bluuebunny/crossref_metadata_2025 huggingface dataset:
The Second Line of Defense
Authors: Dumenil Lynn
Published: September 2017

In tracing the rise of the modern idea of the American “new woman,” Lynn Dumenil examines World War I’s surprising impact on women and, in turn, women’s impact on the war. Telling the stories of a diverse group of women, including African Americans, dissidents, pacifists, reformers, and industrial workers, Dumenil analyzes both the roadblocks and opportunities they faced. She richly explores the ways in which women helped the United States mobilize for the largest military endeavor in the nation’s history. Dumenil shows how women activists staked their claim to loyal citizenship by framing their war work as homefront volunteers, overseas nurses, factory laborers, and support personnel as “the second line of defense.” But in assessing the impact of these contributions on traditional gender roles, Dumenil finds that portrayals of these new modern women did not always match with real and enduring change. Extensively researched and drawing upon popular culture sources as well as archival material, The Second Line of Defense offers a comprehensive study of American women and war and frames them in the broader context of the social, cultural, and political history of the era.
Out of the Egg
Authors: Knapp Krister Dylan
Published: September 2017

Chapter three charts James's contributions to the Society for Psychical Research and the American Society for Psychical Research a researcher, investigator, officer, committee chairman, financial supporter, and cheerleader.
The Unseen World
Authors: Knapp Krister Dylan
Published: September 2017

Chapter seven concentrates on James's theory of immortality, focusing on his explanation of the supposed communications from the dead. It establishes that his study of trance states in Spiritualist mediums led him to formulate the sublime cosmic reservoir theory, or the view that upon bodily death consciousness melds organically with all previous consciousness and is stored over time in the cosmos, which James called the “mother sea of consciousness.”
Sex and the Civil War
Authors: Giesberg Judith
Published: September 2017

Civil War soldiers enjoyed unprecedented access to obscene materials of all sorts, including mass-produced erotic fiction, carte de visite, playing cards, and stereographs. With a series of antebellum legal, technological, and commercial developments as a foundation, the concentration of men into armies ushered in a wartime triumph of pornography. Illicit materials entered camps in haversacks, through the mail, or sold by sutlers; soldiers found it discarded on the ground and civilians discovered it in abandoned camps. Little of it survived the war, though, as soldiers did not keep it and archives did not collect it. Even so, porn raised concerns among reformers and lawmakers who launched a postwar campaign to combat it. At the war’s end, a victorious, resurgent nation-state sought to assert its moral authority by redefining human relations of the most intimate sort, including the regulation of sex and reproduction, most evident in the Comstock Laws, a federal law and a series of state measures outlawing pornography, contraception, and abortion. Sex and the Civil War is the first book to take the erotica and pornography that men read and shared seriously and to link the postwar reaction to porn to debates about the future of sex and marriage.
True Courage
Authors: Giesberg Judith
Published: September 2017

Although Antony Comstock joined the Seventeenth Connecticut late in the war and never saw combat, he did not remember it that way. Instead, he told stories about his bravery and narrow escapes from death that were really about his anti-pornography campaign. In Comstock’s mind the two wars, the Civil War (the one he never fought in, the one that nearly defeated him) and the war against porn (the one from which he emerged bruised and scarred but nonetheless victorious), remained forever conflated. We remember him for the latter one, but to understand Comstock’s life-long obsession with saving men and boys from their erotic imaginations, we have to understand how the crusader surrendered to his own imagination in the Civil War.
Outraged Manhood of Our Age
Authors: Giesberg Judith
Published: September 2017

In February 1865, Congress passed the first ever federal antipornography law as a war measure intended to preserve the morality and secure the fighting strength of men serving in the U.S. Army. But the measure also marked the beginning of a postwar surge of legislation protecting morality and marriage and resurrecting a gender order that congressmen believed the war had upset. The Young Men’s Christian Association (YMCA) and Anthony Comstock lobbied successfully for a follow up measure that became known as the Comstock Law (1873). This law extended the wartime concern for endangered manhood into a series of measures aimed at pornography and restricting women’s access to birth control and abortion. These latter laws remained in place for decades. The instinct to regulate American morality by controlling women’s sexual expression became one of the U.S. Civil War’s longest cultural legacies.
Latino Migration and the Ruins of Industrial America
Authors: Barber Llana
Published: September 2017

To feel like you belong to a city and to feel intimately linked to its roots, it is not enough to just reside in a city. To accept a city as your own, you have to have lived, worked, suffered, and forged the history of that city....
The Armpit of the Northeast?
Authors: Barber Llana
Published: September 2017

Chapter Six recounts the decimation of Lawrence's public services in the 1980s and 1990s, with an emphasis on public safety and education. Major metropolitan centers experienced a "tale of two cities" phenomenon in this era (substantial reinvestment in some neighborhoods along with deepening crisis in others); in smaller postindustrial cities, however, economic decline often continued to define the city as a whole. Lawrence's crisis is situated in the larger battles over public spending in the late twentieth century, especially state-level education and welfare reform legislation. These reform efforts illustrate a distinctly suburban political agenda that came to reject the liberal welfare state when many voters saw it as privileging poor, urban communities of color.
Creating the Latino City
Authors: Barber Llana
Published: September 2017

