scholarly journals One-year aerosol profiling with EUCAARI Raman lidar at Shangdianzi GAW station: Beijing plume and seasonal variations

2012 ◽  
Vol 117 (D13) ◽  
pp. n/a-n/a ◽  
Author(s):  
A. Hänel ◽  
H. Baars ◽  
D. Althausen ◽  
A. Ansmann ◽  
R. Engelmann ◽  
...  
Keyword(s):  
Seasonal Variations ◽  
Raman Lidar ◽  
One Year

Twilight observations of upper atmospheric sodium, potassium, and lithium

1969 ◽  
Vol 47 (1) ◽  
pp. 85-98 ◽  
Author(s):  
W. A. Gault ◽  
H. N. Rundle
Keyword(s):  
Density Distribution ◽  
Seasonal Variations ◽  
Resonance Line ◽  
Lower Layer ◽  
Atmospheric Transmission ◽  
Sodium Potassium ◽  
Sodium Layer ◽  
Lower Height ◽  
One Year

Twilight resonance emissions due to atmospheric sodium, lithium, and potassium have been measured for over one year. The existence of the potassium resonance line was verified by using an absorption cell.Several problems of measuring the emissions and of subsequently calculating a density distribution are discussed. The widths of about 13 km and the topside scale heights of about 4.5 km obtained for the sodium layer are significantly less than obtained at Saskatoon in previous measurements. Atmospheric transmission functions have been recalculated with the results that the sodium and lithium layers are both at about the same height of around 90 km. A lower height of about 85 km was obtained for the potassium layer.The seasonal variations of sodium and lithium twilight abundances are shown to be similar with additional sharp enhancements of lithium abundances thought to be due to natural and man-made injections of lithium. Any seasonal variations of the potassium abundances in the lower layer were masked by large day-to-day fluctuations.

Characterization of dust aerosol over United Arab Emirates

2020 ◽  
Author(s):  
Mika Komppula ◽  
Maria Filioglou ◽  
Xiaoxia Shang ◽  
Eleni Giannakaki ◽  
Anne Hirsikko ◽  
...  
Keyword(s):  
United Arab Emirates ◽  
Mineral Dust ◽  
Raman Lidar ◽  
Study Region ◽  
Water Vapour Concentration ◽  
Western Asia ◽  
Dust Events ◽  
One Year ◽  
The One ◽  
Depolarization Ratios

<p>One-year of ground-based Raman lidar observations have been conducted in order to characterize the aerosol properties over United Arab Emirates (UAE). In total, over 1000 aerosol layers were detected during the one-year campaign period which was carried between March 2018 and February 2019. We found that the measurement site is a receptor of frequent dust events but predominantly the dust is mixed with anthropogenic and/or aerosol of marine origin. With our multiwavelength PollyXT Raman lidar we are able to retrieve the backscatter coefficients (at 355, 532 and 1064 nm), extinction coefficients (at 387 and 607nm), particle depolarization ratios (at 355 and 532 nm), water vapour concentration (at 407 nm), and further on lidar ratios and Ångström exponents to characterize the aerosols properties in detail. In general, the average lidar ratios and linear particle depolarization ratios already showed strong presence of dust aerosols. Since the region is both a source and a receptor of mineral dust, we have also explored the pure mineral dust properties in the region. The findings suggest that the mineral dust properties over the Middle East and western Asia, including the observation site, are comparable to those of the African mineral dust regarding the particle depolarization ratios but not the lidar ratios. The lower lidar ratio values are attributed to different geochemical characteristics of the under-study region compared to soil originating from Northern Africa.</p>

scholarly journals Tropospheric water vapour and relative humidity profiles from lidar and microwave radiometry

2013 ◽  
Vol 6 (6) ◽  
pp. 10481-10510
Author(s):  
F. Navas-Guzmán ◽  
J. Fernández-Gálvez ◽  
M. J. Granados-Muñoz ◽  
J. L. Guerrero-Rascado ◽  
J. A. Bravo-Aranda ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Water Vapour ◽  
Microwave Radiometer ◽  
Radiosonde Data ◽  
Mixing Ratio ◽  
Raman Lidar ◽  
New Approach ◽  
Lidar Measurements ◽  
One Year ◽  
Humidity Profiles

Abstract. In this paper, we outline an iterative method to calibrate the water vapour mixing ratio profiles retrieved from Raman lidar measurements. Simultaneous and co-located radiosonde data are used for this purpose and the calibration results obtained during a radiosonde campaign performed in Summer and Autumn 2011 are presented. The water vapour profiles measured during nighttime by the Raman lidar and radiosondes are compared and the differences between the methodologies are discussed. Moreover, a new approach to obtain relative humidity profiles by combination of simultaneous profiles of temperature (retrieved from a microwave radiometer) and water vapour mixing ratio (from a Raman lidar) is addressed. In the last part of this work, a statistical analysis of water vapour mixing ratio and relative humidity profiles obtained during one year of simultaneous measurements is presented.

