bluuebunny/crossref_metadata_2025 huggingface dataset:
The Interface between Childcare, Family Support and Child Poverty Strategies Under New Labour: Tensions and Contradictions
Authors: Lloyd Eva
Published: September 2008

New Labour's national childcare and family support strategies have been aimed at improving mothers' labour market participation and children's future educational achievements. As such, they constitute a key component of the child poverty agenda. HM Treasury has assumed a pivotal role in furthering the strategies' objectives. This article explores whether the mixed market economy selected as the vehicle to deliver childcare and family support provision, promotes separate markets for the poor and the better off, while hindering the achievement of child poverty strategy outcomes.
From Being to Becoming: The Importance of Tackling Youth Poverty in Transitions To Adulthood
Authors: France Alan
Published: September 2008

The central emphasis of New Labour's anti-poverty strategy has been on tackling child poverty. While such an approach is both important and valuable youth poverty has been given limited attention. Low and unstable incomes are a major cause of poverty amongst young people and risks are greatly increased as they try to live independently and move out of the family home. In the discussion that follows, I argue that New Labour's continued commitment to the social exclusion agenda has marginalised both the problem of youth poverty and the necessary solutions. Social exclusion policy is more concerned with responsiblising families and young people and disciplining them to work regardless of its value. Little attention is given to addressing the problems of youth incomes or providing adequate housing support for those most vulnerable to poverty.
Tackling Child Poverty Dynamics: Filling in Gaps in the Strategy
Authors: Smith Noel
Published: September 2008

Since announcing its ambitious pledge to eradicate child poverty, the Government's strategy has focused on providing extra income to families, particularly in terms of tax credits, and on increasing employment rates among parents. Recently, however, its strategy has developed to encompass a new emphasis on job retention, career progression and smoothing movement into and out of work, all of which should serve to safeguard and support children's movement out of poverty. With reference to poverty dynamics research, this article discusses why this new emphasis is crucial for reducing child poverty and highlights the possible future direction of developing policy in this light.
Does Child Income Poverty Measure Child Well-Being Internationally?
Authors: Bradshaw Jonathan , Richardson Dominic
Published: September 2008

To date the main indicator used to compare the well-being of children in industrialised countries has been the proportion of children in income poverty. This article exploits data from recent work developing indices of child well-being in EU, OECD and CEE/CIS countries to explore whether child income poverty is a good representation of a wider understanding of child well-being. Using the poverty estimates in each index, as well as more recent estimates for the European Union, we find that for OECD countries income poverty still has some explanatory power but this is not the case for EU and CEE/CIS countries.
The State of Play: Disadvantage, Play and Children's Well-Being
Authors: Sutton Liz
Published: September 2008

There is little research that explicitly compares the lives of children from different social backgrounds, particularly with regard to their freedom, safety, and use of public space. Drawing on the findings of a participatory research project with 42 children from different socio-economic backgrounds, this article shows how and why children's play differs depending on their social background. It also highlights the importance of street play in the lives of disadvantaged children, arguing that they engage in street play as a consequence of having less space and fewer alternatives, and yet their opportunities for play are further restricted due to local development and community ‘policing’. The article calls for the safeguarding of open public space, and an increased recognition of the importance and value of street play. Finally, it points out the contradictions in government policy regarding children's play and well-being.
Ethnicity and Child Poverty under New Labour: A Research Review
Authors: Phung Viet-Hai
Published: September 2008

This review article explores the evidence on child poverty rates amongst different ethnic groups in the UK. The Labour Government aims to end child poverty by 2020. Its strategy rests on improving employability, making work pay and expanding childcare provision. But child poverty rates among ethnic minorities are higher than among white people, which suggests that policies to reduce these have been ineffectual. The factors underlying this differential include labour market disadvantage, insensitive mainstream services and the language barriers that may cause low take-up of services, benefits and tax credits. The article concludes by suggesting a number of policy strategies that government could take to reduce the levels of child poverty amongst ethnic minorities.
Some Useful Sources
Authors: Davis Abigail , Sandu Adriana
Published: September 2008

In addition to the references cited in each article, below are some other sources relevant to the topics covered by the preceding articles. Although most refer to domestic policy measures, a few offer a more comparative, international perspective. This is not intended to be a comprehensive list, rather a selection of material from a range of sources aiming to provide additional breadth and depth for those interested in child poverty and policy.
Pensions, fertility, and education
Authors: MEIER VOLKER , WREDE MATTHIAS
Published: September 2008

A pay-as-you-go pension scheme is associated with positive externalities of having children and providing them with human capital. In a framework with heterogeneity in productivity, and stochastic and endogenous investment in fertility and education, we discuss internalization policies associated with child benefits in the pension formula. The second-best scheme displays both a benefit contingent on the contributions of children and a purely fertility-related component.
Recent changes in varietal diversity of rice in Guinea
Authors: Barry M. B. , Diagne A. , Sogbossi M. J. , Pham J. L. , Diawara S. , Ahmadi N.
Published: September 2008

