Winter Region Research Articles

Spatio–Temporal Variation of Vapor Pressure Deficit and Impact Factors in China in the Past 40 Years

Vapor pressure deficit (VPD) is critical to the carbon–water cycle of an ecosystem, which is widely used in various hydrological cycles, vegetation carbon cycles, and evapotranspiration-estimation models. However, few studies on VPD have been conducted. Most regions of China are experiencing accelerated urbanization and continuing increased interannual variations in atmospheric parameters, such as temperature and humidity. An in-depth study on the variation and dominant factors of VPD in different seasons and climate regions will provide a scientific basis for the study of climate, ecology, and vegetation models. Such a study will also help improve environmental management in different climate regions to achieve ecologically sustainable development. Based on the monthly meteorological observation data of more than 600 stations in China, combined with the Mann–Kendall test, multiple linear regression, and other methods, this study analyzed the spatio–temporal variation pattern of VPD in the four climate regions (i.e., arid, humid, semiarid, and subhumid) of China from 1980 to 2018 to detect the dominant meteorological factors affecting the variation of VPD. The results showed that for the last 40 years, the distribution of VPD in Chinahadd spatial and seasonal differences. For all four climate regions, VPD had the characteristics of “summer > spring > autumn > winter.” The distribution of VPD in summer and winter is opposite in the humid and arid regions of China. That is, the VPD in spring and summer gradually increased from the humid region to the arid region; whereas, it gradually decreased from the humid region to the arid region in winter. VPD exhibited an upward trend in most areas of China in the four seasons, particularly in the Yellow River Basin and southeast coastal areas in spring and summer. Moreover, the VPD of the four climate regions increased abruptly in the early 21st century. Among them, the humid region had an earlier mutation year (1996), and the arid region had a later mutation year (2004); the increase in the arid region was the highest, at approximately 0.04 kPa/10 a). These phenomena indicate that the atmosphere has become drier, and to determine the cause of this phenomenon, we analyzed the contribution rate of meteorological factors to VPD. The results showed that the dominant factors affecting the increase in VPD are different in different climate regions and seasons, but overall, changes in air temperature and absolute humidity are the main factors affecting the interannual change of VPD in China. After 2000, the dominant factors affecting VPD in subhumid and semiarid and other areas are temperature and absolute humidity, respectively.

Objective Synoptic Weather Classification on Air Pollution during Winter Seasons in Hangzhou

Using the 2015-2018 Hangzhou city PM2.5, PM10, SO2, CO, NO2 and O3 mass concentration data, ERA5 reanalysis data and ground observation data, through the PCT classification method, the objective analysis of the winter air pollution weather situation in Hangzhou was obtained. The results showed that the winter air quality concentration in Hangzhou continued to be high from 2015 to 2018, and the air pollution was the most significant. Through objective classification, it is concluded that the main weather conditions affecting the region in winter are divided into 6 types, namely high pressure control, high pressure bottom control equalizing field, L-shaped high pressure control, high pressure front control equalizing field, low pressure control, low pressure front control Equalizing field. Among them, when high pressure control, high pressure bottom control equalizing field, L high pressure control, low pressure control are affected by local sources, the impact of external sources has a greater impact on the air quality in Hangzhou, and air pollution is prone to occur; before low pressure When the pressure equalization field is controlled by the Ministry and the pressure equalization field is controlled by the high pressure front, the local wind and precipitation in Hangzhou are relatively high, which is not conducive to the accumulation of air pollutants. The probability of occurrence of air pollution is small, and air pollution is not easy to occur.

