Research and Educatin Center for Natural Sciences/Department of Physics, Keio University, Yokohama, 223-8521, Japan.
Application Laboratory, Japan Agency for Marine-Earth Science and Technology, Yokohama, 236-0001, Japan.
Sci Rep. 2017 Aug 24;7(1):9321. doi: 10.1038/s41598-017-09461-1.
The size and mass of Venus is similar to those of the Earth; however, its atmospheric dynamics are considerably different and they are poorly understood due to limited observations and computational difficulties. Here, we developed a data assimilation system based on the local ensemble transform Kalman filter (LETKF) for a Venusian Atmospheric GCM for the Earth Simulator (VAFES), to make full use of the observational data. To examine the validity of the system, two datasets were assimilated separately into the VAFES forecasts forced with solar heating that excludes the diurnal component Qz; one was created from a VAFES run forced with solar heating that includes the diurnal component Qt, whereas the other was based on observations made by the Venus Monitoring Camera (VMC) onboard the Venus Express. The VAFES-LETKF system rapidly reduced the errors between the analysis and forecasts. In addition, the VAFES-LETKF system successfully reproduced the thermal tide excited by the diurnal component of solar heating, even though the second datasets only included horizontal winds at a single altitude on the dayside with a long interval of approximately one Earth day. This advanced system could be useful in the analysis of future datasets from the Venus Climate Orbiter 'Akatsuki'.
金星的大小和质量与地球相似；然而，由于观测和计算困难，其大气动力学有很大的不同，目前还不太了解。在这里，我们为地球模拟器上的金星大气通用环流模型（VAFES）开发了一个基于局地集合变换卡尔曼滤波（LETKF）的数据同化系统，以充分利用观测数据。为了检验系统的有效性，我们分别将两个数据集同化到 VAFES 预测中，这些预测由不包括日分量 Qz 的太阳加热强迫，一个数据集是由一个包括日分量 Qt 的太阳加热强迫的 VAFES 运行创建的，而另一个数据集则基于金星快车上的金星监测相机（VMC）的观测结果。VAFES-LETKF 系统迅速减少了分析和预测之间的误差。此外，VAFES-LETKF 系统成功地再现了由太阳加热日分量激发的热潮汐，尽管第二个数据集只包括了白天单个高度的水平风，而且大约有一个地球日的长间隔。这个先进的系统在分析未来来自金星气候轨道飞行器“黎明”的数据集中可能会很有用。