Rice varietal diversity was assessed in Guinea on the basis of surveys of 1679 farms located in 79 villages of the four natural regions of the country. The descriptors used were the number of known varieties, the number of cultivated varieties and Shannon's diversity and evenness index. On the basis of their use rates, varieties were classified as major or minor types at the village scale and as regionally and/or nationally eminent varieties at these scales. Varietal diversity was high, especially in forest Guinea and lower Guinea. Diversity pattern was typical of the subsistence farming system. The high share of local variety reflected the predominance of low management and low input cropping systems. The presence of improved varieties confirms farmers' openness to innovation and to the government policy of promoting improved varieties. Regional diversity reflected the agro-ecological diversity and specificities of each region, the history and the extent of rice-growing systems, and the importance of rice in the local diet. Recent dissemination of NERICA varieties has not caused any reduction of pre-existing varieties. The short-duration NERICA are mainly used as a complement to the long-duration traditional varieties and thus enhance varietal diversity. Risks of diversity erosion seem limited in the current setting of farming system and diversity structure. However, at the village level, the diversity pattern is fragile as the proportion of farmers who used each variety of the village is low and heterogeneous. A continuous monitoring of the dynamics of rice varietal diversity in Guinea is needed.
Gender Quotas and Women's Substantive Representation: Lessons from Argentina
Authors: Franceschet Susan , Piscopo Jennifer M.
Published: September 2008

This article integrates the comparative literature on gender quotas with the existing body of research on women's substantive representation. Quota laws, which bring greater numbers of women into parliaments, are frequently assumed to improve women's substantive representation. We use the Argentine case, where a law mandating a 30% gender quota was adopted in 1991, to show that quotas can affect substantive representation in contradictory and unintended ways. To do so, we disaggregate women's substantive representation into two distinct concepts: substantive representation as process, where women change the legislative agenda, and substantive representation as outcome, where female legislators succeed in passing women's rights laws in the Argentine Congress. We argue that quota laws complicate both aspects of substantive representation. Quotas generate mandates for female legislators to represent women's interests, while also reinforcing negative stereotypes about women's capacities as politicians. Our case combines data from bill introduction and legislative success from 1989 to 2007 with data from 54 interviews conducted in 2005 and 2006. We use this evidence to demonstrate that representation depends on the institutional environment, which is itself shaped by quotas. Institutions and norms simultaneously facilitate and obstruct women's substantive representation.
Liberia's Election of Ellen Johnson-Sirleaf and Women's Executive Leadership in Africa
Authors: Adams Melinda
Published: September 2008

In November 2005, Ellen Johnson-Sirleaf became the first female elected head of state in sub-Saharan Africa. On the face of it, the fact that this important breakthrough occurred in Liberia may seem paradoxical given that Liberia recently came out of years of conflict and is one of the poorest countries in the world. Generally, the advancement of women politically has been associated with the economic advancement of a country (Inglehart and Norris 2003). However, Johnson-Sirleaf's victory is consistent with new trends on the continent regarding women's political leadership. Ten years ago, African women held just 10.7% of the seats in their legislatures, falling below the global average at the time of 12.2%. Today, women in Africa hold 17% of legislative seats, matching the global average. In several countries, women have made far greater progress: They hold nearly 50% of legislative seats in Rwanda (48.8%) and over 30% of seats in Mozambique, South Africa, Burundi, and Tanzania.
Seizing a Window of Opportunity: The Election of President Bachelet in Chile
Authors: Tobar Marcela Ríos
Published: September 2008

The election of Michelle Bachelet as president of Chile on January 15, 2006, was an historical milestone for women and gender equity, both in her own country and for Latin America in general, where women have made significant gains in terms of parliamentary representation but continue to confront great difficulties in being elected as heads of state. Bachelet's election as the first female president was astonishing and surprising in many respects. In contrast to the experiences of other societies where women have been competing for high-ranking offices for quite some time (see Holli in this issue), Bachelet was only the second woman ever to run for president in Chile, following Gladys Marin, a longtime Communist Party leader who ran for president in the 1999 election and won less than 4% of the vote.
The sea ice dynamics of Terra Nova Bay and Ross Ice Shelf Polynyas during a spring and winter simulation
Authors: Petrelli P. , Bindoff N. L. , Bergamasco A.
Published: September 2008

The Terra Nova Bay (TNB) and Ross Ice Shelf (RIS) polynyas are simulated using a coupled atmosphere–sea ice model in winter 2002 and summer 2000. The atmospheric component of the model is compared with Automatic Weather Stations (AWS) data and shows a significantly increased skill over the ECMWF atmospheric variables. During winter, the sea ice production in TNB is largely determined by katabatic winds. We estimate the monthly production rate to be 8.7 km3/month of sea ice during winter. In early summer (November), the katabatics are weaker and the sea ice production is more influenced by the synoptic wind. The net sea ice production is weaker during November at 1.2 km3/month. The summer production is characterized by a diurnal cycle of melt and sea ice formation. For small coastal polynyas, like TNB, it is important to resolve all the glacier valleys accurately. Increasing the model resolution by a factor of five leads to a doubling of the sea ice formation during winter simulations due to the point intensity of the katabatics winds. For open coastal polynyas, like RIS polynya, sea ice production is largely controlled by synoptic winds and resolution is less important. The RIS polynya production is 61.3 km3 during winter and 19.1 km3 during November. These results are comparable to RIS polynya observations. Although the TNB polynya has a smaller winter sea ice production, the sea ice rate of growth per unit area is 1.6 times that of the RIS polynya.
Recent decrease of summer nutrients concentrations and future possible shrinkage of the subarctic North Pacific high‐nutrient low‐chlorophyll region
Authors: Ono Tsuneo , Shiomoto Akihiro , Saino Toshiro
Published: September 2008

