TEMPORAL EVOLUTION OF THERMAL STRUCTURES AND WINTER HEAT CONTENT CHANGE FROM VOS-XBT DATA IN THE CENTRAL MEDITERRANEAN SEA

Seasonal and year-to-year time evolution of the thermal structure, including the heat content change in the upper water column and its relationship with the surface net heat fluxes, have been studied at five locations in the central Mediterranean Sea. The study is based on temperature profiles collected during XBT surveys (eXpendable Bathy- Thermograph) carried out on ships of opportunity, in the framework of the MFSPP (Mediterranean Forecasting System Pilot Project), between September 1999 and May 2001. The five investigated zones are located in the southern Adriatic, NW Ionian, southern and northern Tyrrhenian, and Ligurian Sea. Gradual erosion of the thermocline in autumn, formation of a mixed layer in winter, and the onset of the stratification in spring, are common properties of the temporal evolution of thermal structures at all five locations. Moreover, in the southern Adriatic, a deep convection took place down to about 600m in winter 1999/2000. On the other hand, mild climatic conditions and small surface heat loss in autumn and winter 2000/2001 drastically reduced a mixing/ convection depth which hardly reached 200 m. Simultaneously, the NW Ionian remained slightly stratified throughout the winter period. The heat storage rate in the upper portion of the water column (down to 450 m) is compared with the air-sea net heat flux at a monthly scale. A heat content decrease is determined by the surface heat loss, and the processes such as lateral advection, or upwelling of the colder waters through the base of the water column (for example, in the southern Adriatic and Ionian Seas). Elsewhere (for example, in the northern Tyrrhenian and Ligurian Seas), the upwelling does not contribute significantly to the heat balance within the water column, since the vertical temperature gradients in deeper layers are negligible

The Surface Diffusion Flow with Elasticity in Three Dimensions

We establish the short-time existence of a smooth solution to the surface diffusion equation with an elastic term and without an additional curvature regularization in three space dimensions. We also prove the asymptotic stability of strictly stable stationary sets

An analysis of electron distributions in galaxy clusters by means of the flux ratio of iron lines FeXXV and XXVI

The interpretation of hard X-ray emission from galaxy clusters is still ambiguous and different models proposed can be probed using various observational methods. Here we explore a new method based on Fe line observations. Spectral line emissivities have usually been calculated for a Maxwellian electron distribution. In this paper a generalized approach to calculate the iron line flux for a modified Maxwellian distribution is considered. We have calculated the flux ratio of iron lines for the various possible populations of electrons that have been proposed to account for measurements of hard X-ray excess emission from the clusters A2199 and Coma. We found that the influence of the suprathermal electron population on the flux ratio is more prominent in low temperature clusters (as Abell 2199) than in high temperature clusters (as Coma).Comment: 6 pages, 3 figures, accepted for publication in A&

Temporal evolution of thermal structures and winter heat content change from VOS-XBT data in the central Mediterranean Sea

International audienceSeasonal and year-to-year time evolution of the thermal structure, including the heat content change in the upper water column and its relationship with the surface net heat fluxes, have been studied at five locations in the central Mediterranean Sea. The study is based on temperature profiles collected during XBT surveys (eXpendable Bathy-Thermograph) carried out on ships of opportunity, in the framework of the MFSPP (Mediterranean Forecasting System Pilot Project), between September 1999 and May 2001. The five investigated zones are located in the southern Adriatic, NW Ionian, southern and northern Tyrrhenian, and Ligurian Sea. Gradual erosion of the thermocline in autumn, formation of a mixed layer in winter, and the onset of the stratification in spring, are common properties of the temporal evolution of thermal structures at all five locations. Moreover, in the southern Adriatic, a deep convection took place down to about 600 m in winter 1999/2000. On the other hand, mild climatic conditions and small surface heat loss in autumn and winter 2000/2001 drastically reduced a mixing/convection depth which hardly reached 200 m. Simultaneously, the NW Ionian remained slightly stratified throughout the winter period. The heat storage rate in the upper portion of the water column (down to 450 m) is compared with the air-sea net heat flux at a monthly scale. A heat content decrease is determined by the surface heat loss, and the processes such as lateral advection, or upwelling of the colder waters through the base of the water column (for example, in the southern Adriatic and Ionian Seas). Elsewhere (for example, in the northern Tyrrhenian and Ligurian Seas), the upwelling does not contribute significantly to the heat balance within the water column, since the vertical temperature gradients in deeper layers are negligible. Key words. Oceanography: general (climate and interannual variability; descriptive and regional oceanography) ? Oceanography: physical (air-sea interactions

