scholarly journals Evaluating Temperature Measurements of the iMET-XQ, in the Field, under Varying Atmospheric Conditions

Atmosphere ◽  
2020 ◽  
Vol 11 (4) ◽  
pp. 335 ◽  
Author(s):  
Sytske K. Kimball ◽  
Carlos J. Montalvo ◽  
Madhuri S. Mulekar
Keyword(s):  
Wind Speed ◽  
Solar Radiation ◽  
Aluminum Coating ◽  
Temperature Measurements ◽  
Atmospheric Conditions ◽  
Radiation Shield ◽  
Wind Speeds ◽  
Outdoor Setting ◽  
Accurate Temperature ◽  
Reference Sensor

Temperature measurements of InterMET Inc. aluminum-coated iMET-XQ sensors were tested in an outdoor setting under a variety of solar radiation and wind speed conditions. Twelve unshielded sensors were mounted side-by-side on the tower of a South Alabama Mesonet weather station next to a reference sensor on the tower. The iMET-XQ temperatures were most precise and accurate in solar radiation values that were close to zero, regardless of wind speed. Under overcast conditions, wind speeds of 2 m s−1 were sufficient to obtain precise and accurate temperature measurements. During the day-time, aspiration of wind speeds higher than or equal to 3 m s−1 is sufficient. An iMET-XQ was placed in a radiation shield next to the tower reference sensor to test the need for a radiation shield. A second iMET-XQ was placed unshielded on the tower. The iMET-XQ sensors with aluminum coating do not need to be shielded, but they do need to be aspirated. It is recommended that, when taking temperature measurements using unmanned aerial vehicles (UAV) with iMET-XQ sensors, the UAV either fly at 3 m s−1, be embedded in winds of those speeds, or to use the propeller wash of the UAV to aspirate the sensors.

Effects of solar radiation and wind speed on metabolic heat production by two mammals with contrasting coat colours.

1995 ◽  
Vol 198 (7) ◽  
pp. 1499-1507 ◽  
Author(s):  
G E Walsberg ◽  
B O Wolf
Keyword(s):  
Wind Speed ◽  
Solar Radiation ◽  
Heat Production ◽  
Metabolic Heat Production ◽  
Heat Gain ◽  
Solar Heat ◽  
Wind Speeds ◽  
Convective Heat Loss ◽  
Metabolic Heat ◽  
Solar Heat Gain

We report the first empirical data describing the interactive effects of simultaneous changes in irradiance and convection on energy expenditure by live mammals. Whole-animal rates of solar heat gain and convective heat loss were measured for representatives of two ground squirrel species, Spermophilus lateralis and Spermophilus saturatus, that contrast in coloration. Radiative heat gain was quantified as the decrease in metabolic heat production caused by the animal's exposure to simulated solar radiation. Changes in convective heat loss were quantified as the variation in metabolic heat production caused by changes in wind speed. For both species, exposure to 780 W m-2 of simulated solar radiation significantly reduced metabolic heat production at all wind speeds measured. Reductions were greatest at lower wind speeds, reaching 42% in S. lateralis and 29% in S. saturatus. Solar heat gain, expressed per unit body surface area, did not differ significantly between the two species. This heat gain equalled 14-21% of the radiant energy intercepted by S. lateralis and 18-22% of that intercepted by S. saturatus. Body resistance, an index of animal insulation, declined by only 10% in S. saturatus and 13% in S. lateralis as wind speed increased from 0.5 to 4.0 ms-1. These data demonstrate that solar heat gain can be essentially constant, despite marked differences in animal coloration, and that variable exposure to wind and sunlight can have important consequences for both thermoregulatory stress experienced by animals and their patterns of energy allocation.

scholarly journals Validation of Dual-Doppler Wind Profiles with in situ Anemometry

2015 ◽  
Vol 32 (5) ◽  
pp. 943-960 ◽  
Author(s):  
W. Scott Gunter ◽  
John L. Schroeder ◽  
Brian D. Hirth
Keyword(s):  
High Resolution ◽  
Wind Speed ◽  
Doppler Radar ◽  
Heavy Precipitation ◽  
Atmospheric Conditions ◽  
Wind Speeds ◽  
Time Histories ◽  
Mean Wind Speed ◽  
Wind Profiles

