**4. Discussion**

In theory, there are multi-scale atmospheric motions, especially over the complex TP regions, which interact with each other. The local land-atmosphere heat transfers over TP could be possibly affected by the large-scale circulations, such as the surrounding South Asia monsoon systems. Theoretically, the monsoon could affect the local heat transfer by adjusting the local radiation conditions through cloud and precipitation variations, which have been proved by previous studies [9,23,27].

From our results, not all stations show consistent impacts from SASM. For example, the Biru station has an opposite variation of heat flux during the different SASM stages, compared with other stations at similar latitudes, such as Baingoin and Lhari. The reason is still unclear; this may have connections with orographic peculiarities and microclimatic features, and which could be partly leading to the different local heating forces there. The problem also needs to be further studied using longer-time observation data in the future.

The spatial differences between various sites could be possibly not only affected by the SASM activities. Our study presented a clue that the local land-air exchange processes could be strongly affected by large-scale circulations, such as the SASM evolution, with inhomogeneous distributions over the whole TP region. The local topographic effects should be carefully considered for future studies.

Due to the hard living and working conditions, the observational data are quite limited over Tibet, especially over the northern and western parts of the plateau. Thus, as shown in our introduction, most previous studies focused mainly on the SASM impacts over the south or the southeast Tibet, one reason is due to the largest impacts there which were shown from our studies, and another reason is no observational data over the other plateau regions. During the most recent year, the Third Tibetan Plateau Atmospheric Scientific Experiment provided us with an opportunity to make a comprehensive study on the possible SASM impacts on different regions of TP. Although our conclusions are based on only one year of data (2014), the physical mechanism is the same for the other year, in spite of year-to-year variations. The SASM evolution could result in cloud and advection variations, adjusting the local radiation conditions, and further affecting the local heat transfers. Therefore, the inhomogeneities of SASM impacts should be confirmed for each year, but varied with different amplitudes and monsoon extended regions. In the future, based on more accumulated data, further investigations and more evidence are still needed for the robustness of conclusions.
