Joseph P. McFadden's research while affiliated with University of California, Santa Barbara and other places

Publications (74)

Article
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On 9 January 2018, Carpinteria Salt Marsh Reserve received a large quantity of sediment following debris flows in Montecito, California. Because disturbances potentially impact the ecosystem services and functions that wetlands provide, an understanding of how the ecosystem responded to the debris flows is important for the management of salt marsh...
Preprint
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Twenty urban neighbourhood-scale eddy covariance flux tower datasets have been harmonized and quality controlled, producing a 50 site-year collection with broad diversity in climate and urban surface characteristics. Observations are gap-filled and prepended with 10 years of reanalysis-derived local data to enable use as spin up and forcing for lan...
Article
Vegetation in urban areas can provide many ecosystem services, such as cooler temperatures. In water-limited climates, maintaining benefits from vegetation during droughts requires significant water inputs and can be challenging due to the uneven effects of drought on vegetation. Here, we tracked changes in vegetation cover in Los Angeles, Californ...
Article
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To compare the impact of surface-atmosphere exchanges from rural and urban areas, fully vegetated areas (e.g. deciduous trees, evergreen trees and grass) commonly found adjacent to cities need to be modelled. Here we provide a general workflow to derive parameters for SUEWS (Surface Urban Energy and Water Balance Scheme), including those associated...
Article
The effects of drought can manifest in vegetation across an array of physiological responses and time scales. In metropolitan areas, vegetation provides shading and cooling during hot and dry conditions, but these benefits can be reduced with drought. While many studies have evaluated interannual vegetation drought responses, these responses to dro...
Article
Urban vegetation mitigates elevated temperatures in cities. Drought presents an important challenge to urban heat mitigation as prolonged dry periods cause reduced evapotranspiration and losses of green vegetation cover. To measure drought impacts on the urban environment and climate, we used visible short-wave infrared satellite imagery acquired t...
Article
Local and regional urban surface heterogeneity produces diverse urban climates, significantly impacting water use, energy consumption, and human health. This study examines urban energy flux variability across landcover and climate gradients for 2123 km² of urbanized Los Angeles County, USA, by using high resolution remote sensing combined with spa...
Preprint
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This paper extends the applicability of the SUEWS (Surface [Urban] Energy and Water Balance Scheme) to extensive pervious areas (deciduous trees, evergreen trees, grass, croplands, soil and water) outside cities. It can be used either offline or online (i.e., coupled to weather/climate models). The required parameters to simulate the turbulent late...
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Understanding atmospheric water vapor patterns can inform regional understanding of water use, climate patterns and hydrologic processes. This research uses Airborne Visible Infrared Imaging Spectrometer (AVIRIS) reflectance and water vapor imagery to investigate spatial patterns of water vapor in California’s Central Valley on a June date in 2013,...
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There is a growing need to simulate the effect of urban planning on both local climate and greenhouse gas emissions. Here, a new urban surface carbon dioxide (CO2) flux module for the Surface Urban Energy and Water Balance Scheme is described and evaluated using eddy covariance observations at two sites in Helsinki in 2012. The spatial variability...
Article
Remote sensing can inform agricultural knowledge of crop water use through observation of land surface temperature, which can act as an indicator of plant function and health. This study uses remotely sensed data to quantify thermal variability within fruit and nut orchards during an intense drought period in California's Central Valley (2013–2015)...
Article
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Urban trees provide valuable ecosystem services but are at the same time under continuous pressure due to unfavorable site conditions. In order to better protect and manage our natural capital, urban green managers require frequent and detailed information on tree health at the city wide scale. In this paper we developed a workflow to monitor tree...
Article
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Although gross primary productivity (GPP) is estimated with remote sensing over large regions of Earth, urban areas are usually excluded due to the lack of light use efficiency (LUE) parameters for urban vegetation and the spatial heterogeneity of urban land cover. Here, we estimated midsummer GPP, both within and among vegetation and land-use type...
Article
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In California, predicted climate warming increases the likelihood of extreme droughts. As irrigated agriculture accounts for 80% of the state’s managed water supply, the response of the agricultural sector will play a large role in future drought impacts. This study examined one drought adaptation strategy, changes in planting decisions, using Airb...
Article
In cities, vegetation temperature is important for quantifying water use, microclimates, and water and energy fluxes, as demonstrated by urban climate models and in situ studies. Remote sensing is capable of observing land surface temperatures (LST) across a city; however, its ability to quantify vegetation canopy temperatures is limited because of...
