scholarly journals Characterizing the Non-linear Interactions Between Tide, Storm Surge, and River Flow in the Delaware Bay Estuary, United States

2021 ◽  
Vol 8 ◽  
Author(s):  
Ziyu Xiao ◽  
Zhaoqing Yang ◽  
Taiping Wang ◽  
Ning Sun ◽  
Mark Wigmosta ◽  
...  
Keyword(s):  
United States ◽  
Water Level ◽  
Transition Zone ◽  
Storm Surge ◽  
River Flow ◽  
The United States ◽  
Delaware Bay ◽  
Domain Model ◽  
Non Linear ◽  
Linear Interactions

Low-lying coastal areas in the mid-Atlantic region are prone to compound flooding resulting from the co-occurrence of river floods and coastal storm surges. To better understand the contribution of non-linear tide-surge-river interactions to compound flooding, the unstructured-grid Finite Volume Community Ocean Model was applied to simulate coastal storm surge and flooding in the Delaware Bay Estuary in the United States. The model was validated with tide gauge data in the estuary for selected hurricane events. Non-linear interactions between tide-surge-river were investigated using a non-stationary tidal analysis method, which decomposes the interactions’ components at the frequency domain. Model results indicated that tide-river interactions damped semidiurnal tides, while the tide-surge interactions mainly influenced diurnal tides. Tide-river interactions suppressed the water level upstream while tide-surge interaction increased the water level downstream, which resulted in a transition zone of damping and enhancing effects where the tide-surge-river interaction was prominent. Evident compound flooding was observed as a result of non-linear tide-surge-river interactions. Furthermore, sensitivity analysis was carried out to evaluate the effect of river flooding on the non-linear interactions. The transition zone of damping and enhancing effects shifted downstream as the river flow rate increased.

Sp phases from the transition zone between the upper and lower mantle

1980 ◽  
Vol 70 (2) ◽  
pp. 487-508
Author(s):  
Sonja Faber ◽  
Gerhard MÜller
Keyword(s):  
United States ◽  
Transition Zone ◽  
Lower Mantle ◽  
The United States ◽  
P Wave ◽  
Western United States ◽  
Nodal Plane ◽  
Transition Zones ◽  
Velocity Models ◽  
Long Period

abstract Precursors to S and SKS were observed in long-period SRO and WWSSN seismograms of the Romanian earthquake of March 4, 1977, recorded in the United States at distances from 68° to 93°. According to the fault-plane solution, the stations were close to a nodal plane and SV radiation was optimum in their direction. Particle-motion diagrams, constructed from the digital data of the SRO station ANMO (distance 89.1°), show the P-wave character of the precursors. Several interpretations are discussed; the most plausible is that the precursors are Sp phases generated by conversion from S to P below the station. The travel-time differences between S or SKS and Sp are about 60 sec and indicate conversion in the transition zone between the upper and lower mantle. Sp conversions were also observed at long-period WWSSN stations in the western United States for 2 Tonga-Fiji deep-focus earthquakes (distances from 82° to 96°). Special emphasis is given in this paper to the calculation of theoretical seismograms, both for Sp precursors and the P-wave coda, including high-order multiples such as sP4 which may arrive simultaneously with Sp. The Sp calculations show: (1) the conversions produced by S, ScS, and SKS at interfaces or transition zones between the upper and lower mantle form a complicated interference pattern, and (2) conversion at transition zones is less effective than at first-order discontinuities only if their thickness is greater than about half a wavelength of S waves. As a consequence, details of the velocity structure between the upper and lower mantle can only be determined within these limits from long-period Sp observations. Our observations are compatible with velocity models having pronounced transition zones at depths of 400 and 670 km as have been proposed for the western United States, and they exclude much smoother structures. Our study suggests that long-period Sp precursors from pure thrust or normal-fault earthquakes, observed at distances from 70° to 95° close to a nodal plane and at azimuths roughly perpendicular to its strike, offer a simple means for qualitative mapping of the sharpness of the transition zones between the upper and lower mantle.

scholarly journals Coastal Resilience Against Storm Surge from Tropical Cyclones

Atmosphere ◽  
2020 ◽  
Vol 11 (7) ◽  
pp. 725
Author(s):  
Robert Mendelsohn ◽  
Liang Zheng
Keyword(s):  
United States ◽  
Probability Distribution ◽  
Tropical Cyclones ◽  
Storm Surge ◽  
Urban Areas ◽  
Storm Surges ◽  
The United States ◽  
Atlantic Seaboard ◽  
Order Of Magnitude ◽  
Coastal Resilience

