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1.
潮州市近年来气候变化特征及水稻生产对策 总被引：7，自引：0，他引：7
潮州市地处广东省东南部 ,属南亚热带季风气候 ,水稻生产的气候资源十分丰富 ,随着全球气候变暖 ,水稻生产期间也出现了温度变暖的趋势。本文主要分析影响潮州市水稻生产农业气象因子的阶段性变化特点 ,探讨如何充分利用气候资源优势 ,实现水稻生产优质高产高效。1 潮州市水稻生产农业气象条件的变化特点1 .1 气温上升 ,积温增多水稻生长发育的起点温度要求在日平均气温1 0℃以上 ,而且当热量条件累积到一定程度后 ,才能完成其生育过程并获得产量。在潮州市 ,早稻从播种到收获需要日平均气温 1 0℃以上活动积温3 1 0 0℃左右 ,晚稻需要 3 … 相似文献
2.
1引言为了促进科技兴农,改造中低产稻田,提高水稻单产水平,根据全市冷烂田、望天田。高寒田等中低产稻田比重大、夏旱重的实际情况,引进了水稻地膜栽培技术,并与深溪镇联合在冷烂田开展了水稻地膜栽培试验。该技术具有增温、节水、抗旱、保肥、改善泥土物理性状、灭草等综合作用,因而增产作用显著。2试验设置及地膜栽培的技术要点该试验在廖忠明、李世东两农户共0．1933hm2的两块冷烂田进行。一块田的水稻品种为汕优多系1号,采用旱育浅植育秧方式,另一块田为11优1313,旱育两段育秧方式。每块田分地膜覆盖宽窄行（约941窝／hm2）和… 相似文献
3.
水稻是贵州省的主要粮食作物 ,全省 1 8个农气站中有 1 6个站进行水稻观测。从近几年水稻报表审核情况看 ,部分观测员对水稻分蘖期观测的技术把握还很差 ,具体表现为各观测数据之间的关联性、逻辑性和连贯性很差 ,经不起推敲。现将这几个问题提出 ,谈谈自己的看法 ,供大家讨论。1 水稻分蘖普期的确定在水稻观测中 ,返青期密度是必须测定的 ,而从秧田带入本田的分蘖也应作为基本苗计算。设返青期的密度为Ｍ1,分蘖普期的密度为Ｍ2 ,由水稻分蘖普期的定义可知 : Ｍ2 ∈ [( 1 5 0 % )Ｍ1,( 1 80 % )Ｍ1]这就是说 ,水稻分蘖普期的密度 ,应… 相似文献
4.
为提高水稻作物生长模型中淹涝胁迫对水稻生长和产量影响的定量评估能力,通过开展水稻盆栽淹涝试验,研究了不同淹涝胁迫程度对粳稻和籼稻植株叶片光合性能的影响,并将两者之间的关系进行了定量化,结果表明:1)两种水稻植株叶片的光量子效率AQE、最大光合速率P_m均随淹涝天数的增加而明显下降,全淹处理的下降幅度较大,受全淹处理8天后平均下降幅度近五成,而半淹处理的下降幅度较小,半淹处理8天后平均降幅约一成左右;叶片基础荧光F_0、最大荧光产额F_m和最大光化学效率F_v/F_m也均随着淹涝胁迫天数的增加出现不同程度的降低。2)植株叶片光量子效率和最大光合速率随淹涝深度和淹涝天数变化可用定量关系模型y=1-aH-bH~3T来描述,用独立的试验资料对该模型进行检验后表明,模型的模拟值与实测值有很好的一致性,两者的相关系数高、RMSE值低,模拟效果令人满意。3)全淹处理下,水稻植株叶片最大光合速率P_m和最大荧光产额F_m下降幅度具有较好的相关性,可运用荧光测定的信息来快速估计淹涝胁迫对水稻叶片光合速率影响的程度。本研究可为改进水稻模型中淹涝胁迫条件下的水稻干物质累积和产量的模拟提供依据。 相似文献
5.
