scholarly journals Temperatures of Anvil Clouds and Radiative Tropopause in a Wide Array of Cloud-Resolving Simulations

2021 ◽  
Author(s):  
Seth Seidel ◽  
Da Yang
Keyword(s):  
Climate Change ◽  
Radiative Transfer ◽  
Surface Temperature ◽  
Greenhouse Gas ◽  
Climate Warming ◽  
Gas Concentration ◽  
Surface Warming ◽  
Ozone Profile ◽  
Simulation Results ◽  
Tropopause Temperature

We present ninety-nine cloud-resolving simulations to study how temperatures of anvil clouds and radiative tropopause change with surface warming. Our simulation results show that the radiative tropopause warms at approximately the same rate as anvil clouds. This relationship persists across a variety of modeling choices, including surface temperature, greenhouse gas concentration, and the representation of radiative transfer. We further show that the shifting ozone profile associated with climate warming may give rise to a fixed tropopause temperature as well as a fixed anvil temperature. This result points to the importance of faithful treatment of ozone in simulating clouds and climate change; the robust anvil-tropopause relationship may also provide alternative ways to understand what controls anvil temperature.

scholarly journals Heat stress risk in European dairy cattle husbandry under different climate change scenarios – uncertainties and potential impacts

2019 ◽  
Author(s):  
Sabrina Hempel ◽  
Christoph Menz ◽  
Severino Pinto ◽  
Elena Galán ◽  
David Janke ◽  
...  
Keyword(s):  
Climate Change ◽  
Heat Stress ◽  
Dairy Cattle ◽  
Animal Welfare ◽  
Greenhouse Gas ◽  
Milk Yield ◽  
Climate Model ◽  
Stress Conditions ◽  
Gas Concentration ◽  
Cattle Husbandry

Abstract. In the last decades, an exceptional global warming trend was observed. Along with the temperature increase, modifications in the humidity and wind regime amplify the regional and local impacts on livestock husbandry. Direct impacts include the occurrence of climatic stress conditions. In Europe, cows are economically highly relevant and are mainly kept in naturally ventilated buildings that are most susceptible to climate change. The high-yielding cows are particularly vulnerable to heat stress. Modifications in housing management are the main measures taken to improve the ability of livestock to cope with these conditions. Measures are, however, typically taken in direct reaction to uncomfortable conditions instead of in anticipation of a long term risk for climatic stress. Moreover, measures that balance welfare, environmental and economic issues are barely investigated in the context of climate change and are thus almost not available for commercial farms. Quantitative analysis of the climate change impacts on the animal welfare and linked economic and environmental factors are rare. Therefore, we used a numerical modeling approach to estimate the future heat stress risk in such dairy cattle husbandry systems. The indoor climate was monitored inside three reference barns in Central Europe and in the Mediterranean region. An artificial neuronal network (ANN) was trained to relate the outdoor weather conditions provided by official meteorological weather stations to the measured indoor microclimate. Subsequently, this ANN model was driven by an ensemble of regional climate model projections with three different greenhouse gas concentration scenarios. For the evaluation of the heat stress risk, we considered the amount and duration of heat stress events. Based on the changes of the heat stress events various economic and environmental impacts were estimated. We found that the impacts of the projected increase of heat stress risk vary dependent on the region respectively the barn, the climate model and the assumed greenhouse gas concentration. There was an overall increasing trend in number and duration of heat stress events. At the end of the century, the number of annual stress events can be expected to increase by up to 2000 hours while the average duration of the events increases by up to 22 h compared to the end of the last century. This implies strong impacts on economics, environment and animal welfare and an urgent need for mid-term adaptation strategies. We anticipated that up to one tenth of all hours of a year respectively one third of all days will be classified as critical heat stress conditions. Due to heat stress, milk yield may decrease by about 3.5 % relative to the present European milk yield and farmers may expect financial losses in the summer season of about 6.6 % of their monthly income. In addition, an increasing demand for emission reduction measures must be expected, as an emission increase of about 16 Gg ammonia and 0.1 Gg methane per year can be expected under the anticipated heat stress conditions. The cattle respiration rate increases by up to 60 % and the standing time may be prolonged by 1 h. This promotes health issues and increases the probability of medical treatments. The various impacts imply feedback loops in the climate system which are presently underexplored. Hence, future in-depth studies on the different impacts and adaptation options at different stress levels are highly recommended.

