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The Influence of Local Rainy and Dry Seasons on the Diurnal Temperature Range in Nigeria
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作者 Stanley I. Echebima Andrew A. Obafemi 《Atmospheric and Climate Sciences》 CAS 2023年第2期314-332,共19页
This study analyzed the impact of the local dry and rainy seasons on diurnal temperature range (DTR), for each major climatic zone of Nigeria namely the tropical monsoon, tropical savannah and semi-arid, using meteoro... This study analyzed the impact of the local dry and rainy seasons on diurnal temperature range (DTR), for each major climatic zone of Nigeria namely the tropical monsoon, tropical savannah and semi-arid, using meteorological data from thirteen observation stations for the period 1981 to 2021. DTR was computed from the difference of minimum temperature from maximum temperature and yearly and forty one years’ monthly averages of DTR and rainfall were computed and plotted in different graphs. The overall results from each climatic zone showed that DTR fluctuates with the seasons and there is an inverse relationship between DTR and rainfall whereby the value of DTR decreases as the rainy season approaches but increases as the rainy season departs ushering in the dry season or conversely DTR increases as the dry season approaches and decreases as the dry season departs ushering-in the rainy season. Secondly, the average yearly patterns of rainfall and DTR are roughly and oppositely shaped parabolas where the peak value of rainfall is diametrically opposite to the trough value of DTR and the least or nil volume of rainfall corresponds to the highest value of DTR. Thirdly, due to the yearly seasonal cycle of dry and rainy seasons in Nigeria coupled with the inverse relationship between DTR and Rainfall, the seasonal plot of DTR and rainfall is also cyclic in pattern with DTR cycle lagging 180 degrees with the rainfall cycle and the intersection of the two cycles represents the departure of one season and onset of another season while each half-cycle represents either the dry or rainy season. Fourthly, the dependence of DTR on any season at hand in Nigeria makes DTR season-forcing. This fourth result is underpinned by a result that showed that the 1981 and 2021 patterns of DTR and 1981 and 2021 patterns of rainfall when compared were similar, the differences were in the volume of rainfall which was due to climate change that has taken place over the four decades and which also impacted DTR since DTR varies inversely with rainfall. Finally and notwithstanding the common grounds of the results stated above, the result further showed that each climatic zone of Nigeria reacts differently to the local and global climate changes leading to the magnitude of DTR and the volume of rainfall being different across climatic zones, with rainfall volume and duration decreasing towards the arid North from the Coastal South while contrariwise DTR increases towards the arid North from the Coastal South. 展开更多
关键词 Dry season Rainy season Harmattan Period Primary and Secondary Axes of a Graph
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Seasonal Dynamics of the Soil Moisture in Yuanmou Dry-Hot Valley of Yunnan
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作者 Yuanjiao Zhao Wenhua Su +2 位作者 Guangfei Zhang Fengtao Cui Rui Zhou 《Meteorological and Environmental Research》 CAS 2013年第4期56-58,共3页
[ Objective] The research aimed to study seasonal dynamics of the soil moisture in Yuanmou Dry-Hot Valley of Yunnan. [ Method] We investigated soil moisture in rainy season in Yuanmou Dry-Hot Valley. By combining comp... [ Objective] The research aimed to study seasonal dynamics of the soil moisture in Yuanmou Dry-Hot Valley of Yunnan. [ Method] We investigated soil moisture in rainy season in Yuanmou Dry-Hot Valley. By combining completed research about soil moisture in dry season, data in rainy and dry seasons were contrasted to study seasonal dynamics of the soil moisture in the zone. [ Resultl Soil moisture in rainy season increased with the depth of soil, but would decrease within 1.0 m below the root layer. The soil moisture of grassland was higher than that of the woodland, while soil moisture of the savanna was higher than that of the woodland but lower than that of the grassland. In addition, compared with soil mois- ture in dry season, it is clear that to avoid forming permanent soil desiccation, based on soil and hydrology conditions in Yuanmou, it is better to plant grass not tree in Yuanmou when we do something about ecological restoration. [ Condusion] The research had certain guidance significance for planting agricultural and economic crops and carrying out ecological restoration in Yuanmou Dry-Hot Valley. 展开更多
关键词 Dry-hot Valley seasonal dynamics Soil moisture content Soil desiccation China
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A Study on the Chemical Compositions of the Jasminum Sambac (L. ) Aiton in Various Farming Seasons During the Blossom Period in Fuzhou Region
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作者 Guo Youjia, Dai Liang, Yang Lanping and Ren Qing (Fujian Institute of Reserch on the Structure of Matter, Academia sinica, Fuzhou, 350002) 《福建分析测试》 CAS 1998年第1期785-792,共8页
The chemical compositions of the head space,essential oil and absolute of jasmin flowers in different farming seasons during the blossom period in Fuzhou were reported in this paper.
