Three static stability indices (K-index, KI; Lifted-index, LI; and Total Totals index, TTI) and three related thermodynamic parameters (First and second Adedokun indices; ADED1 and ADED2 as well as the available potential energy; CAPE) were estimated to predict instability condition and precipitation over Nigeria. ERA5 reanalysis datasets of daily air temperature and specific humidity at multiple pressure levels from 1979 to 2018 were used for the prediction while the computed seasonal averages of the static stability indices (SSIs) and thermodynamic parameters (TPs) were validated with the precipitation data. It was revealed that SSIs and TPs produced ranges of values that were fairly good predictive of atmospheric convection and instability conditions over different climatic zones. They adequately captured seasonal variations in atmospheric instability conditions and migration and pulsation of the south-westerly and the north-easterly wind systems. Significant decreasing trends in annual SSIs, PTs, and precipitation were obtained over Sahel. Furthermore, fairly strong and significant positive correlations (0.66 ≤ r ≤ 0.87) were obtained between precipitation and SSIs in the north i.e. Sahel and Savannah. Fluctuation in precipitation was explained by 26–70% variations in LI, 13–19% in ADED1, and 27–36% variations in KI, particularly in the north. In conclusion, diminishing trends of the LI, KI, and ADED1 during the 40-year study period were adduced to reduced precipitation. The study has application in improved weather forecast of convection systems and precipitation in West Africa at large.

中文翻译：

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评估用于预测尼日利亚大气对流势和降水的静态稳定性指数和相关热力学参数

三个静态稳定性指数（K 指数，KI；提升指数，LI；和总指数，TTI）和三个相关的热力学参数（第一和第二 Adedokun 指数；ADED1 和 ADED2 以及可用势能；CAPE）是估计预测尼日利亚的不稳定状况和降水。1979 年至 2018 年多个压力水平下的 ERA5 日气温和比湿度再分析数据集被用于预测，而静态稳定性指数 (SSI) 和热力学参数 (TP) 的计算季节性平均值则通过降水数据进行验证。结果表明，SSI 和 TP 产生的值范围可以很好地预测不同气候带上的大气对流和不稳定条件。他们充分捕捉到了大气不稳定条件的季节性变化以及西南风和东北风系统的迁移和脉动。在萨赫勒上空获得了年度 SSI、PT 和降水的显着下降趋势。此外，在北部（即萨赫勒和萨凡纳）降水与 SSI 之间获得了相当强且显着的正相关（0.66 ≤ r ≤ 0.87）。降水量的波动可以通过 LI 的 26-70% 变化、ADED1 的 13-19% 和 KI 的 27-36% 变化来解释，特别是在北部。总之，在 40 年的研究期间，LI、KI 和 ADED1 的减少趋势被归因于降水减少。该研究已应用于改进西非对流系统和降水的天气预报。