## 5 Summary and Conclusions  
By using the COSMIC-2 RO dry temperature profiles from December 2019 to November 2021, the GW Ep profiles in the LS of the Indian region (60\({}^{\circ}\)E-100\({}^{\circ}\)E, 0\({}^{\circ}\)-30\({}^{\circ}\)N) are derived, based on which the seasonal variation of the LS GWs in the height range of 20-30 km (abbreviated as the LS GWs) is presented, and the correlations between the mean LS GW Ep and nine influencing factors are analyzed. The influence of each factor is further quantified using the DA method, which outperforms correlation analysis in evaluating the individual contribution of each factor when collinearity exists in the influencing factors. The LS GWs in the Indian region show distinct annual variations, and the maxima of the mean LS GW Ep appears in JJA. Generally, the TEJ, which prevails over the Indian region during JJA, and the Indian summer monsoon, which enhances the local convection activity, both bring favorable conditions for the generation and propagation of GWs. The correlation analysis reveals that in the Indian region, most of the selected factors have a strong correlation with LS GW, indicating that the selected factors have an undeniable impact on LS GW activity, at least in certain parts of the Indian region. If there are strong correlations between LS GW activity and multiple factors in a specific area, it is difficult to quantify the relative influence of these factors based on CCs only. The distributions of the RICs obtained with the DA method demonstrate that the factors that are of great relative importance on the LS GWs vary in different geographic areas of the Indian region. Specifically, in the central and the northern parts of the Indian region, especially in the southern foothills of the Himalayas, the contribution of convection activity is the greatest, which should be due to the interaction of the Indian summer monsoon circulation and the terrain of the Himalayas in summer. The mean zonal wind speed between 15 and 17 km  
Figure 7: The time–longitude distribution of the mean GW Ep value between 20 and 21 km at 10\({}^{\circ}\)N in the Indian Region. is the factor with the second greatest relative importance, indicating that the TEJ, which prevails over the Indian region during JJA, is an important source for the LS GWs. The mean zonal wind speed between 20 and 30 km also has a non-negligible influence. In the southern part of the Indian Peninsula and over the Indian Ocean, the mean zonal wind shear between 20 and 30 km is the dominant factor influencing the LS GWs. The dominance analysis also reveals that the influences of the zonal wind speeds and the zonal wind shears on the LS GWs are different over different local areas of the Indian region. The sums of the RICs of all the nine considered factors are generally higher than 0.7, which may demonstrate that in most parts of the Indian region, the TEJ with the core in the height range of 15-17 km, the air flows between 20 and 30 km, and the convections that are closely related to the Indian summer monsoon are actually the main factors affecting the LS GWs. Further analysis of the impacts of zonal wind speeds and wind shears on the LS GWs in different local regions showed that, in the southern part of the Indian Peninsula and over the Indian Ocean, strong westward wind shear generated over 20 km may have a filtering effect on gravity waves propagated from below, making it difficult for GWs to propagate to above 23 km during the 2021 JJA. Therefore, wind shear becomes the dominant factor in the GW activity in this region. In the central and northern parts of the Indian region, due to the absence of strong wind shear, gravity wave energy propagated upwards to 30 km during the JJA of 2020 and 2021. The RIC values of the mean zonal wind speed between 15 and 17 km, which represents the wave source of TEJ, and the mean zonal wind speed between 20-30 km, which represents the propagation conditions, become higher.