关键词 chemical compesitions jasmin FLOWER FARMING seasonS blossom PERIOD GC/MS GC Fuzhou
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Clinical Observation on Treatment of Moderate and Severe Periodical Mastalgia with TCM Hot-wet Compress Therapy 被引量:1
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作者 Qiao HUANG Yujian SUN +6 位作者 Na FU Fang XIE Hao DONG Wenjie ZHAO Chun WANG Huan LIANG Dongxiao ZHANG 《Medicinal Plant》 CAS 2018年第4期83-86,共4页
[Objectives] To observe the clinical therapeutic efficacy of local hot-wet compress therapy of digestion ointment prescription on the patients with moderate and severe mastalgia. [Methods] Firstly,60 patients with mas... [Objectives] To observe the clinical therapeutic efficacy of local hot-wet compress therapy of digestion ointment prescription on the patients with moderate and severe mastalgia. [Methods] Firstly,60 patients with mastalgia were selected,and divided into the experimental group and control group( 30 cases for each group). The control group was treated with acupuncture at distal point,and the experimental group was treated with TCM local hot-wet compress therapy combined with acupuncture at distal point. Then,the clinical therapeutic efficacy of two groups was compared. [Results]The experimental group was superior to the control group in relieving the breast pain,improving emotional integral,reducing breast lumps,improving lump texture,and improving TCM syndrome integral( P < 0. 05). [Conclusions]The digestion ointment prescription local hot-wet compress therapy has a significant therapeutic effect on treatment of mastalgia and can significantly improve the breast pain symptom of patients. 展开更多
关键词 Periodical mastalgia MODERATE SEVERE hot-wet compress therapy Digestion ointment External therapy of TCM
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Agroclimatological Characteristics of Rainy Seasons in Southwestern Burkina Faso during the 1970-2013 Period
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作者 Boubacar Ibrahim Moussa Waongo +2 位作者 Moussa Sidibe Safietou Sanfo Boubacar Barry 《Atmospheric and Climate Sciences》 2022年第2期330-357,共28页
The different drought phases observed during the 1970-2010 period have underlined important weaknesses of West African agricultural systems. The droughts resulted in important decreases in crop production, triggering ... The different drought phases observed during the 1970-2010 period have underlined important weaknesses of West African agricultural systems. The droughts resulted in important decreases in crop production, triggering a significant deficit in food availability. Many studies have identified changes in rain events seasonal patterns as the key drivers of agricultural production failure during these drought phases. In this study, seven agriculturally-relevant intra-seasonal rainfall characteristics (i.e., annual rainfall amount, onset and cessation of the rainy season, dry spells, extreme rain events, hot spells, and strong winds) and associated constraints to crop growth are described for the main cereals (maize, millet, and sorghum) in southwestern Burkina Faso. These characteristics are calculated or determined using daily climate data from a local network of 16 weather stations spanning the 1970-2013 period. A computation of the intensity and the occurrence of these phenomena during the rainy seasons helped to draw the rainy seasons’ nomenclature. Findings suggest that the rainy seasons during the drought phases are characterized by low annual rainfall amount, late onset, early cessation and more frequent long dry spells (>7 days). Furthermore, the long dry spells mostly occurred during the most sensitive phases of crop development: germination at the beginning of the rainy season and flowering at the end of the rainy season. Also, the intensity and the probability of occurrence of the other extreme events (hot spells and strong winds) during rainy seasons are very high in the establishment phase. Thus, adaptation strategies to mitigate these unfavorable climate conditions include a selection of short-cycle crop varieties combined with supplementary irrigation systems during long dry spells. 展开更多