We found evidence that summertime surface nutrient concentration in the subarctic North Pacific (SANP), the third largest “high‐nutrient and low‐chlorophyll” (HNLC) region in the world oceans, has decreased during 1975 to 2005. The observed trend seemed independent from natural decadal/interannual variations and roughly explained by the combination of multidecadal increasing trend of sea surface temperature (SST) and the observed negative correlation of nutrient concentration vs. SST. These analyses indicated that the observed decrease is mainly due to the recent stratification of the upper ocean column caused by global warming. This nutrient trend has a potential to minimize the present SANP‐HNLC region by up to 25%, assuming that the observed trend continues until the end of this century.
Tropical Pacific–Atlantic climate‐driven switching of thermocline nutrient content and export production
Authors: Loubere Paul , Fariduddin Mohammad
Published: September 2008

In the modern tropics, thermocline nutrients upwell on the eastern sides of ocean basins and are used with varying efficiency in the different oceans. This leads to nutrient build‐up as well as elevated CO2 efflux in the Pacific, something not seen in the Atlantic. We present evidence that thermocline nutrient and export production during the last glacial were reduced in the Pacific but were higher in the Atlantic. The evidence indicates an increased ice age supply of nutrients to the tropical Atlantic thermocline, but a reduction in the Pacific; thus, supply to a more efficient biological pump in the Atlantic was raised while that to the inefficient Pacific was diminished. Transformation to modern conditions was a two step process through the deglacial. The results demonstrate large‐scale reorganization of nutrient flow in the Atlantic and Pacific basins. The observed changes had the potential for positive feedback on glacial–interglacial variation of atmospheric CO2 concentrations.
Is there a signal of sea‐level rise in Chesapeake Bay salinity?
Authors: Hilton T. W. , Najjar R. G. , Zhong L. , Li M.
Published: September 2008

We evaluate the hypothesis that sea‐level rise over the second half of the 20th century has led to detectable increases in Chesapeake Bay salinity. We exploit a simple, statistical model that predicts monthly mean salinity as a function of Susquehanna River flow in 23 segments of the main stem Chesapeake Bay. The residual (observed minus modeled) salinity exhibits statistically significant linear (p < 0.05) trends between 1949 and 2006 in 13 of the 23 segments of the bay. The salinity change estimated from the trend line over this period varies from −2.0 to 2.2, with 10 of the 13 cells showing positive changes. The mean and median salinity changes over all 23 cells are 0.47 and 0.72; over the 13 cells with significant trends they are 0.71 and 1.1. We ran a hydrodynamic model of the bay under present‐day and reduced sea level conditions and found a bay‐average salinity increase of about 0.5, which supports the hypothesis that the salinity residual trends have a significant component due to sea‐level rise. Uncertainties remain, however, due to the spatial and temporal extent of historical salinity data and the infilling of the bay due to sedimentation. The salinity residuals also exhibit interannual variability, with peaks occurring at intervals of roughly 7 to 9 years, which are partially explained by Atlantic Shelf salinity, Potomac River flow and the meridional component of wind stress.
Formation process of the Kuroshio large meander in 2004
Authors: Usui Norihisa , Tsujino Hiroyuki , Nakano Hideyuki , Fujii Yosuke
Published: September 2008

Formation process of the 2004 Kuroshio large meander has been examined using a data assimilation and prediction system. The small meander southeast of Kyushu that occurred in December 2003 remains stationary until the next spring. The vorticity analysis indicates that this small meander is maintained by a balance between the advection and the bottom pressure torque on the continental slope. This balance is achieved as a result of reducing the advection by a westward propagating negative‐temperature‐anomaly originating in the wind stress field. The small meander starts moving eastward around May 2004, when an anticyclonic eddy east of the Tokara Strait is intensified by coalescing of two anticyclonic eddies. At that time, a deep‐anticyclonic eddy is generated below the Kuroshio by a cross‐frontal flow. The deep‐anticyclonic eddy grows up during its eastward propagation. Then a southward flow in the eastern part of the eddy carries the Kuroshio path offshore, bringing about the large meander. The eddy energetic analysis indicates that baroclinic instability is essentially responsible for this large meander formation. The sensitivity analysis reveals that the small meander and the intensified anticyclonic eddy significantly affect the phase speed and the amplitude of the meander, respectively. It is also revealed that a slow phase speed and a large amplitude of the meander are regarded as conditions for the stationary large meander, which is also applicable to the past large meanders. In the 2004 large meander, these conditions coexist by the stationary small meander staying until the intensified anticyclonic eddy triggers baroclinic instability.
Regional Eta model experiments: SALLJEX and MCS development
Authors: Rozante José Roberto , Cavalcanti Iracema Fonsecade Albuquerque
Published: September 2008

