Evaluation of similarity scales in the stratified surface layer using wind speed and temperature gradient

Abstract Widely used numerical models to estimate turbulent exchange of latent heat flux (LE) and sensible heat flux H across the water–atmosphere interface are based on the bulk transfer relations linked indirectly to atmospheric stability, even though the accurate prediction of the influence of stability on fluxes is uncertain. Here eddy covariance data collected over the water surface of Ross Barnett Reservoir, Mississippi, was analyzed to study how atmospheric stability and other variables (wind speed, vapor pressure gradient, and temperature gradient) in the atmospheric surface layer (ASL) modulated LE and H variations in different stability ranges. LE and H showed right-skewed, bell-shaped distributions as the ASL stability shifted from very unstable to near neutral and then stable conditions. The results demonstrate that the maximum (minimum) LE and H did not necessarily occur under the most unstable (stable) conditions, but rather in the intermediate stability ranges. No individual variables were able to explain the dependence of LE and H variations on stability. The coupling effects of stability, wind speed, and vapor pressure gradient (temperature gradient) on LE (H) primarily caused the observed variations in LE and H in different stability ranges. These results have important implications for improving parameterization schemes to estimate fluxes over water surfaces in numerical models.

Download Full-text

Dependence of Aerosol Particle Concentration in Surface Air over the Moscow Region on Wind Speed and Lapse Rate

Meteorologiya i Gidrologiya ◽

10.52002/0130-2906-2021-1-103-110 ◽

2021 ◽

pp. 103-110

Author(s):

E. A. Stulov ◽

◽

E. V. Sosnikova ◽

N. A. Monakhova ◽

◽

...

Keyword(s):

Surface Layer ◽

Wind Speed ◽

Particle Concentration ◽

Meteorological Factors ◽

Lapse Rate ◽

Radiosonde Data ◽

Vertical Temperature Gradient ◽

Vertical Temperature ◽

Simple Estimation ◽

The City

Based on the daily measurements of atmospheric aerosol characteristics in the city of Dolgoprudny (20 km from the center of Moscow) carried out during 2013-2018, the influence of some meteorological factors on the concentration of various aerosol fractions in the surface layer of the atmosphere is analyzed. It is that the aerosol concentration depends most on the wind speed and the vertical temperature gradient. The method of simple estimation of aerosol particles accumulation conditions in the surface layer based on the use of standard radiosonde data is developed.

Download Full-text

Hair density, wind speed, and heat loss in mammals

Journal of Applied Physiology ◽

10.1152/jappl.1965.20.4.796 ◽

1965 ◽

Vol 20 (4) ◽

pp. 796-801 ◽

Cited By ~ 71

Author(s):

R. T. Tregear

Keyword(s):

Wind Speed ◽

Temperature Gradient ◽

Heat Loss ◽

Thermal Insulation ◽

Hair Density ◽

Wind Speeds

The heat loss from excised pelts of rabbits, horses, and pigs has been measured at various wind speeds. The temperature gradient through the fur was also measured. The thermal insulation of fur is highly dependent on the hair density (i.e., number of hairs/ cm2), and on the wind passing over its surface. If there are less than 1,000 hairs/cm2, an 8-mph wind penetrates deep into the fur, but at higher hair densities an 18-mph wind penetrates only a little way into the fur. fur insulation; obstruction of wind by hair Submitted on September 10, 1964

Download Full-text

A Wind-Speed Anomaly in the Surface Layer in the Po Valley

Boundary-Layer Meteorology ◽

10.1007/bf03335361 ◽

1979 ◽

Vol 16 (3) ◽

pp. 131-137

Author(s):

A. Longhetto ◽

L. Briatore

Keyword(s):

Surface Layer ◽

Wind Speed ◽

Po Valley

Download Full-text

Pengaruh Angin Dan Kelembapan Atmosfer Lapisan Atas Terhadap Lapisan Permukaan Di Manado

Jurnal MIPA ◽

10.35799/jm.3.1.2014.3909 ◽

2014 ◽

Vol 3 (1) ◽

pp. 58 ◽

Cited By ~ 1

Author(s):

Farid Mufti ◽

As'ari .

Keyword(s):

