西安太阳总辐射时空变化特征及对城市发展的响应

根据西安辐射站太阳总辐射资料和周围23个气象台站日照百分率资料,建立1961-2009年西安市太阳总辐射资料时间序列,运用模糊聚类分析法将全市分为3个区,采取滑动t检验法进行突变检验及阶段分析,研究西安太阳总辐射的时空分布及变化特征.同时引用西安历年城区人口数据,对城区太阳总辐射与城市发展进行了相关性分析.结果表明:西安太阳总辐射具有东部多、西部次之、中部少的分布特征;1961-2009年呈波段减少的变化趋势,线性倾向率为-2.01％/10a,其中1977-1991年为显著减少阶段,以中部减少幅度最大;其间出现两次突变,突变年分别为1977年及1992年;城市发展带来大气污染物的增加,造成西安城区太阳总辐射对城市发展有较大的响应,西安城市发展对太阳总辐射季节影响上表现为冬、夏季远大于春、秋季.     

Ecosystem response to solar ultraviolet-B radiation: influence of trophic-level interactions

Solar ultraviolet radiation (UVR) can reduce the photosynthesis and growth of benthic diatom communities in shallow freshwater. Nevertheless, greater amounts of algae accumulate in UVR-exposed habitats than in UVR-protected environments. Near-ultraviolet (UVA wavelengths of 320 to 400 nanometers) and mid-ultraviolet (UVB, wavelengths of 280 to 320 nanometers) radiation also inhibit algal consumers (Diptera: Chironomidae). Larval chironomids are more sensitive to UVB than sympatric algae. Differential sensitivity to UVB between algae and herbivores contributes to counterintuitive increases in algae in habitats exposed to UVB. These mesocosm experiments illustrate that predictions of the response of entire ecosystems to elevated UVB cannot be made on single trophic-level assessments.     

Stratospheric ozone, middle ultraviolet radiation, and carbon-14 measurements of marine productivity

The effects of increased ultraviolet radiation, due to decreased stratospheric ozone, on marine phytoplankton have been investigated with the use of static bottle in situ carbon-14 productivity measurements. The relative biological efficiency for photoinhibition may be used to calculate biologically effective doses and resultant amplification factors. The carbon-14 technique (short-term incubations) is inadequate for assessment of possible large amplification factor photoprocesses that may be ecologically significant.     

自然主义的哈尼稻作及其可持续发展

\t\t\t\t\t目的\t\t\t\t\t探究水稻秸秆的饲用特征对UV-B辐射的响应。\t\t\t\t\t\t\t\t\t\t\t\t\t方法\t\t\t\t\t通过大田原位模拟试验,以元阳梯田传统水稻品种白脚老粳为材料,研究不同强度UV-B辐射处理(0、2.5、5.0和7.5 kJ/m²)对水稻秸秆生长形态(茎秆长、茎粗和生物量)和饲用化学成分(粗纤维、粗脂肪、粗灰分、粗蛋白、中性洗涤纤维、酸性洗涤纤维、淀粉、可溶性糖和非蛋白氮)的影响,并分析秸秆的品质营养价值指数(秸秆的可吸收营养物质总量TDN、净能NE₁、秸秆干物质采食量DMI、可消化的干物质DDM和相对饲料价值RFV)。\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t结果\t\t\t\t\t随着UV-B辐射增强,水稻秸秆的长度和茎粗增加,生物量下降。不同UV-B辐射增强处理下,水稻秸秆的粗蛋白含量、粗纤维含量、粗脂肪含量、粗灰分含量和中性洗涤纤维含量没有显著的差异;非蛋白氮含量、淀粉含量和可溶性糖含量表现出单峰变化规律;酸性洗涤纤维含量在2.5 kJ/m² UV-B辐射处理时最低。2.5和5.0 kJ/m² UV-B辐射处理时,形态响应指数、饲用品质响应指数和综合响应指数较高;2.5 kJ/m² UV-B辐射处理时,秸秆的品质营养价值指数TDN、NE₁、DMI、DDM和RFV最高,分别为46.92 g/kg、5.01 MJ/kg、1.93 g/kg、56.05 g/kg和83.85%。\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t结论\t\t\t\t\t适当的UV-B辐射能提高水稻秸秆的饲用特征,UV-B辐射为2.5 kJ/m²时水稻秸秆饲用特征较好。\t\t\t\t\t\t\t\t\t     

