Browsing by Author "He, M."
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Item Restricted Can a nightside geomagnetic Delta H observed at the equator manifest a penetration electric field?(American Geophysical Union, 2013-02-12) Wei, Y.; Fraenz, M.; Dubinin, E.; He, M.; Ren, Z.; Zhao, B.; Liu, J.; Wan, W.; Yumoto, K.; Watari, S.; Alex, S.A prompt penetration electric field (PPEF) usually manifests itself in the form of an equatorial ionospheric electric field being in correlation with a solar wind electric field. Due to the strong Cowling conductivity, a PPEF on the dayside can be inferred from Delta H (ΔH), which is the difference in the magnitudes of the horizontal (H) component between a magnetometer at the magnetic equator and one off the equator. This paper aims to investigate the performance of ΔH in response to a PPEF on the nightside, where the Cowling conductivity is not significant. We first examine the strongest geomagnetically active time during the 20 November 2003 superstorm when the Dst drops to −473 nT and show that the nightside ΔH can indeed manifest a PPEF but with local time dependence and longitude dependence. We then examine a moderately active time by taking advantage of the multiple‐penetration event during 11–16 November 2003 when the Dst remains greater than −60 nT. During this event, a series of PPEF pulses recorded in Peru, Japan, and India form a database, allowing us to examine PPEF effects at different local times and longitudes. The results show that (1) the nightside ΔH was caused by attenuation of the effects of the polar electric field with decreasing latitude; (2) the nightside ΔH can manifest a PPEF at least in the midnight‐dawn sector (0000–0500 LT), but not always; and (3) the magnitude of the nightside ΔH in the midnight‐dawn sector in Peru is on average only 1/18 of that of the dayside ΔH in response to a given PPEF.Item Open Access Diurnal and semidiurnal tides in the Mesosphere and Lower Thermosphere over the central coast of Peru(Instituto Geofísico del Perú, 2021-06) Suclupe, J.; Milla, Marco; He, M.; Chau, J. L.It has been over a year since measurements of mesosphere and lower thermosphere (MLT) winds have been obtained with the SIMONe Peru radar. This modern multistatic specular meteor radar, placed on the central coast of Peru, has its transmitter located at the Jicamarca Radio Observatory (11.95° S, 76.87° W, dip angle 1°). This work will show some results of the climatology of diurnal and semidiurnal tides obtained from the analysis of zonal and meridional mean winds that have been estimated at heights between 80-100 km using one year of data (Nov 2019 - Oct 2020). The monthly and seasonal variation of tide amplitudes will be described. From the results we have seen that diurnal tides are more intense than semidiurnal tides, which is typical at low latitudes and that diurnal tide is more intense in August and September. These and others results will also be described in this work.