scholarly journals Modelling Aerosol Effects on Liquid Clouds in the Summertime Arctic

2021 ◽  
Author(s):  
Roya Ghahreman ◽  
Wanmin Gong ◽  
Stephen R. Beagley ◽  
Ayodeji Akingunola ◽  
Paul A. Makar ◽  
...  
Keyword(s):  
Aerosol Effects

scholarly journals IAP-AACM v1.0： Global to regional evaluation of the atmospheric chemistry model in CAS-ESM

2018 ◽  
Author(s):  
Ying Wei ◽  
Xueshun Chen ◽  
Huansheng Chen ◽  
Jie Li ◽  
Zifa Wang ◽  
...  
Keyword(s):  
East Asia ◽  
Spatial Variation ◽  
Atmospheric Chemistry ◽  
Comprehensive Evaluation ◽  
Correlation Coefficients ◽  
Full Description ◽  
Atmospheric Physics ◽  
Temporal And Spatial Variability ◽  
Fine Mode ◽  
Aerosol Effects

Abstract. In this study, a full description and comprehensive evaluation of a global-regional nested model, the Aerosol and Atmospheric Chemistry Model of the Institute of Atmospheric Physics (IAP-AACM), is presented for the first time. Not only the global budgets and distribution, but also a comparison of nested simulation over China against multi-datasets are investigated, benefiting from the access of air quality monitoring data in China since 2013 and the Model Inter-Comparison Study for Asia project. The model results and analysis can greatly help reduce uncertainties and understand model diversity in assessing global and regional aerosol effects, especially over East Asia and areas affected by East Asia. The 1-year simulation for 2014 shows that the IAP-AACM is within the range of other models, and well reproduces both spatial distribution and seasonal variation of trace gases and aerosols over major continents and oceans (mostly within the factor of two). The model nicely captures spatial variation for carbon monoxide except an underestimation over the ocean that also shown in other models, which suggests the need for more accurate emission rate of ocean source. For aerosols, the simulation of fine-mode particulate matter (PM2.5) matches observation well and it has a better simulating ability on primary aerosols than secondary aerosols. This calls for more investigation on aerosol chemistry. Furthermore, IAP-AACM shows the superiority of global model, compared with regional model, on performing regional transportation for the nested simulation over East Asia. For the city evaluation over China, the model reproduces variation of sulfur dioxide (SO2), nitrogen dioxide (NO2) and PM2.5 accurately in most cities, with correlation coefficients above 0.5. Compared to the global simulation, the nested simulation exhibits an improved ability to capture the high temporal and spatial variability over China. In particular, the correlation coefficients for PM2.5, SO2 and NO2 are raised by ~ 0.25, ~ 0.15 and ~ 0.2 respectively in the nested grid. The summary provides constructive information for the application of chemical transport models. In future, we recommend the model's ability to capture high spatial variation of PM2.5 is yet to be improved.

scholarly journals Estimate of the Cloud and Aerosol Effects on the Surface Radiative Flux Based on the Measurements and the Transfer Model Calculations

1999 ◽  
Vol 77 (5) ◽  
pp. 1007-1021 ◽  
Author(s):  
Yukari N. Takayabu ◽  
T. Ueno ◽  
T. Nakajima ◽  
I. Matsui ◽  
Y. Tsushima ◽  
...  
Keyword(s):  
Radiative Flux ◽  
Transfer Model ◽  
Model Calculations ◽  
Aerosol Effects

scholarly journals Aerosol Effects on Cloud Emissivity and Surface Longwave Heating in the Arctic

2002 ◽  
Vol 59 (3) ◽  
pp. 769-778 ◽  
Author(s):  
Timothy J. Garrett ◽  
Lawrence F. Radke ◽  
Peter V. Hobbs
Keyword(s):  
The Arctic ◽  
Aerosol Effects