Chapter Seven traces Lawrence's transition to a Latino-majority city with the 2000 census, including the tremendous increase in immigration during the 1980s that led Lawrence to become home to the largest concentration of Dominicans in the United States outside of New York City. The city's Latino population came to define Lawrence's public culture in this period, and the long push for Latino political power in the city was ultimately successful in many ways. This chapter discusses the transnational activities that brought new vitality to Lawrence's economy and its public spaces, yet larger structural forces continued to create obstacles to Latinos finding in Lawrence the better life they pursued.
Introduction
Authors: Stern Jessica Yirush
Published: September 2017

The introduction explains the methods (derived mostly from anthropology) that the author will use to explain production, gift exchange, commodity exchange, and consumption in the colonial Southeast. It describes the social and cultural changes occurring in Southeastern Indian communities and British communities on the eve of contact.
General Pickens, Indian Treaty Commissioner
Authors: Andrew Rod
Published: September 2017

This chapter begins with Pickens’s rapid transformation from a renowned Indian fighter to a peacemaker. South Carolina state leaders entrust Pickens with the conduct of diplomacy with the Cherokees and with the Creeks, specifically Creek leader Alexander McGillivray. In 1785 he is appointed as a federal treaty commissioner and plays an important role in concluding the Hopewell treaties with the Cherokee, Choctaw, and Chickasaw Indians at his Hopewell property in December 1785 and January 1786. These treaties are the first ones between the new United States and the Indian tribes south of the Ohio River. The chapter stresses the tension between men like Pickens and Benjamin Hawkins who hoped the federal government could negotiate permanent and just agreements with the Indians and other whites and state leaders who resented the federal government’s role and were anxious to take over more Indian land.
Introduction
Authors: Brazinsky Gregg A.
Published: September 2017

The purpose of the introduction is to explain my general argument and review the historiography on my topic. The first part of the introduction describes briefly how the book fits into the evolving paradigm of Cold War studies and how looking at Sino-American competition in the Third World broadens our understanding of the field. The second part explores the concept of status, especially as it applies to Chinese and American foreign relations during the Cold War.
The Cultural Competition, 1955–1964
Authors: Brazinsky Gregg A.
Published: September 2017

Alongside Beijing’s diplomatic campaign to win over Afro-Asian countries went an equally vigorous cultural initiative. During the 1950s and early 1960s the PRC carried out a multi-faceted propaganda offensive that highlighted China’s economic and military achievements while criticizing American imperialism. The overarching goal was to reassure the world about China’s intentions while inspiring admiration for the CCP’s revolutionary struggle. This chapter also covers Washington’s efforts to counter the effects of the PRC’s cultural diplomacy.
Insurgency and Counterinsurgency, 1961–1968
Authors: Brazinsky Gregg A.
Published: September 2017

Even as the PRC sought to win over radical and neutralist Afro-Asian states through diplomacy, it also sought to gain prestige in the Third World by becoming a leader of revolutionary forces. The PRC befriended a diverse group of Afro-Asian and insurgents guerilla that espoused Maoist doctrines during the 1960s. They believed that doing so would help to spread Mao Zedong thought throughout the world, raising the status of both the PRC and its leader. America’s fear that insurgent victories in countries such as Vietnam, Thailand and the Congo would enhance Chinese prestige and legitimate Maoism played a key role in precipitating some of the most dramatic and costly instances of U.S. intervention of the Cold War.
Competition and Cooperation, 1968–1979
Authors: Brazinsky Gregg A.
Published: September 2017

This chapter traces the evolution of Sino-American competition in the Third World during the era of détente. Although some forms of competition between Beijing and Washington in the Third World persisted, the changing relationship also made it possible for limited forms of cooperation to occur. By the late 1970s, tentative forms of cooperation that occurred during the Nixon and Ford administrations evolved into more extensive collaboration in Afghanistan and elsewhere.
Women's Antiwar Diplomacy during the Vietnam War Era
Authors: Frazier Jessica M.
Published: September 2017

In 1965, fed up with President Johnson’s refusal to make serious diplomatic efforts to end the Vietnam War, a group of female American peace activists decided to take matters into their own hands by meeting with Vietnamese women to discuss how to end U.S. intervention. While other attempts at women’s international cooperation and transnational feminism have led to cultural imperialism or imposition of American ways on others, Jessica Frazier reveals an instance when American women crossed geopolitical boundaries to criticize American Cold War culture, not promote it. The American women Frazier studies not only solicited Vietnamese women’s opinions and advice on how to end the war, but also viewed them as paragons of a new womanhood by which American women could rework their ideas of gender, revolution, and social justice during an era of reinvigorated feminist agitation. Unlike the many histories of the Vietnam War that end with an explanation of why the memory of the war still divides U.S. society, by focusing on linkages across national boundaries, Frazier illuminates a significant moment in history when women formed effective transnational relationships on genuinely cooperative terms.
Establishing Feminist Perspectives on War, 1969–1972
Authors: Frazier Jessica M.
Published: September 2017

