Publications and Presentations

Satellite-based field delineation has entered a quasi-operational stage due to recent advances in machine learning for computer vision. …

Zoning regulates land use and intensity of urban development at the county and municipal level in the United States, promoting economic …

The risk of floods from tropical storms is increasing due to climate change and human development. Maps of past flood extents can aid …

Changes in climate and land-use/land-cover will impact surface water dynamics throughout the 21st century and influence global surface …

We developed a novel framework to map boro rice at peak season using Sentinel images. These Boro rice maps in Bangladesh showed high classification accuracy (mean of 87.90%). There was no requirement of sample data collection for training the classification model. Multi-Otsu effectively maps rice in low-data areas, outperforming other ML methods and provides stakeholders rice area statistics to support food security management.

Satellite as well as reanalysis-based datasets are widely available and useful in detecting spatial and temporal variability of …

People and the environment rely on water to exist and thrive, especially water on the Earth’s surface because that is the easiest place to get it. The amount of surface water and where it is located is changing with the climate and changes in people’s water use, and our need for it is increasing. To plan ahead for future water needs, we need to better understand how the climate and people are changing surface water patterns both separately and together. To help improve our understanding of these changes, we modeled the amount of surface water in three different ways. First, we modeled based on climate data (like temperature and precipitation); second, based on human data (like land use and population); and third, based on both climate and human data together. We found that we could best model the amount of surface water if we used both climate and human data together, and that human data can explain a lot of the changes in the amount of surface water. These results mean that we can work to control changes in the amount of surface water by controlling human actions through planning and policies.

Key to understanding forest water balances is the role of tree species regulating evapotranspiration (ET), but the synergistic impact …

Spatiotemporal quantification of surface water and flooding is essential given that floods are among the largest natural hazards. …

Fresh water stored by on-farm reservoirs (OFRs) is an important component of surface hydrology and is critical for meeting global …

Unprecedented amounts of analysis-ready Earth Observation (EO) data, combined with increasing computational power and new algorithms, …

Basemap and Planet Fusion—derived from PlanetScope imagery—represent the next generation of analysis ready datasets that minimize the …

Floods are the largest natural hazard in terms of life loss and economic damage, regardless of their cause. In the United States alone, …

During the 21st century, human–environment interactions will increasingly expose both systems to risks, but also yield opportunities …

Accurate estimation of land surface states is critical for improving prediction of coupled global weather and climate forecast systems, …

On-farm reservoirs (OFRs)—artificial water impoundments that retain water from rainfall and run-off—enable farmers to store water during the wet season to be used for crop irrigation during the dry season. However, monitoring the inter- and intra-annual change of these water bodies remains a challenging task because they are typically small (< 10 ha) and occur in high numbers. Therefore, we used two existing Landsat inundation datasets—the U.S. Geological Survey Dynamic Surface Water Extent (DSWE) and the European Commission’s Joint Research Centre (JRC) Global Monthly Water History—to assess surface water area change of OFRs located in eastern Arkansas, the third most irrigated state in the U.S.

Water stress is a global concern as a changing climate leads to variations in weather patterns and agricultural and urban areas continue to use water-intensive practices. Understanding spatial and temporal factors of surface water dynamics is key to better managing our resources and limiting the effects of water stress

Floods, defined as water that temporarily submerges land for over 72 hours or longer, are the largest natural hazard in terms of life loss and economic damage. Effective and immediate disaster response management can reduce the impact of floods but it requires near real-time information on flood occurrence, typically derived based on Earth Observation data.

Geospatial analysis is crucial for addressing many of the world’s most pressing challenges. In this work, we explore this important intersection – between geospatial analytics and visualization – by examining a set of recent IEEE VIS Conference papers (a selection from 2017-2019) to assess the inclusion of geospatial data and geospatial analyses within these papers.

Landscape connectivity is increasingly promoted as a conservation tool to combat the negative effects of habitat loss, fragmentation, …

By influencing water tables of saline aquifers, multiyear dry or wet periods can significantly delay or accelerate dryland salinity, but this effect remains poorly quantified at the large river basin scale.

Detailed information on the number and density of trees is important for conservation and sustainable use of forest resources. In this respect, remote sensing technology is a reliable tool for deriving timely and fine-scale information on forest inventory attributes. However, to better predict and understand the functioning of the forest, fine-scale measures of tree number and density must be extrapolated to the forest plot or stand levels through upscaling.

