Joel Rowland | Los Alamos National Laboratory (original) (raw)

Papers by Joel Rowland

Water resources research, 2014

Landscape attributes that vary with microtopography, such as active layer thickness (ALT), are la... more Landscape attributes that vary with microtopography, such as active layer thickness (ALT), are labor intensive and difficult to document effectively through in situ methods at kilometer spatial extents, thus rendering remotely sensed methods desirable. Spatially explicit estimates of ALT can provide critically needed data for parameterization, initialization, and evaluation of Arctic terrestrial models. In this work, we demonstrate a new approach using high-resolution remotely sensed data for estimating centimeter-scale ALT in a 5 km(2) area of ice-wedge polygon terrain in Barrow, Alaska. We use a simple regression-based, machine learning data-fusion algorithm that uses topographic and spectral metrics derived from multisensor data (LiDAR and WorldView-2) to estimate ALT (2 m spatial resolution) across the study area. Comparison of the ALT estimates with ground-based measurements, indicates the accuracy (r(2) = 0.76, RMSE ±4.4 cm) of the approach. While it is generally accepted that...

2007 AAPG Annual Convention and Exhibition, 2007

Hydrogeology Journal, 2013

The value of remote sensing and surface geophysical data for characterizing the spatial variabili... more The value of remote sensing and surface geophysical data for characterizing the spatial variability and relationships between land-surface and subsurface properties was explored in an Alaska (USA) coastal plain ecosystem. At this site, a nested suite of measurements was collected within a region where the land surface was dominated by polygons, including: LiDAR data; groundpenetrating radar, electromagnetic, and electrical-resistance tomography data; active-layer depth, soil temperature, soil-moisture content, soil texture, soil carbon and nitrogen content; and pore-fluid cations. LiDAR data were used to extract geomorphic metrics, which potentially indicate drainage potential. Geophysical data were used to characterize active-layer depth, soil-moisture content, and permafrost variability. Cluster analysis of the LiDAR and geophysical attributes revealed the presence of three spatial zones, which had unique distributions of geomorphic, hydrological, thermal, and geochemical properties. The correspondence between the LiDAR-based geomorphic zonation and the geophysics-based active-layer and permafrost zonation highlights the significant linkage between these ecosystem compartments. This study suggests the potential of combining LiDAR and surface geophysical measurements for providing high-resolution information about land-surface and subsurface properties as well as their spatial variations and linkages, all of which are important for quantifying terrestrial-ecosystem evolution and feedbacks to climate.

Geophysical Research Letters, 2011

Long-term lake area change has previously been measured to detect the temporal rate and spatial e... more Long-term lake area change has previously been measured to detect the temporal rate and spatial extent of permafrost degradation. However, the natural intra-and interannual variability of lake areas has not been considered explicitly and quantitatively, which can substantially interfere with the detection of long-term lake area change associated with permafrost degradation. In order to better understand the natural background variability of lake areas,

Journal of Geophysical Research: Earth Surface, 2014

In the absence of strong wave or tide, two distinct river mouth morphologies are present on delta... more In the absence of strong wave or tide, two distinct river mouth morphologies are present on deltas: bifurcating channels that form branching networks, and elongate channels exhibiting little or no bifurcation. Recent numerical and experimental studies have reproduced these channel patterns, but have not related them clearly to hydrodynamic controls. Here we develop a generalized two-dimensional potential vorticity (PV) method,

Journal of Geophysical Research, 2010

1] Levee formation by deposition from sediment-laden flows debouching into open waters has been c... more 1] Levee formation by deposition from sediment-laden flows debouching into open waters has been conceptually and analytically linked to jet hydrodynamics since the middle of the 20th century. Despite this long-standing association between jets and levees, the morphodynamics controlling subaqueous levee development remain largely unquantified and poorly understood. Here we report the results of physical experiments on subaqueous levee development modeled on floodplain tie channel processes. In the laboratory, we created subaqueous levees from a sediment-laden jet entering a basin of still water. Levee formation occurred where the local shear velocity of the jet declined below the critical shear velocity for entrainment of sediment into suspension. The rate of levee deposition depended on the rate of lateral sediment transfer to the jet margins and the settling velocity of suspended sediment. In our friction-dominated flows, lateral sediment flux to the levees was primarily due to dispersive lateral transport driven by turbulence. High rates of sediment transfer from the jet core to the margins led to levee growth that outpaced deposition along the flow centerline. Under hypopycnal conditions, we failed to produce levees. We observed distinct differences in levee morphology due to changes in the size and density of suspended sediment under identical hydrodynamic conditions. Our experimental results and review of published data on hypopycnal river mouths suggest that suspended sediment characteristics, relative magnitude of bed friction, and channel outlet aspect ratios may have a more significant influence on river mouth morphology than the buoyancy of discharging waters as envisioned in existing conceptual models. Citation: Rowland, J. C., W. E. Dietrich, and M. T. Stacey (2010), Morphodynamics of subaqueous levee formation: Insights into river mouth morphologies arising from experiments,

