scholarly journals The Arctic Temperature Response to Global and Regional Anthropogenic Sulfate Aerosols

2021 ◽  
Vol 9 ◽  
Author(s):  
Acharya Asutosh ◽  
Suvarna Fadnavis ◽  
M. Nuncio ◽  
Rolf Müller ◽  
Sarat C. Tripathy
Keyword(s):  
Radiative Forcing ◽  
Dominant Role ◽  
Winter Season ◽  
Temperature Response ◽  
Summer Season ◽  
The Arctic ◽  
Sulfate Aerosols ◽  
Surface Cooling ◽  
Cloud Radiative Forcing ◽  
High Level

The mechanisms behind Arctic warming and associated climate changes are difficult to discern. Also, the complex local processes and feedbacks like aerosol-cloud-climate interactions are yet to be quantified. Here, using the Community Earth System Model (CAM5) experiments, with emission enhancement of anthropogenic sulfate 1) five-fold globally, 2) ten-times over Asia, and 3) ten-times over Europe we show that regional emissions of sulfate aerosols alter seasonal warming over the Arctic, i.e., colder summer and warmer winter. European emissions play a dominant role in cooling during the summer season (0.7 K), while Asian emissions dominate the warming during the winter season (maximum ∼0.6 K) in the Arctic surface. The cooling/warming is associated with a negative/positive cloud radiative forcing. During the summer season increase in low–mid level clouds, induced by sulfate emissions, favours the solar dimming effect that reduces the downwelling radiation to the surface and thus leads to surface cooling. Warmer winters are associated with enhanced high-level clouds that induce a positive radiative forcing at the top of the atmosphere. This study points to the importance of international strategies being implemented to control sulfate emissions to combat air pollution. Such strategies will also affect the Arctic cooling/warming associated with a cloud radiative forcing caused by sulfate emission change.

scholarly journals Regional temperature change potentials for short-lived climate forcers based on radiative forcing from multiple models

2017 ◽  
Vol 17 (17) ◽  
pp. 10795-10809 ◽  
Author(s):  
Borgar Aamaas ◽  
Terje K. Berntsen ◽  
Jan S. Fuglestvedt ◽  
Keith P. Shine ◽  
William J. Collins
Keyword(s):  
East Asia ◽  
Temperature Change ◽  
Northern Hemisphere ◽  
Radiative Forcing ◽  
Atmospheric Transport ◽  
Winter Season ◽  
Temperature Response ◽  
The Arctic ◽  
Regional Temperature ◽  
Hemisphere Winter

Abstract. We calculate the absolute regional temperature change potential (ARTP) of various short-lived climate forcers (SLCFs) based on detailed radiative forcing (RF) calculations from four different models. The temperature response has been estimated for four latitude bands (90–28° S, 28° S–28° N, 28–60° N, and 60–90° N). The regional pattern in climate response not only depends on the relationship between RF and surface temperature, but also on where and when emissions occurred and atmospheric transport, chemistry, interaction with clouds, and deposition. We present four emissions cases covering Europe, East Asia, the global shipping sector, and the entire globe. Our study is the first to estimate ARTP values for emissions during Northern Hemisphere summer (May–October) and winter season (November–April). The species studied are aerosols and aerosol precursors (black carbon, organic carbon, SO2, NH3), ozone precursors (NOx, CO, volatile organic compound), and methane (CH4). For the response to BC in the Arctic, we take into account the vertical structure of the RF in the atmosphere, and an enhanced climate efficacy for BC deposition on snow. Of all SLCFs, BC is the most sensitive to where and when the emissions occur, as well as giving the largest difference in response between the latitude bands. The temperature response in the Arctic per unit BC emission is almost four times larger and more than two times larger than the global average for Northern Hemisphere winter emissions for Europe and East Asia, respectively. The latitudinal breakdown likely gives a better estimate of the global temperature response as it accounts for varying efficacies with latitude. An annual pulse of non-methane SLCF emissions globally (representative of 2008) lead to a global cooling. In contrast, winter emissions in Europe and East Asia give a net warming in the Arctic due to significant warming from BC deposition on snow.

scholarly journals Regional temperature change potentials for short lived climate forcers from multiple models

