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Thomas Gumbricht

Thomas Gumbricht
Karttur AB · Selfemployed

PhD

About

43
Publications
8,767
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1,862
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Introduction
I am a scientist focusing on natural resources modeling, mapping, monitoring and management using spatial data. At present I develop tools for mapping and monitoring of global wetlands and peatlands. I have deep knowledge in agroforestry, forestry, hydrology, wetlands, systems ecology, spatial data processing, remote sensing, geoinformatics and web map building. I have worked 15 years at different universities and 15 years for UN-related research organizations in Africa and Asia.

Publications

Publications (43)
Preprint
Full-text available
The Arctic is rapidly changing. Outside the Arctic, large-sample catchment databases have transformed catchment science from focusing on local case studies to more systematic studies of watershed functioning. Here we present an integrated pan-ARctic CAtchments summary DatabasE (ARCADE) of >40,000 catchments that drain into the Arctic Ocean and rang...
Article
Full-text available
Dynamics of global wetlands are closely linked to biodiversity conservation, hydrology, and greenhouse gas emissions. However, long-term time series of global wetland products are still lacking. Using a diagnostic model based on the TOPography-based hydrological MODEL (TOPMODEL), this study produced an ensemble of 28 gridded maps of monthly global/...
Article
Full-text available
Seasonal and interannual variations in global wetland area are a strong driver of fluctuations in global methane (CH4) emissions. Current maps of global wetland extent vary in their wetland definition, causing substantial disagreement between and large uncertainty in estimates of wetland methane emissions. To reconcile these differences for large-s...
Preprint
Full-text available
Seasonal and interannual variations in global wetland area is a strong driver of fluctuations in global methane (CH4) emissions. Current maps of global wetland extent vary with wetland definition, causing substantial disagreement and large uncertainty in estimates of wetland methane emissions. To reconcile these differences for large-scale wetland...
Article
Full-text available
A soil wetness index for optical satellite images, the Transformed Wetness Index (TWI) is defined and evaluated against ground sampled soil moisture. Conceptually, TWI is formulated as a non-linear normalized difference index from orthogonalized vectors representing soil and water conditions, with the vegetation signal removed. Compared to 745 grou...
Article
Full-text available
Wetlands are important providers of ecosystem services and key regulators of climate change. They positively contribute to global warming through their greenhouse gas emissions, and negatively through the accumulation of organic material in histosols, particularly in peatlands. Our understanding of wetlands' services is currently constrained by lim...
Chapter
The annual cyclic phenomena of soil surface wetness influences for instance vegetation growth, drought, flooding, and soil properties. This study presents an attempt to define metrics relevant for capturing the soil moisture dynamics from an annual series of wetness estimates derived from global Moderate-resolution imaging spectroradiometer (MODIS)...
Article
Full-text available
There is a need for up-to-date assessments and maps of soil properties and land health at scales relevant for decision-making and management, including for properties that are dynamic and hence change in response to management. Also, there is a need for approaches to soil mapping that capture the ever increasing effects that humans are having on th...
Article
Full-text available
The Okavango Delta is dominated by annual flood events from the Okavango River. During such events the inundated area increases from about 5000 km2 to 6000–12,000 km2. Several models of a conceptual character were developed previously to represent hydrological processes in that system. Although essentially successful in their applications, the mode...
Article
Full-text available
In the endorheic Okavango River system in southern Africa a balance between human and environmental water demands has to be achieved. The runoff generated in the humid tropical highlands of Angola flows through arid Namibia and Botswana before forming a large inland delta and eventually being consumed by evapotranspiration. With an approximate size...
Article
The Okavango inland Delta in Botswana is characterized by a high spatial and temporal variation in vegetation patches and flooding. Predicting the effects of escalating development projects in this pristine wildlife area is hampered by a lack of accurate maps. Efforts using traditional statistical methods have been futile. The processes forming thi...
Article
Spatially distributed modelling is dependent on segmentation of the underlying geographic data and the model output could be improved if relevant compartments are found and used. Herein, we present a method for identifying subbasins in complex topographic waterscapes. The method first finds local troughs and then expands them over a friction surfac...
Article
The surface of the 40 000 km2 Okavango alluvial fan is remarkably smooth, and almost everywhere lies within two to three metres of a perfectly smooth theoretical surface. Deviations from this perfect surface give rise to islands in the Okavango wetlands. This micro-topography was mapped by assigning empirical elevations to remotely sensed vegetatio...
Article
Many safari lodges in the Okavango Delta obtain their water supply from boreholes in near-surface aquifers while disposing of their wastewater via soak-aways, creating a potential risk of contamination of their water supply. Most islands in the Delta contain sites where the groundwater has become salinised as aresult of transpiration by island vege...
Article
The pristine Okavango Delta wetland of northern Botswana is potentially under threat due to water abstraction from its tributaries. We have developed a statistical model which makes it possible to predict the extent of wetland loss which will arise from water abstraction. The model also permits prediction of the maximum area of flooding, and its sp...
Article
