Uncertainties in Radiative Forcing due to Surface Albedo Changes Caused by Land-Use Changes

Abstract A radiative transfer model has been used for estimating the radiative forcing due to land-use changes. Five global datasets for current vegetation cover and three datasets of preagriculture vegetation have been adopted. The vegetation datasets have been combined with three datasets for surface albedo values. A distinct feature in all the calculations is the negative radiative forcing at the northern midlatitudes due to the conversion of forest to cropland. Regionally the radiative forcing is likely to be among the strongest of the climate forcing mechanisms. A wider range is estimated for the global mean radiative forcing due to land-use changes than previously reported. The single most important factor yielding the large range in estimated forcing is the cropland surface albedo values. This underlines the importance of characterizing surface albedo correctly.

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Radiative forcing over the Arctic of aerosols from the August 2017 Canadian and Greenlandic wildfires

10.5194/egusphere-egu21-7405 ◽

2021 ◽

Author(s):

Filippo Calì Quaglia ◽

Daniela Meloni ◽

Alcide Giorgio di Sarra ◽

Tatiana Di Iorio ◽

Virginia Ciardini ◽

...

Keyword(s):

Radiative Transfer ◽

Radiative Forcing ◽

Solar Zenith Angle ◽

Surface Albedo ◽

High Arctic ◽

The Arctic ◽

Radiative Transfer Model ◽

Transfer Model ◽

Aerosol Layer ◽

Radiative Effect

Extended and intense wildfires occurred in Northern Canada and, unexpectedly, on the Greenlandic West coast during summer 2017. The thick smoke plume emitted into the atmosphere was transported to the high Arctic, producing one of the largest impacts ever observed in the region. Evidence of Canadian and Greenlandic wildfires was recorded at the Thule High Arctic Atmospheric Observatory (THAAO, 76.5&#176;N, 68.8&#176;W, www.thuleatmos-it.it) by a suite of instruments managed by ENEA, INGV, Univ. of Florence, and NCAR. Ground-based observations of the radiation budget have allowed quantification of the surface radiative forcing at THAAO.&#160;Excess biomass burning chemical tracers such as CO, HCN, H2CO, C2H6, and NH3 were&#160; measured in the air column above Thule starting from August 19 until August 23. The aerosol optical depth (AOD) reached a peak value of about 0.9 on August 21, while an enhancement of wildfire compounds was&#160; detected in PM10. The measured shortwave radiative forcing was -36.7 W/m2 at 78&#176; solar zenith angle (SZA) for AOD=0.626.MODTRAN6.0 radiative transfer model (Berk et al., 2014) was used to estimate the aerosol radiative effect and the heating rate profiles at 78&#176; SZA. Measured temperature profiles, integrated water vapour, surface albedo, spectral AOD and aerosol extinction profiles from CALIOP onboard CALIPSO were used as model input. The peak&#160; aerosol heating rate (+0.5 K/day) was&#160; reached within the aerosol layer between 8 and 12 km, while the maximum radiative effect (-45.4 W/m2) is found at 3 km, below the largest aerosol layer.The regional impact of the event that occurred on August 21 was investigated using a combination of atmospheric radiative transfer modelling with measurements of AOD and ground surface albedo from MODIS. The aerosol properties used in the radiative transfer model were constrained by in situ measurements from THAAO. Albedo data over the ocean have been obtained from Jin et al. (2004). Backward trajectories produced through HYSPLIT simulations (Stein et al., 2015) were also employed to trace biomass burning plumes.The radiative forcing efficiency (RFE) over land and ocean was derived, finding values spanning from -3 W/m2 to -132 W/m2, depending on surface albedo and solar zenith angle. The fire plume covered a vast portion of the Arctic, with large values of the daily shortwave RF (< -50 W/m2) lasting for a few days. This large amount of aerosol is expected to influence cloud properties in the Arctic, producing significant indirect radiative effects.

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Aerosol size distribution and radiative forcing response to anthropogenically driven historical changes in biogenic secondary organic aerosol formation

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-14-26297-2014 ◽

2014 ◽

Vol 14 (19) ◽

pp. 26297-26348

Author(s):

S. D. D'Andrea ◽

J. C. Acosta Navarro ◽

S. C. Farina ◽

C. E. Scott ◽

A. Rap ◽

...