The rainfall regime over La Plata Basin is strongly influenced by Mesoscale Convective Systems (MCS) that develop during night time, associated with the Low‐Level Jet (LLJ) to the east of the Andes. Since they are mesoscale systems, their predictability depends on the model resolution and its ability to represent the main features associated with their development. This study aimed at finding the best configuration of the regional Eta model applied to the region of frequent MCS development to the east of the Andes and to analyze the performance of the model at high resolution, simulating specific MCS cases using two convection schemes. Three experiments were performed for the South American Low‐Level Jet Experiment (SALLJEX) period. Performance of the nonhydrostatic version was better than the hydrostatic version in cases of MCS development. The use of estimated instead of climatological soil moisture in the model, improved the results for several synoptic variables. Evaluation of the convection parameterization scheme indicated a better simulation using the Kain‐Fritsch (KF) rather than the Betts‐Miller‐Janjic scheme in the cases of MCS development. Therefore the best configuration of the Eta model for the simulation of the MCS occurrences over northern Argentina is the nonhydrostatic version using KF convection scheme and estimated soil moisture. With this configuration, the model was able to simulate the precipitation and the main atmospheric characteristics associated with MCS development, such as the upper level jet, the LLJ, humidity, and associated mechanisms for ascending motion, 72 hours in advance.
Observational evidence for the radiative impact of Indonesian smoke in modulating the sea surface temperature of the equatorial Indian Ocean
Authors: Rajeev K. , Parameswaran K. , Nair Sandhya K. , Meenu S.
Published: September 2008

The smoke aerosol plume produced by intense forest fires over Indonesia during September–November 1997 provided a unique opportunity to investigate the radiative impact of aerosols on sea surface temperature (SST), primarily due to its episodic nature and occurrence of high aerosol optical depth (>0.8) for ∼2 months over the east equatorial Indian Ocean (EIO). The aerosol radiative effect was well discernible in SST because the month‐to‐month variation in shortwave aerosol direct cooling (ADC) was so large while the corresponding variations in the other governing factors such as surface wind and sea surface upwelling were less significant during this period, when the net cloud radiative forcing had a positive anomaly at the surface. The present study clearly shows that from September to October 1997, ADC at surface has increased by more than −46 Wm−2 over east EIO resulting a decrease in SST by >1°C. This might have provided a positive feedback to the Indian Ocean dipole influencing the meteorology of the south Asian region.
Calibrating climate‐δ18O regression models for the interpretation of high‐resolution speleothem δ18O time series
Authors: Fischer M. J. , Treble P. C.
Published: September 2008

Providing estimates of past climate changes on interannual–millenial timescales requires suitable regression models between climate and climate proxies. Many proxies appear to show relationships with climate that are timescale dependent. Any proxy‐climate model should be able to replicate the major patterns that are observed at multiple timescales. Here we develop a new climate‐isotope regression model for speleothems from a middle latitude site. In the low to middle latitudes, daily variation in precipitation isotopes (within individual months) is largely negatively correlated with daily rainfall amount. On interdecadal timescales, though, this relationship appears to be nonstationary. These two points provide a theoretical basis for a new climate‐isotope regression model in which the slope and the intercept of a δ18Oday–Pday line for a given month are modulated by organized patterns of climate variability, such as the extratropical zonal waves (including the annular modes). In constructing this new regression model, we show how daily precipitation–δ18O relationships can be estimated using only monthly δ18O data and daily rainfall amounts. The new regression model provides a consistent picture of 18O variability over a range of timescales, and this has not been the case with any previous climate‐isotope regression model.
Dissolved organic carbon characteristics in boreal streams in a forest‐wetland gradient during the transition between winter and summer
Authors: Ågren Anneli , Buffam Ishi , Berggren Martin , Bishop Kevin , Jansson Mats , Laudon Hjalmar
Published: September 2008

The character and quantity of dissolved organic carbon (DOC) were studied in nine small boreal streams and adjacent soils during two years, with focus on the spring snowmelt period. The streams cover a forest‐wetland gradient, spanning from 0% to 69% wetland coverage. Lower values of the absorbance ratio measured at 254 nm and 365 nm (A254/A365), in both soil plots and streams, indicated that wetland‐derived DOC had higher average molecular weight than forest DOC. Higher SUVA254 (DOC specific ultraviolet absorption at 254 nm) in wetland runoff indicated more aromatic DOC from wetlands than forests. During low flow, the stream DOC character was sensitive to the forest‐wetland proportion of the catchment, and when wetland coverage exceeded 10%, the streams appeared to be dominated by wetland‐derived DOC. During the spring snowmelt period, the character changed to lower molecular weight and more aliphatic DOC, particularly in streams with a high proportion of forest in the catchment. The forested soil solutions had higher A254/A365 in the surface horizons that were hydrologically activated during the high flow events, while wetland soil solution had relatively low A254/A365 at all depths. Consequently forest soils contributed more to stream DOC concentration during snowmelt that during winter low flow.
Simulation of spatial dependence in daily rainfall using multisite generators
Authors: Zheng Xiaogu , Katz Richard W.
Published: September 2008

