Northward-shift of temperature zones in China’s eco-geographical study under future climate scenario

Hydrolases and oxidases regulate the decomposition of labile and recalcitrant soil organic matter， respectively， with their activities being highly sensitive to hydrothermal variations. Utilizing a cross-climatic zone soil translocation platform along China's North-South Transect， we transplanted in situ black soils from a cold temperate region （Hailun） to warm temperate （Fengqiu） and subtropical （Yingtan） zones， analyzing enzyme activity dynamics over a decade （from 2006 to 2015） through time-series analysis and structural equation modeling. Hydrolase activities exhibited a U-shaped temporal dynamic across three sites， most prominently in black soils from the warm temperate zone （Fengqiu） with an initial 25.71% decline （from 2006 to 2010） followed by a 151.32% surge by 2015. In contrast， oxidase activities experienced sustained suppression in black soils from the warm temperate zone， decreasing by 16.4% before stabilizing. These shifts drove a 125% elevation in the hydrolase-to-oxidase （H/O） ratio by 2015， indicating accelerated labile carbon turnover. The structural equation model revealed that hydrothermal variations indirectly regulated the H/O ratio through soil physicochemical factors： Black soils from the cold temperate zone were influenced by soil organic matter （β = -0.57） and total phosphorus （β = 0.32）， while black soils from the warm temperate zone were primarily constrained by pH reduction （β = 0.38） and amorphous aluminum oxides （β = 0.07）. Black soils from the subtropical zone displayed inhibition from organo-aluminum complexes （β = -0.42）. Under climate warming， rising H/O ratios may enhance labile carbon cycling， while mineral protection stabilizes recalcitrant carbon， collectively shaping the long-term carbon persistence of black soils.

Spring onset has generally shifted earlier in China over the past several decades in response to the warming climate. However, future changes in spring onset and false springs, which will have profound effects on ecosystems, are still not well understood. Here, we used the extended form of the Spring Indices model (SI-x) to project changes in the first leaf and first bloom dates, and predicted false springs for the historical (1950-2005) and future (2006-2100) periods based on the downscaled daily maximum/minimum temperatures under two emission scenarios from 21 General Circulation Models (GCMs) of the Coupled Model Intercomparison Project Phase 5 (CMIP5). On average, first leaf and first bloom in China were projected to occur 21 and 23days earlier, respectively, by the end of the twenty-first century in the Representative Concentration Pathway (RCP) 8.5 scenario. Areas with greater earlier shifts in spring onset were in the warm temperate zone, as well as the north and middle subtropical zones of China. Early false spring risk increased rapidly in the warm temperate and north subtropical zones, while that declined in the cold temperate zone. Relative to early false spring risk, late false spring risk showed a common increase with smaller magnitude in the RCP 8.5 scenario but might cause greater damage to ecosystems because plants tend to become more vulnerable to the later occurrence of a freeze event. We conclude that future climate warming will continue to cause earlier occurrence of spring onset in general, but might counterintuitively increase plant damage risk in natural and agricultural systems of the warm temperate and subtropical China.

