Attribution of Projected Changes in Atmospheric Moisture Transport in the Arctic: A Self-Organizing Map Perspective

2009 ◽  
Vol 22 (15) ◽  
pp. 4135-4153 ◽  
Author(s):  
Natasa Skific ◽  
Jennifer A. Francis ◽  
John J. Cassano
Keyword(s):  
Twentieth Century ◽  
Moisture Transport ◽  
First Century ◽  
The Arctic ◽  
Self Organizing Map ◽  
Total Change ◽  
Intergovernmental Panel ◽  
Climate System Model ◽  
Twenty First Century ◽  
Self Organizing

Abstract Meridonal moisture transport into the Arctic derived from one simulation of the National Center for Atmospheric Research Community Climate System Model (CCSM3), spanning the periods of 1960–99, 2010–30, and 2070–89, is analyzed. The twenty-first-century simulation incorporates the Intergovernmental Panel on Climate Change (IPCC) Special Report on Emission Scenarios (SRES) A2 scenario for CO2 and sulfate emissions. Modeled and observed [from the 40-yr ECMWF Re-Analysis (ERA-40)] sea level pressure (SLP) fields are classified using a neural network technique called self-organizing maps to distill a set of characteristic atmospheric circulation patterns over the region north of 60°N. Model performance is validated for the twentieth century by comparing the frequencies of occurrence of particular circulation regimes in the model to those from the ERA-40. The model successfully captures dominant SLP patterns, but differs from observations in the frequency with which certain patterns occur. The model’s twentieth-century vertical mean moisture transport profile across 70°N compares well in terms of structure but exceeds the observations by about 12% overall. By relating moisture transport to a particular circulation regime, future changes in moisture transport across 70°N are assessed and attributed to changes in frequency with which the atmosphere resides in particular SLP patterns and/or to other factors, such as changes in the meridional moisture gradient. By the late twenty-first century, the transport is projected to increase by about 21% in this model realization, with the largest contribution (32%) to the total change occurring in summer. Only about one-quarter of the annual increase is due to changes in pattern occupancy, suggesting that the majority is related to mainly thermodynamic factors. A larger poleward moisture transport likely constitutes a positive feedback on the system through related increases in latent heat release and the emission of longwave radiation to the surface.

scholarly journals Climate System Response to External Forcings and Climate Change Projections in CCSM4

2012 ◽  
Vol 25 (11) ◽  
pp. 3661-3683 ◽  
Author(s):  
Gerald A. Meehl ◽  
Warren M. Washington ◽  
Julie M. Arblaster ◽  
Aixue Hu ◽  
Haiyan Teng ◽  
...  
Keyword(s):  
Twentieth Century ◽  
Sea Ice ◽  
Meridional Overturning Circulation ◽  
Climate System ◽  
First Century ◽  
The Arctic ◽  
System Response ◽  
Transient Climate Response ◽  
Climate System Model ◽  
Twenty First Century

Results are presented from experiments performed with the Community Climate System Model, version 4 (CCSM4) for the Coupled Model Intercomparison Project phase 5 (CMIP5). These include multiple ensemble members of twentieth-century climate with anthropogenic and natural forcings as well as single-forcing runs, sensitivity experiments with sulfate aerosol forcing, twenty-first-century representative concentration pathway (RCP) mitigation scenarios, and extensions for those scenarios beyond 2100–2300. Equilibrium climate sensitivity of CCSM4 is 3.20°C, and the transient climate response is 1.73°C. Global surface temperatures averaged for the last 20 years of the twenty-first century compared to the 1986–2005 reference period for six-member ensembles from CCSM4 are +0.85°, +1.64°, +2.09°, and +3.53°C for RCP2.6, RCP4.5, RCP6.0, and RCP8.5, respectively. The ocean meridional overturning circulation (MOC) in the Atlantic, which weakens during the twentieth century in the model, nearly recovers to early twentieth-century values in RCP2.6, partially recovers in RCP4.5 and RCP6, and does not recover by 2100 in RCP8.5. Heat wave intensity is projected to increase almost everywhere in CCSM4 in a future warmer climate, with the magnitude of the increase proportional to the forcing. Precipitation intensity is also projected to increase, with dry days increasing in most subtropical areas. For future climate, there is almost no summer sea ice left in the Arctic in the high RCP8.5 scenario by 2100, but in the low RCP2.6 scenario there is substantial sea ice remaining in summer at the end of the century.

