Observations of the May 30, 1984, annular solar eclipse at Millstone Hill
Observations of the May 30, 1984, annular solar eclipse at Millstone Hill
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DOI：
10.1029/ja091ia02p01651
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发表时间：
1986-02
影响因子：
--
通讯作者：
J. Salah;W. Oliver;J. Foster;J. Holt;B. Emery;R. Roble
中科院分区：
文献类型：
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作者：
J. Salah;W. Oliver;J. Foster;J. Holt;B. Emery;R. Roble
Millstone Hill非相干散射雷达于1984年5月30日运行，收集日环食对地球电离层和热层结构和动力学影响的数据。在1700 UT，Millstone Hill经历了86%的最大遮蔽，并且只有低磁活动与事件一致。在米尔斯通山使用天顶固定天线和可操纵天线进行的观测表明，在130-250公里高度区域，电子密度在峰值遮蔽时间后不久下降了60%，在更高的高度下降幅度较小（15-30%）。电子温度被发现降低了500-700 K在F区在日食期间，和相对较小的变化被观察到的离子或中性温度。在F区测得的三维离子漂移是根据日食时向北约25 m/s的纬向风速合成的，这代表着日食前的条件下降了40-50 m/s。电场强度小于1 mV/m，并显示出与Millstone Hill安静时间场相同的一般模式。与NCAR热层大气环流模型对这次日食的中性大气响应预测和NCAR电离层模型对电离层响应预测的比较表明，250公里以下的电子密度和温度吻合得很好;在更高的高度上，当考虑到边界层的热通量和电离通量的影响时，预测和观测结果就可以相互协调电离层模型中的条件。预测的中性风在测量值的2倍之内，但很难从数据中可靠地确定会聚到日食路径上的扰动场的大小。
The Millstone Hill incoherent scatter radar was operated on May 30, 1984, to gather data on the effects of the annular solar eclipse on the structure and dynamics of the earth's ionosphere and thermosphere. Maximum obscuration of 86% was experienced at Millstone Hill at 1700 UT, and there was only low magnetic activity coincident with the event. The observations, which were made using both the zenith-fixed and the steerable antenna at Millstone Hill, indicated a drop of 60% in electron density shortly after peak obscuration time in the altitude region 130–250 km and a smaller decrease (15–30%) at higher altitudes. The electron temperature was found to decrease by 500–700 K in the F region during the eclipse, and relatively little variation was observed in the ion or neutral temperature. The measured three-dimensional ion drifts in the F region were synthesized in terms of a meridional wind velocity of about 25 m/s northward at eclipse time, which represents a drop of 40–50 m/s from conditions prior to the eclipse. Electric field strengths were less than 1 mV/m and showed the same general pattern as quiet time fields at Millstone Hill. Comparisons with predictions of the neutral atmospheric response made for this eclipse by the NCAR thermospheric general circulation model (TGCM) and of the ionospheric response made by the NCAR ionospheric model indicate good agreement below 250 km for the electron density and temperature; at higher altitudes the predictions and observations can be reconciled when the effects of heat and ionization flux are taken into account for the boundary condition in the ionospheric model. The predicted neutral winds are within a factor of 2 of the measurements, but it is difficult to ascertain reliably from the data the magnitude of the perturbation fields converging onto the eclipse path.