Сезонные особенности функциональной активности эндокринных систем у жителей гор

The article presents the results of studies of changes in the functional state of the endocrine systems of high-altitude residents, depending on the periods of the year that are associated with the ambient temperature, with the daylight regime and other factors. High altitude regions are distinguished by a severely continental climate, which is characterized by large temperature and barometric differences between the winter and summer months, expressed by the seasons of the year. The object of research was the indigenous people of the mountains, living at an altitude of 2800 m above sea level, from 18–55 years old. The level of thyroid hormones, TSH, cortisol, catecholamines and sex hormones in peripheral blood plasma was determined by the method of enzyme-linked immunosorbent assay using standard test kits (Russia). It was found that in high-altitude conditions there is a seasonal variability in the functional activity of the pituitary-thyroid system in healthy men leads to an increase in metabolism, since rhythmic changes in the secretion of thyroid hormones and biochemical parameters are interrelated. So, in winter, the level of triiodothyronine is increased with a slight change towards a decrease in thyroxine and thyroid-stimulating hormone of the adenohypophysis compared with the summer months. At the same time, the above studies did not reveal a clear relationship between the functional state of the thyroid gland and atmospheric pressure and ambient temperature. Norepinephrine and dopamine levels rise significantly in winter, with a slight decrease in other neurotransmitters, adrenaline and serotonin. In the studied mountainous region in winter, the ambient temperature is significantly lower than in summer, and has an additional effect on the functional state of the endocrine systems after hypoxia. Compensatory-adaptive changes when exposed to low temperature of the environment are triggered with the participation of catecholamines, which, by breaking down fats and carbohydrates, mobilize energy reserves, increase heat production and constrict the vessels of the body surface. Interacting with catecholamines, thyroid hormones activate metabolic processes, also increase heat generation, affecting the processes of oxidative phosphorylation, enhance the “calorigenic” effect of catecholamines, and also activate the secretion of ACTH and glucocorticosteroids. Fluctuations in the level of the studied hormones in the peripheral blood in the indigenous population of the highlands are subject to changes not only in the seasons of the year, but also in the duration of daylight hours. To date, there are data (including those obtained experimentally) that show the effect of light on the release of sex hormones and cortisol in humans, which indicate changes in the secretion of these hormones during the year, associated with a change in the length of daylight hours.

A general method to evaluate the applicability of natural energy for building cooling and heating: Revised degree hours

Utilizing natural energy directly for building cooling and heating can reduce the energy use of the HVAC systems significantly. There are various utilization forms of natural energies for building cooling and heating. The applicability of natural ventilation was evaluated in the previous studies by degree hours method which cannot be used for the evaluation of other natural energy utilizing forms. To provide guidance for selecting proper natural energy and the utilizing forms for building cooling and heating, a general method, i.e., the revised degree hours method, is proposed. Firstly, the conception and rationality of the revised degree hours method are indicated by comparing with the degree hours method. Then, the utilizations of revised degree hours method in evaluating the applicability of natural energy are discussed in terms of different climates, different natural energies and different utilizing forms. The results show that the revised degree hours can directly reflect the energy saving potential of natural energy and it is capable of fairly evaluating different utilization forms with different kinds of natural energies. According to these cases analyzed in this paper, the mechanical ventilation shows a quite promising potential in the temperate region; both the dew point evaporative cooling and the ground heat exchanger fresh air handling system are outstanding in the dry and cold region; the cooling tower combined with pipe-embedded window system works well in the hot summer and cold winter region as well as the hot summer and warm winter region. In conclusion, the revised degree hours method contributes to the low carbon development of HVAC systems by guiding the full use of natural energy for building energy efficiency.

Long-Term Lime and Phosphogypsum Amended-Soils Alleviates the Field Drought Effects on Carbon and Antioxidative Metabolism of Maize by Improving Soil Fertility and Root Growth.

Long-term surface application of lime (L) and/or phosphogypsum (PG) in no-till (NT) systems can improve plant growth and physiological and biochemical processes. Although numerous studies have examined the effects of L on biomass and plant growth, comprehensive evaluations of the effects of this practice on net CO2 assimilation, antioxidant enzyme activities and sucrose synthesis are lacking. Accordingly, this study examined the effects of long-term surface applications of L and PG on soil fertility and the resulting impacts on root growth, plant nutrition, photosynthesis, carbon and antioxidant metabolism, and grain yield (GY) of maize established in a dry winter region. At the study site, the last soil amendment occurred in 2016, with the following four treatments: control (no soil amendments), L (13 Mg ha–1), PG (10 Mg ha–1), and L and PG combined (LPG). The long-term effects of surface liming included reduced soil acidity and increased the availability of P, Ca2+, and Mg2+ throughout the soil profile. Combining L with PG strengthened these effects and also increased SO42–-S. Amendment with LPG increased root development at greater depths and improved maize plant nutrition. These combined effects increased the concentrations of photosynthetic pigments and gas exchange even under low water availability. Furthermore, the activities of Rubisco, sucrose synthase and antioxidative enzymes were improved, thereby reducing oxidative stress. These improvements in the physiological performance of maize plants led to higher GY. Overall, the findings support combining soil amendments as an important strategy to increase soil fertility and ensure crop yield in regions where periods of drought occur during the cultivation cycle.

