Seasonal variations in threshold wind speed for saltation depending on soil temperature and vegetation: A case study in the Gobi Desert

Abstract. The main objective of this study is to investigate the formation and evolution mechanism of the regional haze in megacity Beijing by analyzing the process of a severe haze that occurred 20–27 September 2011. Mass concentration and size distribution of aerosol particles as well as aerosol optical properties were concurrently measured at the Beijing urban atmospheric environment monitoring station. Gaseous pollutants (SO2, NO-NO2-NOx, O3, CO) and meteorological parameters (wind speed, wind direction, and relative humidity (RH)) were simultaneously monitored. Meanwhile, aerosol spatial distribution and the height of planetary boundary layer (PBL) were retrieved from the signal of satellite and LIDAR (light detection and ranging). Results showed that high intensity of local pollutants from Beijing urban source is the fundamental cause that led to the regional haze. Meteorological factors such as higher RH, weak surface wind speed, and decreasing height of PBL played an important role on the deterioration of air quality. New particle formation was considered to be the most important factor contributing the formation of haze. In order to improve the atmospheric visibility and reduce the occurrence of the haze, the mass concentration of PM2.5 at dry condition should be less than 60 µg m−3 in Beijing according to the empirical relationship of visibility, PM2.5 mass concentration and RH. This case study may provide valuable information for the public to recognize the formation mechanism of the regional haze event over the megacity, which is also useful for the government to adopt scientific approach to forecast and eliminate the occurrence of regional haze in China.

Download Full-text

Soil respiration and N2O emission in croplands under different ploughing practices: a case study in south-east China

Soil Research ◽

10.1071/sr07225 ◽

2009 ◽

Vol 47 (2) ◽

pp. 198 ◽

Cited By ~ 8

Author(s):

Shutao Chen ◽

Yao Huang

Keyword(s):

Soil Respiration ◽

Soil Temperature ◽

Agricultural Soils ◽

Field Measurements ◽

Triticum Aestivum L ◽

N2o Emission ◽

Cropping Season ◽

Significant Difference

Studies on the CO2 and N2O emission patterns of agricultural soils under different ploughing practices may provide an insight into the potential and magnitude of CO2 and N2O mitigation in highly managed farmland soils. In this study, field measurements of soil respiration and N2O flux with different ploughing depths were performed in the 2003–04 wheat (Triticum aestivum L.), 2004 maize (Zea mays L.), and 2004–05 wheat seasons. Soil temperature and moisture were simultaneously measured. Results showed that, in each cropping season, the seasonal variation in soil respiration developed with a similar pattern for different treatments, which was primarily regulated by soil temperature. This work demonstrates that ploughing depth can influence long-term loss of carbon from soil, but this was contingent on preceding cropping types. Given the same preceding cropping practice, no significant difference in N2O emission was found among different ploughing depths in each cropping season.

Download Full-text

Investigating outdoor thermal comfort of educational building complex in urban area: A case study in Universitas Kebangsaan, Bandung city

Geographica Pannonica ◽

10.5937/gp25-30430 ◽

2021 ◽

Vol 25 (2) ◽

pp. 85-101

Author(s):

Try Ramadhan ◽

Aldissain Jurizat ◽

Andina Syafrina ◽

Amat Rahmat

Keyword(s):