Conflict before, during, and after the Indochinese Women’s Conferences (IWC) in Canada in 1971 forced women's liberationists invested in hosting the IWC to contemplate why war was an important feminist issue. Before the conference even began, white women's liberationists debated the relationship between sexism and imperialism and fostered a rethinking of war's relationship to women and society. Much of the literature on second-wave feminism overlooks the international context, but I argue that the circumstances of the Viet Nam war generated feminist perspectives on military actions.
From Goodwill to Grunge
Authors: Le Zotte Jennifer
Published: September 2017

In this surprising new look at how clothing, style, and commerce came together to change American culture, Jennifer Le Zotte examines how secondhand goods sold at thrift stores, flea markets, and garage sales came to be both profitable and culturally influential. Initially, selling used goods in the United States was seen as a questionable enterprise focused largely on the poor. But as the twentieth century progressed, multimillion-dollar businesses like Goodwill Industries developed, catering not only to the needy but increasingly to well-off customers looking to make a statement. Le Zotte traces the origins and meanings of “secondhand style” and explores how buying pre-owned goods went from a signifier of poverty to a declaration of rebellion.
Considering buyers and sellers from across the political and economic spectrum, Le Zotte shows how conservative and progressive social activists--from religious and business leaders to anti-Vietnam protesters and drag queens--shrewdly used the exchange of secondhand goods for economic and political ends. At the same time, artists and performers, from Marcel Duchamp and Fanny Brice to Janis Joplin and Kurt Cobain, all helped make secondhand style a visual marker for youth in revolt.
Making Gullah
Authors: Cooper Melissa L.
Published: September 2017

During the 1920s and 1930s, anthropologists and folklorists became obsessed with uncovering connections between African Americans and their African roots. At the same time, popular print media and artistic productions tapped the new appeal of black folk life, highlighting African-styled voodoo as an essential element of black folk culture. A number of researchers converged on one site in particular, Sapelo Island, Georgia, to seek support for their theories about “African survivals,” bringing with them a curious mix of both influences. The legacy of that body of research is the area’s contemporary identification as a Gullah community.
This wide-ranging history upends a long tradition of scrutinizing the Low Country blacks of Sapelo Island by refocusing the observational lens on those who studied them. Cooper uses a wide variety of sources to unmask the connections between the rise of the social sciences, the voodoo craze during the interwar years, the black studies movement, and black land loss and land struggles in coastal black communities in the Low Country. What emerges is a fascinating examination of Gullah people's heritage, and how it was reimagined and transformed to serve vastly divergent ends over the decades.
Variations in Tape Use and the Position of the Narrator
Authors: Spiegel Alix
Published: September 2017

Alix Spiegel, long a producer and reporter with This American Life and NPR News, teamed up with Lulu Miller to create Invisibilia. In another of our new essays, Alix writes frankly about Invisibilia’s debt to This American Life and to Lulu’s former employer, Radiolab. But with their deep reporting and storytelling flair, Alix and Lulu—along with third host Hanna Rosin, editor Anne Gudenkauf, and the rest of their team—give Invisibilia a feel and flavor all its own. The show’s mix of learning and entertainment has quickly drawn a legion of devoted fans.
No Holes Were Drilled in the Heads of Animals in the Making of This Radio Show
Authors: Abumrad Jad
Published: September 2017

Radiolab, from WNYC, has stuff to tell you, too, but goes further than any other show in combining information with virtuosic invention. With co-host and radio legend Robert Krulwich, producer Jad Abumrad takes listeners on sonic adventures into big questions: What is morality? How do the mind and body talk to one another? Why do we sleep? Through an annotated transcript, Jad reveals his kitchen-sink approach to radio making. Take interviews and recorded sounds; stir in sound effects, music, elements of radio drama and sonic surprises; and infuse it all with a sense of intelligent wonder.
Brominated VSLS and their influence on ozone under a changing climate
Authors: Falk Stefanie , Sinnhuber Björn-Martin , Krysztofiak Gisèle , Jöckel Patrick , Graf Phoebe , Lennartz Sinikka T.
Published: September 2017

Abstract. Very short-lived substances (VSLS) contribute as source gases significantly to the tropospheric and stratospheric bromine loading. At present, an estimated 25 % of stratospheric bromine is of oceanic origin. In this study, we investigate how climate change may impact the ocean–atmosphere flux of brominated VSLS, their atmospheric transport, and chemical transformations and evaluate how these changes will affect stratospheric ozone over the 21st century. Under the assumption of fixed ocean water concentrations and RCP6.0 scenario, we find an increase of the ocean–atmosphere flux of brominated VSLS of about 8–10 % by the end of the 21st century compared to present day. A decrease in the tropospheric mixing ratios of VSLS and an increase in the lower stratosphere are attributed to changes in atmospheric chemistry and transport. Our model simulations reveal that this increase is counteracted by a corresponding reduction of inorganic bromine. Therefore the total amount of bromine from VSLS in the stratosphere will not be changed by an increase in upwelling. Part of the increase of VSLS in the tropical lower stratosphere results from an increase in the corresponding tropopause height. As the depletion of stratospheric ozone due to bromine depends also on the availability of chlorine, we find the impact of bromine on stratospheric ozone at the end of the 21st century reduced compared to present day. Thus, these studies highlight the different factors influencing the role of brominated VSLS in a future climate.
Effect of sea breeze circulation on aerosol mixing state and radiative properties in a desert setting
Authors: Derimian Yevgeny , Choël Marie , Rudich Yinon , Deboudt Karine , Dubovik Oleg , Laskin Alexander , Legrand Michel , Damiri Bahaiddin , Koren Ilan , Unga Florin , Moreau Myriam , Andreae Meinrat O. , Karnieli Arnon
Published: September 2017