Hydro-geomorphological modelling of ash-fall pyroclastic soils for debris flow initiation and groundwater recharge in Campania (southern Italy)

Carbonate mountain ranges surrounding volcanic centers in the Campania region of southern Italy are covered by discontinuous ash-fall pyroclastic deposits of variable thicknesses. The cover thickness and stratigraphy are relevant to hydrological controls on both rainfall-induced landslides and groundwater recharge. To improve understanding of the hydrologic regimes within the pyroclastic soil mantle, a hydrological monitoring station was installed upslope of a debris flow source area in the Sarno Mountains. Monitoring results demonstrate consistently unsaturated conditions, strong seasonal and inter-annual variations in pressure head, and delayed and damped dynamics at different depths related to rainfall and evapotranspiration patterns. Frequencies of recorded pressure head time series were analyzed to quantify the seasonal hydrological regime of the cover as a whole, as well as variations within individual soil horizons. For the whole ash-fall pyroclastic soil cover, variable seasonal frequencies of pressure head were recognized exceeding landslide alert and groundwater recharge threshold values. Analysis of frequencies for individual soil horizons showed a strongly delayed timing determining in winter and summer an opposite hydrological behavior between the shallowest and deepest soil horizons. A model that accounts for topographic variations in cover thickness and these hydrological regimes is proposed to quantify hydro-geomorphological controls on debris flows triggering and groundwater recharge. The model is based on the estimation of ash-fall pyroclastic soil thickness along slopes by the total thickness fallen in a given area and an inverse relationship with slope angle, allowing the assessment at the distributed scale over peri-volcanic mountainous areas. Moreover, it links the spatially variable thicknesses of ash-fall pyroclastic soils to the amount of soil water storage allowing the assessment of frequency of hydrological conditions leading to debris flow initiation and groundwater recharge

Dystonia: sparse synapses for D2 receptors in striatum of a DYT1 knock-out mouse model

Dystonia pathophysiology has been partly linked to downregulation and dysfunction of dopamine D2 receptors in striatum. We aimed to investigate the possible morpho-structural correlates of D2 receptor downregulation in the striatum of a DYT1 Tor1a mouse model. Adult control Tor1a+/+ and mutant Tor1a+/− mice were used. The brains were perfused and free-floating sections of basal ganglia were incubated with polyclonal anti-D2 antibody, followed by secondary immune-fluorescent antibody. Confocal microscopy was used to detect immune-fluorescent signals. The same primary antibody was used to evaluate D2 receptor expression by western blot. The D2 receptor immune-fluorescence appeared circumscribed in small disks (~0.3–0.5 μm diameter), likely representing D2 synapse aggregates, densely distributed in the striatum of Tor1a+/+ mice. In the Tor1a+/− mice the D2 aggregates were significantly smaller (μm2 2.4 ± SE 0.16, compared to μm2 6.73 ± SE 3.41 in Tor1a+/+) and sparse, with ~30% less number per microscopic field, value correspondent to the amount of reduced D2 expression in western blotting analysis. In DYT1 mutant mice the sparse and small D2 synapses in the striatum may be insufficient to “gate” the amount of presynaptic dopamine release diffusing in peri-synaptic space, and this consequently may result in a timing and spatially larger nonselective sphere of influence of dopamine action