Evolution of sedimentary environments of the middle Jiangsu coast, South Yellow Sea since late MIS 3

An evolutionary model of sedimentary environments since late Marine Isotope Stage 3 （late MIS 3, i.e., ca. 39 cal ka BP） along the middle Jiangsu coast is presented based upon a reinterpretation of core 07SR01, new correlations between adjacent published cores, and shallow seismic profiles recovered in the Xiyang tidal channel and adjacent northern sea areas. Geomorphology, sedimentology, radiocarbon dating and seismic and sequence stratigraphy are combined to confirm that environmental changes since late MIS 3 in the study area were controlled primarily by sea-level fluctuations, sediment discharge of paleo-rivers into the South Yellow Sea （SYS）, and minor tectonic subsidence, all of which impacted the progression of regional geomorphic and sedimentary environments （Le., coastal barrier island freshwater lacustrine swamp, river floodplain, coastal marsh, tidal sand ridge, and tidal channel）. This resulted in the formation of a fifth-order sequence stratigraphy, comprised of the parasequence of the late stage of the last interstadial （Para-Sq2）, including the highstand and forced regressive wedge system tracts （HST and FRWST）, and the parasequence of the postglacial period （Para-Sql）, including the transgressive and highstand system tracts （TST and HST）. The tidal sand ridges likely began to develop during the postglacial transgression as sea-level rise covered the middle Jiangsu coast at ca. 9.0 cal ka BP. These initially submerged tidal sand ridges were constantly migrating until the southward migration of the Yellow River mouth to the northern Jiangsu coast during AD 1128 to 1855. The paleo-Xiyang tidal channel that was determined by the paleo-tidal current field and significantly different from the modern one, was in existence during the Holocene transgressive maxima and lasted until AD 1128. Following the capture of the Huaihe River in AD 1128 by the Yellow River, the paleo-Xiyang tidal channel was infilled with a large amount of river-derived sediments from AD 1128 to 1855, causing the emergence of some of the previously submerged tidal sand ridges. From AD 1855 to the present, the infilled paleo-Xiyang tidal channel has undergone scouring, resulting in its modern form. The modern Xiyang tidal channel continues to widen and deepen, due both to strong tidal current scouring and anthropogenic activities.     

Cyclic and Seasonal Beach Response: A Comparison of Oceanside and Bayside Beaches

This study compares the cyclic and seasonal geomorphic responses of oceanside and bayside beaches on Sandy Hook Spit, New Jersey. It was hypothesized that the different nature of onshore wind regimes at bayside and oceanside beaches would cause different types of beach change. On the east-facing ocean shoreline, rates of beach change are related to weather patterns associated with the passage of mid-latitude cyclonic storms. Bayside beach change is related to the influence of the prevailing westerlies. Storm erosion and post-storm deposition is more rapid on oceanside beaches. Swell waves occurring between storms rapidly reinstate pre-storm equilibrium conditions. Lower bay-side wave energies occurring between storms have little effect on profile development, and foreshore slopes inherited from previous storms undergo little change. Bayside beaches therefore appear to be more in equilibrium with storm conditions than oceanside beaches.

Changes in foreshore slope, beach volume, and beach position associated with individual storm events are compared to seasonal trends to test the applicability of the Hayes cyclic model of beach development to both oceanside and bayside beaches. There is evidence of a cyclic trend of develop-ment on the more exposed ocean sites and seasonal development on the more sheltered bayside sites, which suggests that cyclic development may be causally related to the difference among the energy levels of the storm and nonstorm wave regimes.     

ADAPTATION TO GLOBAL ENVIRONMENTAL CHANGE *

Atmospheric carbon dioxide is expected to double by A.D. 2050, raising global temperatures 2 to 3°C. A model for climatic deviations is presented, based upon paleoclimatic experience 5,000 to 8,000 years ago, when midlatitude temperatures were 1.5 to 2.5°C higher. The economic prognosis includes a United States barely able to meet its own agricultural needs and a substantial overall reduction of world food supplies. The revolutionary implications for contemporary sociopolitical alignments suggest an urgent need for long-range planning and more, historically oriented research.     