Spatiotemporal distribution and systematic quantification of surface water and their drivers of change are critical. However, quantifying this distribution is challenging due to a lack of spatially explicit and temporally dynamic empirical data of both surface water and its drivers of change at large spatial scales.

Vegetation response to flooding across large dryland areas such as Australia’s Murray Darling Basin (MDB) is not understood synoptically and with locally relevant detail.

Recent studies have developed novel long-term records of surface water (SW) maps on continental and global scales but due to the spatial and temporal resolution constraints of available satellite sensors, they are either of high spatial and low temporal resolution or vice versa.

Afghanistan has only 11% of arable land while wheat is the major crop with 80% of total cereal planted area. The production of wheat is …

In dynamic dryland regions, accounting for spatiotemporal landscape dynamics is essential to understanding how ecological habitat networks are affected by hydroclimatic variability at regional or sub-continental scales. Here we assess how changes in the distribution and availability of surface water influence potential landscape connectivity for water-dependent organisms by combining graph theory network analysis with a Landsat-derived, seasonally continuous 25-year surface-water time-series.

Despite calls for landscape connectivity research to account for spatiotemporal dynamics, studies have overwhelmingly evaluated the importance of habitats for connectivity at single or limited moments in time. Remote sensing time series represent a promising resource for studying connectivity within dynamic ecosystems. However, there is a critical need to assess how static and dynamic landscape connectivity modelling approaches compare for prioritising habitats for conservation within dynamic environments.

Landscape-scale research quantifying ecological connectivity is required to maintain the viability of populations in dynamic …

Landscape connectivity is important for the long-term persistence of species inhabiting dryland freshwater ecosystems, with spatiotemporal surface-water dynamics (e.g., flooding) maintaining connectivity by both creating temporary habitats and providing transient opportunities for dispersal.

Periodically inundated floodplain areas are hot spots of biodiversity and provide a broad range of ecosystem services but have suffered alarming declines in recent history. Despite their importance, their long-term surface water (SW) dynamics and hydroclimatic drivers remain poorly quantified on continental scales.

Drought is a global issue that is exacerbated by climate change and increasing anthropogenic water demands. The recent occurrence of drought in California provides an important opportunity to examine drought response across ecosystem classes (forests, shrublands, grasslands, and wetlands), which is essential to understand how climate influences ecosystem structure and function.

Aquatic ecosystems are under threat from multiple stressors, which vary in distribution and intensity across temporal and spatial scales. Monitoring and assessment of these ecosystems have historically focussed on collection of physical and chemical information and increasingly include associated observations on biological condition

Declining forest health can affect crucial ecosystem functions, such as carbon storage in biomass and soils, the regulation of water regimes, the modulation of regional climate and conservation of biodiversity. Airborne laser scanning (ALS) and imaging spectroscopy (IS) are two potentially complementary remote sensing technologies capable of characterizing and monitoring regional forest health.

The usage of time series of Earth observation (EO) data for analyzing and modeling surface water extent (SWE) dynamics across broad geographic regions provides important information for sustainable management and restoration of terrestrial surface water resources, which suffered alarming declines and deterioration globally.

Full-waveform airborne laser scanning (ALS) is a powerful tool for characterizing and monitoring forest structure over large areas at the individual tree level. Most of the existing ALS-based algorithms for individual tree delineation from the point cloud are top-down, which are accurate for delineating cone-shaped conifers, but have lower delineation accuracies over more structurally complex broad-leaf forests.

Seasonally continuous long-term information on surface water and flooding extent over subcontinental scales is critical for quantifying spatiotemporal changes in surface water dynamics. We used seasonally continuous Landsat TM/ETM + data and generic random forest-based models to synoptically map the extent and dynamics of surface water and flooding (1986–2011) over the Murray–Darling Basin (MDB).

Multispectral remote sensing (MSS) sensors have been generally utilized for acquiring and extracting information of Land Use Land …

Land surface phenology (LSP) characterizes episodes of greening and browning of the vegetated land surface from remote sensing imagery. …

The concept of habitat networks represents an important tool for landscape conservation and management at regional scales. Previous studies simulated degradation of temporally fixed networks but few quantified the change in network connectivity from disintegration of key features that undergo naturally occurring spatiotemporal dynamics.

