揭/盖保温被时间对日光温室气温的影响

为廊坊市及类似地区日光温室油桃和毛桃揭、盖保温被时间提供借鉴参考,利用河北省廊坊市2017年1-4月2个不同日光温室的连续观测数据,研究不同揭、盖保温被时间对日光温室气温的影响。结果表明:多云、阴天和晴天3种天气条件下不同揭、盖保温被时间的总体变化趋势一致;随着时间的推后,揭保温被的时间越来越早,盖保温被时间则越来越晚;连阴天第2天后应推迟揭保温被时间,提早盖保温被时间,第3天后揭保温被时间应推迟至10∶00后;揭保温被时间过早,1月晴天和多云天白天不能满足温室桃对温度的需求,2月晴天和多云天基本能满足温室桃对温度的要求,但阴天应推迟揭保温被的时间并提早覆盖保温被。

不同天气下冬季温室气温的变化特征

结果表明：在不同天气下,棚内气温均存在日变化,晴天条件下均从8：00开始迅速升温;多云-少云天气下,12-2月份升温时间明显不同,分别为10：00、9：00和8：00;晴天和多云-少云天气下,到达气温峰值时间一致,1月份棚内气温在14：00达最高值;12月和2月在13：00达最高值,寡照天气下气温升温缓慢,升温幅度较小,仅为同月份晴天时升温幅度的16%-48%,达到峰值时间与晴天和寡照天气下达峰值时间不同。不同天气下温室内日最高气温表现为晴天〉多云-少云〉寡照,日最低表现为晴天〈多云-少云〈寡照。

Soil carbon dioxide fluxes of a typical broad-leaved/Korean pine mixed forest in Changbai Mountain, China

The forest ecosystem plays an important role in the global carbon cycling. A study was conducted to evaluate soil CO2 flux and its seasonal and diurnal variation with the air and soil temperatures by using static closed chamber technique in a typical broad-leaved/Korean pine mixed forest area on the northern slope of Changbai Mountain, Jilin Province, China. The experiment was carried out through the day and night in the growing season (from June to September) in situ and sample gas was analyzed by a gas chromatograph. Results showed that the forest floor was a large net source of carbon, and soil CO2 fluxes had an obvi-ous law of seasonal and diel variation. The soil CO2 flux of broad-leaved/Korean pine mixed forest was in the range of 0.302.42 mmol穖-2穝-1 with the mean value of 0.98 mmol穖-2穝-1. An examination on the seasonal pattern of soil CO2 emission suggested that the variability in soil CO2 flux could be correlated with variations in soil temperature, and the maximum of mean CO2 flux occurred in July ((1.27±23%) mmol穖-2穝-1) and the minimum was in September ((0.50±28%) mmol穖-2穝-1). The fluctuations in diel soil CO2 flux were also correlated with changes in soil temperature; however, there existed a factor for a time lag. Soil CO2 flux from the forest floor was strongly related to soil temperature and had the highest correlation with temperature at 6-cm depth of soil. Q10 values based on air temperature and soil temperature of different soil depths were at the ranges of 2.09–3.40.

A STUDY ON THE CHARACTERISTICS OF INTERNAL ANDEXTERNAL WALL SURFACE TEMPERATUREIN THE URBAN AREA

Internal and external wall surface temperatures (Tws) in April, August and December in Kunming, a city in low latitude plateau, were investigated. Results showed that the Tws in April were of the highest among the three, followed by August and December. The Tws differences among walls with different orientation were higher in April and December when the weather tends to be sunny, and lower in August with more cloudy days in the time. In April and August, Tws of E-wall was the highest, followed by S- and N-wall. But in December Tws of S-wall might be sometimes higher than E one. Diurnal range of internal Tws was usually smaller than that of the external, with also a time lag for the occurrence of its maximum and minimum. The results can serve as a basis for further research on building microclimate and urban architecture designs. It also gives suggestions for similar studies in other areas.