scholarly journals Arctic Climate Variability and Trends from Satellite Observations

2012 ◽  
Vol 2012 ◽  
pp. 1-22 ◽  
Author(s):  
Xuanji Wang ◽  
Jeffrey Key ◽  
Yinghui Liu ◽  
Charles Fowler ◽  
James Maslanik ◽  
...  
Keyword(s):  
Climate Change ◽  
Sea Ice ◽  
Surface Temperature ◽  
Cloud Fraction ◽  
Arctic Sea Ice ◽  
Satellite Observations ◽  
Arctic Climate ◽  
The Arctic ◽  
Climate Indices ◽  
Surface Warming

Arctic climate has been changing rapidly since the 1980s. This work shows distinctly different patterns of change in winter, spring, and summer for cloud fraction and surface temperature. Satellite observations over 1982–2004 have shown that the Arctic has warmed up and become cloudier in spring and summer, but cooled down and become less cloudy in winter. The annual mean surface temperature has increased at a rate of 0.34°C per decade. The decadal rates of cloud fraction trends are −3.4%, 2.3%, and 0.5% in winter, spring, and summer, respectively. Correspondingly, annually averaged surface albedo has decreased at a decadal rate of −3.2%. On the annual average, the trend of cloud forcing at the surface is −2.11 W/m2per decade, indicating a damping effect on the surface warming by clouds. The decreasing sea ice albedo and surface warming tend to modulate cloud radiative cooling effect in spring and summer. Arctic sea ice has also declined substantially with decadal rates of −8%, −5%, and −15% in sea ice extent, thickness, and volume, respectively. Significant correlations between surface temperature anomalies and climate indices, especially the Arctic Oscillation (AO) index, exist over some areas, implying linkages between global climate change and Arctic climate change.

scholarly journals Climate warming from managed grasslands cancels the cooling effect of carbon sinks in sparsely grazed and natural grasslands

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Jinfeng Chang ◽  
Philippe Ciais ◽  
Thomas Gasser ◽  
Pete Smith ◽  
Mario Herrero ◽  
...  
Keyword(s):  
Climate Change ◽  
Greenhouse Gas ◽  
Nitrogen Deposition ◽  
Climate Warming ◽  
Radiative Forcing ◽  
Future Climate Change ◽  
Surface Model ◽  
Carbon Sinks ◽  
Regional Patterns ◽  
Natural Grasslands

AbstractGrasslands absorb and release carbon dioxide (CO2), emit methane (CH4) from grazing livestock, and emit nitrous oxide (N2O) from soils. Little is known about how the fluxes of these three greenhouse gases, from managed and natural grasslands worldwide, have contributed to past climate change, or the roles of managed pastures versus natural grasslands. Here, global trends and regional patterns of the full greenhouse gas balance of grasslands are estimated for the period 1750 to 2012. A new spatially explicit land surface model is applied, to separate the direct effects of human activities from land management and the indirect effects from climate change, increasing CO2 and regional changes in nitrogen deposition. Direct human management activities are simulated to have caused grasslands to switch from a sink to a source of greenhouse gas, because of increased livestock numbers and accelerated conversion of natural lands to pasture. However, climate change drivers contributed a net carbon sink in soil organic matter, mainly from the increased productivity of grasslands due to increased CO2 and nitrogen deposition. The net radiative forcing of all grasslands is currently close to neutral, but has been increasing since the 1960s. Here, we show that the net global climate warming caused by managed grassland cancels the net climate cooling from carbon sinks in sparsely grazed and natural grasslands. In the face of future climate change and increased demand for livestock products, these findings highlight the need to use sustainable management to preserve and enhance soil carbon storage in grasslands and to reduce greenhouse gas emissions from managed grasslands.