It is well known that seawalls are effective at stopping common storm surges in urban areas. This paper examines whether seawalls should be built to withstand the storm surge from a major tropical cyclone. We estimate the extra cost of building the wall tall enough to stop such surges and the extra flood benefit of this additional height. We estimate the surge probability distribution from six tidal stations spread along the Atlantic seaboard of the United States. We then measure how valuable the vulnerable buildings behind a 100 m wall must be to justify such a tall wall at each site. Combining information about the probability distribution of storm surge, the average elevation of protected buildings, and the damage rate at each building, we find that the value of protected buildings behind this 100 m wall must be in the hundreds of millions to justify the wall. We also examine the additional flood benefit and cost of protecting a km2 of land in nearby cities at each site. The density of buildings in coastal cities in the United States are generally more than an order of magnitude too low to justify seawalls this high. Seawalls are effective, but not at stopping the surge damage from major tropical cyclones.

scholarly journals Predicting Major Storm Surge Levels

Atmosphere ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 756
Author(s):  
Robert Mendelsohn
Keyword(s):  
United States ◽  
Probability Distribution ◽  
Storm Surge ◽  
East Coast ◽  
The United States ◽  
Coastal Flooding ◽  
Southeast United States ◽  
Tidal Data ◽  
Major Hurricane

The National Atmospheric and Oceanic Administration (NOAA) calculates the surge probability distribution along the coast from their long-term tidal stations. This process is sufficient for predicting the surge from common storms but tends to underestimate large surges. Across 23 long-term tidal stations along the East Coast of the United States, 100-year surges were observed 49 times, although they should have occurred only 23 times. We hypothesize that these 100-year surges are not the tail outcome from common storms but are actually caused by major hurricanes. Matching these 100-year surges with major hurricanes revealed that major hurricanes caused 43 of the 49 surges. We consequently suggest a revised approach to estimating the surge probability distribution. We used tidal data to estimate the probability of common surges but analyzed major hurricane surges separately, using the return rate of major hurricanes and the observed surge from each major hurricane to predict hurricane surges. The revision reveals that expected coastal flooding damage is higher than we thought, especially in the southeast United States.

scholarly journals THE MARCH 1962 STORM ON THE ATLANTIC COAST OF THE UNITED STATES

2011 ◽  
Vol 1 (8) ◽  
pp. 32
Author(s):  
M.P. O'Brien ◽  
J.W. Johnson
Keyword(s):  
United States ◽  
New England ◽  
Storm Surge ◽  
Atlantic Coast ◽  
Large Diameter ◽  
The United States ◽  
Storm Damage ◽  
Southern New England ◽  
Cape Hatteras ◽  
Moving Storm

As far back as 1635, records show that the East Coast of the United States has repeatedly suffered from severe storm damage (McAleer , 1962). Most of these storms appear to have been of the hurricane type. Such storms generally form in the Atlantic to the east of the Bahama Islands and move eastward and then turn northward to sweep along the Atlantic Coast line (Fig. 1). Along the southern part of the Atlantic Coast the hurricanes move relatively slowly; damage results principally from flooding caused by direct wind action. North of Cape Hatteras the hurricanes move more rapidly (speeds of 40 to 50 miles per hour) and damage is largely due to sudden flooding from a rapidly moving storm surge (Simpson, 1962). The combination of storm surge, wind-driven water, and storm waves inundating large areas along the coast has on numerous occasions caused great damage and loss of life. The great Atlantic Coast storm of March 1962, however, differed in character from the usual hurricane. It proved to be the most disastrous winter coastal storm on record, causing damage from southern New England to Florida. This storm, of relatively large diameter and having gale force winds, remained nearly stationary off the Coast for almost 36 hours . The size and location of the storm, as further discussed below, was such that persistent strong northeasterly winds blowing over a relatively long fetch raised the spring tides (maximum range) to near-record levels. The tidal flooding which attended this storm was in many ways more disastrous than that which accompanies hurricanes (Cooperman and Rosendal, 1962). The storm surge in tropical cyclones generally recedes rapidly after one or two high tides, but the surge accompanying this storm occurred in many locations on four and five successive high tides .' The great destruction was caused by high waves and breakers superimposed on these high tides.