2017 ◽  
Author(s):  
Borgar Aamaas ◽  
Terje K. Berntsen ◽  
Jan S. Fuglestvedt ◽  
Keith P. Shine ◽  
William J. Collins
Keyword(s):  
East Asia ◽  
Temperature Change ◽  
Northern Hemisphere ◽  
Radiative Forcing ◽  
Atmospheric Transport ◽  
Winter Season ◽  
Temperature Response ◽  
The Arctic ◽  
Regional Temperature ◽  
Hemisphere Winter

Abstract. We calculate the absolute regional temperature change potential (ARTP) of various short lived climate forcers (SLCFs) based on detailed radiative forcing (RF) calculations from four different models. The temperature response has been estimated for four latitude bands (90–28° S, 28° S–28° N, 28–60° N, and 60–90° N). The regional pattern in climate response not only depends on the relationship between RF and surface temperature, but also on where and when emissions occurred and atmospheric transport, chemistry, interaction with clouds, and deposition. We present four emissions cases covering Europe, East Asia, the global shipping sector, and the globe. Our study is the first to estimate ARTP values for emissions during Northern Hemisphere summer (May–October) and winter season (November–April). The species studied are aerosols and aerosol precursors (black carbon (BC), organic carbon (OC), SO2, NH3), ozone precursors (NOx, CO, volatile organic compound (VOC)), and methane (CH4). For the response to BC in the Arctic, we take into account the vertical structure of the RF in the atmosphere, and an enhanced climate efficacy for BC deposition on snow. Of all SLCFs, BC is the most sensitive to where and when the emissions occur, as well as giving the largest difference in response between the latitude bands. The temperature response in the Arctic is almost 4 times larger and more than 2 times larger than the global average for Northern Hemisphere winter emissions for Europe and East Asia, respectively. The latitudinal breakdown gives likely a better estimate of the global temperature response as it accounts for varying efficacies with latitude. An annual pulse of non-methane SLCFs emissions globally (representative of 2008) leads to a global cooling. Whereas, winter emissions in Europe and East Asia give a net warming in the Arctic due to significant warming from BC deposition on snow.

scholarly journals Sensitivity of Arctic sulfate aerosol and clouds to changes in future surface seawater dimethylsulfide concentrations

2019 ◽  
Vol 19 (9) ◽  
pp. 6419-6435 ◽  
Author(s):  
Rashed Mahmood ◽  
Knut von Salzen ◽  
Ann-Lise Norman ◽  
Martí Galí ◽  
Maurice Levasseur
Keyword(s):  
Sea Ice ◽  
Radiative Forcing ◽  
Arctic Region ◽  
Sulfate Aerosol ◽  
The Arctic ◽  
Surface Seawater ◽  
Cloud Radiative Forcing ◽  
Future Global Warming ◽  
Arctic Surface ◽  
The Arctic Region

Abstract. Dimethylsulfide (DMS), outgassed from ocean waters, plays an important role in the climate system, as it oxidizes to methane sulfonic acid (MSA) and sulfur dioxide (SO2), which can lead to the formation of sulfate aerosol. Newly formed sulfate aerosol resulting from DMS oxidation may grow by condensation of gases, in-cloud oxidation, and coagulation to sizes where they may act as cloud condensation nuclei (CCN) and influence cloud properties. Under future global warming conditions, sea ice in the Arctic region is expected to decline significantly, which may lead to increased emissions of DMS from the open ocean and changes in cloud regimes. In this study we evaluate impacts of DMS on Arctic sulfate aerosol budget, changes in cloud droplet number concentration (CDNC), and cloud radiative forcing in the Arctic region under current and future sea ice conditions using an atmospheric global climate model. Given that future DMS concentrations are highly uncertain, several simulations with different surface seawater DMS concentrations and spatial distributions in the Arctic were performed in order to determine the sensitivity of sulfate aerosol budgets, CDNC, and cloud radiative forcing to Arctic surface seawater DMS concentrations. For any given amount and distribution of Arctic surface seawater DMS, similar amounts of sulfate are produced by oxidation of DMS in 2000 and 2050 despite large increases in DMS emission in the latter period due to sea ice retreat in the simulations. This relatively low sensitivity of sulfate burden is related to enhanced sulfate wet removal by precipitation in 2050. However simulated aerosol nucleation rates are higher in 2050, which results in an overall increase in CDNC and substantially more negative cloud radiative forcing. Thus potential future reductions in sea ice extent may cause cloud albedos to increase, resulting in a negative climate feedback on radiative forcing in the Arctic associated with ocean DMS emissions.