scholarly journals Suitability of Habitats in Nepal for Dactylorhiza hatagirea Now and under Predicted Future Changes in Climate

Plants ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 467
Author(s):  
Bikram Shrestha ◽  
Spyros Tsiftsis ◽  
Deep Jyoti Chapagain ◽  
Chhatra Khadka ◽  
Prakash Bhattarai ◽  
...  
Keyword(s):  
Climate Change ◽  
Greenhouse Gas ◽  
Suitable Habitat ◽  
Case Scenario ◽  
Worst Case ◽  
Change Models ◽  
Gas Concentration ◽  
Wild Fauna ◽  
Suitable Habitats ◽  
Increasing Temperature

Dactylorhiza hatagirea is a terrestrial orchid listed in Appendix II of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) and classified as threatened by International Union for Conservation of Nature (IUCN). It is endemic to the Hindu-Kush Himalayan region, distributed from Pakistan to China. The main threat to its existence is climate change and the associated change in the distribution of its suitable habitats to higher altitudes due to increasing temperature. It is therefore necessary to determine the habitats that are suitable for its survival and their expected distribution after the predicted changes in climate. To do this, we use Maxent modelling of the data for its 208 locations. We predict its distribution in 2050 and 2070 using four climate change models and two greenhouse gas concentration trajectories. This revealed severe losses of suitable habitat in Nepal, in which, under the worst scenario, there will be a 71–81% reduction the number of suitable locations for D. hatagirea by 2050 and 95–98% by 2070. Under the most favorable scenario, this reduction will be 65–85% by 2070. The intermediate greenhouse gas concentration trajectory surprisingly would result in a greater reduction by 2070 than the worst-case scenario. Our results provide important guidelines that local authorities interested in conserving this species could use to select areas that need to be protected now and in the future.

Climate Response at the Paleocene–Eocene Thermal Maximum to Greenhouse Gas Forcing—A Model Study with CCSM3

2010 ◽  
Vol 23 (10) ◽  
pp. 2562-2584 ◽  
Author(s):  
A. Winguth ◽  
C. Shellito ◽  
C. Shields ◽  
C. Winguth
Keyword(s):  
Climate Change ◽  
Surface Temperature ◽  
Greenhouse Gas ◽  
Methane Hydrate ◽  
Atmospheric Co2 ◽  
Future Climate Change ◽  
High Latitudes ◽  
Co2 Concentrations ◽  
Thermal Maximum ◽  
Atmospheric Co2 Concentrations

Abstract The Paleocene–Eocene Thermal Maximum (PETM; 55 Ma) is of particular interest since it is regarded as a suitable analog to future climate change. In this study, the PETM climate is investigated using the Community Climate System Model (CCSM3) with atmospheric CO2 concentrations of 4×, 8×, and 16× the preindustrial value. Simulated climate change from 4× to 8× atmospheric CO2 concentration, possibly corresponding to an environmental precursor of the PETM event, leads to a warming of the North Atlantic Ocean Intermediate-Water masses, thus lowering the critical depth for methane hydrate destabilization by ∼500 m. A further increase from 8× to 16×CO2, analogous to a possible massive methane hydrate release, results in global oceanic warming and stratification. The increase in the radiative surface warming, especially at high latitudes, is partially offset by a decrease in the ocean heat transport due to a reduced overturning circulation. Surface temperature values simulated in the 16×CO2 PETM run represent the closest match to surface temperature reconstructions from proxies for this period. Simulated PETM precipitation, characterized by a slight northward shift of the intertropical convergence zone, increases at higher CO2 concentrations, especially for the northern midlatitudes as well as the high latitudes in both hemispheres. Data-inferred precipitation values and gradients for North America and Spain, for instance, are in good agreement with the 16×CO2 simulation. Increasing atmospheric CO2 concentrations might also have favored the release of terrestrial methane through warmer and wetter conditions over land, thus reinforcing the greenhouse gas concentration increase.

