Climatic Regions Of China Research Articles

Soil available phosphorus and pH are key factors affecting the site index of Larix kaempferi plantations in China

Assessing the quality of forest sites is crucial for evaluating the potential productivity of forests and formulating effective management strategies. Therefore, it is essential to understand how environmental variables affect the site quality. This study focuses on quantifying the effects of 44 different environmental variables including climate, topography, and soil properties on the site index of Larix kaempferi plantations in three different climate regions in China, utilizing the random forest algorithm. L. kaempferi site index was determined from stem analysis data by felling dominant trees from 51 even-aged stands. The results indicated that the proposed random forest model explained ~59.47% of site index variations. Among many environmental variables, available phosphorus, pH, degree-days above 5°C (DD5), and spring mean maximum temperature (Tmax_MAM) had significant effects on the site index (P < 0.05), and the importance of soil chemical properties generally exhibits relatively larger effects on the site index than climate variables and topography variables. The partial dependence analysis revealed that the L. kaempferi plantations had maximum values at ~30 mg/kg of available phosphorus in the first soil layers, 30 mg/kg of available phosphorus in the second soil layers, 20 mg/kg of available phosphorus in the third soil layers, the DD5 between 2,600and 3,000°C, and Tmax_MAM ~15°C. Our findings attempt to provide a better understanding of the site–growth relationship.

Sustainable Design Methods Translated from the Thermodynamic Theory of Vernacular Architecture: Atrium Prototypes

In the context of China’s sustainable development and dual carbon goals, research on thermodynamic architecture theory and vernacular architecture increasingly aligns with international trends, developing distinct characteristics. This research addresses the challenge of rapid changes in the built environment by focusing on climate adaptability and passive technologies. However, the development of thermodynamic theory in vernacular architecture faced technical limitations in the early 21st century and was later overshadowed by the industry’s reliance on active technologies to meet green building standards, resulting in a reduced role for architects in the green building field. This article traces the origins of passive architecture, rooted in vernacular architecture, and applies thermodynamic theory to explore architectural prototypes. It examines the theoretical feasibility of architectural design in achieving low-carbon and sustainable goals, aiming to fill a gap in thermodynamic theory within the broader context of sustainable architectural development. After demonstrating the various passive prototypes inherent in vernacular architecture, this paper proposes a courtyard prototype focused on residential comfort for design translation and analysis. The research methods employed include bioclimatic charting, balance point temperature analysis in time series, and extensive computer simulations. Through the process of prototype extraction, performance analysis, validation, and optimization, the paper systematically discusses sustainable design methods within the framework of thermodynamic architecture theory. It also provides practical demonstrations of these methods across four distinct climate regions in China. By translating vernacular architectural designs, this research systematically organizes the theoretical framework for architects’ early involvement in low-carbon and green building design, offering a theoretical foundation for initiating the design process through prototype translation while guiding the generation of green ecological buildings.

Effects of Low-Temperature Stress on Physiological Characteristics and Microstructure of Stems and Leaves of Pinus massoniana L.

Pinus massoniana L. is one of the most important conifer species in southern China and is the mainstay of the forest ecosystem and timber production, yet low temperatures limit its growth and geographical distribution. This study used 30-day-old seedlings from families of varying cold-tolerance to examine the morphological traits of needles and stems, chlorophyll fluorescence characteristics, protective enzymes, and changes in starch and lignin under different low-temperature stresses in an artificial climate chamber. The results showed that the seedlings of Pinus massoniana exhibited changes in phenotypic morphology and tissue structure under low-temperature stress. Physiological and biochemical indexes such as protective enzymes, osmoregulatory substances, starch, and lignin responded to low-temperature stress. The cold-tolerant family increased soluble sugars, starch grain, and lignin content as well as peroxidase activity, and decreased malondialdehyde content by increasing the levels of actual photochemical efficiency (ΦPSII), electron transport rate (ETR), and photochemical quenching (qP) to improve the cold tolerance ability. This study provides a reference for the selection and breeding of cold-tolerant genetic resources of Pinus massoniana and the mechanism of cold-tolerance, as well as the analysis of the mechanism of adaptation of Pinus massoniana in different climatic regions of China.

