Project Aquarius 4. Experimental Bushfires, Suppression Procedures, and Measurements

1997 ◽  
Vol 7 (2) ◽  
pp. 99 ◽  
Author(s):  
GM Budd ◽  
JR Brotherhood ◽  
AL Hendrie ◽  
SE Jeffery ◽  
FA Beasley ◽  
...  
Keyword(s):  
Wind Speed ◽  
Relative Humidity ◽  
Air Temperature ◽  
Fire Intensity ◽  
Subjective Responses ◽  
Hand Tool ◽  
Infra Red ◽  
Fire Front ◽  
Forest Fire Danger ◽  
Eucalypt Forests

Experimental bushfires were lit over three summers in Australian eucalypt forests with fuel loads (mean and range) of 11.3 (8-14) tonnes per hectare, in air temperature 25 (17-33)° C, relative humidity 47 (14-81)%, and wind speed 4.4 (2-9) m s-1. The McArthur Forest Fire Danger Index (FFDI) ranged from 2 to 18 and was evenly distributed between 'low', 'moderate', and 'high' fire dangers. Fires were lit on a crosswind ignition line of 50-200 metres, and were allowed to develop for 10-50 minutes before a seven-man hand-tool crew commenced its attack. Airborne infra-red imagery showed that head-fire intensity (averaged over 6 minutes) of most fires exceeded 1000 kW per metre of fire front (kW m-1) at some stage and ranged as high as 3280 kW m-1, challenging the crew in much the same way as summer wildfires and evoking similar uncertainty and apprehension. Firefighters were generally unable to suppress headfires with an intensity of more than 1000 kW m-1. Comprehensive measurements were made of the stresses the firefighters and scientific observers experienced, their physiological and subjective responses, and the firefighters' productivity and efficiency. In all, 23 km of fireline were constructed and 238 man-days of measurements were obtained — 179 on the firefighters, 59 on the scientists.

Empirical Equations to Estimate Evapotranspiration in Mosul City

2020 ◽  
Vol 27 (4) ◽  
pp. 98-102
Author(s):  
Haqqi Yasin ◽  
Luma Abdullah
Keyword(s):  
Wind Speed ◽  
Relative Humidity ◽  
Air Temperature ◽  
Reference Evapotranspiration ◽  
Sunshine Duration ◽  
Food And Agriculture ◽  
Food And Agriculture Organization ◽  
Daily Data ◽  
Daily Sunshine ◽  
Measured Wind Speed

Average daily data of solar radiation, relative humidity, wind speed and air temperature from 1980 to 2008 are used to estimate the daily reference evapotranspiration in the Mosul City, North of Iraq. ETo calculator software with the Penman Monteith method standardized by the Food and Agriculture Organization is used for calculations. Further, a nonlinear regression approach using SPSS Statistics is utilized to drive the daily reference evapotranspiration relationships in which ETo is function to one or more of the average daily air temperature, actual daily sunshine duration, measured wind speed at 2m height and relative humidity

The atmospheric conditions affecting sporulation of blue mould in tobacco

1964 ◽  
Vol 4 (13) ◽  
pp. 178 ◽  
Author(s):  
BG Collins
Keyword(s):  
Wind Speed ◽  
Relative Humidity ◽  
Air Temperature ◽  
Critical Parameter ◽  
Leaf Surface ◽  
Atmospheric Conditions ◽  
Blue Mould ◽  
Growing Seasons ◽  
Ambient Relative Humidity ◽  
Critical Relative Humidity

Conditions favouring sporulation of blue mould (Peronospora tabacina Adam) having been established in the laboratory, a theoretical model has now been used to express the critical parameter, i.e. the relative humidity near the leaf surface where the spores form, in terms of the ambient atmospheric conditions. To test the validity of this model, wind speed, air temperature, and relative humidity mere measured over four growing seasons in three tobacco crops in the Ovens Valley, Victoria, and related to times of sporulation of the mould observed concurrently in these crops. 'Critical relative humidity,' a function of wind speed, air temperature, and heat loss from the crop is shown to be a more serviceable indicator of likelihood of sporulation than either ambient relative humidity or rainfall.

