scholarly journals Processes shaping the spatial pattern and seasonality of the surface air temperature response to anthropogenic forcing

2020 ◽  
Vol 54 (9-10) ◽  
pp. 3959-3975 ◽  
Author(s):  
Fangxing Tian ◽  
Buwen Dong ◽  
Jon Robson ◽  
Rowan Sutton ◽  
Laura Wilcox
Keyword(s):  
Spatial Pattern ◽  
Air Temperature ◽  
Temperature Response ◽  
Surface Air Temperature ◽  
Anthropogenic Forcing

scholarly journals Air Temperature and Anthropogenic Forcing: Insights from the Solid Earth

2011 ◽  
Vol 24 (2) ◽  
pp. 569-574 ◽  
Author(s):  
Jean O. Dickey ◽  
Steven L. Marcus ◽  
Olivier de Viron
Keyword(s):  
Air Temperature ◽  
Decadal Variability ◽  
Surface Air Temperature ◽  
Radiation Budget ◽  
Cloud Formation ◽  
Length Of Day ◽  
Anthropogenic Forcing ◽  
The Core ◽  
Earth’S Radiation Budget ◽  
Gas Effect

Abstract Earth’s rotation rate [i.e., length of day (LOD)], the angular momentum of the core (CAM), and surface air temperature (SAT) all have decadal variability. Previous investigators have found that the LOD fluctuations are largely attributed to core–mantle interactions and that the SAT is strongly anticorrelated with the decadal LOD. It is shown here that 1) the correlation among these three quantities exists until 1930, at which time anthropogenic forcing becomes highly significant; 2) correcting for anthropogenic effects, the correlation is present for the full span with a broadband variability centered at 78 yr; and 3) this result underscores the reality of anthropogenic temperature change, its size, and its temporal growth. The cause of this common variability needs to be further investigated and studied. Since temperature cannot affect the CAM or LOD to a sufficient extent, the results favor either a direct effect of Earth’s core-generated magnetic field (e.g., through the modulation of charged-particle fluxes, which may impact cloud formation) or a more indirect effect of some other core process on the climate—or yet another process that affects both. In all three cases, their signals would be much smaller than the anthropogenic greenhouse gas effect on Earth’s radiation budget during the coming century.

scholarly journals Quantifying the contribution of anthropogenic influence to the East Asian winter monsoon in 1960–2012

2019 ◽  
Vol 19 (15) ◽  
pp. 9903-9911
Author(s):  
Xin Hao ◽  
Shengping He ◽  
Huijun Wang ◽  
Tingting Han
Keyword(s):  
Air Temperature ◽  
General Circulation ◽  
East Asian Winter Monsoon ◽  
East Asian ◽  
Surface Air Temperature ◽  
Circulation Model ◽  
Winter Monsoon ◽  
Anthropogenic Influence ◽  
Anthropogenic Forcing ◽  
Asian Winter Monsoon

Abstract. The East Asian winter monsoon (EAWM) is greatly influenced by many factors that can be classified as anthropogenic forcing and natural forcing. Here we explore the contribution of anthropogenic influence to the change in the EAWM over the past decades. Under all forcings observed during 1960–2013 (All-Hist run), the atmospheric general circulation model is able to reproduce the climatology and variability of the EAWM-related surface air temperature and 500 hPa geopotential height and shows a statistically significant decreasing EAWM intensity with a trend coefficient of ∼-0.04 yr−1, which is close to the observed trend. By contrast, the simulation, which is driven by the same forcing as the All-Hist run but with the anthropogenic contribution to them removed, shows no decreasing trend in the EAWM intensity. By comparing the simulations under two different forcing scenarios, we further reveal that the responses of the EAWM to the anthropogenic forcing include a rise of 0.6∘ in surface air temperature over East Asia as well as weakening of the East Asian trough, which may result from the poleward expansion and intensification of the East Asian jet forced by the change in temperature gradient in the troposphere. Additionally, compared with the simulation without anthropogenic forcing, the frequency of strong (weak) EAWM occurrence is reduced (increased) by 45 % (from 0 to 10/7). These results indicate that the weakening of the EAWM during 1960–2013 may be mainly attributed to the anthropogenic influence.

scholarly journals Impact of stratospheric aerosol intervention geoengineering on surface air temperature in China: A surface energy budget perspective

2021 ◽  
Author(s):  
Zhaochen Liu ◽  
Xianmei Lang ◽  
Dabang Jiang
Keyword(s):  
Spatial Pattern ◽  
Air Temperature ◽  
Land Surface ◽  
Surface Albedo ◽  
Surface Air Temperature ◽  
Stratospheric Aerosol ◽  
Surface Energy Budget ◽  
Shortwave Radiation ◽  
Surface Cooling ◽  
Temperature Changes

