## 3 Results
### TLT Trend  
It is observed that the lower tropospheric (0-3 km) temperature over the dust source (Afghan-Pak, Iran-Pak, Middle East, Arabian region, North African region) and dust sink regions (IG west, IG east) exhibits a general trend of warming (Table 7). Over a period of 45 years, there has been an average temperature increase of 1.01 \({}^{\circ}\)K in the dust source and sink regions. Specifically, the IG east region has experienced an annual mean trend of 0.70 \({}^{\circ}\)K (0.155 \(\pm\) 0.029 \({}^{\circ}\)K/decade) between 1978 and 2022 (Table 7). This warming trend is more pronounced during six specific months, namely March, April, and May, and August, September, and October (Table 8, Figure 6). In the IG west, the pre-monsoon, monsoon, and winter months (June to January, except August) show a relatively negative TLT anomaly (Table 9, Figure 6). The important features are: \begin{table}
\begin{tabular}{c c c c c c c c c c c c} \hline \hline
**Area Code** & **Area Name** & **Anom.** & **Anom.** & **Trend** & **Trend SE** & **Trend** & **Trend SE** & **Change \({}^{\circ}\)K** & **Trend Is** \\  & **(avg) in \({}^{\circ}\)K** & **in \({}^{\circ}\)K** & **(\({}^{\circ}\)K/year)** & **(\({}^{\circ}\)K/year)** & **(\({}^{\circ}\)K/decade)** & **(\({}^{\circ}\)K/decade)** & **(\({}^{\circ}\)K/decade)** & **(\({}^{\circ}\)K/decade)** & **(\({}^{\circ}\)K/decade)** & **(\({}^{\circ}\)K/decade)** \\ \hline A & Tibet & - & - & - & - & - & - & - & - & - \\ B & Himalaya W. & - & - & - & - & - & - & - & - & - \\ C & Himalaya E. & - & - & - & - & - & - & - & - & - \\ D & IG West & 0.030 & 0.094 & 0.005 & 0.004 & 0.048 & 0.036 & 0.21 & No \\ E & IG East & 0.201 & 0.062 & 0.015 & 0.003 & 0.155 & 0.029 & 0.70 & Yes \\ \hline \hline \end{tabular}
\end{table} 
Table 7: For lower troposphere temperature (TLT), the overall average anomaly (\({}^{\circ}\)K), trend, standard error (SE, \({}^{\circ}\)K/year), and total change (\({}^{\circ}\)K) as computed from the Microwave Sounding Unit/Advanced Microwave Sounding Unit (MSU/AMSU) data (1978–2022). \begin{table}
\begin{tabular}{c c c c c c c c c c c c c c} \hline \hline
**Area** & **Trend** & **Jan** & **Feb** & **Mar** & **Apr** & **May** & **Jun** & **Jul** & **Aug** & **Sep** & **Oct** & **Nov** & **Dec** \\ \hline Tibet & Slope & - & - & - & - & - & - & - & - & - & - & - & - \\  & SE & - & - & - & - & - & - & - & - & - & - & - & - \\ \hline Himalaya W & Slope & - & - & - & - & - & - & - & - & - & - & - & - \\  & SE & - & - & - & - & - & - & - &  
During the period of March to June, the Indo-Gangetic Plain (IGP) is significantly influenced by locally produced and transported dust, primarily originating from dust source regions in western Asia, the Thar desert, and adjacent arid agriculture lands [84,85]. In general, the positive TLT anomaly during these months (Table 9) indicates the influence of the dust storm season. Although June exhibits higher aerosol concentrations, it is also a month characterized by a contrasting transition in the mid-troposphere temperature between the dust source and sink regions. This suggests that factors other than aerosols play a role in modulating the observed warming trends. * The monthly breakup of the TLT trend of IG east (Table 8) shows an increase in warming trends during pre-monsoon months (MAM) ranging from 0.020 \(\pm\) 0.011 \({}^{\circ}\)K/year to 0.031 \(\pm\) 0.008 \({}^{\circ}\)K/year. * The monthly TLT trends of IG west show an increase in warming trends from April to June, ranging from 0.014 \(\pm\) 0.006 \({}^{\circ}\)K/year to 0.016 \(\pm\) 0.005 \({}^{\circ}\)K/year. This can be attributed to the early arrival of the SW monsoon in the eastern Gangetic plains (first week of June) compared to the western Gangetic plains (last week of June), where the SW monsoon progresses rapidly from east to west during the month of June.