The Impact of Climate Change on Air Quality–Related Meteorological Conditions in California. Part I: Present Time Simulation Analysis

2011 ◽  
Vol 24 (13) ◽  
pp. 3344-3361 ◽  
Author(s):  
Zhan Zhao ◽  
Shu-Hua Chen ◽  
Michael J. Kleeman ◽  
Mary Tyree ◽  
Dan Cayan
Keyword(s):  
Climate Change ◽  
Air Quality ◽  
Surface Temperature ◽  
Climate Model ◽  
Global Climate ◽  
Global Climate Model ◽  
Surface Wind ◽  
Valley Wind ◽  
Simulation Results ◽  
The Impact

Abstract This study investigates the impacts of climate change on meteorology and air quality conditions in California by dynamically downscaling Parallel Climate Model (PCM) data to high resolution (4 km) using the Weather Research and Forecast (WRF) model. This paper evaluates the present years’ (2000–06) downscaling results driven by either PCM or National Centers for Environmental Prediction (NCEP) Global Forecasting System (GFS) reanalysis data. The analyses focused on the air quality–related meteorological variables, such as planetary boundary layer height (PBLH), surface temperature, and wind. The differences of the climatology from the two sets of downscaling simulations and the driving global datasets were compared, which illustrated that most of the biases of the downscaling results were inherited from the driving global climate model (GCM). The downscaling process added mesoscale features but also introduced extra biases into the driving global data. The main source of bias in the PCM data is an imprecise prediction of the location and strength of the Pacific subtropical high (PSH). The analysis implied that using simulation results driven by PCM data as the input for air quality models will likely underestimate air pollution problems in California. Regional-averaged statistics of the downscaling results were estimated for two highly polluted areas, the South Coast Air Basin (SoCAB) and the San Joaquin Valley (SJV), by comparing to observations. The simulations driven by GFS data overestimated surface temperature and wind speed for most of the year, indicating that WRF has systematic errors in these two regions. The simulation matched the observations better during summer than winter in terms of bias. WRF has difficulty reproducing weak surface wind, which normally happens during stagnation events in these two regions. The shallow summer PBLH in the Central Valley is caused by the dominance of high pressure systems over the valley and the strong valley wind during summer. The change of meteorology and air quality in California due to climate change will be explored in Part II of this study, which compares the future (2047–53) and present (2000–06) simulation results driven by PCM data and is presented in a separate paper.

scholarly journals Influences of Local and Remote Conditions on Tropical Precipitation and Its Response to Climate Change

2020 ◽  
Vol 33 (10) ◽  
pp. 4045-4063
Author(s):  
Marion Saint-Lu ◽  
Robin Chadwick ◽  
F. Hugo Lambert ◽  
Matthew Collins ◽  
Ian Boutle ◽  
...  
Keyword(s):  
Climate Change ◽  
Surface Temperature ◽  
General Circulation ◽  
Large Scale ◽  
Circulation Pattern ◽  
General Circulation Models ◽  
Overturning Circulation ◽  
Surface Warming ◽  
Single Column ◽  
Precipitation Changes

AbstractBy comparing a single-column model (SCM) with closely related general circulation models (GCMs), precipitation changes that can be diagnosed from local changes in surface temperature (TS) and relative humidity (RHS) are separated from more complex responses. In the SCM setup, the large-scale tropical circulation is parameterized to respond to the surface temperature departure from a prescribed environment, following the weak temperature gradient (WTG) approximation and using the damped gravity wave (DGW) parameterization. The SCM is also forced with moisture variations. First, it is found that most of the present-day mean tropical rainfall and circulation pattern is associated with TS and RHS patterns. Climate change experiments with the SCM are performed, imposing separately surface warming and CO2 increase. The rainfall responses to future changes in sea surface temperature patterns and plant physiology are successfully reproduced, suggesting that these are direct responses to local changes in convective instability. However, the SCM increases oceanic rainfall too much, and fails to reproduce the land rainfall decrease, both of which are associated with uniform ocean warming. It is argued that remote atmospheric teleconnections play a crucial role in both weakening the atmospheric overturning circulation and constraining precipitation changes. Results suggest that the overturning circulation weakens, both as a direct local response to increased CO2 and in response to energy-imbalance driven exchanges between ascent and descent regions.

