Tracking moisture sources of precipitation over Central Asia: A study based on the water-source-tagging method

Journal Article · Tue Dec 01 04:00:00 EST 2020 · Journal of Climate

DOI:https://doi.org/10.1175/JCLI-D-20-0169.1· OSTI ID:1734556

Jiang, Jie ^[1]; Zhou, Tianjun ^[2]; Wang, Hailong ^[3]; Qian, Yun ^[3]; Noone, David C. ^[4]; Man, Wenmin ^[2]

---

1. Institute of Atmospheric Physics, Chinese Academy of Sciences
2. Chinese Academy of Sciences
3. BATTELLE (PACIFIC NW LAB)
4. OREGON STATE UNIVERSITY

Central Asia is a semi-arid to arid region that is sensitive to hydrological changes. We use the Community Atmosphere Model version 5 (CAM5), equipped with a water tagging capability, to investigate the major moisture sources for climatological precipitation and its long-term trends over Central Asia. Europe, the north Atlantic and local evaporation, which explain 33.2±1.5%, 23.0±2.5% and 19.4±2.2% of the precipitation, respectively, are identified as the most dominant moisture sources for northern Central Asia (NCA). For precipitation over southern Central Asia (SCA), Europe, the north Atlantic and local evaporation contributes 25.4±2.7%, 18.0±1.7% and 14.7±1.9%, respectively. In addition, the contributions of South Asia (8.6±1.7%) and Indian Ocean (9.5±2.0%) are also substantial for SCA. Modulated by the seasonal meridional shift of subtropical westerly jet, moisture originating from low- and mid-latitude is important in winter, spring and autumn, while northern Europe contributes more in summer. We also explain the observed drying trends over southeastern Central Asia in spring and over NCA in summer during 1956-2005. The drying trend over the southeastern Central Asia in spring is mainly due to the decrease of local evaporation and weakened moisture fluxes from the Arabian Peninsula and Arabian Sea associated with the warming Western Pacific. The drying trend over NCA in summer can be attributed to the decrease of local evaporation and reduced moisture from northern Europe due to the southward shift of the subtropical westerly jet.

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 1734556
• Report Number(s): PNNL-SA-154140
• Journal Information: Journal of Climate, Journal Name: Journal of Climate Journal Issue: 23 Vol. 33
• Country of Publication: United States
• Language: English