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The vernal equinox total solar eclipse of 20 March 2015 produced a maximum occultation of 65.8 to 70.1 % over Switzerland during the morning hours (09:22 to 11:48 CET). Skies were generally clear over the Swiss Alps due to a persistent high-pressure band between the UK and Russia associated with a rather weak pressure gradient over the continent. T...
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While approximately 338 million people in the Northern hemisphere live in regions that are regularly snow covered in winter, there is little hydro-climatologic knowledge in the cities impacted by snow. Using observations and modelling we have evaluated the energy and water exchanges of four cities that are exposed to wintertime snow. We show that t...
Article
Eddy covariance flux measurements are increasingly used to quantify the net carbon dioxide exchange (FC) in urban areas. FC represents the sum of anthropogenic emissions, biogenic carbon release from plant and soil respiration, and carbon uptake by plant photosynthesis. When FC is measured in natural ecosystems, partitioning into respiration and ph...
Article
Future space-borne imaging spectrometers could enable global comparative analyses of urban composition. In particular, the high spectral resolution of imaging spectrometry could improve the discrimination of materials that have similar spectral signatures but are functionally dissimilar, such as turfgrass and trees. However, the amount of reflected...
Article
AimWe propose and test a climate tolerance and trait choice hypothesis of urban macroecological variation in which strong filtering associated with low winter temperatures restricts urban biodiversity while weak filtering associated with warmer temperatures and irrigation allows dispersal of species from a global source pool, thereby increasing urb...
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This study examines the distributional equity of urban tree canopy (UTC) cover for Baltimore, MD, Los Angeles, CA, New York, NY, Philadelphia, PA, Raleigh, NC, Sacramento, CA, and Washington, D.C. using high spatial resolution land cover data and census data. Data are analyzed at the Census Block Group levels using Spearman's correlation, ordinary...
Article
A small, but growing, number of flux towers in urban environments measure surface–atmospheric exchanges of carbon dioxide by the eddy covariance method. As in all eddy covariance studies, obtaining annual sums of urban CO2 exchange requires imputation of data gaps due to low turbulence and non-stationary conditions, adverse weather, and instrument...
Conference Paper
Background/Question/Methods Cities contain a unique composition of managed and unmanaged plants, many of which are non-native to the region. This proliferation of exotic species has been documented to have a homogenizing effect on the biodiversity of urban systems. Mechanisms behind similar tree compositions across cities are still under debate....
Conference Paper
Background/Question/Methods Excess nutrient loading to the environment can degrade ecosystem functions and impact human health, while at the same time depleting nonrenewable nutrient sources by moving them into nonrecoverable pools. In this study, part of the Twin Cities Household Ecosystem Project (TCHEP), we examine carbon (C), nitrogen (N), and...
Article
In a suburban neighborhood of Minneapolis-Saint Paul, Minnesota, USA, we simultaneously measured net CO2 exchange of trees using sap flow and leaf gas exchange measurements, net CO2exchange of a turfgrass lawn using eddy covariance from a portable tower, and total surface-atmosphere CO2 fluxes (FC) using an eddy covariance system on a tall tower. T...
Conference Paper
Background/Question/Methods The structure and composition of ecosystems influences regional and global climate through multiple pathways. Changes in species composition expected with climate change over the next several centuries may accelerate or moderate temperature increases by influencing surface energy exchange, the buildup of greenhouse gas...
Article
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Urban areas are among the most heavily managed landscapes in the world, yet they harbor a remarkable richness of species. Private yards are common habitats in urban areas and are places where cultivated species manage to escape cultivation and become part of the spontaneous species pool. Yards are novel ecosystems where community assembly is driven...
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Trees provide important ecological services in cities, yet the vulnerability of the urban forest to massive tree losses from pest outbreaks could threaten those services, with unknown environmental consequences. The outbreak of emerald ash borer is an imminent threat to the ash population in North America. In the Minneapolis–Saint Paul, Minnesota,...
Article
The occurrence of two major Amazonian droughts in 2005 and 2010 underscores the need for improved understanding of how drought affects tropical forest. During both droughts, MODIS land surface temperature data detected anomalously high daytime and nighttime canopy temperatures throughout drought-affected regions. Daytime thermal anomalies explained...