Abstract. Chemical composition, microphysical, and optical properties of atmospheric aerosol deep inland in the Negev Desert of Israel are found to be influenced by daily occurrences of sea breeze flow from the Mediterranean Sea. Abrupt increases in aerosol volume concentration and shifts of size distributions towards larger sizes, which are associated with increase in wind speed and atmospheric water content, were systematically recorded during the summertime at a distance of at least 80 km from the coast. Chemical imaging of aerosol samples showed an increased contribution of highly hygroscopic particles during the intrusion of the sea breeze. Besides a significant fraction of marine aerosols, the amount of internally mixed marine and mineral dust particles was also increased during the sea breeze period. The number fraction of marine and internally mixed particles during the sea breeze reached up to 88 % in the PM1–2. 5 and up to 62 % in the PM2. 5–10 size range. Additionally, numerous particles with residuals of liquid coating were observed by SEM/EDX analysis. Ca-rich dust particles that had reacted with anthropogenic nitrates were evidenced by Raman microspectroscopy. The resulting hygroscopic particles can deliquesce at very low relative humidity. Our observations suggest that aerosol hygroscopic growth in the Negev Desert is induced by the daily sea breeze arrival. The varying aerosol microphysical and optical characteristics perturb the solar and thermal infrared radiations. The changes in aerosol properties induced by the sea breeze, relative to the background situation, doubled the shortwave radiative cooling at the surface (from −10 to −20.5 W m−2) and increased by almost 3 times the warming of the atmosphere (from 5 to 14 W m−2), as evaluated for a case study. Given the important value of observed liquid coating of particles, we also examined the possible influence of the particle homogeneity assumption on the retrieval of aerosol microphysical characteristics. The tests suggest that sensitivity to the coating appears if backward scattering and polarimetric measurements are available for the inversion algorithm. This may have an important implication for retrievals of aerosol microphysical properties in remote sensing applications.
The topography contribution to the influence of the atmospheric boundary layer at high altitude stations
Authors: Collaud Coen Martine , Andrews Elisabeth , Aliaga Diego , Andrade Marcos , Angelov Hristo , Bukowiecki Nicolas , Ealo Marina , Fialho Paulo , Flentje Harald , Hallar A. Gannet , Hooda Rakesh , Kalapov Ivo , Krejci Radovan , Lin Neng-Huei , Marinoni Angela , Ming Jing , Nguyen Nhat Anh , Pandolfi Marco , Pont Véronique , Ries Ludwig , Rodríguez Sergio , Schauer Gerhard , Sellegri Karine , Sharma Sangeeta , Sun Junying , Tunved Peter , Velasquez Patricio , Ruffieux Dominique
Published: September 2017

Abstract. High altitude stations are often emphasized as free tropospheric measuring sites but they remain influenced by atmospheric boundary layer (ABL) air masses due to convective transport processes. The local and meso-scale topographical features around the station are involved in the convective boundary layer development and in the formation of thermally induced winds leading to ABL air lifting. The station altitude is not a sufficient parameter to characterize the ABL influence. Topography data from the global digital elevation model GTopo30 were used to calculate 5 parameters for 46 high altitude stations situated in five continents. The geometric mean of these 5 parameters determines a topography based index called ABL-TopoIndex which can be used to rank the high altitude stations as a function of the ABL influence. To construct the ABL-TopoIndex, we rely on the criteria that the ABL influence will be low if the station is one of the highest points in the mountainous massif, if there is a large altitude difference between the station and the valleys or plateaus, if the slopes around the station are steep, and finally if the drainage basin for air convection is small. All stations on volcanic islands exhibit a low ABL-TopoIndex whereas stations in the Himalaya and the Tibetan Plateau have high ABL-TopoIndex values. Spearman's rank correlation between aerosol optical properties and number concentration from 28 stations and the ABL-TopoIndex, the altitude and the latitude are used to validate this topographical approach. Statistically significant (s.s.) correlations are found between the 5 and 50 percentiles of all aerosol parameters and the ABL-TopoIndex whereas no s.s. correlation is found with the station altitude. The diurnal cycles of aerosol parameters seem to be best explained by the station latitude although a s.s. correlation is found between the amplitude of the diurnal cycles of the absorption coefficient and the ABL-TopoIndex. Finally, the main flow paths for air convection were calculated for various ABL heights.
Sources of reactive nitrogen in marine aerosol over the Northwest Pacific Ocean in spring
Authors: Luo Li , Kao Shuh-Ji , Bao Hongyan , Xiao Huayun , Xiao Hongwei , Yao Xiaohong , Gao Huiwang , Li Jiawei , Lu Yangyang
Published: September 2017