Interhemispheric Temperature Asymmetry over the Twentieth Century and in Future Projections

2013 ◽  
Vol 26 (15) ◽  
pp. 5419-5433 ◽  
Author(s):  
Andrew R. Friedman ◽  
Yen-Ting Hwang ◽  
John C. H. Chiang ◽  
Dargan M. W. Frierson
Keyword(s):  
Twentieth Century ◽  
Global Climate ◽  
First Century ◽  
The Arctic ◽  
Positive Trend ◽  
Anthropogenic Aerosols ◽  
Abrupt Decrease ◽  
Tropical Rainfall ◽  
Twenty First Century ◽  
Temperature Asymmetry

Abstract The temperature contrast between the Northern and Southern Hemispheres—the interhemispheric temperature asymmetry (ITA)—is an emerging indicator of global climate change, potentially relevant to the Hadley circulation and tropical rainfall. The authors examine the ITA in historical observations and in phases 3 and 5 of the Coupled Model Intercomparison Project (CMIP3 and CMIP5) simulations. The observed annual-mean ITA (north minus south) has varied within a 0.8°C range and features a significant positive trend since 1980. The CMIP multimodel ensembles simulate this trend, with a stronger and more realistic signal in CMIP5. Both ensembles project a continued increase in the ITA over the twenty-first century, well outside the twentieth-century range. The authors mainly attribute this increase to the uneven spatial impacts of greenhouse forcing, which result in amplified warming in the Arctic and northern landmasses. The CMIP5 specific-forcing simulations indicate that, before 1980, the greenhouse-forced ITA trend was primarily countered by anthropogenic aerosols. The authors also identify an abrupt decrease in the observed ITA in the late 1960s, which is generally not present in the CMIP simulations; it suggests that the observed drop was caused by internal variability. The difference in the strengths of the northern and southern Hadley cells covaries with the ITA in the CMIP5 simulations, in accordance with previous findings; the authors also find an association with the hemispheric asymmetry in tropical rainfall. These relationships imply a northward shift in tropical rainfall with increasing ITA in the twenty-first century, though this result is difficult to separate from the response to global-mean temperature change.

Climate Change Projections for the Twenty-First Century and Climate Change Commitment in the CCSM3

2006 ◽  
Vol 19 (11) ◽  
pp. 2597-2616 ◽  
Author(s):  
Gerald A. Meehl ◽  
Warren M. Washington ◽  
Benjamin D. Santer ◽  
William D. Collins ◽  
Julie M. Arblaster ◽  
...  
Keyword(s):  
Climate Change ◽  
Twentieth Century ◽  
Sea Ice ◽  
Sea Level Rise ◽  
Sea Level ◽  
Climate System ◽  
First Century ◽  
Change Scenario ◽  
Climate System Model ◽  
Twenty First Century

Abstract Climate change scenario simulations with the Community Climate System Model version 3 (CCSM3), a global coupled climate model, show that if concentrations of all greenhouse gases (GHGs) could have been stabilized at the year 2000, the climate system would already be committed to 0.4°C more warming by the end of the twenty-first century. Committed sea level rise by 2100 is about an order of magnitude more, percentage-wise, compared to sea level rise simulated in the twentieth century. This increase in the model is produced only by thermal expansion of seawater, and does not take into account melt from ice sheets and glaciers, which could at least double that number. Several tenths of a degree of additional warming occurs in the model for the next 200 yr in the Intergovernmental Panel on Climate Change (IPCC) Special Report on Emissions Scenarios (SRES) B1 and A1B scenarios after stabilization in the year 2100, but with twice as much sea level rise after 100 yr, and doubling yet again in the next 100 yr to 2300. At the end of the twenty-first century, the warming in the tropical Pacific for the A2, A1B, and B1 scenarios resembles an El Niño–like response, likely due to cloud feedbacks in the model as shown in an earlier version. Greatest warming occurs at high northern latitudes and over continents. The monsoon regimes intensify somewhat in the future warmer climate, with decreases of sea level pressure at high latitudes and increases in the subtropics and parts of the midlatitudes. There is a weak summer midlatitude soil moisture drying in this model as documented in previous models. Sea ice distributions in both hemispheres are somewhat overextensive, but with about the right ice thickness at the end of the twentieth century. Future decreases in sea ice with global warming are proportional to the temperature response from the forcing scenarios, with the high forcing scenario, A2, producing an ice-free Arctic in summer by the year 2100.