Aerosol Effects on Temperature Forecast in the COSMO-Ru Model

2021 ◽  
pp. 29-39
Author(s):  
A. A. Poliukhov ◽  
◽  
D. V. Blinov ◽  
◽  
Keyword(s):  
Air Temperature ◽  
Numerical Experiments ◽  
Surface Air Temperature ◽  
European Part ◽  
Clear Sky ◽  
Temperature Forecast ◽  
European Part Of Russia ◽  
Simulated Surface ◽  
Aerosol Effects ◽  
Sky Conditions

Aerosol effects on the forecast of surface temperature, as well as temperature at the levels of 850 and 500 hPa over Europe and the European part of Russia are studied using various aerosol climatologies: Tanre, Tegen, and MACv2. The numerical experiments with the COSMO-Ru model are performed for the central months of the seasons (January, April, July, and October) in 2017. It is found that a change in the simulated surface air temperature over land can reach 1C when using Tegen and MACv2 data as compared to Tanre. At 850 and 500 hPa levels, the changes do not exceed 0.4C. At the same time, it is shown that a decrease in the root-mean-square error of 2-m air temperature forecast at individual stations reaches 0.5C when using Tegen and MACv2 data and 1C for clear-sky conditions in Moscow.

scholarly journals Sulfate geoengineering: a review of the factors controlling the needed injection of sulfur dioxide

2016 ◽  
Author(s):  
Daniele Visioni ◽  
Giovanni Pitari ◽  
Valentina Aquila
Keyword(s):  
Lower Stratosphere ◽  
Effective Means ◽  
Climate Engineering ◽  
Radiative Effects ◽  
Stratospheric Water Vapor ◽  
Long Wave ◽  
Engineering Technique ◽  
Aerosol Effects ◽  
Induced Changes ◽  
Fine Tune

Abstract. Sulfate geoengineering has been proposed as an affordable and climate-effective means for temporarily offset the warming produced by the increase of well mixed greenhouse gases (WMGHG). This climate engineering technique has been planned for a timeframe of a few decades needed to implement global inter-governmental measures needed to achieve stabilization of the atmospheric content of WMGHGs (CO2 in particular). The direct radiative effects of sulfur injection in the tropical lower stratosphere can be summarized as increasing shortwave scattering with consequent tropospheric cooling and increasing long- wave absorption with stratospheric warming. Indirect radiative effects are related to induced changes in the ozone distribution, stratospheric water vapor abundance, formation and size of upper tropospheric cirrus ice particles and lifetime of longlived species, namely CH4 in connection with OH changes through several photochemical mechanisms. A direct comparison of the net effects of WMGHG increase with direct and indirect effects of sulfate geoengineering may help fine-tune the best amount of sulfate to be injected in an eventual realization of the experiment. However, we need to take into account large uncertainties in the estimate of some of these aerosol effects, such as cirrus ice particle size modifications.

Aerosol effects on the timing of warm rain processes

2015 ◽  
Vol 42 (11) ◽  
pp. 4590-4598 ◽  
Author(s):  
Guy Dagan ◽  
Ilan Koren ◽  
Orit Altaratz
Keyword(s):  
Warm Rain ◽  
Aerosol Effects

scholarly journals How do changes in warm-phase microphysics affect deep convective clouds?

2017 ◽  
Vol 17 (15) ◽  
pp. 9585-9598 ◽  
Author(s):  
Qian Chen ◽  
Ilan Koren ◽  
Orit Altaratz ◽  
Reuven H. Heiblum ◽  
Guy Dagan ◽  
...  
Keyword(s):  
Rain Rate ◽  
Convective Cloud ◽  
Cloud Fraction ◽  
Marshall Islands ◽  
Cloud System ◽  
Main Question ◽  
Convective Clouds ◽  
Deep Convective Clouds ◽  
Aerosol Effects ◽  
Deep Convective Cloud

