scholarly journals Simulation of aerosol distributions and radiative forcing for INDOEX: Regional climate impacts

2002 ◽  
Vol 107 (D19) ◽  
Author(s):  
William D. Collins
Keyword(s):  
Radiative Forcing ◽  
Regional Climate ◽  
Climate Impacts

scholarly journals Emission metrics for quantifying regional climate impacts of aviation

2017 ◽  
Vol 8 (3) ◽  
pp. 547-563 ◽  
Author(s):  
Marianne T. Lund ◽  
Borgar Aamaas ◽  
Terje Berntsen ◽  
Lisa Bock ◽  
Ulrike Burkhardt ◽  
...  
Keyword(s):  
North America ◽  
Temperature Change ◽  
Radiative Forcing ◽  
Large Scale ◽  
Regional Climate ◽  
Temperature Response ◽  
Climate Impacts ◽  
Source Regions ◽  
Latitudinal Patterns ◽  
Regional Temperature

Abstract. This study examines the impacts of emissions from aviation in six source regions on global and regional temperatures. We consider the NOx-induced impacts on ozone and methane, aerosols and contrail-cirrus formation and calculate the global and regional emission metrics global warming potential (GWP), global temperature change potential (GTP) and absolute regional temperature change potential (ARTP). The GWPs and GTPs vary by a factor of 2–4 between source regions. We find the highest aviation aerosol metric values for South Asian emissions, while contrail-cirrus metrics are higher for Europe and North America, where contrail formation is prevalent, and South America plus Africa, where the optical depth is large once contrails form. The ARTP illustrate important differences in the latitudinal patterns of radiative forcing (RF) and temperature response: the temperature response in a given latitude band can be considerably stronger than suggested by the RF in that band, also emphasizing the importance of large-scale circulation impacts. To place our metrics in context, we quantify temperature change in four broad latitude bands following 1 year of emissions from present-day aviation, including CO2. Aviation over North America and Europe causes the largest net warming impact in all latitude bands, reflecting the higher air traffic activity in these regions. Contrail cirrus gives the largest warming contribution in the short term, but remain important at about 15 % of the CO2 impact in several regions even after 100 years. Our results also illustrate both the short- and long-term impacts of CO2: while CO2 becomes dominant on longer timescales, it also gives a notable warming contribution already 20 years after the emission. Our emission metrics can be further used to estimate regional temperature change under alternative aviation emission scenarios. A first evaluation of the ARTP in the context of aviation suggests that further work to account for vertical sensitivities in the relationship between RF and temperature response would be valuable for further use of the concept.

scholarly journals Emission metrics for quantifying regional climate impacts of aviation

2017 ◽  
Author(s):  
Marianne T. Lund ◽  
Borgar Aamaas ◽  
Terje Berntsen ◽  
Lisa Bock ◽  
Ulrike Burkhardt ◽  
...  
Keyword(s):  
North America ◽  
Temperature Change ◽  
Radiative Forcing ◽  
Large Scale ◽  
Regional Climate ◽  
Temperature Response ◽  
Climate Impacts ◽  
Pulse Emission ◽  
Source Regions ◽  
Regional Temperature

Abstract. This study examines the impacts of emissions from aviation in six source regions on global and regional temperature. We consider the NOx-induced impacts on ozone and methane, aerosols and contrail-cirrus formation, and calculate the global and regional climate metrics Global Warming Potential (GWP), Global Temperature change Potential (GTP) and Absolute Regional Temperature change Potential (ARTP). GWPs and GTPs vary by a factor 2–4 between source regions. We find the highest aviation aerosol metric values for South Asian emissions, while contrail-cirrus metrics are higher for Europe and North America, where contrail formation is prevalent, and South America plus Africa, where the optical depth is large once contrails form. The ARTP illustrate important differences in the latitudinal patterns of radiative forcing (RF) and temperature response: The temperature response in a given latitude band can be considerably stronger than suggested by the RF in that band, also emphasizing the importance of large-scale circulation impacts. To place our metrics in context, we quantify the temperature response in the four broad latitude bands following a one-year pulse emission from present-day aviation, including CO2. Aviation over North America and Europe cause the largest net warming impact in all latitude bands, reflecting the higher air traffic activity here. For all regions, the largest single warming contribution is from contrail-cirrus 20 years after the emissions, while CO2 becomes dominant at 100 years, although contrail-cirrus remain important in several regions also on this time scale. Our emission metrics can be further used to estimate regional temperature impact under alternative aviation emission scenarios. A first evaluation of the ARTP in the context of aviation suggests that further work to account for vertical sensitivities in the relationship between RF and temperature response would be valuable for further use of the concept.

