Temporal variation of wind speed in China for 1961–2007

2010 ◽  
Vol 104 (3-4) ◽  
pp. 313-324 ◽  
Author(s):  
Guobin Fu ◽  
Jingjie Yu ◽  
Yichi Zhang ◽  
Shanshan Hu ◽  
Rulin Ouyang ◽  
...  
Keyword(s):  
Wind Speed ◽  
Temporal Variation

scholarly journals Temporal Variation and Source Analysis of Carbonaceous Aerosol in Industrial Cities of Northeast China during the Spring Festival: The Case of Changchun

Atmosphere ◽  
2020 ◽  
Vol 11 (9) ◽  
pp. 991
Author(s):  
Mengduo Zhang ◽  
Shichun Zhang ◽  
Qiuyang Bao ◽  
Chengjiang Yang ◽  
Yang Qin ◽  
...  
Keyword(s):  
Wind Speed ◽  
Temporal Variation ◽  
Northeast China ◽  
Carbonaceous Aerosol ◽  
Source Analysis ◽  
Formation Mechanisms ◽  
Carbonaceous Aerosols ◽  
Industrial Cities ◽  
Spring Festival ◽  
Major Period

Carbonaceous aerosol, one of the major components of atmospheric aerosols, significantly affects haze episodes, climate change, and human health. Northeastern China suffers severe air pollution, especially in some periods (e.g., the Spring Festival). However, studies on carbonaceous aerosols in typical northeast industrial cities (i.e., Changchun) are rare, limiting further comprehension of the atmospheric haze formation. In this study, we monitored the concentrations of carbonaceous aerosols (i.e., OC and EC) in Changchun during the Lunar New Year of 2018 (i.e., from Lunar 20 December to Lunar 20 January), and analyzed the temporal variation and source contributions via the HYbrid-Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model with the potential source contribution factor weights (PSCF) method. The daily concentrations of OC and EC were 9.00 ± 2.81 and 1.57 ± 0.46 µg m−3, respectively, and were significantly lower at nighttime than at the day during the Spring Festival. The concentrations during the major period (i.e., OC: 8.13 ± 2.93 µg m−3; EC: 1.47 ± 0.47 µg m−3 in festival days), including the Lunar Little New Year; the Lunar New Year’s Eve; New Year’s Day; Lunar 5 January, and the Spring Lantern Festival, were mainly from the northwestward with the wind speed of 4–6 m/s being lower than that of normal period (OC: 9.87 ± 2.46 µg m−3; EC: 1.67 ± 0.44 µg m−3) from the southeastward with a wind speed of 6–7 m/s. The direction of the airflow trajectory was mainly in local, northwestward, and northward, carrying particulate matter and gaseous pollutants. In major period, the daily concentration of atmospheric pollutants presented a bimodal trend, with peaks appearing regularly from 11:00 a.m. to 12:00 p.m. and 5:00 p.m. 10:00 p.m., which might be related to traffic, cooking, and firecrackers. The OC/EC was greater than 2 during the whole period, indicating the generation of secondary organic aerosols (i.e., SOC). This study was essential to understand the formation mechanisms of severe pollution episodes and develop control measures for the industrial cities of Northeast China during the Spring Festival.

scholarly journals Short-term variation in near-highway air pollutant gradients on a winter morning

2010 ◽  
Vol 10 (17) ◽  
pp. 8341-8352 ◽  
Author(s):  
J. L. Durant ◽  
C. A. Ash ◽  
E. C. Wood ◽  
S. C. Herndon ◽  
J. T. Jayne ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Wind Speed ◽  
Temporal Variation ◽  
Traffic Flow ◽  
Organic Compounds ◽  
Temporal Variations ◽  
Surface Boundary ◽  
Short Term ◽  
Surface Boundary Layer ◽  
Near Highway

