Investigating the Dynamics of Hothouse Earth Climates with a Simplified GCM

2020 ◽  
Author(s):  
Matthew McKinney ◽  
Jonathan Mitchell
Keyword(s):  
Large Scale ◽  
Hadley Cell ◽  
Three Dimensions ◽  
Status Report ◽  
Atmospheric Moisture ◽  
Surface Liquid ◽  
The Tropics ◽  
Large Scale Atmospheric Circulation ◽  
Atmospheric Moisture Content ◽  
Saturation Vapor

<p>There are records of past Earth climates that were ice-free all the way to the poles (Barron 1983), which can be described as “hothouse” climates. These hothouse climates can be contrasted with an “all-tropics” planet, where the tropics are defined by the atmospheric dynamics, i.e. the Hadley Cell extent (Faulk et al. 2017). This classification is thus primarily dependent on a planet’s rotation, rather than its ice-free extent or surface temperatures. We investigate the parameter space between Earth and an all-tropics world using the open-source GCM Isca, developed by Vallis et al (2018). We take an Earth analog and perform a parameter sweep in three dimensions: global reservoir depth (1000m, 100m, 10m, 1m, 1cm); global saturation vapor pressure (1.5x current, 1.4x, 1.3x, 1.2x, 1.1x, 1x); and rotation rate (16 days, 8 days, 1 day). The sweep will allow us to explore the effects of surface liquid coverage, atmospheric moisture content, and large-scale atmospheric circulation on an Earth-like climate. In this presentation we provide a status report and analysis of initial findings.</p>

scholarly journals The Role of the Divergent Circulation for Large-Scale Eddy Momentum Transport in the Tropics. Part I: Observations

2019 ◽  
Vol 76 (4) ◽  
pp. 1125-1144 ◽  
Author(s):  
Pablo Zurita-Gotor
Keyword(s):  
Momentum Flux ◽  
Large Scale ◽  
Zonal Flow ◽  
Stationary Wave ◽  
Hadley Cell ◽  
Momentum Transport ◽  
Mean Flow ◽  
Meridional Transport ◽  
The Tropics

Abstract This work investigates the role played by the divergent circulation for meridional eddy momentum transport in the tropical atmosphere. It is shown that the eddy momentum flux in the deep tropics arises primarily from correlations between the divergent eddy meridional velocity and the rotational eddy zonal velocity. Consistent with previous studies, this transport is dominated by the stationary wave component, associated with correlations between the zonal structure of the Hadley cell (zonal anomalies in the meridional overturning) and the climatological-mean Rossby gyres. This eddy momentum flux decomposition implies a different mechanism of eddy momentum convergence from the extratropics, associated with upper-level mass convergence (divergence) over sectors with anomalous westerlies (easterlies). By itself, this meridional transport would only increase (decrease) isentropic thickness over regions with anomalous westerly (easterly) zonal flow. The actual momentum mixing is due to vertical (cross isentropic) advection, pointing to the key role of diabatic processes for eddy–mean flow interaction in the tropics.

scholarly journals On the Linkage between the Extreme Drought and Pluvial Patterns in China and the Large-Scale Atmospheric Circulation

2016 ◽  
Vol 2016 ◽  
pp. 1-12 ◽  
Author(s):  
Zengxin Zhang ◽  
Qiu Jin ◽  
Xi Chen ◽  
Chong-Yu Xu ◽  
Shanshan Jiang
Keyword(s):  
Atmospheric Circulation ◽  
South China ◽  
Large Scale ◽  
North China ◽  
Western Pacific Subtropical High ◽  
Extreme Drought ◽  
Height Anomaly ◽  
Monthly Precipitation ◽  
Atmospheric Moisture ◽  
Large Scale Atmospheric Circulation

