Comment on “Study on the reliable computation time of the numerical model using the sliding temporal correlation method”

The paper, “Study on the reliable computation time of the numerical model using the sliding temporal correlation method,” was published in Theoretical and Applied Climatology. In that work, the sliding temporal correlation analysis is employed to investigate the predictable time of two typical chaotic numerical models, namely the Lorenz system and the Chen chaotic system. However, it has been recently shown by us when using a linear scaling in time and state variables that generically, the Chen system is only a particular case of the Lorenz system, with time reversion if the parameter c is positive. Consequently, to study the Chen chaotic system is simply to consider the Lorenz system integrated backwards.     

Lower Carboniferous post-orogenic granites in central-eastern Sierra de Velasco,Sierras Pampeanas,Argentina: U–Pb monazite geochronology,geochemistry and Sr–Nd isotopes

The central-eastern part of the Sierra de Velasco (Sierras Pampeanas, NW Argentina) is formed by the large Huaco (40 × 30 km) and Sanagasta (25 × 15 km) granite massifs and the small La Chinchilla stock (2 × 2 km). The larger granites intrude into Ordovician metagranitoids and crosscut Devonian (?) mylonitic shear zones, whereas the small stock sharply intrudes into the Huaco granite. The two voluminous granites are biotitic-muscovitic and biotitic porphyritic syeno- to monzogranites. They contain small and rounded tonalitic and quartz-dioritic mafic microgranular enclaves. The small stock is an equigranular, zinnwaldite- and fluorite-bearing monzogranite. The studied granites are silica-rich (SiO₂ >70%), potassium-rich (K₂O >4%), ferroan, alkali-calcic to slightly calk-alkalic, and moderately to weakly peraluminous (A/CNK: 1.06–1.18 Huaco granite, 1.01–1.09 Sanagasta granite, 1.05–1.06 La Chinchilla stock). They have moderate to strong enrichments in several LIL (Li, Rb, Cs) and HFS (Nb, Ta, Y, Th, U) elements, and low Sr, Ba and Eu contents. U–Pb monazite age determinations indicate Lower Carboniferous crystallization ages: 350–358 Ma for the Huaco granite, 352.7 ± 1.4 Ma for the Sanagasta granite and 344.5 ± 1.4 Ma for the La Chinchilla stock. The larger granites have similar ?Nd values between ?2.1 and ?4.3, whereas the younger stock has higher ?Nd of ?0.6 to ?1.4, roughly comparable to the values obtained for the Carboniferous San Blas granite (?1.4 to ?1.7), located in the north of the sierra. The Huaco and Sanagasta granites have a mainly crustal source, but with some participation of a more primitive, possibly mantle-derived, component. The main crustal component can be attributed to Ordovician peraluminous metagranitoids. The La Chinchilla stock derives from a more primitive source, suggesting an increase with time in the participation of the primitive component during magma genesis. The studied granites were generated during a post-orogenic period in a within-plate setting, possibly as a response to the collapse of the previous Famatinian orogen, extension of the crust and mantle upwelling. They are part of the group of Middle Devonian–Lower Carboniferous granites of the Sierras Pampeanas. The distribution and U–Pb ages of these granites suggests a northward arc-parallel migration of this mainly post-orogenic magmatism with time.     

Evolution of exhumation and erosion in western West Gondwanaland as recorded by detrital zircons of late Neoproterozoic and Cambrian sedimentary rocks of NW and Central Argentina

The evolution of the provenance areas for Late Neoproterozoic, Cambrian and Early Ordovician sedimentary and meta-sedimentary rocks of north central and northwest Argentina is discussed using 123 maximum ages of detrital zircons from 42 samples from this and previously published studies. Most detrital zircon ages fall into two groups: 1,200–900 Ma and 670–545 Ma. These ages are essentially identical for the non- to very low grade metamorphic late Neoproterozoic to Early Cambrian Puncoviscana Formation and the low to high grade metamorphic rocks of Eastern Sierras Pampeanas. Hence, both units are related to similar provenance areas at the same time of sedimentation. The time span from zircon crystallization in the Earth’s crust to exhumation and erosion may be very long. This is important when determining maximum ages of sedimentary rocks. Variation of zircon maxima may also be influenced by concurrent sedimentary cover of proposed provenance areas. For the late Mesoproterozoic to early Neoproterozoic zircon age group, an active mountain range of the southwest Brazilian Sunsás orogen is the most probable provenance area. The younger, late Neoproterozoic zircons are related to the continuously developing mountains of the Brasiliano orogen of southwest and south central Brazil. Young zircons, up to 514 Ma, from fossil-bearing Puncoviscana and Suncho Formation outcrops are related to late Early Cambrian volcanism contemporaneous with sedimentation. This situation continues through the Late Cambrian to the Early Ordovician, but the Sunsás orogen provenance diminishes as possible Río de la Plata craton origins become important.     

