scholarly journals Bacteria in the global atmosphere – Part 2: Modeling of emissions and transport between different ecosystems

2009 ◽  
Vol 9 (23) ◽  
pp. 9281-9297 ◽  
Author(s):  
S. M. Burrows ◽  
T. Butler ◽  
P. Jöckel ◽  
H. Tost ◽  
A. Kerkweg ◽  
...  
Keyword(s):  
Seasonal Variation ◽  
Residence Time ◽  
General Circulation ◽  
Bacterial Species ◽  
Circulation Model ◽  
Cloud Condensation Nucleus ◽  
Cloud Formation ◽  
Emission Region ◽  
Culturable Bacteria ◽  
Bacterial Cells

Abstract. Bacteria are constantly being transported through the atmosphere, which may have implications for human health, agriculture, cloud formation, and the dispersal of bacterial species. We simulate the global transport of bacteria, represented as 1 μm and 3 μm diameter spherical solid particle tracers in a general circulation model. We investigate factors influencing residence time and distribution of the particles, including emission region, cloud condensation nucleus activity and removal by ice-phase precipitation. The global distribution depends strongly on the assumptions made about uptake into cloud droplets and ice. The transport is also affected, to a lesser extent, by the emission region, particulate diameter, and season. We find that the seasonal variation in atmospheric residence time is insufficient to explain by itself the observed seasonal variation in concentrations of particulate airborne culturable bacteria, indicating that this variability is mainly driven by seasonal variations in culturability and/or emission strength. We examine the potential for exchange of bacteria between ecosystems and obtain rough estimates of the flux from each ecosystem by using a maximum likelihood estimation technique, together with a new compilation of available observations described in a companion paper. Globally, we estimate the total emissions of bacteria-containing particles to the atmosphere to be 7.6×1023–3.5×1024 a−1, originating mainly from grasslands, shrubs and crops. We estimate the mass of emitted bacteria- to be 40–1800 Gg a−1, depending on the mass fraction of bacterial cells in the particles. In order to improve understanding of this topic, more measurements of the bacterial content of the air and of the rate of surface-atmosphere exchange of bacteria will be necessary. Future observations in wetlands, hot deserts, tundra, remote glacial and coastal regions and over oceans will be of particular interest.

scholarly journals Bacteria in the global atmosphere – Part 2: Modelling of emissions and transport between different ecosystems

2009 ◽  
Vol 9 (3) ◽  
pp. 10829-10881 ◽  
Author(s):  
S. M. Burrows ◽  
T. Butler ◽  
P. Jöckel ◽  
H. Tost ◽  
A. Kerkweg ◽  
...  
Keyword(s):  
Climate Model ◽  
Bacterial Species ◽  
Optimal Estimation ◽  
Companion Paper ◽  
Cloud Formation ◽  
Emission Region ◽  
Bacterial Cells ◽  
Cloud Droplets ◽  
Global Transport ◽  
Spherical Solid Particle

Abstract. Bacteria are constantly being transported through the atmosphere, which may have implications for human health, agriculture, cloud formation, and the dispersal of bacterial species. We simulated the global transport of bacterial cells, represented as 1μm diameter spherical solid particle tracers, in a chemistry-climate model. We investigated the factors influencing residence time and distribution of the particles, including emission region, CCN activity and removal by ice-phase precipitation. The global distribution depends strongly on the assumptions made about uptake into cloud droplets and ice. The transport is also affected, to a lesser extent, by the emission region and by season. We examine the potential for exchange of bacteria between ecosystems and obtain rough estimates of the flux from each ecosystem by using an optimal estimation technique, together with a new compilation of available observations described in a companion paper. Globally, we estimate the total emissions of bacteria to the atmosphere to be 1400 Gg per year with an upper bound of 4600 Gg per year, originating mainly from grasslands, shrubs and crops. In order to improve understanding of this topic, more measurements of the bacterial content of the air will be necessary. Future measurements in wetlands, sandy deserts, tundra, remote glacial and coastal regions and over oceans will be of particular interest.

scholarly journals Influence of gravity waves on the climatology of high-altitude Martian carbon dioxide ice clouds

2018 ◽  
Author(s):  
Erdal Yiğit ◽  
Alexander S. Medvedev ◽  
Paul Hartogh
Keyword(s):  
Carbon Dioxide ◽  
High Altitude ◽  
Gravity Waves ◽  
General Circulation ◽  
Middle Atmosphere ◽  
Circulation Model ◽  
Upper Atmosphere ◽  
Cloud Formation ◽  
Ice Clouds ◽  
Ice Cloud