Semi-arid rather than arid regions of China deserve the priority in drought mitigation efforts

The integration of drought assessment, mitigation priority analysis and mitigation measures development is a forward-looking strategy to achieve water resources allocation, implement anti-drought techniques and formulate corresponding mitigation measures strategies. However, since most drought indices cannot be based on surface water-balance to estimate water demand for drought recovery, there is a gap between drought assessment and proactive drought mitigation. Here, we established the Standardized Water Availability Index (taking water yield as surface water deficit/surplus) to identify hydrological drought, and further use it to determine the water demand for hydrological drought mitigation. On that basis, a comprehensive framework, integrating with drought assessment-resilience-recovery and water scarcity stress, was proposed to investigate the hydrological drought mitigation priority for basins in different climate regions in China. The results show that non-humid river basins have greater water scarcity stress, lower resilience to hydrological drought, but less water demand for hydrological drought mitigation (3 mm ∼ 7 mm in mild drought, 5 mm ∼ 14 mm in moderate drought, 7 mm ∼ 21 mm in severe drought). In contrast, humid river basins have greater water demand for hydrological drought mitigation (15 mm ∼ 49 mm in mild drought, 27 mm ∼ 93 mm in moderate drought, 32 mm ∼ 119 mm in severe drought), but higher resilience to hydrological drought. The densely populated semi-arid river basins in China should be given priority attention in mitigating hydrological drought on account of their greatest water scarcity stress, lower drought resilience, and less water demand for drought mitigation. This work highlights the complexity of the hydrological drought mitigation, and our findings can help stakeholders to make precise drought mitigation measures and adapt drought-relative water management.

Evaluating the spatiotemporal dynamics of driving factors for multiple drought types in different climate regions of China

Extreme weather events and natural hazards are increasingly prevalent with global warming, making it imperative to focus on the driving factors and dynamic changes associated with drought—a disaster with widespread impacts and significant losses. This study used a longtime-series of ERA5 reanalysis data to elucidate the dynamic change characteristics of direct and indirect driving factors across China. Ground observation data spanning an extended period were used to estimate the performance of the reanalysis data. The selected driving factors for drought included precipitation (PRE), potential evapotranspiration, soil moisture (SM), bare soil evapotranspiration (BSET), vegetation canopy evapotranspiration (VCET), subsurface runoff (SUBRO), surface runoff (SURRO), temperature (TEM), specific humidity, and near-surface wind speed (WS). Meteorological drought, hydrological drought, and agricultural drought were delineated using the Standardized Precipitation Evapotranspiration Index, Standardized Runoff Index, and Standardized Soil Moisture Index. The Random Forest method was used to ascertain the relative importance of driving factors and their main contributions to different types of droughts. The findings revealed that ERA5 exhibited great simulation performance compared to observational data. However, the correlation coefficient of SM might be relatively lower than that of other driving factors across China. Notably, BSET and PRE exhibited higher relative importance degrees (RID) for meteorological drought in subregions 1, 2, and 3. At the same time, SUBRO demonstrated a more statistically significant influence in subregions 3, 4, and 5. SURRO played a statistically significant role in subregion 1. Moreover, BSET and PRE were pivotal for meteorological drought in northern China, whereas VCET assumes importance for hydrological drought in southern China and the North China Plain. Across different types of droughts, PRE, SM, and TEM generally exhibited relatively large RID values in China. The dynamic changes in RID for both direct and indirect driving factors varied for different drought types across different subregions of China. Notably, the RID displayed contrasting dynamic changes between PRE and BSET for meteorological drought in most subregions. Additionally, the degree of relative importance of near-surface WS tended to be lower for hydrological drought across various subregions. This study contributed to a deeper understanding of drought evolution and enhanced monitoring efforts.