关键词 Climate Variability Rainy season Dry Spell hot Spell Burkina Faso
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CLINICAL OBSERVATION ON TREATMENT OF 60 CASES OF ASTHMA WITH RED-HOT NEEDLE IN THE DOG DAYS
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作者 MA Xin- ping(马新平) 《World Journal of Acupuncture-Moxibustion》 2003年第4期50-52,共3页
In the present paper, a total of 109 asthma patients were randomly divided into treatment group (red hot needle, n=62) and control group (conventional acupuncture, n=47). The treatment was conducted beginning from the... In the present paper, a total of 109 asthma patients were randomly divided into treatment group (red hot needle, n=62) and control group (conventional acupuncture, n=47). The treatment was conducted beginning from the first day of the first 10 day period of the Dog Days. After successive two years’ treatment, results showed that of the 62 and 47 cases in treatment and control groups, 16 and 7 were cured basically, 37 and 16 had remarkable improvement, 8 and 12 were ameliorated, 1 and 10 failed in the treatment, with the effective rate being 98.4% and 78.7% respectively, displaying that the therapeutic effect of treatment group was significantly superior to that of control group (P<0.01). 展开更多
关键词 Asthma Red-hot NEEDLE therapy Treatment in the three 10-day periods of dog DAYS
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Survival,growth and immune activity of scallop Chlamys farreri cultured at different depths in Haizhou Bay(Yellow Sea,China) during hot season 被引量:1
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作者 于宗赫 杨红生 +3 位作者 刘保忠 邢坤 张立斌 许强 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2010年第3期498-507,共10页
Survival, growth and immune response of the scallop, Chlamys farreri, cultured in lantern nets at five different depths (2, 5, 10, 15, and 20 m below the sea surface) were studied in Haizhou Bay during the hot season ... Survival, growth and immune response of the scallop, Chlamys farreri, cultured in lantern nets at five different depths (2, 5, 10, 15, and 20 m below the sea surface) were studied in Haizhou Bay during the hot season (summer and autumn) of 2007. Survival and growth rates were quantified bimonthly. Immune activities in hemolymph (superoxide dismutase (SOD) and acid phosphatase (ACP)) were measured to evaluate the health of scallops at the end of the study. Environmental parameters at the five depths were also monitored during the experiment. Mortalities mainly occurred during summer. Survival of scallops suspended at 15 m (78.0%) and 20 m (86.7%) was significantly higher than at 2 m (62.9%), 5 m (60.8%) or 10 m (66.8%) at the end of the study. Mean shell height grew significantly faster at 10 m (205.0 μm/d) and 20 m (236.9 μm/d) than at 2, 5 or 15 m in summer (July 9 to September 1); however, shell growth rate at 20 m was significantly lower than at the other four depths in autumn (September 2 to November 6). In contrast to summer, scallops at 5 m grew faster (262.9 μm/d) during autumn. The growth of soft tissue at different depths showed a similar trend to the shell. Growth rates of shell height and soft tissue were faster in autumn than in summer, with the exception of shell height at 20 m. SOD activity of scallops increased with depth, and ACP activity was significantly higher at 15 and 20 m than at other depths, which suggests that scallops were healthier near the bottom. Factors explaining the depth-related mortality and growth of scallops are also discussed. We conclude that the mass mortality of scallop, C. farreri, during summer can be prevented by moving the culture area to deeper water and yield can be maximized by suspending the scallops in deep water during summer and then transferring them to shallow water in autumn. 展开更多
关键词 Chlamysfarreri SURVIVAL GROWTH mortality immune activity hot season water depth
