scholarly journals Mars Methane Sources in Northwestern Gale Crater Inferred from Back-Trajectory Modeling

2021 ◽  
Author(s):  
Yangcheng Luo ◽  
Michael Mischna ◽  
John Lin ◽  
Benjamin Fasoli ◽  
Xiang Cai ◽  
...  
Keyword(s):  
Tunable Laser ◽  
Emission Region ◽  
Back Trajectory ◽  
Crater Floor ◽  
Laser Spectrometer ◽  
Gale Crater ◽  
Surface Emission ◽  
The North ◽  
Lagrangian Modeling ◽  
Modeling Techniques

Abstract During its five years of operation, the Sample Analysis at Mars (SAM) Tunable Laser Spectrometer (TLS) on board the Curiosity rover has detected six methane spikes above a low background abundance in Gale crater. The methane spikes are likely the consequence of nearby surface emission. Here we use inverse Lagrangian modeling techniques to identify probable upstream emission regions for these methane spikes at an unprecedented spatial resolution. Inside Gale crater, the northwestern crater floor casts the strongest influence on the detections. Outside Gale crater, the emission region with the strongest influence extends towards the north. The contrasting results from two consecutive methane measurements point to an active emission region to the west and the southwest of the Curiosity rover on the northwestern crater floor. The observed spike magnitude and frequency also favor emission sites on the northwestern crater floor, unless fast methane removal mechanisms that are unknown to date are at work.

scholarly journals Potential Source Areas for Atmospheric Lead Reaching Ny-Ålesund from 2010 to 2018

Atmosphere ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 388
Author(s):  
Andrea Bazzano ◽  
Stefano Bertinetti ◽  
Francisco Ardini ◽  
David Cappelletti ◽  
Marco Grotti
Keyword(s):  
North American ◽  
Enrichment Factors ◽  
Atmospheric Particulate Matter ◽  
Back Trajectory ◽  
Pb Isotope ◽  
Back Trajectories ◽  
Source Areas ◽  
The North ◽  
Central Asian ◽  
Pb Concentration

Lead content, enrichment factors, and isotopic composition (208Pb/206Pb and 207Pb/206Pb) measured in atmospheric particulate matter (PM10) samples collected for nine years at Ny-Ålesund (Svalbard islands, Norwegian Arctic) during spring and summer are presented and discussed. The possible source areas (PSA) for particulate inferred from Pb isotope ratio values were compared to cluster analysis of back-trajectories. Results show that anthropogenic Pb dominates over natural crustal Pb, with a recurring higher influence in spring, compared to summer. Crustal Pb accounted for 5–16% of the measured Pb concentration. Anthropogenic Pb was affected by (i) a Central Asian PSA with Pb isotope signature compatible with ores smelted in the Rudny Altai region, at the Russian and Kazakhstan border, which accounted for 85% of the anthropogenic Pb concentration, and (ii) a weaker North American PSA, contributing for the remaining 15%. Central Asian PSA exerted an influence on 71–86% of spring samples, without any significant interannual variation. On the contrary, 59–87% of summer samples were influenced by the North American PSA, with higher contributions during 2015 and 2018. Back-trajectory analysis agreed on the seasonal difference in PSA and highlighted a possible increased influence for North American air masses during summer 2010 and 2018, but not for summer 2015.

scholarly journals Modeling the transport of radioactive pollution in the Ussuri Gulf during the first days after the nuclear accident in the Chazhma Bay in August 1985

2020 ◽  
Author(s):  
П.А. ФАЙМАН ◽  
М.В. БУДЯНСКИЙ ◽  
М.Ю. УЛЕЙСКИЙ ◽  
С.В. ПРАНЦ ◽  
В.Л. ВЫСОЦКИЙ ◽  
...  
Keyword(s):  
Numerical Model ◽  
Coherent Structures ◽  
Empirical Data ◽  
Radioactive Fallout ◽  
Sea Surface ◽  
Radioactive Pollution ◽  
Nuclear Submarine ◽  
The North ◽  
Lagrangian Modeling ◽  
Hyperbolic Points

