Characteristics of Cloud Water Resource and Precipitation Efficiency of Hydrometeors over Northwest China

Understanding the characteristics of cloud water resource (CWR) and precipitation efficiency of hydrometeors (PE_h) is imperative for the application of CWR in Northwest China. The atmospheric precipitable water (PW) in all four seasons and clouds and PE_h in summer were studied with ERA-5 and CloudSat data in this region. The results show that topography, especially in the Tibetan Plateau, exerts significant impacts on the precipitation and PW in summer, since large amounts of clouds are distributed along the mountain ranges. The study region is divided into four typical areas: the monsoon area in eastern Northwest China (NWE), the Qilian Mountains area (QM), the Tianshan Mountains area (TM), and the Source of Three Rivers area (STR). Over the four areas, cloud top height (6.3 km) and cloud base height (3.3 km) over NWE are higher, and precipitating clouds are thicker (7 km) in the single-layer clouds. Liquid water content decreases with increasing altitude, while the ice water content first increases and then decreases. Liquid water path is higher over NWE (0.11 kg m⁻²) than over TM and STR (0.05 kg m⁻²), and the ice water path is mainly concentrated within the range of 0.025–0.055 kg m⁻². The PE_h values are distributed unevenly and affected evidently by the terrain. Although the PE_h values in the four typical areas (0.3–0.6) are higher than those in other regions, the CWR is relatively abundant and has a higher exploitation potential. Therefore, it is well-founded to exploit CWR for alleviating water shortages in these areas of Northwest China in summer.