Abstract. Abstract Atmospheric deposition of long range transport anthropogenic reactive nitrogen (Nr, mainly NHx, NOy and water-soluble organic nitrogen (WSON)) from continent exerts profound impact on marine biogeochemistry. On the other hand, marine biogenic dissolve organic nitrogen (DON) is also a potential contributor to aerosol WSON in overlying atmosphere. Despite of the importance of off-continent dispersion and interactive processes of Nr in the atmosphere–ocean boundary, knowledge regarding sources of various nitrogen species in the open ocean remained limited due to insufficient observations. In spring of 2014 and 2015, we conducted two cruises starting from the coast of China through the East China Seas (ECSs, i.e. Yellow Sea and East China Sea) to the open ocean (i.e. Northwest Pacific Ocean, NWPO). Concentrations of water-soluble total nitrogen (WSTN), NO3− and NH4+, and δ15N of WSTN and NO3− in marine aerosol were measured for both cruises. In spring of 2015, we also analysed the aerosol CHON molecular formulas by using Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS), and the concentrations and δ15N of NO3− and DON of surface sea water (SSW) (depth 5 m) along the cruise track. Aerosol NO3−, NH4+ and WSON showed a logarithmic off shore decrease pattern (1–2 orders of magnitude drop) reflecting a strong anthropogenic emission source of NO3−, NH4+ and WSON from China. Concentrations of aerosol NO3− and NH4+ were significantly higher in 2014 (even in remote NWOP) than those in 2015 due to stronger wind field in 2014, underscoring the role of the Asian winter monsoon in seaward transport of anthropogenic NO3− and NH4+. However, the WSON in background aerosol over the NWPO in 2015 (12.7 ± 8.7 nmol m−3) was close to that in 2014 (10.7 ± 7.0 nmol m−3) suggesting an addition of non-anthropogenic WSON source in the open ocean. Results of the FT-ICR-MS analyses revealed a higher contribution of marine biological source to WSON in background aerosol and this was supported by the analysis of isotopic mixing between aerosol NH4+ and SSW DON (5.8 ± 2.0 ‰). Obviously, the marine DON emission should be considered in model and field work while assessing the net atmospheric WSON deposition in the open ocean. This is the first hand parallel dataset for isotopic compositions of marine DON and aerosol Nr, more studies are required to explore the complicated processes of sources and deposition of Nr to advance our knowledge of the anthropogenic influence on marine nitrogen cycle and nitrogen exchanges through the land–ocean and the air–sea interface.
Uncertainty of the global oceanic CO2 uptake induced by wind forcing: quantification and spatial analysis
Authors: Roobaert Alizée , Laruelle Goulven G. , Landschützer Peter , Regnier Pierre
Published: September 2017

Abstract. Abstract. The calculation of the air-water CO2 exchange (FCO2) in the ocean not only depends on the gradient in CO2 partial pressure at the air-water interface but also on the parameterization of the gas exchange transfer velocity (k) and the choice of wind product. Here, we present regional and global-scale quantifications of the uncertainty in FCO2 induced by several widely used k-formulations and 4 wind speed data products (CCMP, ERA, NCEP1 and NCEP2). The analysis is performed at a 1° x 1° resolution using the sea surface pCO2 climatology generated by Landschützer et al. (2015) for the 1991–2011 period while the regional assessment relies on the segmentation proposed by the Regional Carbon Cycle Assessment and Processes (RECCAP) project. First, we use k-formulations derived from the global 14C inventory relying on a quadratic relationship between k and wind speed (k = c·U102, Sweeney et al., 2007; Takahashi et al., 2009; Wanninkhof, 2014) where c is a calibration coefficient and U10 is the wind speed measured 10 meters above the surface. Our results show that the range of global FCO2, calculated with these k-relationships, diverge by 12 % when using CCMP, ERA or NCEP1. Due to differences in the regional wind patterns, regional discrepancies in FCO2 are more pronounced than global. These global/regional differences significantly increase when using NCEP2 or other k-formulations which include earlier relationships (i.e. Wanninkhof, 1992; Wanninkhof et al., 2009) as well as numerous local/regional parameterizations derived experimentally. To minimize uncertainties associated with the choice of wind product it is possible to recalculate the coefficient c globally (hereafter called c*) for a given wind product and its spatio-temporal resolution, in order to match the last evaluation of the global k value. We thus performed these recalculations for each wind product at the resolution and time period of our study but the resulting global FCO2 estimates still diverge by 10 %. These results also reveal that the Equatorial Pacific, the North Atlantic and the Southern Ocean are the regions in which the choice of wind product will most strongly affect the estimation of the FCO2, even when using c*.
Revisiting chlorophyll extraction methods in biological soil crusts – methodology for determination of chlorophyll a and chlorophyll a + b as compared to previous methods
Authors: Caesar Jennifer , Tamm Alexandra , Ruckteschler Nina , Weber Bettina
Published: September 2017