AbstractTypical methods used to acquire wind profiles from Doppler radar measurements rely on plan position indicator (PPI) scans being performed at multiple elevation angles to utilize the velocity–azimuth display technique or to construct dual-Doppler synthesis. These techniques, as well as those employed by wind profilers, often produce wind profiles that lack the spatial or temporal resolution to resolve finescale features. If two radars perform range–height indicator (RHI) scans (constant azimuth, multiple elevations) along azimuths separated by approximately 90°, then the intersection of the coordinated RHI planes represents a vertical set of points where dual-Doppler wind syntheses are possible and wind speed and direction profiles can be retrieved. This method also allows for the generation of high-resolution wind time histories that can be compared to anemometer time histories. This study focuses on the use of the coordinated RHI scanning strategy by two high-resolution mobile Doppler radars in close proximity to a 200-m instrumented tower. In one of the first high-resolution, long-duration comparisons of dual-Doppler wind synthesis with in situ anemometry, the mean and turbulence states of the wind measured by each platform were compared in varying atmospheric conditions. Examination of mean wind speed and direction profiles in both clear-air (nonprecipitating) and precipitating environments revealed excellent agreement above approximately 50 m. Below this level, dual-Doppler wind speeds were still good but slightly overestimated as compared to the anemometer-measured wind speeds in heavy precipitation. Bulk turbulence parameters were also slightly underestimated by the dual-Doppler syntheses.

A Comparative Study of ASOS and USCRN Temperature Measurements

2005 ◽  
Vol 22 (6) ◽  
pp. 679-686 ◽  
Author(s):  
Bomin Sun ◽  
C. Bruce Baker ◽  
Thomas R. Karl ◽  
Malcolm D. Gifford
Keyword(s):  
Wind Speed ◽  
Solar Radiation ◽  
Local Heating ◽  
Ambient Air ◽  
Local Effect ◽  
Temperature Measurements ◽  
Reference Network ◽  
Shield Effectiveness ◽  
Average Difference ◽  
Bias Analysis

Abstract Temperature measurements from the U.S. Climate Reference Network (USCRN) instrument system were compared to the Automated Surface Observing System (ASOS) ambient air temperature measurements and were examined under different regimes of wind speed and solar radiation. Influences due to observing practice differences and the effects of siting differences were discussed. This analysis indicated that the average difference between the ASOS and USCRN temperatures is on the order of 0.1°C. However, problems were noticed that were possibly related to the ASOS shield effectiveness, including a solar radiation warm effect under calm conditions and the dependence of ASOS minus USCRN temperature on wind speed. The ASOS and USCRN time of observation difference was on the order of ∼0.05°C, with a warmer ASOS daily Tmax and a cooler ASOS daily Tmin. The local effect complicates the bias analysis because it depends not only on local heating/cooling, but it can be strongly modified by cloudiness, wind, and solar radiation.

Exploring fire response to high wind speeds: fire rate of spread, energy release and flame residence time from fires burned in pine needle beds under winds up to 27 ms−1

2020 ◽  
Vol 29 (1) ◽  
pp. 81
Author(s):  
Bret Butler ◽  
Steve Quarles ◽  
Christine Standohar-Alfano ◽  
Murray Morrison ◽  
Daniel Jimenez ◽  
...  
Keyword(s):  
Wind Speed ◽  
Energy Release ◽  
Residence Time ◽  
Wildland Fire ◽  
Ground Level ◽  
Fire Spread ◽  
Convective Heating ◽  
Atmospheric Conditions ◽  
Wind Speeds ◽  
Rate Of Spread

The relationship between wildland fire spread rate and wind has been a topic of study for over a century, but few laboratory studies report measurements in controlled winds exceeding 5ms−1. In this study, measurements of fire rate of spread, flame residence time and energy release are reported for fires burning under controlled atmospheric conditions in shallow beds of pine needles subject to winds ranging from 0 to 27ms−1 (measured 5m above ground level). The data suggested that under constant flow conditions when winds are less than 10ms−1, fire rate of spread increases linearly at a rate of ~3% of the wind speed, which generally agrees with other laboratory-based models. When wind speed exceeds 10ms−1, the fire rate of spread response to wind remains linear but with a much stronger dependence, spreading at a rate of ~13% of the wind speed. Radiative and convective heating correlated directly to wind speed, with radiant heating increasing approximately three-fold as much as convective heating over the range of winds explored. The data suggested that residence time is inversely related to wind speed and appeared to approach a lower limit of ~20s as wind exceeded 15ms−1. Average flame residence time over the range of wind speeds was nominally 26s.

scholarly journals Comparative Analysis of Danger Zone Ranges Determined for LNG in the Coastal Area

2018 ◽  
Vol 1 (1) ◽  
pp. 829-834
Author(s):  
Agnieszka Kalbarczyk-Jedynak ◽  
Dorota Stochła ◽  
Marek Patsch
Keyword(s):  
Wind Speed ◽  
Coastal Area ◽  
Human Life ◽  
Weather Conditions ◽  
Atmospheric Conditions ◽  
Wind Force ◽  
Danger Zone ◽  
Wind Speeds ◽  
Variable Wind ◽  
Neutral Conditions