Structure and regional optimization of a phase change material Trombe wall system

Trombe walls (TW) have been an effective passive solar technology for enhancing building energy efficiency. Considering the thermal storage and regulation capabilities of phase change materials (PCM) in solar energy utilization, TW with PCM (PCMTW) were designed and optimized to further improve building energy performance. This study investigated the combined effects of PCM phase change temperature, PCM location and ventilation strategies on a single-layer PCMTW. Moreover, a novel double-layer PCMTW was proposed and evaluated across various climate regions of China in consideration of the effect of PCM phase change temperature combinations. Results show that the single-layer PCMTW with PCM22 placed next to inner surface and ventilation achieved the lowest annual energy consumption. The selection of PCM phase change temperature was crucial for various climatic conditions. Compared to the traditional building, the highest heating energy-saving was 118.16 kWh/m2 achieved in Changchun with PCM22 + 28, and the highest cooling energy-saving was 45.71 kWh/m2 achieved in Haikou with PCM25 + 28. Additionally, the double-layer PCMTW was recommended for climate regions where the daily average temperature and the daily average solar emissivity were 20–25 °C and below 4 kWh/m2 in summer, and below 10 °C and 2–6 kWh/m2 in winter.

Improving the sustainability of milk production across different climate regions in China

Unprecedented climate change and ever-increasing demand for dairy products call for solutions that can ensure stable and sustainable milk production in different climate regions. Fully-enclosed dairy farms act as a promising option while its economic and environmental performance is poorly studied. Here, we evaluated the potential of improvement on milk yield and milk supply inequality among regions by developing fully-enclosed dairy farms throughout China, as well as their economic feasibility and environmental impacts. Results showed that: (1) fully-enclosed dairy farms present a 33 % higher milk yield per lactating cow together with a 38 % lower coefficient of variation in milk production across climate regions than semi-enclosed ones; (2) greenhouse gas and NH3 emissions of fully-enclosed dairy farms are effectively declined compared with semi-enclosed ones; (3) the inequality in fresh milk supply can be reduced by 51 % through strategically locating fully-enclosed dairy farms around cities; and (4) industrial optimization on the internal structure of fully-enclosed dairy farms is economically feasible across different climate regions in China, with an average improvement of 54 %. Our analysis suggests to develop fully-enclosed dairy farms surrounding urban areas for meeting milk demand alongside positive effects on environmental sustainability, which also offers a lens for the livestock sector to define better policies that improve the sustainability of milk production on the planet.

Evaluation of energy performance and environmental benefits for transcritical CO2 thermal system in high-speed trains

The conventional air conditioning system used in high-speed railways has limitations in heating performance and environmental impact, necessitating the exploration of alternative refrigerants. The transcritical CO2 system has gained popularity due to its exceptional heating efficiency and environmental benefits. This study aims to evaluate the energy and environmental potentials for transcritical CO2 systems in high-speed trains based on four-vertical-and-four-horizontal railway lines within different climatic regions of China. A high-fidelity transcritical CO2 system model was first developed and validated through experiments. Then, a comprehensive energy and environmental evaluation method was proposed and applied to the four-vertical-and-four-horizontal railway lines. The results indicated that the transcritical CO2 system had a superior heating performance and competitive cooling performance based on daily and annual operations. Furthermore, the transcritical CO2 system exhibited significant environmental advantages with lower total life cycle climate performance for all lines, with an average emissions reduction ratio of 17.6% and a maximum emissions reduction ratio of 26.98%. These findings highlight the competitive energy performance and outstanding environmental benefits offered by transcritical CO2 systems as promising alternatives to air conditioning systems in railway transportation.

Transcritical CO2 system with two-stage throttling for supermarkets: Field tests, energy and emission performance assessment in China