scholarly journals Ekološki otisak cestovnog prometa na cresko-lošinjskom arhipelagu

Geoadria ◽  
2017 ◽  
Vol 15 (2) ◽  
pp. 269
Author(s):  
Hrvoje Grofelnik
Keyword(s):  
Seasonal Variations ◽  
Co2 Emission ◽  
Road Traffic ◽  
Dominant Role ◽  
Point Of View ◽  
Co2 Absorption ◽  
Northern Adriatic ◽  
Open Sea ◽  
One Year

Cres-Lošinj Archipelago is the largest insular traffic unit in Northern Adriatic. The archipelago consists of two large islands, Cres and Lošinj, and 27 smaller islands located among Kvarner, Kvarnerić, Rijeka Bay and open sea. From the point of view of traffic, this area gravitates mostly toward Rijeka traffic node. Traffic development of the islands was determined in the second half of the 20th century with the development of ferry traffic and road traffic on the islands. Today, the Archipelago is characterized by prominent seasonal variations of road traffic intensity due to dominant role of tourism in space valorisation. This research included partial determination of Ecological Footprint of road traffic on the islands on the basis of CO2 emission and capacity of insular surfaces to absorb CO2 .The author also created a model for calculating road mileage on the islands and indirectly calculated CO2 emission. The results indicated significant seasonal variations of CO2  emission on the islands, which are closely related to tourist valorisation of space and the number of non-residential vehicles on the islands. The paper also provides the ratio between residential and non-residential vehicles on the island, which influence the emission in accordance with their energy efficiency. The research showed that the capacity of CO2  absorption on Cres-Lošinj Archipelago is approximately 40 times greater than CO2 emission from road traffic during one year. 

scholarly journals The IFAE/UAB Raman LIDAR for the CTA-North

2019 ◽  
Vol 197 ◽  
pp. 02005
Author(s):  
Markus Gaug ◽  
Oscar Blanch ◽  
Merve Sıdıka Çolak ◽  
Michele Doro ◽  
Lluis Font ◽  
...  
Keyword(s):  
Focal Plane ◽  
Light Guide ◽  
Aerosol Extinction ◽  
Raman Lidar ◽  
Readout System ◽  
The Status ◽  
One Year ◽  
Near Future ◽  
532 Nm ◽  
Better Than

The IFAE/UAB Raman LIDAR project aims to develop a Raman LIDAR suitable for the online atmospheric calibration of the CTA. Requirements for such a solution include the ability to characterize aerosol extinction to distances of more than 20 km with an accuracy better than 5%, within time scales of less than one minute. The Raman LIDAR consists therefore of a large 1.8 m mirror and a powerful pulsed Nd-YAG laser. A liquid light-guide collects the light at the focal plane and transports it to the readout system. An in-house built polychromator has been characterized thoroughly with respect to its capability to separate effciently the different wavelengths (355 nm, 387 nm, 532 nm and 607 nm). It was found to operate according to specifications, particularly that light leakage from the elastic channels (532 nm and 355 nm) into the much dimmer Raman channels (387 nm and 607 nm) could be excluded to less than 2 × 10-7. We present here the status of the integration and commissioning of this solution and plans for the near future. After a one-year test period at the Observatorio del Roque de los Muchachos, an in-depth evaluation of this and the solutions adopted by a similar project developed by the LUPM, Montpellier, will lead to a final Raman LIDAR proposed to be built for both CTA sites.

scholarly journals Effects of seasonal variations and collection methods on the mineral composition of propolis from Apis mellifera Linnaeus Beehives

2016 ◽  
Vol 76 (2) ◽  
pp. 396-401 ◽  
Author(s):  
E. A. Souza ◽  
R. Zaluski ◽  
N. Veiga ◽  
R. O. Orsi
Keyword(s):  
Apis Mellifera ◽  
Mineral Composition ◽  
Seasonal Variations ◽  
Atomic Absorption Spectrophotometry ◽  
Mean Values ◽  
Africanized Honey Bees ◽  
Harvesting Method ◽  
The Mean ◽  
One Year ◽  
The One

Abstract The effects of seasonal variations and the methods of collection of propolis produced by Africanized honey bees Apis mellifera Linnaeus, 1758, on the composition of constituent minerals such as magnesium (Mg), zinc (Zn), iron (Fe), sodium (Na), calcium (Ca), copper (Cu), and potassium (K) were evaluated. Propolis was harvested from 25 beehives by scraping or by means of propolis collectors (screen, “intelligent” collector propolis [ICP], lateral opening of the super [LOS], and underlay method). During the one-year study, the propolis produced was harvested each month, ground, homogenized, and stored in a freezer at -10 ºC. Seasonal analyses of the mineral composition were carried out by atomic absorption spectrophotometry and the results were evaluated by analysis of variance (ANOVA), followed by Tukey-Kramer’s test to compare the mean values (p<0.05). The results showed that seasonal variations influence the contents of 5 minerals (Mg, Fe, Na, Ca, and Cu), and the propolis harvesting method affects the contents of 4 minerals (Mg, Zn, Fe, and Ca).

