The Chinese thermal comfort dataset.

Heating and cooling in buildings accounts for over 20% of total energy consumption in China. Therefore, it is essential to understand the thermal requirements of building occupants when establishing building energy codes that would save energy while maintaining occupants' thermal comfort. This paper introduces the Chinese thermal comfort dataset, established by seven participating institutions under the leadership of Xi'an University of Architecture and Technology. The dataset comprises 41,977 sets of data collected from 49 cities across five climate zones in China over the past two decades. The raw data underwent careful quality control procedure, including systematic organization, to ensure its reliability. Each dataset contains environmental parameters, occupants' subjective responses, building information, and personal information. The dataset has been instrumental in the development of indoor thermal environment evaluation standards and energy codes in China. It can also have broader applications, such as contributing to the international thermal comfort dataset, modeling thermal comfort and adaptive behaviors, investigating regional differences in indoor thermal conditions, and examining occupants' thermal comfort responses.

Degraded frozen soil and reduced frost heave in China due to climate warming.

Frost heave hazard is the uneven uplift of the ground surface due to the freezing of water and the expansion of ice bodies in soil, especially in seasonally frozen soil. First, this study quantified temporal and spatial variations of frozen soil, the active layer and frost heave in China in the 2010s. Subsequently, the study predicted the changes in the frozen soil, active layer, and frost heave for the 2030s and 2050s under the SSP1-2.6, SSP2-4.5, and SSP5-8.5 climate scenarios. The permafrost will have degraded to seasonally frozen soil, and the seasonally frozen soil will have a reduced depth or even become non-frozen. By the 2050s, the area of permafrost and seasonally frozen soil will have degraded by 17.6-59.2 % and 4.8-13.5 %, respectively. There is a 19.7-37.2 % reduction in area for seasonally frozen soil when the maximum depth of the seasonally freezing layer (MDSF) < 1.0 m, 8.8-18.5 % when 2.0 < MDSF <3.0 m, and an increase up to 13 % when 1.0 < MDSF <2.0 m. The area with a frost heaving <1.5 cm, 1.5-3.0 cm, 3.0-5.0 cm will have been reduced by 16.6-27.2 %, 18.0-24.4 %, and -8.0-17.1 % in the 2050s, respectively. Areas where permafrost degrades to seasonally frozen soil require attention when managing frost heave hazards. This study will help guide engineering and environmental practices in cold regions.

Unraveling of permafrost hydrological variabilities on Central Qinghai-Tibet Plateau using stable isotopic technique.

Permafrost degradation on the Qinghai-Tibet Plateau (QTP) will substantially alter the surface runoff discharge and generation, which changes the recharge processes and influences the hydrological cycle on the QTP. Hydrological connections between different water bodies and the influence of thawing permafrost (ground ice) are not well understood on the QTP. This study applied water stable isotopic method to investigate the permafrost hydrological variabilities in Beiluhe Basin (BLB) on Central QTP. Isotopic variations of precipitation, river flow, thermokarst lake, and near-surface ground ice were identified to figure out the moisture source of them, and to elaborate the hydrological connections in permafrost region. Results suggested that isotopic seasonalities in precipitation is evident, it is showing more positive values in summer seasons, and negative values in winter seasons. Stable isotopes of river flow are mainly distributed in the range of precipitation which is indicative of important replenishment from precipitation. δ18O, δD of thermokarst lakes are more positive than precipitation, indicating of basin-scale evaporation of lake water. Comparison of δI values in different water bodies shows that hydrology of thermokarst lakes was related to thawing of permafrost (ground ice) and precipitation. Near-surface ground ice in BLB exhibits different isotopic characteristics, and generates a special δD-δ18O relationship (freezing line): δD=5.81δ18O-23.02, which reflects typical freezing of liquid water. From isotopic analysis, it is inferred that near-surface ground ice was mainly recharged by precipitation and active layer water. Stable isotopic and conceptual model is suggestive of striking hydrological connections between precipitation, river flow, thermokarst lake, and ground ice under degrading permafrost. This research provides fundamental comprehensions into the hydrological processes in permafrost regions on QTP, which should be considered in investigating the influence of thawing permafrost on the hydrological cycle on QTP.