Keyword(s):

Land Use ◽

Radiative Forcing ◽

Secondary Organic Aerosol ◽

Land Use Changes ◽

Organic Aerosol ◽

Anthropogenic Emissions ◽

The Past ◽

Year 2000 ◽

Global Mean ◽

Past Millennium

Abstract. Emissions of biogenic volatile organic compounds (BVOC) have changed in the past millennium due to changes in land use, temperature and CO2 concentrations. Recent model reconstructions of BVOC emissions over the past millennium predicted changes in dominant secondary organic aerosol (SOA) producing BVOC classes (isoprene, monoterpenes and sesquiterpenes). The reconstructions predicted that global isoprene emissions have decreased (land-use changes to crop/grazing land dominate the reduction), while monoterpene and sesquiterpene emissions have increased (temperature increases dominate the increases); however, all three show regional variability due to competition between the various influencing factors. These BVOC changes have largely been anthropogenic in nature, and land-use change was shown to have the most dramatic effect by decreasing isoprene emissions. In this work, we use two modeled estimates of BVOC emissions from the years 1000 to 2000 to test the effect of anthropogenic changes to BVOC emissions on SOA formation, global aerosol size distributions, and radiative effects using the GEOS-Chem-TOMAS global aerosol microphysics model. With anthropogenic emissions (e.g. SO2, NOx, primary aerosols) held at present day values and BVOC emissions changed from year 1000 to year 2000 values, decreases in the number concentration of particles of size Dp > 80 nm (N80) of >25% in year 2000 relative to year 1000 were predicted in regions with extensive land-use changes since year 1000 which led to regional increases in direct plus indirect aerosol radiative effect of >0.5 W m−2 in these regions. We test the sensitivity of our results to BVOC emissions inventory, SOA yields and the presence of anthropogenic emissions; however, the qualitative response of the model to historic BVOC changes remains the same in all cases. Accounting for these uncertainties, we estimate millennial changes in BVOC emissions cause a global mean direct effect of between +0.022 and +0.163 W m−2 and the global mean cloud-albedo aerosol indirect effect of between −0.008 and −0.056 W m−2. This change in aerosols, and the associated radiative forcing, could be a~largely overlooked and important anthropogenic aerosol effect on regional climates.

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Technical Note: Evaluating a simple parameterization of radiative shortwave forcing from surface albedo change

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-13-18951-2013 ◽

2013 ◽

Vol 13 (7) ◽

pp. 18951-18967 ◽

Cited By ~ 2

Author(s):

R. M. Bright ◽

M. M. Kvalevåg

Keyword(s):

Land Use ◽

Simple Model ◽

Impact Assessment ◽

Surface Albedo ◽

Climate Impact ◽

Technical Note ◽

Radiative Transfer Model ◽

Transfer Model ◽

Model Based ◽

Albedo Change

Abstract. Land use activities affect Earth's energy balance not only via biogeochemical emissions but also through perturbations in surface albedo, the latter of which is often excluded in impact assessment studies. In this short technical note, we present and compare a simple model for estimating shortwave radiative forcings at the top of Earth's atmosphere to a more sophisticated 8-stream radiative transfer model based on a discrete ordinate method. Outcomes from monthly albedo change simulations for ten globally distributed regions and a single year revealed that the simple model – based on a single exogenously supplied meteorological variable – performed quite well, having a sample correlation coefficient of 0.93 and a normalized root mean square error of 7.2%. Simple models like the one presented here can offer an attractive and efficient means for non-experts to begin including albedo change considerations in climate impact assessment studies enveloping land use activities.