Abstract The analysis of danger zone ranges for LNG in the coastal area is an important task on account of, inter alia, the safety of human life. It is not an easy process, which is why we consider an danger situation for various weather conditions in the function of constant wind speeds and for various wind speeds in constant weather stability. Pasquill weather stability scale and Beaufort scale with regard to terrain roughness were adopted for the analysis. Both scenarios were considered in the example of Q-flex type vessels in the Świnoujście terminal for two methods of LNG release, i.e. related to a sudden explosion and slow release caused by a leak. The analysis was conducted and considered for the values in the top and bottom flammability limit. Modelling of the danger zone range was analysed with DNV PHAST software, version 7.11. In the process of comparison of the situation related to the risk of explosion in the function of various weather stabilities according to Pasquill scale and constant wind speeds, the values of 1.5 m/s and 5 m/s were adopted, corresponding to 1 and 3 wind force on the Beaufort scale. Those speeds correspond to the water conditions featuring tiny ripples and small waves, the crests of which start to break. The adopted weather stabilities analysed for wind speed equal to 1.5 m/s are A, B, D. A-type stability signifies the least stable atmospheric conditions, and D-type means neutral conditions. In turn, for the wind speed of 5 m/s B, D and F parameters in Pasquill scale were selected. Furthermore, ranges for variable wind speed values were analysed for the selected Pasquill stability.

scholarly journals Effects of complex radiative and convective environments on the thermal biology of the white-crowned sparrow (Zonotrichia leucophrys gambelii)

2000 ◽  
Vol 203 (4) ◽  
pp. 803-811 ◽  
Author(s):  
B.O. Wolf ◽  
K.M. Wooden ◽  
G.E. Walsberg
Keyword(s):  
Wind Speed ◽  
Solar Radiation ◽  
Air Temperature ◽  
Heat Production ◽  
Heat Balance ◽  
Metabolic Heat Production ◽  
Wind Speeds ◽  
Metabolic Heat ◽  
Simulated Solar Radiation ◽  
Zonotrichia Leucophrys Gambelii

The energy budgets of small endotherms are profoundly affected by characteristics of the physical environment such as wind speed, air temperature and solar radiation. Among these, solar radiation represents a potentially very large heat load to small animals and may have an important influence on their thermoregulatory metabolism and heat balance. In this investigation, we examined the interactive effects of wind speed and irradiance on body temperature, thermoregulatory metabolism and heat balance in the white-crowned sparrow (Zonotrichia leucophrys gambelii). We measured changes in metabolic heat production by exposing birds to different wind speeds (0.25, 0.5, 1.0 and 2.0 m s(−1)) and irradiance combinations (<3 W m(−2) and 936+/−11 W m(−2); mean +/− s.d.) at an air temperature of 10 degrees C. Body temperature was not affected by wind speed, but was significantly higher in animals not exposed to simulated solar radiation compared with those exposed at most wind speeds. In the absence of solar radiation, metabolic heat production was strongly affected by wind speed and increased by 30 % from 122 to 159 W m(−2) as wind speed increased from 0.25 to 2.0 m s(−1). Metabolic heat production was even more strongly influenced by wind speed in the presence of simulated solar radiation and increased by 51% from 94 to 142 W m(−2) as wind speed increased from 0.25 to 2. 0 m s(−1). Solar heat gain was negatively correlated with wind speed and declined from 28 to 12 W m(−2) as wind speed increased from 0.25 to 2.0 m s(−1) and, at its maximum, equaled 11% of the radiation intercepted by the animal. The overall thermal impact of the various wind speed and irradiance combinations on the animal's heat balance was examined for each treatment. Under cold conditions, with no solar radiation present, an increase in wind speed from 0.25 to 2.0 m s(−1) was equivalent to a decrease in chamber air temperature of 12.7 degrees C. With simulated solar radiation present, a similar increase in wind speed was equivalent to a decrease in chamber air temperature of 16 degrees C. Overall, shifting environmental conditions from a wind speed of 0.25 m s(−1) and irradiance of 936 W m(−2) to a wind speed of 2.0 m s(−1) with no short-wave radiation present was equivalent to decreasing chamber air temperature by approximately 20 degrees C. The sensitivity to changes in the convective environment, combined with the complex effects of changes in irradiance levels revealed by re-analyzing data published previously, significantly complicates the task of estimating the heat balance of animals in nature.