Представлены результаты лагранжевого моделирования распространения радиоактивного загрязнения в Уссурийском заливе на различных горизонтах по глубине на основе численной региональной модели циркуляции ROMS с использованием эмпирических данных выпадения радиоактивных осадков из атмосферы на поверхность акватории в день аварии на атомной подводной лодке в бухте Чажма 10 августа 1985 г. Показано, что радиоактивное пятно могло оставаться в Уссурийском заливе в течение первых четырех суток после аварии. Установлено, что эволюция и деформация начального пятна загрязнения на разных горизонтах обусловлены влиянием вихрей разных полярностей и размеров (мезомасштабный циклон в центре залива, субмезомасштабный антициклон на севере и мезомасштабный антициклон на юге) и лагранжевых когерентных структур, связанных с гиперболическими точками в заливе. The results of Lagrangian modeling of the transport of radioactive pollution in the Ussuri Gulf at various depths based on a regional ROMS numerical model of circulation using the empirical data on the radioactive fallout from the atmosphere at the sea surface on the day of the accident at a nuclear submarine in the Chazhma Bay in August 10, 1985. It was shown that the radioactive particles remain in the Ussuri Gulf for the first 4 days after the accident. It has been shown that the evolution and deformation of the initial pollution patch on various horizons was influenced by vortices of different polarity and size in the Ussuri Gulf (a mesoscale cyclone in the center of the Gulf, a sub-mesoscale anticyclone in the north and a mesoscale anticyclone in the south) and by Lagrangian coherent structures connected with hyperbolic points in the Gulf.

scholarly journals Airborne microplastic particles detected in the remote marine atmosphere

2020 ◽  
Vol 1 (1) ◽  
Author(s):  
Miri Trainic ◽  
J. Michel Flores ◽  
Iddo Pinkas ◽  
Maria Luiza Pedrotti ◽  
Fabien Lombard ◽  
...  
Keyword(s):  
North Atlantic ◽  
Trajectory Analysis ◽  
North Atlantic Ocean ◽  
Anthropogenic Pollution ◽  
Terminal Velocity ◽  
Back Trajectory ◽  
Marine Atmosphere ◽  
Local Production ◽  
The North ◽  
Back Trajectory Analysis

AbstractAnthropogenic pollution from marine microplastic particles is a growing concern, both as a source of toxic compounds, and because they can transport pathogens and other pollutants. Airborne microplastic particles were previously observed over terrestrial and coastal locations, but not in the remote ocean. Here, we collected ambient aerosol samples in the North Atlantic Ocean, including the remote marine atmosphere, during the Tara Pacific expedition in May-June 2016, and chemically characterized them using micro-Raman spectroscopy. We detected a range of airborne microplastics, including polystyrene, polyethylene, polypropylene, and poly-silicone compounds. Polyethylene and polypropylene were also found in seawater, suggesting local production of airborne microplastic particles. Terminal velocity estimations and back trajectory analysis support this conclusion. For technical reasons, only particles larger than 5 µm, at the upper end of a typical marine atmospheric size distribution, were analyzed, suggesting that our analyses underestimate the presence of airborne microplastic particles in the remote marine atmosphere.

scholarly journals Long-Term Observation of Atmospheric Speciated Mercury during 2007–2018 at Cape Hedo, Okinawa, Japan

Atmosphere ◽  
2019 ◽  
Vol 10 (7) ◽  
pp. 362 ◽  
Author(s):  
Kohji Marumoto ◽  
Noriyuki Suzuki ◽  
Yasuyuki Shibata ◽  
Akinori Takeuchi ◽  
Akinori Takami ◽  
...  
Keyword(s):  
Elemental Mercury ◽  
Cold Season ◽  
Global Scale ◽  
Back Trajectory ◽  
Asian Continent ◽  
Okinawa Island ◽  
Gaseous Elemental Mercury ◽  
The North ◽  
Back Trajectory Analysis ◽  
North Edge

