Laser heterodyne radiometers (LHR) for in situ ground-based remote sensing of greenhouse gases in the atmospheric column

2020 ◽  
Author(s):  
Jingjing Wang ◽  
Fengjiao Shen ◽  
Tu Tan ◽  
Zhensong Cao ◽  
Xiaoming Gao ◽  
...  
Keyword(s):  
Solar Radiation ◽  
Greenhouse Gases ◽  
Global Climate ◽  
Tunable Laser ◽  
Local Oscillator ◽  
Laser Source ◽  
Atmospheric Column ◽  
Remote Measurements ◽  
Laser Heterodyne ◽  
Regional Air Quality

<p>Measurements of vertical concentration profiles of greenhouse gases (GHGs) is extremely important for our understanding of regional air quality and global climate change trends. In this context, laser heterodyne radiometer (LHR) technique has been developed <sup>[1-5]</sup> for ground-based remote measurements of GHGs in the atmospheric column.</p><p>Solar radiation undergoing absorption by multi-species in the atmosphere is coupled into a LHR instrument where the sunlight is mixed with a local oscillator (LO), being usually a tunable laser source, in a fast photodetector. Beating note at radio frequency (RF) resulted from this photomixing contains absorption information of the LO-targeted molecules. Scanning the LO frequency across the target molecular absorption lines allows one to extract the corresponding absorption features from the total absorption of the solar radiation by all molecules in the atmospheric column. Near-IR (~1.5 µm) and mid-IR (~8 µm) <sup>[6]</sup> LHRs have been recently developed in the present work. Field campaigns have been performed on the roof of the platform of IRENE in Dunkerque (51.05°N/2.34°E).</p><p>The developed LHR instruments as well as the preliminary results of their applications to the measurements of CH<sub>4</sub>, N<sub>2</sub>O, CO<sub>2</sub> (including <sup>13</sup>CO<sub>2</sub>/<sup>12</sup>CO<sub>2</sub>), H<sub>2</sub>O vapor (and its isotopologue HDO) in the atmospheric column will be presented and discussed.</p><p><strong>Acknowledgments</strong> The authors thank the financial supports from the LABEX CaPPA project (ANR-10-LABX005), the MABCaM (ANR-16-CE04-0009) and the MULTIPAS (ANR-16-CE04-0012) contracts, as well as the CPER CLIMIBIO program. S. F. thanks the program Labex CaPPA and the "Pôle Métropolitain de la Côte d’Opale" (PMCO) for the PhD fellowship support.</p><p><strong>References </strong></p><p>[1] R. T. Menzies, and R. K. Seals, Science <strong>197</strong> (1977) 1275-1277</p><p>[2] D. Weidmann, T. Tsai, N. A. Macleod, and G. Wysocki, Opt. Lett. <strong>36</strong> (2011) 1951-1953</p><p>[3] E. L. Wilson, M. L. McLinden, and J. H. Miller, Appl. Phys. B <strong>114</strong> (2014) 385-393</p><p>[4] A. Rodin, A. Klimchuk, A. Nadezhdinskiy, D. Churbanov, and M. Spiridonov, Opt. Express <strong>22</strong> (2014) 13825-13834</p><p>[5] J. Wang, G. Wang, T. Tan, G. Zhu, C. Sun, Z. CAO, W. Chen, and X. Gao, Opt. Express <strong>27</strong> (2019) 9600-9619</p><p>[6] F. Shen, P. Jeseck, Y. Te, T. Tan, X. Gao, E. Fertein, and W. Chen, Geophys. Res. Abstracts, <strong>20 </strong>(2018) EGU2018-79</p>

A portable dual-channel laser heterodyne radiometer for simultaneous remote measurements of CH4 and CO2 in the atmospheric column

2021 ◽  
Author(s):  
Jingjing Wang ◽  
Tu Tan ◽  
Zhengyue Xue ◽  
Xiaoming Gao ◽  
Weidong Chen
Keyword(s):  
Greenhouse Gases ◽  
Signal To Noise Ratio ◽  
Qinghai Province ◽  
Atmospheric Column ◽  
Data Inversion ◽  
Dual Channel ◽  
Custom Made ◽  
Remote Measurements ◽  
Laser Heterodyne ◽  
Heterodyne Radiometer