A new approach for modeling the spatial dependence in rainfall occurrence is proposed. Being motivated by a technique for coupling Markov chains in interacting particle systems, it differs from existing approaches that only attempt to reproduce pairwise spatial correlations of rainfall occurrences or apply complex nonlinear models. It has the advantage of directly modeling the joint dependence among Markov chains for rainfall occurrence at multisites in a parsimonious manner. The proposed approach is integrated into a simple multisite rainfall generator, with rainfall amount at an individual site modeled by a chain‐dependent process. This generator is applied to estimate the spatial dependence in daily rainfall at a small number of sites within a catchment in New Zealand. In this case study, besides the spatial correlation in rainfall occurrence, the joint probability distribution of rainfall occurrence and the spatial correlation of rainfall intensity are also simulated reasonably well.
Relative importance of dynamical and chemical contributions to Arctic wintertime ozone
Authors: Tegtmeier S. , Rex M. , Wohltmann I. , Krüger K.
Published: September 2008

We present the first complete budget of the interannual variability in Arctic springtime ozone taking into account anthropogenic chemical and natural dynamical processes. For the winters 1991/1992 to 2003/2004 the Arctic chemical ozone loss is available from observations. This work investigates the dynamical supply of ozone to the Arctic polar vortex due to mean transport processes for the same winters. The ozone supply is quantified in a vortex‐averaged framework using estimates of diabatic descent over winter. We find that the interannual variability of both dynamical ozone supply and chemical ozone loss contribute, in equal shares, to the variability of the total ozone change. Moreover, together they explain nearly all of the interannual variability of Arctic springtime column ozone. Variability in planetary wave activity, characterized by the Eliassen‐Palm flux at 100 hPa, contributes significantly to the variability of ozone supply, chemical ozone loss and total springtime ozone.
Stabilization of glaciers terminating in closed water bodies: Evidence and broader implications
Authors: Geirsdóttir Áslaug , Miller Gifford H. , Wattrus Nigel J. , Björnsson Helgi , Thors Kjartan
Published: September 2008

The behavior of glaciers terminating in deep water is determined by the interaction of buoyancy, iceberg production, and the sensitivity of ice flow to subtle changes in resistance at the glacier bed. Modeling efforts assume rapid evacuation of icebergs, but some glaciers terminate in closed basins where icebergs may accumulate. Multibeam bathymetric survey of a glacial lake in Iceland that received outlet glaciers during the Little Ice Age document near parallel flow of narrow, ice fingers that extended up to 1 km beyond the grounding line. These previously unseen features apparently occurred when iceberg production exceeded iceberg melt, resulting in iceberg buttressing of the ice margin. Similar stabilization of ice flow may resolve long‐standing debates about past continental ice‐sheet behavior, including the rapid readvance of the Laurentide Ice Sheet into Lake Superior ca. 11 ka and the genesis of glacial flutes observed in the central Arctic Ocean basin.
Deep downward fluid percolation driven by localized crust dilatation in Iceland
Authors: Geoffroy Laurent , Dorbath Catherine
Published: September 2008

From a detailed seismic survey on a transform‐like plate setting in Iceland, we propose a spatial relationship between highly deformed crustal columns and areas of low Vp/Vs ratio, which are best explained by high fluid pressures at the base of the seismogenic crust. Combined with geological observations, our seismic data suggest transient and local increases in crust permeability at specific highly dilating areas triggered by dynamical stresses from high‐magnitude regional earthquakes. Fluids are then trapped at supercritical conditions in the deep brittle crust which, in turn, increases the capacity of the rocks to deform through cracking and faulting.
Using CO2 spatial variability to quantify representation errors of satellite CO2 retrievals
Authors: Alkhaled A. A. , Michalak A. M. , Kawa S. R.
Published: September 2008

Satellite measurements of column‐averaged CO2 dry‐air mole fraction (XCO2) will be used in inversion and data assimilation studies to improve the precision and resolution of current estimates of global fluxes of CO2. Representation errors due to the mismatch in spatial scale between satellite retrievals and atmospheric transport models contribute to the uncertainty associated with flux estimates. This study presents a statistical method for quantifying representation errors as a function of the underlying spatial variability of XCO2 and the spatial distribution of retrieved soundings, without knowledge of the true XCO2 distribution within model gridcells. Representation errors are quantified globally using regional XCO2 spatial variability inferred using the PCTM/GEOS‐4 model and a hypothetical atmospheric transport model with 1° × 1° resolution, 3 km2 retrieval footprints, and two different sounding densities.
Passive microwave (SSM/I) satellite predictions of valley glacier hydrology, Matanuska Glacier, Alaska
Authors: Kopczynski S. , Ramage J. , Lawson D. , Goetz S. , Evenson E. , Denner J. , Larson G.
Published: September 2008