In this study, eight extreme temperature event indices were calculated based on daily maximum, minimum, and mean temperature data recorded at 699 National Reference Stations in China during 1961–2020. The yearly change of mean temperature and the magnitude, frequency, and duration of extreme temperature events in six temperature zones were evaluated. All temperature zones had a trend of an increase in mean temperature (rate: 2.1–3.3 °C per 10 years), and the warming was more significant in the warm temperate zone and the Qinghai–Tibet Plateau zone (QPZ). For extreme temperature events, the extreme maximum and minimum temperatures in most temperature zones showed significant trends of increase, and the rates of increase were greater in the northern zones and QPZ. The rate of increase in extreme minimum temperature was substantially (up to three times) higher than the rate of increase in extreme maximum temperature in the same temperature zone; however, the finding was the opposite for the cold temperate zone (CTZ), which is the northernmost region of China. The rate of increase in extreme maximum temperatures was the greatest (0.35 °C per 10 years), whereas the rate of increase in extreme minimum temperatures was the smallest (0.17 °C per 10 years). The number of warm days/nights and the warm spell duration index also showed significant trends of increase that were most obvious in the southern zones and QPZ. In the tropical zone (TZ), which is the southernmost part of mainland China, the number of warm nights was only 15.3 days in 1961–1970, whereas it increased to 61.9 days in 2011–2020 (an increase of 303.9%). The rate of increase in warm nights in TZ (8.8 days per 10 years) was four times that in CTZ (2.2 days per 10 years). The number of cold days/nights and the cold spell duration index showed significant trends of decrease, with the greatest rates of reduction in QPZ and TZ. In evaluating the frequency of extreme temperature events, the amplitude of warming of the night index was found to be greater than that of the day index. In evaluating the duration of extreme temperature events, the variation of the cold index was found to be greater than that of the warm index. The notable asymmetries found in the variations of the minimum/maximum temperatures, day/night indices, and cold/warm spell durations in China are direct manifestations of global warming.

SYNOPSIS An analysis of the application of ground source heat pump (GSHP) systems to different temperature zones in China is presented in this paper. According to the climate characteristics, China is divided into six different temperature zones: the tropical zone, the subtropical zone, the warm temperate zone, the mid temperate zone, the cold temperate zone, and Qinghai-Tibet Plateau vertical temperature zone. Six representative cities corresponding to the six temperature zones are chosen and their different climate and soil characteristics are studied. The results show that a GSHP system can be applied to the first four temperature zones above, but not the cold temperate zone and the Qinghai-Tibet Plateau vertical temperature zone. However, in different temperature zones, different GSHP systems should be designed and built.

The Eastern Monsoon Region of China is sensitive to climate change because of its special location. In this study, the Automated Statistical Downscaling (ASD) tool was used to simulate and project future climate change scenarios in different temperate zones in the Eastern Monsoon Region of China. The performances of the single General Circulation Model (GCM) and the GCMs ensemble from Coupled Model Inter-comparison Project Phase 5 (CMIP5) were compared, and the capability of the ASD model was evaluated. The simple mathematical averaging ensemble of GCMs is superior to the single GCM and to the other two weighted ensembles. The ASD model was capable of presenting the temporal and spatial variation of four variables (precipitation, mean air temperature, maximum and minimum air temperature) during both the calibration and validation periods. The performance of the ASD model varied among the different temperate zones. In the simulated future scenarios, the air temperature in the four zones showed an upward trend. Except for the subtropical zone, there was a tendency for increased precipitation in both the warm temperate zone and the cold temperate and middle temperate zones. Of particular interest is that, in the subtropical zone, the precipitation will decline in the future, whereas the air temperature (especially the maximum air temperature) will increase, which may put more pressure on water resource situations in this area.

Comparative analyses of rotifer community structure in freshwater lakes among different climatic zones are limited. In this study, six freshwater lakes located in warm temperate, subtropical and tropical zones were selected to investigate the annual dynamics of rotifer communities and their major driving factors. The results indicated that rotifer community structure did not exhibit significant seasonal variations. However, significant differences were observed among climatic zones. The species number and total density of rotifers were significantly higher in subtropical lakes than in lakes from other zones (p < .05). Both multidimensional scaling and detrended correspondence analysis revealed significant separation of tropical samplings from warm temperate and subtropical samplings, which was mainly caused by the higher temperature and lower chlorophyll a content in the tropical lakes. Further analyses indicated that rotifer community structure was mainly affected by water temperature, trophic indices and pH in the warm temperate zone but by chlorophyll a content and Secchi depth in subtropical lakes. In addition, only the Simpson index was significantly associated with Secchi depth and pH in tropical lakes. Overall, these results indicated great differences in annual dynamics of rotifer communities and their driving factors among warm temperate, subtropical and tropical zones.