<p>Laser heterodyne spectroscopic measurement technique<sup>[1]</sup> has been proved to be a powerful and effective remote sensing tool for measurements of greenhouse gases in the atmospheric column<sup>[2-6]</sup>. In the present work, we report the development of a portable all-fiber coupled dual-channel laser heterodyne radiometer (LHR) and its field deployment. Two DFB lasers operating at 1650.9 nm and 1603.6 nm are used for the remote measurements of column CH<sub>4</sub> and CO<sub>2</sub>, respectively. A fiber optic switch is used to modulate and split the collected sunlight into two channels for simultaneous measurements of both target greenhouse gases. Custom-made preamplifiers combined with digital lock-in amplifiers are used to extract the laser heterodyne signals. The spectral resolution of the instrument is about 0.00442 cm<sup>-1</sup>, and the signal-to-noise ratio of the measured spectrum of about 250 is achieved with 0.8 s average time per sampling datum. The developed LHR instrument was successfully deployed to a field atmospheric observation experiment (in Dachaidan district, Qinghai province, China).</p><p>The experimental detail including the LHR instrument integration, dual-channel measurement results of column CH<sub>4</sub> and CO<sub>2</sub> and preliminary data inversion results will be presented and discussed.</p><p><strong>Acknowledgments. </strong>The project was supported by the national key R&D program of China (2017YFC0209705). The authors thank the financial supports from the CPER CLIMIBIO program, the Labex CaPPA project (ANR-10-LABX005).</p><p><strong>References</strong></p><p>[1] D. Weidmann, T. Tsai, N. A. Macleod, G. Wysocki, Opt. Lett. <strong>36 </strong>(2011) 1951-1953.</p><p>[2] E. L. Wilson, A. J. DiGregorio, G. Villanueva, C. E. Grunberg, et al., Appl. Phys. B <strong>125 </strong>(2019) 211-219.</p><p>[3] D. S. Bomse, J. E. Tso, M. M. Flors, J. H. Miller, Appl. Opt. <strong>59 </strong>(2020) B10-B17.</p><p>[4] J. Wang, G. Wang, T. Tan, G. Zhu, C. Sun, Z. Cao, W. Chen, X. Gao, Opt. Express <strong>27</strong> (2019) 9610-9619</p><p>[5] A. Rodin, A. Klimchuk, A. Nadezhdinskiy, D. Churbanov, et al., Opt. Express <strong>22 </strong>(2014) 13825-13834.</p><p>[6] E. L. Wilson, M. L. McLinden, J. H. Miller, H. R. Melroy, et al., Appl. Phys. B <strong>114 </strong>(2014) 385-393.</p>

scholarly journals Climate Dynamics of the Spatiotemporal Changes of Vegetation NDVI in Northern China from 1982 to 2015

2021 ◽  
Vol 13 (2) ◽  
pp. 187
Author(s):  
Rui Sun ◽  
Shaohui Chen ◽  
Hongbo Su
Keyword(s):  
Solar Radiation ◽  
Vegetation Index ◽  
Global Climate ◽  
Regional Scale ◽  
Northern China ◽  
Climate Dynamics ◽  
High Coverage ◽  
Vegetation Growth ◽  
Temperature And Precipitation ◽  
Precipitation And Temperature