云南南亚热带地区气候资源与水稻、冬播玉米的适应性 总被引：4，自引：0，他引：4
云南南亚热带地区光能资源丰富 ,不仅表现在太阳辐射量高于我国华南和华东地区 ,而且辐射强度大 ,是籼型杂交水稻、冬播玉米等作物的高产区。全年热量资源充足 ,≥ 1 0℃积温在 6 0 0 0～ 75 0 0℃·d之间。但温度年较差小 ,日较差大 ,冬暖夏凉 ,一年四季都能种植玉米 ,是云南南亚热带地区玉米气候生态的一大特点。夏季高温强度不够 ,日照时数偏少是限制杂交水稻提高结实率和产量的主要因子。全年降水适中 ,但分布不均 ,地域差异大 ,干季降水量仅占全年总降水量的 1 0 %～ 1 5 % ,冬春干旱严重制约着冬播玉米以及水稻拔节前的生长发育。发展农田水利和灌溉是云南南亚热带地区夺取水稻、冬播玉米高产、稳产最重要的措施。 相似文献
6.
7.
1前言水稻抛秧栽培是近几年兴起的一种新的栽培方式，1992年于洪区试种2．7ha，后经示范推广，到1996年大面积种植73O0ha，增产幅度为6．8％。几年种植实践表明，利用此新技术已收到省工、省力和增产节支的效果，为实现水稻生产的高产高效开辟了新途径。为探索水稻抛秧技术的科学依据，在几年种植经验基础上，我们于1995一1996年进行了抛秧田小气候、生育性状及产量效应关系的对比试验。2材料与方法两年的水稻抛秧田对比试验均在大兴乡东风村，1995年试验田O．53ha，对照田O．33ha，1996年试验田O．73ha，对照田O．92ha，供试品种为辽粳32… 相似文献
8.
9.
水稻产量预测的数值模拟方法研究 总被引：1，自引：0，他引：1
本文在1983年试验研究的基础上,进一步探讨了水稻生长与产量形成的数值模拟方法。对1983年试验建立的水稻叶、茎、根、穗等器官生长模式用梯形近似法求解得出描述水稻生长和产量形成过程的递推表达式;对水稻群体同化能力、同化物分配转移规律也进行了初步研究;并用最优化方法确定出模式参数的最优解,模拟了1984年水稻生长发育和产量形成过程。 相似文献
10.
稻田甲烷排放抑制剂实验结果分析 总被引：3，自引：0，他引：3
经过稻田试验鉴别分析，证实已试制的农药型甲烷排放抑制剂GCH和肥料型抑制剂PB-1．对水稻田甲烷排放有抑制效果并能减轻病害，对水稻有增产作用。 相似文献
11.
The halogen ions Br- and Cl- together with NO3
-, SO4
=, MSA- (methane sulfonate), Na+ and NH4
+ were analysed by ion chromatography in extracts of more than 800 aerosol cellulose filter samples taken at Ny Ålesund, Svalbard (79°N, 12°E) in spring 1996 (March 27 - May 16) within the European Union project ARCTOC (Arctic Tropospheric Ozone Chemistry). Anticorrelated variations between f-Br (filterable bromine, i.e. water soluble bromine species that can be collected by aerosol filters) and ozone within the arctic troposphere were evaluated at a resolution of 1 or 2 hours for periods with depleted ozone and 4 hours at normal ozone. A mean f-Br concentration of 11 ng m-3 (0.14 nmol m-3) was observed for the whole campaign, while maximum concentrations of 80 ng m-3 (1 nmol m-3) were detected during two total O3-depletion events (O3 drop to mixing ratios below the detection limit of < 2 ppb). Anticorrelation between f-Br and O3 was also seen during minor O3-depletion episodes (sudden drop in O3 by at least 10 ppb, but O3 still exceeding the detection limit) and even for ozone variations near its background level (40-50 ppb). A time lag of about 10 hours between the change of ozone and of f-Br concentrations could only be found during a total ozone depletion event, when f-Br reached its maximum values several hours after ozone was totally destroyed. Bromine oxide (BrO) concentrations, measured by DOAS (Differential Optical Absorption Spectroscopy), and f-Br showed a coincident variability during almost the entire campaign (except in the case of total O3-loss). Frequently enhanced anthropogenic nitrate and sulphate concentrations were observed during O3-depletion periods. At O3 concentrations < 10 ppb sulphate and nitrate exceed their typical mean level by 54% and 77%, respectively. This may indicate a possible connection between acidity and halogen release. 相似文献
12.
