Abstract. In this study, we analyze the climatology of ionosphere over Nepal based on GPS derived VTEC observed from four stations: KKN4 (27.80° N, 85.27° E), GRHI (27.95° N, 82.49° E), JMSM (28.80° N, 83.74° E), DLPA (28.98° N,82.81° E) during years 2008 to 2018. The study illustrates the diurnal, monthly, annual, seasonal and solar cycle variations of VTEC during all time of solar cycle 24. The results clearly revel the presence of equinoctial asymmetry in TEC which is more pronounced in maximum phases of solar cycle in year 2014 at KKN4 station followed by descending, ascending and minimum phases. Diurnal variation of VTEC showed short-lived day minimum which occurs between 5:00 to 6:00 LT at all the stations considered with diurnal peak between around 12:00 to 15:00 LT. The maximum value of TEC is observed during spring equinox than autumn equinox with a few anomalies. Similarly, winter anomalies are noticed during increasing and maximum phases of the solar cycle2011 and 2014 from almost all stations taken in the study.

中文翻译：

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基于2008年至2018年GPS TEC数据的尼泊尔电离层气候

摘要。在这项研究中，我们基于从四个站点观测到的GPS衍生的VTEC分析了尼泊尔上方的电离层气候：KKN4（北纬27.80°，东经85.27°），GRHI（北纬27.95°，北纬82.49°），JMSM（北纬28.80°， 83.74°E），DLPA（28.98°N，82.81°E）在2008年至2018年期间。研究表明，VTEC在太阳活动周期24的所有时间中的日，月，年，季节和太阳活动周期变化。 TEC中存在等时不对称，这在KKN4站2014年太阳周期的最大阶段尤为明显，其后依次是下降，上升和最小阶段。VTEC的昼夜变化显示了短时的最小天数，该时间发生在所有LT的5:00到6:00 LT之间，并且所有LT的昼夜峰值在LT的12:00到15:00左右。在春季春分期间比秋季春分期间观察到TEC的最大值，但有一些异常。同样，研究中几乎所有台站在2011年和2014年太阳周期的增加阶段和最大阶段都注意到冬季异常。