A comparative study of EOF and NMF analysis on downward trend of AOD over China from 2011 to 2019

In recent decades China has experienced high-level PM2.5 pollution and then visible air quality improvement. To understand the air quality change from the perspective of aerosol optical depth (AOD), we adopted two statistical methods of Empirical Orthogonal Functions (EOF) and Non-negative Matrix Factorization (NMF) to AOD retrieved by MODIS over China and surrounding areas. Results showed that EOF and NMF identified the important factors influencing AOD over China from different angles: natural dusts controlled the seasonal variation with contribution of 42.4%, and anthropogenic emissions have larger contribution to AOD magnitude. To better observe the interannual variation of different sources, we removed seasonal cycles from original data and conducted EOF analysis on AOD monthly anomalies. Results showed that aerosols from anthropogenic sources had the greatest contribution (27%) to AOD anomaly variation and took an obvious downward trend, and natural dust was the second largest contributor with contribution of 17%. In the areas surrounding China, the eastward aerosol transport due to prevailing westerlies in spring significantly influenced the AOD variation over West Pacific with the largest contribution of 21%, whereas the aerosol transport from BTH region in winter had relative greater impact on the AOD magnitude. After removing seasonal cycles, biomass burning in South Asia became the most important influencing factor on AOD anomalies with contribution of 10%, as its interannual variability was largely affected by El Niño. Aerosol transport from BTH was the second largest contributor with contribution of 8% and showed a decreasing trend. This study showed that the downward trend of AOD over China since 2011 was dominated by aerosols from anthropogenic sources, which in a way confirmed the effectiveness of air pollution control policies.

Temperate Fruit Trees under Climate Change: Challenges for Dormancy and Chilling Requirements in Warm Winter Regions

Adequate chill is of great importance for successful production of deciduous fruit trees. However, temperate fruit trees grown under tropical and subtropical regions may face insufficient winter chill, which has a crucial role in dormancy and productivity. The objective of this review is to discuss the challenges for dormancy and chilling requirements of temperate fruit trees, especially in warm winter regions, under climate change conditions. After defining climate change and dormancy, the effects of climate change on various parameters of temperate fruit trees are described. Then, dormancy breaking chemicals and organic compounds, as well as some aspects of the mechanism of dormancy breaking, are demonstrated. After this, the relationships between dormancy and chilling requirements are delineated and challenging aspects of chilling requirements in climate change conditions and in warm winter environments are demonstrated. Experts have sought to develop models for estimating chilling requirements and dormancy breaking in order to improve the adaption of temperate fruit trees under tropical and subtropical environments. Some of these models and their uses are described in the final section of this review. In conclusion, global warming has led to chill deficit during winter, which may become a limiting factor in the near future for the growth of temperate fruit trees in the tropics and subtropics. With the increasing rate of climate change, improvements in some managing tools (e.g., discovering new, more effective dormancy breaking organic compounds; breeding new, climate-smart cultivars in order to solve problems associated with dormancy and chilling requirements; and improving dormancy and chilling forecasting models) have the potential to solve the challenges of dormancy and chilling requirements for temperate fruit tree production in warm winter fruit tree growing regions.

A new retrofitting strategy for the improvement of indoor environment quality and energy efficiency in residential buildings in temperate climate using prefabricated elements

The renovation of existing residential buildings across Europe has become a key factor for energy saving and the improvement of Indoor Environment Quality (IEQ). This paper presents an investigation of IEQ for a typical 1960s single-family house in Germany before and after a new retrofitting strategy (prefabricated element with integrated ventilation and new thermal envelope). In-situ measurements were applied to investigate the energy efficiency and IEQ improvement for the new retrofitting strategy in temperate winter regions of Europe. The simulation model replicates the measured data to be closer to reality and simulates a home office (COVID-19) scenario. The in-situ measurements showed that our retrofitting strategy increases the indoor air temperature during the heating period by up to 2.5 °C, decreases relative humidity by up to 3.8% and increases CO2 by up to 24 ppm than before. As the simulation results shows, the retrofitted home office scenario allows a reduction in heating energy of up to 77%, an increase in CO2 concentration of up to 41.8 ppm, 0.5% less relative humidity and 1.6 °C higher indoor air temperature than that without retrofitting. The new approach to retrofit residential buildings thus showed a potential in energy saving and improving the IEQ.