Abstract. Quantification of exposure to traffic-related air pollutants near highways is hampered by incomplete knowledge of the scales of temporal variation of pollutant gradients. The goal of this study was to characterize short-term temporal variation of vehicular pollutant gradients within 200–400 m of a major highway (>150 000 vehicles/d). Monitoring was done near Interstate 93 in Somerville (Massachusetts) from 06:00 to 11:00 on 16 January 2008 using a mobile monitoring platform equipped with instruments that measured ultrafine and fine particles (6–1000 nm, particle number concentration (PNC)); particle-phase (>30 nm) NO3−, SO42−, and organic compounds; volatile organic compounds (VOCs); and CO2, NO, NO2, and O3. We observed rapid changes in pollutant gradients due to variations in highway traffic flow rate, wind speed, and surface boundary layer height. Before sunrise and peak traffic flow rates, downwind concentrations of particles, CO2, NO, and NO2 were highest within 100–250 m of the highway. After sunrise pollutant levels declined sharply (e.g., PNC and NO were more than halved) and the gradients became less pronounced as wind speed increased and the surface boundary layer rose allowing mixing with cleaner air aloft. The levels of aromatic VOCs and NO3−, SO42− and organic aerosols were generally low throughout the morning, and their spatial and temporal variations were less pronounced compared to PNC and NO. O3 levels increased throughout the morning due to mixing with O3-enriched air aloft and were generally lowest near the highway reflecting reaction with NO. There was little if any evolution in the size distribution of 6–225 nm particles with distance from the highway. These results suggest that to improve the accuracy of exposure estimates to near-highway pollutants, short-term (e.g., hourly) temporal variations in pollutant gradients must be measured to reflect changes in traffic patterns and local meteorology.

scholarly journals Variação temporal do Vento e sua interação com a produção de Serapilheira em Manguezal da Amazônia

2019 ◽  
Vol 12 (6) ◽  
pp. 2204
Author(s):  
Hyago Elias Nascimento Souza ◽  
Maria Isabel Vitorino ◽  
Steel Silva Vasconcelos ◽  
Eduardo Ribeiro Marinho ◽  
Carlos José Capela Bispo
Keyword(s):  
Wind Speed ◽  
Temporal Variation ◽  
Rhizophora Mangle ◽  
Avicennia Germinans ◽  
Laguncularia Racemosa ◽  
Mangrove Forests ◽  
Temporal Space ◽  
Litterfall Production ◽  
Reproductive Material ◽  
Space Production

O vento é um fator que pode influenciar nos processos ecossistêmicos das florestas, principalmente em regiões costeiras onde sua maior atuação pode contribuir na produção de serapilheira em florestas de mangue. Nesse sentido, foi caracterizada a variação temporal da direção e velocidade do vento e sua influência na produção espaço-temporal da serapilheira em um manguezal da costa amazônica. Foram utilizadas 3 parcelas amostrais com 4 coletores de serapilheira de 1 m2 para coletas mensais. A serapilheira foi classificada nas frações folha, lenhoso e material reprodutivo (flor, fruto, propágulos + estípula). Foi realizado levantamento estrutural do mangue. Foram utilizados dados de velocidade e direção do vento da Torre Micrometeorológica da UFRA. Para avaliar a variabilidade de serapilheira ao longo do tempo e espaço em relação a velocidade do vento, foi aplicado a Análise Fatorial em Componentes Principais (ACP). A distribuição mensal de direção do vento mostrou predominância no setor leste (E) e a frequência de ventos com maior velocidade foram registrados no segundo semestre. Foram identificadas três espécies de mangue Rhizophora mangle, Avicennia germinans e Laguncularia racemosa. A ACP mostrou em 4 componentes correlação negativa com material reprodutivo e correlação positiva com lenhoso associado a variação temporal do vento. Para folha a correlação não apresentou significância estando a produção desta fração sujeita a outras variáveis meteorológicas. Contudo, o vento não apresentou influência direta na produção de serapilheira, porém sua atuação associada a sistemas precipitantes podem contribuir de forma significativa para intensificar a produção.  Wind temporal variation and Litterfall production interaction in Mangrove of the Amazon  A B S T R A C TWind is a factor that can influence the ecosystem processes of forests, mainly in coastal regions where their greater performance can contribute to the production production of litterfall in mangrove forests. Was characterized the temporal variation of the direction and wind speed and its influence on the temporal space production of the litterfall  in a mangrove of the Amazon coast. Were used 3 plots and 4 traps with 1 m2 for monthly collections. The litterfall was classified in the fractions leaf, wood and reproductive material (flower, fruit, propagules + stipules). Was a structural survey of the mangrove. Direction and wind speed data were used for the Micrometeorological Tower of UFRA. To evaluate the litterfall variability over time and space in relation to wind speed, the Principal Components Analysis (PCA) was applied. The monthly distribution of wind direction showed predominance in the eastern (E), frequency of winds with higher velocity were recorded in the second semester. In the studied plots three species Rhizophora mangle, Avicennia germinans and Laguncularia racemosa occurred. The PCA shows in 4 components negative correlation with reproductive material and positive correlation with wood associated with the temporal variation of wind. Leaf, the correlation did not present significant being the production of this fraction subject to other meteorological variables. However, the wind had no direct influence on litterfall production, but its performance associated with rainfall systems can contribute significantly to intensify production.Keywords: Wind; Litterfall; Mangrove; Amazon Coast.