Transcritical CO2 system is eco-friendly for the application of refrigeration and cooling in supermarket. To evaluate the applicability of transcritical CO2 supermarket refrigeration system in China with different climate regions, this study focuses on the field tests of a transcritical CO2 two-stage throttling system in a supermarket in Suzhou, Jiangsu Province, China. Furthermore, based on the tested data, the system energy and emissions performance models of four system configurations are also developed and validated, including the system integrated with an internal heat exchanger, a parallel compression, and mechanically assisted subcooling. In order to improve the usability of the system in different climatic zones, 40 cities were selected for calculation in China. Five representative cities (Beijing, Harbin, Xiamen, Chongqing, and Kunming) located in different climate regions of China are selected, and the annual performance factor and life cycle climate performance (LCCP) are determined to evaluate the application potential of the CO2 refrigeration systems in different climate conditions. The tested results show the operation mode of transcritical and subcritical changes occurs at an ambient temperature of about 27 °C, at which the coefficient of performance (COP), compressor discharge pressure and discharge temperature change dramatically. The simulation results demonstrate that the mechanical subcooling system shows the best performance. The annual performance factor can be improved by 18.69 % when the mechanical subcooling is adopted. For the case of the system used in Xiamen by using mechanical subcooling, the carbon emissions can be reduced by 19.3 %.

Relation between soil glycerol dialkyl glycerol tetraethers and temperature in different climatic regions in China

AbstractTemperature variation in the past periods can provide valuable insights into the characteristics and driving mechanisms of current global warming and future changes. Branched glycerol dialkyl glycerol tetraethers (brGDGTs) are commonly used to as a temperature proxy to quantitatively reconstruct past temperature changes. However, it still remains unclear whether the relation between brGDGTs and temperature is influenced by other environmental factors, thereby affecting the accuracy of quantitative reconstructions. A comprehensive analysis of the relation between brGDGTs and temperature across various climate regions can greatly enhance the accuracy of reconstructing past temperature changes. Here, we investigate the distribution patterns of soil brGDGTs using 28 new topsoils collected from altitudes ranging from 2100 to 4000 m.a.s.l. in the Hengduan Mountains in the southeastern margin of the Tibetan Plateau (TP), compiled previously published soil brGDGT data in China. Our results reveal distinct distribution patterns of soil brGDGTs between humid and arid regions. Furthermore, we further investigated the correlation between brGDGT indices and various environmental factors from both altitudinal and regional scales. At the altitudinal scale, brGDGT indices exhibit a stronger correlation with mean annual air temperature (MAAT) in alkaline soils (pH > 7) than that in acidic soils (pH < 7). At the regional scale, this correlation is higher in alkaline soils than that in acidic soils as well and is stronger in humid soils (mean annual precipitation [MAP] > 800 mm) than that in semi‐humid and semi‐arid soil (400 < MAP < 800 mm) and arid soil (MAP < 400 mm). In addition, brGDGT‐inferred temperature is more affected by MAP in humid alkaline soils but less affected in humid acidic soils. Therefore, caution is needed to use suitable brGDGT index for palaeotemperature reconstructions in various climate regions.

Energy performance of buildings with multi-ribbed composite wall structural system

Multifunctional multi-ribbed composite wall (MRCW) structural system has been increasingly used due to its dual load bearing and energy saving capacities. Most of existing studies were focused on its mechanical properties. This paper aims to evaluate its energy saving effect. To this end, two models are constructed using EnergyPlus for the same residential building in Beijing, China, but with different systems of MRCW and shear wall. The dynamic simulation of hourly energy consumption throughout one year is carried out at the building operation stage. The results show that the heating energy consumption is higher than the cooling energy consumption. The total energy consumption of the MRCW system can be reduced by 11.4 % compared with that of the shear wall system. Further, the annual energy consumption of the residential building models in five typical climate regions in China with different orientations is simulated. The results show that the energy saving of MRCW system range from 5 % to 13 % in the five regions when compared with shear wall system, and the absolute value of energy saving is the largest in severe cold and cold regions. The north-south orientation is the best energy-saving orientation. Based on this study, it can be concluded that, other than carrying load, MRCW system can also save energy compared with shear wall system, especially in severe cold and cold regions.

