scholarly journals Low Temperate Zone Sporadic-E: Seasonal and Diurnal Variations at Rarotonga

1986 ◽  
Vol 39 (3) ◽  
pp. 401
Author(s):  
WJ Baggaley
Keyword(s):  
Large Deviations ◽  
Local Time ◽  
Seasonal Variations ◽  
Diurnal Variations ◽  
Formation Processes ◽  
Seasonal Characteristics ◽  
The Pacific ◽  
Seasonal And Diurnal Variations ◽  
Sporadic E ◽  
Diurnal Period

The seasonal variations of strong E s occurrence as a function of diurnal period have been obtained for the Pacific station of Rarotonga (21 0 .2 S). The seasonal characteristics depend markedly on local time with afternoon Es activity showing large deviations-equinoxial enhancements and summer peaks occurring before solstice-from those expected from the formation processes currently understood.

scholarly journals Seasonal and Diurnal Variations of Ozone near the Mesopause from Observations of the 11.072-GHz Line

2009 ◽  
Vol 26 (10) ◽  
pp. 2192-2199 ◽  
Author(s):  
A. E. E. Rogers ◽  
M. Lekberg ◽  
P. Pratap
Keyword(s):  
Seasonal Variation ◽  
Seasonal Variations ◽  
Atomic Hydrogen ◽  
Diurnal Variations ◽  
Mixing Ratio ◽  
Mesopause Region ◽  
Mixing Ratios ◽  
Rates Of Change ◽  
Broadband Emission ◽  
Seasonal And Diurnal Variations

Abstract Ground-based observations of the 11.072-GHz line of ozone were made from January 2008 through January 2009. These observations provide an estimate of the diurnal and seasonal variations of ozone in the mesopause region. The 11-GHz line is more sensitive to the ozone at higher altitudes than ground observations of the 142-GHz line, because of the reduced Doppler line width. The observations show an increase in the volume mixing ratio of ozone above 80 km at night by more than a factor of 10 and a seasonal variation of about a factor of 2, which is consistent with the semiannual variations of atomic hydrogen in the mesopause region. The diurnal amplitude and rates of change of the mixing ratios at sunrise and sunset are compared with ground-based observations of the 142-GHz line and the observations of the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument on the Thermosphere, Ionosphere, Mesosphere, Energetics and Dynamics (TIMED) satellite, as well as with a simplified chemical model of the creation and destruction of ozone in the mesopause region.

Particulate Matter Concentrations and Emission Rates at Two Retrofitted Manure-Belt Layer Houses

2021 ◽  
Vol 64 (3) ◽  
pp. 829-841
Author(s):  
Reyna M. Knight ◽  
Xinjie Tong ◽  
Lingying Zhao ◽  
Roderick B. Manuzon ◽  
Matthew J. Darr ◽  
...  
Keyword(s):  
Particulate Matter ◽  
Ambient Temperature ◽  
Seasonal Variations ◽  
Egg Production ◽  
Ventilation Rate ◽  
Diurnal Variations ◽  
List Type ◽  
Emission Rates ◽  
Annual Average ◽  
Seasonal And Diurnal Variations

HighlightsAnnual average PM10 (daily) and PM2.5 (hourly) concentrations of 509 ±203 and 43.3 ±36.1 µg m-3, respectively.Significant seasonal and diurnal variations in PM concentrations; higher in colder seasons and during daytime.Annual average PM10 (daily) and PM2.5 (hourly) emission rates of 17.9 ±9.6 and 1.41 ±1.53 mg d-1 hen-1, respectively.Significant diurnal variations in PM emission rates but inconsistent seasonal variations; higher during daytime.Abstract. Particulate matter (PM) concentration and emission rate information is needed to assess air quality concerns and environmental impacts related to egg production. Many egg layer buildings were retrofitted from high-rise to manure-belt houses over the past few decades. However, no studies have reported these PM data for the retrofitted layer houses. In this study, concentrations and emission rates of PM10 and PM2.5 were continuously monitored for 12 months at two commercial retrofitted manure-belt layer houses in the Midwestern U.S. The average daily mean PM10 and average hourly mean PM2.5 concentrations in the houses were 509 ±203 µg m-3 and 43.3 ±36.1 µg m-3, respectively. Significant seasonal and diurnal variations in PM concentrations were observed, with higher concentrations in colder seasons and during daytime. The average daily mean PM10 and average hourly mean PM2.5 emission rates from the two houses were 17.9 ±9.6 mg d-1 hen-1 and 1.41 ±1.53 mg d-1 hen-1, respectively. There were no consistent patterns in seasonal variations. Significant diurnal variations were also observed for PM emission rates, with higher PM emission rates observed during daytime. The PM concentrations were significantly correlated with ambient temperature, ventilation rate, bird age, egg production, daily mortality, and feed conversion ratio, while PM emission rates were significantly correlated with ambient temperature, bird age, bird mass, egg mass, and ventilation rate. Keywords: Diurnal variation, Dust, Egg production, PM, Poultry, Seasonal variation.