Laboratory Study of O(1S) Formation Process in the Photolysis of O3 and its Atmospheric Implications
Tomoki Nakayama Kenshi Takahashi Yutaka Matsumi Hitoshi Fujiwara 《Journal of Atmospheric Chemistry》2006,53(2):107-122
A high-sensitive technique to detect O(1S) atoms using vacuum ultraviolet laser-induced fluorescence (VUV-LIF) spectroscopy has been applied to study the O(1S) production process from the UV photodissociation of O3, N2O, and H2O2. The quantum yields for O(1S) formation from O3 photolysis at 215 and 220 nm are determined to be (1.4 ± 0.4) × 10−4 and (5 ± 3) × 10−5, respectively. Based on thermochemical considerations, the O(1S) formation from O3 photolysis at 215 and 220 nm is attributed to a spin-forbidden process of O(1S)+O2(X3Σg
−). Analysis of the Doppler profile of O(1S) produced from O3 photolysis at 193 nm also indicates that the O(1S) atoms are produced from the spin-forbidden process. In the photolysis of N2O and H2O2 at 193 nm, no discernible signal of O(1S) atoms has been detected. The upper limit values of the quantum yields for O(1S) production from N2O and H2O2 photolysis at 193 nm are estimated to be 8 × 10−5 and 3 × 10−5, respectively. Using the experimental results, the impact of the O(1S) formation from O3 photolysis on the atmospheric OH radical formation through the reaction of O(1S)+H2O has been estimated. The calculated results show that the contribution of the O(1S)+H2O reaction to the OH production rate is ∼2% of that of the O(1D)+H2O reaction at 30 km altitude in mid-latitude. Implications of the present laboratory experimental results for the terrestrial airglow of O(1S) at 557.7 nm have also been discussed. 相似文献
13.
Abstract We describe a one‐dimensional (1‐D) numerical model developed to simulate the chemistry of minor constituents in the stratosphere. The model incorporates most of the chemical species presently found in the upper atmosphere and has been used to investigate the effect of increasing chlorofluorocarbon (CFC) emissions on ozone (O3). Our calculations confirm previous results that O3 depletions in the 20–25 km region, the region of the O3 maximum, are very sensitive to the relative abundances of Clx and NOy in the lower stratosphere for high Clx amounts. The individual abundances of lower stratospheric Clx and NOy amounts are very sensitive to upper tropospheric mixing ratios, which, in turn, are determined largely by surface input fluxes and heterogeneous loss processes. Thus the behaviour of column O3 depletions at high Clx levels is greatly affected, albeit indirectly, by tropospheric processes. For high Clx levels the Ox flux from the stratosphere to the troposphere is dramatically reduced, leading to a large reduction in tropospheric O3. Some of the variation between different published 1‐D model results is most likely due to this critical dependence of O3 depletion on NOy‐Clx ratios. Model simulations of time‐dependent CFC effects on ozone indicate that if CFCs were to remain at constant 1980 emission rates while N2O increased at 0.25% a?1 and CH4 increased at 1% a?1, we could expect a 2.2% decrease in total column O3 (relative to the 1980 atmosphere) by the year 2000. However, if CFC emission rates were to increase by 3% a?1 (current estimates are 5–6% a?1), we would predict a depletion of 2.7% by the year 2000. The calculations for times beyond the year 2000 suggest that the effects on total O3 will begin to accelerate. If methyl chloroform emissions are added at 7% a?1 (current estimates are 7–9% a?1) to the above CFC‐N2O‐CH4 scenario we calculate total O3 depletions by the year 2000 that are 41% larger than those calculated without. This suggests that if the emissions of methyl chloroform continue to increase at their present rate then methyl chloroform could have a significant effect upon total O3. 相似文献
14.
