Mobile multi-wavelength polarization Raman lidar for water vapor, cloud and aerosol measurement

Wu, Songhua; Song, Xiaoquan; Liu, Bingyi; Dai, Guangyao; Liu, Jintao; Zhang, Kailin; Qin, Shengguang; Hua, Dengxin; Gao, Fei; Liu, Liping

doi:10.1364/oe.23.033870

Cited by 31 publications

(16 citation statements)

References 47 publications

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“…The basic parameters of CL31 are listed in the left of Table 1 [17]. The lidar measurements are conducted with the fully automatic portable multi-wavelength Raman and polarization lidar WACAL [18] by Ocean University of China (OUC). Figure 2b shows the photo of WACAL, and the basic parameters are listed in the right of Table 1.…”

Section: Methodsmentioning

confidence: 99%

Lidar and Ceilometer Observations and Comparisons of Atmospheric Cloud Structure at Nagqu of Tibetan Plateau in 2014 Summer

et al. 2017

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Abstract:In the project of the Third Tibetan Plateau Experiment of Atmospheric Science (TIPEX III), the intensive observation of cloud and precipitation in Nagqu was conducted from 1 July to 31 August 2014. The CL31 ceilometer and a WAter vapor, Cloud and Aerosol Lidar (WACAL) were deployed and focused on studying the cloud macroscopic characteristics and vertical distribution. The statistical result of CL31 ceilometer in continuous operation mode shows that the cloud occurrence is about 81% with a majority of simple one-layer cloud. The cloud base and top height are retrieved by improved differential zero-crossing method using lidar data. The results of cloud base height (CBH) are compared with CL31 ceilometer, showing a good consistency with each other, however, in some cases, the CL31 ceilometer overestimates the CBH and is also validated by synchronous radiosonde data. The time snippet comparisons of cloud property between CL31 ceilometer and lidar imply that the cloud properties have obvious diurnal variations with "U" shape distribution. The cloud development including the time-spatial distribution features also has distinct diurnal variations based on the lidar measurement. The detection range of lidar goes beyond the maximum height of CL31 ceilometer, offering substantial observations to the analysis of cirrus cloud radiation characteristics and formation mechanism.

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Section: Methodsmentioning

confidence: 99%

Lidar and Ceilometer Observations and Comparisons of Atmospheric Cloud Structure at Nagqu of Tibetan Plateau in 2014 Summer

et al. 2017

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“…By this algorithm, cloud layers apparent in the return signal are identified. However, if the lower clouds were too thick to be penetrated, the higher clouds will not be detected and cannot be identified (Wu et al, 2015, Song et al, 2017. During this campaign, the cloud base heights determined by the WACAL and that from the co-located VAISALA CL31 ceilometer measurements were compared and the results were reported by Song et 5 al.…”

Section: Extraction Of the Cloud Base And Top Heightsmentioning

confidence: 97%

“…The WACAL was built up successfully in 2013 by the lidar group at Ocean University of China. The details of WACAL has been described by Wu et al in a separated paper (Wu et al, 2015). 15…”

Section: Water Vapor Cloud and Aerosol Lidar (Wacal)mentioning

confidence: 99%

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Optical and Geometrical Properties of Cirrus Clouds over the Tibetan Plateau Measured by Lidar and Radiosonde Sounding at the Summertime in 2014