The effect of horizontal resolution on ocean surface heat fluxes in the ECMWF model

Annual mean ocean surface heat fluxes have been studied as a function of horizontal resolution in the ECMWF model (cycle 33) and compared with Oberhuber's COADS (1959–1979) based empirical estimates. The model has been run at resolutions of T21, T42, T63 and T106 for 15 months with prescribed monthly varying climatological SST and sea ice. The T42 simulation was extended to 2 years, which enabled us to determine that many differences between the resolution runs were significant and could not be explained by the fact that individual realizations of an ensemble of years can be expected to give different estimates of the annual mean climate state. In addition to systematic differences between the modeled and the observed fluxes, the simulated fields of surface shortwave and longwave radiation showed much more spatial variability than the observed estimates. In the case of the longwave radiation this may be attributable more to deficiencies in the observations than to errors in the model. The modeled latent and sensible heat fields were in better agreement with observations. The primary conclusion concerning the dependence of ocean surface fluxes on resolution is that the T21 simulation differed significantly from the higher resolution runs, especially in the tropics. Although the differences among the three higher resolution simulations were generally small over most of the world ocean, there were local areas with large differences. It appears, therefore, that in relation to ocean surface heat fluxes, a resolution greater than T42 may not be justified for climate model simulations, although the locally large differences found between the higher resolution runs suggest that convergence has not been achieved everywhere even at T106.     

Chemical Mechanism Development: Laboratory Studies and Model Applications

Within the German Tropospheric Research Programme (TFS) numerous kinetic and mechanistic studies on the tropospheric reaction/degradation of the following reactants were carried out: oxygenated VOC, aromatic VOC, biogenic VOC, short-lived intermediates, such as alkoxy and alkylperoxy radicals.At the conception of the projects these selected groups were classes of VOC or intermediates for which the atmospheric oxidation mechanisms were either poorly characterised or totally unknown. The motivation for these studies was the attainment of significant improvements in our understanding of the atmospheric chemical oxidation processes of these compounds, particularly with respect to their involvement in photooxidant formation in the troposphere. In the present paper the types of experimental investigations performed and the results obtained within the various projects are briefly summarised. The major achievements are highlighted and discussed in terms of their contribution to improving our understanding of the chemical processes controlling photosmog formation in the troposphere.     

Prediction Errors Associated with Sparse Grid Estimates of Flows over Hills

Numerical simulations of geophysical flows have to be done on very sparse grids. Nevertheless, flows over moderately sloped hills can be predicted quite accurately as long as the near ground vertical resolution is reasonably dense. Recirculation flows behind steeper hills are associated with slow convergence towards grid independent integrations, but even then moderately stratified flows of this type can be predicted usefully accurately. For better horizontal grids than about half the hill-height Δx ₁/H ≈ 0.5 or so, separation and recirculating domains are predicted with an error factor comparable to 0.3. The characteristic wavelength of lee waves is predicted more accurately while the lee wave amplitude and the maximum turbulence intensity in recirculating domains are underestimated by factors comparable to 0.3. Strongly stratified flows may be associated with hydraulic transitions and even this is predicted on quite coarse grids, up to say Δx ₁/H ≈ 0.5. However, the details of such flows turn out to be predicted with considerable errors also on high-resolution grids. Inaccurate modelling of stratified turbulence is a main contributor to this error.     

Spatial variability of water vapor turbulent transfer within the boundary layer

Although the physics of evaporation within the inner region of the boundary layer is believed to be well understood, observations of mass-energy exchange processes have been hindered by the limitations of point sensors. A combination of point sensors and active remote sensing, namely, water-Raman Lidar measurements, offers new opportunities to study relatively large areas at temporal and spatial scales previously unattainable. Results from experiments over uniform canopies both confirm some traditional theories and challenge some of the underlying assumptions concerning the homogeneity of the surface-atmosphere interface and the use of point sensors to characterize large areas.This work was performed under the auspices of the U.S. Department of Energy. The authors would like to thank F. Archuleta, J. Archuleta, F. Barnes, W. Clements, K. Muller and W. Porch of LANL, R. Whitis of USDA, R. Jackson and P. Pinter of USDA-WCL, and L. Balick of EG&G for their invaluable time and support.     