scholarly journals A two-stage Bayesian multi-model framework for improving multidimensional drought risk projections over China

2020 ◽  
Author(s):  
Boen Zhang ◽  
Shuo Wang ◽  
Jinxin Zhu
Keyword(s):  
Radiative Forcing ◽  
Potential Evapotranspiration ◽  
Regional Climate ◽  
Bayesian Framework ◽  
Climate Impacts ◽  
Drought Risk ◽  
Emission Scenarios ◽  
Model Framework ◽  
Drought Duration ◽  
Copula Approach

Abstract. Understanding future drought risk is a prerequisite for developing climate change adaptation strategies and for enhancing disaster resilience. In this study, we develop multi-model probabilistic projections of multidimensional drought risks under two representative emission scenarios (RCP4.5 and RCP8.5) through a copula-based Bayesian framework. An ensemble of five regional climate simulations, including four from the CORDEX East Asia experiment and one from the Providing REgional Climate Impacts for Studies (PRECIS) simulation, is used to project future changes in hydroclimatic regimes over China. A new Bayesian copula approach is introduced to uncover underlying interactions of drought characteristics and associated uncertainties over 10 climate divisions of China. The proposed Bayesian framework explicitly addresses the cascade of uncertainty in high-resolution projections of multidimensional drought risks. Our findings reveal that precipitation and potential evapotranspiration (PET) are projected to increase for most areas of China, while increasing radiative forcing is expected to amplify the increase in PET but does not cause significant changes in the precipitation projection. In addition, the drought duration and severity are projected to substantially increase for most areas of China. The estimated drought risks in China are expected to become more than double under both emission scenarios. The extreme droughts are projected to intensify in terms of frequency and associated risks as the radiative forcing increases.

scholarly journals Incorrect Asian aerosols affecting the attribution and projection of regional climate change in CMIP6 models

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Zhili Wang ◽  
Lei Lin ◽  
Yangyang Xu ◽  
Huizheng Che ◽  
Xiaoye Zhang ◽  
...  
Keyword(s):  
Climate Change ◽  
Radiative Forcing ◽  
Impact Analysis ◽  
Climate Model ◽  
Regional Climate ◽  
Eastern China ◽  
Coupled Model ◽  
Regional Climate Change ◽  
Anthropogenic Aerosol ◽  
Wide Range

AbstractAnthropogenic aerosol (AA) forcing has been shown as a critical driver of climate change over Asia since the mid-20th century. Here we show that almost all Coupled Model Intercomparison Project Phase 6 (CMIP6) models fail to capture the observed dipole pattern of aerosol optical depth (AOD) trends over Asia during 2006–2014, last decade of CMIP6 historical simulation, due to an opposite trend over eastern China compared with observations. The incorrect AOD trend over China is attributed to problematic AA emissions adopted by CMIP6. There are obvious differences in simulated regional aerosol radiative forcing and temperature responses over Asia when using two different emissions inventories (one adopted by CMIP6; the other from Peking university, a more trustworthy inventory) to driving a global aerosol-climate model separately. We further show that some widely adopted CMIP6 pathways (after 2015) also significantly underestimate the more recent decline in AA emissions over China. These flaws may bring about errors to the CMIP6-based regional climate attribution over Asia for the last two decades and projection for the next few decades, previously anticipated to inform a wide range of impact analysis.

scholarly journals Projected Changes in Extreme Temperature and Precipitation Indices Over CORDEX-MENA Domain

Atmosphere ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 622
Author(s):  
Tugba Ozturk ◽  
F. Sibel Saygili-Araci ◽  
M. Levent Kurnaz
Keyword(s):  
Regional Climate Model ◽  
Radiative Forcing ◽  
Climate Model ◽  
Global Climate Model ◽  
Regional Climate ◽  
Climate Extreme ◽  
Pronounced Increase ◽  
Temperature And Precipitation ◽  
Projected Changes ◽  
Extreme Indices