Journal of Fluid Mechanics, 2009

Jets arising from rivers, streams and tidal flows entering still waters differ from most experime... more Jets arising from rivers, streams and tidal flows entering still waters differ from most experimental studies of jets both in aspect ratio and in the presence of a solid bottom boundary and an upper free surface. Despite these differences, the applicability of experimental jet studies to these systems remains largely untested by either field or realistically scaled experimental studies. Here we present experimental results for a wall-bounded plane jet scaled to jets created by flow discharging into floodplain lakes. A characteristic feature of both our prototype and experimental jets is the presence of large-scale meandering turbulent structures that span the width of the jets. In our experimental jets, we observe self-similarity in the distribution of mean streamwise velocities by a distance of six channel widths downstream of the jet outlet. After a distance of nine channel widths the velocity decay and the spreading rates largely agree with prior experimental results for plane jets. The magnitudes and distributions of the cross-stream velocity and lateral shear stresses approach self-preserving conditions in the upper half of the flow, but decrease in magnitude, and deviate from self-preserving distributions with proximity to the bed. The presence of the meandering structure has little influence on the mean structure of the jet, but dominates the jet turbulence. A comparison of turbulence analysed at time scales both greater than and less than the period of the meandering structure indicates that these structures increase turbulence intensities by 3-5 times, and produce lateral shear stresses and momentum diffusivities that are one and two orders of magnitude greater, respectively, than turbulence generated by bed friction alone.

Geofluids, 2009

The origins of increased stream flow and spring discharge following earthquakes have been the sub... more The origins of increased stream flow and spring discharge following earthquakes have been the subject of controversy, in large part because there are many models to explain observations and few measurements suitable for distinguishing between hypotheses. On October 30, 2007 a magnitude 5.5 earthquake occurred near the Alum Rock springs, California, USA. Within a day we documented a several-fold increase in discharge. Over the following year, we have monitored a gradual return towards pre-earthquake properties, but for the largest springs there appears to be a permanent increase in discharge. The Alum Rock springs discharge waters that are a mixture between modern (shallow) meteoric water and old (deep) connate waters expelled by regional transpression. After the earthquake, there was a small and temporary decrease in the fraction of connate water in the largest springs. Accompanying this geochemical change was a small (1-2°C) temperature decrease. Combined with the rapid response, this implies that the increased discharge has a shallow origin. Increased discharge at these springs occurs both for earthquakes that cause static volumetric expansion and for those that cause contraction, supporting models in which dynamic strains are responsible for the subsurface changes that cause flow to increase. We make a quantitative comparison between the observed changes and model predictions for three types of models: (i) a permanent increase in permeability; (ii) an increase in permeability followed by a gradual decrease to its preearthquake value; and (iii) an increase of hydraulic head in the groundwater system discharging at the springs. We show that models in which the permeability of the fracture system feeding the springs increases after the earthquake are in general consistent with the changes in discharge. The postseismic decrease in discharge could either reflect the groundwater system adjusting to the new, higher permeability or a gradual return of permeability to pre-earthquake values; the available data do not allow us to distinguish between these two scenarios. However, the response of these springs to another earthquake will provide critical constraints on the changes that occur in the subsurface and should permit a test of all three types of models.

