两种增温方式对杉木和木荷单萜烯通量及光合特性的影响

全球增温对森林生态系统碳循环产生了重要影响,而生物源挥发性有机化合物(Biogenic volatile organic compounds,BVOCs)是生态系统中生物合成的重要次生碳代谢产物。作为BVOCs的主要组成成分,单萜烯(Monoterpenes,MTs)合成与释放在森林生态系统碳循环过程中有重要作用。以南亚热带常见树种杉木(Cunninghamia Lanceolata(Lamb.)Hook)和木荷(Schima superba Gardn.et Champ)2年生盆栽苗木为对象,设置未增温、电热线增温和红外辐射器增温3个处理,分析不同增温方式对植物MTs通量、光合作用及相关酶活性的影响。结果表明:杉木MTs通量显著高于木荷,分别为4027.634—16239.608 pmol m^(-2)s^(-1)、49.228—130.512 pmol m^(-2)s^(-1)。电热线增温导致杉木MTs通量增加约2倍,以柠檬烯和γ-松油烯为主,分别占73.3%和15.1%;红外辐射器增温处理下杉木MTs通量下降52.6%,以柠檬烯和α-松油烯为主,分别占71.3%和18.9%。不同处理间杉木气孔导度的变化趋势与其MTs通量结果类似,增温可能主要通过影响植物气孔导度从而影响MTs释放。增温处理后木荷净光合速率增加,其中电热线增温处理效果更显著(9.890μmol CO_(2) m^(-2)s^(-1)),且不同处理存在显著性差异(P<0.05)。因此,在进行全球增温模拟研究时需考虑增温方式差异,建议尽量设置多种增温方式,以便更全面反映增温的生态效应,为全球增温模型提供更可靠的数据支撑。

高温胁迫对华北地区冬小麦灌浆及产量的影响

冬小麦灌浆期高温是制约我国北方冬小麦产量的一个重要气候因素,随着全球气候变暖,日趋频繁的极端温度事件可能引起该地区冬小麦产量的大幅波动。为了明确冬小麦灌浆期异常高温对冬小麦产量的影响程度,在河北固城生态与农业气象试验站自然大田条件下,采用自由空气红外辐射增温技术,开展了冬小麦灌浆中后期短期高温处理模拟试验。结果表明,灌浆中后期短期高温胁迫致使冬小麦灌浆速率下降及灌浆持续时间缩短从而使粒重降低,在消除了影响粒重的其它因素的作用后,短期高温处理期间的午间平均冠层气温与粒重之间存在显著的负线性相关关系。高温对冬小麦产量的威胁程度由高温强度及其持续时间两个因素决定。结合了高温强度及其持续时间综合作用的高温有效度时被证明是一个能全面反映灌浆中后期高温胁迫影响的特征量。

2017-07-11—13河曲县高温天气过程分析

利用高空和地面观测资料分析了2017-07-11—13影响河曲县高温天气的东亚大陆环流特征,并对站点地附近的大气垂直速度、温度平流、非绝热因素进行了定性分析,结果表明,高空暖脊、纬向环流、地面热低压是造成这次高温天气的基本原因,前期基础温度高、太阳辐射增温、温度平流等因素是河曲县高温天气的直接动力,大气的垂直运动对这次高温天气的影响不明显。

上海地区高温期间中稻穗部温度分布特征及对空壳率的影响

根据2013年高温期间气象观测资料、中稻开花期小气候和稻穗结实的观测结果,总结高温期间水稻穗部的2种增温模式——复合增温和辐射增温;穗部温度不仅受周围的气温影响,太阳辐射强度也是影响其温度的重要因素;穗部温度随高度上升,高度越高,温度越高,穗的上部温度比下部温度高;分析2013年稻穗和小气候同步观测资料,并以具有辐射增温特征的2008年观测资料验证,得出中稻开花时间(09:00—13:00)穗部温度大于等于35℃的时间占比是衡量高温对水稻空壳率影响程度的定量指标;在气温小于35℃时,强烈的太阳辐射也能使穗部温度大于等于35℃,从而导致水稻高温不育。

体感温度的研究及业务化应用

摘要:体感温度是人们对环境温度的综合反应,与人的生活需求密切相关。本文就其概念、研究意义和方法进行了阐述,并结合乌鲁木齐地区的气候特点,提出了符合本地区的体感温度的经验公式并实现业务化应用。

抚顺地区一次白天降温现象分析

利用地面常规观测资料及Micaps再分析资料,分析了2012年4月25日抚顺市一次白天降温现象的成因。结果表明:冷平流过境,温度平流影响强烈是此次白天降温现象的最主要原因。其次,深厚云系覆盖,导致辐射增温微弱,白天未见升温。另外,白天持续降水,雨滴降落过程中不断蒸发吸收热量,使得温度持续下降。