Research on the optimization of the clean heating system for regional residential buildings based on the multi-objective optimization strategy

For the residential building district heating (RBDH) system, choosing the appropriate combination of heat sources according to local conditions is the key to improving economic efficiency. In this study, three climatic regions in China were selected, namely, a hot summer and cold winter region, cold region, and severe cold region. Among them, Nanjing, Tianjin, and Shenyang were selected as typical representative cities in the hot summer and cold winter region, cold region, and severe cold region, respectively. Taking the levelized cost of heat (LCOH) as the economic evaluation index and considering the carbon emission cost of the system operation, the energy consumption and the CO2 emissions were analyzed. TRNSYS software was used to simulate and analyze the system performance. The multi-objective optimization based on a genetic algorithm was proposed to optimize system parameters. From an economic point of view, the SA system was suitable for the hot summer and cold winter region, the SAS system was suitable for the cold region, and the SE system was suitable for the severe cold region. The operation control strategy based on quality adjustment can reduce heating energy consumption and maintain indoor temperatures at approximately 20°C. The proportion of clean energy heating in the optimized heating system decreased after the multi-objective optimization strategy. However, the initial investment and maintenance costs of the system were reduced, which reduced the LOCH of the system. Therefore, the multi-objective optimization strategy can effectively reduce the heating costs.

Experimental and numerical investigation on energy-saving performance of radiative cooling coating for metal container office

Radiative cooling coating (RCC) embedded with randomly distributed particles is a scalable, cost-effective, and reliable material that can enhance the energy efficiency of the building envelope. Many RCC materials with excellent cooling potential have been developed recently. However, there is a lack of holistic experimental and numerical demonstrations of RCC’s energy-saving potential in real-world applications. In this research, by randomly distributing commonly used functional fillers into a polymeric matrix, an RCC material was developed and applied to an in-service metal container office at a construction site in Hong Kong. Parallel tests were conducted using another identical container office with a conventional white coating for comparison. The inner and outer surface temperatures of the two container offices, their indoor air temperature, and the electricity consumption of their air-conditioner system were measured and compared. The field-test results indicated that the RCC could reduce the container office’s surface temperature by up to 18 ℃ and save 23.5% of electricity consumption under Hong Kong’s climate compared to the conventional white coating. Furthermore, the numerical simulation model for the metal container office was developed in EnergyPlus and validated by the experimental results. Then, the simulation model was used to evaluate the overall energy-saving performance of the RCC in five different climatic regions in China considering different solar reflectivity values. It was found that in tropical or subtropical cities such as Hong Kong, with the solar reflectivity of the RCC increasing from 85% to 95%, the annual energy load saving rate increases from 19.2% to 30.9%. In other climatic regions, the increase in solar reflectivity will bring a significant increase in the heating load penalty that outweighs the cooling load savings. Therefore, in regions with hot summers and cold winters, optimizing the solar reflectivity of RCC by considering the offset between the cooling load saving and heating lead penalty is highly desirable in order to achieve the best annual energy-saving performance.

Photovoltaic output power estimation model based on multi-meteorological variable dimension reduction and improved variational mode decomposition algorithm

ABSTRACT The instability and intermittence of photovoltaic (PV) power generation challenge the large-scale integration of PV power generation systems into the power grid and the development of energy storage systems. To accurately predict the output power of PV power generation, a power prediction model based on the optimized variational modal decomposition (OVMD)-adaptive t-distribution sparrow search algorithm (tSSA)-least squares support vector machine (LSSVM) algorithm was built. The performance of the model was then verified by three-year meteorological data and real-time PV output power data of two different climatic regions in China. The mean absolute percentage error (MAPE) and root mean square error (RMSE) of this model were less than 3.1% and 0.40, respectively, and the determination coefficient (R2) of this model was greater than 95%. Moreover, the prediction accuracy was greatly improved compared to models based on the support vector machine (SVM), LSSVM, variational modal decomposition (VMD)-LSSVM, and VMD-SSA-LSSVM algorithms. Finally, by performing dimension reduction of meteorological variables related to PV output power, the performance of the proposed OVMD-tSSA-LSSVM model was further improved.

