On the Mechanisms of a Snowstorm Associated with a Low-Level Cold Front and Low-Level Jet in the Western Mountainous Region of the Junggar Basin, Xinjiang, Northwest China
Xiaoning He,
Abuduwaili Abulikemu,
Ali Mamtimin,
Ruqi Li,
Aerzuna Abulimiti,
Dawei An,
Mangsuer Aireti,
Yaman Zhou,
Qi Sun,
Zhiyi Li,
Lin Yuan,
Tao Xi
Affiliations
Xiaoning He
Xinjiang Key Laboratory of Oasis Ecology, College of Geography and Remote Sensing Sciences, Xinjiang University, Urumqi 830017, China
Abuduwaili Abulikemu
Xinjiang Key Laboratory of Oasis Ecology, College of Geography and Remote Sensing Sciences, Xinjiang University, Urumqi 830017, China
Ali Mamtimin
Institute of Desert Meteorology, CMA, Urumqi 830002, China
Ruqi Li
Xinjiang Meteorological Observatory, Urumqi 830002, China
Aerzuna Abulimiti
Xinjiang Key Laboratory of Oasis Ecology, College of Geography and Remote Sensing Sciences, Xinjiang University, Urumqi 830017, China
Dawei An
Xinjiang Meteorological Observatory, Urumqi 830002, China
Mangsuer Aireti
Xinjiang Meteorological Observatory, Urumqi 830002, China
Yaman Zhou
Xinjiang Meteorological Observatory, Urumqi 830002, China
Qi Sun
Xinjiang Key Laboratory of Oasis Ecology, College of Geography and Remote Sensing Sciences, Xinjiang University, Urumqi 830017, China
Zhiyi Li
Xinjiang Key Laboratory of Oasis Ecology, College of Geography and Remote Sensing Sciences, Xinjiang University, Urumqi 830017, China
Lin Yuan
Xinjiang Key Laboratory of Oasis Ecology, College of Geography and Remote Sensing Sciences, Xinjiang University, Urumqi 830017, China
Tao Xi
Liaoning Provincial Meteorological Service Center, Shenyang 110166, China
Snowstorms frequently hit large parts of the Northern Hemisphere, and their causative factors have been drawing increasing attention in recent years. As the first in-depth study on the mechanisms of a snowstorm associated with a low-level cold front (LLCF) and low-level westerly jet (LLWJ) in the western mountainous region of the Junggar Basin, Xinjiang, based on both observations and numerical simulation, the major findings of this work are as follows: At the early stage, instabilities were mainly dominated by inertial instability (II) occurring near the core region of the LLWJ, while the lower level was mainly controlled by the baroclinic component of moist potential vorticity (MPV2), which was mainly contributed by the vertical shear of the horizontal wind, which is also located near the LLWJ. At the later stage, II was released significantly, whereas the MPV2 still supported snowfall clouds. Further analysis based on the decomposition of the frontogenetical forcing required for the release of the instabilities indicated that the slantwise term was the major contributor, whereas convergence and deformation also played significant roles at low levels above the windward slope. The slantwise term resulted from the combined effects of baroclinicity due to the LLCF and the inhomogeneity of the momentum due to the LLWJ.