scholarly journals Influence of the Atlantic Meridional Overturning Circulation on the Northern Hemisphere Surface Temperature Response to Radiative Forcing

2018 ◽  
Vol 31 (22) ◽  
pp. 9207-9224 ◽  
Author(s):  
Elizabeth A. Maroon ◽  
Jennifer E. Kay ◽  
Kristopher B. Karnauskas
Keyword(s):  
Surface Temperature ◽  
Greenhouse Gas ◽  
Internal Variability ◽  
Atlantic Meridional Overturning Circulation ◽  
Forced Response ◽  
Meridional Overturning Circulation ◽  
Surface Warming ◽  
Ensemble Mean ◽  
Meridional Overturning ◽  
Global Surface

ABSTRACT Many modeling studies have shown that the Atlantic meridional overturning circulation (AMOC) will weaken under increased greenhouse gas forcing, but the influence of AMOC internal variability on climate change in the context of a large initial condition ensemble has received less attention. Here, the Community Earth System Model Large Ensemble (CESM LE) is used to separate the AMOC-forced response from AMOC internal variability, and then assess their joint influence on surface warming. Similar to other models, the CESM LE projects a weakening AMOC in response to increased greenhouse gas forcing caused by freshening and decreased buoyancy fluxes in the North Atlantic. Yet if this forced response is removed using the ensemble mean, there is a positive relationship between global surface warming and AMOC strength. In other words, when the AMOC strengthens relative to the ensemble mean (i.e., weakens less), global surface warming increases relative to the ensemble mean response. This unforced surface warming occurs in northern Eurasia and in the Nordic and Barents Seas near the sea ice edge. Comparison of CESM simulations with and without a dynamic ocean shows that the unforced surface warming in the Nordic and Barents Seas results from both ocean and atmospheric circulation variability. In contrast, this comparison suggests that AMOC-associated Eurasian warming results from atmospheric circulation variability alone. In sum, the AMOC-forced response and AMOC internal variability have distinct relationships with surface temperature. Forced AMOC weakening decreases with surface warming, while unforced AMOC strengthening leads to surface warming.

2014 Warmest Year in Modern Record: Climate Monitoring and Its Possible Cause

2016 ◽  
Vol 04 (02) ◽  
pp. 1650018
Author(s):  
Bing ZHOU ◽  
Yu NIE ◽  
Pengling WANG
Keyword(s):  
Climate Change ◽  
Surface Temperature ◽  
Climate Warming ◽  
Land Surface ◽  
Heat Content ◽  
Ocean Heat Content ◽  
Extreme Weather Events ◽  
Sea Ice Extent ◽  
Weather Events ◽  
Possible Cause

Global warming and increasing extreme weather events are two important facts under climate change. In 2014, the global average surface temperature surged to a new high, ranking as the Earth’s warmest year since 1850. Using the observational datasets of land surface temperature, sea-surface temperature (SST), ocean heat content, precipitation, sea ice extent, etc. from 1850 to 2014, this paper, from the perspective of climate change, examines the observational evidence in the warmest year by comprehensively analyzing the changing characteristics of the global surface temperature, ocean heat content as well as the surface temperature in key regions. Meanwhile, this paper analyzes the possible cause of the warmest year from the factors of human activities and the ocean forcing. Finally, based on these analyses, the authors point out some possible damage caused by climate warming and further present some necessary approaches to combating climate warming.

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