scholarly journals Technical Note: One year of Raman-lidar measurements in Gual Pahari EUCAARI site close to New Delhi in India – Seasonal characteristics of the aerosol vertical structure

2012 ◽  
Vol 12 (10) ◽  
pp. 4513-4524 ◽  
Author(s):  
M. Komppula ◽  
T. Mielonen ◽  
A. Arola ◽  
K. Korhonen ◽  
H. Lihavainen ◽  
...  
Keyword(s):  
Technical Note ◽  
New Delhi ◽  
Aerosol Layer ◽  
Raman Lidar ◽  
Extinction Coefficients ◽  
Seasonal Characteristics ◽  
Lidar Measurements ◽  
Multi Wavelength ◽  
Lidar Ratio ◽  
One Year

Abstract. One year of multi-wavelength (3 backscatter + 2 extinction + 1 depolarization) Raman lidar measurements at Gual Pahari, close to New Delhi, were analysed. The data was split into four seasons: spring (March–May), summer (June–August), autumn (September–November) and winter (December–February). The vertical profiles of backscatter, extinction, and lidar ratio and their variability during each season are presented. The measurements revealed that, on average, the aerosol layer was at its highest in spring (5.5 km). In summer, the vertically averaged (between 1–3 km) backscatter and extinction coefficients had the highest averages (3.3 Mm−1 sr−1 and 142 Mm−1 at 532 nm, respectively). Aerosol concentrations were slightly higher in summer compared to other seasons, and particles were larger in size. The autumn showed the highest lidar ratio and high extinction-related Ångström exponents (AEext), indicating the presence of smaller probably absorbing particles. The winter had the lowest backscatter and extinction coefficients, but AEext was the highest, suggesting still a large amount of small particles.

scholarly journals Latitudinal characteristics of GPS derived ionospheric TEC: a comparative study with IRI 2012 model

2014 ◽  
Vol 57 (5) ◽  
Author(s):  
Monti Chakraborty ◽  
Sanjay Kumar ◽  
Barin Kumar De ◽  
Anirban Guha
Keyword(s):  
Electron Density ◽  
Seasonal Variations ◽  
Activity Period ◽  
High Solar Activity ◽  
Electron Content ◽  
Low Latitude ◽  
Total Electron ◽  
Gps Satellites ◽  
Characteristics Analysis ◽  
One Year

<p>The present study investigates the variation of Total Electron Content (TEC) using Global Positioning System (GPS) satellites from four equatorial to mid-latitudes stations over a period of one year. The stations are Port Blair (11.63°N, 92.70°E), Agartala (23.75°N, 91.25°E), Lhasa (29.65°N, 91.10°E) and Urumqi (43.46°N, 87.16°E). The diurnal, monthly and seasonal variations of TEC have been explored to study its latitudinal characteristics. Analysis of TEC data from these stations reveals the characteristics of latitudinal variation of Equatorial Ionospheric Anomaly (EIA). To validate the latest IRI 2012 model, the monthly and seasonal variations of GPS-TEC at all the four stations have been compared with the model for three different topside options of electron density, namely, NeQuick, IRI-01-corr and IRI-2001. TEC predictions from IRI-2001 top side electron density option using IRI 2012 model overestimates the observed TEC especially at the low latitudes. TEC from IRI- NeQuick and IRI-01-corr options shows a tendency to underestimate the observed TEC during the day time particularly in low latitude region in the high solar activity period. The agreement between the model and observed values are reasonable in mid latitude regions. However, a discrepancy between IRI 2012 derived TEC with the ground based observations at low latitude regions is found. The discrepancy appears to be higher in low-latitude regions in comparison to mid latitude regions. It is concluded that largest discrepancy in TEC occur as a result of poor estimation of the hmF2 and foF2 from the coefficients.</p>

One year of water vapour Raman Lidar measurements at the Andalusian Centre for Environmental Studies (CEAMA)

2008 ◽  
Vol 29 (17-18) ◽  
pp. 5437-5453 ◽  
Author(s):  
J. L. Guerrero‐Rascado ◽  
B. Ruiz ◽  
G. Chourdakis ◽  
G. Georgoussis ◽  
L. Alados‐Arboledas
Keyword(s):  
Water Vapour ◽  
Environmental Studies ◽  
Raman Lidar ◽  
Lidar Measurements ◽  
One Year
Sign in / Sign up

Export Citation Format

Share Document