沙漠地区边界层高度的提高与尘卷风起沙量的变化

Improvement of planetary boundary layer height and variation of dust devil emission in desert areas

在YSU(Yonsei University)边界层参数化方案的基础上,采用一种经验修正边界层RYSU(Revised YSU)方案,其模拟的边界层高度与观测相吻合.同时利用尘卷风起沙方案,获得了2019年腾格里沙漠夏季尘卷风起沙量的时空分布,结果表明,在08:00~18:00时,RYSU方案模拟的整点尘卷风瞬时起沙量和起沙范围均高于YSU方案,前者的起沙量和范围最大的时刻是15:00时,较后者迟1h,它与腾格里沙漠观测的尘卷风出现频率更接近.采用RYSU方案6~8月研究区每日的总起沙量几乎是采用YSU方案的3倍左右,RYSU方案估算的最大瞬时起沙量比YSU方案更接近用观测的边界层最大高度计算的值.

On the basis of the YSU(Yonsei University)boundary layer parameterization scheme,an empirical revised boundary layer RYSU scheme was adopted in this paper,whose simulated boundary layer height was consistent with the observation.Meanwhile,the dust devil emission scheme was applied to obtain the spatial and temporal distribution of the summer dust devil’s dust emission in Tengger Desert in 2019.The results revealed that from 08:00 to 18:00,the dust devil’s instantaneous dust emission and dust range simulated by the RYSU scheme were higher than those of the YSU scheme.The time when the dust emission and the range of the former was the largest was 15:00,which was one hour later than the latter.It was closer to the occurrence frequency of the dust devil observed in the Tengger Desert.Furthermore,the total daily dust devil emission in the study area from June to August with the RYSU scheme was almost three times higher than with the YSU scheme,and the maximum instantaneous dust devil emission estimated with the RYSU scheme was closer to the value calculated with the maximum height of the observed boundary layer than with the YSU scheme.