Wind Speed ◽

Thermal Comfort ◽

Urban Area ◽

Outer Space ◽

Influential Factors ◽

Outdoor Environment ◽

Outdoor Thermal Comfort ◽

Design Development ◽

Campus Building

Campus building was a place to accommodate various educational activities, which were both carried out indoors and outdoors. The environment, including the building and its exterior, provided thermal comfort that was influenced by the context, such as the mass of the facility, vegetation, and constructing envelope materials. The microclimate also influenced the environment, such as temperature, wind speed, and humidity. This study aimed to investigate the outdoor thermal comfort of campus building in urban area during summer, while also identifying the influential factors. This research referred to a case study, examining the thermal quality of the educational building environment using ENVI-met software, based on the Predicted Mean Vote (PMV) index as an indicator of outdoor thermal comfort, in Universitas Kebangsaan (UK). The results showed that the outdoor environment had low thermal comfort conditions during the day, as it also had different thermal satisfactory situations, due to differences in physical characteristics in each zone. This characteristics included, (1) The SVF determinant as indicators of the shading factor should be supported by the presence of vegetation and the use of pavement material, (2) Although the wind speed factor does not really affect the thermal comfort in the outdoor space, the interconnection between open gaps is likely to make breeze distribution in the area better. This study offered direction for campus planning, in order to maintain the optimal capacity of the natural environment, such as (1) Strategizing to create a better shadowing factor in the outer space, which was supported by controlling the use of pavement materials, (2) Directing the density of buildings by making open spaces more permeable, in order for better wind distribution in the area. From this study, the campus current conditions and future design development potential was also observed.

Download Full-text

The influence of wind speed, humidity, temperature and air pressure on pollutants concentrations of PM10 — Sarajevo case study using wavelet coherence approach

2016 XI International Symposium on Telecommunications (BIHTEL) ◽

10.1109/bihtel.2016.7775719 ◽

2016 ◽

Cited By ~ 2

Author(s):

Samir Avdakovic ◽

Maja Muftic Dedovic ◽

Nedis Dautbasic ◽

Jasenka Dizdarevic

Keyword(s):

Wind Speed ◽

Air Pressure ◽

Wavelet Coherence

Download Full-text

THE INFLUENCE OF WIND SPEED ON THE PV PLANT OPERATING TEMPERATURE: A CASE STUDY FOR FORTALEZA

10.26678/abcm.cobem2021.cob2021-1663 ◽

2021 ◽

Author(s):

Eliezer da Silva Holanda Neto ◽

Leticia de Oliveira Santos ◽

Carla Freitas de Andrade ◽

PAULO CARVALHO ◽

Paulo Alexandre Costa Rocha

Keyword(s):

Wind Speed ◽

Operating Temperature

Download Full-text

Wildfire and Postfire Restoration Action Effects on Microclimate and Seedling Pine Tree Survivorship

Journal of Fish and Wildlife Management ◽

10.3996/072013-jfwm-051 ◽

2014 ◽

Vol 5 (1) ◽

pp. 174-182 ◽

Cited By ~ 6

Author(s):

Donald J. Brown ◽

Ivana Mali ◽

Michael R.J. Forstner

Keyword(s):

Soil Moisture ◽

Wind Speed ◽

Soil Temperature ◽

Air Temperature ◽

Loblolly Pine ◽

Absolute Humidity ◽

Short Term ◽

Burned Areas ◽

High Severity ◽

Postfire Management

Abstract Through modification of structural characteristics, ecological processes such as fire can affect microhabitat parameters, which in turn can influence community composition dynamics. The prevalence of high-severity forest fires is increasing in the southern and western United States, creating the necessity to better understand effects of high-severity fire, and subsequent postfire management actions, on forest ecosystems. In this study we used a recent high-severity wildfire in the Lost Pines ecoregion of Texas to assess effects of the wildfire and postfire clearcutting on six microclimate parameters: air temperature, absolute humidity, mean wind speed, maximum wind speed, soil temperature, and soil moisture. We also assessed differences between burned areas and burned and subsequently clearcut areas for short-term survivorship of loblolly pine Pinus taeda seedling trees. We found that during the summer months approximately 2 y after the wildfire, mean and maximum wind speed differed between unburned and burned areas, as well as burned and burned and subsequently clearcut areas. Our results indicated air temperature, absolute humidity, soil temperature, and soil moisture did not differ between unburned and burned areas, or burned and burned and subsequently clearcut areas, during the study period. We found that short-term survivorship of loblolly pine seedling trees was influenced primarily by soil type, but was also lower in clearcut habitat compared with habitat containing dead standing trees. Ultimately, however, the outcome of the reforestation initiative will likely depend primarily on whether or not the trees can survive drought conditions in the future, and this study indicates there is flexibility in postfire management options prior to reseeding. Further, concerns about negative wildfire effects on microclimate parameters important to the endangered Houston toad Bufo (Anaxyrus) houstonensis were not supported in this study.

Download Full-text