Geofluids, 2008

Thermal springs commonly occur along faults because of the enhanced vertical permeability afforde... more Thermal springs commonly occur along faults because of the enhanced vertical permeability afforded by fracture zones. Field and laboratory studies of fault zone materials document substantial heterogeneities in fracture permeabilities. Modeling and field studies of springs suggest that spatial variations in permeability strongly influence spring locations, discharge rates and temperatures. The impact of heterogeneous permeability on spring geochemistry, however, is poorly documented. We present stable isotope and water chemistry data from a series of closely spaced thermal springs associated with the Hayward Fault, California. We suggest that substantial spatial variations observed in d 18 O and chloride values reflect subsurface fluid transport through a poorly connected fracture network in which mixing of subsurface waters remains limited. Our measurements provide insight into the effect of fracture zone heterogeneities on spring geochemistry, offer an additional tool to intuit the nature of tectonically induced changes in fault zone plumbing, and highlight the need to consider local variations when characterizing fracture zone fluid geochemistry from spring systems with multiple discharge sites.

Developments in Earth and Environmental Sciences, 2008

... 3, Andrew Marshall &amp;amp;amp; Associates Pty Ltd., 43 Warrangarree Drive, Woronora... more ... 3, Andrew Marshall &amp;amp;amp; Associates Pty Ltd., 43 Warrangarree Drive, Woronora Heights, New South Wales 2233, Australia. ... The detailed GPS and aerial survey work for this project was performed by Andrew Marshall &amp;amp;amp; Associates, Sydney, Australia. ...

Journal of Sedimentary Research, 2010

... Research Articles: Submarine Deposition. A Test of Initiation of Submarine Leveed Channels by... more ... Research Articles: Submarine Deposition. A Test of Initiation of Submarine Leveed Channels by Deposition Alone. Joel C. Rowland 1 , George E. Hilley 2 and Andrea Fildani 3 ... Excess density of the inflow was provided by dissolving Cargill &amp;quot;top-flo&amp;quot; evaporated salt in tap water. ...

Marine and Petroleum Geology, 2013

We present a general model for channel inception and evolution in the deep sea by integrating obs... more We present a general model for channel inception and evolution in the deep sea by integrating observations from two complementary datasets: (1) high-resolution.

ABSTRACT In simple models of lowland river systems, water and sediment enter the main stem via tr... more ABSTRACT In simple models of lowland river systems, water and sediment enter the main stem via tributary and secondary channels and are only redistributed to the floodplain during overbank and crevasse splay events. Along numerous river systems across the globe, however, water and sediment are regularly exchanged between the river and off river water bodies via stable, narrow channels. These channels, known as tie channels on the Fly River in Papua New Guinea and batture channels along the lower Mississippi, are largely overlooked but important components of floodplain sediment dispersal where they exist. These channels become pathways of sediment dispersal to the floodplain system when elevated river stages force sediment-laden flows into the off-river water bodies. On the Fly River, it is estimated that about 50% of the sediment delivery to the floodplain is via these channels, and along low gradient tributary channels during flood driven flow reversals. During low flow, tie channels serve to drain the floodplain. With the outgoing flows, large amounts sediment can be carried and lost to the floodplain; floodplain lakes progressively infill with sediment as the mouth of these channels steadily prograde lakeward. These lake deposits not only become significant stratigraphic components of floodplains (traditionally referred to as clay plugs), but are important local sinks recording hundreds to thousands of years of river history. As with all sinks, the proper interpretation of these stratigraphic records requires understanding the processes by which sediment is delivered to the sink and how these processes alter the paleohydraulic and climatic signals of interest. We have conducted field investigations of conjoining channels in Papua New Guinea (the Fly and Strickland Rivers), Louisiana (Raccourci Old River ~ 65 km upriver of Baton Rouge) and Alaska (Birch Creek). These field investigations include extensive surveys of both cross and along channel morphological trends, grain size characteristics, water levels and geochronological sampling using optically stimulated luminescence (OSL). Across all systems channel morphology is similar and exhibit scale independence, however, channel size and rates of progradation are directly related to the size of the main stem river. Through these studies and ongoing scaled modeling we are examining the morphodynamics that lead to the formation, advancement and stability of these unique self formed channels.