Abstract. Carbon dioxide (CO2) ice clouds have been routinely observed in the middle atmosphere of Mars. However, there are still uncertainties concerning physical mechanisms that control their altitude, geographical, and seasonal distributions. Using the Max Planck Institute Martian General Circulation Model (MPI-MGCM), incorporating a state-of-the-art whole atmosphere subgrid-scale gravity wave parameterization (Yiğit et al., 2008), we demonstrate that internal gravity waves generated by lower atmospheric weather processes have wide reaching impact on the Martian climate. Globally, GWs cool the upper atmosphere of Mars by ~10 % and facilitate high-altitude CO2 ice cloud formation. CO2 ice cloud seasonal variations in the mesosphere and the mesopause region appreciably coincide with the spatio-temporal variations of GW effects, providing insight into the observed distribution of clouds. Our results suggest that GW propagation and dissipation constitute a necessary physical mechanism for CO2 ice cloud formation in the Martian upper atmosphere during all seasons.

scholarly journals Dynamics of the Coastal Oyashio and Its Seasonal Variation in a High-Resolution Western North Pacific Ocean Model

2010 ◽  
Vol 40 (6) ◽  
pp. 1283-1301 ◽  
Author(s):  
Kei Sakamoto ◽  
Hiroyuki Tsujino ◽  
Shiro Nishikawa ◽  
Hideyuki Nakano ◽  
Tatsuo Motoi
Keyword(s):  
Seasonal Variation ◽  
Pacific Ocean ◽  
North Pacific ◽  
General Circulation ◽  
Western North Pacific ◽  
North Pacific Ocean ◽  
Maximum Velocity ◽  
Circulation Model ◽  
Okhotsk Sea ◽  
Resolution Model

Abstract The Coastal Oyashio (CO) carries the cold, fresh, and relatively light water mass called the Coastal Oyashio Water (COW) westward along the southeastern coast of Hokkaido in winter and spring. To investigate dynamics of the CO and its seasonal variation, model experiments are executed using a western North Pacific general circulation model with horizontal resolutions of approximately 2 and 6 km. The 2-km resolution model reproduces the properties of COW with temperature of 0°–2°C and salinity of 32.2–32.6 and reproduces its distribution. COW is less dense than offshore water by 0.2 kg m−3, and it forms a surface-to-bottom density front with a width of 10 km near the shelf break. The CO appears as a baroclinic jet current along the front with a maximum velocity of approximately 40 cm s−1. The velocity and density structures and the front location relative to bathymetry indicate that the CO can be understood in terms of a simplified dynamical model developed for the shelfbreak front in the Middle Atlantic Bight. In contrast to the 2-km resolution model, the 6-km model cannot realistically reproduce the COW distribution. This is because only the 2-km model can represent the sharp density structure of the shelfbreak front and the accompanying CO. The CO exists during the limited period from January to April. This is directly connected with seasonal variation of the COW inflow from the Okhotsk Sea to the North Pacific Ocean through the Nemuro and Kunashiri Straits, indicating that the seasonal variation of the CO is ultimately controlled by the variation of the circulation in the Okhotsk Sea induced by the monsoon.

scholarly journals Diagnosing Warm Frontal Cloud Formation in a GCM: A Novel Approach Using Conditional Subsetting

2013 ◽  
Vol 26 (16) ◽  
pp. 5827-5845 ◽  
Author(s):  
James F. Booth ◽  
Catherine M. Naud ◽  
Anthony D. Del Genio
Keyword(s):  
General Circulation ◽  
Vertical Motion ◽  
Circulation Model ◽  
Precipitable Water ◽  
Satellite Observations ◽  
Local Fields ◽  
Cloud Formation ◽  
Initial Structure ◽  
Warm Front ◽  
Low Altitude