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Technical Note: Evaluating a simple parameterization of radiative shortwave forcing from surface albedo change

Atmospheric Chemistry and Physics ◽

10.5194/acp-13-11169-2013 ◽

2013 ◽

Vol 13 (22) ◽

pp. 11169-11174 ◽

Cited By ~ 13

Author(s):

R. M. Bright ◽

M. M. Kvalevåg

Keyword(s):

Land Use ◽

Simple Model ◽

Impact Assessment ◽

Surface Albedo ◽

Climate Impact ◽

Technical Note ◽

Radiative Transfer Model ◽

Transfer Model ◽

Model Based ◽

Albedo Change

Abstract. Land-use activities affect Earth's energy balance not only via biogeochemical emissions, but also through perturbations in surface albedo, the latter of which is often excluded in impact assessment studies. In this short technical note, we present and compare a simple model for estimating shortwave radiative forcings at the top of Earth's atmosphere to a more sophisticated 8-stream radiative transfer model based on a discrete ordinate method. Outcomes from monthly albedo change simulations for ten globally distributed regions and a single year revealed that the simple model – based on a single exogenously supplied meteorological variable – performed quite well, having a sample correlation coefficient of 0.93 and a normalized root mean square error of 7.2%. Simple models like the one presented here can offer an attractive and efficient means for non-experts to begin including albedo change considerations in climate impact assessment studies enveloping land use activities.

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Uncertainties in Radiative Forcing due to Surface Albedo Changes Caused by Land-Use Changes

Journal of Climate ◽

10.1175/1520-0442(2003)016<1511:uirfdt>2.0.co;2 ◽

2003 ◽

Vol 16 (10) ◽

pp. 1511-1524 ◽

Cited By ~ 1

Keyword(s):

Land Use ◽

Radiative Forcing ◽

Surface Albedo ◽

Land Use Changes

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Using surface remote sensors to derive mixed-phase cloud radiative forcing: an example from M-PACE

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-11-12487-2011 ◽

2011 ◽

Vol 11 (4) ◽

pp. 12487-12518 ◽

Cited By ~ 1

Author(s):

G. de Boer ◽

W. D. Collins ◽

S. Menon ◽

C. N. Long

Keyword(s):

Radiative Forcing ◽

Surface Albedo ◽

The United States ◽

Surface Fluxes ◽

Mixed Phase ◽

Department Of Energy ◽

Radiative Transfer Model ◽

Transfer Model ◽

United States Department ◽

Cloud Radiative Forcing

Abstract. A suite of ground-based measurements are used in conjunction with a column version of the Rapid Radiative Transfer Model (RRTMG) to derive the cloud radiative forcing of mixed-phase stratiform clouds observed during the United States Department of Energy (US DOE) Atmospheric Radiation Measurement (ARM) Mixed-Phase Arctic Clouds Experiment (M-PACE) between September and November of 2004. In total, sixteen half hour time periods are reviewed due to their coincidence with radiosonde launches. Cloud liquid (ice) water paths are found to range between 11.0–366.4 (0.5–114.1) gm−2, and cloud physical thicknesses fall between 286–2075 m. Combined with temperature and hydrometeor size estimates, this information is used to calculate surface radiative fluxes using RRTMG, which are demonstrated to generally agree with measured fluxes from surface-based radiometric instrumentation. Errors in longwave flux estimates are found to be largest for thin clouds, while shortwave flux errors are generally largest for thicker clouds. Cloud radiative forcing is calculated for all profiles, and illustrates the dominance of the longwave component during this time of year, with net cloud forcing generally between 50 and 90 Wm−2. Finally, sensitivity of calculated surface fluxes to droplet effective radius, surface albedo and surface temperature are tested, with changes in minimum droplet size between 3.5 and 10 μm altering the surface shortwave flux by up to 50 Wm−2, and changes in surface albedo between 0.5 and 0.95 altering surface shortwave fluxes by up to 85 Wm−2.

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Spatial-Temporal Variation of Snow Black Carbon Concentration in Snow Cover in Northeast China from 2001 to 2016 Based on Remote Sensing

Sustainability ◽

10.3390/su14020959 ◽

2022 ◽

Vol 14 (2) ◽

pp. 959

Author(s):

Yanjiao Zheng ◽

Lijuan Zhang ◽

Wenliang Li ◽

Fan Zhang ◽

Xinyue Zhong

Keyword(s):