Abstract. Understanding aerosol effects on deep convective clouds and the derived effects on the radiation budget and rain patterns can largely contribute to estimations of climate uncertainties. The challenge is difficult in part because key microphysical processes in the mixed and cold phases are still not well understood. For deep convective clouds with a warm base, understanding aerosol effects on the warm processes is extremely important as they set the initial and boundary conditions for the cold processes. Therefore, the focus of this study is the warm phase, which can be better resolved. The main question is: How do aerosol-derived changes in the warm phase affect the properties of deep convective cloud systems? To explore this question, we used a weather research and forecasting (WRF) model with spectral bin microphysics to simulate a deep convective cloud system over the Marshall Islands during the Kwajalein Experiment (KWAJEX). The model results were validated against observations, showing similarities in the vertical profile of radar reflectivity and the surface rain rate. Simulations with larger aerosol loading resulted in a larger total cloud mass, a larger cloud fraction in the upper levels, and a larger frequency of strong updrafts and rain rates. Enlarged mass both below and above the zero temperature level (ZTL) contributed to the increase in cloud total mass (water and ice) in the polluted runs. Increased condensation efficiency of cloud droplets governed the gain in mass below the ZTL, while both enhanced condensational and depositional growth led to increased mass above it. The enhanced mass loading above the ZTL acted to reduce the cloud buoyancy, while the thermal buoyancy (driven by the enhanced latent heat release) increased in the polluted runs. The overall effect showed an increased upward transport (across the ZTL) of liquid water driven by both larger updrafts and larger droplet mobility. These aerosol effects were reflected in the larger ratio between the masses located above and below the ZTL in the polluted runs. When comparing the net mass flux crossing the ZTL in the clean and polluted runs, the difference was small. However, when comparing the upward and downward fluxes separately, the increase in aerosol concentration was seen to dramatically increase the fluxes in both directions, indicating the aerosol amplification effect of the convection and the affected cloud system properties, such as cloud fraction and rain rate.

scholarly journals Global impact of smoke aerosols from landscape fires on climate and the Hadley circulation

2013 ◽  
Vol 13 (10) ◽  
pp. 5227-5241 ◽  
Author(s):  
M. G. Tosca ◽  
J. T. Randerson ◽  
C. S. Zender
Keyword(s):  
Hadley Circulation ◽  
Surface Radiation ◽  
Climate Response ◽  
Fire Emissions ◽  
Aerosol Forcing ◽  
Surface Temperatures ◽  
Community Atmosphere Model ◽  
Tropospheric Heating ◽  
Aerosol Effects ◽  
Global Precipitation

Abstract. Each year landscape fires across the globe emit black and organic carbon smoke particles that can last in the atmosphere for days to weeks. We characterized the climate response to these aerosols using an Earth system model. We used remote sensing observations of aerosol optical depth (AOD) and simulations from the Community Atmosphere Model, version 5 (CAM5) to optimize satellite-derived smoke emissions for high biomass burning regions. Subsequent global simulations using the adjusted fire emissions produced AODs that were in closer agreement with surface and space-based measurements. We then used CAM5, which included radiative aerosol effects, to evaluate the climate response to the fire-aerosol forcing. We conducted two 52 yr simulations, one with four sets of monthly cycling 1997–2009 fire emissions and one without. Fire emissions increased global mean annual AOD by 10% (+0.02) and decreased net all-sky surface radiation by 1% (1.3 W m−2). Elevated AODs reduced global surface temperatures by 0.13 ± 0.01 °C. Though global precipitation declined only slightly, patterns of precipitation changed, with large reductions near the Equator offset by smaller increases north and south of the intertropical convergence zone (ITCZ). A combination of increased tropospheric heating and reduced surface temperatures increased equatorial subsidence and weakened the Hadley circulation. As a consequence, precipitation decreased over tropical forests in South America, Africa and equatorial Asia. These results are consistent with the observed correlation between global temperatures and the strength of the Hadley circulation and studies linking tropospheric heating from black carbon aerosols with tropical expansion.

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