The concentrations of atmospheric gaseous elemental mercury (GEM), gaseous oxidized mercury (GOM), and particle-bound mercury (particles with diameter smaller than 2.5 μm; PBM2.5) were continuously observed for a period of over 10 years at Cape Hedo, located on the north edge of Okinawa Island on the border of the East China Sea and the Pacific Ocean. Regional or global scale mercury (Hg) pollution affects their concentrations because no local stationary emission sources of Hg exist near the observation site. Their concentrations were lower than those at urban and suburban cities, as well as remote sites in East Asia, but were slightly higher than the background concentrations in the Northern Hemisphere. The GEM concentrations exhibited no diurnal variations and only weak seasonal variations, whereby concentrations were lower in the summer (June–August). An annual decreasing trend for GEM concentrations was observed between 2008 and 2018 at a rate of −0.0382 ± 0.0065 ng m−3 year−1 (−2.1% ± 0.36% year−1) that was the same as those in Europe and North America. Seasonal trend analysis based on daily median data at Cape Hedo showed significantly decreasing trends for all months. However, weaker decreasing trends were observed during the cold season from January to May, when air masses are easily transported from the Asian continent by westerlies and northwestern monsoons. Some GEM, GOM, and PBM2.5 pollution events were observed more frequently during the cold season. Back trajectory analysis showed that almost all these events occurred due to the substances transported from the Asian continent. These facts suggested that the decreasing trend observed at Cape Hedo was influenced by the global decreasing GEM trend, but the rates during the cold season were restrained by regional Asian outflows. On the other hand, GOM concentrations were moderately controlled by photochemical production in summer. Moreover, both GOM and PBM2.5 concentrations largely varied during the cold season due to the influence of regional transport rather than the trend of atmospheric Hg on a global scale.

CO2 and CH4 observations surrounding Beijing to to distinguish possible emission processes and locations

2020 ◽  
Author(s):  
J. William Munger ◽  
Shuxiao Wang ◽  
Chris Nielsen ◽  
Michael B. McElroy
Keyword(s):  
Rapid Development ◽  
District Heating ◽  
Air Pollutant ◽  
Back Trajectory ◽  
Multiple Sources ◽  
Urban Centers ◽  
Mixing Ratios ◽  
The North ◽  
Back Trajectory Analysis ◽  
Starting Point

<p>CO<sub>2</sub> and CH<sub>4</sub> are radiatively important trace gases closely associated with human activity particularly in urban emission hotspots. Through rapid development and economic growth China has become a major source of CO<sub>2</sub>. CO<sub>2</sub> emission inventories for China are becoming increasingly accurate. CH<sub>4</sub> emissions in China are not as well characterized, though for various reasons, including; Chinese policies mandating conversion from coal to natural gas for district heating, intensification of agriculture, and the large volumes of urban waste that must be managed, it is likely CH<sub>4</sub> emissions from Chinese urban centers could be significant. As part of an ongoing Tsinghua – Harvard collaboration we have set up a pair of atmospheric observatories to the north and south of Beijing. The northern site (Miyun) is 75km NNE and the southern site, Dashiwo, is 63 km SSW of the center of Beijing. Miyun has been in semi continuous operation since 2005. Miyun was located to sample Beijing urban outflow as well as clean airmasses depending on wind direction. Dashiwo is located primarily to capture the polluted air coming into Beijing from Hebei province, though it will also be influenced at times by cleaner airmasses coming over the mountains on the western edge of the basin. The high accuracy and precision measurements of CO<sub>2</sub> and CH<sub>4</sub> that are the focus of this presentation started in May 2018. Observations at Dahsiwo started in November 2019.For this presentation we focus on quantifying the magnitudes of CO<sub>2</sub> and CH<sub>4</sub> in urban-influenced air masses and their enhancements relative to clean background air. The correlations between CO<sub>2</sub> and CH<sub>4</sub> and their relationships to other air pollutant tracers including SO2, NOx/NOy, and CO provide constraints on potential sources for these gases. Through back trajectory analysis the source regions can be distinguished. As expected, both sites have enhanced mixing ratios of CO<sub>2</sub> and CH<sub>4</sub>. Median CO<sub>2</sub> during the overlapping period Nov. Dec. 2019 is 430, and 459 ppm at Miyun and Dashiwo. Median CH<sub>4</sub> is 2036 and 2228 ppb. Outside the growing season when CO<sub>2</sub> is influenced by vegetation uptake the CH<sub>4</sub>:CO<sub>2</sub> ratio is 6.1 ppb:ppm. The Dashiwo data are bounded by the same slope, but have more scatter due to periods with elevated CH<sub>4</sub> but not CO<sub>2</sub>. A tight correlation for CO<sub>2</sub> and CH<sub>4 </sub>at Miyun suggests a single predominant combustion or respiration source type, while variability in the Dashiwo observations suggests multiple sources including some rich in CH<sub>4</sub> that are not combustion or respiration. Identification of major CH<sub>4</sub> sources is a starting point for choosing mitigation options.</p>

