An investigation into the vertical structures of low‐altitude atmosphere over the Central Taklimakan Desert in summer

Abstract

In this study, 1-month continuous radiosonde observational data were applied to present the low-altitude vertical structures and their evolutions over the Central Taklimakan Desert (CTD). The primary focus is to highlight the vertical structures near the ground with the high-resolution (10 m in height and 6 hr in time) radiosonde data. One of the unique features evident in our results is an obvious diurnal transition in lower layers near the ground due to strong surface heating or cooling. Unlike a traditional vertical structure in the boundary layer observed over a nondesert surface, both superadiabatic and inversion layers are distinct during the day. More specifically, the superadiabatic layer is obvious in the daytime because of strong solar radiation over the desert, and the superadiabatic can reach up to 0.2 km. In contrast, an apparent inversion layer forms in the nighttime due to the surface cooling. It is found that the surface forcing mainly dominates the structures in the boundary layer. At last, the vertical structures from the observations are compared with those from the ERA-Interim and MERRA2 reanalysis data sets. The results indicate that both reanalysis products can provide similar vertical profile patterns and diurnal variations. However, the diurnal transitions of temperature and wind profiles over the CTD are underestimated severely by both reanalysis data. Besides, the reanalysis data sets completely miss the superadiabatic near the ground in the daytime.

East Asia Reanalysis System (EARS)

“…The transition, from stable to convective and back to stable condition, is consistent with the diurnal variation of solar radiation (Yin et al, 2021). In general, both the EARS and ERA-Interim are able to reproduce similar diurnal transitions as in the observations.…”

“…have little influence on the reanalysis data. Note that these data have not been applied to any weather forecasting or reanalysis systems (including global and regional systems), which should be an excellent source of independent observations (Huang et al, 2021). The radiosonde observational station (marked with a black star in Fig.…”

East Asia Reanalysis System (EARS)

“…The transition, from stable to convective and back to stable conditions, is consistent with the diurnal variation of solar radiation (Yin et al, 2021). In general, both EARS and ERA-Interim are able to reproduce similar diurnal transitions to the observations.…”

“…The central Taklimakan Desert is far from other observation sites, where the assimilated observations have little influence on the reanalysis data. Note that these data have not been applied to any weather forecasting or reanalysis systems (including global and regional systems), which should be an excellent source of independent observations (Huang et al, 2021). The radiosonde observational station (marked with a black star in Fig.…”

“…The study also demonstrates the potential use of the EARS data for applications over East Asia and proposes further plans to provide the latest reanalysis in real-time operation mode. Simple data and updated information are available on Zenodo at https://doi.org/10.5281/zenodo.7404918 (Yin et al, 2022), and the full datasets are publicly accessible on the Data-as-a-Service platform of the China Meteorological Administration (CMA) at http://data.cma.cn (last access: 19 May 2023).…”