Low-level Jest and Its effects on Dust Emission over Taklimakan Desert

Abstract:

Nocturnal Low-Level Jets (NLLJs) are important for dust emission and its transport. Combining the ERA-Interim reanalysis and satellite aerosol observations, we define a NLLJ detection method and show the climatologic characteristics of NLLJ over the Taklimakan Desert for the first time. The NLLJs frequently occur more than 55% of nights, are primarily easterly and northeasterly wind, and typically appear at 120-400 m with the speed of 4-10 ms^-1. It is also found that the most NLLJs are situated above the top of the inversion during summer season while embedded in the inversion layer during winter. Although the NLLJs appear all year long over the Taklimakan Desert, composite studies shown that the NLLJs can only play an important role for the dust emission during summer and autumn. Due to weak NLLJ and convection, less momentum can be mixed down for dust emission in winter and spring.