As an important part of a terrestrial ecosystem, vegetation plays an important role in the global carbon-water cycle and energy flow. Based on the Global Inventory Monitoring and Modeling System (GIMMS) third generation of Normalized Difference Vegetation Index (NDVI3g), meteorological station data, climate reanalysis data, and land cover data, this study analyzed the climate dynamics of the spatiotemporal variations of vegetation NDVI in northern China from 1982 to 2015. The results showed that growth season NDVI (NDVIgs) increased significantly at 0.006/10a (p < 0.01) in 1982–2015 on the regional scale. The period from 1982 to 2015 was divided into three periods: the NDVIgs increased by 0.026/10a (p < 0.01) in 1982–1990, decreased by −0.002/10a (p > 0.1) in 1990–2006, and then increased by 0.021/10a (p < 0.01) during 2006–2015. On the pixel scale, the increases in NDVIgs during 1982–2015, 1982–1990, 1990–2006, and 2006–2015 accounted for 74.64%, 85.34%, 48.14%, and 68.78% of the total area, respectively. In general, the dominant climate drivers of vegetation growth had gradually switched from solar radiation, temperature, and precipitation (1982–1990) to precipitation and temperature (1990–2015). For woodland, high coverage grassland, medium coverage grassland, low coverage grassland, the dominant climate drivers had changed from temperature and solar radiation, solar radiation and precipitation, precipitation and solar radiation, solar radiation to precipitation and solar radiation, precipitation, precipitation and temperature, temperature and precipitation. The areas controlled by precipitation increased significantly, mainly distributed in arid, sub-arid, and sub-humid areas. The dominant climate drivers for vegetation growth in the plateau climate zone or high-altitude area changed from solar radiation to temperature and precipitation, and then to temperature, while in cold temperate zone, changed from temperature to solar radiation. These results are helpful to understand the climate dynamics of vegetation growth, and have important guiding significance for vegetation protection and restoration in the context of global climate change.

scholarly journals Uncertainties in emissions estimates of greenhouse gases and air pollutants in India and their impacts on regional air quality

2017 ◽  
Vol 12 (6) ◽  
pp. 065002 ◽  
Author(s):  
Eri Saikawa ◽  
Marcus Trail ◽  
Min Zhong ◽  
Qianru Wu ◽  
Cindy L Young ◽  
...  
Keyword(s):  
Air Quality ◽  
Greenhouse Gases ◽  
Air Pollutants ◽  
Regional Air Quality

SENSITIVITY MEASUREMENT OF FIBRE BRAGG GRATING SENSOR

2016 ◽  
Vol 78 (3) ◽  
Author(s):  
Suzairi Daud ◽  
Muhammad Safwan Abd Aziz ◽  
Kashif Tufail Chaudhary ◽  
Mahdi Bahadoran ◽  
Jalil Ali
Keyword(s):  
Tunable Laser ◽  
Sensor System ◽  
Laser Source ◽  
Bragg Grating ◽  
Wavelength Shift ◽  
Fibre Bragg Grating ◽  
Sensor Head ◽  
Fibre Bragg Grating Sensor ◽  
Pass Through ◽  
Bragg Grating Sensor

A practical pass-through type fibre Bragg grating (FBG) temperature sensor system have been designed, developed, simulated, and experimentally investigated. The performance of FBG was evaluated in harsh environments exposed under direct sunlight, rain, and wind. The sensor system designed directly focused with convex and hand lens. The temperature of FBG’s sensor head been measured. The broadband laser source was launched into the system using tunable laser source (TLS) and both transmission and reflection spectra of FBG sensor were measured by optical spectrum analyzer (OSA). Results shows that the Bragg wavelength shift,  increased proportionally with the temperature changes. The sensitivity of FBG were recorded at 0.0100 and 0.0132 nm °C-1 for the systems where convex and hand lens applied to the FBG’s sensor head respectively, while the sensitivity of 0.0118 nm °C-1 measured for the system without any focusing element applied.

scholarly journals Mediterranean Precipitation Response to Greenhouse Gases and Aerosols

2018 ◽  
Author(s):  
Tao Tang ◽  
Drew Shindell ◽  
Bjørn H. Samset ◽  
Oliviér Boucher ◽  
Piers M. Forster ◽  
...  
Keyword(s):  
Greenhouse Gases ◽  
Climate Models ◽  
Hydrological Cycle ◽  
Global Climate ◽  
Local Heating ◽  
Global Climate Models ◽  
Historical Period ◽  
Radiative Balance ◽  
Precipitation Decrease ◽  
The Mediterranean