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Energy Budget over Seasonal Snow Surface at an Open Site and Beneath Forest Canopy Openness during the Snowmelt Period in Western Tianshan Mountains,China 被引量:1
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作者 LU Heng WEI Wen-shou +2 位作者 LIU Mingzhe HAN Xi HONG Wen 《Journal of Mountain Science》 SCIE CSCD 2015年第2期298-312,共15页
In this study, meteorological factors and snowmelt rate at an open site on sunny slope(OPS) and beneath forest canopy openness on shady slope(BFC) were measured using an automatic weather station and snow lysimeter du... In this study, meteorological factors and snowmelt rate at an open site on sunny slope(OPS) and beneath forest canopy openness on shady slope(BFC) were measured using an automatic weather station and snow lysimeter during the snowmelt period in 2009, 2010 and 2013. The energy budget over snow surface was calculated according to these meteorological datasets. The analysis results indicated that the net shortwave radiation(K) and sensible heat flux(H) were energy sources, and the latent heat flux(LVE) was energy sinks of snow surfaces at all sites. The net longwave radiation(L) was energy sink at OPS and 80% BFC, but energy source at 20% BFC. The gain of K, H, and the loss of LVE at BFC were obviously lower than those at OPS. The L was the maximum difference of energy budget between snow surface at BFC and OPS. In warm and wet years, the most important factor of the energy budget variation at OPS was air humidity and the second mostimportant factor was air temperature. However, the ground surface temperature on the sunny slope was the most important factor for L and energy budget at BFC. With the increases in forest canopy openness and the slope of adjacent terrains, the influences of ground surface temperature on the sunny slope on L and the energy budget over snow surface at BFC increased, especially when the snow cover on the sunny slope melts completely. 展开更多
关键词 Energy budget seasonal snow Snowmelt period Tianshan Mountains
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Seasonal prediction of extreme high-temperature days over the Yangtze River basin
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作者 Shifeng PAN Zhicong YIN +4 位作者 Mingkeng DUAN Tingting HAN Yi FAN Yangyang HUANG Huijun WANG 《Science China Earth Sciences》 SCIE EI CAS CSCD 2024年第7期2137-2147,共11页
Extreme high temperatures occur frequently over the densely populated Yangtze River basin(YRB)in China during summer,significantly impacting the local economic development and ecological system.However,accurate predic... Extreme high temperatures occur frequently over the densely populated Yangtze River basin(YRB)in China during summer,significantly impacting the local economic development and ecological system.However,accurate prediction of extreme high-temperature days in this region remains a challenge.Unfortunately,the Climate Forecast System Version 2(CFSv2)exhibits poor performance in this regard.Thus,based on the interannual increment approach,we develop a hybrid seasonal prediction model over the YRB(HM_(YRB))to improve the prediction of extreme high-temperature days in summer.The HM_(YRB)relies on the following four predictors:the observed preceding April-May snowmelt in north western Europe;the snow depth in March over the central Siberian Plateau;the CFSv2-forecasted concurrent summer sea surface temperatures around the Maritime Continent;and the 200-hPa geopotential height over the Tibetan Plateau.The HM_(YRB)indicates good capabilities in predicting the interannual variability and trend of extreme high-temperature days,with a markable correlation coefficient of 0.58 and a percentage of the same sign(PSS)of 76% during 1983-2015 in the one-year-out cross-validation.Additionally,the HM_(YRB) maintains high PSS skill(86%)and robustness in the independent prediction period(2016-2022).Furthermore,the HM_(YRB) shows a good performance for years with high occurrence of extreme high-temperature days,with a hit ratio of 40%.These predictors used in HM_(YRB)are beneficial in terms of the prediction skill for the average daily maximum temperature in summer over the YRB,albeit with biases existing in the magnitude.Our study provides promising insights into the prediction of 2022-like hot extremes over the YRB in China. 展开更多
