Preliminary results of water cloud and aerosol properties in the Yinchuan area using a Multi-wavelength lidar based on dual field of view

2022 ◽  
Vol 148 ◽  
pp. 107784
Author(s):  
Jiandong Mao ◽  
Xiangyu Dong ◽  
Hu Zhao ◽  
Chunyan Zhou ◽  
Xin Gong ◽  
...  
Keyword(s):  
Field Of View ◽  
Preliminary Results ◽  
Multi Wavelength ◽  
Water Cloud ◽  
Aerosol Properties

The outbursts of comet 29P/SW-1 and C/2020 R4 (ATLAS)

2021 ◽  
Author(s):  
Zhong-Yi Lin ◽  
Michael S. P. Kelly ◽  
Huen-Wing Ip
Keyword(s):  
Gas Production ◽  
Active Period ◽  
Production Rates ◽  
Preliminary Results ◽  
Long Period ◽  
Level Of Activity ◽  
Multi Wavelength ◽  
Dust Coma ◽  
Period Comet

<p>We present an analysis of the dynamic dust coma of Centaur 29P/Schewassmann-Wachmann 1 and long-period comet C/2020 R4 (Atlas). Comet P/SW1 has exhibited a considerable level of activity (so-called outbursts) since its discovery in 1925. In 2011, we found the morphology of comet P/SW 1 showed dust features in the form of jets, spirals and shells. This year, we have obtained multi-wavelength observations of 29P/SW 1's dust coma at Lulin observatory and we will present preliminary results including the morphological analysis and the colour (B-V, V-R, and R-I) investigation of the dust coma when comet is at quiet and active period.</p> <p>At least three outbursts found within two weeks from comet Atlas is unusual for long-period comet. However, we didn’t find any new jet features and fragments from the morphology of comet Atlas. Except for the color investigation during the outburst, we will also give the dust/gas production rates in the comparison between pre- and post-outbursts.</p>

scholarly journals A Multi-Wavelength Study of X-ray Selected AGN

1989 ◽  
Vol 134 ◽  
pp. 199-200
Author(s):  
R. J. V. Brissenden ◽  
I. R. Tuohy ◽  
G. V. Bicknell ◽  
R. A. Remillard ◽  
D. A. Schwartz
Keyword(s):  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
High Energy ◽  
Astronomy Observatory ◽  
X Ray ◽  
Preliminary Results ◽  
Multi Wavelength ◽  
Uv Excess ◽  
Modulation Collimator

A sample of Active Galactic Nuclei (AGN) have been discovered during a program to identify the optical counterparts of X-ray sources detected by the Modulation Collimator experiment of the High Energy Astronomy Observatory-1 (HEAO-1). UV-excess techniques were used to identify the X-ray sources (Remillard et al. 1986) and the details of the identifications are given elsewhere (Remillard et al. 1988, Brissenden et al. 1988). We report here the preliminary results of a multi-wavelength study of these new AGN.

scholarly journals Size distribution of near-surface aerosols and its relation to the columnar aerosol optical depths

2004 ◽  
Vol 22 (10) ◽  
pp. 3347-3351 ◽  
Author(s):  
P. S. Pillai ◽  
K. Krishna Moorthy
Keyword(s):  
Size Distribution ◽  
Quartz Crystal Microbalance ◽  
Relative Abundance ◽  
Mass Concentration ◽  
Quartz Crystal ◽  
Near Surface ◽  
Aerosol Mass ◽  
Aerosol Mass Concentration ◽  
Multi Wavelength ◽  
Aerosol Properties

Abstract. Simultaneous data on Aerosol Optical Depth (AOD) and size segregated, near-surface, aerosol mass concentration was obtained from a Multi wavelength Solar Radiometer (MWR) and Quartz Crystal Microbalance Impactor (QCM), respectively. These were used to examine the association between near-surface aerosol properties and columnar AOD. The spectral AODs were approximated to the Ångström relation τp=βλ-α, and the wavelength exponent α and turbidity coefficient β have been obtained. In general, α was found to be well associated with the relative abundance of accumulation mode aerosols (estimated from the simultaneous QCM data) while β followed the variations of the coarse mode aerosol mass concentration; the association being closer during periods of continental airmass.

scholarly journals The Nature of High HI Mass-to-Light Ratio Galaxies

2004 ◽  
Vol 217 ◽  
pp. 48-49
Author(s):  
Bradley E. Warren ◽  
Helmut Jerjen ◽  
Bärbel S. Koribalski
Keyword(s):  
Dwarf Galaxies ◽  
Bright Galaxy ◽  
Preliminary Results ◽  
Multi Wavelength

We present here preliminary results of our multi-wavelength investigation into high HI mass-to-light ratio dwarf galaxies identified in the HIPASS Bright Galaxy Catalog.

scholarly journals Ceilometer aerosol profiling versus Raman lidar in the frame of the INTERACT campaign of ACTRIS