Effects of Nitrogen Fertilizer,Soil Moisture and Temperature on Methane Oxidation in Paddy Soil

Effects of nitrogen fertilizer,soil moisture and temperature on methane oxidation in paddy soil were investigated under laboratory conditions. Addition of 0.05 g N kg-1 soil as NH4Cl strongly inhibited methane oxidation and addition of the same rate of KCl also inhibited the oxidation but with more slight effect,suggesting that the inhibitory effect was partly caused by increase in osmotic potential in microorganism cell.Not only NH but also NO greatly affected methane oxidation.Urea did not affect methane oxidation in paddy soil in the first two days of incubation,but strong inhibitory effect was observed afterwards.Methane was oxidized in the treated soil with an optimum moisture of 280 g kg-1, and air-drying inhibited methane oxidation entirely.The optimum temperature of methane oxidation was about 30℃in paddy soil,while no methane oxidation was observed at 5℃or 50℃

Historical and Future Climatic Change Scenarios for Temperature and Rainfall for Iraq

The world is facing a big challenge of climatic change, mainly due to increasing concentrations of GHGs （greenhouse gases） in the atmosphere. Many researches indicated that the climate change occurred disproportionately on developing countries such as MENA （Middle East and North Africa） countries. The climatic model CGCM3.1 （T47） 2 is used in this research to explain the changes in average temperatures and the rainfall on the MENA region with special emphases on Iraq. Historical records （1900-2009） and future （2020-2099） were studied and compared; each period was divided to four sub-periods of thirty years. The results showed that the average monthly temperature for the four historical periods fluctuated between the lowest and highest value as follows： 9.2-32.9, 10.3-32.7, 9.3-32.8 and 8.6-33.9 （℃）. The rainfall for historical periods kept on the same distribution during the past 109 years, and fluctuated between the lowest and highest value of 21.3 mm and 37.6 mm with an average that reached up to 26.51 mm. For the future period, the maximum average monthly temperature reached up to 37.41 （℃） during June and minimum average monthly temperature reached up to 4.24 （℃） during January. The average monthly temperature fluctuated giving a clear impression that the future portends a higher temperature. The average monthly rainfall, for the future period, fluctuated between the lowest and highest value of 12.91 mm and 20.63 mm with an average that reached 16.84 mm which represent a reduction percentage of about 36.47% relative to the historical record of rainfall for the sanae months.

Projections of Global Mean Surface Temperature Under Future Emissions Scenarios Using a New Predictive Technique

Using numerical model simulations, global surface temperature is projected to increase by l^C to 4~C during the 21 st century, primarily as a result of increasing concentrations of greenhouse gases. In the present study, a predictive technique incorporating driving forces into an observation time series was used to project the global mean surface temperature under four representative sce- narios of future emissions over the 21st century.

Impacts of Basic Seedling on Yield-Scaled Greenhouse Gas Emissions from Rice Fields in China

Many researches showed a comprehensive assessment of the cropping practice effect on greenhouse gas （GHG） emissions per unit yield （yield-scaled） rather than per the land area （area-scaled）, and it was noteworthy that cropping practices decided to increase or decrease grain yield, and reduce or promote greenhouse gas emissions. In this study, a meta-analysis was conducted to quantify the effects of rice basic seedlings （BS） on the global warming potential （GWP） of GHG emissions at the yield-scale in China. The results suggested that significant difference was observed in yield-scaled GWP of BS. The lowest yield-scaled GWP occurred at 80-100 BS （415.65 kg CO2 equiv/mg）. The yield-scaled GHG emission from high to low was that of the hybrid rice varieties （1 028.86 kg CO2 equiv/mg）, the conventional rice varieties （634.15 kg CO2 equiv/mg） and the super rice varieties （576.57 kg CO2 equiv/mg）. Consequently, the model of conventional rice varieties and super rice varieties at 80-100 BS could be a scientifc method of matching inthe rice cropping system. A further assessment of rice density and variety impacts on GHG emissions at yield-scale was urgently needed to develop, so as to achieve win-win policies of rice production for higher yield with lower emissions.

