Cretaceous–Tertiary Rhenodanubian flysch wedge (Eastern Alps): clues to sediment supply and basin configuration from zircon fission-track data

The provenance of Cenomanian to Eocene flysch deposits accreted along the northern margin of the Eastern Alps has been investigated by means of zircon fission-track (FT) geochronology and zircon morphology. The Rhenodanubian flysch and Ybbsitz klippen zone comprise several nappes representing the Main flysch and Laab basins. The Laab basin received sediments of stable European provenance, indicated by pre-Variscan, Variscan, and Permian–Triassic zircon FT ages, and was thus located in the immediate south of the European margin. The Main flysch basin was supplied mainly from the evolving Eastern Alps and was therefore situated south of the Laab basin. Zircon populations with Permian to Jurassic cooling ages in the Main flysch basin are related to increased heat fluxes during the break-up of Pangaea and are probably derived from the northwestern part of the Eastern Alps. The dominant Cretaceous zircon FT cooling ages reflect Eoalpine metamorphism in the Austroalpine realm.     

A 16-ka δ18O record of lacustrine sugar biomarkers from the High Himalaya reflects Indian Summer Monsoon variability

We investigated a late glacial–Holocene lacustrine sediment archive located at 4,050 m a.s.l. in the small carbonate-free catchment of Lake Panch Pokhari, Helambu Himal, Nepal. A δ¹⁸O sugar biomarker record was established by applying novel compound-specific δ¹⁸O analysis of plant sugar biomarkers (Zech and Glaser in Rapid Commun Mass Spectrom 23:3522–3532, 2009). This method overcomes analytical challenges such as extraction and purification faced by previous methods aimed at using δ¹⁸O of aquatic cellulose as a paleoclimate proxy. The δ¹⁸O results for sugar biomarkers arabinose, xylose and fucose agree well and reveal a pronounced trend towards lower δ¹⁸O values during the deglaciation and the onset of the Bølling/Allerød interstadial. By contrast, the period of the Younger Dryas is characterized by higher δ¹⁸O values. The early Holocene again reveals lower δ¹⁸O values. We suggest that our lacustrine δ¹⁸O record reflects coupled hydrological and thermal control. It is strongly related to changes in the oxygen isotopic composition of paleo-precipitation and resembles the δ¹⁸O records of Asian speleothems. With respect to the ‘amount effect,’ the record is interpreted as reflecting the Indian Summer Monsoon intensity. The precipitation signal is, however, amplified in our record by evaporative ¹⁸O enrichment that is controlled by the ratio of precipitation to evaporation. We suggest that our δ¹⁸O record reflects the variability of the Indian Summer Monsoon, which was strong during the Bølling/Allerød interstadial and early Holocene, but weak during the Younger Dryas stadial. This interpretation is corroborated by a pollen-based index for Lake Panch Pokhari that estimated the strength of the Indian Summer Monsoon versus the strength of the Westerlies. Millennial-scale synchronicity with the Greenland δ¹⁸O temperature records highlights the previously suggested strong teleconnections between the Asian Monsoon system and North Atlantic climate variability.     

The need for data: natural disasters and the challenges of database management

Hundreds of natural catastrophes occur worldwide every year—there were 780 loss events per year on average over the last 10 years. Since 1980, these disasters have claimed over two million lives and caused losses worth US$ 3,000 billion. The deadliest disasters were caused by earthquakes: the tsunami following the Sumatra quake (2004) and the Haiti earthquake (2010) claimed more than 220,000 lives each. The Great East Japan Earthquake of 11 March 2011 was the costliest natural disaster of all times, with total losses of US$ 210 billion. Hurricane Katrina, in 2005, was the second costliest disaster, with total losses of US$ 140 billion (in 2010 values). To ensure that high-quality natural disaster analyses can be performed, the data have to be collected, checked and managed with a high degree of expertise and professionality. Scientists, governmental and non-governmental organisations and the finance industry make use of global databases that contain losses attributable to natural catastrophes. At present, there are three global and multi-peril loss databases: NatCatSERVICE (Munich Re), Sigma (Swiss Re) and EM-Dat (Centre for Research on the Epidemiology of Disasters). They are supplemented by numerous databases focusing on national or regional issues, certain hazards and specific sectors. This paper outlines the criteria and definitions relating to how global and multi-peril databases are operated, and the efforts being made to ensure consistent and internationally recognised standards of data management. In addition, it presents the concept and methodology underlying the NatCatSERVICE database, and points out the many challenges associated with data acquisition and data management.     