China is a nation that is affected by a multitude of natural disasters, including droughts and floods. In this paper, the variations of extreme drought and pluvial patterns and their relations to the large-scale atmospheric circulation have been analyzed based on monthly precipitation data from 483 stations during the period 1958–2010 in China. The results show the following:(1)the extreme drought and pluvial events in China increase significantly during that period. During 1959–1966 timeframe, more droughts occur in South China and more pluvial events are found in North China (DSC-PNC pattern); as for the period 1997–2003 (PSC-DNC pattern), the situation is the opposite.(2)There are good relationships among the extreme drought and pluvial events and the Western Pacific Subtropical High, meridional atmospheric moisture flux, atmospheric moisture content, and summer precipitation.(3)A cyclone atmospheric circulation anomaly occurs in North China, followed by an obvious negative height anomaly and a southern wind anomaly at 850 hPa and 500 hPa for the DSC-PNC pattern during the summer, and a massive ascending airflow from South China extends to North China at ~50∘N. As for the PSC-DNC pattern, the situation contrasts sharply with the DSC-PNC pattern.

scholarly journals A vertical wind structure that leads to extreme rainfall and major flooding in southeast Australia

2016 ◽  
Vol 66 (4) ◽  
pp. 380
Author(s):  
Jeff Callaghan ◽  
Scott B. Power
Keyword(s):  
Coastal Zone ◽  
Heavy Rainfall ◽  
Extreme Rainfall ◽  
Analysis Data ◽  
Atmospheric Moisture ◽  
Southeastern Australia ◽  
Wind Structure ◽  
Eastern Australia ◽  
The Tropics ◽  
Atmospheric Moisture Content

Here we examine winds associated with extreme rainfall and major flooding in coastal catchments and more broadly over southeastern Australia. Both radio-sonde and re-analysis data are examined. In every case (i) atmospheric moisture content is high and (ii) the low-level winds are onshore, and in almost every case (iii) the wind-direction turns anti-cyclonically with increasing height up to 500 hPa. Data from Brisbane extending back more than 50 years is consistent with this behavior: winds turn anti-cyclonically with increasing height on days with heavy rainfall, whereas winds turn cyclonically with increasing height on days with light or no rainfall. In the coastal zone, extreme rainfall rarely occurs without (i), (ii) and (iii). In eastern Australia beyond the coastal zone, conditions (i) and (iii) are also associated with extreme rainfall. We found very few cases where such conditions were not associated with extreme rainfall in this broader region. This study extends previous work by showing that the link between turning winds and rainfall exists in both the tropics and subtropics, and the link applies in cases of extreme rainfall and associated major flooding.

The large-scale tilt of the eddy divergence in the tropics

2020 ◽  
Author(s):  
Pablo Zurita-Gotor
Keyword(s):  
Momentum Flux ◽  
Large Scale ◽  
Hadley Cell ◽  
Coarse Grained ◽  
Wave Source ◽  
Summer Hemisphere ◽  
Divergence Field ◽  
Upper Level ◽  
The Tropics

<p>This work is concerned with the large-scale structure of the upper-level divergence/precipitation field in the deep tropics. Once the fine ITCZ structure is filtered out, the coarse-grained eddy divergence field is found to tilt eastward moving away from its maximum near the equator in the summer hemisphere. This robust tilt (observed for both hemispheres and seasons) is also present in the classical Gill solution.</p><p>In this presentation we show that the sign of the tilt is intimately linked to the direction of the eddy momentum flux. The observed eastward tilt is such that the momentum flux is directed towards the wave source, suggesting that the observed tilt is determined by wave propagation.</p><p>We also discuss the determination of the tilt in the simple Gill model and its sensitivity to the meridional Hadley flow. We show that the increase in the cross-equatorial momentum flux when the Hadley cell strengthens is associated with an increased tilt of the divergence field in the downstream direction of the flow, supporting the conjecture that the tilt is associated with propagation. </p>

New Models of Content Creation and Scholarship at the Intersection of Library Spaces, Technologies, and Expertise