In this study, projected changes in climate extreme indices defined by the Expert Team on Climate Change Detection and Indices were investigated over Middle East and North Africa. Changes in the daily maximum and minimum temperature- and precipitation- based extreme indices were analyzed for the end of the 21st century compared to the reference period 1971–2000 using regional climate model simulations. Regional climate model, RegCM4.4 was used to downscale two different global climate model outputs to 50 km resolution under RCP4.5 and RCP8.5 scenarios. Results generally indicate an intensification of temperature- and precipitation- based extreme indices with increasing radiative forcing. In particular, an increase in annual minimum of daily minimum temperatures is more pronounced over the northern part of Mediterranean Basin and tropics. High increase in warm nights and warm spell duration all over the region with a pronounced increase in tropics are projected for the period of 2071–2100 together with decrease or no change in cold extremes. According to the results, a decrease in total wet-day precipitation and increase in dry spells are expected for the end of the century.

The influence of global climate changes on Western Siberia climate in the first half of XXI century

2018 ◽  
Author(s):  
А.А. Лагутин ◽  
Н.В. Волков ◽  
Е.Ю. Мордвин
Keyword(s):  
Radiative Forcing ◽  
Climate Changes ◽  
Western Siberia ◽  
Climate Model ◽  
Global Climate ◽  
Regional Climate ◽  
First Century ◽  
Global Climate Changes ◽  
Rcp 8.5

Представлены результаты исследований влияния глобальных климатических изменений системы Земля на климат Западной Сибири. Для установления зон региона, в которых к середине XXI в. прогнозируются изменения, использовались модельные данные региональной климатической модели RegCM4 и принятые в этом классе задач стандартизованные евклидовы расстояния между характеристиками климата для двух состояний климатической системы — современного и будущего. Установлены зоны Западной Сибири, в которых в рамках сценариев RCP 4.5 и RCP 8.5 возможной эволюции глобальной системы к 2050 г. прогнозируются изменения климата. Purpose. An analysis of the influence of a global climate changes on the climate of Western Siberia, determination of zones of the region where changes are expected in the middle of the twenty-first century. Methodology. Results obtained using the model data of the regional climate model RegCM4 and the standardized Euclidean distances between climate characteristics. Findings, originality. Simulations of the climate characteristics for the two states of the climate system — contemporary and future — have been carried out. The zones of Western Siberia region, in which climate change is expected in the framework of RCP 4.5 and RCP 8.5 radiative forcing scenarios by the 2050, have been determined.

scholarly journals Atmospheric circulation and hydroclimate impacts of alternative warming scenarios for the Eocene

2017 ◽  
Vol 13 (8) ◽  
pp. 1037-1048 ◽  
Author(s):  
Henrik Carlson ◽  
Rodrigo Caballero
Keyword(s):  
Surface Temperature ◽  
Radiative Forcing ◽  
Climate Models ◽  
Climate Model ◽  
Regional Climate ◽  
Warm Season ◽  
Cloud Albedo ◽  
Cloud Properties ◽  
Atmospheric Co2 Concentrations ◽  
Global Mean

Abstract. Recent work in modelling the warm climates of the early Eocene shows that it is possible to obtain a reasonable global match between model surface temperature and proxy reconstructions, but only by using extremely high atmospheric CO2 concentrations or more modest CO2 levels complemented by a reduction in global cloud albedo. Understanding the mix of radiative forcing that gave rise to Eocene warmth has important implications for constraining Earth's climate sensitivity, but progress in this direction is hampered by the lack of direct proxy constraints on cloud properties. Here, we explore the potential for distinguishing among different radiative forcing scenarios via their impact on regional climate changes. We do this by comparing climate model simulations of two end-member scenarios: one in which the climate is warmed entirely by CO2 (which we refer to as the greenhouse gas (GHG) scenario) and another in which it is warmed entirely by reduced cloud albedo (which we refer to as the low CO2–thin clouds or LCTC scenario) . The two simulations have an almost identical global-mean surface temperature and equator-to-pole temperature difference, but the LCTC scenario has  ∼  11 % greater global-mean precipitation than the GHG scenario. The LCTC scenario also has cooler midlatitude continents and warmer oceans than the GHG scenario and a tropical climate which is significantly more El Niño-like. Extremely high warm-season temperatures in the subtropics are mitigated in the LCTC scenario, while cool-season temperatures are lower at all latitudes. These changes appear large enough to motivate further, more detailed study using other climate models and a more realistic set of modelling assumptions.