An updated version of the Regional Acid Deposition Model(RADM)driven by meteorologicalfields derived from Chinese Regional Climate Model(CRegCM)is used to simulate seasonal variationof tropospheric ozone over the eastern China.The results show that:(1)Peak O_3 concentration moves from south China to north China responding to the changing ofsolar perpendicular incidence point from south to north.When solar perpendicular incidence pointmoves from north to south,so does the peak O_3 concentration.(2)In the eastern China.the highest O_3 month-average concentration appears in July.thelowest in January and the medium in April and October.The pattern mainly depends on the solarradiation,the concentration of O_3 precursors NO_x and NMHC and the ratio of NMHC/NO_x.(3)Daily variations of O_3 over the eastern China are clear.Namely,O_3 concentrations rise withthe sun rising and the maximums appear at noon.then O_3 concentrations decrease.The highest dailyvariation range of O_3 appears in summer(40×10~(-9) in volume fraction)and the lowest in winter(20×10~(-9) in volume fraction).(4)Daily variations of O_3 over the western China are not clear.The daily variation range of O_3 isless than 10×10~(-9) in volume fraction. 相似文献
15.
Anomalies found in the isotope ratios of ozone are traceable to the ozone formation process. Metastable electronic states may be responsible for the preferred production of the heavy molecules. While laboratory isotope data and first tropospheric results agree well in the magnitude of isotope enrichments, stratospheric measurements show often higher values. Only through the collection of ozone samples can sufficiently large amounts of gas be obtained to analyze the three isotopes 48O3, 49O3, and 50O3. Collector systems have been developed and successfully operated in the troposphere and in the stratosphere. They will play in the future an important role in atmospheric oxygen isotope studies. 相似文献
16.
We show that photochemical processes in the lower half of the troposphere are strongly affected by the presence of liquid water clouds. Especially CH2O, an important intermediate of CH4 (and of other hydrocarbon) oxidation, is subject to enhanced breakdown in the aqueous phase. This reduces the formation of HO
x
-radicals via photodissociation of CH2O in the gas phase. In the droplets, the hydrated form of CH2O, its oxidation product HCO2
–, and H2O2 recycle O2
– radicals which, in turn, react with ozone. We show that the latter reaction is a significant sink for O3. Further O3 concentrations are reduced as a result of decreased formation of O3 during periods with clouds. Additionally, NO
x
, which acts as a catalyst in the photochemical formation of O3, is depleted by clouds during the night via scavenging of N2O5. This significantly reduces NO
x
-concentrations during subsequent daylight hours, so that less NO
x
is available for O3 production. Clouds thus directly reduce the concentrations of O3, CH2O, NO
x
, and HO
x
. Indirectly, this also affects the budgets of other trace gases, such as H2O2, CO, and H2. 相似文献
17.
Surface ozone (O3) and fine particulate matter (PM2.5) are dominant air pollutants in China. Concentrations of these pollutants can show significant differences between urban and nonurban areas. However, such contrast has never been explored on the country level. This study investigates the spatiotemporal characteristics of urban-to-suburban and urban-to-background difference for O3 (Δ[O3]) and PM2.5 (Δ[PM2.5]) concentrations in China using monitoring data from 1171 urban, 110 suburban, and 15 background sites built by the China National Environmental Monitoring Center (CNEMC). On the annual mean basis, the urban-to-suburban Δ[O3] is ?3.7 ppbv in Beijing–Tianjin–Hebei, 1.0 ppbv in the Yangtze River Delta, ?3.5 ppbv in the Pearl River Delta, and ?3.8 ppbv in the Sichuan Basin. On the contrary, the urban-to-suburban Δ[PM2.5] is 15.8, ?0.3, 3.5 and 2.4 μg m?3 in those areas, respectively. The urban-to-suburban contrast is more significant in winter for both Δ[O3] and Δ[PM2.5]. In eastern China, urban-to-background differences are also moderate during summer, with ?5.1 to 6.8 ppbv for Δ[O3] and ?0.1 to 22.5 μg m?3 for Δ[PM2.5]. However, such contrasts are much larger in winter, with ?22.2 to 5.5 ppbv for Δ[O3] and 3.1 to 82.3 μg m?3 for Δ[PM2.5]. Since the urban region accounts for only 2% of the whole country’s area, the urban-dominant air quality data from the CNEMC network may overestimate winter [PM2.5] but underestimate winter [O3] over the vast domain of China. The study suggests that the CNEMC monitoring data should be used with caution for evaluating chemical models and assessing ecosystem health, which require more data outside urban areas. 相似文献
18.