scholarly journals Curiosity Mars methane measurements are not confused by ozone

2020 ◽  
Vol 641 ◽  
pp. L3 ◽  
Author(s):  
Christopher R. Webster ◽  
Paul R. Mahaffy ◽  
Sushil K. Atreya ◽  
Gregory J. Flesch ◽  
Charles A. Malespin ◽  
...  
Keyword(s):  
Spectral Resolution ◽  
Tunable Laser ◽  
Spectral Lines ◽  
Atmospheric Ozone ◽  
Sample Analysis ◽  
Noise Levels ◽  
Sample Cell ◽  
Laser Spectrometer ◽  
Upper Limits ◽  
Curiosity Rover

In the detection of methane in the atmosphere of Mars by the Tunable Laser Spectrometer on the Sample Analysis at Mars (TLS-SAM) on the Curiosity rover, the possibility of confusing ozone lines with those of methane is ruled out by the ultrahigh spectral resolution of the instrument. Even at the low background levels of methane (∼0.5 ppbv) detected by ingesting the atmosphere over a CO2 scrubber (Linde 13X) that enriches the methane abundance relative to CO2 by 25 times, the recorded TLS spectra show no presence of, and therefore no interference by, ozone lines. If O3 lines were to appear in the TLS spectra, they would be readily distinguishable from those of CH4. The inability of TLS-SAM to detect ozone spectral lines above its noise levels is consistent with a report that O3 decomposes in the presence of Linde 13X material, so that it would not arrive at the TLS sample cell in a significant quantity. With the exact enrichment factor for ozone undetermined, TLS-SAM is unable to produce meaningful upper limits to the atmospheric ozone abundance.

scholarly journals Enhanced stratospheric water vapor over the summertime continental United States and the role of overshooting convection

2017 ◽  
Vol 17 (9) ◽  
pp. 6113-6124 ◽  
Author(s):  
Robert L. Herman ◽  
Eric A. Ray ◽  
Karen H. Rosenlof ◽  
Kristopher M. Bedka ◽  
Michael J. Schwartz ◽  
...  
Keyword(s):  
United States ◽  
Water Vapor ◽  
Trajectory Analysis ◽  
The United States ◽  
Atmospheric Composition ◽  
Back Trajectory ◽  
Stratospheric Water Vapor ◽  
Mixing Ratios ◽  
The North ◽  
Back Trajectory Analysis

Abstract. The NASA ER-2 aircraft sampled the lower stratosphere over North America during the field mission for the NASA Studies of Emissions and Atmospheric Composition, Clouds and Climate Coupling by Regional Surveys (SEAC4RS). This study reports observations of convectively influenced air parcels with enhanced water vapor in the overworld stratosphere over the summertime continental United States and investigates three case studies in detail. Water vapor mixing ratios greater than 10 ppmv, which is much higher than the background 4 to 6 ppmv of the overworld stratosphere, were measured by the JPL Laser Hygrometer (JLH Mark2) at altitudes between 16.0 and 17.5 km (potential temperatures of approximately 380 to 410 K). Overshooting cloud tops (OTs) are identified from a SEAC4RS OT detection product based on satellite infrared window channel brightness temperature gradients. Through trajectory analysis, we make the connection between these in situ water measurements and OT. Back trajectory analysis ties enhanced water to OT 1 to 7 days prior to the intercept by the aircraft. The trajectory paths are dominated by the North American monsoon (NAM) anticyclonic circulation. This connection suggests that ice is convectively transported to the overworld stratosphere in OT events and subsequently sublimated; such events may irreversibly enhance stratospheric water vapor in the summer over Mexico and the United States. A regional context is provided by water observations from the Aura Microwave Limb Sounder (MLS).

Sign in / Sign up

Export Citation Format

Share Document