Abstract This study analyzes characteristics of clouds and vertical motion across extratropical cyclone warm fronts in the NASA Goddard Institute for Space Studies general circulation model. The validity of the modeled clouds is assessed using a combination of satellite observations from CloudSat, Cloud–Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO), Advanced Microwave Scanning Radiometer for Earth Observing System (AMSR-E), and the NASA Modern-Era Retrospective Analysis for Research and Applications (MERRA) reanalysis. The analysis focuses on developing cyclones, to test the model's ability to generate their initial structure. To begin, the extratropical cyclones and their warm fronts are objectively identified and cyclone-local fields are mapped into a vertical transect centered on the surface warm front. To further isolate specific physics, the cyclones are separated using conditional subsetting based on additional cyclone-local variables, and the differences between the subset means are analyzed. Conditional subsets are created based on 1) the transect clouds and 2) vertical motion; 3) the strength of the temperature gradient along the warm front, as well as the storm-local 4) wind speed and 5) precipitable water (PW). The analysis shows that the model does not generate enough frontal cloud, especially at low altitude. The subsetting results reveal that, compared to the observations, the model exhibits a decoupling between cloud formation at high and low altitudes across warm fronts and a weak sensitivity to moisture. These issues are caused in part by the parameterized convection and assumptions in the stratiform cloud scheme that are valid in the subtropics. On the other hand, the model generates proper covariability of low-altitude vertical motion and cloud at the warm front and a joint dependence of cloudiness on wind and PW.

Simulating Mars D/H and atmospheric chemistry during the 2018 Global Dust Storm and comparing with NOMAD observations

2020 ◽  
Author(s):  
Frank Daerden ◽  
Lori Neary ◽  
Geronimo Villanueva ◽  
Shohei Aoki ◽  
Sebastien Viscardy ◽  
...  
Keyword(s):  
Water Vapor ◽  
Atmospheric Chemistry ◽  
Dust Storm ◽  
General Circulation ◽  
Circulation Model ◽  
Cloud Formation ◽  
Vertical Profiles ◽  
Considerable Impact ◽  
Physical And Chemical ◽  
The Impact

<p>The NOMAD instrument suite on the ESA-Roskosmos ExoMars Trace Gas Orbiter (TGO) observes the physical and chemical composition of the Martian atmosphere with highly resolved vertical profiles and nadir sounding in the IR and UV-vis domains. Vertically resolved profiles of, amongst other species, water vapor, HDO, ozone, CO, CO<sub>2</sub>, oxygen airglow, dust and clouds were obtained for more than one Martian year [1-5]. During its first year of operations, NOMAD witnessed the 2018 Global Dust Storm (GDS) during its onset, peak and decline. The redistribution of water vapor to high altitudes and latitudes observed during the GDS was explained using the GEM-Mars General Circulation Model (GCM) [6-8]. The GCM was driven by the dust optical depths for Mars Year 34 provided by [9]. The photolysis products of water vapor are a major driver for the atmospheric chemistry on Mars. As water vapor is redistributed over the atmosphere, it is expected to have considerable impact on many other species. GEM-Mars contains routines for atmospheric chemistry and here we present some results of the simulated impact of the GDS on atmospheric chemistry and on several of the observed species. GEM-Mars now also includes the simulation of HDO and the fractionation of water vapor upon cloud formation. The simulations will be compared with the vertical profiles of the D/H ratio obtained from NOMAD observations. The impact of the GDS on D/H can be estimated from these simulations.</p><p>  </p><p>References</p><p> </p><p>[1] Vandaele, A. C. et al. (2019), Nature, 568, 7753, 521-525, doi: 10.1038/s41586-019-1097-3.</p><p>[2] Aoki, S. et al. (2019), J. Geophys. Res.: Planets, 124, 3482–3497. https://doi.org/10.1029/2019JE006109</p><p>[3] Gérard et al. (2020), Nature Astronomy, https://doi.org/10.1038/s41550-020-1123-2</p><p>[4] Villanueva et al., submitted.</p><p>[5] Korablev et al., 2020, in rev.</p><p>[6] Neary, L. and F. Daerden (2018), Icarus, 300, 458–476, https://doi.org/10.1016/j.icarus.2017.09.028</p><p>[7] Daerden, F. et al. (2019), Icarus, 326, 197-224, doi: 10.1016/j.icarus.2019.02.030.</p><p>[8] Neary, L. et al. (2020), Geophys. Res. Lett., 47, e2019GL084354. https://doi.org/10.1029/2019GL084354</p><p>[9] Montabone, L. et al. (2019), J. Geophys. Res.: Planets. doi: 10.1029/2019JE006111.</p><p> </p> <div>2.11.0.0</div><!-- COMO-HTML-CONTENT-END --> <div> <div>BIRA-IASB NOMAD team (continued):</div> <p>S. Robert (1), L. Trompet (1), A. Mahieux (1), C. Depiesse (1), E. Neefs (1) and B. Ristic (1).</p> </div> <!-- COMO-HTML-CONTENT-END --> <div class="co_mto_htmlabstract-teamMembers d-none d-md-block"> <div class="co_mto_htmlabstract-teamMembers-name h1-special journal-contentHeaderColor header-element color-primary">BIRA-IASB NOMAD team (continued):</div> <p>S. Robert (1), L. Trompet (1), A. Mahieux (1), C. Depiesse (1), E. Neefs (1) and B. Ristic (1).</p> </div> <p class="co_mto_htmlabstract-citationHeader"> <strong class="co_mto_htmlabstract-citationHeader-intro">How to cite:</strong> Daerden, F., Neary, L., Villanueva, G., Aoki, S., Viscardy, S., Thomas, I., Vandaele, A. C., Liuzzi, G., Crismani, M., Khayat, A., Smith, M. D., Clancy, R. T., Wolff, M. J., Sandor, B. J., Whiteway, J. A., Mumma, M. J., Erwin, J., Willame, Y., and Piccialli, A. and the BIRA-IASB NOMAD team (continued): Simulating Mars D/H and atmospheric chemistry during the 2018 Global Dust Storm and comparing with NOMAD observations , Europlanet Science Congress 2020, online, 21 September–9 Oct 2020, EPSC2020-371, 2020 </p>