植物对UV-B辐射的响应与调控机制

目的研究不同UV-B辐射处理对水稻不同生育时期(分蘖期、拔节期和抽穗期)叶片氮代谢及其产量的影响。方法以元阳梯田水稻品种白脚老粳为材料,大田原位种植,研究不同UV-B辐射强度(0、2.5、5.0和7.5 kJ/m²)对水稻各生育时期叶片氮代谢关键酶[硝酸还原酶(NR)、谷氨酰胺合成酶(GS)和谷氨酸合成酶(GOGAT)]活性、含氮物质(可溶性蛋白与总游离氨基酸)含量及产量构成指标(有效穗数、穗粒数、千粒质量、结实率及产量)的影响。结果与对照相比,2.5 kJ/m² UV-B辐射时水稻抽穗期GS活性、拔节期GOGAT活性、分蘖期和抽穗期总游离氨基酸含量显著提高(P<0.05);5.0 kJ/m² UV-B辐射时水稻分蘖期NR活性、各生育期GS和GOGAT酶活性、可溶性蛋白及游离氨基酸含量显著增加(P<0.05),拔节期NR活性显著降低(P<0.05);7.5 kJ/m² UV-B辐射时水稻各生育时期叶片的NR、GS与GOGAT活性、可溶性蛋白含量及总氨基酸含量均显著降低(P<0.05)。UV-B辐射增强抑制白脚老粳有效穗数、穗粒数、结实率和千粒质量,导致产量下降,7.5 kJ/m² UV-B辐射强度下产量下降幅度最大为22.8%。结论大田增强UV-B辐射对元阳梯田地方水稻品种叶片氮代谢影响有显著的“剂量+生育时期”效应,中低强度UV-B辐射对水稻氮代谢有促进作用,UV-B辐射强度为5.0 kJ/m²时最为显著,高强度UV-B辐射对水稻氮代谢有抑制作用。增强UV-B辐射导致水稻产量下降。     

Modeling the climatic response to orbital variations

According to the astronomical theory of climate, variations in the earth's orbit are the fundamental cause of the succession of Pleistocene ice ages. This article summarizes how the theory has evolved since the pioneer studies of James Croll and Milutin Milankovitch, reviews recent evidence that supports the theory, and argues that a major opportunity is at hand to investigate the physical mechanisms by which the climate system responds to orbital forcing. After a survey of the kinds of models that have been applied to this problem, a strategy is suggested for building simple, physically motivated models, and a time-dependent model is developed that simulates the history of planetary glaciation for the past 500,000 years. Ignoring anthropogenic and other possible sources of variation acting at frequencies higher than one cycle per 19,000 years, this model predicts that the long-term cooling trend which began some 6000 years ago will continue for the next 23,000 years.     

日光温室番茄群体太阳总辐射量的分布规律及其与光合作用的关系

【目的】研究日光温室番茄群体的太阳总辐射量分布规律,为优化日光温室结构、控制日光温室环境提供理论依据。【方法】将日光温室番茄冠层按高度均匀分为4层,观测不同冠层的太阳总辐射量、叶面积指数、净光合速率和太阳总辐射透光率,探讨群体太阳总辐射量的变化规律及其与光合作用的关系。【结果】在番茄盛果期,日光温室内的太阳总辐射量南部明显高于北部,平均高出200 W/m2以上;中部略高于东、西部。太阳总辐射量在植株群体内垂直方向上随冠层高度的下降而减少,1.2,0.9,0.6和0.3 m冠层的太阳总辐射量日平均值分别为507,398,289和76 W/m2;越靠近冠层底部太阳总辐射量衰减的日变化越不明显。随着冠层高度的降低,累积叶面积指数增大,太阳总辐射量减小。净光合速率由冠层顶部向底部表现为随累积叶面积指数的增加而降低,随着太阳总辐射透光率的减少而减小,冠层顶部净光合速率最大,为22.59μmol/(m2.s),冠层底部最小,为8.00μmol/(m2.s)。【结论】日光温室中番茄群体太阳总辐射量的分布规律为:南部高于北部,中部略高于东、西部;太阳总辐射量分布与冠层高度、累积叶面积指数和净光合速率均有一定的相关性。     

Evidence for large upward trends of ultraviolet-B radiation linked to ozone depletion

Spectral measurements of ultraviolet-B radiation made at Toronto since 1989 indicate that the intensity of light at wavelengths near 300 nanometers has increased by 35 percent per year in winter and 7 percent per year in summer. The wavelength dependence of these trends indicates that the increase is caused by the downward trend in total ozone that was measured at Toronto during the same period. The trend at wavelengths between 320 and 325 nanometers is essentially zero.     

Measurement of solar radiation exergy

Methods of estimating the energy of solar radiation during it conversion into other forms of energy-thermal, photoelectric, and chemical-during photosynthesis of plants are examined. Analytical expressions are given for estimating the conversion of the energy of solar radiation into thermal, photoelectric, and photosynthetic exergy for the purpose of realizing it in the software and hardware parts of the measuring instrument.     