关键词 hot extremes Yangtze River basin CFSv2 seasonal prediction One-year-out cross-validation
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Uses of the Buys-Ballot Table in Time Series Analysis
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作者 Iheanyi S. Iwueze Eleazar C. Nwogu +1 位作者 Ohakwe Johnson Jude C. Ajaraogu 《Applied Mathematics》 2011年第5期633-645,共13页
Uses of the Buys-Ballot table for choice of appropriate transformation (using the Bartlett technique), assessment of trend and seasonal components and choice of model for time series decomposition are discussed in thi... Uses of the Buys-Ballot table for choice of appropriate transformation (using the Bartlett technique), assessment of trend and seasonal components and choice of model for time series decomposition are discussed in this paper. Uses discussed are illustrated with numerical examples when trend curve is linear, quadratic and exponential. 展开更多
关键词 Buys-Ballot TABLE Trend ASSESSMENT ASSESSMENT of seasonALITY Periodic AVERAGES seasonal AVERAGES Data Transformation Choice of Model
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River Flows Influence on Nutrients (Si, N and P) and Fecal Coliforms (E. coli) in Two Tributaries of the Estuarine Channel of Bertioga (Santos Estuary, São Paulo, Brazil)
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作者 Bruno Otero Sutti Luciana Lopes Guimarães +1 位作者 Roberto Pereira Borges Elisabete de Santis Braga 《Journal of Geoscience and Environment Protection》 2022年第6期26-46,共21页
Sewage introduction into rivers has altered the physical and chemical properties of waters and also the microbial metabolism. This study aimed to evaluate the Escherichia coli and nutrient concentrations in the Maratu... Sewage introduction into rivers has altered the physical and chemical properties of waters and also the microbial metabolism. This study aimed to evaluate the Escherichia coli and nutrient concentrations in the Maratu&#227;and Crumaú rivers (Santos Estuary, Brazil) during two periods with distinct magnitudes of freshwater runoff, verifying possible relation of abiotic changes with the microbial metabolism. Water sampling was performed in October/2012 (dry season) and January/2013 (rainy season) at two points in the Crumaú river (upstream and downstream zone) and one in the Maratu&#227;river (downstream zone). The water subsamples were obtained for E. coli and nutrient analyses while the velocity of water flow, water level, temperature, salinity, and dissolved oxygen were measured in situ. The E. coli concentrations were under the detection limit in the Maratu&#227;downstream during the dry season reaching a maximum value (1.47 × 10<sup>4</sup> CFU/100mL) in the Crumaú upstream during the rainy season. E. coli presented strong positive correlation with nutrients (ammoniacal-N and phosphate), evidencing the sewage source in the Crumaú upstream shown by this association. In both periods, the low oxygen saturation (100 μmol·L<sup>-1</sup>) indicated considerable predominance of heterotrophic metabolism in the Crumaú upstream. The low dissolved oxygen values in Crumaú River are corroborated to show a low self-depuration capacity in the rainy period due to maintenance of high nutrient and E. coli at two points in the Crumaú river (upstream and downstream zone) and one in the Maratu&#227;river (downstream zone). Besides, these results evidenced that the tendency of the metabolism changed from autotrophic to heterotrophic under high river flow events at this studied estuarine sector located at Santos estuarine complex. 展开更多
关键词 EUTROPHICATION Domestic Sewage Water Quality seasonal Period ESTUARY
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Employment survey in the graduation season
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作者 Zhong Mengxia 《China Textile》 2020年第5期22-25,共4页