Pressure and density gradients in H II Regions

Here we discuss the effects of large ambient pressures and decreasing density gradients on the observed properties of dusty UC hii regions. Dust absorption can effectively reduce the size of the photo ionized region, and density gradients can modify the spectral index of the emission. The effects of the density gradients seem to be present in both galactic and extragalactic HII regions.     

A New Ionosphere Monitoring Technology Based on GPS

Although global positioning system (GPS) was originally planned as a satellite-based radio-navigation system for military purposes, civilian users have significantly increased their access to the system for both, commercial and scientific applications. Almost 400 permanent GPS tracking stations have been stablished around the globe with the main purpose of supporting scientific research. In addition, several GPS receivers on board of low Earth orbit satellites fitted with special antennas that focus on Earth's horizon, are tracking the radio signals broadcasted by the high-orbiting GPS satellites, as they rise and set on Earth horizon. The data of these ground and space-born GPS receivers, readily accessible through Internet in a ‘virtual observatory’ managed by the International GPS Service, are extensively used for many researches and might possibly ignite a revolution in Earth remote sensing. By measuring the changes in the time it takes for the GPS signals to arrive at the receiver as they travel through Earth's atmosphere, scientists can derive a surprising amount of information about the Earth's ionosphere, a turbulent shroud of charged particles that, when stimulated by solar flares, can disrupt communications around the world. This contribution presents a methodology to obtain high temporal resolution images of the ionospheric electron content that lead to two-dimensional vertical total electron content maps and three-dimensional electron density distribution. Some exemplifying results are shown at the end of the paper.     

Changes in solar irradiance and atmospheric turbidity in Costa Rica during the total solar eclipse of July 11, 1991

Solar global radiation was measured in several places in Costa Rica during the total solar eclipse that occurred on July 11, 1991. In two of these places, Puntarenas and Santa Cruz, measurements in the ultraviolet range (295–385 nm) were also taken. In Santa Cruz, a normal incidence pyrheliometer with Schott filters OG530 and RG630 was used to measure direct solar radiation in its whole range, and in the 530–2800 nm and 630–2800 wavebands respectively. Global radiation, and consequently direct, diffuse and irradiance in any of the wavebands considered, decreased gradually as the sun was being eclipsed and reached zero during the totality, then increased to their normal values. Data registered in Santa Cruz were used to determine Ångstrom's atmospheric turbidity parameters and. Computations show that between 13:00 and 14:30 LT (local time), decreased and increased significantly. This indicates that atmospheric turbidity was high and large particles were more abundant than small ones. The size of hygroscopic particles increased during the eclipse when temperature decreased and relative humidity increased in a comparatively short time.     

Progressive Build Up Of Co 2 In The AtmosphereOf Venus Through Multiple Volcanic Resurfacing Events

In absence of other mechanisms, the main input of CO₂into the Venusian atmosphere is via volcanic out gassing. Since Venus can be regarded as a planet-wide large igneous province, we can expect large quantities of CO₂ being transferred into its atmosphere via volcanic out gassing. We have quantified the maximum possible amount of CO₂ that can be out gassed via a single massive episode of resurfacing of the planet. This figure (5.6 × 10¹⁹ kg of CO₂) is about 8 times smaller than the total CO₂ present in the Venusian atmosphere (4.55 × 10²⁰ kg CO₂). The lack of planet-wide, efficient mechanisms for the recycling of CO₂ on Venus indicates that CO₂ has progressively accumulated in the atmosphere. Based on these considerations we suggest that the “equivalent” to eight global resurfacing episodes would be required to account for the present values of CO_{2 atmosphere}. This revised version was published online in July 2006 with corrections to the Cover Date.     

The Gulf of California: Review of ecosystem status and sustainability challenges

The Gulf of California is unique because of its geographical location and conformation. It hosts diverse ecosystems and important fisheries that support industry and provide livelihood to coastal settlements. It is also the site of interests and problems, and an intense interaction among managers, producers, and conservationists. In this report, we scrutinize the abiotic (hydrography, climate, ocean circulation, and chemistry) and biotic (phyto- and zooplankton, fish, invertebrates, marine mammals, birds, and turtles) components of the marine ecosystem, and some particular aspects of climate variability, endemisms, harmful algal blooms, oxygen minimum layer, and pollution. We also review the current conditions and conflicts around the main fisheries (shrimp, small and large pelagic fishes, squid, artisanal and sportfishing), the most important human activity in the Gulf of California. We cover some aspects of management and conservation of fisheries, especially the claimed overexploitation of fish resources and the ecosystems, and review proposals for creating networks of marine protected areas. We conclude by identifying main needs for information and research, particularly the integration of data bases, the implementation of models and paleoreconstructions, establishment of monitoring programs, and the evaluation of fishing impacts and management actions.     

Solving positioning problems with minimal data

GPS Solutions - Global and local positioning systems (LPS) make use of nonlinear equations systems to calculate coordinates of unknown points. There exist several methods, such as Sturmfels’...