scholarly journals Impact of Wind on the Spatio-Temporal Variation in Concentration of Suspended Solids in Tonle Sap Lake, Cambodia

Earth ◽  
2021 ◽  
Vol 2 (3) ◽  
pp. 424-439
Author(s):  
Michitaka Sato ◽  
Rajendra Khanal ◽  
Sovannara Uk ◽  
Sokly Siev ◽  
Ty Sok ◽  
...  
Keyword(s):  
Shear Stress ◽  
Wind Speed ◽  
Temporal Variation ◽  
Water Depth ◽  
Spatial Interpolation ◽  
Suspended Solids ◽  
High Water ◽  
Tonle Sap Lake ◽  
Tonle Sap ◽  
Spatio Temporal

Even though wind, water depth, and shear stress are important factors governing sediment resuspension in lakes, their actual relations to total suspended solids (TSS) distribution in natural environments have not been well elucidated. This study aims to elucidate the impact of the wind on the spatio-temporal variation of TSS in Tonle Sap Lake, Cambodia, during low-water (March and June, <1 m) and high-water (September and December, 8–10 m) seasons. To this end, wind and TSS data for December 2016 and March, June, and September 2017 were collected and analyzed. For spatial interpolation of wind speed, the inverse distance weighted method was found to be better (R2 = 0.49) than the vectorized average (R2 = 0.30) and inverse of the ratio of distance (R2 = 0.31). Spatial interpolation showed that the wind speed and direction on the lake were <5 m/s and southward during the low-water season and <7 m/s and westward during the high-water season. The TSS concentration in the low-water season was higher (>50 mg/L) than that in the high-water season. The TSS concentration during the low-water season was empirically described by wind speed (W), water depth (D), and shear stress (τ_wave) with a function of W3, W3/D, and exp(W/D) or exp(τ_wave), depending on the location in the lake. The critical shear stress due to wind-induced waves at most of the places in the lake was higher than the total shear stress indicated. Sedimentation was predominant in December and June, and erosion (siltation) was dominant in March. Most of the siltation in March was dominant in the southern part of the lake.

Potential evapotranspiration change and its attribution in the Qinling Mountains and surrounding area, China, during 1960–2012

2016 ◽  
Vol 7 (3) ◽  
pp. 526-541 ◽  
Author(s):  
Chong Jiang ◽  
Zhen Nie ◽  
Xingmin Mu ◽  
Fei Wang ◽  
Wenfeng Liu
Keyword(s):  
Spatial Distribution ◽  
Wind Speed ◽  
Solar Radiation ◽  
Temporal Variation ◽  
Quantitative Study ◽  
Diurnal Temperature Range ◽  
Potential Evapotranspiration ◽  
Seasonal Distribution ◽  
Qinling Mountains ◽  
Surrounding Area