Article
Developed land - cities, suburbs, and exurban settlements - is a significant and growing fraction of the land-use in many regions over which we hope to construct carbon budgets. While anthropogenic CO2 fluxes have been estimated using emissions inventories and atmospheric tracers, there is very little data on the net ecosystem CO2 exchange (NEE) of...
Conference Paper
In post-industrial cities large proportions of inputs of energy, carbon, and nutrients enter via households. To quantify these fluxes, we developed a hybrid survey approach to analyze fluxes through 1,800 household systems in the Twin Cities Household Ecosystem Project. Survey results show that the distributions of both total and component fluxes a...
Article
Full-text available
The occurrence of two major Amazonian droughts in 2005 and 2010 underscores the need for improved understanding of how drought affects tropical forest. During both droughts, MODIS land surface temperature data detected anomalously high daytime and nighttime canopy temperatures throughout drought-affected regions. Daytime thermal anomalies explained...
Conference Paper
Background/Question/Methods The Los Angeles water system is highly engineered, involving water sources that have been imported over hundreds of kilometers. However, hydrology and ecology are still closely linked in this ecosystem, as in most semi-arid urban ecosystems in which surface characteristics, vegetation, climate, and water flows are all h...
Article
Rapid worldwide urbanization calls for a better understanding of the biogeochemical cycling of those macroelements that have large environmental impacts in cities. This study, part of the Twin Cities Household Ecosystem Project, quantified fluxes of carbon (C), nitrogen (N), and phosphorus (P) at the scale of individual households in the Minneapoli...
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We assessed biogeochemical cycling of elements through residential household landscapes to evaluate the importance of annual to decadal household-level decisions for element fluxes that contribute to urban and regional pollution. We combined a mailed survey, vegetation measurements, and allometric and biogeochemical models to estimate fluxes and ac...
Article
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Urban water systems are highly engineered. However, hydrology and ecology are still closely linked in semi-arid urban ecosystems in which surface characteristics, vegetation, and water flows are all highly transformed. Although these systems are human-dominated, there are many uncertainties in the water budgets of semi-arid cities, because evapotra...
Article
Evapotranspiration is an important term of energy and water budgets in urban areas and is responsible for multiple ecosystem services provided by urban vegetation. The spatial heterogeneity of urban surface types with different seasonal water use patterns (e.g., trees and turfgrass lawns) complicates efforts to predict and manage urban evapotranspi...
Article
Tree transpiration provides a variety of ecosystem services in urban areas, including amelioration of urban heat island effects and storm water management. Tree species vary in the magnitude and seasonality of transpiration owing to differences in physiology, response to climate, and biophysical characteristics, thereby complicating efforts to mana...
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Urbanization is responsible for some of the fastest rates of land-use change around the world, with important consequences for local, regional, and global climate. Vegetation, which represents a significant proportion of many urban and suburban landscapes, can modify climate by altering local exchanges of heat, water vapor, and CO2. To determine ho...
Article
Turf-grass lawns are ubiquitous in the United States. However direct measurements of land–atmosphere fluxes using the eddy-covariance method above lawn ecosystems are challenging due to the typically small dimensions of lawns and the heterogeneity of land use in an urbanised landscape. Given their typically small patch sizes, there is the potential...
Article
Urban trees provide a variety of ecosystem services to urban and suburban areas, including carbon uptake, climate amelioration, energy reduction, and stormwater management. Tree transpiration, in particular, modifies urban water budgets by providing an alternative pathway for water after rain events. The relative importance of environmental and bio...
Article
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Previous measurements of urban energy balances generally have been limited to densely built, central city sites and older suburban locations with mature tree canopies that are higher than the height of the buildings. In contrast, few data are available for the extensive, open vegetated types typical of low-density residential areas that have been n...
Conference Paper
Background/Question/Methods Households often account for a major fraction of carbon (C), nitrogen (N), and phosphorus (P) fluxes through post-industrial cities. Because of this, we need to understand drivers of household biogeochemistry in order to fully conceptualize urban biogeochemical cycling, but the methodologies for this complex system are...
Conference Paper
Background/Question/Methods Urban trees provide a variety of ecosystem services to urban and suburban areas, including carbon uptake, climate amelioration, energy reduction, and stormwater management. Tree transpiration, in particular, modifies urban water budgets by providing an alternative pathway for water after rain events. The relative import...
Article
Urban areas are spatially complex landscapes composed of many different land cover types, including impervious surfaces, buildings, bare soil, trees and lawns. This heterogeneity presents a challenge for measuring, modeling and scaling up the ecological effects of urbanization on land-atmosphere exchanges of energy, water, and CO2. Vegetation, whic...
