SOLA ( IF 1.9 ) Pub Date : 2020-06-27 , DOI: 10.2151/sola.16a-003 Shuhei Matsugishi 1 , Hiroaki Miura 2 , Tomoe Nasuno 3 , Masaki Satoh 1
We show that a modification to the latent heat flux (LHF) formulation in Non-hydrostatic Icosahedral Atmospheric Model (NICAM) impacts the representation of a Madden–Julian oscillation (MJO) event during the Pre-Years of the Maritime Continent (Pre-YMC) field campaign in 2015. First, we compare the LHFs computed by the standard NICAM setting with those estimated from the ship observation during Pre-YMC. In this comparison, the NICAM LHF is smaller than observation in the low wind speed region and larger in the high wind speed region. Consequently, the MJO signal weakens when it passes over the Maritime Continent (MC). Next, sensitivity experiments are conducted with a modification to the threshold minimum wind speed in the bulk formula, to enhance the LHFs in the low wind speed region. With this modification, propagation of the MJO is better simulated over the MC, although a bias still remains without corrections in the high wind speed regions. This result indicates that increasing the LHF in the low wind speed region likely contributes to a more effective accumulation of moisture over the eastern MC region and consequently allows the MJO to pass over the MC in the model.
中文翻译:
使用全球云系统解析模型,潜热通量修改对2015年基督教青年会运动期间Madden-Julian振荡事件再现的影响
我们表明,在非静水二十面体大气模型(NICAM)中对潜热通量(LHF)公式的修改会影响海事大陆(Pre-YMC)年前期的Madden-Julian振荡(MJO)事件的表示)2015年的野外活动。首先,我们将标准NICAM设置计算出的LHF与YMC之前在舰船观测中估算的LHF相比较。在该比较中,NICAM LHF在低风速区域小于观测值,而在高风速区域大于观测值。因此,MJO信号经过海事大陆(MC)时会减弱。接下来,进行敏感性实验,对体积公式中的最小风速阈值进行修改,以增强低风速区域中的LHF。通过此修改,尽管在高风速区域没有进行校正,仍然存在偏见,但可以更好地模拟MC上MJO的传播。该结果表明,在低风速区域增加LHF可能有助于更有效地积聚东部MC区域内的水分,从而使MJO越过模型中的MC。