scholarly journals Seasonal and diurnal variations of black carbon and organic carbon aerosols in Bangkok

2011 ◽  
Vol 116 (D15) ◽  
Author(s):  
L. K. Sahu ◽  
Y. Kondo ◽  
Y. Miyazaki ◽  
Prapat Pongkiatkul ◽  
N. T. Kim Oanh
Keyword(s):  
Organic Carbon ◽  
Black Carbon ◽  
Diurnal Variations ◽  
Seasonal And Diurnal Variations ◽  
Carbon Aerosols

scholarly journals Mars Global Ionosphere-Thermosphere Model: Solar cycle, seasonal, and diurnal variations of the Mars upper atmosphere

2015 ◽  
Vol 120 (2) ◽  
pp. 311-342 ◽  
Author(s):  
S. W. Bougher ◽  
D. Pawlowski ◽  
J. M. Bell ◽  
S. Nelli ◽  
T. McDunn ◽  
...  
Keyword(s):  
Solar Cycle ◽  
Diurnal Variations ◽  
Upper Atmosphere ◽  
Seasonal And Diurnal Variations

scholarly journals Seasonal and diurnal variations in moisture, heat and CO2 fluxes over a typical steppe prairie in Inner Mongolia, China

2009 ◽  
Vol 13 (7) ◽  
pp. 987-998 ◽  
Author(s):  
Z. Gao ◽  
D. H. Lenschow ◽  
Z. He ◽  
M. Zhou
Keyword(s):  
Inner Mongolia ◽  
Surface Albedo ◽  
Sensible Heat Flux ◽  
Experimental Period ◽  
Diurnal Variations ◽  
Heat Fluxes ◽  
Co2 Fluxes ◽  
Sensible Heat ◽  
Eddy Covariance Method ◽  
Seasonal And Diurnal Variations

Abstract. In order to examine energy partitioning and CO2 exchange over a steppe prairie in Inner Mongolia, China, fluxes of moisture, heat and CO2 in the surface layer from June 2007 through June 2008 were calculated using the eddy covariance method. The study site was homogenous and approximately 1500 m×1500 m in size. Seasonal and diurnal variations in radiation components, energy components and CO2 fluxes are examined. Results show that all four radiation components changed seasonally, resulting in a seasonal variation in net radiation. The radiation components also changed diurnally. Winter surface albedo was higher than summer surface albedo because during winter the snow-covered surface increased the surface albedo. The seasonal variations in both sensible heat and CO2 fluxes were stronger than those of latent heat and soil heat fluxes. Sensible heat flux was the main consumer of available energy for the entire experimental period. The energy imbalance problem was encountered and the causes are analyzed.

scholarly journals Temperature decadal trends, and their relation to diurnal variations in the lower thermosphere, stratosphere, and mesosphere, based on measurements from SABER on TIMED

2021 ◽  
Vol 39 (2) ◽  
pp. 327-339
Author(s):  
Frank T. Huang ◽  
Hans G. Mayr
Keyword(s):  
Local Time ◽  
Lower Thermosphere ◽  
3D Models ◽  
Diurnal Variations ◽  
Local Times ◽  
Temperature Trends ◽  
Microwave Sounding Unit ◽  
Lidar Measurements ◽  
Microwave Sounding ◽  
Thermal Tides