scholarly journals Infrared measurements in the Arctic using two Atmospheric Emitted Radiance Interferometers

2012 ◽  
Vol 5 (2) ◽  
pp. 329-344 ◽  
Author(s):  
Z. Mariani ◽  
K. Strong ◽  
M. Wolff ◽  
P. Rowe ◽  
V. Walden ◽  
...  
Keyword(s):  
Radiative Forcing ◽  
Atmospheric Temperature ◽  
The Arctic ◽  
Radiative Transfer Model ◽  
Spectral Radiance ◽  
Transfer Model ◽  
Surface Cooling ◽  
Radiative Balance ◽  
Infrared Measurements ◽  
The University

Abstract. The Extended-range Atmospheric Emitted Radiance Interferometer (E-AERI) is a moderate resolution (1 cm−1) Fourier transform infrared spectrometer for measuring the absolute downwelling infrared spectral radiance from the atmosphere between 400 and 3000 cm−1. The extended spectral range of the instrument permits monitoring of the 400–550 cm−1 (20–25 μm) region, where most of the infrared surface cooling currently occurs in the dry air of the Arctic. Spectra from the E-AERI have the potential to provide information about radiative balance, trace gases, and cloud properties in the Canadian high Arctic. Calibration, performance evaluation, and certification of the E-AERI were performed at the University of Wisconsin Space Science and Engineering Centre from September to October 2008. The instrument was then installed at the Polar Environment Atmospheric Research Laboratory (PEARL) Ridge Lab (610 m altitude) at Eureka, Nunavut, in October 2008, where it acquired one year of data. Measurements are taken every seven minutes year-round, including polar night when the solar-viewing spectrometers at PEARL are not operated. A similar instrument, the University of Idaho's Polar AERI (P-AERI), was installed at the Zero-altitude PEARL Auxiliary Laboratory (0PAL), 15 km away from the PEARL Ridge Lab, from March 2006 to June 2009. During the period of overlap, these two instruments provided calibrated radiance measurements from two altitudes. A fast line-by-line radiative transfer model is used to simulate the downwelling radiance at both altitudes; the largest differences (simulation-measurement) occur in spectral regions strongly influenced by atmospheric temperature and/or water vapour. The two AERI instruments at close proximity but located at two different altitudes are well-suited for investigating cloud forcing. As an example, it is shown that a thin, low ice cloud resulted in a 6% increase in irradiance. The presence of clouds creates a large surface radiative forcing in the Arctic, particularly in the 750–1200 cm−1 region where the downwelling radiance is several times greater than clear-sky radiances, which is significantly larger than in other more humid regions.

scholarly journals Infrared emission measurements in the Arctic using a new extended-range AERI

2011 ◽  
Vol 4 (5) ◽  
pp. 6411-6448 ◽  
Author(s):  
Z. Mariani ◽  
K. Strong ◽  
M. Wolff ◽  
P. Rowe ◽  
V. Walden ◽  
...  
Keyword(s):  
Radiative Forcing ◽  
The Arctic ◽  
Radiative Transfer Model ◽  
Spectral Radiance ◽  
Transfer Model ◽  
Surface Cooling ◽  
Radiative Balance ◽  
Ice Cloud ◽  
Extended Range ◽  
The University

Abstract. The Extended-range Atmospheric Emitted Radiance Interferometer (E-AERI) is a moderate resolution (1 cm−1) Fourier transform infrared spectrometer for measuring the absolute downwelling infrared spectral radiance from the atmosphere between 400 and 3000 cm−1. The extended spectral range of the instrument permits monitoring of the 400–550 cm−1 (20–25 μm) region, where most of the infrared surface cooling currently occurs in the dry air of the Arctic. Spectra from the E-AERI have the potential to provide information about radiative balance, trace gases, and cloud properties in the Canadian high Arctic. Calibration, performance evaluation, and certification of the E-AERI were performed at the University of Wisconsin Space Science and Engineering Centre from September to October 2008. The instrument was then installed at the Polar Environment Atmospheric Research Laboratory (PEARL) Ridge Lab at Eureka, Nunavut, in October 2008, where it acquired one year of data. Measurements are taken every seven minutes year-round, including polar night when the solar-viewing spectrometers at PEARL are not operated. A similar instrument, the University of Idaho's Polar AERI (P-AERI), was installed at the Zero-altitude PEARL Auxiliary Laboratory (0PAL) from March 2006 to June 2009. During the period of overlap, these two instruments provided calibrated radiance measurements from two altitudes. A fast line-by-line radiative transfer model is used to simulate the downwelling radiance at both altitudes; the largest differences (simulation-measurement) occur in spectral regions strongly influenced by atmospheric temperature and/or water vapour. The presence of two AERI instruments at close proximity but two different altitudes allowed for an investigation of the surface radiative forcing by a thin, low ice cloud; the ice cloud resulted in a 6% increase in irradiance. The presence of clouds creates a large surface radiative forcing in the Arctic, particularly in the 750–1200 cm−1 region where the downwelling radiance is several times greater than clear-sky radiances, which is significantly larger than in other more humid regions.

