Detection of iodine monoxide radicals in the marine boundary layer using laser induced fluorescence spectroscopy

A Laser Induced Fluorescence (LIF) instrument has been developed to detect iodine monoxide (IO) radicals in the atmosphere. An all solid-state Nd:YAG pumped Ti:Sapphire laser operating at approximately 445 nm was used to excite the (2,0) band of the IO A²Π_3/2 ← X²Π_3/2 electronic transition, with off-resonance fluorescence in the (2,5) band detected at 521 nm. The sensitivity of the instrument was determined by calibration. IO (between 10 and 150 pptV) was generated following the 184.9 nm photolysis of N₂O/CF₃I/N₂ mixtures with O₃ actinometry used to determine the photolysis flux. The detection limit was determined to be 0.3 pptV for a 300 s integration period, with an uncertainty of 23% (1σ). The instrument was deployed in August/September 2006 during the RHaMBLe (Reactive Halogens in the Marine Boundary Layer) campaign in Roscoff, France. Located on a small jetty, a few metres from the water’s edge at high tide, the instrument measured significant levels of IO on 11 days, with a maximum of 27.6 ± 3.2 pptV observed on one day (averaged over 10 s) representing the highest IO mixing ratio recorded in the marine boundary layer to date. IO displayed a clear diurnal profile with a maximum at low tide during the daytime. These results represent the first point measurements of IO in the atmosphere by LIF.     

New-type urbanization in China: Predicted trends and investment demand for 2015–2030

The future development of new-type urbanization has drawn great attention from both the government and public alike. In this context, the present study had three related research aims. Firstly, it sought to predict the urbanization and population dynamics in China at both national and provincial levels for the period of 2015 to 2030. Secondly, on this basis, it sought to examine the spatial variation of urbanization given the predicted national urbanization rate of 70.12%. Thirdly, it sought to estimate and evaluate the national and provincial demands of investment in the development of new-type urbanization. The main conclusions from this study were as follows: (1) The population size and urbanization rate will reach 1.445 billion and 70.12%, respectively, from 2015 to 2030. (2) The demographic dividend will vanish when the population pressure reaches its maximum. During this period, there will be 70.16 million urban population born. The suburban population that becomes urbanized will be 316.7 million, and thus the net increase in urban population will reach 386 million. (3) Although the urbanization rate of every Chinese province will increase during 2015–2030, it will do so unequally, while differences in urbanization quality among provinces will also be substantial. In some provinces, moreover, the urbanization quality is not compatible with their eco-social development. (4) A total of 4,105,380 billion yuan is required to fund new-type urbanization and the investment demand for each province varies greatly; for example, Guangdong province requires the most funding, amounting to approximately 148 times that required by Tibet, the province in least need of funding. In the final part of this study, policy suggestions concerning the investment of the new-type urbanization are put forward and discussed.     

Spatial variation in river runoff into a coastal area — An ecological approach

Carbon and nitrogen stable isotopes were used to investigate spatial variation in terrestrial particulate organic matter (POM) input to a coastal area off the Tagus river estuary. Isotopic variation in higher trophic level organisms was also examined, along the coast. This study was carried out in late summer, after a period of 3 months of low river flow. The overall aim was to determine if under such conditions the coastal area is enriched by the river plume and, particularly, if lower secondary productivity should be expected in some areas. Spatial variation was detected as a gradient of decreasing terrestrial input with increasing distance from the river. It was concluded that terrestrial carbon input was also incorporated into higher trophic levels and that organisms with lower mobility are more sensitive to the gradient in terrestrial input. Even in low flow conditions the whole fishing area remained under the influence of the river plume, which still accounted for 24% of the total POM 30 km from the river mouth. Additionally, δ¹⁵N values indicated pollution input from the river Tagus.     

A software tool for monitoring legal minimum length of landings: Case study of a fishery in southern Spain

The regulation of minimum legal size (MLS) of catches is a tool widely applied in the management of fisheries resources, although the MLS does not always coincide with the length at first maturity (LFM). The optimization of this management tool requires a series of quality control in fish markets and transportation. A software application has been developed to make the control of the landings of several target species easier and faster. In order to test and make this tool operational, six species of commercial interest were selected: four species of fish and two species of bivalves. It is proposed to estimate the proportion of illegal specimens in the studied lot from the proportion of illegal individuals found in the samples taken from this lot. The input data for the application are the minimum legal size (MLS) of the species and the total length (TL) of each specimen sampled. The output data is a statistical summary of the percentage of specimens of size less than the legal minimum (TL≤MLS) within different confidence intervals (90%, 95% and 99%). The software developed will serve as a fast, efficient and easy to manage tool that allows inspectors to determine the degree of compliance on MLS control and to make a decision supported by statistical proof on fishing goods.     

Constraining the origin and evolution of confined turbidite systems: southern Cretan margin,Eastern Mediterranean Sea (34°30–36°N)

Bathymetric, 9.5-kHz long-range sidescan sonar (OKEAN), seismic reflection and sediment-core data are used in the analysis of two tectonic troughs south of Crete, Eastern Mediterranean Sea. Here, up to 1.2 s two-way travel time (TWTT) of strata have accumulated since the Middle Miocene in association with extension in the South Aegean region. The study area comprises >100-km- long by >25-km-wide basins filled by sediments subdivided into two seismic units: (1) an upper Unit 1 deposited in sub-basins which follow the present-day configuration of the southern Cretan margin; (2) a basal Unit 2, more than 500 ms (TWTT) thick, accumulated in deeper half-graben/grabens distinct from the present-day depocentres. Both units overlap a locally stratified Unit 3 comprising the pre-Neogene core complex of Crete and Gavdos. In this work, the interpreted seismic units are correlated with the onshore stratigraphy, demonstrating that denudation processes occurring on Crete and Gavdos in response to major tectonic events have been responsible for high sedimentation rates along the proximal southern Cretan margin. Consequently, topographically confined sedimentary units have been deposited south of Crete in the last 12 Ma, including turbidites and other mass-flow deposits fed by evolving transverse and axial channel systems. Surface processes controlling facies distribution include the direct inflow of sediment from alluvial-fan systems and incising mountain rivers onto the Cretan slope, where significant sediment instability processes occur at present. In this setting, seismic profiles reveal eight different types of stratigraphic contacts on basin-margin highs, and basinal areas show evidence of halokinesis and/or fluid escape. The acquired data also show that significant changes to the margin’s configuration occurred in association with the post-Alpine tectonic and eustatic episodes affecting the Eastern Mediterranean.     

Rms-value and power spectrum of the photospheric intensity-fluctuations

The power spectrum and the rms-value of the granular intensity fluctuations were studied using granulation photographs of excellent quality obtained during the JOSO site testing campaign 1979 at Izaña. The observed power spectrum was corrected using various effective modulation transfer functions of the system: telescope+aberrations+atmospheric seeing, assuming different contributions of the atmospheric seeing. With this procedure a lower and upper limit for the ‘true’ power spectrum of the granular intensity fluctuations and thus for the rms-value could be derived: 7.2% <I _rms <12% at λ = 550 nm, with a most probable value of I _rms = 10.5%. We checked the validity of the upper limit by applying to our data a MTF (Deubner and Mattig, 1975), which certainly must lead to an overcorrection. This procedure lead to I _rms = 13.4%. Thus we can state that the true rms-value of the granular intensity fluctuations does certainly not exceed 13% at λ = 550 nm.