POSSIBLE CHANGES OF CLIMATE CONDITIONS IN UKRAINE TO THE MIDDLE OF THE XXI CENTURY

2020 ◽  
pp. 94-100
Author(s):  
L.V. Malytska ◽  
V. O Balabukh
Keyword(s):  
Climate Change ◽  
Wind Speed ◽  
Relative Humidity ◽  
Air Temperature ◽  
Climate Model ◽  
Temporal Distribution ◽  
Climatic Parameters ◽  
Average Wind Speed ◽  
Climate Conditions ◽  
A1b Scenario

In Ukraine, as in the world, substantial climatic changes have happened throughout past decades. It is a fact that they are manifested in changing of parameters of the thermal regime, regimes of wind and humidity. It is expected that they will be observed also in future that will lead to aggravation of negative effects and risks due to climate change. That determines the relevance of the problem of forecasting such changes in future both globally and regionally. After all, knowledge of climate’s behavior in future is very important in the development of strategies, program and measures to adapt to climate change. The article is devoted to assessing spatio-temporal distribution main climatic indicators (air temperature, wind speed and relative humidity) in Ukraine, their variability and the probable values to the middle of the 21st century (2021-2050). Projection of changes in meteorological conditions was made for A1B scenario of SRES family using data of the regional climate model REMO and data from the hydrometeorological observation network of Ukraine (175 stations). Estimated data obtained from the European FP-6 ENSEMBLES project with a resolution of 25 km. For spatial distribution (mapping) we used open-source Geographic Information System QGIS, type of geographic coordinate system for project is WGS84. In the middle of the XXI century, if A1B scenario is released, it is expected a significant changes of climatic parameters regarding the 1981-2010 climatic norm: air temperature is rise by 1,5 °C, average wind speed is decrease by 5-8%, relative humidity in winter probably drop by 2%, but in summer it rises by 1,5%. The unidirectionality of the changes is characteristic only of air temperature, for wind speed and relative humidity the changes are in different directions. The intensity of changes is also not uniform across the country for all climatic parameters, has its regional and seasonal features. Statistical likelihood for most of highlighted changes for all climatic parameters is 66 % and more, the air temperature change is virtually certain (p-level <0.001).

An Evaluation of NDFD Weather Forecasts for Wildland Fire Behavior Prediction

2018 ◽  
Vol 33 (1) ◽  
pp. 301-315 ◽  
Author(s):  
Wesley G. Page ◽  
Natalie S. Wagenbrenner ◽  
Bret W. Butler ◽  
Jason M. Forthofer ◽  
Chris Gibson
Keyword(s):  
United States ◽  
Wind Speed ◽  
Relative Humidity ◽  
Air Temperature ◽  
Wildland Fire ◽  
Fire Behavior ◽  
The United States ◽  
Mean Bias Error ◽  
Bias Error ◽  
Behavior Prediction

Abstract Wildland fire managers in the United States currently utilize the gridded forecasts from the National Digital Forecast Database (NDFD) to make fire behavior predictions across complex landscapes during large wildfires. However, little is known about the NDFDs performance in remote locations with complex topography for weather variables important for fire behavior prediction, including air temperature, relative humidity, and wind speed. In this study NDFD forecasts for calendar year 2015 were evaluated in fire-prone locations across the conterminous United States during periods with the potential for active fire spread using the model performance statistics of root-mean-square error (RMSE), mean fractional bias (MFB), and mean bias error (MBE). Results indicated that NDFD forecasts of air temperature and relative humidity performed well with RMSEs of about 2°C and 10%–11%, respectively. However, wind speed was increasingly underpredicted when observed wind speeds exceeded about 4 m s−1, with MFB and MBE values of approximately −15% and −0.5 m s−1, respectively. The importance of accurate wind speed forecasts in terms of fire behavior prediction was confirmed, and the forecast accuracies needed to achieve “good” surface head fire rate-of-spread predictions were estimated as ±20%–30% of the observed wind speed. Weather station location, the specific forecast office, and terrain complexity had the largest impacts on wind speed forecast error, although the relatively low variance explained by the model (~37%) suggests that other variables are likely to be important. Based on these results it is suggested that wildland fire managers should use caution when utilizing the NDFD wind speed forecasts if high wind speed events are anticipated.

Estimating error in wind speed measurements for experimental fires

2001 ◽  
Vol 31 (3) ◽  
pp. 401-409 ◽  
Author(s):  
A L Sullivan ◽  
I K Knight
Keyword(s):  
Wind Speed ◽  
Small Scale ◽  
Confidence Limits ◽  
Single Measure ◽  
Rate Of Spread ◽  
Scale Size ◽  
Fire Front ◽  
Scalar Measure ◽  
Eucalypt Forests ◽  
Measured Wind Speed

