Elevation dependence of cosmogenic 36Cl production in Hawaiian lava flows

Abstract We measured an elevation profile of cosmogenic 36 Cl in two well-preserved lava flows on Mauna Kea, Hawaii (19.8°N, 155.5°W ) in order to directly constrain the elevation dependence of cosmogenic nuclide production rates. The flows are verticallyextensive hawaiites erupted at 40.1 ± 0.6 and 62.2 ± 1.0 ka from point-vents on the upper flanks of Mauna Kea. The average paleo cutoff rigidity (a measure of geomagnetic shielding of cosmic rays) for these flows is 11 GV and their paleo-elevation range is 2100-3700 m. Production of 36 Cl is dominated by neutron reactions, with the high-energy 39 K(n,x) and 40 Ca(n,x) mechanisms accounting for nearly half of the 36 Cl production and the low-energy reaction 35 Cl(n,γ) responsible for the remaining half. Production by negative muons is small at the elevations of our samples, accounting for less than 2% of the total production in the lowest elevation samples. The elevation dependence of 36 Cl production measured in these lava flows is described by an effective attenuation length of 138 ± 5 g cm − 2 . This result is close to the value of 140 g cm − 2 determined from neutron monitor surveys of high-energy nucleon fluxes, but significantly below the value of 149 g cm − 2 determined from measurements of low-energy neutrons. The predicted atmospheric attenuation length for these lava flows, incorporating both high-and low-energy mechanisms, is 144 g cm − 2 . The good agreement between the 36 Cl elevation profile and cosmic-ray surveys validates the use of neutron flux measurements to scale 36 Cl production rates when production by muons is negligible

Soil water content in southern England derived from a cosmic-ray soil moisture observing system - COSMOS-UK

Cosmic-ray soil moisture sensors have the advantage of a large measurement footprint (approximately 700 m in diameter) and are able to operate continuously to provide area-averaged near-surface (top 10-20 cm) volumetric soil moisture content at the field scale. This paper presents the application of this technique at four sites in southern England over almost 3 years. Results show the soil moisture response to contrasting climatic conditions during 2011-2014, and are the first such field-scale measurements made in the UK. These four sites are prototype stations for a UK COsmic-ray Soil Moisture Observing System (COSMOS-UK), and particular consideration is given to sensor operating conditions in the UK. Comparison of these soil water content observations with the Joint UK Land Environment Simulator (JULES) 10 cm soil moisture layer shows that these data can be used to test and diagnose model performance, and indicates the potential for assimilation of these data into hydro-meteorological models. The application of these large-area soil water content measurements to evaluate remotely-sensed soil moisture products is also demonstrated. Numerous applications and the future development of a national COSMOS-UK network are discussed

COSMOS: the COsmic-ray Soil Moisture Observing System

The newly-developed cosmic-ray method for measuring area-average soil moisture at the hectometer horizontal scale is being implemented in the COsmic-ray Soil Moisture Observing System (or the COSMOS). The stationary cosmic-ray soil moisture probe measures the neutrons that are generated by cosmic rays within air and soil and other materials, moderated by mainly hydrogen atoms located primarily in soil water, and emitted to the atmosphere where they mix instantaneously at a scale of hundreds of meters and whose density is inversely correlated with soil moisture. The COSMOS has already deployed more than 50 of the eventual 500 cosmic-ray probes, distributed mainly in the USA, each generating a time series of average soil moisture over its horizontal footprint, with similar networks coming into existence around the world. This paper is written to serve a community need to better understand this novel method and the COSMOS project. We describe the cosmic-ray soil moisture measurement method, the instrument and its calibration, the design, data processing and dissemination used in the COSMOS project, and give example time series of soil moisture obtained from COSMOS probes

Middle pleistocene glaciation in Patagonia dated by cosmogenic-nuclide measurements on outwash gravels

The well-preserved glacial record in Argentine Patagonia offers a ~ 1 Ma archive of terrestrial climate extremes in southern South America. These glacial deposits remain largely undated beyond the range of radiocarbon dating at ca. 40 ka. Dating old glacial deposits (> several 105 a) by cosmogenic surface exposure methods is problematic because of the uncertainty in moraine degradation and boulder erosion rates. Here, we show that cobbles on outwash terraces can reliably date ‘old’ glacial deposits in the Lago Pueyrredón valley, 47.5° S, Argentina. Favorable environmental conditions (e.g., aridity and strong winds) have enabled continuous surface exposure of cobbles and preservation of outwash terraces. The data demonstrate that nuclide inheritance is negligible and we therefore use the oldest surface cobbles to date the deposit. 10Be concentrations in outwash cobbles reveal a major glacial advance at ca. 260 ka, concurrent with Marine Isotope Stage 8 (MIS 8) and dust peaks in Antarctic ice cores. A 10Be concentration depth-profile in the outwash terrace supports the age and suggests a low terrace erosion rate of ca. 0.5 mm ka− 1. We compare these data to exposure ages obtained from associated moraines and find that surface boulders underestimate the age of the glaciation by ~ 100 ka; thus the oldest boulders in this area do not date closely moraine deposition. The 10Be concentration in moraine cobbles help to constrain moraine degradation rates. These data together with constraints from measured 26Al/10Be ratios suggest that all moraine boulders were likely exhumed after original deposition. We determine the local Last Glacial Maximum (LGM) occurred at ~ 27–25 ka, consistent with the maximum LGM in other parts of Patagonia

