation (LBE) in the tropics based on such characteristics. The results show the following: (1) Equatorial wave modes can explain a substantial fraction of the tropical forecast error variance, which ranges from 60%–80% in the mid-troposphere to more than 80% in the tropopause and lower stratosphere. (2) Only 30%–55% of the explained variance can be represented by the Equatorial Rossby wave (ER) modes, suggesting that contributions of other equatorial waves should not be ignored. (3) Based on the ER modes, introducing other equatorial waves, especially inertial-gravity and Kelvin wave modes, greatly reduces the coupling between the mass and wind. In this situation, the correlation between geopotential height and wind is close to zero in the mid-troposphere, and the correlation between geopotential height and zonal wind in the lower stratosphere is dominated by Kelvin wave modes. (4) The coupling between mass and wind was overestimated when using LBE in the tropics, because LBE mainly expresses the balance characteristics of the ER modes. Therefore, when LBE is used as the balance constraint, extra steps should be taken to reduce the fallacious correlation and allow for a decoupling of mass and wind in the tropics.