鲁中山区一次雷雨大风天气过程分析

对2010年4月26日鲁中山区的一次雷雨大风天气过程进行了诊断分析。结果表明:高空冷涡较深厚,冷涡后部冷空气势力强,有阶梯槽结构,易于冷空气快速南下;在冷锋前后,变压明显,变压梯度大。与变压梯度相关的变压风是造成本次大风的重要因素。850hPa在华北到山东、鲁东南有两支明显风速带存在,风速大,山东中部处于强下沉气流前沿,表明较大动量的高空干冷空气下沉,同时也造成较大的动量下传。高空冷涡西南部的干冷空气与近地面太阳晴空辐射增温的共同作用,为强对流的产生提供了激发机制。雷达回波上出现弓形回波是引起地面雷雨大风的重要标志。

Thermal performance analysis of building construction with insulated walls in summer days and nights

In the present study,the insulation mechanism of building walls during the summer days and nights is investigated with a realistic approach to enhance their performance.A fiber layer,as a porous medium with air gaps,is used along the wall layers to decrease the energy loss.Meanwhile,the radiation heat flux variation during five days in a row has been considered for each side of the building,and it is tried to reach the optimum values for geometrical factors and find suitable insulation for each side of the building.A lattice Boltzmann method(LBM) based code is developed to simulate the actual chain of the heat transfer which consists of radiation,conduction,forced and natural convection combination within wall layers including fiber porous insulation.The results indicate that for the current insulation model,the effect of natural convection on the heat transfer is not negligible and the existence of the porous layer has caused a positive impact on the heat loss reduction by decreasing the circulation speed.Also,by using the optimum location and thickness for the insulation layer,it is showed that each side of the building has different rates of energy loss during a day,and for the appropriate insulation,they need to be evaluated separately.

Simulation of the Direct Radiative Effect of Mineral Dust and Sea Salt Aerosols in a Doubled Carbon Dioxide Climate

The authors examine the equilibrium climatic response to the direct radiative effect （DRE） of mineral dust and sea salt aerosols in a doubled-CO2 climate with two-way coupling of aerosol-climate interactions.In response to the drier and windier conditions,dust emissions increase by 26％ in the Sahara Desert and by 18％ on the global scale relative to present day.Sea salt emissions increase in high latitudes （＞60°） but decrease in middle latitudes （30°-60°） of both hemispheres due to the poleward shift of westerlies,leading to a 3％ decrease in global emissions.The burdens of dust and sea salt increase by 31％ and 7％ respectively,because reductions in rainfall over the tropical oceans increase the lifetime of particles in the warmer climate.The higher aerosol loading in the doubled-CO2 climate reinforces aerosol DRE by -0.2 W m-2,leading to an additional cooling of 0.1℃ at the surface compared with the climatic effects of aerosols in present day.The additional cooling from changes in natural aerosols compensates for up to 15％ of the regional warming induced by doubled CO2.

Response of Plant Growth and Biomass Accumulation to Short-term Experimental Warming in a Highland Barley System of the Tibet

Highland barley is an important staple food in the Tibet,and the Tibetan Plateau is experiencing obvious climatic warming.However,few studies have examined the warming effects on highland barley growth and biomass allocation under conditions of controlled experimental warming.This limits our ability to predict how highland barley will change as the climate changes in the future.An experiment of field warming at two magnitudes was performed in a highland barley system of the Tibet beginning in late May,2014.Infrared heaters were used to increase soil temperature.At the end of the warming experiment（September 14,2014）,plant growth parameters（plant height,basal diameter,shoot length and leaf number）,biomass accumulation parameters（total biomass,root biomass,stem biomass,leaf biomass and spike biomass）,and carbon and nitrogen concentration parameters（carbon concentration,nitrogen concentration,the ratio of carbon to nitrogen concentration in root,stem,leaf and spike）were sampled.The low-and high-level experimental warming significantly increased soil perimental warming did not significantly change.The low-and high-level experimental warming did not significantly affect plant growth parameters,biomass accumulation parameters,and carbon and nitrogen concentration parameters.There were also no significant differences of plant growth parameters,biomass accumulation parameters,and carbon and nitrogen concentration parameters between the low-and high-level experimental warming.Our findings suggest that the response of highland barley growth,total and component biomass accumulation,and carbon and nitrogen concentration to warming did not linearly change with warming magnitude in the Tibet.

Pathologic analysis on hyperplasia of mammary gland with different syndromes based on infrared radiation temperature of acupoints