Dai

Song

et al. 2017

Preprint

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Abstract. Optical and geometrical characteristics of cirrus clouds over Naqu (31.48°N,92.06°E), the Tibetan Plateau were determined from lidar and radiosonde measurements performed during the third TIbetan Plateau EXperiment of atmospheric sciences (TIPEX III) campaign from July to August 2014. For the analysis of the temperature dependence, the simultaneous observations by lidar and radiosonde were conducted. Cirrus clouds were generally observed ranging from 9.7 to 16.5 km above sea level (a.s.l.), with the cirrus middle temperatures in the range from −79.7 to −26.0 C  . The cloud thickness generally 15 differed from 0.12 to 2.55 km with a mean thickness of 1.22  0.70 km and 85.7% of the case studies had thickness smaller than 1.5 km. The retrievals of linear particle depolarization ratio, extinction coefficient and optical depth of cirrus clouds were performed. Moreover, the multiple scattering effect inside of cirrus cloud was corrected. The linear particle depolarization ratio of the cirrus clouds varied from 0.36 to 0.52, with a mean value of 0.44  0.037. The optical depth of all the cirrus clouds was between 0.01 and 3 following the scheme of Fernald-Klett method. Sub-visual, thin and opaque cirrus clouds were 20 observed at 9.52%, 57.14% and 33.34% of the measured cases, respectively. The temperature and thickness dependencies on optical properties were studied in detail. A maximum cirrus thickness of around 2 km was found at temperatures between −60 and −50 C  . This study shows that the cirrus mean extinction coefficient of the cirrus clouds increase with the increase of temperature. However, our measurements indicate that the linear particle depolarization ratio has the opposite change tendency along with temperature. The relationships between the presence of cirrus clouds and the temperature anomaly and deep 25Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2017-355 Manuscript under review for journal Atmos. Meas. Tech. Discussion started: 11 December 2017 c Author(s) 2017. CC BY 4.0 License. 2 convective activity are also discussed. The formation of cirrus clouds is also investigated and it has apparent relationship with the dynamic processes of Rossby wave and deep convective activity over the Tibetan Plateau. The cloud radiative forcing is calculated by Fu-Liou model and increases monotonously with the increase of optical depth.

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“…Lidar systems can make atmospheric observations at different wavelengths ranging from UV to NIR (such as 355 nm, 532 nm and 1064 nm) (Wu et al, 2015;McKendry et al, 2009;Xia et al, 2007). Recently, the 1.5 µm lidar has been recognized as an important instrument in the measurements of PM10 (Lisenko, Kugeiko, & Khomich, 2016), since it studies the Mie backscattering at longer wavelength than those systems mentioned above.…”

Section: Introductionmentioning

confidence: 99%

Adaptive inversion algorithm for 1.5μm visibility lidar incorporating in situ Angstrom wavelength exponent

Xiang¹,

Xia²,

Dou³

et al. 2018

Optics Communications

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As one of the most popular applications of lidar systems, the atmospheric visibility is defined to be inversely proportional to the atmospheric extinction coefficient at 0.55 µm. Since the laser at 1.5 µm shows the highest maximum permissible exposure in the wavelength ranging from 0.3 µm to 10 µm, the eye-safe 1.5 µm lidar can be deployed in urban areas. In such a case, the measured extinction coefficient at 1.5 µm should be converted to that at 0.55 µm for visibility retrieval. Although several models have been established since 1962, the accurate wavelength conversion remains a challenge. An adaptive inversion algorithm for 1.5 µm visibility lidar is proposed and demonstrated by using the in situ Angstrom wavelength exponent, which is derived from either a sun photometer or an aerosol spectrometer. The impact of the particle size distribution of atmospheric aerosols and the Rayleigh backscattering of atmospheric molecules are taken into account. In comparison, the Angstrom wavelength exponent derived from the sun photometer is 7.7% higher than that derived from the aerosol spectrometer. Then, using 1.5 µm visibility lidar, the visibility with a temporal resolution of 5 min is detected over 48 hours in Hefei (31.83 • N, 117.25 • E). The average visibility error between the new method and a visibility sensor (Vaisala, PWD52) is 5.2% with the R-square value of 0.96, while the relative error between another reference visibility lidar at 532 nm and the visibility sensor is 6.7% with the R-square value of 0.91. All results agree with each other well, demonstrating the accuracy and stability of the algorithm.

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Mobile multi-wavelength polarization Raman lidar for water vapor, cloud and aerosol measurement

Cited by 31 publications

References 47 publications

Lidar and Ceilometer Observations and Comparisons of Atmospheric Cloud Structure at Nagqu of Tibetan Plateau in 2014 Summer

Lidar and Ceilometer Observations and Comparisons of Atmospheric Cloud Structure at Nagqu of Tibetan Plateau in 2014 Summer

Optical and Geometrical Properties of Cirrus Clouds over the Tibetan Plateau Measured by Lidar and Radiosonde Sounding at the Summertime in 2014

Adaptive inversion algorithm for 1.5μm visibility lidar incorporating in situ Angstrom wavelength exponent

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