2018 ◽  
Author(s):  
Mike Nutt ◽  
Gregory Raschke
Keyword(s):  
Large Scale ◽  
Interactive Media ◽  
Scholarly Communication ◽  
Three Dimensions ◽  
Organizational Capabilities ◽  
High Definition ◽  
Content Creation ◽  
Full Life Cycle ◽  
Digital Scholarship ◽  
Digital Objects

Library spaces that blend collaboration areas, advanced technologies, and librarian expertise are creating new modes of scholarly communication. These spaces enable scholarship created within high-definition, large-scale visual collaborative environments. This emergent model of scholarly communication can be experienced within those specific contexts or through digital surrogates on the networked Web. From experiencing in three dimensions the sermons of John Donne in 1622 to interactive media interpretations of American wars, scholars are partnering with libraries to create immersive digital scholarship. Viewing the library as a research platform for these emergent forms of digital scholarship presents several opportunities and challenges. Opportunities include re-engaging faculty in the use of library space, integrating the full life-cycle of the research enterprise, and engaging broad communities in the changing nature of digitally-driven scholarship. Issues such as identifying and filtering collaborations, strategically managing staff resources, creating surrogates of immersive digital scholarship, and preserving this content for the future present an array of challenges for libraries that require coordination across organizations. From engaging and using high-technology spaces to documenting the data and digital objects created, this developing scholarly communication medium brings to bear the multifaceted skills and organizational capabilities of libraries.

scholarly journals Extreme Floods in the Eastern Part of Europe: Large-Scale Drivers and Associated Impacts

Water ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1122
Author(s):  
Monica Ionita ◽  
Viorica Nagavciuc
Keyword(s):  
Water Vapor ◽  
Heavy Rainfall ◽  
Large Scale ◽  
Vapor Transport ◽  
Water Vapor Transport ◽  
Flood Events ◽  
Rainfall Events ◽  
Catchment Areas ◽  
Large Scale Atmospheric Circulation ◽  
Heavy Rainfall Events

The role of the large-scale atmospheric circulation in producing heavy rainfall events and floods in the eastern part of Europe, with a special focus on the Siret and Prut catchment areas (Romania), is analyzed in this study. Moreover, a detailed analysis of the socio-economic impacts of the most extreme flood events (e.g., July 2008, June–July 2010, and June 2020) is given. Analysis of the largest flood events indicates that the flood peaks have been preceded up to 6 days in advance by intrusions of high Potential Vorticity (PV) anomalies toward the southeastern part of Europe, persistent cut-off lows over the analyzed region, and increased water vapor transport over the catchment areas of Siret and Prut Rivers. The vertically integrated water vapor transport prior to the flood peak exceeds 300 kg m−1 s−1, leading to heavy rainfall events. We also show that the implementation of the Flood Management Plan in Romania had positive results during the 2020 flood event compared with the other flood events, when the authorities took several precaution measurements that mitigated in a better way the socio-economic impact and risks of the flood event. The results presented in this study offer new insights regarding the importance of large-scale atmospheric circulation and water vapor transport as drivers of extreme flooding in the eastern part of Europe and could lead to a better flood forecast and flood risk management.

scholarly journals Global climatology and trends in convective environments from ERA5 and rawinsonde data

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Mateusz Taszarek ◽  
John T. Allen ◽  
Mattia Marchio ◽  
Harold E. Brooks
Keyword(s):  
Large Scale ◽  
Climate Models ◽  
Global Climate ◽  
Convective Available Potential Energy ◽  
Global Climate Models ◽  
Convective Precipitation ◽  
The Past ◽  
The Tropics ◽  
Rawinsonde Data