Attribution of Seasonal and Regional Changes in Arctic Moisture Convergence

2009 ◽  
Vol 22 (19) ◽  
pp. 5115-5134 ◽  
Author(s):  
Natasa Skific ◽  
Jennifer A. Francis ◽  
John J. Cassano
Keyword(s):  
First Century ◽  
Moisture Convergence ◽  
Specific Humidity ◽  
Self Organizing Map ◽  
Sea Level Pressure ◽  
Climate System Model ◽  
Emissions Scenarios ◽  
Western Arctic ◽  
Twenty First Century ◽  
Area North

Abstract Spatial and temporal changes in high-latitude moisture convergence simulated by the National Center for Atmospheric Research Community Climate System Model, version 3 (CCSM3) are investigated. Moisture convergence is calculated using the aerological method with model fields of specific humidity and winds spanning the periods from 1960 to 1999 and 2070 to 2089. The twenty-first century incorporates the A2 scenario from the Special Report on Emissions Scenarios. The model’s realism in reproducing the twentieth-century moisture convergence is evaluated by comparison with values derived from the 40-yr ECMWF Re-Analysis (ERA-40). In the area north of 75°N, the simulated moisture convergence is similar to observations during summer, but it is larger in winter, spring, and autumn. The model also underestimates (overestimates) the mean annual moisture convergence in the eastern (western) Arctic. Late twenty-first century annual, seasonal, and regional changes are determined by applying a self-organizing map technique to the model’s sea level pressure fields to identify dominant atmospheric circulation regimes and their corresponding moisture convergence fields. Changes in moisture convergence from the twentieth to the twenty-first century result primarily from thermodynamic effects (∼70%), albeit shifts in the frequency of dominant circulation patterns exert a relatively large influence on future changes in the eastern Arctic. Increased moisture convergence in the central Arctic (North Atlantic) stems mainly from thermodynamic changes in summer (winter). Changes in the strength and location of poleward moisture gradients are most likely responsible for projected variations in moisture transport, which are in turn a consequence of increasing anthropogenic greenhouse gas emissions as prescribed by the A2 scenario.

Twenty-First-Century Arctic Climate Change in CCSM4

2012 ◽  
Vol 25 (8) ◽  
pp. 2696-2710 ◽  
Author(s):  
Stephen J. Vavrus ◽  
Marika M. Holland ◽  
Alexandra Jahn ◽  
David A. Bailey ◽  
Benjamin A. Blazey
Keyword(s):  
Climate Change ◽  
Arctic Ocean ◽  
Radiative Forcing ◽  
First Century ◽  
Arctic Climate ◽  
The Arctic ◽  
Climate System Model ◽  
Temperature Isotherm ◽  
Twenty First Century ◽  
Arctic Climate Change

Abstract The authors summarize the twenty-first-century Arctic climate simulated by NCAR’s Community Climate System Model, version 4 (CCSM4). Under a strong radiative forcing scenario, the model simulates a much warmer, wetter, cloudier, and stormier Arctic climate with considerably less sea ice and a fresher Arctic Ocean. The high correlation among the variables composing these changes—temperature, precipitation, cloudiness, sea level pressure (SLP), and ice concentration—suggests that their close coupling collectively represents a fingerprint of Arctic climate change. Although the projected changes in CCSM4 are generally consistent with those in other GCMs, several noteworthy features are identified. Despite more global warming in CCSM4, Arctic changes are generally less than under comparable greenhouse forcing in CCSM3, as represented by Arctic amplification (16% weaker) and the date of a seasonally ice-free Arctic Ocean (20 years later). Autumn is the season of the most pronounced Arctic climate change among all the primary variables. The changes are very similar across the five ensemble members, although SLP displays the largest internal variability. The SLP response exhibits a significant trend toward stronger extreme Arctic cyclones, implying greater wave activity that would promote coastal erosion. Based on a commonly used definition of the Arctic (the area encompassing the 10°C July air temperature isotherm), the region shrinks by about 40% during the twenty-first century, in conjunction with a nearly 10-K warming trend poleward of 70°N. Despite this pronounced long-term warming, CCSM4 simulates a hiatus in the secular Arctic climate trends during a decade-long stretch in the 2040s and to a lesser extent in the 2090s. These pauses occur despite averaging over five ensemble members and are remarkable because they happen under the most extreme greenhouse-forcing scenario and in the most climatically sensitive region of the world.

