Abstract. Mesopause is the zone of minimum temperature in Earth’s atmosphere. Temperature variation in this region is one of the important responsible factors for chemical and physical changes including spatiotemporal variability in water vapor content. Twenty-two years of monthly temperature and water vapor data were used from Sounding of the Atmosphere using Broadband Emission Radiometry. Eight months per year (excluding transitional months) were selected for temporal analysis. Spatially the region is classified into four parts including Northern, and Southern Poles. Long-term variations in water vapor and temperature in the selected domains of time and space as well as at equinoxes and solstices are presented. A decreasing, and increasing trend in temperature and water vapor respectively was observed during the study period. Yearly averaged temperature and water vapor content showed that 2002 was the hottest year (193 K) and had minimum water vaper content (0.89 ppmv) and 2018 was the coldest year (187 K) and had maximum water vapor content (1.14 ppmv). June and July were the coldest months and January and December were hotter months throughout the year over the North Pole and Equator. The vertical gradient of temperature and water vapor (80 to 100 km) changes with space and time however, has a strong negative relation in all selected locations and seasons. Around the equinoxes, the monthly average distribution of mesopause temperature was highest (191 K), followed by winter solstice and then summer solstice. The decreasing trend in temperature and an increasing trend in water vapor can be an early warning indication for future climate change.

中文翻译：

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中层顶区域长期气温和水汽的时空变化

摘要。中层顶是地球大气中温度最低的区域。该地区的温度变化是化学和物理变化（包括水蒸气含量的时空变化）的重要影响因素之一。使用宽带发射辐射测量法探测大气层中使用了二十二年的每月温度和水蒸气数据。每年选择八个月（不包括过渡月份）进行时间分析。该地区在空间上分为四个部分，包括北极和南极。呈现了选定的时间和空间范围以及春分和至日的水蒸气和温度的长期变化。在研究期间，观察到温度和水蒸气分别呈下降和上升趋势。年平均气温和水汽含量显示，2002年为最热年份（193 K），水汽含量最低（0.89 ppmv）；2018年为最冷年份（187 K），水汽含量最高（1.14 ppmv）。北极和赤道全年最冷的月份是 6 月和 7 月，1 月和 12 月是最热的月份。温度和水汽的垂直梯度（80至100公里）随着空间和时间的变化而变化，然而，在所有选定的地点和季节中都具有很强的负相关关系。春分前后，中层顶温度的月平均分布最高（191 K），其次是冬至，然后是夏至。温度的下降趋势和水蒸气的增加趋势可以作为未来气候变化的预警信号。