Since the outbreak of the COVID-19,China's economy has been hit hard.Because of the pandemic,the overall employment situation this year is particularly grim,especially for fresh graduates.The demand of enterprises... Since the outbreak of the COVID-19,China's economy has been hit hard.Because of the pandemic,the overall employment situation this year is particularly grim,especially for fresh graduates.The demand of enterprises for graduates has decreased by 22%compared with the previous year in the same period. 展开更多
关键词 ENTERPRISES season period.
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Analysis of Season Change in Jiyang from Meteorological Standpoint
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作者 刘树峰 苏轶 《Agricultural Science & Technology》 CAS 2012年第5期1073-1075,共3页
[Objective] The aim was to analyze changing characters of four seasons in Jiyang, providing references for farming and disaster prevention in the area. [Methed] Changing characters of initial time and lasting periods ... [Objective] The aim was to analyze changing characters of four seasons in Jiyang, providing references for farming and disaster prevention in the area. [Methed] Changing characters of initial time and lasting periods of four seasons in Jiyang for 30 years were analyzed from meteorological standpoint with weather information from 1981 to 2010 observed in surface meteorological observation in Jiyang. [Result] Recent 30 years, initial time of spring and winter in Jiyang were earlier than before, especially for spring. In contrast, initial time of summer and autumn were later, especially for autumn. In addition, periods of spring and winter declined and the latter changed more significantly. Meanwhile, periods of summer and autumn extended and rate of linear trend for summer period was 0.042 hou/year. [Conclusion] The research indicated that lasting days of summer extended significantly and of spring and winter shortened under the background of global warming. 展开更多
关键词 Four seasons Initial time Lasting period Changing trend
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Quilitative Analysis of a Class of Simulate Seasons Environm ent Chem ostat Systems 被引量:1
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作者 宋国华 杨晓忠 李秀琴 《Chinese Quarterly Journal of Mathematics》 CSCD 1998年第4期77-82, ,共6页
In this paper, a class of chemostat systems with simulate seasons Environment in the following form =(1+be(t)-s)Q+x(msa+s-k) =x(msa+s-k)-Qxis discussed. It is abstained that the system has not periodic solution when b... In this paper, a class of chemostat systems with simulate seasons Environment in the following form =(1+be(t)-s)Q+x(msa+s-k) =x(msa+s-k)-Qxis discussed. It is abstained that the system has not periodic solution when b=0; if b≠0 and b1 then system has 2 π periodic solution of system. globally asymptotically stable as mQ<μ *-1 and is unstable as mQ>μ *-1 and there exists at last one minimal 2 π periodic solution (s(t),x(t)) with \{x(t)>0,\}0<s(t)<s *(t). 展开更多
关键词 simulate seasons environment periodic solution quilitative analysis
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Profile distribution and seasonal dynamics of water-extractable carbohydrate in soils under mixed broad-leaved Korean pine forest on Changbai Mountain 被引量:7
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作者 ZHAO Shan-shan SUN Jin-bing CUI Xiao-yang 《Journal of Forestry Research》 SCIE CAS CSCD 2013年第3期509-514,共6页
