Distribution of ostracods in west-central Argentina related to host-water chemistry and climate: implications for paleolimnology

Ecological and biogeographical studies of Neotropical non-marine ostracods are rare, although such information is needed to develop reliable paleoecological and paleoclimatic reconstructions for the region. An extensive, yet little explored South American area of paleoclimatic interest, is the arid-semiarid ecotone (Arid Diagonal) that separates arid Patagonia from subtropical/tropical northern South America, and lies at the intersection of the Pacific and Atlantic atmospheric circulation systems. This study focused on the Laguna Llancanelo basin, Argentina, a Ramsar site located within the Arid Diagonal, and was designed to build a modern dataset using ostracods (diversity, spatial distribution, seasonality, habitat preferences) and water chemistry. Cluster and multivariate analysis of the data indicated that salinity is the most significant variable segregating two ostracod groups. Limnocythere aff. staplini is the only species that develops abundant populations in the saline ephemeral Laguna Llancanelo during almost all seasons, and is accompanied by scarce Cypridopsis vidua in summer. The latter species is abundant in freshwater lotic sites, where Ilyocypris ramirezi, Herpetocypris helenae, and Cyprididae indet. are also found in large numbers. Darwinula stevensoni, Penthesilenula incae, Heterocypris incongruens, Chlamydotheca arcuata, Chlamydotheca sp., Herpetocypris helenae, and Potamocypris smaragdina prefer freshwater lentic conditions (springs), with C. arcuata and Chlamydotheca sp. found only in the Carapacho warm spring, which has a year-round constant temperature of ~20 °C. Seasonal sampling was necessary because some taxa display a highly seasonal distribution. Species that were recorded have either subtropical or Patagonian affinities, although a few taxa are endemic or common to both regions. These data can serve as modern analogues for reconstructing the late Quaternary history of the area, and to investigate the extent and position of the arid/semiarid ecotone (Arid Diagonal) during past glacial/interglacial cycles.     

Delayed Seasonal Transition of Tropical Wave Activity in the CMIP3 Global Climate Models

This study evaluates the seasonal cycle of the activity of convectively coupled equatorial waves(CCEWs),including mixed Rossby-gravity(MRG) and tropical depression-type(TD-type) waves,based on the twentieth century experiments of 18 global climate models(GCMs) from the Coupled Model Intercomparison Project phase 3(CMIP3).The ensemble result of the 18 GCMs shows that the observed seasonal cycle of MRG and TD-type wave activity cannot be well reproduced.The seasonal transition of wave activity from the southern hemisphere to the northern hemisphere is delayed from April in the observations to May in the simulations,indicating that the simulated active season of tropical waves in the northern hemisphere is delayed and shortened.This delayed seasonal transition of tropical wave activity is associated with a delayed seasonal transition of simulated mean precipitation.The mean precipitation in April and May shows a double-ITCZ problem,and the horizontal resolution is important to the delayed seasonal transition of wave activity.Because of the coincident seasonal cycle of MRG and TD-type wave activity and tropical cyclone(TC) geneses,the delayed seasonal transition of wave activity may imply a similar problem of TC genesis in the GCMs,namely,a delayed and shortened TC season in the northern hemisphere.     

RATES OF ORGANIC CARBON ACCUMULATION IN YOUNG MINERAL SOILS NEAR BURROUGHS GLACIER,GLACIER BAY,ALASKA

The functional relationship between organic carbon in surface mineral horizons of fine-grained soils and time of soil development is examined in a chronosequence of soils deglaciated within 40 years of sampling. Rates of carbon accumulation increased through time in the first 4 decades of pedogenesis. Little carbon accumulated in the first 10 years, but rapid accumulation occurred over the next 22 years as alders (Alnus crispa) began to colonize.

Several chronofunctions of carbon accumulation are derived for the Burroughs data. A second-order polynomial function provides a good model of carbon accumulation in the first four decades of pedogenesis that is stronger and more significant than conventional exponential and power function models. A data set extended to 1000 years based on earlier studies in the region, indicates that carbon accumulation rates in this proglacial environment can be expressed by a sigmoidal curve. Several conventional chronofunctions derived from the extended data are appropriate for various stages of pedogenesis, but none provides accurate approximations over the entire 1000 years of pedogenesis. [Key words: Glacier Bay, Alaska, soil, carbon, chronofunction.]     