Abstract. Chlorophyll concentrations of biological soil crust (biocrust) samples are commonly determined to quantify the relevance of photosynthetically active organisms within these surface soil communities. Whereas chlorophyll extraction methods for freshwater algae and leaf tissues of vascular plants are well established, there is still some uncertainty regarding the optimal extraction method for biocrusts, where organism composition is highly variable and samples comprise major amounts of soil. In this study we analyzed the efficiency of two different chlorophyll extraction solvents, the effect of grinding the soil samples prior to the extraction procedure and the impact of shaking as an intermediate step during extraction. The analyses were conducted on four different types of biocrusts. Our results show, that for all biocrust types chlorophyll contents obtained with ethanol were significantly lower than those obtained with dimethyl sulfoxide (DMSO) as solvent. Grinding of biocrust samples prior to analysis caused a highly significant decrease in chlorophyll content for green algal lichen- and cyanolichen-dominated biocrusts, and a tendency towards lower values for moss- and algae-dominated biocrusts. Shaking of the samples after each extraction step had a significant positive effect on the chlorophyll content of green algal lichen- and cyanolichen-dominated biocrusts. Based on our results we confirm a DMSO-based chlorophyll extraction method without grinding pretreatment and suggest to insert an intermediate shaking step for complete chlorophyll extraction (see supplement S6 for detailed manual). Determination of a universal chlorophyll extraction method for biocrusts is essential for the inter-comparability of studies conducted across all continents.
The influence of ice sheets on temperature during the past 38 million years inferred from a one-dimensional ice sheet–climate model
Authors: Stap Lennert B. , van de Wal Roderik S. W. , de Boer Bas , Bintanja Richard , Lourens Lucas J.
Published: September 2017

Abstract. Since the inception of the Antarctic ice sheet at the Eocene–Oligocene transition (∼ 34 Myr ago), land ice has played a crucial role in Earth's climate. Through feedbacks in the climate system, land ice variability modifies atmospheric temperature changes induced by orbital, topographical, and greenhouse gas variations. Quantification of these feedbacks on long timescales has hitherto scarcely been undertaken. In this study, we use a zonally averaged energy balance climate model bidirectionally coupled to a one-dimensional ice sheet model, capturing the ice–albedo and surface–height–temperature feedbacks. Potentially important transient changes in topographic boundary conditions by tectonics and erosion are not taken into account but are briefly discussed. The relative simplicity of the coupled model allows us to perform integrations over the past 38 Myr in a fully transient fashion using a benthic oxygen isotope record as forcing to inversely simulate CO2. Firstly, we find that the results of the simulations over the past 5 Myr are dependent on whether the model run is started at 5 or 38 Myr ago. This is because the relation between CO2 and temperature is subject to hysteresis. When the climate cools from very high CO2 levels, as in the longer transient 38 Myr run, temperatures in the lower CO2 range of the past 5 Myr are higher than when the climate is initialised at low temperatures. Consequently, the modelled CO2 concentrations depend on the initial state. Taking the realistic warm initialisation into account, we come to a best estimate of CO2, temperature, ice-volume-equivalent sea level, and benthic δ18O over the past 38 Myr. Secondly, we study the influence of ice sheets on the evolution of global temperature and polar amplification by comparing runs with ice sheet–climate interaction switched on and off. By passing only albedo or surface height changes to the climate model, we can distinguish the separate effects of the ice–albedo and surface–height–temperature feedbacks. We find that ice volume variability has a strong enhancing effect on atmospheric temperature changes, particularly in the regions where the ice sheets are located. As a result, polar amplification in the Northern Hemisphere decreases towards warmer climates as there is little land ice left to melt. Conversely, decay of the Antarctic ice sheet increases polar amplification in the Southern Hemisphere in the high-CO2 regime. Our results also show that in cooler climates than the pre-industrial, the ice–albedo feedback predominates the surface–height–temperature feedback, while in warmer climates they are more equal in strength.
The Plio-Pleistocene climatic evolution as a consequence of orbital forcing on the carbon cycle
Authors: Paillard Didier
Published: September 2017

Abstract. Since the discovery of ice ages in the 19th century, a central question of climate science has been to understand the respective role of the astronomical forcing and of greenhouse gases, in particular changes in the atmospheric concentration of carbon dioxide. Glacial–interglacial cycles have been shown to be paced by the astronomy with a dominant periodicity of 100 ka over the last million years, and a periodicity of 41 ka between roughly 1 and 3 million years before present (Myr BP). But the role and dynamics of the carbon cycle over the last 4 million years remain poorly understood. In particular, the transition into the Pleistocene about 2.8 Myr BP or the transition towards larger glaciations about 0.8 Myr BP (sometimes referred to as the mid-Pleistocene transition, or MPT) are not easily explained as direct consequences of the astronomical forcing. Some recent atmospheric CO2 reconstructions suggest slightly higher pCO2 levels before 1 Myr BP and a slow decrease over the last few million years (Bartoli et al., 2011; Seki et al., 2010). But the dynamics and the climatic role of the carbon cycle during the Plio-Pleistocene period remain unclear. Interestingly, the δ13C marine records provide some critical information on the evolution of sources and sinks of carbon. In particular, a clear 400 kyr oscillation has been found at many different time periods and appears to be a robust feature of the carbon cycle throughout at least the last 100 Myr (e.g. Paillard and Donnadieu, 2014). This oscillation is also visible over the last 4 Myr but its relationship with the eccentricity appears less obvious, with the occurrence of longer cycles at the end of the record, and a periodicity which therefore appears shifted towards 500 kyr (see Wang et al., 2004). In the following we present a simple dynamical model that provides an explanation for these carbon cycle variations, and how they relate to the climatic evolution over the last 4 Myr. It also gives an explanation for the lowest pCO2 values observed in the Antarctic ice core around 600–700 kyr BP. More generally, the model predicts a two-step decrease in pCO2 levels associated with the 2.4 Myr modulation of the eccentricity forcing. These two steps occur respectively at the Plio-Pleistocene transition and at the MPT, which strongly suggests that these transitions are astronomically forced through the dynamics of the carbon cycle.
Several years of experience with automatic DI-flux systems: theory, validation and results
Authors: Poncelet Antoine , Gonsette Alexandre , Rasson Jean
Published: September 2017