2015 ◽  
Vol 8 (5) ◽  
pp. 2207-2223 ◽  
Author(s):  
F. Madonna ◽  
F. Amato ◽  
J. Vande Hey ◽  
G. Pappalardo
Keyword(s):  
Atmospheric Aerosols ◽  
Signal To Noise Ratio ◽  
Cloud Base ◽  
Raman Lidar ◽  
Backscatter Coefficient ◽  
Lidar Measurements ◽  
Multi Wavelength ◽  
Strong Motivation ◽  
Technological Improvements ◽  
Aerosol Properties

Abstract. Despite their differences from more advanced and more powerful lidars, the low construction and operation cost of ceilometers (originally designed for cloud base height monitoring) has fostered their use for the quantitative study of aerosol properties. The large number of ceilometers available worldwide represents a strong motivation to investigate both the extent to which they can be used to fill in the geographical gaps between advanced lidar stations and also how their continuous data flow can be linked to existing networks of the more advanced lidars, like EARLINET (European Aerosol Research Lidar Network). In this paper, multi-wavelength Raman lidar measurements are used to investigate the capability of ceilometers to provide reliable information about atmospheric aerosol properties through the INTERACT (INTERcomparison of Aerosol and Cloud Tracking) campaign carried out at the CNR-IMAA Atmospheric Observatory (760 m a.s.l., 40.60° N, 15.72° E), in the framework of the ACTRIS (Aerosol Clouds Trace gases Research InfraStructure) FP7 project. This work is the first time that three different commercial ceilometers with an advanced Raman lidar are compared over a period of 6 months. The comparison of the attenuated backscatter coefficient profiles from a multi-wavelength Raman lidar and three ceilometers (CHM15k, CS135s, CT25K) reveals differences due to the expected discrepancy in the signal to noise ratio (SNR) but also due to changes in the ambient temperature on the short and mid-term stability of ceilometer calibration. Therefore, technological improvements are needed to move ceilometers towards operational use in the monitoring of atmospheric aerosols in the low and free troposphere.

scholarly journals Enhancement of aerosol characterization using synergy of lidar and sun – photometer coincident observations: the GARRLiC algorithm

2013 ◽  
Vol 6 (2) ◽  
pp. 2253-2325 ◽  
Author(s):  
A. Lopatin ◽  
O. Dubovik ◽  
A. Chaikovsky ◽  
Ph. Goloub ◽  
T. Lapyonok ◽  
...  
Keyword(s):  
Refractive Index ◽  
Size Distribution ◽  
Complex Refractive Index ◽  
Single Scattering ◽  
Inversion Algorithm ◽  
Multi Wavelength ◽  
Lidar Observations ◽  
Aerosol Properties ◽  
Different Altitudes ◽  
Aerosol Type

Abstract. Currently most of experiments pursuing comprehensive characterization of atmosphere include coordinated observations by both lidar and radiometers in order to obtain important complimentary information about aerosol properties. The passive observations by radiometers from ground are mostly sensitive to the properties of aerosol in total atmospheric column and have very limited sensitivity to vertical structure of the atmosphere. Such observations are commonly used for measuring aerosol optical thickness and deriving the information about aerosol microphysics including aerosol particles shape, size distribution, and complex refractive index. In a contrast, lidar observations of atmospheric responses from different altitudes to laser pulses emitted from ground are designed to provide accurate profiling of the atmospheric properties. The interpretation of the lidar observation generally relies on some assumptions about aerosol type and loading. Here we present the GARRLiC algorithm (Generalized Aerosol Retrieval from Radiometer and Lidar Combined data) that simultaneously inverts co-incident lidar and radiometer observations and derives a united set of aerosol parameters. Such synergetic retrieval is expected to result in additional enhancements in derived aerosol properties because the backscattering observations by lidar add some sensitivity to the columnar properties of aerosol, while radiometric observations provide sufficient constraints on aerosol type and loading that generally are missing in lidar signals. GARRLiC is based on AERONET algorithm for inverting combined observations by radiometer and multi-wavelength elastic lidar observations. It is expected that spectral changes of backscattering signal obtained by multi-wavelength lidar at different altitudes provide some sensitivity to the vertical variability of aerosol particle sizes. In order to benefit from this sensitivity the algorithm is set to derive not only the vertical profile of total aerosol concentration but it also differentiates between the contributions of fine and coarse modes of aerosol. The detailed microphysical properties are assumed height independent and different for each mode and expected to be derived as a part of the retrieval. Thus, the GARRLiC inversion algorithm retrieves vertical distribution of both fine and coarse aerosol concentrations as well as the size distribution, complex refractive index and single scattering albedo for each mode. The potential and limitations of the method are demonstrated by the series of sensitivity tests. The practical outcome of the approach is illustrated by applications of the algorithm to the real lidar and radiometer observations obtained over selected AERONET site.

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