大气过氧化氢（H2O2）是一种重要的光化学产物,也是硫酸盐气溶胶生成及降水酸化过程的关键氧化剂。然而,我国对H2O2的观测研究较少,尤其对雾霾期间H2O2浓度变化特征认识不足。该文介绍了冬春时段（2016年12月-2017年4月）在北京城区中国气象局的H2O2观测结果,并结合同期O3,PAN,NOX,PM2.5等污染物和气象要素观测数据,分析H2O2浓度变化特征与影响因素。观测结果表明:观测期间H2O2体积混合比（简称为浓度）为（0.65±0.59）×10-9,其中,春季浓度（0.83±0.67）×10-9高于冬季浓度（0.51±0.47）×10-9;H2O2平均日变化基本呈现单峰特征,峰值出现在18:00-21:00,比其他地区峰值出现稍晚,并滞后于O3峰值时间4~7 h;相对湿度对H2O2日峰值时间和浓度水平有影响,小于55%时日峰值出现于18:00-24:00,平均峰值浓度1.52×10-9;大于65%时日峰值出现于11:00-16:00,日峰值浓度均小于1×10-9。H2O2,O3和PAN虽然同属光化学产物,但在不同污染状况下浓度水平和变化趋势差异明显;H2O2清洁日峰值浓度高于污染日,但11:00-15:00污染日浓度略高于清洁日。 相似文献
19.
K.-Y. Wang J. A. Pyle D. E. Shallcross D. J. Larry 《Journal of Atmospheric Chemistry》2001,38(1):31-71
In part two of this series of papers on the IMS model, we present the chemistry reaction mechanism usedand compare modelled CH4, CO, and O3 witha dataset of annual surface measurements. The modelled monthly and 24-hour mean tropospheric OH concentrationsrange between 5–22 × 105 moleculescm–3, indicating an annualaveraged OH concentration of about 10 × 105 moleculescm–3. This valueis close to the estimated 9.7 ± 0.6 × 105 moleculescm–3 calculated fromthe reaction of CH3CCl3 with OH radicals.Comparison with CH4 generally shows good agreementbetween model and measurements, except for the site at Barrow where modelledwetland emission in the summer could be a factor 3 too high.For CO, the pronounced seasonality shown in the measurements is generally reproduced by the model; however, the modelled concentrations are lower thanthe measurements. This discrepancy may due to lower the CO emission,especially from biomass burning,used in the model compared with other studies.For O3, good agreement between the model and measurements is seenat locations which are away from industrial regions. The maximum discrepancies between modelled results and measurementsat tropical and remote marine sites is about 5–10 ppbv,while the discrepancies canexceed 30 ppbv in the industrial regions.Comparisons in rural areas at European and American continental sites arehighly influenced by the local photochemicalproduction, which is difficult to model with a coarse global CTM.The very large variations of O3 at these locations vary from about15–25 ppbv in Januaryto 55–65 ppbv in July–August. The observed annual O3amplitude isabout 40 ppbv compared with about 20 ppbv in the model. An overall comparison of modelled O3 with measurements shows thatthe O3seasonal surface cycle is generally governed bythe relative importance of two key mechanisms that drivea springtime ozone maximum and asummertime ozone maximum. 相似文献
20.
The kinetics of the reaction of nitrous acid (HONO) with nitric acid (HNO3), nitrate radicals (NO3) and dinitrogen pentoxide (N2O5) have been studied using Fourier transform infrared spectroscopy. Experiments were performed at 700 torr total pressure using synthetic air or argon as diluents. From the observed decay of HONO in the presence of HNO3 a rate constant of k<7×10-19 cm3 molecule-1 s-1 was derived for the reaction of HONO with HNO3. From the observed decay of HONO in the presence of mixtures of N2O5 and NO2 we have also derived upper limits for the rate constants of the reactions of HONO with NO3 and N2O5 of 2×10-15 and 7×10-19 cm3 molecule-1 s-1, respectively. These results are discussed with respect to previous studies and to the atmospheric chemistry of HONO. 相似文献