Impact of Direct Radiative Forcing of Anthropogenic Aerosols on Diurnal Temperature Range in January in Eastern China

This study investigates the changes in January diurnal temperature range(DTR) in China during 1961-2000.The observed DTR changes during 1981-2000 relative to 1961-80 are first analyzed based on the daily temperature data at 546 weather stations.These observed DTR changes are classified into six cases depending on the changes in daily maximum and minimum temperatures,and then the occurrence frequency and magnitude of DTR change in each case are presented.Three transient simulations are then performed to understand the impact of greenhouse gases(GHGs) and aerosol direct forcing on DTR change:one without anthropogenic radiative forcing,one with anthropogenic GHGs,and another one with the combined forcing of GHGs and five species of anthropogenic aerosols.The predicted daily DTR changes during the years 1981-2000 are also classified into six cases and are compared with the observations.Results show that the previously proposed reason for DTR reduction,a stronger nocturnal warming than a daytime warming,explains only 19.8%of the observed DTR reduction days.DTR reductions are found to generally occur in northeastern China,coinciding with significant regional warming.The simulation with GHG forcing alone reproduces this type of DTR reduction with an occurrence frequency of 32.9%,which is larger than the observed value.Aerosol direct forcing reduces DTR mainly by daytime cooling.Consideration of aerosol cooling improves the simulation of occurrence frequencies of different types of DTR changes as compared to the simulation with GHGs alone,but it cannot improve the prediction of the magnitude of DTR changes.

Nuclear Power Development for Greenhouse Gas Emission Reduction in China

It is a consensus of international community to promote the development of low carbon economy in order to face the challenges of climate change. According to the features of nuclear energy, the greenhouse gas （GHG） emission of nuclear energy chain and other energy chain are compared and analyzed, and the results indicate that the GHG emission of nuclear power chain is the least in all types of power generation. The status of nuclear power development and the potential benefit in GHGs emission reduction by developing nuclear power in China are also analyzed. Active nuclear power development is a smart choice for constructing low-carbon energy structure and for addressing global climate changes in China.

Greenhouse Gases Trapping

Climate change is the main problem of mankind, especially because of it＇s increasing speed and by specialists＇ forecast the situation will become worse. Climatic changes are correlated with the degradation of biosphere. It is a question of saving life on authors planet. The authors should begin taking strong measures, else Earth has a chance to repeat the destiny of Mars and Venus, as some scientists are afraid of. So reasoning like ＂When will it be and will it be at all＂ is for lazy, careless and selfish people. Now, because of the industrial emission of greenhouse gases, the temperature of the atmosphere is growing, the climate is changing： sudden temperature differences, snowfalls where it used to be impossible, thickness of arctic ice decrease is about 40% （a great ice-hole has been found on the north pole）, repetition of droughts has increased in 8 times, power of hurricanes-2 times, increased power of floods. This is the result of lack of foresight, over-materialism and greediness, unwillingness to see the consequences because of the momentary advantages. How it is possible to trap CO2, SO2 and other gases？ Commercially gas purification at thermoelectric power stations, ferrous and non-ferrous metallurgy plants, cement and chemical plants is being made with filters and cyclones that trap solid parts, and using different absorptive and adsorptive methods. Unfortunately at present there is no effective method of COE trapping.

Global Research Trends Related to CO_2 Emissions and Their Enlightenment to China

Given the growing awareness of the likely catastrophic impacts of climate change and close association of climate change with global emissions of greenhouse gases （of which carbon dioxide is more prominent） , considerable research efforts have been devoted to the analysis of carbon dioxide （CO2） emissions and its relationship to sustainable development. Now GHG reduction programs have been coming into effect in many developed coun- tries that have more responsibility for historical CO2 emissions, and the studies have become mature. First, the GHG emissions accounting system is more all-inclusive and the methods are more rational with the effort of IPCC from 1995 and all other research- ers related. Second, the responsibility allocation is more rational and fair. Along with the clarity of ＂carbon transfer＂ and ＂carbon leakage＂, the perspective and methodology for allocating regional COz emissions responsibility is turning from production base to consumption base. Third, the decomposition method has become more mature and more complex. For example, the decomposition formulas are including KAYA expression and input-output expres- sion and the decomposition techniques are developed from index analysis to simple average divisia and then adaptive-weighting divisia. Fourth, projection models have become more integrated and long-term. The top-down model and bottom-up model are both inter-embedded and synergetic. Trends above give some advice for the research on CO2 in China, such as emissions factors database construction, deeper-going research on emissions responsibility and structure analysis, promotion of modeling technology and technology-environment database.