scholarly journals Seasonal Variation of the Seychelles Dome

2008 ◽  
Vol 21 (15) ◽  
pp. 3740-3754 ◽  
Author(s):  
Takaaki Yokoi ◽  
Tomoki Tozuka ◽  
Toshio Yamagata
Keyword(s):  
Seasonal Variation ◽  
Indian Ocean ◽  
Wind Stress ◽  
Zonal Wind ◽  
General Circulation ◽  
Indian Monsoon ◽  
Circulation Model ◽  
The Other ◽  
Boreal Summer ◽  
Zonal Wind Stress

Abstract Using an ocean general circulation model (OGCM), seasonal variation of the Seychelles Dome (SD) is investigated for the first time. The SD is an oceanic thermal dome located in the southwestern Indian Ocean, and its influence on sea surface temperature is known to play an important role in the Indian monsoon system. Its seasonal variation is dominated by a remarkable semiannual cycle resulting from local Ekman upwelling. This semiannual nature is explained by different contributions of the following two components of the Ekman pumping: one term that is proportional to the planetary beta and the zonal wind stress and the other term that is proportional to the wind stress curl. The former is determined by the seasonal change in the zonal component of the wind stress vector above the SD; it is associated with the Indian monsoon and causes downwelling (upwelling) during boreal summer (boreal winter). The latter, whose major contribution comes from the meridional gradient of the zonal wind stress, also shows a clear annual cycle with strong upwelling during boreal summer and fall. However, it remains almost constant for 5 months from June to October, even though the zonal wind stress itself varies significantly during this period. The above overall feature is due to the unique location of the SD; it is located between the following two regions: one is dominated by the seasonal variation in wind stress resulting from the Indian monsoon, and the other is dominated by the southeasterly trade winds that prevail throughout a year. The above uniqueness provides a novel mechanism that causes the strong semiannual cycle in the tropical Indian Ocean.

scholarly journals A Numerical Investigation of the Berg Feature on Uranus as a Vortex-Driven System

Atmosphere ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 52
Author(s):  
Raymond LeBeau ◽  
Kevin Farmer ◽  
Ramanakumar Sankar ◽  
Nathan Hadland ◽  
Csaba Palotai
Keyword(s):  
Numerical Investigation ◽  
General Circulation Model ◽  
General Circulation ◽  
Circulation Model ◽  
Cloud Formation ◽  
Vortex System ◽  
Vortex Control ◽  
Driven System ◽  
The Creation ◽  
South Polar

The Berg cloud feature in the atmosphere of Uranus was first identified as a persistent grouping of clouds located just off the bright South Polar Collar at a latitude of around −34 degrees. Ongoing observations of this feature through the 1990s and 2000s suggested that the feature was oscillating in location by a few degrees in latitude for several years, and then unexpectedly began to drift towards the equator, which continued over the final 4 years until the cloud dissipated. One possible explanation for such a persistent drifting cloud is that it is a cloud-vortex system, in which an unseen vortex drives the creation of the cloud and the motions of the vortex control the cloud location. To explore this possibility, a series of vortices are studied numerically using the Explicit Planetary Isentropic Coordinate General Circulation Model (EPIC GCM). The evolution of these test vortices are simulated to examine their drift rates and the potential for cloud formation. The results indicate that conditions on Uranus could result in an equatorward drifting vortex over a range of latitudes and that significant cloud formation could occur, potentially obscuring observations of the vortex.

Sign in / Sign up

Export Citation Format

Share Document