SAMI3 data in netCDF format (2019-May-05)

SAMI3 (Sami3 is Also a Model of the Ionosphere) is a seamless, three-dimensional, physics-based model of the ionosphere (Huba et al, 2008). It is based on SAMI2, a two-dimensional model of the ionosphere (Huba et al., 2000). <br><br>SAMI3 models the plasma and chemical evolution of seven ion species (H⁺, He⁺, N⁺, O⁺, N⁺₂, NO⁺ and O⁺₂). The temperature equation is solved for three ion species (H⁺, He⁺ and O⁺) and for the electrons. Ion inertia is included in the ion momentum equation for motion along the geomagnetic field. This is important in modeling the topside ionosphere and plasmasphere where the plasma becomes collisionless. <br><br>SAMI3 includes 21 chemical reactions and radiative recombination, and uses a nonorthogonal, nonuniform, fixed grid for the magnetic latitude range +/- 89 degrees.. <br><br><b>Drivers</b><br>Neutral composition, temperature, and winds: NRLMSISE00 (Picone et al., 2002) and HWM14 (Drob et al., 2015). <br>Solar radiation: Flare Irradiance Spectral Model version 2 (FISM v2)<br>Magnetic field: Richmond apex model [Richmond, 1995]. <br>Neutral wind dynamo electric field: Determined from the solution of a 2D potential equation [Huba et at., 2008]. <br>For the SAMI3/Weimer configuration: High latitude electric field: calculated from the empirical Weimer model for the potential. <br>For the SAMI3/AMPERE configuration: High latitude electric field: calculated using the Magnetosphere-Ionosphere Coupling solver (MIX) developed by Merkin and Lyon (2010). The inputs to MIX are SAMI3's internal conductances, plus field-aligned current observations from Active Magnetosphere and Planetary Electrodynamics Response Experiment (AMPERE), derived from the 66+ satellite Iridium NEXT constellation's engineering magnetometer data. This potential calculation is described in Chartier et al (2022). <br><br>For ease of use, SAMI3 output is remapped to a regular grid using the Earth System Modeling Framework by Hill et al (2004)SAMI3（全称Sami3 is Also a Model of the Ionosphere，即电离层模型）是一款无缝衔接的三维物理基电离层模型（Huba等，2008）。该模型基于此前的二维电离层模型SAMI2（Huba等，2000）。 SAMI3可模拟7种离子组分（H⁺、He⁺、N⁺、O⁺、N₂⁺、NO⁺及O₂⁺）的等离子体与化学演化过程。针对H⁺、He⁺与O⁺三种离子以及电子，模型求解了温度方程；同时在沿地磁场运动的离子动量方程中纳入了离子惯性项，这对无碰撞等离子体所在的顶部电离层与等离子体层的模拟至关重要。 SAMI3包含21种化学反应与辐射复合过程，并针对磁纬度范围±89°采用了非正交、非均匀的固定网格。 ### 驱动源 中性成分、温度与风场：采用NRLMSISE00模型（Picone等，2002）与HWM14模型（Drob等，2015）。 太阳辐射：采用耀斑辐照度光谱模型第2版（Flare Irradiance Spectral Model version 2，FISM v2）。 地磁场：采用Richmond顶点模型（Richmond，1995）。 中性风发电机电场：通过二维势方程的求解结果确定（Huba等，2008）。 针对SAMI3/Weimer配置： 高纬度电场由用于电势计算的经验Weimer模型推导得到。 针对SAMI3/AMPERE配置： 高纬度电场通过Merkin与Lyon（2010）开发的磁层-电离层耦合求解器（Magnetosphere-Ionosphere Coupling solver，MIX）计算得到。MIX的输入参数包含SAMI3的内部电导率，以及源自66颗及以上铱星Next（Iridium NEXT）星座工程磁强计数据的有源磁层与行星电动力学响应实验（Active Magnetosphere and Planetary Electrodynamics Response Experiment，AMPERE）的场向电流观测值。该电势计算方法由Chartier等（2022）详细阐述。 为便于使用，Hill等（2004）通过地球系统建模框架（Earth System Modeling Framework，ESMF）将SAMI3的输出结果重映射至规则网格。