Based on the observational data of 47 meteorological stations in the northern and southern regions of the Qinling Mountains (NSQ) during 1960–2012, this paper estimated the potential evapotranspiration (ET0) by using the Penman–Monteith method. Further, a quantitative study was conducted of the ET0 spatial distribution pattern, temporal variation rules, influencing factors and attributions. The conclusions were as follows. (1) The spatial distribution of annual ET0 in NSQ decreased from northeast to southwest. The seasonal distribution was summer &gt; spring &gt; autumn &gt; winter. (2) Further, 1979 and 1993 were the turning points of the ET0 trend, at which the value began to decrease or increase over the whole region and sub-regions. At the seasonal scale, in the period of 1960–1979, ET0 in spring, summer, and winter presented a decreasing trend; however, it increased slightly in autumn. During 1980–1993, ET0 in most seasons showed a downward trend except for autumn; in the period of 1994–2012, ET0 declined in summer and autumn, however it increased slightly in spring and winter. (3) The diurnal temperature range during 1960–1979 contributed most to ET0. The decrease of wind speed and solar radiation were the main cause of the ET0 decrease during 1980–2012, which offset the effect of the increase in temperature.

Temporal Variation of ETo in Recent 50 Years in Hilly Area of Central Sichuan

2014 ◽  
Vol 641-642 ◽  
pp. 255-258
Author(s):  
Ying Min Tang
Keyword(s):  
Wind Speed ◽  
Relative Humidity ◽  
Temporal Variation ◽  
Potential Evapotranspiration ◽  
Sunshine Duration ◽  
Hilly Area ◽  
Significant Decrement

Monthly potential evapotranspiration (ET0) from 1957 to 2010 is estimated with Penman-Monteith method in four stations in hilly area of central Sichuan, China. Results show thatET0has a decrease, temperature has a significant increase, relative humidity has a significant decrement, sunshine duration and wind speed have very significantly downward trends. Climate tends to warming and drying in recent 50 years.

scholarly journals Spatial and Temporal Variation of the Near-Surface Wind Environment in the Sahara Desert, North Africa

2022 ◽  
Vol 9 ◽  
Author(s):  
Weikang Shi ◽  
Zhibao Dong ◽  
Guoxiang Chen ◽  
Ziyi Bai ◽  
Fang Ma
Keyword(s):  
Wind Speed ◽  
Temporal Variation ◽  
Wind Direction ◽  
Spatial And Temporal Variation ◽  
Sahara Desert ◽  
Wind Speeds ◽  
Prevailing Wind Direction ◽  
Drift Potential ◽  
Northern Regions ◽  
Atmospheric Changes

The Sahara Desert is the largest source of dust on Earth, and has a significant impact on global atmospheric changes. Wind is the main dynamic factor controlling the transport and intensity of dust in the Sahara Desert. This study comprehensively analyzed the spatial and temporal variation in the wind regime of the Sahara Desert from 1980 to 2019 using data from 17 meteorological stations to improve awareness of global atmospheric changes and the intensity of regional aeolian activities. All wind speed parameters decreased from northwest to southeast. While there were significant differences in the trends of temporal variation in wind speed among the different regions, there was an overall decreasing trend across the Sahara Desert, with an average wind speed of 0.09 m s−1 10 a−1. This decrease was closely related to wind frequency. The easterly, westerly, and northerly winds dominated, with more complex wind direction in the northern region. Seasonal differences in wind direction were observed in all regions. The wind direction frequency of wind speeds &gt;6 m s−1 exceeded those with wind speeds &lt;6 m s−1 in the western and northern regions, whereas other regions showed an opposite pattern. The highest drift potential (DP) and resultant drift potential (RDP) were found in the western and northern regions, and during spring and winter. There was a trend of decreasing annual variation in DP and RDP in all regions. The directional variability (RDP/DP) indicated mostly intermediate and high variability in wind direction. Resultant drift direction (RDD) indicated that a mainly southwest wind direction. No apparent trends in temporal variation in RDD and RDP/DP were observed. Total DP was strongly influenced by DP and the magnitude and frequency of strong winds in the prevailing wind direction. No strong correlation between wind regimes and dune types was observed in this desert, indicating the complexity of factors affecting dune morphology.