Detailed information on the spatiotemporal dynamic in surface water bodies is important for quantifying the effects of a drying …

Land surface phenological cycles of vegetation greening and browning are influenced by variability in climatic forcing. Quantitative …

The phenology of a landscape is a key parameter in climate and biogeochemical cycle models and its correct representation is central to …

Remote sensing techniques that provide synoptic and repetitive observations over large geographic areas have become increasingly …

Combining protected areas with natural forest timber concessions may sustain larger forest landscapes than is possible via protected …

Borneo Island is experiencing rapid tree-cover loss. This loss has been quantified for the Indonesian part of the island at Landsat …

Crop residue is potentially a major biomass feedstock for bio-based industries. Spatial and interannual variability of crop residue …

Detailed information on the spatiotemporal dynamic in surface water bodies is important for quantifying the effects of a drying climate, increased water abstraction and rapid urbanization on wetlands.

A climate envelope approach was used to model the response of switchgrass, a model bioenergy species in the United States, to future …

Nonnative Phragmites is among the most invasive plants in the U.S. Atlantic coast tidal wetlands, whereas the native Phragmites has …

Forest cover and forest cover loss for the last decade, 2000–2010, have been quantified for the Democratic Republic of the Congo (DRC) …

The U.S. Renewable Fuel Standard calls for 136 billion liters of renewable fuels production by 2022. Switchgrass (Panicum virgatum L.) …

Bushfire threat analysis (BFTA) is an assessment of the comparative risk of damage resulting from bushfires in Western Australia …

Agricultural burning is an important land use practice in the central U.S. but has received little attention in the literature, whereas …

The Indonesian islands of Sumatera and Kalimantan (the Indonesian part of the island of Borneo) are a center of significant and rapid …

A desirable feature of a global sampling design for estimating forest cover change based on satellite imagery is the ability to adapt …

Monitoring loss of humid tropical forests via remotely sensed imagery is critical for a number of environmental monitoring objectives, …

Coastal wetland vegetation along the Great Lakes differs strongly with latitude, but most studies of Great Lakes wetland condition have attempted to exclude the effect of latitude to discern anthropogenic effects on condition. This approach provides a means to identify wetlands worthy of preservation, to establish vegetation targets for wetland restoration, and to forecast changes in floristic quality associated with future climate change.

The invasion and expansion of the non-native Phragmites australis in Great Lakes coastal wetlands is of increasing concern. Monitoring coastal wetlands where water level has dropped and controlling Phragmites at early stages of invasion are essential for maintaining healthy Great Lakes coastal wetlands of high species diversity and wildlife habitat. This becomes important as water levels in the Great Lakes have reached extreme lows and are expected to decline with future climate change.

The wetland complex is the functional ecological unit of the prairie pothole region (PPR) of central North America. Maintaining ecosystem goods and services at current levels in a warmer climate will be a major challenge for the conservation community.

Assessment of vegetation is an important part of evaluating wetland condition, but it is complicated by the variety of plant communities that are naturally present in freshwater wetlands. Our findings provide a means of using vegetation to evaluate a range of wetland condition across a broad and diverse geographic region.

Three sampling designs —simple random, stratified random, and systematic sampling —are compared onthe basis of precision of estimated loss of intact humid tropical forest area in the Brazilian Legal Amazon from 2000 to 2005. The results of this case study demonstrate the utility of a stratified design based on MODIS-derived deforestationdata to improve precision of the estimated loss of intact forest area as estimated from sampling Landsat imagery.

Great Lakes coastal wetlands are subject to water level fluctuations that promote the maintenance of coastal wetlands. Point au Sauble, …

QuickBird multispectral satellite images taken in September 2002 (peak biomass) and April2003 (pre-growing season) were used to map emergent wetland vegetation communities, particularlyinvasive Phragmites australis and Typha spp., within a diked wetland at the western end of Lake Erie. Multiseason QuickBird imagery is promising fordistinguishing certain wetland plant species, but should be used with caution in highly managed areaswhere vegetation changes may reflect human alterations rather than phenological change.

Plant taxa identified in 90 U.S. Great Lakes coastal emergent wetlands were evaluated as indicators of physical environment. A fuller understanding of how the physical environment influences plant species distribution will improve our ability to detect the response of wetland vegetation to anthropogenic activities.

Emergent plants can be suitable indicators of anthropogenic stress in coastal wetlands if their responses to natural environmental …

We present the distribution and aquatic habitat use of amphibian communities in two river basins of Transylvania (Romania) on a medium …