In primitively eusocial insects, air temperature is the environmental factor that primarily affects colony cycle. Several studies demonstrated interspecific differences in the adaptation of eusocial insects to local air temperature. Nevertheless, studies on intraspecific adaptations are rare. In this study, we investigate the influence of air temperature on local adaptations in behavior and colony productivity of Polistes biglumis foundresses living in warm and cold temperate zones. We hypothesized that foundresses from warm temperate zones would show a higher activity level compared to those from cold temperate zones before brood emergence, based on differences in air temperature between the two zones. After brood emergence, we expected a reduced foundress activity level in the warm climate zone, due to workers’ help. In contrast, foundresses living in the cold-climate zone, which do not produce workers, were expected to remain active throughout the nesting season. We also hypothesized that colony productivity was higher in warm-climate colonies. As expected, warm-climate foundresses reduced their activity level after brood emergence and, with their relatively large number of workers, continued egg production throughout the nesting season. Further studies are necessary to assess if these intraspecific differences are attributable to phenotypic plasticity or genetic divergence.

The air conditioning (AC) system of electric vehicles (EVs) consumes a large part of electricity of on-board batteries and influences the continue voyage course seriously. The feasibility of sorption type AC for EVs has been verified theoretically to decrease this part of energy consumption. However, the choice of optimal working pairs based on local working conditions is not considered before, which can realize not only high efficiency but also the steady and reliable operation. Thus in this paper, different solid sorption working pairs used in sorption type AC under different temperature zones are studied. We utilized Rubotherm balance test unit to study the sorption properties of various working pairs (halide-ammonia) and selected candidate working pairs by Clapeyron equation and energy analysis. Results show that MnCl2 is the only choice for cold temperate zone (CTZ) and CaCl2 is optimal for warm temperate zone (WTZ), while the mixed double halide (MnCl2 and CaCl2) is recommended in other zones. In middle temperate zone (MTZ), the probability for performance dropping down is relatively large, thus the ratio (CaCl2:MnCl2) is recommended as 0.33-1 to take advantage of the stability property of MnCl2. While in Qinghai-Tibet plateau cold area (QTPCA, the special temperature zone in China), the ratio is chosen as 2–3 because only under the limiting condition reaction [Ca(NH3)8]VCl2 ⇔ [Ca(NH3)4]Cl2+4NH3 is invalid. Because the continued high environmental temperature will increase the probability of limiting condition, ratio of subtropical zone (STZ) is still selected as 2–3 while that of tropical Zone (TZ) is 1–2. Taking WTZ under summer condition as example, by using sorption type AC with CaCl2 as sorbent, the increment voyage course (IVC) over the practical voyage course with conventional compression AC system (PVC) ranges from 9.4% to 37.7% for different type of EVs, i.e. the continue voyage course is increased effectively. This work provides the guidance for choosing optimal working pairs for actual utilization.

To determine the dividing index between warm temperate and subtropical zones based on the spectra of altitudinal belts, this paper collected 33 spectra of altitudinal belts in the Qinling-Daba Mountains from published literatures and then analyzed the structures and the spatial patterns from south to north, from west to east and based on exposure directions. The results show that: 1) From south to north, the basal belt gradually changes from subtropical evergreen broadleaf forest to warm temperate deciduous broadleaf forest; the spectra of altitudinal belts change from complex to simple; the dominant belt changes from montane broadleaf-conifer mixed forest and evergreen-deciduous broadleaf mixed forest to deciduous broadleaf forest. 2) From west to east, the structures of the altitudinal belt spectra show complexity in the east and west but simplicity in the middle section; the upper limits of both the evergreen-deciduous broadleaf mixed forest belt and montane deciduous broadleaf forest belt present a quadratic curve distribution pattern in the longitudinal direction. However, the upper limit of the montane broadleaf-conifer mixed forest belt exhibits a nearly linear decrease in the west-east direction. 3) Both the north and south slopes in the Qinling Mountains have the similar basal belt, whereas it varies greatly between the north and south slopes in the Daba Mountains. Comparably, dominant belts are very similar in the Qinling Mountains and the north slope of the Daba Mountains, but the south slope of the Daba Mountains has its own unique dominant belt: evergreen-deciduous broadleaf mixed forest. This implies that the Daba Mountains are more appropriate than the Qinling Mountains to act as the boundary between subtropical and warm-temperate zones in central China.