Regional climate impacts of the Southern Annular Mode

2006 ◽  
Vol 33 (23) ◽  
Author(s):  
N. P. Gillett ◽  
T. D. Kell ◽  
P. D. Jones
Keyword(s):  
Regional Climate ◽  
Southern Annular Mode ◽  
Climate Impacts ◽  
Annular Mode

scholarly journals Dust emission size distribution impact on aerosol budget and radiative forcing over the Mediterranean region: a regional climate model approach

2012 ◽  
Vol 12 (21) ◽  
pp. 10545-10567 ◽  
Author(s):  
P. Nabat ◽  
F. Solmon ◽  
M. Mallet ◽  
J. F. Kok ◽  
S. Somot
Keyword(s):  
Size Distribution ◽  
Radiative Forcing ◽  
Mediterranean Basin ◽  
Climate Model ◽  
Regional Climate ◽  
Dust Emission ◽  
Dust Deposition ◽  
The Mediterranean ◽  
Dust Distribution ◽  
The Mediterranean Basin

Abstract. The present study investigates the dust emission and load over the Mediterranean basin using the coupled chemistry–aerosol–regional climate model RegCM-4. The first step of this work focuses on dust particle emission size distribution modeling. We compare a parameterization in which the emission is based on the individual kinetic energy of the aggregates striking the surface to a recent parameterization based on an analogy with the fragmentation of brittle materials. The main difference between the two dust schemes concerns the mass proportion of fine aerosol that is reduced in the case of the new dust parameterization, with consequences for optical properties. At the episodic scale, comparisons between RegCM-4 simulations, satellite and ground-based data show a clear improvement using the new dust distribution in terms of aerosol optical depth (AOD) values and geographic gradients. These results are confirmed at the seasonal scale for the investigated year 2008. This change of dust distribution has sensitive impacts on the simulated regional dust budget, notably dry dust deposition and the regional direct aerosol radiative forcing over the Mediterranean basin. In particular, we find that the new size distribution produces a higher dust deposition flux, and smaller top of atmosphere (TOA) dust radiative cooling. A multi-annual simulation is finally carried out using the new dust distribution over the period 2000–2009. The average SW radiative forcing over the Mediterranean Sea reaches −13.6 W m−2 at the surface, and −5.5 W m−2 at TOA. The LW radiative forcing is positive over the basin: 1.7 W m−2 on average over the Mediterranean Sea at the surface, and 0.6 W m−2 at TOA.

scholarly journals Ocean-atmosphere interactions modulate irrigation's climate impacts

2016 ◽  
Author(s):  
Nir Y. Krakauer ◽  
Michael J. Puma ◽  
Benjamin I. Cook ◽  
Pierre Gentine ◽  
Larissa Nazarenko
Keyword(s):  
Water Cycle ◽  
Regional Climate ◽  
Mean Amplitude ◽  
Climate Impacts ◽  
Irrigated Agriculture ◽  
Ocean Atmosphere ◽  
Ocean Atmosphere Interaction ◽  
Atmosphere Interaction ◽  
The Tropics ◽  
Global Mean

Abstract. Numerous studies have focused on the local and regional climate effects of irrigated agriculture and other land cover and land use change (LCLUC) phenomena, but there are few studies on the role of ocean-atmosphere interaction in modulating irrigation climate impacts. Here, we compare simulations of the equilibrium effect of contemporary irrigation geographic extent and intensity on climate with and without interactive sea surface temperatures. We find that ocean-atmosphere interaction does impact the magnitude of global-mean and spatially varying climate impacts, greatly increasing their global reach. The interaction amplifies irrigation-driven standing wave patterns in the tropics and midlatitudes in our simulations, approximately doubling the global mean amplitude of surface temperature changes due to irrigation. Subject to confirmation with other models, these findings imply that LCLUC is an important contributor to climate change even in remote areas such as the Southern Ocean. Attribution studies should include interactive oceans and need to consider LCLUC, including irrigation, as a truly global forcing that affects climate and the water cycle over ocean as well as land areas.

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