scholarly journals Radiative energy budget and cloud radiative forcing in the daytime marginal sea ice zone during Arctic spring and summer

2021 ◽  
Author(s):  
Johannes Stapf ◽  
André Ehrlich ◽  
Christof Lüpkes ◽  
Manfred Wendisch
Keyword(s):  
Boundary Layer ◽  
Sea Ice ◽  
Energy Budget ◽  
Radiative Forcing ◽  
The Arctic ◽  
Radiative Energy ◽  
Cloud Radiative Forcing ◽  
Airborne Measurements ◽  
Marginal Sea ◽  
The Impact

Abstract. Airborne measurements of the surface radiative energy budget (REB) collected in the area of the marginal sea ice zone (MIZ) close to Svalbard (Norway) during two campaigns conducted in early spring and and early summer are presented. From the data, the cloud radiative forcing was derived. The analysis is focussed on the impact of changing atmospheric thermodynamic conditions on the REB and on the linkage of sea ice properties and cloud radiative forcing (CRF). The observed two-mode longwave net irradiance frequency distributions above sea ice are compared with measurements from previous studies. The transition of both states (cloudy and cloud-free) from winter towards summer and the associated broadening of the modes is discussed as a function of the seasonal thermodynamic profiles and the surface type. The influence of cold air outbreaks (CAO) and warm air intrusions on the REB is illustrated for several case studies, whereby the source and sink terms of REB in the evolving CAO boundary layer are quantified. Furthermore, the role of thermodynamic profiles and the vertical location of clouds during on-ice flow is illustrated. The sea ice concentration was identified as the main driver of the shortwave cooling by the clouds. The longwave warming of clouds, estimated to about 75 W m−2, seems to be representative for this region, as compared to other studies. Simplified radiative transfer simulations of the frequently observed low-level boundary layer clouds and average thermodynamic profiles represent the observed radiative quantities fairly well. The simulations illustrate the delicate interplay of surface and cloud properties that modify the REB and CRF, and the challenges in quantifying trends in the Arctic REB induced by potential changes of the cloud optical thickness.

scholarly journals The effect of aerosol on surface cloud radiative forcing in the Arctic

2005 ◽  
Vol 5 (5) ◽  
pp. 9039-9063 ◽  
Author(s):  
R.-M. Hu ◽  
J.-P. Blanchet ◽  
E. Girard
Keyword(s):  
Radiative Forcing ◽  
Climate Models ◽  
Climate Model ◽  
Regional Climate ◽  
High Surface ◽  
The Arctic ◽  
Cloud Radiative Forcing ◽  
Cloud Forcing ◽  
Aerosol Forcing ◽  
Albedo Effect

Abstract. Cloud radiative forcing is a very important concept to understand what kind of role the clouds play in climate change with thermal effect or albedo effect. In spite of that much progress has been achieved, the clouds are still poorly described in the climate models. Due to the complex aerosol-cloud-radiation interactions, high surface albedo of snow and ice cover, and without solar radiation in long period of the year, the Arctic strong warming caused by increasing greenhouse gases (as most GCMs suggested) has not been verified by the observations. In this study, we were dedicated to quantify the aerosol effect on the Arctic cloud radiative forcing by Northern Aerosol Regional Climate Model (NARCM). Major aerosol species such as Arctic haze sulphate, black carbon, sea salt, organics and dust have been included during our simulations. By inter-comparisons with the Atmospheric Radiation Measurement (ARM) data, we find surface cloud radiative forcing (SCRF) is −22 W/m2 for shortwave and 36 W/m2 for longwave. Total cloud forcing is 14 W/m2 with minimum of −35 W/m2 in early July. If aerosols are taken into account, the SCRF has been increased during winter while negative SCRF has been enhanced during summer. Our estimate of aerosol forcing is about −6 W/m2 in the Arctic.