Snow depth is an important parameter to characterize the characteristics of snow cover, and it is also one of the most sensitive response factors to regional climate change. However, the extent of snow depth variability and its driving mechanisms are still unknown in China. Therefore, in this study, we used the regression analysis, root-mean-square error analysis, anomalous year analysis, and correlation analysis methods to explore the spatiotemporal variation characteristics of snow depth in China from 1979 to 2019 based on the reanalysis snow depth dataset. The results show that (1) the snow distribution in China is obviously spatially heterogeneous, and the southeastern, western, and southern regions of the Qinghai-Tibet Plateau, northern Xinjiang, and northeastern China have high values of snow depth; (2) the high-value regions are also the sensitive regions for anomalous variations in snow depth in China; (3) in the past 41years, the interannual variability of snow depth in China has shown a significantly decreasing trend, and the linear tendency of snow depth is - 0.093cm/10 a (p < 0.01) and the snow depth in four seasons showed a decreasing trend (p < 0.05); and (4) the driving factors of snow heterogeneity are dissimilar in different regions and seasons. In temperate zones, average air temperature is the main factor affecting snow depth in cold temperature, mid temperature, and warm temperature zones; the maximum air temperature is the main factor affecting snow depth in mid temperate and warm temperate zones. Both the minimum air temperature and the average land-surface temperature are important factors affecting the snow depth in the cold temperate, mid temperate and warm temperate zones, and all passed the significance test of 0.01.

Spatiotemporal variation of agroecosystem service trade-offs and its driving factors across different climate zones

The tilt angle with the horizon (with respect to the ground) of the solar energy system affects the amount of solar radiation received. This paper suggests a simple and universal method to obtain the optimum tilt angles by estimating the monthly mean daily global solar radiation on tilted surfaces facing directly towards the equator, which is based on monthly average daily global solar radiation data produced from Typical Meteorological Year (TMY) data. The monthly, seasonal, and yearly optimum tilt angles for photovoltaic panels are calculated at six stations of different climatic types (Tropical Zone (TZ), Subtropical Zone (SZ), Warm Temperate Zone (WTZ), Mid Temperate Zone (MTZ), Cold Temperate Zone (CTZ) and Tibetan Plateau Zone (TPZ)). The results indicate that changing the monthly, seasonal, and yearly optimum tilt angles causes a significant yearly gain in the solar radiation for the region. In addition, general correlations are generated to estimate the optimum tilt angle of solar collectors at six typical climatic stations of China. The performances of the proposed models are compared using statistical error tests such as the mean absolute bias error (MABE), the root mean square error (RMSE) and the correlation coefficients (R).

Since a representative dataset of the climatological features of a location is important for calculations relating to many fields, such as solar energy system, agriculture, meteorology and architecture, there is a need to investigate the methodology for generating a typical meteorological year (TMY). In this paper, a hybrid method with mixed treatment of selected results from the Danish method, the Festa-Ratto method, and the modified typical meteorological year method is proposed to determine typical meteorological years for 35 locations in six different climatic zones of China (Tropical Zone, Subtropical Zone, Warm Temperate Zone, Mid Temperate Zone, Cold Temperate Zone and Tibetan Plateau Zone). Measured weather data (air dry-bulb temperature, air relative humidity, wind speed, pressure, sunshine duration and global solar radiation), which cover the period of 1994–2015, are obtained and applied in the process of forming TMY. The TMY data and typical solar radiation data are investigated and analyzed in this study. It is found that the results of the hybrid method have better performance in terms of the long-term average measured data during the year than the other investigated methods. Moreover, the Gaussian process regression (GPR) model is recommended to forecast the monthly mean solar radiation using the last 22 years (1994–2015) of measured data.

