Recently, GU Wenbo, a PhD candidate at the Optical Astronomy and Technology Application Research Division of the Xinjiang Astronomical Observatory, Chinese Academy of Sciences, with his supervisor Prof. Ali Esamdin and the site-testing team, conducted an in-depth study on the spatial and temporal distribution characteristics of optical turbulence in the atmospheric surface layer (ASL) at Muztagh-Ata site. The results  have been published in the Monthly Notices of the Royal Astronomical Society.（2024,MNRAS,535,1193）

Using the five levels of ultrasonic anemometers, six levels of high-precision temperature and humidity sensors installed on a 30-meter tower, along with long-term and multi-height on-site observational data, the researchers  systematically analyzed the variation of optical turbulence parameters (including optical turbulence intensity and seeing) within the framework of Kolmogorov's locally homogeneous and isotropic turbulence theory, and also explored the relationships between these parameters and other atmospheric factors, including surface temperature inversion, Reynolds number, and wind speed.

The results showed that the influence of turbulence on optical observations gradually decreased with the increasing of heights. With a median seeing of 0.24 arcseconds near surface layer between 6-30 meters in height, ASL exhibits weaker and more stable optical turbulence at night than the daytime, providing ideal conditions for high-quality astronomical observations. The surface temperature inversion was found to be closely related to improved seeing. Under the inversion conditions and low wind speeds, the optical turbulence at the site became more stable, providing more favorable conditions for optical astronomical observations. 

This study provides an important perspective for evaluating the Muztagh-Ata site.

This work is supported by the National Natural Science Foundation of China (Grant No. U2031209). 

Diurnal Variation of Atmospheric Surface-Layer Seeing at Muztagh-ata site and  Its  Correlation  with  Parameters  Such  as  Temperature  Inversion,  Reynolds Number, and Wind Speed.