scholarly journals Corporate headquarters in the twenty-first century: an organization design perspective

2020 ◽  
Vol 9 (1) ◽  
Author(s):  
Sven Kunisch ◽  
Markus Menz ◽  
David Collis
Keyword(s):  
Twentieth Century ◽  
Organization Design ◽  
Business Environment ◽  
First Century ◽  
Future Research ◽  
Corporate Headquarters ◽  
Special Collection ◽  
Design Perspective ◽  
Twenty First Century

Abstract The corporate headquarters (CHQ) of the multi-business enterprise, which emerged as the dominant organizational form for the conduct of business in the twentieth century, has attracted considerable scholarly attention. As the business environment undergoes a fundamental transition in the twenty-first century, we believe that understanding the evolving role of the CHQ from an organization design perspective will offer unique insights into the nature of business activity in the future. The purpose of this article, in keeping with the theme of the Journal of Organization Design Special Collection, is thus to invigorate research into the CHQ. We begin by explicating four canonical questions related to the design of the CHQ. We then survey fundamental changes in the business environment occurring in the twenty-first century, and discuss their potential implications for CHQ design. When suitable here we also refer to the contributions published in our Special Collection. Finally, we put forward recommendations for advancements and new directions for future research to foster a deeper and broader understanding of the topic. We believe that we are on the cusp of a change in the CHQ as radical as that which saw its initial emergence in the late nineteenth/early twentieth century. Exactly what form that change will take remains for practitioners and researchers to inform.

scholarly journals Climate Change Projection in the Twenty-First Century Simulated by NIMS-KMA CMIP6 Model Based on New GHGs Concentration Pathways

2021 ◽  
Author(s):  
Hyun Min Sung ◽  
Jisun Kim ◽  
Sungbo Shim ◽  
Jeong-byn Seo ◽  
Sang-Hoon Kwon ◽  
...  
Keyword(s):  
Climate Change ◽  
Climate Changes ◽  
Scientific Information ◽  
Earth System Model ◽  
First Century ◽  
System Model ◽  
The Arctic ◽  
Earth System ◽  
Future Projections ◽  
Twenty First Century

AbstractThe National Institute of Meteorological Sciences-Korea Meteorological Administration (NIMS-KMA) has participated in the Coupled Model Inter-comparison Project (CMIP) and provided long-term simulations using the coupled climate model. The NIMS-KMA produces new future projections using the ensemble mean of KMA Advanced Community Earth system model (K-ACE) and UK Earth System Model version1 (UKESM1) simulations to provide scientific information of future climate changes. In this study, we analyze four experiments those conducted following the new shared socioeconomic pathway (SSP) based scenarios to examine projected climate change in the twenty-first century. Present day (PD) simulations show high performance skill in both climate mean and variability, which provide a reliability of the climate models and reduces the uncertainty in response to future forcing. In future projections, global temperature increases from 1.92 °C to 5.20 °C relative to the PD level (1995–2014). Global mean precipitation increases from 5.1% to 10.1% and sea ice extent decreases from 19% to 62% in the Arctic and from 18% to 54% in the Antarctic. In addition, climate changes are accelerating toward the late twenty-first century. Our CMIP6 simulations are released to the public through the Earth System Grid Federation (ESGF) international data sharing portal and are used to support the establishment of the national adaptation plan for climate change in South Korea.