Most experimental fires, by nature, are small scale ([Formula: see text]100 m), and rate of spread measurements are taken over periods of several minutes. The aim of empirical fire modellers is to ascribe a single measure of rate of forward spread over a period to a single scalar measure of wind. The actual wind affecting the fire is unmeasurable; its value must be estimated from remote anemometry. Observation and consideration of the spatial and temporal statistics of the wind has allowed confidence limits to be placed upon the accuracy with which the measured wind reflects the wind acting on the fire front. Experimental data to verify these estimates was gathered during Project Vesta, a study into high-intensity fires in dry eucalypt forests. An equation that quantifies the accuracy of the estimate of wind affecting the fire front is given. The accuracy increases with time scale, size of the fire front, and density of anemometry. When applied to a measured wind speed taken some distance from the fire, it gives a useful estimate of the likely variation of the corresponding wind at the fire front.

scholarly journals Microclimatic studies in summer moong (Vigna Radiata L. Wilczek) and bare fields

MAUSAM ◽  
2021 ◽  
Vol 42 (3) ◽  
pp. 265-268
Author(s):  
SURENDER SINGH ◽  
V.U.M. RAO ◽  
DIW AN SINGH
Keyword(s):  
Wind Speed ◽  
Relative Humidity ◽  
Air Temperature ◽  
Vigna Radiata ◽  
Maturity Stage ◽  
Average Relative Humidity

An experiment was conducted to study the microclimate of summer moong in relation to bare field. Albedo values were higher at flowering than maturity stage. Air temperature values were lower in cropped field than bare field values at flowering and maturity stage. The average relative humidity deviations were 1.8,4.4,5.0 and 3.6 per cent at flowering and 2.2, 3.0,4.2, 3.8 and. 3.2 per cent at maturity stage at 0800, 1000, 1200, 1400 and 1700 IST. The wind speed values were lower in lower in  cropped  field than bare field.

scholarly journals THIRTEEN YEARS OF WEATHER STATISTICS AT SAN PEDRO MARTIR OBSERVATORY

2020 ◽  
Vol 56 (2) ◽  
pp. 295-319
Author(s):  
I. Plauchu-Frayn ◽  
E. Colorado ◽  
M. G. Richer ◽  
C. Herrera-Vázquez
Keyword(s):  
Seasonal Variation ◽  
Wind Speed ◽  
Relative Humidity ◽  
Air Temperature ◽  
Summer Season ◽  
San Pedro ◽  
Weather Stations ◽  
Sierra San Pedro Martir ◽  
Rain Precipitation

We present weather statistics for thirteen years of data gathered with the meteorological stations at Observatorio Astronómico Nacional in the Sierra San Pedro Mártir (OAN-SPM) over the period 2007–2019. These weather stations include sensors that measure various climatological variables. The median values of the air temperature are 10.3° C and 7.0° C for daytime and nighttime, respectively. The relative humidity follows a seasonal variation with April-June being the driest months. The median values for the sustained wind speed are 11 and 14 km hr-1 for daytime and nighttime data, respectively. Preferred wind directions are SSW and North. Sustained winds are stronger at night and during December, January and February. The annual mean rain precipitation is 313 mm, most of which occurs during the summer season as afternoon thunderstorms.

scholarly journals Investigation on the Temperature Distribution of Asphalt Overlay on the Existing Cement Concrete Pavement in Hot-Humid Climate in Southern China

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Zuzhong Li ◽  
Yayun Zhang ◽  
Chunguang Fa ◽  
Xiaoming Zou ◽  
Haiwei Xie ◽  
...  
Keyword(s):  
Wind Speed ◽  
Relative Humidity ◽  
Solar Radiation ◽  
Prediction Model ◽  
Air Temperature ◽  
Concrete Pavement ◽  
Humid Climate ◽  
Temperature Prediction ◽  
Asphalt Overlay ◽  
Hot Humid Climate

Temperature is known to be one of the most important factors affecting the design and performance of asphalt concrete pavement. The distresses of asphalt overlay are closely related to its temperature, particularly in Guangxi, a hot-humid-climate region in China. This research is to analyze the impact of meteorological factors on temperature at 2 cm depth in asphalt overlay by ReliefF algorithm and also obtain the temperature prediction model using MATLAB. Two test sites were installed to monitor the temperatures at different pavement depths from 2014 to 2016; meanwhile, the meteorological data (including air temperature, solar radiation, wind speed, and relative humidity) were collected from the two meteorological stations. It has been found that the temperature at 2 cm depth experiences greater temperature variation, and the maximum and minimum temperatures of asphalt overlay, respectively, occur at 2 cm depth and on the surface. Besides, the results of ReliefF algorithm have also shown that the temperature at 2 cm depth is affected significantly by solar radiation, air temperature, wind speed, and the relative humidity. Based on these analyses, the prediction model of maximum temperature at 2 cm depth is developed using statistical regression. Moreover, the data collected in 2017 are used to validate the accuracy of the model. Compared with the existing models, the developed model was confirmed to be more effective for temperature prediction in hot-humid region. In addition, the analysis of rutting depth and overlay deformation for the two test sections with different materials is done, and the results have shown that reasonable structure and materials of asphalt overlay are vital to promote the high-temperature antideforming capability of pavement.