Modelling Soil Greenhouse Gas Fluxes from a Broad-leaved Korean Pine Forest in Changbai Mountain: Forest-DNDC Model Validation

Fluctuations in soil greenhouse gas(GHG)are an important part of the terrestrial ecosystem carbon-nitrogen cycle,but uncertainties remain about the dynamic change and budget assessment of soil GHG flux.Using high frequency and consecutive soil GHG fluxes measured with an automatic dynamic chamber system,we tested the applicability of the current Forest-DNDC model in simulating soil CH4,CO2 and N2O fluxes in a temperate broad-leaved Korean pine forest at Changbai Mountain.The results showed that the Forest-DNDC model reproduced general patterns of environmental variables,however,simulated seasonal variation in soil temperature,snow melt processes and soil moisture partly deviated from measured variables,especially during the non-growing season.The modeled CH4 flux was close to the field measurement and co-varied mainly with soil temperature and snowpack.The modeled soil CO2 flux had the same seasonal trend to that of the observation along with variation in temperature,however,simulated CO2 flux in the growing season was underestimated.The modeled N2O flux attained a peak in summer due to the influence of temperature,which was apparently different from the observed peak of N2O flux in the freeze-thaw period.Meanwhile,both modeled CO2 flux and N2O flux were dampened by rainfall events.Apart from consistent estimation of annual soil CH4 flux,the annual accumulation of CO2 and N2O was underestimated.It is still necessary to further optimize model parameters and processes using long-term high-frequency observation data,especially transference of heat and water in soil and GHG producing mechanism.Continues work will improve modeling,ecosystem carbon-nitrogen budget assessment and estimation of soil GHGs flux from the site to the region.

Regional Diferences in the Efect of Climate and Soil Texture on Soil Organic Carbon

The agricultural soil carbon pool plays an important role in mitigating greenhouse gas emission ana unaerstanamg the son orgamc carbon-climate-soil texture relationship is of great significance for estimating cropland soil carbon pool responses to climate change. Using data from 900 soil profiles, obtained from the Second National Soil Survey of China, we investigated the soil organic carbon （SOC） depth distribution in relation to climate and soil texture under various climate regimes of the cold northeast region （NER） and the warmer Huang-Huai-Hai region （HHHR） of China. The results demonstrated that the SOC content was higher in NER than in HHHR. For both regions, the SOC content at all soil depths had significant negative relationships with mean annual temperature （MAT）, but was related to mean annual precipitation （MAP） just at the surface 0-20 cm. The climate effect on SOC content was more pronounced in NER than in HHHR. Regional differences in the effect of soil texture on SOC content were not found. However, the dominant texture factors were different. The effect of sand content on SOC was more pronounced than that of clay content in NER. Conversely, the effect of clay on SOC was more pronounced than sand in HHHR. Climate and soil texture jointly explained the greatest SOC variability of 49.0% （0-20 cm） and 33.5% （20-30 cm） in NER and HHHR, respectively. Moreover, regional differences occurred in the importance of climate vs. soil texture in explaining SOC variability. In NER, the SOC content of the shallow layers （0-30 cm） was mainly determined by climate factor, specifically MAT, but the SOC content of the deeper soil layers （30-100 cm） was more affected by texture factor, specifically sand content. In HHHR, all the SOC variability in all soil layers was predominantly best explained by clay content. Therefore, when temperature was colder, the climate effect became stronger and this trend was restricted by soil depth. The regional differences and soil depth influence underscored the importance of explicitly considering them in modeling long-term soil responses to climate change and predicting potential soil carbon sequestration.