Carbohydrate represents an important part of the soil labile organic carbon pool. Water soluble carbohydrate drives the C cycle in forest soil by affecting microbial activity and hot water extractable car- bohydrate i... Carbohydrate represents an important part of the soil labile organic carbon pool. Water soluble carbohydrate drives the C cycle in forest soil by affecting microbial activity and hot water extractable car- bohydrate is thought related to soil carbon sequestration due to the asso- ciation with soil aggregation. In a temperate forest region of northeast China, Changbai Mountain, we investigated the abundance, spatial dis- tribution, and seasonal dynamics of cool and hot-water extractable car- bohydrate in soils under mixed broad-leaved Korean pine forest. The concentrations of cool-water extractable carbohydrate (CWECH) in three soil layers (0-5, 5-10, 10-20 cm) ranged from 4.1 to 193.3 g.kg-1 dry soil, decreasing rapidly with soil depth. On an annual average, the CWECH concentrations in soils at depths of 5-10 and 10-20 cm were 54.2% and 24.0%, respectively, of that in the 0-5 cm soil layer. CWECH showed distinct seasonal dynamics with the highest concentrations in early spring, lowest in summer, and increasing concentrations in autumn. Hot-water extractable carbohydrate (HWECH) concentrations in three soil layers ranged from 121.4 to 2026.2 g.kgq dry soil, which were about one order of magnitude higher than CWECH. The abundance of HWECH was even more profile-dependent than CWECH, and decreased more rapidly with soil depth. On an annual average, the HWECH concentration in soils 10-20 cm deep was about one order of magnitude lower than that in the top 0-5 cm soil. The seasonality of HWECH roughly tracked that of CWECH but with seasonal fluctuations of smaller amplitude. The car- bohydrate concentrations in cool/hot water extracts of soil were positively correlated with UV254 and UV2s0 of the same solution, which has implications for predicting the leaching loss of water soluble organic carbon. 展开更多
关键词 forest soil cool-water extractable carbohydrate hot-waterextractable carbohydrate profile distribution seasonal dynamics
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Seasonal characteristics and provenance of organic aerosols in the urban atmosphere of Liaocheng in the North China Plain:Significant effect of biomass burning 被引量:1
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作者 Yuanyuan Li Min Chen +6 位作者 Yachen Wang Tonglin Huang Gehui Wang Zheng Li Jianjun Li jingjing Meng Zhanfang Hou 《Particuology》 SCIE EI CAS CSCD 2023年第4期185-198,共14页
To better understand the seasonal characteristics of urban organic aerosol(OA)in the North China Plain(NCP),PM2.5 samples in the urban atmosphere of Liaocheng were collected and analyzed.The molecular distribution of ... To better understand the seasonal characteristics of urban organic aerosol(OA)in the North China Plain(NCP),PM2.5 samples in the urban atmosphere of Liaocheng were collected and analyzed.The molecular distribution of the organic markers in the urban atmosphere of Liaocheng reveals that n-alkanes(39.3%)was the most abundant species all year round,followed by saccharides(28.2%),phthalic acids(Ph,20.8%),biogenic secondary organic aerosol(BSOA)tracers(9.4%),and polycyclic aromatic hydrocarbon(PAHs,2.3%).PM2.5,organic carbon(OC),elemental carbon(EC),and primary organic markers exhibit the highest concentrations in winter,due largely to the increased biomass burning and coal combustion for house heating in local and surrounding regions.However,the concentration and relative abundance of BSOA are significantly higher in summer than other seasons,induced by the more favorable meteoro-logical conditions that would promote the emissions of biogenic volatile organic compounds(BVOCs)and the secondary production of BSOA.The ratios of OC/EC and 3-methyl-1,2,3-butanetricarboxylic acid to cis-pinic acid plus cis-pinonic acid(MBTCA/(PA+PNA)are higher in the warm seasons than those in the cold seasons,indicating that the oxidation of OA is sensitive to air temperature.Compared to 2017,the concentration level of PAHs during wintertime decreased by 40.8%,confirming that the stringent regulation of coal burning is effective.The highest concentration of high molecular weight(HMW)n-alkanes and three anhydrosugars in winter,and the close correlation of levoglucosan with HMW n-al-kanes suggests that the impact of biomass burning was more significant in winter.The same seasonal characteristic of the ratios of high-/low-NO_(x) products with NO_(x) and the strong correlation of high-/low-NO_(x) products with levoglucosan