A double continuous approach to visualization and analysis of categorical maps

A method to visualize multiple membership maps, called ‘Colour mixture’ (CM) is described and compared with alternative techniques: defuzzification and Pixel mixture. Six landform parameters were used to derive the landform classes using supervised fuzzy k-means classification. The continuous categorical map is derived by GIS calculations with colours, where colour values are considered to represent the taxonomic space spanned by the attribute variables. Coordinates of the nine class centres (landform facets) were first transformed from multivariate to two-dimensional attribute space using factor analysis, and then projected on the Hue Saturation Intensity (HSI) colourwheel. The taxonomic value was coded with the Hue and confusion with Saturation. To improve visual impression, saturation was replaced with whiteness. Classes that were closer in attribute space were merged into similar generic colours. The CM technique limits the derived mixed-colour map to seven generic hues independently of the total number of classes, which provides a basis for automated generalization. The confusion index derived from the mixed-colour map was used to derive primary boundaries and to locate areas of higher taxonomic confusion.     

Lincolnshire – gaps and more gaps

The history of the possible flows of rivers through the Lincoln and Ancaster Gaps, and other gaps in Lincoln Edge and the Lincolnshire Wolds, is far from settled; puzzles remain. Quaternary geology influenced the geomorphological phenomena above.     

Current climate data rescue activities in Australia

正1.Introduction Recovering historical instrumental climate data is crucial for identifying long-term climate variability and change,putting present climate into context and constraining future climate projections(Brunet and Jones,2011).In other words,to understand the future,we need to improve our understand-     

A Study of Governance Arrangements for Land Use and Natural Resource Management Planning in Cape York Peninsula

Complex intersecting social, economic and environmental dilemmas in Australia's Cape York Peninsula present a number of challenges for planners seeking to develop and implement land use and natural resource management (NRM) plans. There have been five different attempts at land use and NRM planning in Cape York Peninsula over the last 20 years. These processes have (to greater or lesser extents) failed to deliver community-owned and government-supported plans to guide development and/or the management of the region's natural resources. The region is remote, sparsely populated, and home to a significant Indigenous population. Much of the contestation within the region surrounds the access, use and ownership of the region's internationally valuable natural resources. This paper reviews, from the literature, the relevancy and applicability of criteria for best practice planning and governance. A range of identified best practice governance and planning principles are applied to assess the governance arrangements for planning in the Peninsula. The paper finds that decision-making arrangements for land use and NRM planning in the Peninsula are still in their infancy and are inadequate to support effective outcomes. The paper concludes that broader attention to best practice principles in governance for planning is needed to improve planning outcomes.     

An improved genetic programming to SSM/I estimation typhoon precipitation over ocean

This article proposes an improved multi‐run genetic programming (GP) and applies it to estimate the typhoon rainfall over ocean using multi‐variable meteorological satellite data. GP is a well‐known evolutionary programming and data mining method used to automatically discover the complex relationships among nonlinear systems. The main advantage of GP is to optimize appropriate types of function and their associated coefficients simultaneously. However, the searching efficiency of traditional GP can be decreased by the complex structure of parse tree to represent the multiple input variables. This study processed an improvement to enhance escape ability from local optimums during the optimization procedure. We continuously run GP several times by replacing the terminal nodes at the next run with the best solution at the current run. The current method improves GP, obtaining a highly nonlinear meaningful equation to estimate the rainfall. In the case study, this improved GP (IGP) described above combined with special sensor microwave imager (SSM/I) seven channels was employed. These results are then verified with the data from four offshore rainfall stations located on islands around Taiwan. The results show that the IGP generates sophisticated and accurate multi‐variable equation through two runs. The performance of IGP outperforms the traditional multiple linear regression, back‐propagated network (BPN) and three empirical equations. Because the extremely high values of precipitation rate are quite few and the number of zero values (no rain) is very large, the underestimations of heavy rainfall are obvious. A simple genetic algorithm was therefore used to search for the optimal threshold value of SSM/I channels, detecting the data of no rain. The IGP with two runs, used to construct an appropriate mathematical function to estimate the precipitation, can obtain more favourable results from estimating extremely high values. Copyright © 2011 John Wiley & Sons, Ltd.     

Overwash sedimentation associated with a large-scale northeaster

The December 1, 1974 northeaster was a significant event in terms of sediment transport with 20 m³ of sand per meter of dune breach being carried onto the backdune area of Assateague Island, Maryland as overwash. Previous investigators have reported larger transport rates for landfall hurricanes, but this is the largest amount recorded for a winter northeaster. The Ash Wednesday Storm, March 6–8, 1962, was a much larger event, but no quantitative data exists for overwash deposition.The resulting sedimentary deposit can be interpreted by defining sedimentation units. Inverse sediment grading was predominant, but normal grading occurred when the material was monomineralic and the unit totally depositional in nature. The timing of the storm surge was recorded in some sections as a distinctive heavy mineral enrichment in the sediment.