‘A Heap of Broken Images’? Reviving Austro-German Debates over Musical Meaning, 1900–36

2013 ◽  
Vol 138 (1) ◽  
pp. 129-174 ◽  
Author(s):  
Matthew Pritchard
Keyword(s):  
Twentieth Century ◽  
Educational Theory ◽  
First Century ◽  
Critical Hermeneutics ◽  
Musical Meaning ◽  
Force And Motion ◽  
The Status ◽  
Musical Interpretation ◽  
Twenty First Century

AbstractThis article examines a range of writings on the status of musical interpretation in Austria and Germany during the early decades of the twentieth century, and argues their relevance to current debates. While the division outlined by recent research between popular-critical hermeneutics and analytical ‘energetics’ at this time remains important, hitherto neglected contemporary reflections by Paul Bekker and Kurt Westphal demonstrate that the success of energetics was not due to any straightforward intellectual victory. Rather, the images of force and motion promoted by 1920s analysis were carried by historical currents in the philosophy, educational theory and arts of the time, revealing a culturally situated source for twenty-first-century analysis's preoccupations with motion and embodiment. The cultural relativization of such images may serve as a retrospective counteraction to the analytical rationalizing processes that culminated specifically in Heinrich Schenker's later work, and more generally in the privileging of graphic and notational imagery over poetic paraphrase.

scholarly journals Evaluation of flood damage reduction throughout Japan from adaptation measures taken under a range of emissions mitigation scenarios

2021 ◽  
Vol 165 (3-4) ◽  
Author(s):  
Tao Yamamoto ◽  
So Kazama ◽  
Yoshiya Touge ◽  
Hayata Yanagihara ◽  
Tsuyoshi Tada ◽  
...  
Keyword(s):  
Twentieth Century ◽  
Flood Damage ◽  
First Century ◽  
Mitigation Measures ◽  
Damage Cost ◽  
Adaptation Measures ◽  
Inundation Depth ◽  
Late Twentieth ◽  
Twenty First Century ◽  
Late Twentieth Century

AbstractThis study aimed to evaluate the impact of climate change on flood damage and the effects of mitigation measures and combinations of multiple adaptation measures in reducing flood damage. The inundation depth was calculated using a two-dimensional unsteady flow model. The flood damage cost was estimated from the unit evaluation value set for each land use and prefectures and the calculated inundation depth distribution. To estimate the flood damage in the near future and the late twenty-first century, five global climate models were used. These models provided daily precipitation, and the change of the extreme precipitation was calculated. In addition to the assessment of the impacts of climate change, certain adaptation measures (land-use control, piloti building, and improvement of flood control level) were discussed, and their effects on flood damage cost reduction were evaluated. In the case of the representative concentration pathway (RCP) 8.5 scenario, the damage cost in the late twenty-first century will increase to 57% of that in the late twentieth century. However, if mitigation measures were to be undertaken according to RCP2.6 standards, the increase of the flood damage cost will stop, and the increase of the flood damage cost will be 28% of that in the late twentieth century. By implementing adaptation measures in combination rather than individually, it is possible to keep the damage cost in the future period even below that in the late twentieth century. By implementing both mitigation and adaptation measures, it is possible to reduce the flood damage cost in the late twenty-first century to 69% of that in the late twentieth century.

Out of the box, onto the web: Digitizing images in the Tuzin Archive for Melanesian Anthropology

2020 ◽  
Vol 8 (2) ◽  
pp. 251-268 ◽  
Author(s):  
Cristela Garcia-Spitz ◽  
Kathryn Creely
Keyword(s):  
Twentieth Century ◽  
San Diego ◽  
New Technologies ◽  
First Century ◽  
University Of California ◽  
Online Access ◽  
Twenty First Century ◽  
The University ◽  
Archival Practices ◽  
The Web

How are ethnographic photographs from the twentieth century accessed and represented in the twenty-first century? This report from the Tuzin Archive for Melanesian Anthropology at the University of California San Diego Library provides an overview of the photographic materials, arrangements and types of documentation in the archive, followed by summaries of specific digitization projects of the photographs from physician Sylvester Lambert and anthropologists Roger Keesing and Harold Scheffler, among others. Through the process of digitization and online access, ethnographic photographs are transformed and may be discovered and contextualized in new ways. Utilizing new technologies and forming broad collaborations, these digitization projects incorporate both anthropological and archival practices and also raise ethical questions. This is an in-depth look at what is digitized and how it is described to re/create meaning and context and to bring new life to these images.

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