The interpretation of gas adsorption behavior on a coal surface is an important theoretical basis for gas injection to enhance the recovery of coalbed methane. In order to further explore the adsorption properties of different gases (CH 4 /CO 2 /N 2 ) on the coal surface, the thermodynamic parameters of adsorption were revealed using a molecular simulation method. The results show that the Langmuir−Freundlich model is more accurate to represent gas adsorption on anthracite coal than the Langmuir model and Freundlich model, which reveal that the gas adsorption on the coal surface is heterogeneous. Also, thermodynamic parameters indicate that gas adsorption on anthracite coal is a thermodynamically spontaneous (ΔG < 0) and exothermic physisorption (0 < ΔH < 10 kcal/mol) process, and the gas molecules tend to be in an ordered state (ΔS > 0). According to adsorption affinity and thermodynamic parameters, the adsorption capacity of these three gases on a coal surface follows the sequence of CO 2 > CH 4 > N 2 . This research can provide foundational knowledge for further interpretation of gas adsorption behavior on a coal surface.

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This study aims to evaluate the performances of two latest released GPM-era satellite precipitation final run products (IMERG-V06B and GSMaP-V07) and one TRMM-era product (TMPA-3B42-V07) at hourly, daily and monthly scale over the TP, with special focus on the performances at different rain intensities, sub-basins, and elevations at daily scales. Besides, hourly scale evaluations were carried out for one grid box value of IMERG-V06B and GSMaP-V07 versus 15 rain gauges on the rainy season, 2019. Results indicated that (1) GSMaP-V07 outperformed TMPA-3B42-V07 and IMERG-V06B with higher CC and lower RBias, MAE, and RMSE values at daily and monthly scale. (2) Satellite products showed overestimation during light rain and underestimation throughout moderate rain, heavy rain and rainstorm; (3) Satellite products have performed relatively better in lower elevation (<3000 m) regions, but they greatly overestimated the precipitation (more than 50%) at high-elevation (>4000 m). (4) Satellite precipitation products performed better in the source region of the Yellow River (SRYR), Yangtze Rivers (SRYZR), Lancang River (SRLCR), and Nujiang River (SRNR) basins, while the products greatly overestimated the precipitation in the source region of the Yarlung zangbo River (SRYLZB) basin. In arid climate regions (Qiangtang Basin and Qaidam Basin), GSMaP-V07 had better performances than other products; (5) Although GSMaP-V07 showed higher overestimation than IMERG-V06B product at hourly scale, it has better consistency with rain-gauge observations. For satellite precipitation data application within the TP, we recommend the GSMaP-V07 over the IMERG-V06B. Furthermore, improvement on the multi-satellite rainfall retrieval algorithm is required. Index terms -Tibetan Plateau(TP), Satellite precipitation products, TMPA, GSMaP, IMERG

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