Black Carbon ◽

Human Activities ◽

Northeast China ◽

Radiative Forcing ◽

Surface Albedo ◽

Global Climate ◽

Atmospheric Stability ◽

Radiative Transfer Model ◽

Transfer Model ◽

Snow Surface

The amount of black carbon (BC) on snow surface can significantly reduce snow surface albedo in the visible-light range and change the surface radiative forcing effect. Therefore, it is key to study regional and global climate changes to understand the BC concentration on snow. In this study, we simulated the BC concentration on the surface snow of northeast China using an asymptotic radiative transfer model. From 2001 to 2016, the BC concentration showed no significant increase, with an average increase of 82.104 ng/g compared with that in the early 21st century. The concentration of BC in December was the largest (1344.588 ng/g) and decreased in January and February (1248.619 ng/g and 983.635 ng/g, respectively). The high black carbon content centers were concentrated in the eastern and central regions with dense populations and concentrated industries, with a concentration above 1200 ng/g, while the BC concentration in the southwest region with less human activities was the lowest (below 850 ng/g), which indicates that human activities played an important role in snow BC pollution. Notably, Heilongjiang province has the highest concentration, which may be related to its atmospheric stability in winter. These findings suggest that the BC pollution in northeast China has been aggravated from 2001 to 2016. It is estimated that the snow surface albedo will decrease by 16.448% due to the BC pollution of snow in northeast China. The problem of radiative forcing caused by black carbon to snow reflectivity cannot be ignored.

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The direct and indirect radiative effects of biogenic secondary organic aerosol

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-13-16961-2013 ◽

2013 ◽

Vol 13 (6) ◽

pp. 16961-17019 ◽

Cited By ~ 6

Author(s):

C. E. Scott ◽

A. Rap ◽

D. V. Spracklen ◽

P. M. Forster ◽

K. S. Carslaw ◽

...

Keyword(s):

Radiative Forcing ◽

Secondary Organic Aerosol ◽

Organic Aerosol ◽

Radiative Transfer Model ◽

Anthropogenic Emissions ◽

Transfer Model ◽

Particle Nucleation ◽

Radiative Effect ◽

Radiative Impact ◽

Global Mean

Abstract. We use a global aerosol microphysics model in combination with an offline radiative transfer model to quantify the radiative effect of biogenic secondary organic aerosol (SOA) in the present day atmosphere. Through its role in particle growth and ageing, the presence of biogenic SOA increases the global annual mean concentration of cloud condensation nuclei (CCN; at 0.2% supersaturation) by 3.6–21.1%, depending upon the yield of SOA production, and the nature and treatment of concurrent primary carbonaceous emissions. This increase in CCN causes a rise in global annual mean cloud droplet number concentration (CDNC) of 1.9–5.2%, and a global mean first aerosol indirect effect (AIE) of between +0.01 W m−2 and −0.12 W m−2. The radiative impact of biogenic SOA is far greater when it also contributes to particle nucleation; using two organically-mediated mechanisms for new particle formation we simulate global annual mean AIEs of −0.22 W m−2 and −0.77 W m−2. The inclusion of biogenic SOA substantially improves the simulated seasonal cycle in the concentration of CCN sized particles observed at three forested sites. The best correlation is found when the organically-mediated nucleation mechanisms are applied, suggesting that the AIE of biogenic SOA could be as large as −0.77 W m−2. The radiative impact of SOA is sensitive to the presence of anthropogenic emissions. Lower background aerosol concentrations simulated with anthropogenic emissions from 1750 give rise to a greater fractional CCN increase and a more substantial indirect radiative effect from biogenic SOA. Consequently, the anthropogenic indirect radiative forcing between 1750 and the present day is sensitive to assumptions about the amount and role of biogenic SOA. We also calculate an annual global mean direct radiative effect (DRE) of between −0.08 W m−2 and −0.78 W m−2 in the present day, with uncertainty in the amount of SOA produced from the oxidation of biogenic volatile organic compounds (BVOCs) accounting for most of this range.