Influence of self-shading building form on indoor solar gains and energy performance in different climates of China

Self-shading building form has a significant influence on indoor solar gains and energy performance. This paper presented a methodology for quantifying self-shading building forms, which categorized them into three types: inclined, cantilevered, and hybrid (inclined and cantilevered). The prediction model for the quantitative indexes and solar heat gains through windows was established through regression analysis, while the influence of proposed self-shading building forms on energy performance in different climatic regions of China was evaluated and compared. Results suggest that energy-saving potential of the cantilevered type is the highest, followed by the hybrid type. Compared to the south orientation, energy-saving potentials for east and west orientations are more pronounced. As building location changes from south to north, energy-saving potential is increasingly influenced by orientation. The proposed self-shading building forms have a maximum energy-saving potential of 14%, 23%, and 22% for Jinan, Shanghai, and Guangzhou respectively. Finally, corresponding design strategies were suggested to provide guidance and assistance for designers.

The embodiment of the ecological concept and climatic adaptability in the spatial structure of the traditional chinese dwelling with a courtyard

The article analyzes the logic and distinctive features of the structural construction of traditional Chinese dwellings with a courtyard. A detailed comparison of various types of such dwellings located in different geographical and climatic regions of China allows us to identify their compositional features and unique architectural solutions. The focus of the study is on the ecological principles and strategies of climatic adaptation of various compositional types of courtyards that allowed them to effectively cope with climatic challenges over centuries. Attention is drawn to the basic philosophical concept of harmonious coexistence of man with nature, which underlies the design of optimal types of traditional Chinese dwellings, particularly to passive methods of architectural design that contribute to environmental sustainability and climatic adaptation of these dwellings.

An Analysis of the Influence of Cool Roof Thermal Parameters on Building Energy Consumption Based on Orthogonal Design

An analytical hierarchy model of the impact of solar reflectance, thermal emittance, heat transfer coefficient, and heat storage coefficient on building energy consumption was established through the implementation of orthogonal design experiments. The EnergyPlus software (v9.0.1) was utilized to simulate building energy consumption across diverse climatic regions in China, providing essential benchmarks for the orthogonal design. The results of the range analysis consistently indicate that, barring regions characterized by extremely cold climates, solar reflectance emerges as the predominant factor exerting an influence on building energy consumption. As geographical latitude increases, the impact of the heat transfer coefficient becomes progressively larger, while the weight of thermal reflectance concurrently diminishes. Drawing upon the principles rooted in the gradient refractive rate theory and the concept of atmospheric window radiation, a range of high-reflectance and high-emittance cool roof coatings in various colors were meticulously developed. A spectrophotometer was employed to precisely quantify their reflectance properties, and simulations were subsequently conducted to scrutinize their energy-saving characteristics. The results demonstrate that the cool roof coatings that were developed using the methodology described in this paper exhibit substantial enhancements in reflectance, with increases of 0.24, 0.25, 0.37, and 0.35 for the yellow, red, blue, and green cool roofing materials, respectively, in comparison to conventional colored coatings. Under typical summer conditions, these enhancements translate to significant reductions in roof temperatures, ranging from 9.4 °C to 14.0 °C. Moreover, the simulations exploring the cooling loads for the roofs of differing colors consistently revealed remarkable energy savings. These savings were quantified to be 4.1%, 3.9%, 5.5%, and 5.4%, respectively, when compared to conventional coatings of the corresponding colors. These findings offer valuable insights into strategies for optimizing the energy efficiency of buildings through the application of high-reflectance cool roofing materials.

Estimating reference crop evapotranspiration using optimized empirical methods with a novel improved Grey Wolf Algorithm in four climatic regions of China