scholarly journals Visualization of Lake Mead Surface Area Changes from 1972 to 2009

2021 ◽  
Author(s):  
K. Wayne Forsythe ◽  
Barbara Schatz ◽  
Stephen J. Swales ◽  
Lisa-Jen Ferrato ◽  
David M. Atkinson
Keyword(s):  
United States ◽  
Water Level ◽  
Surface Area ◽  
Satellite Images ◽  
Strong Relationship ◽  
The United States ◽  
Water Levels ◽  
Lake Area ◽  
Lake Mead ◽  
Landsat Satellite

For most of the last decade, the south-western portion of the United States has experienced a severe and enduring drought. This has caused serious concerns about water supply and management in the region. In this research, 30 orthorectified Landsat satellite images from the United States Geological Service (USGS) Earth Explorer archive were analyzed for the 1972 to 2009 period. The images encompassed Lake Mead (a major reservoir in this region) and were examined for changes in water surface area. Decadal lake area minimums/maximums were achieved in 1972/1979, 1981/1988, 1991/1998, and 2009/2000. The minimum lake area extent occurred in 2009 (356.4 km2), while the maximum occurred in 1998 (590.6 km2). Variable trends in water level and lake area were observed throughout the analysis period, however progressively lower values were observed since 2000. The Landsat derived lake areas show a very strong relationship with actual measured water levels at the Hoover Dam. Yearly water level variations at the dam vary minimally from the satellite derived estimates. A complete (yearly) record of satellite images may have helped to reduce the slight deviations in the time series.

scholarly journals Automated Water Level Monitoring at the Continental Scale from ICESat-2 Photons

2021 ◽  
Vol 13 (18) ◽  
pp. 3631
Author(s):  
Austin Madson ◽  
Yongwei Sheng
Keyword(s):  
United States ◽  
Water Level ◽  
Cluster Computing ◽  
Mean Squared Error ◽  
The United States ◽  
United States Geological Survey ◽  
Continental Scale ◽  
Water Level Changes ◽  
Lakes And Reservoirs ◽  
The Mean

Of the approximately 6700 lakes and reservoirs larger than 1 km2 in the Contiguous United States (CONUS), only ~430 (~6%) are actively gaged by the United States Geological Survey (USGS) or their partners and are available for download through the National Water Information System database. Remote sensing analysis provides a means to fill in these data gaps in order to glean a better understanding of the spatiotemporal water level changes across the CONUS. This study takes advantage of two-plus years of NASA’s ICESat-2 (IS-2) ATLAS photon data (ATL03 products) in order to derive water level changes for ~6200 overlapping lakes and reservoirs (>1 km2) in the CONUS. Interactive visualizations of large spatial datasets are becoming more commonplace as data volumes for new Earth observing sensors have markedly increased in recent years. We present such a visualization created from an automated cluster computing workflow that utilizes tens of billions of ATLAS photons which derives water level changes for all of the overlapping lakes and reservoirs in the CONUS. Furthermore, users of this interactive website can download segmented and clustered IS-2 ATL03 photons for each individual waterbody so that they may run their own analysis. We examine ~19,000 IS-2 derived water level changes that are spatially and temporally coincident with water level changes from USGS gages and find high agreement with our results as compared to the in situ gage data. The mean squared error (MSE) and the mean absolute error (MAE) between these two products are 1 cm and 6 cm, respectively.

scholarly journals Modeling the COVID-19 pandemic - parameter identification and reliability of predictions

2020 ◽  
Author(s):  
Klaus Hackl
Keyword(s):  
United States ◽  
Linear Regression ◽  
South Korea ◽  
Parameter Identification ◽  
The United States ◽  
Epidemic Models ◽  
Non Linear ◽  
The Future ◽  
History Of ◽  
Using Data

AbstractIn this paper, we try to identify the parameters for two elementary epidemic models, the so-called SI- and SIS-models, via non-linear regression using data of the COVID-19 pandemic. This is done based on the data for the number of daily infections. Studying the history of predictions made, we attempt to estimate their reliability concerning the future course of the epidemic. We validate this procedure using data for the case numbers in China and South Korea. Then we apply it in order to find predictions for Germany, Italy and the United States. The results are encouraging, but no final judgment on the validity of the procedure can yet be made.

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