AbstractGlobally, thunderstorms are responsible for a significant fraction of rainfall, and in the mid-latitudes often produce extreme weather, including large hail, tornadoes and damaging winds. Despite this importance, how the global frequency of thunderstorms and their accompanying hazards has changed over the past 4 decades remains unclear. Large-scale diagnostics applied to global climate models have suggested that the frequency of thunderstorms and their intensity is likely to increase in the future. Here, we show that according to ERA5 convective available potential energy (CAPE) and convective precipitation (CP) have decreased over the tropics and subtropics with simultaneous increases in 0–6 km wind shear (BS06). Conversely, rawinsonde observations paint a different picture across the mid-latitudes with increasing CAPE and significant decreases to BS06. Differing trends and disagreement between ERA5 and rawinsondes observed over some regions suggest that results should be interpreted with caution, especially for CAPE and CP across tropics where uncertainty is the highest and reliable long-term rawinsonde observations are missing.

scholarly journals Large-scale screening of natural genetic resource in the hydrocarbon-producing microalga Botrycoccus braunii identified novel fast-growing strains

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Koji Kawamura ◽  
Suzune Nishikawa ◽  
Kotaro Hirano ◽  
Ardianor Ardianor ◽  
Rudy Agung Nugroho ◽  
...  
Keyword(s):  
Large Scale ◽  
Biomass Productivity ◽  
Botryococcus Braunii ◽  
Algal Biofuel ◽  
Fast Growing ◽  
Wild Strains ◽  
Glass Tubes ◽  
The Tropics ◽  
Large Scale Screening ◽  
Hydrocarbon Productivity

AbstractAlgal biofuel research aims to make a renewable, carbon–neutral biofuel by using oil-producing microalgae. The freshwater microalga Botryococcus braunii has received much attention due to its ability to accumulate large amounts of petroleum-like hydrocarbons but suffers from slow growth. We performed a large-scale screening of fast-growing strains with 180 strains isolated from 22 ponds located in a wide geographic range from the tropics to cool-temperate. A fast-growing strain, Showa, which recorded the highest productivities of algal hydrocarbons to date, was used as a benchmark. The initial screening was performed by monitoring optical densities in glass tubes and identified 9 wild strains with faster or equivalent growth rates to Showa. The biomass-based assessments showed that biomass and hydrocarbon productivities of these strains were 12–37% and 11–88% higher than that of Showa, respectively. One strain, OIT-678 established a new record of the fastest growth rate in the race B strains with a doubling time of 1.2 days. The OIT-678 had 36% higher biomass productivity, 34% higher hydrocarbon productivity, and 20% higher biomass density than Showa at the same cultivation conditions, suggesting the potential of the new strain to break the record for the highest productivities of hydrocarbons.

scholarly journals Dipole patterns in tropical precipitation were pervasive across landmasses throughout Marine Isotope Stage 5

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Katrina Nilsson-Kerr ◽  
Pallavi Anand ◽  
Philip B. Holden ◽  
Steven C. Clemens ◽  
Melanie J. Leng
Keyword(s):  
Large Scale ◽  
Marine Isotope Stage ◽  
Convergence Zone ◽  
Inter Tropical Convergence Zone ◽  
Tropical Regions ◽  
Tropical Precipitation ◽  
Rainfall Patterns ◽  
Marine Isotope Stage 5 ◽  
Climate Cooling ◽  
The Tropics

AbstractMost of Earth’s rain falls in the tropics, often in highly seasonal monsoon rains, which are thought to be coupled to the inter-hemispheric migrations of the Inter-Tropical Convergence Zone in response to the seasonal cycle of insolation. Yet characterization of tropical rainfall behaviour in the geologic past is poor. Here we combine new and existing hydroclimate records from six large-scale tropical regions with fully independent model-based rainfall reconstructions across the last interval of sustained warmth and ensuing climate cooling between 130 to 70 thousand years ago (Marine Isotope Stage 5). Our data-model approach reveals large-scale heterogeneous rainfall patterns in response to changes in climate. We note pervasive dipole-like tropical precipitation patterns, as well as different loci of precipitation throughout Marine Isotope Stage 5 than recorded in the Holocene. These rainfall patterns cannot be solely attributed to meridional shifts in the Inter-Tropical Convergence Zone.

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