Abstract. The previous release of our automatic DI-flux instrument, called AutoDIF mk2.2, has now been running continuously since June 2012 in the absolute house of Dourbes magnetic observatory performing measurement every 30 min. A second one has been working in the tunnel of Conrad observatory (Austria) since December 2013. After this proof of concept, we improved the AutoDIF to version mk2.3, which was presented at the 16th IAGA workshop in Hyderabad. As of publication, we have successfully deployed six AutoDIFs in various environments: two in Dourbes (DOU), one in Manhay (MAB), one in Conrad (CON), one in Daejeon (South Korea) and one is used for tests. The latter was installed for 10 months in Chambon-la-Forêt (CLF) and, since 2016, has been in Kakioka (KAK). In this paper, we will compare the automatic to the human-made measurements and discuss the advantages and disadvantages of automatic measurements.
Reverse engineering model structures for soil and ecosystem respiration: the potential of gene expression programming
Authors: Ilie Iulia , Dittrich Peter , Carvalhais Nuno , Jung Martin , Heinemeyer Andreas , Migliavacca Mirco , Morison James I. L. , Sippel Sebastian , Subke Jens-Arne , Wilkinson Matthew , Mahecha Miguel D.
Published: September 2017

Abstract. Accurate model representation of land–atmosphere carbon fluxes is essential for climate projections. However, the exact responses of carbon cycle processes to climatic drivers often remain uncertain. Presently, knowledge derived from experiments, complemented by a steadily evolving body of mechanistic theory, provides the main basis for developing such models. The strongly increasing availability of measurements may facilitate new ways of identifying suitable model structures using machine learning. Here, we explore the potential of gene expression programming (GEP) to derive relevant model formulations based solely on the signals present in data by automatically applying various mathematical transformations to potential predictors and repeatedly evolving the resulting model structures. In contrast to most other machine learning regression techniques, the GEP approach generates readable models that allow for prediction and possibly for interpretation. Our study is based on two cases: artificially generated data and real observations. Simulations based on artificial data show that GEP is successful in identifying prescribed functions, with the prediction capacity of the models comparable to four state-of-the-art machine learning methods (random forests, support vector machines, artificial neural networks, and kernel ridge regressions). Based on real observations we explore the responses of the different components of terrestrial respiration at an oak forest in south-eastern England. We find that the GEP-retrieved models are often better in prediction than some established respiration models. Based on their structures, we find previously unconsidered exponential dependencies of respiration on seasonal ecosystem carbon assimilation and water dynamics. We noticed that the GEP models are only partly portable across respiration components, the identification of a general terrestrial respiration model possibly prevented by equifinality issues. Overall, GEP is a promising tool for uncovering new model structures for terrestrial ecology in the data-rich era, complementing more traditional modelling approaches.
Effects of sample size on estimation of rainfall extremes at high temperatures
Authors: Boessenkool Berry , Bürger Gerd , Heistermann Maik
Published: September 2017

Abstract. High precipitation quantiles tend to rise with temperature, following the so-called Clausius–Clapeyron (CC) scaling. It is often reported that the CC-scaling relation breaks down and even reverts for very high temperatures. In our study, we investigate this reversal using observational climate data from 142 stations across Germany. One of the suggested meteorological explanations for the breakdown is limited moisture supply. Here we argue that, instead, it could simply originate from undersampling. As rainfall frequency generally decreases with higher temperatures, rainfall intensities as dictated by CC scaling are less likely to be recorded than for moderate temperatures. Empirical quantiles are conventionally estimated from order statistics via various forms of plotting position formulas. They have in common that their largest representable return period is given by the sample size. In small samples, high quantiles are underestimated accordingly. The small-sample effect is weaker, or disappears completely, when using parametric quantile estimates from a generalized Pareto distribution (GPD) fitted with L moments. For those, we obtain quantiles of rainfall intensities that continue to rise with temperature.
MobRISK: a model for assessing the exposure of road users to flash flood events
Authors: Shabou Saif , Ruin Isabelle , Lutoff Céline , Debionne Samuel , Anquetin Sandrine , Creutin Jean-Dominique , Beaufils Xavier
Published: September 2017