Impact of Atmospheric Deposition on Carbon Export to the Deep Ocean in the Subtropical Northwest Pacific

AbstractThe impact of atmospheric deposition on deep‐ocean carbon export in the subtropical Northwest Pacific remains poorly evaluated. Using sediment trap data and a newly improved biogeochemical model, we show that iron deposition in winter and spring and nitrogen deposition in summer and fall are important drivers for the seasonal variability of deep‐ocean particulate organic carbon (POC) export flux. Nitrogen deposition can stimulate pico‐plankton growth in summer and fall, which leads to increases of microzooplankton and mesozooplankton. The increase of mesozooplankton exerts higher grazing pressure on diatoms in winter and early spring, which then reduces deep‐ocean POC export due to the reduction of ballasting mineral of opal. Iron deposition only affects the region in winter and spring when nitrogen is not a limiting factor for phytoplankton growth; and it can increase deep‐ocean POC export by stimulating diatom growth and opal production.

High-chilling requirement apple cultivar has more accentuated acrotony than low-chilling one in mild winter region

High-chilling requirement apple cultivar has more accentuated acrotony than low-chilling one in mild winter region

Smart solution for low humidity problems using automatic ultrasonic humidifier (AUH)

Humidity has a substantial impact on biological and environmental factors. Improper relative humidity (too high or very low) can create discomfort for individuals and affect several systems and apparatus. On the other hand, the correct type of humidifying machinery and functions may facilitate reliable, economic, and trouble-free control of moisture. Humidity in the winter region is always too low, which causes anxiety. This study aims to develop a microcontroller-based system to identify and eliminate such low humidity problems. A control system is implemented to generate air humidity according to the need to decide whether the unit is working. A wireless sensor was used to measure the room’s relative humidity and temperature. The Humidifier is activated whenever the relative humidity is less than that of the setting’s value according to the standard humidity value. A humidifier is developed using vaporizing ultrasound, which can still be considered the automatic ultrasonic Humidifier (AUH). The setting is suitable in the winter zone or where the relative humidity is below the standard comfort value. In this study, data were recorded in Khulna, Bangladesh, between April and May of 2018. Most of the sensor’s recorded values were greater than the standard comfort Relative humidity, so the Humidifier was disabled. Humidifier activated while the sensor recorded lower relative humidity value with comparison to the standard set value.

Separating the Indian and Pacific Ocean Impacts on the Euro-Atlantic Response to ENSO and Its Transition from Early to Late Winter

AbstractThe present study focuses on the mechanism that controls the transition of the Euro-Atlantic circulation responses to El Niño–Southern Oscillation (ENSO) from early (December) to late winter (February) for the period 1981–2015. A positive phase of ENSO induces a precipitation dipole with increased precipitation in the western and reduced precipitation in the eastern tropical Indian Ocean; this occurs mainly during early winter (December) and less so in late winter (February). It is shown that these interbasin atmospheric teleconnections dominate the response in the Euro-Atlantic sector in early winter by modifying the subtropical South Asian jet (SAJET) and forcing a wavenumber-3 response that projects spatially onto the positive North Atlantic Oscillation (NAO) pattern. On the contrary, during late winter, the response in the Euro-Atlantic sector is dominated by the well-known ENSO wave train from the tropical Pacific region, involving extratropical anomalies that project spatially on the positive phase of the Pacific–North American (PNA) pattern and the negative phase of the NAO pattern. Numerical experiments with an atmospheric model (an AGCM) forced by an Indian Ocean heating dipole anomaly support the hypothesis that the Indian Ocean modulates the SAJET and enforces the Rossby wave propagation to the Euro-Atlantic region in early winter. These phenomena are also investigated using the ECMWF SEAS5 reforecast dataset. In SEAS5, the ENSO interbasin tropical teleconnections and the response of the Euro-Atlantic circulation anomalies and their change from early to late winter are realistically predicted, although the strength of the early winter signal originated from the Indian Ocean is underestimated.

The Role of an Indian Ocean Heating Dipole in the ENSO Teleconnection to the North Atlantic European Region in Early Winter during the Twentieth Century in Reanalysis and CMIP5 Simulations

AbstractIn this study the role of an Indian Ocean heating dipole anomaly in the transition of the North Atlantic–European (NAE) circulation response to El Niño–Southern Oscillation (ENSO) from early to late winter is analyzed using a twentieth-century reanalysis and simulations from phase 5 of the Coupled Model Intercomparison Project (CMIP5). It is shown that in early winter a warm (cold) ENSO event is connected through an atmospheric bridge with positive (negative) rainfall anomalies in the western Indian Ocean and negative (positive) anomalies in the eastern Indian Ocean. The early winter heating dipole, forced by a warm (cold) ENSO event, can set up a wave train emanating from the subtropical South Asian jet region that reaches the North Atlantic and leads to a response that spatially projects onto the positive (negative) phase of the North Atlantic Oscillation. The Indian Ocean heating dipole is partly forced as an atmospheric teleconnection by ENSO, but can also exist independently and is not strongly related to local Indian Ocean sea surface temperature (SST) forcing. The Indian Ocean heating dipole response to ENSO is much weaker in late winter (i.e., February and March) and not able to force significant signals in the North Atlantic region. CMIP5 multimodel ensemble reproduces the early winter Indian Ocean heating dipole response to ENSO and its transition in the North Atlantic region to some extent, but with weaker amplitude. Generally, models that have a strong early winter ENSO response in the subtropical South Asian jet region along with tropical Indian Ocean heating dipole also reproduce the North Atlantic response.