The Okavango wetland in northern Botswana is one of the world's largest inland deltas. The delta is a dynamic environment with shifting channel routes, causing growth and decay of flanking wetlands, and giving birth to islands. Primary island nuclei are formed by fluvial processes and bioengineering, and subsequently grow into secondary larger isla...
Article
The inundated area of the Okavango Delta changes annually and interannually. The variability relates to regional precipitation over the catchment area in the Angolan highlands, and to local rainfall. The patterns of the wetland were captured using more than 3000 satellite images for the period 1972 to 2000, near daily NOAA AVHRR data for 1985-2000,...
Article
Islands in the Okavango Delta in Northern Botswana have a large influence on water flow, evapotranspiration and salinity balance. In this study island orientation and the occurrence of salt crusts on islands was explored in relation to both the regional Delta azimuth and proximity to channels. Islands, particularly those of larger size, are oriente...
Article
Full-text available
The Okavango Delta in Botswana is one of the world's most fascinating wetland systems. A hydrological model of the Delta is presented, which is based on a finite difference formulation of the relevant flow processes (surface water and groundwater). Spatially distributed input data include rainfall, évapotranspiration and microtopography. The model...
Article
As a consequence of the constantly shifting water distribution in the Okavango Delta, Botswana, peat accumulated in former wetlands adjacent to receding channels is consumed by fire in successive layers as the peat desiccates. Burning peat has been recorded around the dying Thaoge channel since the mid-19th century. In this study, five different re...
Chapter
Full-text available
The Okavango “Delta” is a large (25,000 km²), low-gradient (1:3400) alluvial fan which has developed in a depression between two basement arch-horst systems which mark the tips of incipient rifts. Base flow in the Okavango River sustains about 4000 km² of permanent wetland in the Delta, while the seasonal flood can expand the area of inundation to...
Article
A topographic map of the Okavango Delta and environs has been constructed using a combination of elevation data including trigonometric beacons and spot heights from the government of Botswana, surveys of the navigable channels, U. S. Department of Defense data and measurements made during a geophysical survey of the region. The topography provides...
Article
A topographic map of the Okavango Delta and environs has been constructed using a combination of elevation data including trigonometric beacons and spot heights from the government of Botswana, surveys of the navigable channels, U. S. Department of Defense data and measurements made during a geophysical survey of the region. The topography provides...
Article
Full-text available
The article presents the application of remote sensing for capturing hydrological and ecosystem patterns and processes (geophysiology) of the Okavango inland delta in Botswana. The whole catchment is portrayed from NOAA-AVHRR images at 2 to 8 km resolution, the physiographic regions of the Delta, the annual flooding and the vegetation cycle are ana...
Article
Geographical Information Systems provide a powerful tool for creating threedimensional (3D) datasets for sophisticated hydrogeological models. The article describes a GIS with an expert system interface developed for generating 3D hydrogeological frameworks. The system integrates 2D images of elevation and geology and vertical profile data. Applica...
Article
Land-surface modelling is traditionally based on reductionistic cause-effect models developed for the temperate region. Sustainable management of vulnerable and extreme regions demands a new holistic approach relying on first principles and integration of processes and patterns. In this article remotely sensed data and GIS are combined for creating...
Article
Knowledge based methods using Geographic Information System and Remote Sensing for land cover classification and future land allocation in Cyprus are presented. Land cover was categorized combining statistical classification and expert rules, using multi-temporal Landsat TM and MSS data, and digitized maps of elevation and geology. Land needed for...
Article
The multitude of environmental problems in a world of dynamic and unpredictable natural systems call for new methods that make use of recent development in the digital integration of human reasoning, data and dynamic models. A reported course in Natural Resources Management is based on holistic perception, systems dynamics and cybernetics, and uses...
Article
A hydrological model that attempts to incorporate the important distributed and dynamic effects of vegetation and surface topology is reported. Regional calibration is done based either on field conditions or optimization. The model is locally parameterized by GIS and by remotely sensed derived synoptic parameters of the landscape structure. This i...
Article
A recent development for the control of eutrophication is the application of ecological engineering, involving designed wetlands for water treatment. The most undeveloped concept for designed wetlands is the use of submersed macrophytes. Apart from nutrient uptake, the macrophytes play a crucial role by creating a favourable environment for a varie...
Article
The natural capacity of submersed plants to reduce the phosphorus and nitrogen content of polluted waters was investigated in a full-scale experiment with Elodea canadensis and Cladophora glomerata, grown in eutrophied stream water in 16 parallel canals in Southern Sweden. Between September 1988 and June 1991 the weekly mean reduction was 32% of ni...
Article
Between September 1988 and June 1991 a full-scale experiment with a 1100 m2 root-zone bed treating secondary wastewater was conducted in southern Sweden. The species used were Phragmites australis and Typha latifolia. The average hydraulic load in the studied root-zone was 16 cm day−1 per surface unit. Loads of nitrogen, phosphorus and BOD were 1.7...
Article
Modeling processes in GIS is both a step forwards and a step backwards. The article analyses some of the shortcomings in GIS modeling using the game of chess as an analogue for spatial processes. A research agenda for improved dynamic modeling in GIS is concluded.

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