Abstract. Recent flash flood impact studies highlight that road networks are often disrupted due to adverse weather and flash flood events. Road users are thus particularly exposed to road flooding during their daily mobility. Previous exposure studies, however, do not take into consideration population mobility. Recent advances in transportation research provide an appropriate framework for simulating individual travel-activity patterns using an activity-based approach. These activity-based mobility models enable the prediction of the sequence of activities performed by individuals and locating them with a high spatial–temporal resolution. This paper describes the development of the MobRISK microsimulation system: a model for assessing the exposure of road users to extreme hydrometeorological events. MobRISK aims at providing an accurate spatiotemporal exposure assessment by integrating travel-activity behaviors and mobility adaptation with respect to weather disruptions. The model is applied in a flash-flood-prone area in southern France to assess motorists' exposure to the September 2002 flash flood event. The results show that risk of flooding mainly occurs in principal road links with considerable traffic load. However, a lag time between the timing of the road submersion and persons crossing these roads contributes to reducing the potential vehicle-related fatal accidents. It is also found that sociodemographic variables have a significant effect on individual exposure. Thus, the proposed model demonstrates the benefits of considering spatiotemporal dynamics of population exposure to flash floods and presents an important improvement in exposure assessment methods. Such improved characterization of road user exposures can present valuable information for flood risk management services.
Derivation of the entropic formula for the statistical mechanics of space plasmas
Authors: Livadiotis George
Published: September 2017

Abstract. Kappa distributions describe velocities and energies of plasma populations in space plasmas. The statistical origin of these distributions is the non-extensive statistical mechanics. Indeed, the kappa distribution is derived by maximizing the q-entropy of Tsallis under the constraints of canonical ensemble. However, there remains the question what is the physical origin of this entropic formulation. This paper shows that the q-entropy can be derived by adapting the additivity of energy and entropy.
Interannual evolution of (sub)mesoscale dynamics in the Bay of Biscay
Authors: Charria Guillaume , Theetten Sébastien , Vandermeirsch Frédéric , Yelekçi Özge , Audiffren Nicole
Published: September 2017

Abstract. In the north-east Atlantic Ocean, the Bay of Biscay is an intersection between a coastal constrained dynamics (wide continental shelf and shelf break regions) and an eastern boundary circulation system. In this framework, the eddy kinetic energy is 1 order of magnitude lower than in western boundary systems. To explore this coastal complex system, a high-resolution (1 km, 100 vertical sigma layers) model experiment including tidal dynamics over a period of 10 years (2001–2010) has been implemented. The ability of the numerical environment to reproduce main patterns over interannual scales is demonstrated. Based on this experiment, the features of the (sub)mesoscale processes are described in the deep part of the region (i.e. abyssal plain and continental slope). A system with the development of mixed layer instabilities at the end of winter is highlighted. Beyond confirming an observed behaviour of seasonal (sub)mesoscale activity in other regions, the simulated period allows exploring the interannual variability of these structures. A relationship between the winter maximum of mixed layer depth and the intensity of (sub)mesoscale related activity (vertical velocity, relative vorticity) is revealed and can be explained by large-scale atmospheric forcings (e.g. the cold winter in 2005). The first submesoscale-permitting exploration of this 3-D coastal system shows the importance of (sub)mesoscale activity in this region with its evolution implying a potentially significant impact on vertical and horizontal mixing.
Non-linear retreat of Jakobshavn Isbræ since the Little Ice Age controlled by geometry
Authors: Steiger Nadine , Nisancioglu Kerim H. , Åkesson Henning , de Fleurian Basile , Nick Faezeh M.
Published: September 2017

Abstract. Rapid acceleration and retreat of Greenland's marine-terminating glaciers during the last two decades have initiated questions on the trigger and processes governing observed changes. Destabilization of these glaciers coincides with atmosphere and ocean warming, which broadly has been used to explain the rapid changes. To assess the relative role of external forcing versus fjord geometry, we investigate the retreat of Jakobshavn Isbræ in West Greenland, where margin positions exist since the Little Ice Age maximum in 1850. We use a one-dimensional ice flow model and isolate geometric effects on the retreat using a linear increase in external forcing. We find that the observed retreat of 43 km from 1850 until 2014 can only be simulated when multiple forcing parameters – such as hydrofracturing, submarine melt and frontal buttressing by sea ice – are changed simultaneously. Surface mass balance, in contrast, has a negligible effect. While changing external forcing initiates retreat, fjord geometry controls the retreat pattern. Basal and lateral topography govern shifts from temporary stabilization to rapid retreat, resulting in a highly non-linear glacier response. For example, we simulate a disintegration of a 15 km long floating tongue within one model year, which dislodges the grounding line onto the next pinning point. The retreat pattern loses complexity and becomes linear when we artificially straighten the glacier walls and bed, confirming the topographic controls. For real complex fjord systems such as Jakobshavn Isbræ, geometric pinning points predetermine grounding line stabilization and may therefore be used as a proxy for moraine build-up. Also, we find that after decades of stability and with constant external forcing, grounding lines may retreat rapidly without any trigger. This means that past changes may precondition marine-terminating glaciers to reach tipping-points, and that retreat can occur without additional climate warming. Present-day changes and future projections can therefore not be viewed in isolation of historic retreat.