Accurate estimation of reference crop evapotranspiration (ETo) is crucial for agricultural water management. As the simplified alternatives of the Penman-Monteith equation, empirical methods have been widely recommended worldwide. However, its application is still limited to parameters localization varied with geographical and climatic conditions, therefore developing an excellent optimization algorithm for calibrating parameters is very necessary. Regarding the above requirement, the present study developed a novel improved Grey Wolf Algorithm (MDSL-GWA) to optimize the most recommended ones among three types of ETo methods. After the optimization performance comparison among Least Square Method (LSM), Genetic Algorithm (GA), Grey Wolf Algorithm (GWA), and MDSL-GWA in four climatic regions of China, this study found that the Priestley-Taylor (PT) method was the best radiation-based (Rn-based) method and achieved better performance in temperate continental region (TCR), mountain plateau region (MPR), and temperate monsoon region (TMR) than other types. While the temperature-based (T-based) Hargreaves-Samani (HS) method performed best in subtropical monsoon region (SMR), further attaching better performance among the same type in TMR and TCR, while the Oudin method was the best T-based method in MPR. Moreover, the Romanenko method was better humidity-based (RH-based) in TCR and MPR, whereas the Brockamp-Wenner method exhibited higher in SMR and TMR. Furthermore, despite intelligence optimization algorithms significantly enhancing original ETo methods, the MDSL-GWA achieved best performance and outperformed other algorithms by 4.5–29.6% in determination coefficient (R2), 4.7–27.3% in nash-sutcliffe efficient (NSE), 3.7–44.4% in relative root mean square error (RRMSE), and 3.1–56.2% in mean absolute error (MAE), respectively. After optimization, the MDSL-GWA-PT was the most recommended ETo method in TMR, TCR, and MPR, and the median values of R2, NSE, RRMSE, and MAE ranged 0.907–0.958, 0.887–0.925, 0.083–0.103, and 0.115–0.162 mm, respectively. In SMR, the MDSL-GWA-HS produced the best ETo estimates, with median values of R2, NSE, RRMSE, and MAE being 0.876, 0.843, 0.112, and 0.146 mm, respectively. In summary, this study recommended the best ETo method and algorithms using accessible data in four climatic regions of China, which is helpful for decision-making in effective management and utilization of regional agricultural water resources.

Differences in functional niche hypervolume among four types of forest vegetation and their environmental determinants across various climatic regions in China.

Functional traits play an important role in studying the functional niche in plant communities. However, it remains unclear whether the functional niches of typical forest plant communities in different climatic regions based on functional traits are consistent. Here, we present data for 215 woody species, encompassing 11 functional traits related to three fundamental niche dimensions (leaf economy, mechanical support, and reproductive phenology). These data were collected from forests across four climatic zones in China (tropical, subtropical, warm-temperate, and cold-temperate) or sourced from the literature. We calculated the functional niche hypervolume, representing the range of changes in the multidimensional functional niche. This metric quantifies how many functional niche spaces are occupied by existing plants in the community. Subsequently, we analyzed differences in functional niche hypervolume and their associated environmental factors across different types of forest vegetation. The results indicate that the functional niche hypervolume and the degree of forest vegetation overlap decrease with increasing latitude (e.g., from tropical rainforest to cold temperate coniferous forest). The total explanatory power of both climate and soil factors on the variation in functional niche hypervolume was 50%, with climate factors exhibiting a higher explanatory power than soil factors. Functional niche hypervolume is positively correlated with climate factors (annual mean temperature and annual precipitation) and negatively correlated with soil factors (soil pH, soil organic matter content, soil total nitrogen content, and soil total phosphorus content). Among these factors, annual mean temperature, soil pH, and soil total nitrogen content most significantly affect the difference in functional niche hypervolume among forest vegetation. Our study emphasizes the significant variation in the functional niche hypervolume among typical forest vegetation in China.

Evaluation energy flow and analysis of energy economy for agricultural yield production in different geographical regions of China

Abstract Dry and humid climates have different potentials for providing soil moisture. Agricultural drought is a confirmed criterion for evaluating production potential in agriculture, which is discussed in this research. Therefore, this research aims to investigate drought using meteorological and agricultural drought indicator data in four climatic regions of China (humid, semi-humid, semi-arid and dry). For this purpose, climatic information was collected in the last 20 years, and the values of the standard precipitation index (SPI) and reconnaissance drought index (RDI) were determined. Examining the indicators indicates that the indicators are high in all the years under review in dry areas. In the semi-arid region, there was a significant decrease in the average value of the indices in July and August in the years 2017–2022. Drought indicators did not show a critical situation in humid and semi-humid areas, and there was sufficient moisture for plants throughout the year. The results showed that there was a high correlation between the SPI and the RDI in all the identified areas. In addition to rainfall, the RDI also includes transpiration and is more sensitive, especially in dry areas where transpiration is higher than rainfall.