Longitudinal dispersion processes in the upper tamar estuary

Measurements of velocity, salinity, and suspended solids concentration have been used to investigate the intra-tidal variation of vertical and transverse shear-induced dispersion. For the study research the interaction of the longitudinal density gradient and vertical shear during the early part of the ebb tide accounted for much of the net longitudinal dispersion of solute landward. The same mechanism also is shown to lead to a net particulate transport landward. The landward flux, however, takes place during the flood tide. The field data are also used to elucidate the tidally averaged tidal pumping mechanism.     

Holocene climate variability as derived from alkenone sea surface temperature and coupled ocean-atmosphere model experiments

Holocene climate modes are identified by the statistical analysis of reconstructed sea surface temperatures (SSTs) from the tropical and North Atlantic regions. The leading mode of Holocene SST variability in the tropical region indicates a rapid warming from the early to mid Holocene followed by a relatively weak warming during the late Holocene. The dominant mode of the North Atlantic region SST captures the transition from relatively warm (cold) conditions in the eastern North Atlantic and the western Mediterranean Sea (the northern Red Sea) to relatively cold (warm) conditions in these regions from the early to late Holocene. This pattern of Holocene SST variability resembles the signature of the Arctic Oscillation/North Atlantic Oscillation (AO/NAO). The second mode of both tropical and North Atlantic regions captures a warming towards the mid Holocene and a subsequent cooling. The dominant modes of Holocene SST variability emphasize enhanced variability around 2300 and 1000 years. The leading mode of the coupled tropical-North Atlantic Holocene SST variability shows that an increase of tropical SST is accompanied by a decrease of SST in the eastern North Atlantic. An analogy with the instrumental period as well as the analysis of a long-term integration of a coupled ocean-atmosphere general circulation model suggest that the AO/NAO is one dominant mode of climate variability at millennial time scales.     

Thermal features at Volcanoes in the cascade range,as observed by aerial infrared surveys

There have been no substantial changes in the thermal patterns at the summit of Mount Rainier in the period September 1964–September 1966, within the detection limits of the infrared instrumentation. Some differences in radiance are attributed to differences in snow cover. The highest apparent temperature is at a snow-free area on the west flank of the summit cone, several hundred feet below the west crater rim. An anomaly at this site was recorded on both infrared surveys, but no prior reports of thermal activity here have been made by ground parties. Other anomalous thermal zones at the summit are on the northern quadrants of both crater rims. A very small, low-temperature fumarole reported on Mount Adams was not detected, nor were any other thermal manifestations recorded. One anomaly consisting of a close-spaced cluster of thermal spots was detected at The Boot on Mount St. Helens and corresponds to a known fumarole area. The only thermal feature seen on Mount Shasta is near the summit at a thermal spring that has been observed by many climbers. Two anomalies were found on the north flank of Lassen Peak. Thermal activity had not been previously reported at either site, though one is in a known solfatarized area. No ground investigation has been made at the other location. Much of the other thermal activity in the Lassen Peak area is in the northeast quadrant of Brokeoff Caldera. Most of these features are well documented in the literature; others not previously described are in fairly accessible areas and doubtless result from springs and fumaroles related to Brokeoff Caldera.     

Mean Profiles of Moisture Fluxes in Snow-Filled Boundary Layers

Profiles of moisture fluxes have been examined for convective boundary layers containing clouds and snow, using data derived from aircraft measurements taken on four dates during the 1983/1984 University of Chicago lake-effect snow project. Flux profiles were derived from vertical stacks of aircraft cross-wind flight legs taken at various heights over Lake Michigan near the downwind shore. It was found that, if ice processes are taken into account, profiles of potential temperature and water content were very similar to those presented in past studies of convective boundary layers strongly heated from below. Profiles of total water content and equivalent potential temperature adjusted for ice were nearly invariant with height, except very near the top of the boundary layer, suggesting that internal boundary-layer mixing processes were rapid relative to the rates at which heat and vapour were transported into the boundary layer through entrainment and surface fluxes. Ice was found to play a significant, measurable role in boundary-layer moisture fluxes. It was estimated that 40 to 57% of the upward vapour flux was returned to the surface in the form of snow, converting about 45 to 64% of the surface latent heat flux into sensible heat in the snow-producing process. Assuming advective fluxes are relatively small (thought to be appropriate after the first few tens of km over the lake as suggested by past studies), the boundary layer was found to warm at a rate faster than could be explained by surface heat fluxes and latent heat releases alone, the remainder of the heating presumably coming from radiational processes and entrainment. Discussions of moisture phase change processes throughout the boundary layer and estimates of errors of these flux measurements are presented.     

Zum Abbau von Formaldehyd durch adaptierte Bakterien

Municipal activated sludge was cultivated in a medium composed of formaldehyde, glucose and mineral salt. By passages with increasing formaldehyde content a bacterial culture was selected which remained active also at initial concentrations of 1 g/1 formaldehyde. With this culture, formaldehyde and glucose were oxidized simultaneously to formate and gluconate, which subsequently served simultaneously as substrate for the growth of bacteria. Glucose alone was also oxidized to gluconate, which then was used as substrate for growth. Formaldehyde alone was only oxidized. If the actual formaldehyde concentration was kept low, however, by fed-batch cultivation, it was assimilated also through formate formation. The biochemical background and the importance of the findings for the purification of formaldehyde-containing wastewaters are discussed.     

Effects of Amazon basin deforestation on regional atmospheric circulation and water vapor transport towards tropical South America

The water cycle over the Amazon basin is a regulatory mechanism for regional and global climate. The atmospheric moisture evaporated from this basin represents an important source of humidity for itself and for other remote regions. The deforestation rates that this basin has experienced in the past decades have implications for regional atmospheric circulation and water vapor transport. In this study, we analyzed the changes in atmospheric moisture transport towards tropical South America during the period 1961–2010, according to two deforestation scenarios of the Amazon defined by Alves et al. (Theor Appl Climatol 100(3-4):337–350, 2017). These scenarios consider deforested areas of approximately 28% and 38% of the Amazon basin, respectively. The Dynamic Recycling Model is used to track the transport of water vapor from different sources in tropical South America and the surrounding oceans. Our results indicate that under deforestation scenarios in the Amazon basin, continental sources reduce their contributions to northern South America at an annual scale by an average of between 40 and 43% with respect to the baseline state. Our analyses suggest that these changes may be related to alterations in the regional Hadley and Walker cells. Amazon deforestation also induces a strengthening of the cross-equatorial flow that transports atmospheric moisture from the Tropical North Atlantic and the Caribbean Sea to tropical South America during the austral summer. A weakening of the cross-equatorial flow is observed during the boreal summer, reducing moisture transport from the Amazon to latitudes further north. These changes alter the patterns of precipitable water contributions to tropical South America from both continental and oceanic sources. Finally, we observed that deforestation over the Amazon basin increases the frequency of occurrence of longer dry seasons in the central-southern Amazon (by between 29 and 57%), depending on the deforestation scenario considered, as previous studies suggest.