Validation of spaceborne and modelled surface soil moisture products with cosmic-ray neutron probes

The scale difference between point in situ soil moisture measurements and low resolution satellite products limits the quality of any validation efforts in heterogeneous regions. Cosmic Ray Neutron Probes (CRNP) could be an option to fill the scale gap between both systems, as they provide area-average soil moisture within a 150–250 m radius footprint. In this study, we evaluate differences and similarities between CRNP observations, and surface soil moisture products from the Advanced Microwave Scanning Radiometer 2 (AMSR2), the METOP-A/B Advanced Scatterometer (ASCAT), the Soil Moisture Active and Passive (SMAP), the Soil Moisture and Ocean Salinity (SMOS), as well as simulations from the Global Land Data Assimilation System Version 2 (GLDAS2). Six CRNPs located on five continents have been selected as test sites: the Rur catchment in Germany, the COSMOS sites in Arizona and California (USA), and Kenya, one CosmOz site in New South Wales (Australia), and a site in Karnataka (India). Standard validation scores as well as the Triple Collocation (TC) method identified SMAP to provide a high accuracy soil moisture product with low noise or uncertainties as compared to CRNPs. The potential of CRNPs for satellite soil moisture validation has been proven; however, biomass correction methods should be implemented to improve its application in regions with large vegetation dynamics

Ecosystem-scale measurements of biomass water using cosmic ray neutrons

Accurate estimates of biomass are imperative for understanding the global carbon cycle. However, measurements of biomass and water in the biomass are difficult to obtain at a scale consistent with measurements of mass and energy transfer, ~1 km, leading to substantial uncertainty in dynamic global vegetation models. Here we use a novel cosmic ray neutron method to estimate a stoichiometric predictor of ecosystem-scale biomass and biomass water equivalent over tens of hectares. We present two experimental studies, one in a ponderosa pine forest and the other in a maize field, where neutron-derived estimates of biomass water equivalent are compared and found consistent with direct observations. Given the new hectometer scale of nondestructive observation and potential for continuous measurements, we anticipate this technique to be useful to many scientific disciplines

Conceptual modelling to assess how the interplay of hydrological connectivity, catchment storage and tracer dynamics controls nonstationary water age estimates

Acknowledgements We would like to gratefully acknowledge the data provided by SEPA, Iain Malcolm. Mark Speed, Susan Waldron and many MSS staff helped with sample collection and lab analysis. We thank the European Research Council (project GA 335910 VEWA) for funding and are grateful for the constructive comments provided by three anonymous reviewers.Peer reviewedPostprin

The role of pharmacotherapy, rehabilitation and nutrition in the treatment of children with West syndrome

West syndrome is classified as an epileptic encephalopathy. This syndrome is diagnosed in children aged 4-6 months. Its unsuccessful prognosis and complicated aetiology affects the delay of psychomotor development and cognitive functions of children. Repeated attacks inhibit the realization of next tasks assigned to the children’s age. Properly conducted treatment of West syndrome should be interdisciplinary and include pharmacological treatment, diet and rehabilitation. Pharmacological treatment of West syndrome includes: the ACTH hormone, corticosteroids (prednisolone), vigabatrin, valproic acid, nitrazepam, pyridoxine, zonisamide, topiramide. The therapy includes also a ketogenic diet which assumes changes in the proportion of nutrients. Predominant ingredient in the diet are fats (80-90% of daily intake of nutrients). Further, children with West syndrome require neuropsychological and motor rehabilitation (Vojta therapy, NDT- Bobath therapy). Cooperation of therapeutic experts with parents of the children makes it possible to achieve therapeutic benefits through improvement of the children's quality of life. Mental disability and cognitive impairment associated with the syndrome result in the loss of skills already acquired by children, therefore motivation and support of the children's parents is a significant task assigned to therapeutic team members

Location and mechanism of the Little Skull Mountain earthquake as constrained by satellite radar interferometry and seismic waveform modeling

We use interferometric synthetic aperture radar (InSAR) and broadband seismic waveform data to estimate source parameters of the 29 June 1992, M_s 5.4 Little Skull Mountain (LSM) earthquake. This event occurred within a geodetic network designed to measure the strain rate across the region around Yucca Mountain. The LSM earthquake complicates interpretation of the existing GPS and trilateration data, as the earthquake magnitude is sufficiently small that seismic data do not tightly constrain the epicenter but large enough to potentially affect the geodetic observations. We model the InSAR data using a finite dislocation in a layered elastic space. We also invert regional seismic waveforms both alone and jointly with the InSAR data. Because of limitations in the existing data set, InSAR data alone cannot determine the area of the fault plane independent of magnitude of slip nor the location of the fault plane independent of the earthquake mechanism. Our seismic waveform data tightly constrain the mechanism of the earthquake but not the location. Together, the two complementary data types can be used to determine the mechanism and location but cannot distinguish between the two potential conjugate fault planes. Our preferred model has a moment of ∼3.2 × 10^(17) N m (M_w 5.6) and predicts a line length change between the Wahomie and Mile geodetic benchmarks of ∼5 mm