Surface Layer ◽

Wind Speed ◽

Correlation Coefficient ◽

Rainy Season ◽

Primary Objective ◽

Dry Season ◽

Correlation Technique ◽

Wind Condition ◽

The North ◽

Positive Correlation Coefficient

Penelitian ini mengkaji lebih dalam kondisi angin dan kelembapan udara pada saat musim hujan dan musim kemarau di Manado dengan menggunakan data di lapisan permukaan dan data udara atas dari Stasiun Meteorologi Sam Ratulangi Manado. Tujuan utama dari penelitian ini adalah mendapatkan hubungan antara kondisi angin dan kelembapan lapisan atas terhadap lapisan permukaan, sehingga dapat memprakirakan kondisi angin dan kelembapan lapisan permukaan dengan berdasarkan keadaan lapisan atas. Metode yang digunakan adalah mengkomponenkan angin dalam arah utara-selatan dan timur-barat, selanjutnya mencari keterkaitan dengan menggunakan teknik korelasi. Hasil penelitian ini menunjukkan pada saat musim hujan angin pada lapisan 1500 m dan angin di lapisan permukaan memiliki arah yang sama dan saling menguatkan untuk komponen timur-barat (zonal) dengan koefisien korelasi r=0,56, sedangkan pada saat musim kemarau angin pada lapisan 1500 m dan angin di lapisan permukaan memiliki arah yang sama dan saling menguatkan untuk komponen utara-selatan (meridional) dengan koefisien korelasi r=0,45. Keterkaitan yang cukup kuat antara angin dengan kelembapan terjadi pada komponen V (meridional) yaitu, pada saat musim hujan, semakin besar kecepatan angin komponen negatif (utara) semakin besar pula kelembapan udara di lapisan permukaan, dengan koefisien korelasi benilai positif r=0.40. Pada saat musim kemarau, semakin besar kecepatan angin komponen positif (selatan) semakin kecil kelembapan udara di lapisan permukaan, dengan koefisien korelasi bernilai negatif r=— 0,48.This study examined the wind and humidity condition in the rainy season and dry season in Manado by using the data in surface layer and upper air data from the Sam Ratulangi Meteorological Station. The primary objective of this study was to find the relationship between wind condition and upper layer humidity to surface layer, using correlation technique, in order to predict wind condition and humidity of the surface layer based on the condition of the upper layer. The results showed that, during the rainy season, the wind at layer 1500 m and surface layer had the same direction and mutually reinforced for the east-west component (zonal) with correlation coefficient r=0.56, whereas during the dry season, wind at layer 1500 m and at surface layer had the same direction and mutually reinforced for the north-south component (meridional) with correlation coefficient r=0.45. A relationship between wind and humidity was found at V component (meridional), which was, at rainy season, the higher the wind speed of negative component (north) the higher the humidity at surface layer with positive correlation coefficient r=0.40. At dry season, the higher the wind speed of positive component (south), the lower the humidity at the surface layer, with negative correlation coefficient r=—0.48.

Download Full-text

WRF Model Experiments on the Antarctic Atmosphere in Winter

Monthly Weather Review ◽

10.1175/2010mwr3478.1 ◽

2011 ◽

Vol 139 (4) ◽

pp. 1279-1291 ◽

Cited By ~ 23

Author(s):

Esa-Matti Tastula ◽

Timo Vihma

Keyword(s):

Boundary Layer ◽

Surface Layer ◽

Wind Speed ◽

Surface Pressure ◽

Mesoscale Model ◽

Wrf Model ◽

Radiative Transfer Model ◽

Transfer Model ◽

Temperature Bias ◽

Radiation Parameterizations

Abstract The standard and polar versions 3.1.1 of the Weather Research and Forecasting (WRF) model, both initialized by the 40-yr ECMWF Re-Analysis (ERA-40), were run in Antarctica for July 1998. Four different boundary layer–surface layer–radiation scheme combinations were used in the standard WRF. The model results were validated against observations of the 2-m temperature, surface pressure, and 10-m wind speed at 9 coastal and 2 inland stations. The best choice for boundary layer and radiation parameterizations of the standard WRF turned out to be the Yonsei University boundary layer scheme in conjunction with the fifth-generation Pennsylvania State University–National Center for Atmospheric Research Mesoscale Model (MM5) surface layer scheme and the Rapid Radiative Transfer Model for longwave radiation. The respective temperature bias was on the order of 3°C less than the biases obtained with the other combinations. Increasing the minimum value for eddy diffusivity did, however, improve the performance of the asymmetric convective scheme by 0.8°C. Averaged over the 11 stations, the error growths in 24-h forecasts were almost identical for the standard and Polar WRF, but in 9-day forecasts Polar WRF gave a smaller 2-m temperature bias. For the Vostok station, however, the standard WRF gave a less positively biased 24-h temperature forecast. On average, the polar version gave the least biased surface pressure simulation. The wind speed simulation was characterized by low correlation values, especially under weak winds and for stations surrounded by complex topography.

Download Full-text

Influence of Cowl on the Spatial Distribution of Oxygen in Semi-Aerobic Landfill

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.518-523.3391 ◽

2012 ◽

Vol 518-523 ◽

pp. 3391-3395

Author(s):

Ling Zhao ◽

Chao Zhao

Keyword(s):

Surface Layer ◽

Spatial Distribution ◽

Wind Speed ◽

Flow Rate ◽

Air Flow Rate ◽

Wind Speeds ◽

Aerobic Landfills ◽

Different Climates ◽

Oxygen Transmission ◽

Oxygen Concentrations

To elevate the air flow rate in vent pipes of semi-aerobic landfill, promote oxygen transmit into waste and methane mitigation, a wind-driven cowl was fixed on one of the two semi-aerobic landfills’ vent pipe. With the aim of figuring out the influence of cowl on the spatial distribution of oxygen under different climates, wind speeds were set at 3 m/s, 5 m/s, 7 m/s and 0 m/s sequentially. Oxygen concentrations and temperatures were recorded once a week. Data from experimental results indicated that oxygen concentrations went up along with the height above the bottom of landfill after deducting the oxygen transported by leachate collection pipes. Average oxygen concentrations except the surface layer were 3.5%, 4.2%, 3.8%, 3.0% for S-A with cowl and 2.9%, 3.4%, 3.7%, 3.0% for S-A under the wind speeds of 3 m/s, 5 m/s, 7 m/s, 0 m/s, respectively. Meantime, the aerobic radius in S-A with cowl were 0.84 m, 1.01 m, 0.87 m, 0.62 m and 0.76 m, 0.84 m, 0.87 m, 0.65 m in S-A. The effect of the cowl on oxygen transmission maximized at the wind speed of 5 m/s. It is clearly that wind energy can be better used on enhancing the ventilation in vent pipe and expanding aerobic radius after application of cowl.

Download Full-text