Abstract. Atmospheric aerosols and greenhouse gases affect cloud properties, radiative balance and thus, the hydrological cycle. Observations show that precipitation has decreased in the Mediterranean since the 20th century, and many studies have investigated possible mechanisms. So far, however, the effects of aerosol forcing on Mediterranean precipitation remain largely unknown. Here we compare Mediterranean precipitation responses to individual forcing agents in a set of state-of-the-art global climate models (GCMs). Our analyses show that both greenhouse gases and aerosols can cause drying in the Mediterranean, and that precipitation is more sensitive to black carbon (BC) forcing than to well-mixed greenhouse gases (WMGHGs) or sulfate aerosol. In addition to local heating, BC appears to reduce precipitation by causing an enhanced positive North Atlantic Oscillation (NAO)/Arctic Oscillation (AO)-like sea level pressure (SLP) pattern, characterized by higher SLP at mid-latitudes and lower SLP at high-latitudes. WMGHGs cause a similar SLP change, and both are associated with a northward diversion of the jet stream and storm tracks, reducing precipitation in the Mediterranean while increasing precipitation in Northern Europe. Though the applied forcings were much larger, if forcings are scaled to those of the historical period of 1901–2010, roughly one-third (31 ± 17 %) of the precipitation decrease would be attributable to global BC forcing with the remainder largely attributable to WMGHGs whereas global scattering sulfate aerosols have negligible impacts. The results from this study suggest that future BC emissions may significantly affect regional water resources, agricultural practices, ecosystems, and the economy in the Mediterranean region.

scholarly journals Halogenated Greenhouse Gases Made Global Warming Primarily

2022 ◽  
Author(s):  
Qing-Bin Lu
Keyword(s):  
Sea Ice ◽  
Greenhouse Gases ◽  
Land Surface ◽  
Southern Oscillation ◽  
Theoretical Calculations ◽  
Global Climate ◽  
Surface Air Temperature ◽  
The Arctic ◽  
Sea Ice Extent ◽  
Snow Cover Extent

Abstract Time-series observations of global lower stratospheric temperature (GLST), global land surface air temperature (LSAT), global mean surface temperature (GMST), sea ice extent (SIE) and snow cover extent (SCE), together with observations reported in Paper I, combined with theoretical calculations of GLSTs and GMSTs, have provided strong evidence that ozone depletion and global climate changes are dominantly caused by human-made halogen-containing ozone-depleting substances (ODSs) and greenhouse gases (GHGs) respectively. Both GLST and SCE have become constant since the mid-1990s and GMST/LSAT has reached a peak since the mid-2000s, while regional continued warmings at the Arctic coasts (particularly Russia and Alaska) in winter and spring and at some areas of Antarctica are observed and can be well explained by a sea-ice-loss warming amplification mechanism. The calculated GMSTs by the parameter-free warming theory of halogenated GHGs show an excellent agreement with the observed GMSTs after the natural El Niño southern oscillation (ENSO) and volcanic effects are removed. These results provide a convincing mechanism of global climate change and will make profound changes in our understanding of atmospheric processes. This study also emphasizes the critical importance of continued international efforts in phasing out all anthropogenic halogenated ODSs and GHGs.

scholarly journals Climate Change and Aerosol Sciences

2021 ◽  
pp. 1-13
Author(s):  
Kehan Li
Keyword(s):  
Climate Change ◽  
Global Warming ◽  
Particulate Matter ◽  
Environmental Policy ◽  
Solar Radiation ◽  
Greenhouse Gases ◽  
Atmospheric Aerosols ◽  
Environmental Policies ◽  
Modern Times

Climate change is of great importance in modern times and global warming is considered as a significant part of climate change. It is proved that human’s emissions such as greenhouse gases are one of the main sources of global warming (IPCC, 2018). Apart from greenhouse gases, there is another kind of matter being released in quantity via emissions from industries and transportations and playing an important role in global warming, which is aerosol. However, atmospheric aerosols have the net effect of cooling towards global warming. In this paper, climate change with respect to global warming is briefly introduced and the role of aerosols in the atmosphere is emphasized. Besides, properties of aerosols including dynamics and thermodynamics of aerosols as well as interactions with solar radiation are concluded. In the end, environmental policies and solutions are discussed. Keywords: Climate change, Global warming, Atmospheric aerosols, Particulate matter, Radiation, Environmental policy.

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