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Influence of Land Use Change on the Surface Albedo and Climate Change in the Qinling-Daba Mountains

Sustainability ◽

10.3390/su131810153 ◽

2021 ◽

Vol 13 (18) ◽

pp. 10153

Author(s):

Fang Zhao ◽

Xincan Lan ◽

Wuyang Li ◽

Wenbo Zhu ◽

Tianqi Li

Keyword(s):

Climate Change ◽

Land Use ◽

Radiative Forcing ◽

Surface Albedo ◽

Global Climate ◽

Land Use Changes ◽

Mountainous Area ◽

Land Area ◽

Climate Change Effects ◽

Land Use Types

Land use changes affect the surface radiative budget and energy balance by changing the surface albedo, which generates radiative forcing, impacting the regional and global climate. To estimate the effect of land use changes on the surface albedo and climate change in a mountainous area with complex terrain, we obtained MODIS data, identified the spatial–temporal characteristics of the surface albedo caused by land use changes, and then calculated the radiative forcing based on solar radiative data and the surface albedo in the Qinling-Daba mountains from 2000 to 2015. The correlation between the land use changes and the radiative forcing was analyzed to explore the climate effects caused by land use changes on a kilometer-grid scale in the Qinling-Daba mountains. Our results show that the primarily land use changes were a decrease in the cultivated land area and an increase in the construction land area, as well as other conversions between six land use types from 2000 to 2015. The land use changes led to significant changes in the surface albedo. Meanwhile, the radiative forcing caused by the land use had different magnitudes, strengths, and occurrence ranges, resulting in both warming and cooling climate change effects.

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Drivers of (non-)linear Eocene surface warming in the DeepMIP ensemble

10.5194/egusphere-egu21-14127 ◽

2021 ◽

Author(s):

Sebastian Steinig ◽

Jiang Zhu ◽

Ran Feng ◽

Keyword(s):

Temperature Gradient ◽

Heat Transport ◽

Climate Sensitivity ◽

Radiative Forcing ◽

Large Scale ◽

Surface Albedo ◽

Early Eocene ◽

Meridional Heat Transport ◽

Surface Warming ◽

Global Mean

The early Eocene greenhouse represents the warmest interval of the Cenozoic and therefore provides a unique opportunity to understand how the climate system operates under elevated atmospheric CO2 levels similar to those projected for the end of the 21st century. Early Eocene geological records indicate a large increase in global mean surface temperatures compared to present day (by ~14&#176;C) and a greatly reduced meridional temperature gradient (by ~30% in SST). However, reproducing these large-scale climate features at reasonable CO2 levels still poses a challenge for current climate models. Recent modelling studies indicate an important role for shortwave (SW) cloud feedbacks to drive increases in climate sensitivity with global warming, which helps to close the gap between simulated and reconstructed Eocene global warmth and temperature gradient. Nevertheless, the presence of such state-dependent feedbacks and their relative strengths in other models remain unclear.In this study, we perform a systematic investigation of the simulated surface warming and the underlying mechanisms in the recently published DeepMIP ensemble. The DeepMIP early Eocene simulations use identical paleogeographic boundary conditions and include six models with suitable output: CESM1.2_CAM5, GFDL_CM2.1, HadCM3B_M2.1aN, IPSLCM5A2, MIROC4m and NorESM1_F. We advance previous energy balance analysis by applying the approximate partial radiative perturbation (APRP) technique to quantify the individual contributions of surface albedo, cloud and non-cloud atmospheric changes to the simulated Eocene top-of-the-atmosphere SW flux anomalies. We further compare the strength of these planetary albedo feedbacks to changes in the longwave atmospheric emissivity and meridional heat transport in the warm Eocene climate. Particular focus lies in the sensitivity of the feedback strengths to increasing global mean temperatures in experiments at a range of atmospheric CO2 concentrations between x1 to x9 preindustrial levels.Preliminary results indicate that all models that provide data for at least 3 different CO2 levels show an increase of the equilibrium climate sensitivity at higher global mean temperatures. This is associated with an increase of the overall strength of the positive SW cloud feedback with warming in those models. This nonlinear behavior seems to be related to both a reduction and optical thinning of low-level clouds, albeit with intermodel differences in the relative importance of the two mechanisms. We further show that our new APRP results can differ significantly from previous estimates based on cloud radiative forcing alone, especially in high-latitude areas with large surface albedo changes. We also find large intermodel variability and state-dependence in meridional heat transport modulated by changes in the atmospheric latent heat transport. Ongoing work focuses on the spatial patterns of the climate feedbacks and the implications for the simulated meridional temperature gradients.

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