Article
Half the world's population currently lives in urbanized areas, a proportion expected to increase to 60% by 2030. The clearing of agricultural and natural ecosystems for urban and suburban development is consequently one of the fastest rates of land use change around the world. Although developed land areas represent major sources of CO2 and alter...
Article
The rate at which wildlands and croplands are being developed for human settlement in the Unites States currently exceeds population growth by a factor of two to four. In the mid-continental U.S., the region of the first NACP intensive experiment, the area occupied by traditionally defined urban areas (cities and towns) is 4%, whereas the area cove...
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Important land surface characteristics affect the way in which water is transferred to the atmosphere, processed in the atmosphere, and eventually returned to the surface. In turn, the amount of water in the atmosphere and returning to Earth affects many of the key properties of the land surface. It is hypothesized that feedbacks between the terres...
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A major challenge in predicting Earth's future climate state is to understand feedbacks that alter greenhouse-gas forcing. Here we synthesize field data from arctic Alaska, showing that terrestrial changes in summer albedo contribute substantially to recent high-latitude warming trends. Pronounced terrestrial summer warming in arctic Alaska correla...
Article
Roughly 70% of the tundra north of the Brooks Range, Alaska, can be classified as moist nonacidic (39%) and moist acidic tundra (31%). We investigated the differences in energy partitioning and carbon balance among these two important landscape types. Despite structural differences in plant growth forms, moss cover, and soil pH, the sensible and la...
Article
Water vapor and CO2 exchanges were measured by the eddy covariance method in 24 ecosystems along a transect from the Arctic coast to the latitudinal tree line in northern Alaska during three growing seasons. Variations in net ecosystem exchange across the region were controlled by differences in the net uptake of CO2 due to photo- synthesis, rather...
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this paper, we report measurements of two lakes in which water-atmosphere fluxes of CO 2 , water vapor, and energy were measured during periods with convective mixing of the epilimnion: (1) during a cross-calibration experiment over Toolik Lake (Alaska), where floating chamber and EC flux measurements were simultaneously performed over four days in...
Article
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CO2 exchange between lake water and the atmosphere was investigated at Toolik Lake (Alaska) and Soppensee (Switzerland) employing the eddy covariance (EC) method. The results obtained from three field campaigns at the two sites indicate the importance of convection in the lake in driving gas flux across the water-air interface. Measurements were pe...
Article
Full-text available
CO2 exchange between lake water and the atmosphere was investigated at Toolik Lake (Alaska) and Soppensee (Switzerland) employing the eddy covariance (EC) method. The results obtained from three field campaigns at the two sites indicate the importance of convection in the lake in driving gas flux across the water-air interface. Measurements were pe...
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¶An overview of the Regional Atmospheric Modeling System (RAMS) is presented. We focus on new developments in the RAMS physics and computational algorithms since 1992. We also summarize some of the recent applications of RAMS that includes synoptic-scale weather systems and climate studies, to small-scale research using RAMS configured as a large e...
Article
In arctic tundra, shrubs can significantly modify the distribution and physical characteristics of snow, influencing the exchanges of energy and moisture between terrestrial ecosystems and the atmosphere from winter into the growing season. These interactions were studied using a spatially distributed, physically based modelling system that represe...
Article
The arctic region provides a unique opportunity for modeling land-atmosphere interactions because its surface is characterized by a mosaic of a small number of vegetation types. Recent micrometeorological campaigns have documented spatial patterns and biogeophysical controls of land-atmosphere fluxes at numerous individual sites. However, eddy flux...
Article
In the Arctic, where wind transport of snow is common, the depth and insulative properties of the snow cover can be determined as much by the wind as by spatial variations in precipitation. Where shrubs are more abundant and larger, greater amounts of drifting snow are trapped and suffer less loss due to sublimation. The snow in shrub patches is bo...
Article
Assessments of carbon (C) fluxes in the Arctic require detailed data on both how and why these fluxes vary across the landscape. Such assessments are complicated because tundra vegetation has diverse structure and function at both local and regional scales. To investigate this diversity, the Arctic Flux Study has used the eddy covariance technique...
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This paper summarizes and analyses available data on the surface energy balance of Arctic tundra and boreal forest. The complex interactions between ecosystems and their surface energy balance are also examined, including climatically induced shifts in ecosystem type that might amplify or reduce the effects of potential climatic change.High latitud...