Heat transfer characteristics of gravelly soils with different compactness during unidirectional freezing process

During the construction of clay core rockfill dam in cold regions in winter, the heat transfer characteristics of gravelly soil are important to the anti-freezing control of the core. Laboratory experiment and field test data showed that the frost depth of gravelly soil in unconsolidated state was deeper than that in compacted state at the early period of soil freezing. With the increase of the freezing time, however, the frost depth of compacted soil is deeper than that of unconsolidated soil. Further study showed that this phenomenon was main caused by the change of thermophysical parameters between unconsolidated and compacted soil. Under the same soil temperature, the thermal conductivity of compacted soil was approximately 2.6 times of that of unconsolidated soil, and the volume heat capacity and phase change latent heat of compacted soil was approximately 1.7 times of that of unconsolidated soil. The different thermophysical parameters caused the differences of the heat transfer rate, temperature distribution and heat release by cooling between compacted soil and unconsolidated soil. This study provides a theoretical guidance for freezing process of soil with different compactness and anti-freezing technology of clay core rockfill dam in cold regions.

Winter fidelity, movements, and energy expenditure of Midcontinent Greater White-fronted Geese

BackgroundAnimal movement patterns are the result of both environmental and physiological effects, and the rates of movement and energy expenditure of given movement strategies are influenced by the physical environment an animal inhabits. Greater white-fronted geese in North America winter in ecologically distinct regions and have undergone a large-scale shift in wintering distribution over the past 20 years. White-fronts continue to winter in historical wintering areas in addition to contemporary areas, but the rates of movement among regions, and energetic consequences of those decisions, are unknown. Additionally, linkages between wintering and breeding regions are generally unknown, and may influence within-winter movement rates.MethodsWe used Global Positioning System and acceleration data from 97 white-fronts during two winters to elucidate movement characteristics, model regional transition probabilities using a multistate model in a Bayesian framework, estimate regional energy expenditure, and determine behavior time-allocation influences on energy expenditure using overall dynamic body acceleration and linear mixed-effects models. We assess the linkages between wintering and breeding regions by evaluating the winter distributions for each breeding region.ResultsWhite-fronts exhibited greater daily movement early in the winter period, and decreased movements as winter progressed. Transition probabilities were greatest towards contemporary winter regions and away from historical wintering regions. Energy expenditure was up to 55% greater, and white-fronts spent more time feeding and flying, in contemporary wintering regions compared to historical regions. White-fronts subsequently summered across their entire previously known breeding distribution, indicating substantial mixing of individuals of varying breeding provenance during winter.ConclusionsWhite-fronts revealed extreme plasticity in their wintering strategy, including high immigration probability to contemporary wintering regions, high emigration from historical wintering regions, and high regional fidelity to western regions, but frequent movements among eastern regions. Given that movements of white-fronts trended toward contemporary wintering regions, we anticipate that a wintering distribution shift eastward will continue. Unexpectedly, greater energy expenditure in contemporary wintering regions revealed variable energetic consequences of choice in wintering region and shifting distribution. Because geese spent more time feeding in contemporary regions than historical regions, increased energy expenditure is likely balanced by increased energy acquisition in contemporary wintering areas.

