Moisture Transport and Precipitation Mechanisms in the Eastern Pamir during Monsoon Season

The Eastern Pamir Plateau (EPA) receives most of its precipitation during its monsoon season. Although Central Asia is projected to experience a wetter climate under global warming, moisture transport mechanisms to the eastern Pamir remain unclear. Using ERA5, Cloud Archive User Service (CLAUS), and IMERG datasets, this study examines moisture transport characteristics and underlying mechanisms for both convective and non-convective precipitation events over the EPA. Results indicate that the Hindu Kush–northwestern Himalayas corridor serves as a key moisture pathway. Anomalous shallow troughs or low-pressure systems near and above the EPA directly promote upward motion and precipitation. However, these processes are ultimately governed by the thermodynamic and dynamic interplay between mid-to-upper-level warming induced by the Indian Summer Monsoon (ISM) and colder air from higher latitudes. Three distinct regimes are identified: (1) strong ISM dominance during convective precipitation over northern Pakistan; (2) a moderate ISM combined with Tibetan Plateau Monsoon (TPM) influence when convection occurs along the western and eastern EPA margins; (3) a very weak ISM during non-convective heavy precipitation. While both an intensified ISM and TPM favor increased EPA rainfall, neither alone suffices to produce significant precipitation. Importantly, the ISM primarily shapes the upper-level circulation over the Tibetan Plateau, whereas the TPM acts as a secondary modulator.