A variety of computer-based simulation programs to calculate the energetic behaviour of houses and the use of renewable energies are available. However, these are developed for the detailed design of building physics or engineering design of heating- and solar systems. In many cases, these programs require detailed knowledge and licenses are expensive. A zero or plus energy house in many cases, is a continuation of the Passive House. For this purpose, space and resources need to be provided and the building structure needs to be adjusted. These considerations have to be taken into account early in the building design. The aim of this current study was to develop a concept for an Energy Toolbox. It aims to be a widely-accessible easy-to-use tool to designing Zero Emission Buildings (ZEB) and is based on Microsoft Excel. The building structure design is introduced in the first part of the Energy Toolbox and takes common basic elements in building physics into account. This part determines energy demand for heating and cooling and meets Passive House criteria. In addition, the electrical demand for light and facilities is evaluated in this first part. Climatic parameters are taken into account for calculations of heat transfer coefficient, heat gains and ventilation losses. The calculation tool is designed for three different climates: Sub oceanic cool temperate zone, central Europe, warm temperate sub-tropical zone with Mediterranean wet winters and dry summers, Turkey, and a cold temperate zone with warm, humid summers, South Korea. In those zones, Zurich, Berlin, Istanbul and Seoul have been studied. Necessary climate parameters for solar-radiation, heating and cooling degree days, base temperature and other relevant temperatures for building calculation have been set. Those have a profound influence on the energy needs for heating and cooling. The second part of the Energy Toolbox determines technologies that could be used to cover the energy demand of buildings. These include heat pump systems with different heating and cooling sources (geothermal, outside air and waste water), solar (thermal and photovoltaic) as well as the adiabatic cooling. In addition, technologies and methods that contribute to a reduced energy demand are presented. Green walled buildings, adaptable dynamic lighting and shading devices provide this solution. A possible combination employs three main systems. An air-water heat pump compact system, a brine/ water heat pump system with sewage or geothermal utilization and a solar-thermal system with seasonal storage. All three systems can be supplemented with solar energy and designed in terms of a net zero balance. The energy consumption of the building corresponds to the concept of zero-plus-energy buildings. The second part of the Energy Toolbox is has been described schematically. It is designed such that it can be supplemented with additional technologies in the future.

During 2001, a series of four site–taxa interaction trials was established in the warm temperate (mean annual temperature range 16–19 °C) forestry climatic zone of KwaZulu-Natal (KZN), South Africa. The main objective was to investigate the commercial forestry potential of a range of alternative Eucalyptus and Corymbia taxa for moderately dry (mean annual precipitation < 850 mm) sites within the zone. At rotation end, all trials received final standing tree measurements. At one of the sites (Rockvale), trees of eight promising alternative taxa were felled, stem measurements and wood samples taken, and wood and fibre productivities determined. On the basis of tree growth and wood and fibre production, C. citriodora subsp. variegata, C. henryi, E. badjensis, E. benthamii and E. dorrigoensis (listed alphabetically) demonstrated the greatest potential as commercial alternatives for moderately dry sites in the KZN warm temperate zone. The majority of these taxa showed strong site specificity. Eucalyptus benthamii was the only taxon showing high growth adaptability to the entire range of site conditions applied in the series. The non-susceptibility of C. citriodora subsp. variegata and C. henryi to the current topical insect pests Thaumastocoris peregrinus, Leptocybe invasa and Glycaspis brimblecombei elevates the appeal of these taxa as potential alternative planting choices for moderately dry sites within lower altitude (<1 100 m asl) areas of the climate zone. The matching of the most promising alternative taxa in the series to the range of sites encountered in moderately dry areas of the KZN warm temperate forestry zone is discussed in this paper.