We advance an approach to use satellite passive microwave observations to track valley glacier snowmelt and predict timing of spring snowmelt‐induced floods at the terminus. Using 37 V GHz brightness temperatures (Tb) from the Special Sensor Microwave Imager (SSM/I), we monitor snowmelt onset when both Tb and the difference between the ascending and descending overpasses exceed fixed thresholds established for Matanuska Glacier. Melt is confirmed by ground‐measured air temperature and snow‐wetness, while glacier hydrologic responses are monitored by a stream gauge, suspended‐sediment sensors and terminus ice velocity measurements. Accumulation area snowmelt timing is correlated (R2 = 0.61) to timing of the annual snowmelt flood peak and can be predicted within ±5 days.
CO2 efflux from Amazonian headwater streams represents a significant fate for deep soil respiration
Authors: Johnson Mark S. , Lehmann Johannes , Riha Susan J. , Krusche Alex V. , Richey Jeffrey E. , Ometto Jean Pierre H. B. , Couto Eduardo Guimarães
Published: September 2008

Large Amazonian rivers are known to emit substantial amounts of CO2 to the atmosphere, while the magnitude of CO2 degassing from small streams remains a major unknown in regional carbon budgets. We found that 77% of carbon transported by water from the landscape was as terrestrially‐respired CO2 dissolved within soils, over 90% of which evaded to the atmosphere within headwater reaches of streams. Hydrologic transport of dissolved CO2 was equivalent to nearly half the gaseous CO2 contributions from deep soil (>2 m) to respiration at the soil surface. Dissolved CO2 in emergent groundwater was isotopically consistent with soil respiration, and demonstrated strong agreement with deep soil CO2 concentrations and seasonal dynamics. During wet seasons, deep soil (2–8 m) CO2 concentration profiles indicated gaseous diffusion to deeper layers, thereby enhancing CO2 drainage to streams. Groundwater discharge of CO2 and its subsequent evasion is a significant conduit for terrestrially‐respired carbon in tropical headwater catchments.
Subglacial topography inferred from ice surface terrain analysis reveals a large un‐surveyed basin below sea level in East Antarctica
Authors: Le Brocq A. M. , Hubbard A. , Bentley M. J. , Bamber J. L.
Published: September 2008

A terrain analysis technique relating ice‐surface plan curvature to basal topography is applied to the Antarctic Ice Sheet. The technique suggests complex bed topography and a large subglacial basin more than 1500 m below present day sea level under the Recovery Glacier and its catchment in East Antarctica. Despite the importance of accurate subglacial topography for understanding the nature of ice flow and for numerical modeling, available data in this region are sparse. The presence of a large area of ice grounded below sea level, flowing at elevated velocities could have significant implications for the potential stability of this region of East Antarctica, previously thought to contain only small areas of marine ice sheet. The catchment region alone contains an ice volume equivalent to 2.6 m of global sea level rise, therefore it is important that the nature of the basal conditions in this region are better understood.
A Brownian walk model for slow earthquakes
Authors: Ide Satoshi
Published: September 2008

Along some subduction plate boundaries, slow deformation is observable as seismically detected deep low‐frequency tremor and geodetically detected slow slip events. These phenomena are considered as different manifestations of slow earthquakes characterized by fairly constant seismic moment rate. This paper presents a simple model of slow earthquakes that can explain wide variety of observed features including the steady moment rate and scaled energy, characteristics of tremor signals both in time and frequency domains, and the migration of the source location. In this model, slow earthquakes are represented as shear slip on circular faults whose radius is a random variable that is governed by a Langevin equation and three parameters, a diffusion coefficient, a damping coefficient, and a slip rate coefficient. This model expands on a previous scaling law for the slow earthquakes by providing a specific image of kinematics. Allowing for spatial variations of the parameters could potentially explain differences in behavior of slow slip events worldwide.
Thermospheric nitric oxide variability induced by nonmigrating tides
Authors: Oberheide J. , Forbes J. M.
Published: September 2008

The large influence of nonmigrating tides on nitric oxide variability in the lower thermosphere is revealed for the first time using data from the TIMED (tides) and SNOE (nitric oxide) satellites. Between March and October, a wave‐4 like longitude variation in nitric oxide density residuals is observed with peak‐to‐peak values of 40% between 30°S–30°N and 100–135 km. This variation becomes wave‐3 like in December and January with wave‐4/wave‐3 transitions in November and February. It is quantitatively shown that the nitric oxide longitude variations are caused by nonmigrating tides in neutral gas density. The DE3 (diurnal eastward wavenumber 3) tidal component causes the observed wave‐4 variation. The combination of DE2 (diurnal eastward wavenumber 2) and SE1 (semidiurnal eastward wavenumber 1) causes the observed wave‐3 variation. These results suggest that similar effects will be found in other constituents and airglow emissions important to the aeronomy of the mesosphere and lower thermosphere.
Northern Annular Mode impact on spring climate in the western United States
Authors: McAfee Stephanie A. , Russell Joellen L.
Published: September 2008