Impacts of dynamic and thermal forcing by the Tibetan Plateau on the precipitation distribution in the Asian arid and monsoon regions

The dynamic and thermal effects of the Tibetan Plateau (TP) on the precipitation in the Asian arid and monsoon regions were investigated using three numerical experiments—one using real topography, one with the whole TP removed, and one with sensible heat turned off over the TP. The results show that there are strong seasonal and regional differences in the dynamic and thermal effects of the TP on the precipitation in the Asian arid regions. The dynamic effect dominated the decrease in winter precipitation by blocking the westerly, while the thermal effect dominated the decrease in summer precipitation due to the TP-induced compensation downdraft in Central Asia and arid East Asia. The thermal effect dominated and accounted for 60% of the decrease in summer precipitation in West Asia. The results also show that both the dynamic and thermal effects of TP exhibit a more salient influence on the East Asian monsoon region than the South Asian monsoon region. The thermal effect dominated and accounted for 40% of the increase in summer precipitation due to intensification of the summer monsoon, while the dynamic effect dominated and accounted for 80% of the decrease in winter precipitation due to the northeast wind anomaly in the northern East Asian monsoon region. The anomalous wind can reach to the coast of South China and form frontal precipitation in the southern East Asian monsoon region in winter. The thermal effect dominated and accounted for 80% of the increase in precipitation in the pre-monsoon period due to intensification of the Asian summer monsoon.

A study on heating of residential buildings in the Yangtze River Valley of China

Yangtze River is China's densely populated and the most economically prosperous region. It’s hot and humid in summer and cold in winter in this region. This area is considered as a non-heating region in winter, The residential building design usually does not consider the building heating requirements. The building envelope thermal performance is poor, and the indoor thermal environment quality is worse in the residential building in this region. In recent years, local experts and residents in the area have expressed strong willingness to building heating in winter. Consequently, on the basis of field investigation and field test, this paper has analyzed the choice of building heating mode from the aspects of local meteorological conditions, indoor environment status, local residents' living habits and residents' heating demand. Based on the results of the technological economic comparison of preliminary studies, suggestions on the suitable building heating mode were given in the Yangtze River Valley of China.

ARIDIZATION OF THE CLIMATE OF THE ROSTOV REGION

The combination of natural and anthropogenic factors contributes to the development of aridization process and its consequences in the Rostov region. The article discusses the dynamics of climatic conditions affecting the aridization of the region. Changes of in the global and regional climate contribute to intensification of aridization process. Particular attention is paid to long-term changes in the amount of precipitation at the hydrometeorological stations Taganrog, Rostov-on-Don, Gigant and Remontnoe (by years and seasons), as well as dust storm. The observation data analysis revealed slight increase in the yearly precipitation from the beginning of the twentieth to the beginning of the twenty-first centuries for all meteorological stations under consideration (the most of all in the west of the Rostov region). At the same time, a slight decrease in the yearly precipitation in the last decade is noted, which caused a low-flow period in the Lower Don. Seasonal changes in precipitation regime are pronounced. A decrease in the amount of summer precipitation is noted at all stations (especially in the east of the region). At the same time, an increase in the amount of precipitation is observed in the west of the region in winter. Frequency and duration of dust storm decreases from east to west in the Rostov region. The least amount of the dust storm was noted in Taganrog, and the most of all in Remontnoe. Over the past 20 years, the duration and frequency of dust storm have increased at the meteorological station Gigant and decreased at the meteorological station Remontnoe. The changes are not significant for other meteorological stations. The peak values of the duration of dust storms at the meteorological stations are noted in 1969 (Taganrog), 1984 (Remontnoe), 1995 (Rostov-on-Don), 2014 (Gigant).

The effect of biogas fermentation assisted by simple solar greenhouse

Biogas fermentation rate is largely affected by environment temperature, causing a much more difficult production of biogas digesters in cold winter, for most regions in China. Combining the abundant solar energy resources and biomass dry anaerobic fermentation together, solar thermal energy can guarantee the production of biogas in winter. With this method, the prediction of the appropriate fermentation temperature is required. In this study, the effect of temperature on biogas fermentation was studied. To predict the fermentation temperature, a heat transfer model of biogas fermentation based on a project in city Xuzhou, which assisted with a simple solar greenhouse, was established according to the heat transfer theory. The maximum difference between the measured and calculated fermentation temperature was 2%. The effect of biogas fermentation assisted by simple solar greenhouse in typical city of different climate zones, including severe cold region, cold region and hot summer and cold winter region, was studied with the combination of heat transfer model and temperature-based biogas production rates prediction model. The results showed that, the gas production rate of biogas fermentation increases with the increase of temperature in a certain range. Assisted by simple solar greenhouse, the biogas digester temperature is increased by 6~8°C compared with the previous one, ensuring a better daily gas production rate of 0.5~0.7m3/m3 in winter.

Temperature Influence on the Date of Flowering of Apple Trees Grown in Mild Winter Region in Brazil Based on Long-Time of Phenology Records

Temperature Influence on the Date of Flowering of Apple Trees Grown in Mild Winter Region in Brazil Based on Long-Time of Phenology Records