OBJECTIVE:To explore the pathologic characteristics of hyperplasia of the mammary gland(HMG) by observing differences in infrared radiation temperature of points of HMG in patients with different syndromes compared with healthy controls.METHODS:AFLIRSystems Therma CAM P30 infrared thermal camera was used to detect the infrared temperature of Shanzhong(CV 17),Qimen(LR 14),Zhongwan(CV 12),Qihai(CV 6),Guanyuan(CV 4),Taixi(KI 3),and Taichong(LR 3) in 113 patients with HMG.Of these patients,71 were placed in the Liver Qi stagnation group,34 were placed in the Dysfunction of conception and thoroughfare vessels group,and 8 were placed in the Phlegm and blood stasis in combination group.The infrared radiation temperature of each point in the patients was compared with that of healthy controls,and the differences in the infrared radiation temperatures of the points in the patients were analyzed.RESULTS:Overall,the bilateral corresponding point in both the controls and patients exhibited no significant difference in infrared radiation temperature.In all cases,the infrared radiation temperature of the points from proximal to distal tended to decrease.In a comparison of the patients and controls,the infrared radiation temperature of the trunk points Shanzhong(CV 17),Qimen(LR 14),Zhongwan(CV12),Qihai(CV6),and Guanyuan(CV 4) of the patients was higher than that of the controls,while the infrared radiation temperature of the lower extremity points Taixi(KI 3) and Taichong(LR 3) was lower than that of the controls.Of these points,Shanzhong(CV 17)(P=0.0368),Zhongwan(CV 12)(P=0.0028),Qihai(CV 6)(P=0.0085),and Guanyuan(CV4)(P=0.0018) showed significant differences.In a comparison of the corresponding point on the same side in the Liver Qi stagnation group and controls,the infrared radiation temperature of Shanzhong(CV17)(P=0.0089),right-side Qimen(LR 14)(P=0.0382),Zhongwan(CV 12)(P= 0.0000),Qihai(CV 6)(P=0.0011),and Guanyuan(CV 4)(P=0.0000) of the patients was significantly higher than that of the controls,while the differences in the infrared radiation temperature of the other points were not statistically significant(P= 0.0833-0.8397).In a comparison of the corresponding point on the same side in the Dysfunction of conception and thoroughfare vessels group and controls,the infrared radiation temperature of left-side Taichong(LR 3)(P=0.0048),right-side Taichong(LR 3)(P=0.0329),left-side Taixi(KI 3)(P= 0.0171),and right-side Taixi(KI 3)(t=0.544,P= 0.0165) of the patients was significantly lower than that of the controls,while the differences in the infrared radiation temperature of the other points were not statistically significant(P=0.3793-0.9197).In a comparison of the corresponding point on the same side in the Phlegm and blood stasis in combination group and controls,the infrared radiation temperature of Shanzhong(CV 17),Qimen(LR 14),Qihai(CV 6),Guanyuan(CV 4),Taixi(KI 3),Taichong(LR 3),and Zhongwan(CV 12) tended to increase,but without statistical significance(P=0.175-.759).CONCLUSION:The corresponding points of HMG patients with different syndromes are in different deficiency/excess states.Changes in the infrared radiation temperature of the trunk points Shanzhong(CV 17),Qimen(LR 14),Zhongwan(CV 12),Qihai(CV 6),and Guanyuan(CV 4) are closely related to the pathological characteristics of the Liver Qi stagnation syndrome of HMG patients,while changes in the infrared radiation temperature of the lower extremity points Taixi(KI 3) and Taichong(LR 3) are closely related to the pathological characteristics of the Dysfunction of conception and thoroughfare vessels syndrome of HMG patients.On the whole,HMG patients with Liver Qi stagnation syndrome are characterized by "upper excess," and those with Dysfunction of conception and thoroughfare vessels syndrome are characterized by"lowerdeficiency."

Response of Microbial Communities in Soil to Multi-level Warming in a Highland Barley System of the Lhasa River

No studies have examined the effect of experimental warming on the microbial biomass and community composition of soil in agricultural ecosystem on the Qinghai-Tibet Plateau. Thus it is unclear whether the influences of experimental warming on microbial communities in soil are related to warming magnitude in croplands on this Plateau. This study performed warming experiment(control, low-and high-level) in a highland barley system of the Lhasa River in May 2014 to examine the correlation between the response of microbial communities in soil to warming and warming magnitude. Topsoil samples(0–10 and 10–20 cm) were collected on September 14, 2014. Experimental warming at both low and high levels significantly increased soil temperature by 1.02 ℃ and 1.59 ℃, respectively at the depth of 15 cm. Phospho lipid fatty acid(PLFA) method was used to determine the microbial community in soil. The low-level experimental warming did not significantly affect the soil’s total PLFA, fungi, bacteria, arbuscular mycorrhizal fungi(AMF), actinomycetes, gram-positive bacteria(G+), gram-negative bacteria(G–), protozoa, the ratio of fungi to bacteria(F/B ratio), and ratio of G+ to G–(G+/G– ratio) at the 0–10 and 10–20 cm depth. The low-level experimental warming also did not significantly alter the composition of microbial community in soil at the 0–10 and 10–20 cm depth. The high-level experimental warming significantly increased total PLFA by 74.4%, fungi by 78.0%, bacteria by 74.0%, AMF by 66.9%, actinomycetes by 81.4%, G+ by 67.0% and G– by 74.4% at the 0–10 cm depth rather than at 10–20 cm depth. The high-level experimental warming significantly altered microbial community composition in soil at the 0–10 cm depth rather than at 10-20 cm depth. Our findings suggest that the response of microbial communities in soil to warming varied with warming magnitudes in the highland barley system of the Lhasa River.