Abstract. We have derived the behavior of decadal temperature trends over the 24 h of local time, based on zonal averages of SABER data, for the years 2012 to 2014, from 20 to 100 km, within 48∘ of the Equator. Similar results have not been available previously. We find that the temperature trends, based on zonal mean measurements at a fixed local time, can be different from those based on measurements made at a different fixed local time. The trends can vary significantly in local time, even from hour to hour. This agrees with some findings based on nighttime lidar measurements. This knowledge is relevant because the large majority of temperature measurements, especially in the stratosphere, are made by instruments on sun-synchronous operational satellites which measure at only one or two fixed local times, for the duration of their missions. In these cases, the zonal mean trends derived from various satellite data are tied to the specific local times at which each instrument samples the data, and the trends are then also biased by the local time. Consequently, care is needed in comparing trends based on various measurements with each other, unless the data are all measured at the same local time. Similar caution is needed when comparing with models, since the zonal means from 3D models reflect averages over both longitude and the 24 h of local time. Consideration is also needed in merging data from various sources to produce generic, continuous, longer-term records. Diurnal variations of temperature themselves, in the form of thermal tides, are well known and are due to absorption of solar radiation. We find that at least part of the reason that temperature trends are different for different local times is that the amplitudes and phases of the tides themselves follow trends over the same time span of the data. Many of the past efforts have focused on the temperature values with local time when merging data from various sources and on the effect of unintended satellite orbital drifts, which result in drifting local times at which the temperatures are measured. However, the effect of local time on trends has not been well researched. We also derive estimates of trends by simulating the drift of local time due to drifting orbits. Our comparisons with results found by others (Advanced Microwave Sounding Unit, AMSU; lidar) are favorable and informative. They may explain, at least in part, the bridge between results based on daytime AMSU data and nighttime lidar measurements. However, these examples do not form a pattern, and more comparisons and study are needed.

scholarly journals Diurnal and Seasonal Variations of Surface Energy and CO2 Fluxes over a Site in Western Tibetan Plateau

Atmosphere ◽  
2020 ◽  
Vol 11 (3) ◽  
pp. 260 ◽  
Author(s):  
Xingbing Zhao ◽  
Changwei Liu ◽  
Nan Yang ◽  
Yubin Li
Keyword(s):  
Heat Flux ◽  
Energy Balance ◽  
Tibetan Plateau ◽  
Surface Energy ◽  
Seasonal Variations ◽  
Surface Energy Balance ◽  
Diurnal Variations ◽  
Heat Fluxes ◽  
Co2 Fluxes ◽  
Western Tibetan Plateau

Land surface process observations in the western Tibet Plateau (TP) are limited because of the abominable natural conditions. During the field campaign of the Third Tibetan Plateau Atmospheric Scientific Experiment (TIPEX III), continuous measurements on the four radiation fluxes (downward/upward short/long-wave radiations), three heat fluxes (turbulent sensible/latent heat fluxes and soil heat flux) and also CO2 flux were collected from June 2015 through January 2017 at Shiquanhe (32.50° N, 80.08° E, 4279.3 m above sea level) in the western Tibetan Plateau. Diurnal and seasonal variation characteristics of these surface energy and CO2 fluxes were presented and analyzed in this study. Results show that (1) diurnal variations of the seven energy fluxes were found with different magnitudes, (2) seasonal variations appeared for the seven energy fluxes with their maxima in summer and minima in winter, (3) diurnal and seasonal variations of respiration caused by the biological and chemical processes within the soil were found, and absorption (release) of CO2 around 0.1 mg m−2 s−1 occurred at afternoon of summer (midnight of winter), but the absorption and release generally canceled out from a yearly perspective; and (4) the surface energy balance ratio went through both diurnal and seasonal cycles, and in summer months the slopes of the fitting curve were above 0.6, but in winter months they were around 0.5. Comparing the results of the Shiquanhe site with the central and eastern TP sites, it was found that (1) they all generally had similar seasonal and diurnal variations of the fluxes, (2) caused by the low rainfall quantity, latent heat flux at Shiquanhe (daily daytime mean always less than 90 W m−2) was distinctively smaller than at the central and eastern TP sites during the wet season (generally larger than 100 W m−2), and (3) affected by various factors, the residual energy was comparatively larger at Shiquanhe, which led to a small surface energy balance ratio.

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