Abstract. Stratospheric aerosol intervention (SAI) geoengineering is a rapid, effective, and promising means to counteract anthropogenic global warming, but the climate response to SAI, with great regional disparities, remains uncertain. In this study, we use Geoengineering Model Intercomparison Project G4 experiment simulations from three models (HadGEM2-ES, MIROC-ESM, and MIROC-ESM-CHEM) that offset anthropogenic forcing under medium-low emissions (RCP4.5) by injecting a certain amount of SO2 into the stratosphere every year, to investigate the surface air temperature response to SAI geoengineering over China. It has been shown that the SAI leads to surface cooling over China over the last 40 years of injection simulation (2030–2069), which varies among models, regions and seasons. The spatial pattern of SAI-induced temperature changes over China is mainly due to net surface shortwave radiation changes. We find that changes in solar radiation modification strength, surface albedo, atmospheric water vapor and cloudiness affect surface shortwave radiation. In summer, the increased cloud cover in some regions reduces net surface shortwave radiation, causing strong surface cooling. In winter, both the strong cooling in all three models and the abnormal warming in MIROC-ESM are related to surface albedo changes. Our results suggest that cloud and land surface processes in models may dominate the spatial pattern of SAI-induced surface air temperature changes over China.

scholarly journals Drivers of modern New Zealand glacier change

2021 ◽  
Author(s):  
◽  
Lauren Vargo
Keyword(s):  
New Zealand ◽  
Mass Loss ◽  
Air Temperature ◽  
Surface Air Temperature ◽  
High Mass ◽  
Glacier Change ◽  
Anthropogenic Influence ◽  
Positive Temperature ◽  
Anthropogenic Forcing ◽  
Temperature Anomalies

<p>Glaciers across the Southern Alps of New Zealand have been photographed annually since 1977, creating a rare record of Southern Hemisphere glacier change. Here, we revisit these historic photographs and use structure from motion photogrammetry to quantitatively measure glacier change from the images. To establish this new method, it is initially applied to Brewster Glacier (1670 – 2400 m a.s.l.), one of the 50 monitored glaciers. We derive annual equilibrium line altitude (ELA) and length records from 1981 – 2017, and quantify the uncertainties associated with the method. Our length reconstruction shows largely continuous terminus retreat of 365 ± 12 m for Brewster Glacier since 1981. The ELA record, which compares well with glaciological mass-balance data measured between 2005 and 2015, shows pronounced interannual variability. Mean ELAs range from 1707 ± 6 m a.s.l. to 2303 ± 5 m a.s.l. The newly developed ELA chronology from Brewster shows several years since 1981 with especially high mass loss, all of which occurred in the past decade. Investigation using reanalysis data shows that these extreme mass-loss years occur when surface air temperatures, sea surface temperatures, and mean sea level pressure are anomalously high. In particular, the three highest mass-loss years on record, 2011, 2016, and 2018, each had a 2-month mean surface air temperature anomaly of at least +1.7°C between November and March, which is exclusive to these three years over the time investigated (April 1980 – March 2018). Using event attribution — a methodology using climate model simulations with and without human-induced forcings to calculate the anthropogenic influence on extreme events — we calculate the anthropogenic influence on these surface air temperature anomalies. The positive temperature anomalies during extreme mass-loss years have probabilities of 0 – 90% confidence) more likely to occur with anthropogenic forcing, and in once case in 2018 could not have occurred (>90% confidence) without anthropogenic forcing. This increased likelihood is driven by present-day temperatures ~1.0°C above the pre-industrial average, confirming a connection between rising anthropogenic greenhouse gases, warming temperatures, and high annual ice loss.</p>

scholarly journals Quantifying the contribution of anthropogenic influence to the East Asian winter monsoon in 1960–2012

2019 ◽  
Author(s):  
Xin Hao ◽  
Shengping He ◽  
Huijun Wang ◽  
Tingting Han
Keyword(s):  
East Asia ◽  
Air Temperature ◽  
General Circulation ◽  
East Asian Winter Monsoon ◽  
East Asian ◽  
Surface Air Temperature ◽  
Winter Monsoon ◽  
Anthropogenic Influence ◽  
Anthropogenic Forcing ◽  
Asian Winter Monsoon

Abstract. The East Asian winter monsoon (EAWM) can be greatly influenced by many factors that can be classified as anthropogenic forcing and natural forcing. Here we explore the contribution of anthropogenic influence to the change in the EAWM over the past decades. Under all forcings observed during 1960–2013 (All-Hist run), the atmospheric general circulation model is able to reproduce the climatology and variability of the EAWM-related surface air temperature and 500 hPa geopotential height, and shows a statistically significant decreasing EAWM intensity with a trend coefficient of ∼−0.04 yr−1 which is close to the observed trend. By contrast, the simulation, which is driven by the same forcing as All-Hist run but with the anthropogenic contribution to them removed, shows no decreasing trend in the EAWM intensity. By comparing the simulations under two different forcing scenarios, we further reveal that the responses of the EAWM to the anthropogenic forcing include a rise of 0.6 ° in surface air temperature over the East Asia as well as weakening of the East Asia trough, which may result from the poleward expansion and intensification of the East Asian jet forced by the change of temperature gradient in the troposphere. Additionally, compared with the simulation without anthropogenic forcing, the frequency of strong (weak) EAWM occurrence is reduced (increased) by 45 % (from 0 to 10/7). These results indicate that the weakening of the EAWM during 1960–2013 may be mainly attributed to the anthropogenic influence.

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