The equatorial and low-latitude ionosphere within the context of global modeling

The thermosphere–ionosphere–mesosphere-electrodynamics coupled model TIME-GCM, coupled to NCEP lower atmosphere data, is used to simulate the noontime ionospheric peak electron density NmF2 at low latitudes for year 2002. Model output are compared with observations a three ionosonde stations: Jicamarca, Ascension Island and Darwin, stations at geomagnetic latitudes of 3°S, 10°S and 22°S, respectively. The modeled electron density at the peak of the F2-layer (NmF2) matches the general trend of the data fairly well at noon throughout the year. The shapes of the diurnal curves of NmF2 vs. local time are not well produced in the model, and particularly so at the two stations away from the geomagnetic equator. At all sites the day-to-day variability of NmF2, assessed using the percent standard deviation about the monthly mean, is about twice the modeled variability. Possible sources of this shortfall in the model may be due to the under-representation of coupling from below and/or from auroral sources.

热层 - 电离层 - 中间层 - 电动力学耦合模式（TIME - GCM）与美国国家环境预报中心（NCEP）的低层大气数据相耦合，用于模拟2002年低纬度地区中午电离层峰值电子密度NmF2。将模式输出结果与三个电离层探测站的观测数据进行了比较，这三个站分别是：地磁纬度为南纬3°的伊卡马尔卡站、南纬10°的阿森松岛站和南纬22°的达尔文站。F2层峰值处的模拟电子密度（NmF2）与全年中午的数据总体趋势相当吻合。NmF2随地方时变化的日曲线形状在模式中没有很好地呈现出来，在地磁赤道以外的两个站尤其如此。在所有站点，使用相对于月均值的百分比标准偏差评估的NmF2逐日变化约为模拟变化的两倍。模式中这种不足的可能原因可能是由于来自下方和/或极光源的耦合体现不足。