scholarly journals Short-term variation in near-highway air pollutant gradients on a winter morning

2010 ◽  
Vol 10 (2) ◽  
pp. 5599-5626 ◽  
Author(s):  
J. L. Durant ◽  
C. A. Ash ◽  
E. C. Wood ◽  
S. C. Herndon ◽  
J. T. Jayne ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Wind Speed ◽  
Temporal Variation ◽  
Traffic Flow ◽  
Organic Compounds ◽  
Temporal Variations ◽  
Surface Boundary ◽  
Short Term ◽  
Surface Boundary Layer ◽  
Near Highway

Abstract. Quantification of exposure to traffic-related air pollutants near highways is hampered by incomplete knowledge of the scales of temporal variation of pollutant gradients. The goal of this study was to characterize short-term temporal variation of vehicular pollutant gradients within 200–400 m of a major highway (>150 000 vehicles/d). Monitoring was done near Interstate 93 in Somerville (Massachusetts) from 06:00 to 11:00 on 16 January 2008 using a mobile monitoring platform equipped with instruments that measured ultrafine and fine particles (6–1000 nm, particle number concentration (PNC)); particle-phase (>30 nm) NO3−, SO42−, and organic compounds; volatile organic compounds (VOCs); and CO2, NO, NO2, and O3. We observed rapid changes in pollutant gradients due to variations in highway traffic flow rate, wind speed, and surface boundary layer height. Before sunrise and peak traffic flow rates, downwind concentrations of particles, CO2, NO, and NO2 were highest within 100-250 m of the highway. After sunrise pollutant levels declined sharply (e.g., PNC and NO were more than halved) and the gradients became less pronounced as wind speed increased and the surface boundary layer rose allowing mixing with cleaner air aloft. The levels of aromatic VOCs and NO3−, SO42− and organic aerosols were generally low throughout the morning, and their spatial and temporal variations were less pronounced compared to PNC and NO. O3 levels increased throughout the morning due to mixing with O3-enriched air aloft and were generally lowest near the highway reflecting reaction with NO. There was little if any evolution in the size distribution of 6–225 nm particles with distance from the highway. These results suggest that to improve the accuracy of exposure estimates to near-highway pollutants, short-term (e.g., hourly) temporal variations in pollutant gradients must be measured to reflect changes in traffic patterns and local meteorology.

Characterizing the convective heat exchange with plastic shading nets under natural arid conditions

2019 ◽  
pp. 11-20
Author(s):  
Ahmed M Abdel-Ghanya ◽  
Ibrahim M Al-Helal
Keyword(s):  
Wind Speed ◽  
Thermal Radiation ◽  
Convective Heat ◽  
Convective Heat Transfer Coefficient ◽  
Convective Heat Exchange ◽  
Radiative Properties ◽  
Wooden Frame ◽  
Arid Conditions ◽  
Air Temperatures ◽  
Radiation Fluxes

Plastic nets are extensively used for shading purposes in arid regions such as in the Arabian Peninsula. Quantifying the convection exchange with shading net and understanding the mechanisms (free, mixed and forced) of convection are essential for analyzing energy exchange with shading nets. Unlike solar and thermal radiation, the convective energy, convective heat transfer coefficient and the nature of convection have never been theoretically estimated or experimentally measured for plastic nets under arid conditions. In this study, the convected heat exchanges with different plastic nets were quantified based on an energy balance applied to the nets under outdoor natural conditions. Therefore, each net was tacked onto a wooden frame, fixed horizontally at 1.5-m height over the floor. The downward and upward solar and thermal radiation fluxes were measured below and above each net on sunny days; also the wind speed over the net, and the net and air temperatures were measured, simultaneously. Nets with different porosities, colors and texture structures were used for the study. The short and long wave’s radiative properties of the nets were pre-determined in previous studies to be used. Re and Gr numbers were determined and used to characterize the convection mechanism over each net. The results showed that forced and mixed convection are the dominant modes existing over the nets during most of the day and night times. The nature of convection over nets depends mainly on the wind speed, net-air temperature difference and texture shape of the net rather than its color and its porosity.

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