The use of GPS for marine positioning in Germany—requirements,experience, and concepts

Abstract

While beginning to establish a German Civil GPS Information and Observation Service in 1990, the actual and (near) future GPS market in Germany was analyzed. In addition, the feasibility of using GPS for water authority tasks has been studied during past years. Typical capabilities in this area are real‐time positioning for hydrographic surveying (kinematic application) and precise transfer of levels to tide gauges and verification at offshore positions.

The article describes the user interests, the requirements, some of the test campaigns, and the derived concepts for future applications.     

Recent climatic trends and linkages to river discharge in Central Vietnam

In this study, change in rainfall, temperature and river discharge are analysed over the last three decades in Central Vietnam. Trends and rainfall indices are evaluated using non‐parametric tests at different temporal levels. To overcome the sparse locally available network, the high resolution APHRODITE gridded dataset is used in addition to the existing rain gauges. Finally, existing linkages between discharge changes and trends in rainfall and temperature are explored. Results are indicative of an intensification of rainfall (+15%/decade), with more extreme and longer events. A significant increase in winter rainfall and a decrease in consecutive dry days provides strong evidence for a lengthening wet season in Central Vietnam. In addition, trends based on APHRODITE suggest a strong orographic signal in winter and annual trends. These results underline the local variability in the impacts of climatic change at the global scale. Consequently, it is important that change detection investigations are conducted at the local scale. A very weak signal is detected in the trend of minimum temperature (+0.2°C/decade). River discharge trends show an increase in mean discharge (31 to 35%/decade) over the last decades. Between 54 and 74% of this increase is explained by the increase in precipitation. The maximum discharge also responds significantly to precipitation changes leading to a lengthened wet season and an increase in extreme rainfall events. Such trends can be linked with a likely increase in floods in Central Vietnam, which is important for future adaptation planning and management and flood preparedness in the region. Copyright © 2012 John Wiley & Sons, Ltd.     

Managed aquifer recharge (MAR) by the construction of subsurface dams in the semi-arid regions: A case study of the Kalangi river basin, Andhra Pradesh

Overuse of groundwater in coastal areas, due to high population and agricultural activity results in seawater intrusion into the coastal aquifer. This paper presents the control measures taken to manage aquifer recharge (MAR) and also to overcome the problem of seawater intrusion into the coastal aquifer along the Kalangi river, Nellore district of Andhra Pradesh, India having connectivity with Pulicat (saltwater) lake estuary. Due to overexploitation of groundwater and less rainfall in past years, adjacent seawater has started intruding in the Kalangi river sub-surface and deteriorating groundwater quality up to 11.6 km from the confluence of the river with Pulicat lake. To prevent this situtation, subsurface dams were constructed in traditional manner using local earth material in three different places across the Kalangi river near Sullurpet town. The water storage capacities calculated after the sub-surface dams’ construction are 1.28 mcft at GK Engineering College, 6.23 mcft at Challamagudi and 3.143 mcft at Holy Cross School sites. The Holy Cross School sub-surface dam is the first full scale dam-cum-check dam constructed to prevent salt water intrusion in the Kalangi river at Sullurpet, Nellore district, Andhra Pradesh. At the Kalangi river estuary portion (at the mouth of sea) a groyne was reconstructed over old groyne site with the introduction of clay bed and wooden sheet piles at down stream. Apart from prevention of sea water entry into Kalangi river sub-surface (during seasons) the groyne top level was raised to prevent mixing of high sea water tides with fresh water and ensuring additional storage of fresh water at upstream side. The reconstructed groyne was serving the purpose of obstructing the surface seawater entry in the Kalangi river and water quality has improved in the river as well as in the wells. After construction of sub-surface dam, as per the Simpson ratio classification, there is substantial improvement of water quality in the SHAR infiltration well situated near the Holy Cross School sub-surface dam.