Solar ultraviolet radiation and coral reef epifauna

Many "shade-loving" reef organisms show adverse effects when irradiated with full natural sunlight but not if radiation shorter than 400 nanometers is screened out. Shortwave solar radiation appears to be an important physical factor controlling the biology of shallow tropical benthic marine communities.     

日光温室内各表面太阳辐射照度的模拟计算

建立了温室内各表面太阳辐照度计算模型,并对沈阳地区跨度为12 m的日光温室进行模拟,分析了温室建筑参数改变对温室内各表面太阳辐射照度的影响。结果表明:冬季最冷月(2003 12至2004 02)温室内后坡单位面积太阳辐射照度分别为土壤表面及后墙面的1.45和1.49倍;温室地面太阳辐射照度模拟结果与实际测试结果差值不超过5%。改变温室跨度和高度分别对地面及北墙面太阳辐射照度有较大影响,且呈线性关系;改变温室后坡仰角对温室内各表面太阳辐射照度的影响不显著。     

Stratospheric response to trace gas perturbations: changes in ozone and temperature distributions

The stratospheric concentration of trace gases released in the atmosphere as a result of human activities is increasing at a rate of 5 to 8 percent per year in the case of the chlorofluorocarbons (CFCs), 1 percent per year in the case of methane (CH(4)), and 0.25 percent per year in the case of nitrous oxide (N(2)O). The amount of carbon dioxide (CO(2)) is expected to double before the end of the 21st century. Even if the production of the CFCs remains limited according to the protocol for the protection of the ozone layer signed in September 1987 in Montreal, the abundance of active chlorine (2 parts per billion by volume in the early 1980s) is expected to reach 6 to7 parts per billion by volume by 2050. The impact of these increases on stratospheric temperature and ozone was investigated with a two-dimensional numerical model. The model includes interactive radiation, wave and mean flow dynamics, and 40 trace species. An increase in CFCs caused ozone depletion in the model, with the largest losses near the stratopause and, in the vertical mean, at high latitudes. Increased CO(2) caused ozone amounts to increase through cooling, with the largest increases again near 45 kilometers and at high latitudes. This CO(2)-induced poleward increase reduced the CFC-induced poleward decrease. Poleward and downward ozone transport played a major role in determining the latitudinal variation in column ozone changes.     

Astronomy and solar physics: very-wide-field ultraviolet sky survey

Very-wide-field photographs of the sky were taken on Spacelab 1 at 1650, 1930, and 2530 angstroms with a limiting magnitude of 9.3 at 1930 angstroms. A 1.2 by 2.4 kiloparsec ultraviolet extension of the Shapley wing of the Small Magellanic Cloud is seen in some of the photographs.     

Sea-level solar radiation in the biologically active spectrum

Calculations show a significant depletion of ultraviolet and visible radiation due to absorption and scattering by particulates and cloud drops for a fixed amount of ozone.     

紫外线处理米蛾卵对赤眼蜂繁殖的影响

为弄清紫外线处理米蛾卯时杀胚效果较好的照射时间、间距及紫外线处理米蛾卵对赤眼蜂繁殖的影响,明确缩短距离、延长时间照射米蛾卵对赤眼蜂繁殖是否有负面影响,研究了米蛾卵在距离单管40 W紫外灯10、20、30、40 cm处,分别照射10、20、30、40、50、60 min后米蛾的孵化率,以及照射后的米蛾卵上赤眼蜂的单雌平均寄生粒数、羽化率和性比的差异.结果显示,照射20 min以上的处理组孵化率为0％或极低,间距较大的处理组(30、40 cm)孵化率高于间距较小的处理组(10、20 cm).为保证杀胚效果,紫外线照射米蛾卵时应控制在间距10～20 cm,时间20～60 min;紫外线处理后,赤眼蜂单雌平均寄生粒数由对照(不经过紫外线处理)的39.33粒增加到50～60粒,羽化率由61.15％提高到70％～80％,两者与对照差异显著;缩短紫外灯和米蛾卵之间的距离至10、20 cm,或延长照射时间至50、60 min,对赤眼蜂的单雌平均寄生粒数、羽化率和性比无显著性影响.     

Mariner 9 ultraviolet spectrometer experiment: seasonal variation of ozone on Mars

Ozone is observed to be present in the polar regions of Mars and to have a seasonal variation. In the summer, the amount present in the polar atmosphere is less than 3 micrometer-atmospheres. In the fall, ozone increases in amount and is found in association with the formation of the polar hood. In winter, the maximum amount of ozone is present, 57 micrometer-atmospheres over the polar hood and 16 over the polar cap. In spring, the amount over the polar cap decreases monotonically until by the beginning of summer the ozone disappears. Ozone is not observed in the equatorial region during any season.