Characterization of a major refractory component of marine dissolved organic matter

Refractory carboxyl-rich alicyclic molecules (CRAM) are characterized in marine dissolved organic matter (DOM) using nuclear magnetic resonance spectroscopy and ultrahigh resolution mass spectrometry. CRAM are distributed throughout the water column and are the most abundant components of deep ocean DOM ever characterized. CRAM are comprised of a complex mixture of carboxylated and fused alicyclic structures with a carboxyl-C:aliphatic-C ratio of 1:2 to 1:7. CRAM are expected to constitute a strong ligand for metal binding, and multiple coordination across cations could promote aggregation and marine gel formation thereby affecting CRAM reactivity and the bioavailability of nutrients and trace metals. It appears CRAM are ultimately derived from biomolecules with structural similarities to sterols and hopanoids. The occurrence of CRAM in freshwater and terrestrial environments seems likely, considering the global distribution of biomolecules and the similarities of biogeochemical processes among environments.     

Betrachtungen über die Grundschicht

Zusammenfassung 1. Es werden die einzelnen Vorgänge besprochen, die das eigentümliche Verhalten der Veränderlichkeit von Druck und Temperatur in ihrer vertikalen Verteilung erklären sollen. Wenn ein unteres an der Erdoberfläche vorhandenes Druckausgleichsniveau vorhanden ist und ein weiteres in grösserer Höhe, so müssen Temperaturänderungen in dem einen Niveau durch solche eines anderen ausgeglichen, kompensiert werden. Es wird gezeigt, dass dem kompensierenden Einfluss der mittleren und oberen Troposphäre ein kompensierender Einfluss der Kälte- und Wärmewellen aus dem Bereiche der Grundschicht entgegenwirkt, sodass letzten Endes das Druckausgleichsniveau nicht mehr am Erdboden liegt, sondern in eine Höhe verschoben wird, die der ungefähren Höhe der Grundschicht entspricht. — 2. Der Einfluss von Reibung und Konvektion auf die Bildung der Grundschicht wird besprochen. Die Reibung wirkt langsam und immer schichtweise. Die Konvektion wirkt rascher, aber zunächst immer nur lokal. Im Verlaufe längerer Zeit kann aber auch die Konvektion eine Homogenisierung der unteren Luftschichten bewirken, also eine Luftschicht von einem einheitlichen Charakter schaffen. Dieser Prozess wird noch verstärkt, wenn die Konvektion mit Kondensation verbunden ist. Jetzt ist eine weitere Ueberhöhung der Grundschicht möglich. Da dieser Prozess aber über weite Räume nicht von gleicher Grösse ist, wird diese Ueberhöhung vielfach gebietsweise verschieden sein. Die Grundschicht vom Böenwettertyp hat daher gewöhnlich keine einheitliche Oberfläche über weite Gebiete hinweg. — 3. Ein weiterer Faktor, der für die Bildung der Grundschicht von Bedeutung ist, ist die Strahlung. Da der Beitrag, den jeder der drei Faktoren (Reibung, Konvektion, Strahlung) zur Bildung der Grundschicht beisteuert, nicht errechnet werden kann, muss man sich zunächst mit einer qualititativen Abschätzung der Einflüsse der einzelnen an der Bildung der Grundschicht beteiligten Faktoren begnügen. Ein entsprechendes Schema wird vorgelegt und besprochen.

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Summary 1. There are discussed individual proceedings which shall explain the characteristic behaviour of pressure, and temperature instability in their vertical distribution. When there exists equalization of pressure on a lower level near the ground, and again on a higher level, changes of temperature on one level will be compensated by such on another level. It is shown that the compensating influence of middle and upper troposphere is opposed by the compensating influence of cold, and heat waves from the ground layer, ultimately resulting in the removal of the level of pressure equalization from the ground to an altitude roughly corresponding to the height of ground layer. — 2. The influence of friction and convection on the formation of ground layer is discussed. While friction is acting slowly and by layers, convection is acting more rapidly, but only locally at first. In the long run however, also convection can produce homogeneity of the lower layers of the atmosphere, i. e. an atmospheric layer of uniform character. This process is being intensified when convection is associated with condensation. Then, another increase in height of the ground layer will be possible. However, as this process will not be of similar intensity over wide stages, the increase in height will vary locally. Therefore, generally the ground layer of the squally weather type will not possess a uniform surface extending over wide areas. — 3. Another important factor in the formation of ground layer is radiation. Since the share taken by each of the three factors (friction, convection, radiation) cannot be computed, one must be satisfied with qualitative valuation of the influence of the factors participating in the formation of ground layer. An appropriate scheme is submitted and discussed.