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In recent years, China has accelerated the development of oiltea camellia industry and promoted the expansion of oiltea camellia cultivation nationwide, necessitating a refined agricultural climate zoning for oiltea camellia cultivation across the country. Considering soil factors is crucial for enhancing the precision of agricultural climate zoning for oiltea camellia. Therefore, based on the selection of potential climate factors affecting oiltea camellia cultivation distribution, as well as land conditions such as slope and soil thickness, dominant climate factors are analyzed using maximum entropy (MaxEnt) model and ArcGIS technology. It provides a refined climate zoning of oiltea camellia cultivation in China based on the joint effect of climate and land, identifying the potential for expansion and offering a scientific basis for the planning and implementation of oiltea camellia expansion. Results indicate the dominant climate factors affecting oiltea camellia cultivation distribution in China are the average temperature in January, accumulated temperature above or equal to 10 ℃, consecutive days with minimum temperature equal to or below -10 ℃, and annual cumulative precipitation. Taking into account the impact of slope and soil thickness on climatic suitability analysis, the climate zoning for oiltea camellia is divided into four suitability levels: The most suitable, more suitable, suitable region, and unsuitable region. The area for the most suitable region is 3.003×107 hm2, more suitable region is 2.858×107 hm2, and suitable region is 1.458×107 hm2.The precision of regional climate zoning for oiltea camellia cultivation is enhanced, reducing the suitable planting area for oiltea camellia by two-thirds compared to those not considering land factors. Suitable cultivation areas for oiltea camellia in China are in the region south of Yangtze River, especially from Sichuan Basins to the Qinling Mountains to the south of Huai River, and the east of Yungui Plateau to the coastal areas. Compared to the current planting area and range, oiltea camellia in China has significant potential for expansion. The potential planting boundaries, considering the joint effect of climate and land, tend to be further north. It suggests significant potential for expansion in the distribution of oiltea camellia in China. Therefore, when planning the layout of oiltea camellia cultivation, in addition to considering major planting areas such as Hunan, Jiangxi, Guangxi and Hubei, provinces with significant expansion potential such as Yunnan, Sichuan, Guangdong and Chongqing should also be taken into account, and their planting areas should be appropriately increased.

Agroclimatic regionalization is an effective way to utilize agricultural climate resources in a reasonable manner. Accurate and objective agroclimatic regionalization plays a great directive role in ecological layout and decision support for agriculture farming. The purpose of this article was to investigate the influence of climate change on agroclimatic regions in China. Following the same regionalization principle concept as the theory and techniques of agroclimatic regionalization, three agroclimatic regions, the Tibetan High Cold Region (THCR), Northwest Arid Region (NAR), and Eastern Monsoon Region (EMR) were identified in China. The changes in the three agroclimatic regions were analyzed from 1961 to 2020 in the past and from 2006 to 2060 in the future. Future changes in agroclimatic regions were estimated from 2006 to 2030 and from 2031 to 2060 under scenarios RCP2.6, RCP4.5, and RCP8.5 for greenhouse gas emissions. The borders of agoclimatic regions had changed as a result of global climate warming and precipitation variability. There was a surplus in the geographical displacement and range of agroclimatic region borders in 1991 to 2020, especially when compared to those in 1961–1990. The TCHR exhibited significant spatial variation, with its northeast corner shifting nearly 170 km to the southwest. In the future, the area ratio of the THCR will be 26% by 2031–2060 under the RCP8.5 scenario, with the highest decline (1% compared to that in the reference period of 1981–2005), while under the RCP4.5 and RCP2.6 scenarios it will stabilize the area ratio at 27%. The eastern boundary of the NAR will migrate south or east, while the center boundary will rise northward. Under all three climatic scenarios, the area ratio will be 25% (down 1%). The range of the EMR will expand. The area ratio of the EMR will increase by 1% under the RCP2.6 and RCP4.5 scenarios and by 2% under the RCP8.5 scenario. Overall, our study may facilitate an in-depth understanding of agroclimatic regions changes and thus provide a scientific reference for the distribution of agricultural production and sustainable development under climate change in China. [ABSTRACT FROM AUTHOR]

To project local precipitation at the existing meteorological stations in China's Beijing-Tianjin-Hebei region in the future, local daily precipitation was simulated for three periods (2006–2030, 2031–2050, and 2051–2070) under RCP 4.5 and RCP 8.5 emission scenarios. These projections were statistically downscaled using a weather generator (BCC/RCG-WG) and the output of five global climate models. Based on the downscaled daily precipitation at 174 stations, eight indices describing mean and extreme precipitation climates were calculated. Overall increasing trends in the frequency and intensity of the mean and extreme precipitation were identified for the majority of the stations studied, which is in line with the GCMs' output. However, the downscaling approach enables more local features to be reflected, adding value to applications at the local scale. Compared with the baseline during 1961–2005, the regional average annual precipitation and its intensity are projected to increase in all three future periods under both RCP 4.5 and RCP 8.5. The projected changes in the number of days with precipitation are relatively small across the Beijing-Tianjin-Hebei region. The regional average annual number of days with precipitation would increase by 0.2~1.0% under both RCP 4.5 and RCP 8.5, except during 2031–2050 under RCP 8.5 when it would decrease by 0.7%. The regional averages of annual days with precipitation ≥25 mm and ≥40 mm, the greatest one-day and five-day precipitation in the Beijing-Tianjin-Hebei region, are projected to increase by 8~30% during all the three periods. The number of days with daily precipitation ≥40 mm was projected to increase most significantly out of the eight indices, indicating the need to consider increased flooding risk in the future. The average annual maximum number of consecutive days without precipitation in the Beijing-Tianjin-Hebei region is projected to decrease, and the drought risk in this area is expected to decrease. [ABSTRACT FROM AUTHOR]