indicate that the formation of isoprene SOA(SOA1)tracers was signif-icantly influenced by anthropogenic emissions.The molecular compositions,the distributions of fire spots,backward trajectories of air masses,and correlation analysis suggest that air pollution events in spring were primarily resulted from biomass burning and secondary oxidation,while pollution events in winter were largely driven by the increased combustion sources,and promoted aqueous secondary formation.Our results suggest that the reduction of biomass and coal combustion should be taken into account to improve the urban air quality in the NCP. 展开更多
关键词 Organic aerosol(OA)markers seasonal variations Pollution periods Biomass burning the north China Plain(NCP)
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Hot Season for Textile Graduates Job Hunting
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作者 Liu Yi 《China Textile》 2011年第1期54-55,共2页
The economy is recovering in most parts of the world, which marks its entering into a post-crisis era. The financial crisis breaking out in the new century gave a heavy blow on the world's employment. As the unemp... The economy is recovering in most parts of the world, which marks its entering into a post-crisis era. The financial crisis breaking out in the new century gave a heavy blow on the world's employment. As the unemployment rate was setting a new record in America, which made Obama's approval ratings plummeting, Chinese textile graduates will make their own career decisions. 展开更多
关键词 hot season for Textile Graduates Job Hunting
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近50年滇池流域汛期降水时空演变特征分析 被引量:1
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作者 邓丽仙 杨帆 +4 位作者 杨洋 李姣 赵兰兰 胡成龙 李长江 《水文》 CSCD 北大核心 2024年第2期113-120,127,共9页
以滇池流域1970—2020年汛期(5—10月)降水量资料为依据,利用地理信息技术,采用Mann-Kendall检验法、小波分析等方法,分析近50年来滇池流域汛期降水年际变化的趋势性、周期性以及集中度、集中期、降水中心和旱涝发生频率等演变特征。结... 以滇池流域1970—2020年汛期(5—10月)降水量资料为依据,利用地理信息技术,采用Mann-Kendall检验法、小波分析等方法,分析近50年来滇池流域汛期降水年际变化的趋势性、周期性以及集中度、集中期、降水中心和旱涝发生频率等演变特征。结果表明:(1)近50年来,滇池流域汛期降水总体呈减少趋势,中部地区降水呈增加趋势,盘龙江上游的松华坝水库以上区域及南部地区降水呈减少趋势;(2)汛期降水年际变化存在31 a的主周期,中部主城区降水集中度高于南部地区;(3)汛期降水的中心整体呈现向东部、南部方向偏移的态势,且移动趋势显著;(4)滇池流域旱涝频发,尤其盘龙江中段昆明主城区为旱涝多发区。该成果对滇池流域水旱灾害防御及水资源管理具有参考意义。 展开更多
关键词 滇池流域 汛期降水 集中度 集中期 降水中心 旱涝特征
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近136年(1885~2020年)长江中下游伏旱期划分及其演变分析
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作者 徐群 赵亮 《大气科学》 CSCD 北大核心 2024年第3期1072-1094,共23页
少雨高温的伏旱期对长江中下游地区农业、水利和人体健康等具有重要影响,但目前缺乏对该地区伏旱期的历史划分,对其长期变化规律也缺乏充分认识。本文利用1885年以来已划定的长江中下游沿江五站(上海、南京、芜湖、九江和汉口)梅雨期和... 少雨高温的伏旱期对长江中下游地区农业、水利和人体健康等具有重要影响,但目前缺乏对该地区伏旱期的历史划分,对其长期变化规律也缺乏充分认识。本文利用1885年以来已划定的长江中下游沿江五站(上海、南京、芜湖、九江和汉口)梅雨期和夏季日气温、降水资料,对出梅后的少雨高温时段分别确定了少雨和高温的定量标准,划定出1885~2020年长江中下游伏旱期,并用统一气温标准结合伏旱期长度,综合确定了近136 a(1885~2020年)伏旱期强度指数。这136 a(包含有16个无伏旱年及10个入秋伏旱年)里伏旱期的年平均长度为21.6 d,呈现出3~6 a、36 a和84 a周期。1951年以来,1959~1978年是伏旱期长度的主要峰期,1980~1987年是伏旱期长度的下降谷期,之后缓慢增加;1980年代之后虽然大于30 d的长伏旱期有减少趋势,但是15~30 d且高强度的伏旱期频现;1995年之后秋伏旱明显增多,夏季延迟。136 a里最长且强的伏旱期依次出现于1934、1967、1978和2013年;最早的伏旱期出现在6月中旬,最晚在9月中下旬。近40 a来,伏旱期高温(≥35.0°C)日数大幅提高,伏旱期高温发生率从1980年代的30%左右上升到近年的50%以上,对人体健康构成威胁。长(强)伏旱期的副热带环流特征为西太平洋副热带高压稳定控制长江中下游区,而短(弱)伏旱期西太平洋副热带高压多偏东或偏南,入秋伏旱与副热带高压稳定西伸有关。伏旱期内高温日数的演变受到双重人类活动的制约,它不仅与人类活动导致的全球海陆升温有关,并且因地而异,即受到局地生态环境演变和城市热岛效应增减的人为作用影响。印度—太平洋季风区陆海温差对长江中下游伏旱期长度年代际变化有重要调制作用。 展开更多
关键词 长江中下游 伏旱期 准周期演变 人类活动 高温
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不同发酵时期对黑蒜调味粉品质的影响
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作者 王帅 武帅兵 贺羽 《中国调味品》 CAS 北大核心 2024年第3期87-91,共5页
黑蒜富含微量元素与营养物质,作为一种食品或保健品在市面上流行。黑蒜的品质也引起了人们的广泛关注。普通黑蒜是用新鲜完整的带皮生蒜在高温高湿的发酵箱中自然发酵90~120 d后制成的。然而生蒜是如何在发酵过程中逐渐变黑、黑蒜与生... 黑蒜富含微量元素与营养物质,作为一种食品或保健品在市面上流行。黑蒜的品质也引起了人们的广泛关注。普通黑蒜是用新鲜完整的带皮生蒜在高温高湿的发酵箱中自然发酵90~120 d后制成的。然而生蒜是如何在发酵过程中逐渐变黑、黑蒜与生蒜极大的口感差别以及两者营养价值的变化基于什么成为人们疑惑的问题。该研究选取品相完好的紫皮独头蒜,在专业的黑蒜发酵锅中发酵10 d,获得发酵成功的黑蒜,并在发酵过程中对不同发酵时期的黑蒜进行质构测定,经过干燥破碎,制成调味蒜粉,并对其中的还原糖含量、总酸含量、总酚含量、水分含量、粗脂肪含量、蛋白质含量进行测定,由此探寻蒜在发酵过程中产生的变化,从而对不同发酵时期黑蒜调味粉的品质进行综合评价。该研究可拓展关于调味品发酵方面的知识,为提高新型功能性调味粉的营养价值提供更多的数据资源。 展开更多
关键词 黑蒜 干燥破碎 调味粉 发酵时期 品质
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