Jenna Brown

United States Geological Survey | USGS · St. Petersburg Coastal and Marine Science Center

Barrier islands are especially vulnerable to hurricanes and other large storms, owing to their mobile composition, low elevations, and detachment from the mainland. Conceptual models of barrier‐island evolution emphasize ocean‐side processes that drive landward migration through overwash, inlet migration, and aeolian transport. In contrast, we foun...

Unoccupied aerial systems can collect aerial imagery that can be used to develop structure-from-motion products with a temporal resolution well-suited to monitoring dynamic barrier island environments. However, topographic data created using photogrammetric techniques such as structure-from-motion represent the surface elevation including the veget...

The Surf-camera Remote Calibration Tool (SurfRCaT) is a Python-based software application to calibrate and rectify images from pre-existing video cameras that are operating at coastal sites in the United States. The software enables remote camera calibration and subsequent image rectification by facilitating the remote-extraction of ground control...

Web cameras are transforming coastal environmental monitoring. Improvements in camera technology and image processing capabilities, paired with decreases in cost, enable widespread use of camera systems by researchers, managers and first responders for a growing range of environmental monitoring applications. Applications are related to transportat...

Surfzone mixing and transport on a sandy, steep (∼1/8 slope), reflective beach at Carmel River State Beach, California, are described for a range of wave and alongshore flow conditions. Depth-limited wave breaking occurred close to the shore due to the steepness of the beach, creating a narrow surf/swash zone (∼10 m wide). Fluorescent Rhodamine dye...

Video measurements of runup were collected at low tide along several profiles covering an alongshore distance of 500 m. The morphology displayed a complex shape with a shoreline sandwave in the lower beach face of about 250 m long mirrored in the inner sandbar. Wave conditions were stationary and moderate (offshore height of 2 m and peak period of...

Surf zones, regions of breaking waves, are at the interface between the shore and coastal ocean. Surf zone hydrodynamics may affect delivery of phytoplankton subsidies to the intertidal zone. Over a month of daily sampling at an intermediate surf zone with bathymetric rip currents and a reflective surf zone, we measured surf zone hydrodynamics and...

Larvae of intertidal species develop at sea and must return to adult habitats to replenish populations. Similarly, nutrients, detritus and plankton provide important subsidies spurring growth and reproduction of macroalgae and filter-feeding invertebrates that form the foundation of intertidal communities. Together, these factors determine the dens...

Most harmful algal blooms (HAB) originate away from the shore and, for them to endanger human health, they must be first transported to shore after which they must enter the surf zone where they can be feed upon by filter feeders. The last step in this sequence, entrance into the surf zone, depends on surf zone hydrodynamics. During two 30-day peri...

Cross-shore exchange between the surf zone and the inner shelf is investigated using Lagrangian and Eulerian field measurements of rip current flows on a rip-channeled beach in Sand City, California. Surface drifters released on the inner shelf during weak wind conditions moved seaward due to rip current pulses and then returned shoreward in an arc...

Larvae of many intertidal species develop offshore and must cross the surf zone to complete their onshore migration to adult habitats. Depending on hydrodynamics, the surf zone may limit this migration, especially on reflective rocky shores. As a logistically tractable analog of a rocky shore environment, we carried out a comprehensive biological a...

Background/Question/Methods The ability of microscopic larvae to replenish populations in dynamic marine environments has been a long-running topic of debate for regulating marine communities. The discovery of a latitudinal difference in larval recruitment along the west coast of the USA in the 1980s stimulated a resurgence of interest in the eff...

Identifying biophysical mechanisms of larval transport is essential to understanding the delivery of larvae to adult habitats. In addition, harmful algal blooms (HABs) can be transported onshore from populations that form offshore. In summer 2011, we measured sea surface and bottom temperatures and daily phytoplankton abundance and intertidal cypri...

Rip currents are the primary hazard on surf beaches, and early studies described them as fast, shore-normal flows that extended seaward of the surf zone. Based on this traditional view, commonly promoted safety advice was to escape a rip current by swimming parallel to the beach. However, recent studies have shown dominant rip current re-circulatio...

Novel observations of surface grain-size distributions are used in combination with intra-wave modeling to examine the processes responsible for the sorting of sediment grains on a relatively steep beach (slope = 1:7.5). The field observations of the mean grain size collected with a digital camera system at consecutive low and high tides for a 2 we...

Rip flow dynamics have important implications for swimmer escape strategies, with recent field studies indicating flow is often contained within the surf zone, re-circulating onto shallow bars. Combining physical measurements in a variety of conditions with various escape strategies allows insights into the safest response by individuals caught in...

A sequence of daily beach surveys acquired over one month covering an area larger than 100,000 m2, was analyzed to study morphological changes resulting from a cluster of storms. The beach response was highly variable in both the cross- and alongshore. A cumulative storm effect was not observed, despite one storm being characterized by a 10-year re...

Applying a two-dimensional (2D) divergence-free (DF) interpolation to a one-person deployable unmanned underwater vehicle's (UUV) noisy moving-vessel acoustic Doppler current profiler (MV-ADCP) measurements improves the results and increases the utility of the UUV in tidal environments. For a 3.5-h MV-ACDP simulation that spatially and temporally v...

Autonomous vehicles (AVs) are commonly used in oceanic and more recently estuarine and riverine environments because they are small, versatile, efficient, moving platforms equipped with a suite of instruments for measuring environmental conditions. However, moving vessel observations, particularly those associated with Acoustic Doppler Current Prof...

Grain size is an important variable when predicting beach morphodynamics. Beaches, to the eye, seem relatively uniform in grain size and morphodynamic modeling efforts usually assume a single mean grain size for an entire beach environment. Therefore, estimating grain size is traditionally done by collecting only a few samples and averaging to char...

Rip currents are fascinating, natural, surf zone phenomena that occur daily on many beaches throughout the world. My colleagues, students, advisors, and I have been studying rip currents for more than 10 years and have performed more than 10 comprehensive field experiments on various beaches throughout the world using different observational techni...

A field experiment was conducted on a high energy macro-tidal beach (Perranporth, UK) to examine rip current dynamics over a low-tide transverse bar/rip system in response to changing tide and wave conditions. Hydrodynamic data were collected using an array of in situ acoustic doppler current meters and pressure transducers, as well as 12 GPS-track...

The accepted view of rip currents is that they are an efficient mechanism for transporting material out of the surf zone. Previous rip current campaigns on natural beaches have focused on Eulerian measurements with sparse in situ pressure and current meter arrays. Here, for the first time, spatially synoptic estimates of rip current flow patterns,...

The retention of floating matter within the surf zone on a rip-channeled beach is examined with a combination of detailed field observations obtained during the Rip Current Experiment and a three-dimensional (3-D) wave and flow model. The acoustic Doppler current profiler–observed hourly vertical cross-shore velocity structure variability over a pe...

The macrotidal intermediate-dissipative beaches of the southwest UK display strong seasonality whereby extensive low-tide bar/rip systems form during the spring season. These features reach a state of maximum development during the summer months, when strong rip currents are present at various stages of the tide that switch on/off due to tidal tran...

The RCEX experiment, conducted in Monterey in 2007, provided a detailed look at rip current circulation over a bathymetry consisting of persistent shoals and rip channels. The experiment employed a large fleet of GPS drifters to map mean flows and to develop one and two-point dispersion statistics, and revealed flow patterns ranging from closed rec...