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The Bakken, one of the best-known oil producing shale plays in North America, is responsible for a renaissance on the Northern Great Plains as oil prices stay above $100 per [...]

As an avid golfer and fisherman, I was disgusted when I read 'Get Revenge' by T. Edward Nickens ('Best of Summer Fishing'). Outlining the best attire and time of day [...]

When storm surge and heavy precipitation co-occur, the potential for flooding in low-lying coastal areas is often much greater than from either in isolation. Knowing the probability of these compound events and understanding the processes driving them is essential to mitigate the associated high-impact risks. Here we determine the likelihood of joint occurrence of these two phenomena for the contiguous United States (US) and show that the risk of compound flooding is higher for the Atlantic/Gulf coast relative to the Pacific coast. We also provide evidence that the number of compound events has increased significantly over the past century at many of the major coastal cities. Long-term sea-level rise is the main driver for accelerated flooding along the US coastline; however, under otherwise stationary conditions (no trends in individual records), changes in the joint distributions of storm surge and precipitation associated with climate variability and change also augment flood potential. For New York City (NYC)—as an example—the observed increase in compound events is attributed to a shift towards storm surge weather patterns that also favour high precipitation. Our results demonstrate the importance of assessing compound flooding in a non-stationary framework and its linkages to weather and climate.

A nonlinear relation between the salinity field and the subtidal exchange circulation in the Tampa Bay estuary is demonstrated using observational data from 1999 to 2011. The data are averaged to form mean monthly climatological values of total freshwater discharge ( Q), axial and vertical salinity gradients, and subtidal vertical shear. Well‐known steady state solutions indicate that the exchange circulation is linearly proportional to the horizontal salinity gradient, assuming a constant vertical eddy viscosity ( Aeff). The exchange flow is found to be multivalued with respect to the horizontal salinity gradient, forming a hysteresis loop in parameter space that passes through three dynamical regimes. Regime I is relatively dry with weak salinity gradients and exchange circulation. Regime II is the wet season (June–September) in which all quantities rapidly increase. In regime III, the exchange flow persists even though Qand the axial salinity gradient are again low. Gradient Richardson numbers and Simpson numbers also form a loop in parameter space with Riremaining subcritical (turbulent) until the wet season when Ririses above criticality (weak vertical mixing) where it remains through the end of regime III. The Simpson number is in a narrow range around 0.2, indicating that the horizontal salinity gradient is always a driver of the exchange circulation. The Aeff, estimated from a parameterization of the Richardson number, decreases by almost an order of magnitude from regimes I to II. It remains low during III, indicating that the persistent stratification is insulating the exchange flow from destruction by tidal mixing during this time period. The relation between salinity and exchange circulation is nonlinearThis is the first such finding in an estuaryThe dynamics are understandable from known estuarine physics

Abstract: Estuarine salinity distributions reflect a dynamic balance between the processes that control estuarine circulation. At seasonal and longer time scales, freshwater inputs into estuaries represent the primary control on salinity distribution and estuarine circulation. El Niño-Southern Oscillation (ENSO) conditions influence seasonal rainfall and stream discharge patterns in the Tampa Bay, Florida region. The resulting variability in freshwater input to Tampa Bay influences its seasonal salinity distribution. During El Niño events, ENSO sea surface temperature anomalies (SSTAs) are significantly and inversely correlated with salinity in the bay during winter and spring. These patterns reflect the elevated rainfall over the drainage basin and the resulting elevated stream discharge and runoff, which depress salinity levels. Spatially, the correlations are strongest at the head of the bay, especially in bay sections with long residence times. During La Niña conditions, significant inverse correlations between ENSO SSTAs and salinity occur during spring. Dry conditions and depressed stream discharge characterize La Niña winters and springs, and the higher salinity levels during La Niña springs reflect the lower freshwater input levels.

Abstract: The importance of the El Niño-Southern Oscillation (ENSO) on regional-scale climate variability is well recognized although the associated effects on local weather patterns are poorly understood. Little work has addressed the ancillary impacts of climate variability at the community level, which require analysis at a local scale. In coastal communities water quality and public health effects are of particular interest. Here we describe the historical influence of ENSO events on coastal water quality in Tampa Bay, Florida (USA) as a test case. Using approximate randomized statistics, we show significant ENSO influences on water quality particularly during winter months, with significantly greater fecal pollution levels during strong El Niño winters and significantly lower levels during strong La Niña winters as compared to neutral conditions. Similar significant patterns were also noted for El Niño and La Niña fall periods. The success of the analysis demonstrates the feasibility of assessing local effects associated with large-scale climate variability. It also highlights the possibility of using ENSO forecasts to predict periods of poor coastal water quality in urban region which local agencies may use to make appropriate prepations.

Trajectory experiments in a thermocline layer of an Indian Ocean model are used to investigate the role of different meridional transport mechanisms and quantify spreading pathways and rates under different forcing. Particles are introduced along two boundaries: the south Indian Ocean at 30°S and the Indonesian Throughflow. Particles are advected horizontally within the layer by archived model velocity fields (° × ° resolution) for a period of 50 years. The velocity fields are the result of forcing the model by monthly mean climatology (case A). The distribution of particles within the Tropics suggests efficient water mass blending; model results show a mixture of three parts South Indian Central Water to one part Indonesian Throughflow. In agreement with chlorofluorocarbon (CFC) observations, transport of thermocline waters along the western boundary into the northern Indian Ocean occurs on timescales of less than two decades. Additional Lagrangian experiments carried out with the seasonality removed from the velocity fields directly (taking the mean in case B) and from the forcing (case C) allow the role of horizontal eddy transport to be evaluated. Significant northward transport of southern subtropical gyre waters along the western boundary does not occur unless there is eddy transport, even though the mean flow appears to dominate the cross-equatorial transport in the immediate vicinity of the equator. Particles reach northward of 10°N on shorter timescales (<20 yr) in case A compared with case C (>20 yr). Both the mean and seasonal forcing components are important for the meridional flux of particles. The results suggest that to adequately simulate meridional transport of mass and water mass properties in the Indian Ocean, models should include the full annual cycle. In a new methodology, CFC-11 concentrations along trajectories are calculated using observed CFC-11 concentrations for boundary conditions. Additional CFC observations allow model–data comparisons to be made in the interior of the domain. The method may be useful in other studies of transport rates and processes where both computing power and good quality high-resolution observations are available.

The article focuses on the innovative way of paving in Illinois. For the concrete containing Type IL cement, there were two 8-mile-long contracts and one 4-mile long-contract that totaled up to 20.6 lineal miles of three-lane-wide mainline paving. There were four paving contractors on the project including K-Five Construction Corp., FH Paschen/SN Nielsen, Plote Construction Inc., and R.W. Dunteman Co.

Several letters to the editor are presented in response to articles in previous issues including "The 20 Best Knives Ever Made," by David E. Petzal in June 2008 issue, "Get Revenge" by T. Edward Nickens, and "A Cry From the North" by T. Edward Nickens.