scholarly journals Future scenarios of thermal bioclimatic conditions in a humid tropical city under urban development

2018 ◽  
Vol 13 (5) ◽  
pp. 1
Author(s):  
Vicente De Paulo Rodrigues da Silva ◽  
Joel Silva Santos ◽  
Eduardo Rodrigues Viana de Lima ◽  
Romildo Morant de Holanda ◽  
Enio Pereira de Sousa ◽  
...  
Keyword(s):  
Wind Speed ◽  
Relative Humidity ◽  
Air Temperature ◽  
Urban Areas ◽  
Kendall Test ◽  
Future Scenarios ◽  
Rapid Urbanization ◽  
Mann Kendall Test ◽  
Bioclimatic Conditions ◽  
The City

Urbanization modifies the heat balance in urban areas and has negative effects on landscape, aesthetics, energy efficiency, human health and the inhabitants’ quality of life. This work evaluated future scenarios of bioclimatic conditions for João Pessoa, a humid tropical city in Northeast Brazil. The scenarios were determined based on trends in air temperature, relative humidity and wind speed for the time period from 1968 to 2015. The study was performed for two distinct periods of three months each (dry and wet seasons) using data from weather stations equipped with thermo-hygrometers and cup anemometers located in nine representative areas of the city. Trends in air temperature, relative humidity, wind speed, and effective temperature index (ET index) time series were evaluated using the Mann-Kendall test. Results indicated that the air temperature showed an increasing trend of 0.34°C/decade, whereas the relative humidity showed a decreasing trend of 0.49%/decade and the wind speed values ranged from 1.3 ms-1 to 3.80 ms-1. These trends are statistically significant according to the Mann-Kendall test (p<0.05). The air temperature increased between the 1980s and 2010s, which corresponds to a period of rapid urbanization of the city. Future environmental conditions in João Pessoa will be determined in accordance with the urbanization processes.

scholarly journals Microclimate in silvipastoral systems with eucalyptus in rank with different heights

2010 ◽  
Vol 39 (3) ◽  
pp. 685-694 ◽  
Author(s):  
Wander de Souza ◽  
Orlando Rus Barbosa ◽  
Jair de Araújo Marques ◽  
Marco Aurélio Teixeira Costa ◽  
Eliane Gasparino ◽  
...  
Keyword(s):  
Wind Speed ◽  
Relative Humidity ◽  
Air Temperature ◽  
Thermal Load ◽  
Heat Load ◽  
Temperature Humidity Index ◽  
Heat Load Index ◽  
Humidity Index ◽  
Globe Temperature ◽  
Black Globe Temperature

The aim of this work was to verify if the presence of trees and its height in formed silvipastoral systems with eucalyptus planted in rank can modify the microclimate and improve the environment for bovine raising during the day in summer. It was evaluated the microclimate of the environment in formed silvipastoral systems in rank of eucalyptus with 8 m, 18 m and 28 meters of height, compared to a system no shade in the summer. The experimental design was a split plot with six hour time in sub parcels. The systems are made up of parcels and the months as block in four replications and the interaction hour × system. The air temperature, black globe temperature, relative humidity and wind speed were observed to create the following indexes for thermal comfort: temperature-humidity index; black globe-humidity index; heat load index and the radiant thermal load. Excepted for the relative humidity, there was interaction for time × system for all variables and indexes. Interaction occurred for: air temperature at 10 a.m. and 6 p.m.; wind speed from 8 a.m. to 4 p.m.; temperature humidity index at 10 a.m. and 12 p.m.; black globe temperature, black globe humidity index, heat load index, and radiant thermal load at all the hours. During the summer, the system with shade of 28 m trees had the lowest average of black globe temperature; wind speed; black globe humidity index; radiant thermal load index; and heat load index. There was a reduction of wind speed average in systems 8 m, 18 m and 28 m trees in, respectively, 20.7; 50.0 and 48.0% in relation to no shade system; however it was not proportional to the height, with influence of the rank porosity and pantries height. Nevertheless, for radiant thermal load index the reduction was proportional to the height of the trees with 10.24; 12.49 and 20.76%, respectively, for 8 m, 18 m and 28 meters of height. There was a reduction of the thermal stress in the environment due to the presence of trees, being the heat load index thermal the index that better demonstrated the effect, despite of not being proportional to the rank height.

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