Browsing by Author "Beale, John"

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    A Method to Assess the Performance of SAR-derived Surface Soil Moisture Products
    (Cranfield University, 2021-04-13 09:13) Beale, John; Waine, Toby; Corstanje, Ronald; Evans, Jonathan
    A Method to Assess the Performance of SAR-derived Surface Soil Moisture Products John Beale, Toby Waine, Jonathan Evans, Ronald Corstanje This study brought together existing research data obtained from a number of different sources, some of which were upon request and subject to licence restrictions. Full details of how these data may be obtained are in this document
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    Continuous isoprene measurements in a UK temperate forest for a whole growing season: effects of drought stress during the 2018 heatwave
    (American Geophysical Union (AGU), 2020-07-08) Ferracci, Valerio; Bolas, Conor G.; Freshwater, Ray A.; Staniaszek, Zosia; King, Thomas; Jaars, Kerneels; Otu‐Larbi, Frederick; Beale, John; Malhi, Yadvinder; Waine, Toby William; Jones, Roderic L.; Ashworth, Kirsti; Harris, Neil
    Isoprene concentrations were measured at four heights below, within and above the forest canopy in Wytham Woods (UK) throughout the summer of 2018 using custom-built gas chromatographs (the iDirac). These observations were complemented with selected ancillary variables, including air temperature, photosynthetically active radiation (PAR), occasional leaf gas exchange measurements and satellite retrievals of normalized difference vegetation and water indices (NDVI and NDWI). The campaign overlapped with a long and uninterrupted heatwave accompanied by moderate drought. Peak isoprene concentrations during the heatwave-drought were up to a factor of 4 higher than those before or after. Higher temperatures during the heatwave could not account for all the observed isoprene; the enhanced abundances correlated with drought stress. Leaf-level emissions confirmed this and also included compounds associated with ecosystem stress. This work highlights that a more in-depth understanding of the effects of drought stress is required to better characterize isoprene emissions.
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    Improved soil moisture estimation with Sentinel-1 for arable land at the field scale
    (EGU: European Geophysical Union, 2021-04-30) Beale, John; Waine, Toby; Corstanje, Ron; Evans, Jonathan
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    The land-river interface: a conceptual framework of environmental process interactions to support sustainable development
    (Springer, 2022-05-13) Grabowski, Robert C.; Vercruysse, Kim; Holman, Ian P.; Azhoni, Adani; Bala, Brij; Shankar, Vijay; Beale, John; Mukate, Shrikant; Poddar, Arunava; Peng, Jian; Meersmans, Jeroen
    Rivers and their surrounding lands are focal points of human development in the landscape. However, activities associated with development can greatly affect river processes, causing significant and often unintended environmental and human impacts. Despite the profound and varied environmental impacts that development-related alterations cause through hydrological, geomorphic, and ecological processes, they are not widely acknowledged outside of river management and affect resource availability and hazard exposure to people. In this paper, we propose a novel, interdisciplinary conceptual framework of river–land process interactions to support sustainable management and development. We introduce the term ‘land–river interface’ (LRI) to describe areas of the landscape in which river processes affect land, vegetation, and/or fauna, including humans, directly or indirectly. The multiple links between LRI processes and factors at the river basin, valley, and river channel (i.e. reach) scale are synthesized and a conceptual zonation of the LRI based on the process is proposed to serve as a framework to understand the impacts of human activity. Three examples of development-related activities (urbanization, dams and aggregate mining) illustrate how alteration to the form and functioning of river basins, valleys, and channels cause a range of impacts to be propagated throughout the landscape, often spatially or temporally distant from the activity. The diversity and severity of these impacts on the environment and people underscore the need to incorporate river processes, as represented in the LRI concept, into broader environmental management to better anticipate and mitigate negative impacts and maximize positive outcomes to deliver the benefits of sustainable development across society.
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    A method to assess the performance of SAR-derived surface soil moisture products
    (IEEE, 2021-04-06) Beale, John; Waine, Toby
    Synthetic aperture radar (SAR) is a remote sensing technique for mapping of soil moisture with high spatial resolution. C -band SAR can resolve features at field scale, or better, but responds to moisture only within the top 1 to 2 cm of the soil. When validating SAR-derived soil moisture products against standard in situ measurements at 5 to 10 cm depth, the greater moisture variability at the soil surface may be inaccurately categorized as measurement error. An alternative method was developed where the C -band SAR product is validated against soil moisture simulated at 2 cm depth by the HYDRUS-1D model. This reproduces soil moisture depth profiles from daily meteorological observations, leaf area index, and soil hydraulic parameters. The model was fitted at 13 COSMOS-UK sites so that the model output at 10 cm depth closely reproduced the cosmic ray neutron sensor data. At ten of the sites studied, there was an improvement of up to 8% in root-mean-squared difference by validating the Copernicus surface soil moisture (SSM) product at 2 cm compared to 10 cm. This suggests that Copernicus SSM and other C -band SAR surface soil moisture algorithms may be more accurate than have hitherto been acknowledged.
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    Vegetation cover dynamics along two Himalayan rivers: drivers and implications of change
    (Elsevier, 2022-08-18) Beale, John; Grabowski, Robert C.; Lokidor, Pauline Long'or; Vercruysse, Kim; Simms, Daniel M.
    Rivers are dynamic landscape features that change in response to natural and anthropogenic factors through hydrological, geomorphic and ecological processes. The severity and magnitude of human impacts on river system and riparian vegetation has dramatically increased over the last century with the proliferation of valley-spanning dams, intensification of agriculture, urbanization, and more widespread channel engineering. This study aims to determine how changes in geomorphic form and dynamics caused by these human alterations relate to changes in channels and riparian vegetation in the lower Beas and Sutlej Rivers. These rivers are tributaries of the Indus that drain the Western Himalayas but differ in the type and magnitude of geomorphic change in recent decades. Winter season vegetation was analysed over 30 years, revealing increasing trends in vegetated land cover in the valleys of both rivers, consistent with large-scale drivers of change. Greater trends within the active channels indicate upstream drivers are influencing river flow and geomorphology, vegetation growth and human exploitation. The spatial patterns of vegetation change differ between the rivers, emphasizing how upstream human activities (dams and abstraction) control geomorphic and vegetation community response within the landscape context of the river. The increasing area of vegetated land is reinforcing the local evolutionary trajectory of the river planform from wide-braided wandering to single thread meandering. Narrowing of the active channels is altering the balance of resource provision and risk exposure to people. New areas being exploited for agriculture are exposed to greater risk from river erosion, inundation, and sediment deposition. Moreover, the change from braided to meandering planform has concentrated erosion on riverbanks, placing communities and infrastructure at risk. By quantifying and evaluating the spatial variations in vegetation cover around these rivers, we can better understand the interaction of vegetation and geomorphology alongside the impacts of human activity and climate change in these, and many similar, large systems, which can inform sustainable development.