Permafrost and Periglacial Processes, 2013

ABSTRACT Long‐term lake area change has previously been measured to detect the temporal rate and ... more ABSTRACT Long‐term lake area change has previously been measured to detect the temporal rate and spatial extent of permafrost degradation. However, the natural intra‐ and interannual variability of lake areas has not been considered explicitly and quantitatively, which can substantially interfere with the detection of long‐term lake area change associated with permafrost degradation. In order to better understand the natural background variability of lake areas, we used Landsat 7 images obtained on 11 dates from 1999 to 2002 to quantify the intra‐ and interannual lake area variability for a 4224 km2 study area within the Yukon Flats, Alaska. Total lake areas ranged from 179 km2 (22 August 1999) to 326 km2 (6 June 2000). Even within a single year (year 2000), the total lake area decreased by 42 per cent from 6 June to 16 August, well exceeding the previously reported trends for long‐term decrease (14% and 18%) for the Yukon Flats. Both intra‐ and interannual area variability in August and September were smaller than in June and July, suggesting that images from later in summer are more reliable for detecting long‐term change in lake area. Variability of no‐closure lakes was twice that of closed‐basin lakes. Intra‐annual area changes in closed‐basin lakes can be explained by the intra‐annual water balance, defined as cumulative precipitation minus evaporation between two consecutive dates within the same year. For a given period, the total lake area was correlated more strongly with the water balance since the preceding October than with the water balance in the preceding 12 months. Spatial heterogeneity in the intra‐annual area change of individual lakes was observed, which might be caused by different topographical, geological and permafrost characteristics around and beneath the lakes. Copyright © 2013 John Wiley & Sons, Ltd.

ABSTRACT The formation, expansion, and drainage of thermokarst lakes is determined by the lateral... more ABSTRACT The formation, expansion, and drainage of thermokarst lakes is determined by the lateral and vertical degradation of permafrost. Consequently, areal changes in thermokarst lakes can reflect changes in the spatial distribution and depth of permafrost. However, natural variability in lake areas confounds the long term trend and makes it difficult to detect permafrost degradation by simply comparing lake areas from different time periods. In this study, we used Landsat images of 16 time periods between 1984 and 2009 to extract lake area (closed basin lakes only) for a 422,382 ha study area within Yukon Flats, Alaska. A multiple linear regression model was built to quantify the long term change in lake area. In this model, we included LWB (local water balance, defined as difference between total precipitation and total potential evapotranspiration since the preceding October), MDT (mean daily temperature from May 1st to the date that Landsat image was acquired) and PRD (four time periods: 1984-1986, 1992, 1999-2002, and 2009). MDT was used to indicate the active layer depth. Both LWB and MDT were used to account for natural variability in lake area. The model explained 95% of the total variability in lake area, with 62%, 16% and 17% accounted for by LWB, MDT and PRD respectively. Using the total lake area (15898 ha) in 1984-1986 as a baseline, lake area increased by 12% in 1992, and decreased by 6% during 1999-2002 and 8% in 2009. Among the 1,667 lakes, 267 lakes showed an area decrease and 115 lakes showed an increase. The expanding lakes were distributed along the Yukon River and its main tributaries (Beaver creek and Birch creek), while the shrinking lakes were located farther away from rivers or on fluvial terraces. A potential reason for the spatial pattern of expanding and shrinking lakes is that, after permafrost thaws, lakes can become connected to the groundwater system. Lakes close to the rivers may be recharged by groundwater due to their lower position relative to groundwater table, while lakes farther away from rivers drain to the subsurface due to their higher position. This study provides a rigorous method to quantify long term change in thermokarst lake area and the regression model can be used in earth system models to make better predictions of thermokarst lake areas.

In this letter, we present a semi-automated approach to identify and classify Arctic polygonal tu... more In this letter, we present a semi-automated approach to identify and classify Arctic polygonal tundra landscape components, such as troughs, ponds, rivers and lakes, using high spatial resolution satellite imagery. The approach starts by segmenting water bodies from an image, which are then categorized using shape-based classification. Segmentation uses combination of multispectral bands and is based on the active contours without edges technique. The segmentation is robust to noise and can detect objects with weak boundaries, which is important for the extraction of troughs. Classification of the regions is accomplished by utilizing distance transform and regional structural characteristics. The approach is evaluated using 0.6 m resolution WorldView-2 satellite image of ice-wedge polygonal tundra. The segmentation user's and producer's accuracies are approximately 92% and 97%, respectively. Visual inspection of the classification results has demonstrated qualitatively accurate object categorization.