Shifts in stormtrack position associated with the Northern Annular Mode (NAM) are linked to temperature changes and reduced spring precipitation in the western United States. During the transition to spring following a high‐index winter, weakening of the stormtrack over the northeastern Pacific Ocean and western United States is shown to lead to warmer and drier conditions west of the Rocky Mountains and increased precipitation just east of the Rocky Mountains, consistent with observations of early spring onset in the western United States. Given projected increases in the average annular mode index and associated poleward shifts in the stormtrack, this analysis provides additional evidence that much of the western United States will experience more severe drought conditions over the next several decades, irrespective of changes in temperature, because of an earlier shift to warm‐season circulation patterns.
Influence of mechanical damage on fluid flow patterns investigated using CT scanning imaging and acoustic emissions techniques
Authors: David Christian , Menéndez Beatriz , Mengus Jean‐Marie
Published: September 2008

In order to get some insight into the influence of mechanical deformation on fluid flow patterns, we performed series of X‐ray CT scanning runs during capillary imbibition experiments to image the water front displacement in Bentheim sandstone samples. A three steps procedure was followed: 1) intact rock samples were tested, 2) the samples were deformed in creep experiments under triaxial conditions with recording of acoustic emissions, 3) the deformed samples experienced a second capillary imbibition test with CT scanning imaging. Using image analysis tools, relevant flow parameters like the height, velocity and curvature of the water front were measured. Stress‐induced damage had a significant impact on the flow patterns. However contrasted results were obtained: localized damage evidenced by acoustic emissions clustering resulted in one experiment in local disturbance of the flow patterns, whereas in the second one a fracture detected by CT scan did not modify the local flow geometry.
Fault reactivation and selective abandonment in the oceanic lithosphere
Authors: Delescluse M. , Montési L. G. J. , Chamot‐Rooke N.
Published: September 2008

Normal and transform faults originally formed at a spreading‐centre can be reactivated in diffuse plate boundary zones and in areas of lithospheric flexure such as at peripheral bulges to subduction zones. Using new seismic reflection profiles and modeling, we investigate how the original oceanic fabric is reactivated in the simple case of fault perpendicular compression. In the Central Indian Basin, well‐oriented normal paleofaults were reactivated with reverse motion at the very onset of deformation (9 Ma) but only a small subset remained active past ∼7 Ma, suggesting that most of the densely spaced small‐offset faults were abandoned while deformation localized onto fewer faults with larger spacing. We find a similar evolution using a 2D finite element code of lithospheric shortening using a pseudoplastic rheology. Weak zones, 3 km‐spaced and 30–40% weaker than the surrounding material, are introduced to simulate the fabric formed at the ridge axis. We show that reactivation and selective abandonment require strain weakening followed by strain‐rate weakening once a maturation threshold is reached. A maturation fault slip of less than 50 m is needed to produce a fault network similar to that in the Central Indian Ocean.
Energetic electron precipitation induced by space based VLF transmitters
Authors: Kulkarni P. , Inan U. S. , Bell T. F.
Published: September 2008

Numerical raytracing with Landau damping is used to calculate electron precipitation that would be induced by in situ sources located at L = 2 and L = 2.5, at the geomagnetic equator and also at a geomagnetic latitude of 20° along each field line. In accordance with the Wang and Bell (1970) model of antenna radiation in a magnetoplasma, we consider frequencies immediately below, approximately equal to, and 1 kHz above the local lower hybrid resonance frequency at each location and injected rays within 3° of the resonance cone. The magnetospherically reflecting (MR) whistler‐mode waves that are injected from such in situ sources propagate with a wave normal angle very close to the resonance cone. Compared to a single‐pass interaction, such MR waves precipitate up to 16 times more 100 keV to 5 MeV electrons. Waves injected at initial wave normal angles closer to the magnetic field, e.g., 45°, in fact precipitate fewer >1 MeV electrons than waves injected close to the resonance cone.
Auroral evidence of a localized magnetic anomaly in Jupiter's northern hemisphere
Authors: Grodent Denis , Bonfond Bertrand , Gérard Jean‐Claude , Radioti Aikaterini , Gustin Jacques , Clarke John T. , Nichols Jonathan , Connerney John E. P.
Published: September 2008

We analyze more than 1000 HST/Advanced Camera for Survey images of the ultraviolet auroral emissions appearing in the northern hemisphere of Jupiter. The auroral footprints of Io, Europa, and Ganymede form individual footpaths, which are fitted with three reference contours. The satellite footprints provide a convenient mapping between the northern Jovian ionosphere and the equatorial plane in the middle magnetosphere, independent of any magnetic field model. The VIP4 magnetic field model is in relatively good agreement with the observed footprint of Io. However, in the auroral kink sector, between the 80° and 150° System III meridians, the model significantly departs from the observation. One possible way to improve the agreement between the VIP4 model and the observed footprints is to include a magnetic anomaly. We suggest that this anomaly is characterized by a weakening of the surface magnetic field in the kink sector and by an added localized tilted dipole field. This dipole rotates with the planet at a depth of 0.245 RJ below the surface, and its magnitude is set to ∼1% of Jupiter's dipole moment. The anomaly has a very limited influence on the magnetic field intensity in the equatorial plane between the orbits of Io and Ganymede. However, it is sufficient to bend the field lines near the high‐latitude atmosphere and to reproduce the observed satellite ultraviolet footpaths. JUNO's in situ measurements will determine the structure of Jupiter's magnetic field in detail to expand on these results.
Surface water processes in the Indonesian throughflow as documented by a high‐resolution coral Δ14C record
Authors: Fallon Stewart J. , Guilderson Thomas P.
Published: September 2008

