In China's solar-rich regions

annual radiation can reach up to 6000MJ/m2

offering exceptionally abundant solar energy resources. Lhasa

in the Tibet Autonomous Region

serves as a representative case. As a critical spatial component for passively regulating the indoor thermal environment of shopping malls

atrium design parameters significantly influence temperature evenness

fluctuation amplitude

and thermal comfort levels. Therefore

optimizing atrium design in solar-enriched areas is essential to improve thermal performance. Although previous research has examined the impact of atrium design parameters

most studies have focused on regions with moderate solar radiation

such as hot-summer and warm-winter zones

or extremely cold climates. Very limited attention has been paid to solar-rich regions. To address this gap

this study conducted field measurements of indoor and outdoor thermal environments in two shopping malls in Lhasa. Using EnergyPlus simulation

the individual and combined effects of three key atrium design parameters including atrium height

aspect ratio

and platform location on indoor thermal conditions and thermal comfort of the shopping mall were quantitatively analyzed. The results indicate that: 1) Indoor air temperature is more strongly influenced by the atrium space than by the floor location

with the atrium helping to prevent sharp temperature increase on specific floors. 2) The average indoor relative humidity in malls with atrium was 27.64 % in winter and 32.24 % in summer

reflecting significant dryness caused by increased solar heat gain and air stratification; thus

humidification facilities are recommended. 3) Platform location significantly affects thermal distribution. Lower platforms intensify heat accumulation in the atrium

leading to localized overheating and reduced comfort. though thermal comfort may improve in surrounding rooms. This study fills a gap in the literature by investigating atrium design impacts in solar-rich regions and provides useful insights for the design and retrofit of atrium spaces in shopping malls exposed to strong solar radiation.