scholarly journals Local and remote temperature response of regional SO<sub>2</sub> emissions

2018 ◽  
Author(s):  
Anna Lewinschal ◽  
Annica M. L. Ekman ◽  
Hans-Christen Hansson ◽  
Maria Sand ◽  
Terje K. Berntsen ◽  
...  
Keyword(s):  
East Asia ◽  
South Asia ◽  
Temperature Change ◽  
Radiative Forcing ◽  
Regional Scale ◽  
Temperature Response ◽  
The Arctic ◽  
Emission Region ◽  
So2 Emissions ◽  
Emission Changes

Abstract. Short-lived anthropogenic climate forcers, such as sulphate aerosols, affect both climate and air quality. Despite being short-lived, these forcers do not affect temperatures only locally; regions far away from the emission sources are also affected. Climate metrics are often used e.g. in a policy context to compare the climate impact of different anthropogenic forcing agents. These metrics typically relate a forcing change in a certain region with a temperature change in another region and thus often require a separate model to convert emission changes to radiative forcing changes. In this study, we used a coupled Earth System Model (NorESM) to calculate emission-to-temperature-response metrics for sulphur dioxide (SO2) emission changes in four different policy-relevant regions: Europe, North America, East Asia and South Asia. We first increased the SO2 emissions in each individual region by an amount giving approximately the same global average radiative forcing change (−0.45 W m−2). The global mean temperature change per unit sulphur emission compared to the control experiment was independent of emission region and equal to ∼ 0.006 K/TgSyr−1. On a regional scale, the Arctic showed the largest temperature response in all experiments. The second largest temperature change occurred in the region of the imposed emission increase, except when South Asian emissions were changed; in this experiment, the temperature response was approximately the same in South Asia and East Asia. We also examined the non-linearity of the temperature response by removing all anthropogenic SO2 emissions over Europe in one experiment. In this case, the temperature response (both global and regional) was twice of that in the corresponding experiment with a European emission increase. This nonlinearity in the temperature response is one of many uncertainties associated with the use of simplified climate metrics.

scholarly journals Reassessment of the common concept to derive the surface cloud radiative forcing in the Arctic: Consideration of surface albedo – cloud interactions

2019 ◽  
Author(s):  
Johannes Stapf ◽  
André Ehrlich ◽  
Evelyn Jäkel ◽  
Christof Lüpkes ◽  
Manfred Wendisch
Keyword(s):  
Radiative Forcing ◽  
Surface Albedo ◽  
Global Climate Models ◽  
Cooling Effect ◽  
The Arctic ◽  
Radiative Energy ◽  
Cloud Radiative Forcing ◽  
Airborne Measurements ◽  
Solar Cooling ◽  
Snow And Ice

Abstract. The concept of cloud radiative forcing (CRF) is commonly used to quantify the warming or cooling effect due to clouds on the radiative energy budget (REB). In the Arctic, radiative interactions between micro- and macrophysical properties of clouds and the surface influence the CRF and complicate its estimate obtained from observations or models. In this study the individual components and processes related to the surface CRF are analysed separately using simulations and measurement from low-level airborne observations of the REB in the heterogeneous springtime marginal sea ice zone (MIZ). The measurements were obtained during the Arctic CLoud Observations Using airborne measurements during polar Day (ACLOUD) campaign. The effect of changing surface albedo, due to the presence of clouds, and its dependence on cloud optical thickness was found to be relevant for the estimation of the solar CRF. A method to correct this albedo effect by retrieving the cloud-free surface albedo from observations under cloudy conditions is proposed. The application of this new concept to ACLOUD data shows, that the estimated average solar cooling effect by clouds almost doubles over snow and ice covered surfaces (−63 W m−2 instead of −33 W m−2), if surface albedo-cloud interactions are considered. Concerning the seasonal cycle of the surface albedo, this effect would potentially enhance solar cooling in periods where cold snow and ice dominate the surface and weaken the cooling by optical thin clouds and surface albedos commonly found during the summertime Arctic melting season. These findings suggest, that the surface albedo-cloud interaction needs to be represented in global climate models and in long-term observations to obtain a realistic estimate of the solar CRF and a reasonable representation of cloud radiative feedback mechanisms in the Arctic and to quantify the role of clouds in Arctic amplification.

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