To explore the seasonal to decadal variability in surface water masses that contribute to the Indonesian throughflow, we have generated a 115‐year bimonthly coral‐based radiocarbon time series from a coral in the Makassar Straits. In the pre‐bomb (pre‐1955) era from 1890 to 1954, the radiocarbon time series occasionally displays a small seasonal signal (10–15‰). After 1954 the radiocarbon record increases rapidly, in response to the increased atmospheric 14C content caused by nuclear weapons testing. From 1957 to 1986 the record displays clear seasonal variability from 15 to 60‰ and the post‐bomb peak (163 per mil) occurred in 1974. The seasonal cycle of radiocarbon can be attributed to variations of surface waters passing through the South Makassar Strait. Southern Makassar is under the influence of the Northwest Monsoon, which is responsible for the high austral summer radiocarbon (North Pacific waters) and the Southeast Monsoon that flushes back a mixture of low (South Pacific and upwelling altered) radiocarbon water from the Banda Sea. The coral record also shows a significant 14C peak in 1955 due to the bomb‐14C water advected into this region from nuclear weapons tests in the Marshall Islands in 1954.
Use of radio occultation for long‐term tropopause studies: Uncertainties, biases, and instabilities
Authors: Staten Paul W. , Reichler Thomas
Published: September 2008

Research suggests that changes in tropopause structure can both indicate and impact changes in the global climate system. The Global Positioning System radio occultation (RO) technique shows tremendous potential for monitoring the global tropopause because of its precision, temporal consistency, and global measurement density. This study examines the capability of RO to monitor the global tropopause by addressing three specific objectives: (1) quantify sources of uncertainty in individual RO tropopause measurements, (2) examine mean bias and long‐term stability of RO tropopause parameters with respect to those obtained from radiosondes, and (3) distinguish between differences due to processing and RO instrument differences by comparing tropopause parameters from different RO products. In this study, we make use of data from four different RO missions, including the recent Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC). RO tropopause uncertainty is shown to be largely due to the use of a highly nonlinear tropopause definition (1.6 K or 510 m), although uncertainties in the RO derived temperature profiles themselves (0.25 K or 75 m) are still significant. Global mean temperature and height biases between RO instruments and radiosondes are within 0.5 K and 75 m. One long‐term RO data set examined in this study appeared to contain spurious temperature trends, but these have since been corrected. Tropopause measurements from different RO instruments are generally within 41 m and 0.1 K for the globe. Dissimilarly processed temperature data, however, can differ by as much as 2 K in the mean. These results confirm the precision of RO data, but also demonstrate the importance of consistent processing for long‐term tropopause temperature studies. Tropopause height data do not appear to be significantly affected by the differences in processing examined in this study.
Assessment of the quality of the Version 1.07 temperature‐versus‐pressure profiles of the middle atmosphere from TIMED/SABER
Authors: Remsberg E. E. , Marshall B. T. , Garcia‐Comas M. , Krueger D. , Lingenfelser G. S. , Martin‐Torres J. , Mlynczak M. G. , Russell J. M. , Smith A. K. , Zhao Y. , Brown C. , Gordley L. L. , Lopez‐Gonzalez M. J. , Lopez‐Puertas M. , She C.‐Y. , Taylor M. J. , Thompson R. E.
Published: September 2008

The quality of the retrieved temperature‐versus‐pressure (or T(p)) profiles is described for the middle atmosphere for the publicly available Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) Version 1.07 (V1.07) data set. The primary sources of systematic error for the SABER results below about 70 km are (1) errors in the measured radiances, (2) biases in the forward model, and (3) uncertainties in the corrections for ozone and in the determination of the reference pressure for the retrieved profiles. Comparisons with other correlative data sets indicate that SABER T(p) is too high by 1–3 K in the lower stratosphere but then too low by 1 K near the stratopause and by 2 K in the middle mesosphere. There is little difference between the local thermodynamic equilibrium (LTE) algorithm results below about 70 km from V1.07 and V1.06, but there are substantial improvements/differences for the non‐LTE results of V1.07 for the upper mesosphere and lower thermosphere (UMLT) region. In particular, the V1.07 algorithm uses monthly, diurnally averaged CO2 profiles versus latitude from the Whole Atmosphere Community Climate Model. This change has improved the consistency of the character of the tides in its kinetic temperature (Tk). The Tk profiles agree with UMLT values obtained from ground‐based measurements of column‐averaged OH and O2 emissions and of the Na lidar returns, at least within their mutual uncertainties. SABER Tk values obtained near the mesopause with its daytime algorithm also agree well with the falling sphere climatology at high northern latitudes in summer. It is concluded that the SABER data set can be the basis for improved, diurnal‐to‐interannual‐scale temperatures for the middle atmosphere and especially for its UMLT region.