Measuring Sub-second Wind Velocity Changes for Agricultural Drift One Meter Above the Ground

2019 ◽  
Vol 35 (5) ◽  
pp. 697-704
Author(s):  
Matthew W. Schramm ◽  
H Mark Hanna ◽  
Matt J. Darr ◽  
Steven J. Hoff ◽  
Brian L. Steward
Keyword(s):  
Wind Speed ◽  
Solar Radiation ◽  
Wind Velocity ◽  
Wind Direction ◽  
Weather Conditions ◽  
Spray Drift ◽  
Average Wind Speed ◽  
Wind Speeds ◽  
Average Wind ◽  
Velocity Changes

Abstract. Agricultural spray drift is affected by many factors including current weather conditions, topography of the surrounding area, fluid properties at the nozzle, and the height at which the spray is released. During the late spring/summer spray seasons of 2014 and 2015, wind direction, speed, and solar radiation (2014 only) were measured at 10 Hz, 1 m above the ground to investigate conditions that are typically encountered by a droplet when released from a nozzle on an agricultural sprayer. Measurements of wind velocity as the wind passed from an upwind sensor to a downwind sensor were used to evaluate what conditions wind may be most likely to have a significant direction or speed change which affects droplet trajectory. For two individual datasets in which the average wind speed was 3.6 and 1.5 m/s (8.0 and 3.4 mi/h), there exists little linear correlation of wind speed or wind direction between an upwind and downwind anemometer separated by 30.5 m (100 ft). The highest observed correlation, resulting from a 12-s lag between the upwind and downwind datasets, was 0.29 when the average wind speed was 3.6 m/s (8.0 mi/h). Correlations greater than 0.1 were only found for wind speeds exceeding 3 m/s. Using this lag time, it was observed that the wind direction 30 s into the future had a 30% chance to be different by more than 20° from current conditions. A wind speed difference of more than 1 m/s (2.2 mi/h) from current conditions [mean wind speed was 3.6 m/s (8.0 mi/h)] was observed about 50% of the time. Analyzing 36 days of the 2014 and 2015 spray season wind velocity data showed that the most variability in wind direction occurred with wind speeds below 2 m/s (4.5 mi/h). Greater wind direction variability occurred in the mid-afternoon with higher solar radiation. Keywords: Sprayers, Spray drift, Spray droplets, Turbulence, Wind effects.

SHAPING OF AN AUTONOMOUS POWER SYSTEM FOR GUARANTEED POWER SUPPLY WITH THE PREDOMINANCE WIND ENERGY

2018 ◽  
pp. 28-50
Author(s):  
S. G. Ignatiev ◽  
S. V. Kiseleva
Keyword(s):  
Energy Storage ◽  
Wind Speed ◽  
Wind Energy ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Energy Demand ◽  
Diesel Generator ◽  
Average Wind Speed ◽  
Wind Speeds ◽  
Average Wind

Optimization of the autonomous wind-diesel plants composition and of their power for guaranteed energy supply, despite the long history of research, the diversity of approaches and methods, is an urgent problem. In this paper, a detailed analysis of the wind energy characteristics is proposed to shape an autonomous power system for a guaranteed power supply with predominance wind energy. The analysis was carried out on the basis of wind speed measurements in the south of the European part of Russia during 8 months at different heights with a discreteness of 10 minutes. As a result, we have obtained a sequence of average daily wind speeds and the sequences constructed by arbitrary variations in the distribution of average daily wind speeds in this interval. These sequences have been used to calculate energy balances in systems (wind turbines + diesel generator + consumer with constant and limited daily energy demand) and (wind turbines + diesel generator + consumer with constant and limited daily energy demand + energy storage). In order to maximize the use of wind energy, the wind turbine integrally for the period in question is assumed to produce the required amount of energy. For the generality of consideration, we have introduced the relative values of the required energy, relative energy produced by the wind turbine and the diesel generator and relative storage capacity by normalizing them to the swept area of the wind wheel. The paper shows the effect of the average wind speed over the period on the energy characteristics of the system (wind turbine + diesel generator + consumer). It was found that the wind turbine energy produced, wind turbine energy used by the consumer, fuel consumption, and fuel economy depend (close to cubic dependence) upon the specified average wind speed. It was found that, for the same system with a limited amount of required energy and high average wind speed over the period, the wind turbines with lower generator power and smaller wind wheel radius use wind energy more efficiently than the wind turbines with higher generator power and larger wind wheel radius at less average wind speed. For the system (wind turbine + diesel generator + energy storage + consumer) with increasing average speed for a given amount of energy required, which in general is covered by the energy production of wind turbines for the period, the maximum size capacity of the storage device decreases. With decreasing the energy storage capacity, the influence of the random nature of the change in wind speed decreases, and at some values of the relative capacity, it can be neglected.

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