Reeves J.A.,Stanford University |
Knight R.,Stanford University |
Zebker H.A.,Stanford University |
Schreuder W.A.,Principia Mathematica |
And 2 more authors.
Water Resources Research | Year: 2011
In the San Luis Valley (SLV), Colorado legislation passed in 2004 requires that hydraulic head levels in the confined aquifer system stay within the range experienced in the years 1978-2000. While some measurements of hydraulic head exist, greater spatial and temporal sampling would be very valuable in understanding the behavior of the system. Interferometric synthetic aperture radar (InSAR) data provide fine spatial resolution measurements of Earth surface deformation, which can be related to hydraulic head change in the confined aquifer system. However, change in cm-scale crop structure with time leads to signal decorrelation, resulting in low quality data. Here we apply small baseline subset (SBAS) analysis to InSAR data collected from 1992 to 2001. We are able to show high levels of correlation, denoting high quality data, in areas between the center pivot irrigation circles, where the lack of water results in little surface vegetation. At three well locations we see a seasonal variation in the InSAR data that mimics the hydraulic head data. We use measured values of the elastic skeletal storage coefficient to estimate hydraulic head from the InSAR data. In general the magnitude of estimated and measured head agree to within the calculated error. However, the errors are unacceptably large due to both errors in the InSAR data and uncertainty in the measured value of the elastic skeletal storage coefficient. We conclude that InSAR is capturing the seasonal head variation, but that further research is required to obtain accurate hydraulic head estimates from the InSAR deformation measurements. Copyright 2011 by the American Geophysical Union.
Pedersen P.,Northern Research Institute Norut |
Pedersen P.,University of Tromsø
Norsk Geografisk Tidsskrift | Year: 2013
The coupling of different databases unlocks numerous possibilities for research on people's movements over time. The article shows how time series data can be converted to longitudinal statistics and how longitudinal data enable migration careers to be traced over several years. This is demonstrated by an analysis of the mobility patterns of persons in the age group 20-25 years in Northern Norway over a five-year period, with regard to the frequency and different types of migration, and the selection processes manifested in long-distance migration. Northern Norway is a peripheral region characterised by large distances between population centres, low population density, and an economy dependent upon raw materials. There are long distances to large labour market clusters both within the region and elsewhere in Norway. The analysis of the settlement patterns and migration careers indicates that the majority of the young adults, both male and female, did not migrate. Rather, the flow of migrants was created by a minority within the studied population. Further, female long-distance migrants to Southern Norway moved back to Northern Norway to a greater extent than men. The study nuances understanding of the migration patterns and demonstrates the value of applying longitudinal statistic in migration analysis. © 2013 © 2013 Norwegian Geographical Society.
Tommervik H.,Norwegian Institute for Nature Research |
Bjerke J.W.,Norwegian Institute for Nature Research |
Gaare E.,Norwegian Institute for Nature Research |
Johansen B.,Northern Research Institute Norut |
Thannheiser D.,University of Hamburg
Fungal Ecology | Year: 2012
During the last 25. yr, Sami reindeer husbandry in parts of Finnmarksvidda in the Norwegian Arctic has been in a critical state because of overexploitation of lichen-dominated tundra, which serves as winter forage. To better understand the ecosystem's capabilities for recovery we investigated vegetation cover changes over a 7-yr period, starting in 1998, at 52 sites dispersed over a large area at Finnmarksvidda. Two types of plots were established: one fenced from reindeer grazing and trampling and one open for reindeer. The investigations in 2005 showed that lichen cover had had a significant and rapid increase (up to 8.6-fold per year). The cover of vascular plants, mainly dwarf shrubs, also increased significantly, while barren areas and the cover of litter decreased significantly during the period. Mean relative growth rate of lichen biomass was 0.083 ± 0.011 per year in open plots, which is considered very rapid recovery compared to previous studies. Lichen recovery was significantly faster on leeward ridges than on exposed ridges, and fencing alone did not have any significant effects on lichen recovery, but in interaction with time, fencing contributed to increasing recovery rates. The lichen heath recovery was reciprocally correlated with reindeer density. In addition, lichen recovery was probably facilitated by recent climate changes, viz. shallower snow depths which made leeward tundra and forest floor vegetation accessible for reindeer, and increased summer precipitation rates which improved growth rates. The results from this study show that in a very short time there was a transition from an overexploited depauperate vegetation and barren ground state to a flourishing lichen-dominated vegetation state, suggesting that the injuries were repairable. The vegetation transitions which have taken place in the study area are considered to be reversible with fewer persistent effects. © 2011 Elsevier Ltd and The British Mycological Society.
Kumar V.,Indian Institute of Technology Bombay |
Venkataramana G.,Indian Institute of Technology Bombay |
Hogda K.A.,Northern Research Institute NORUT
International Journal of Applied Earth Observation and Geoinformation | Year: 2011
In this study ascending and descending passes interferometric synthetic aperture radar (InSAR) techniques are used for glacier surface velocity estimation in the Himalaya. Single-track interferometric measurements are sensitive to only a single component of the three dimensional (3-D) velocity vectors. European Remote Sensing satellites (ERS-1/2) tandem mission data in ascending and descending tracks provide an opportunity to resolve the three velocity components under the assumption that glacier flow is parallel to its surface. Using the surface slope as an essential input in this technique the velocity pattern of Siachen glacier in Himalaya has been modelled. Glaciers in the Himalayan region maintain excellent coherence of SAR return signals in one-day temporal difference. As a result we could obtain spatially continuous surface velocity field with a precision of fraction of radar wavelength. The results covering the main course of glacier are analysed in terms of spatial and temporal variations. A maximum velocity of 43 cm/day has been observed in the upper middle portion of the glacier. This technique has been found accurate for monitoring the flow rates in this region, suggesting that routine monitoring of diurnal movement Himalayan glaciers would be immensely useful in the present day context of climate change. © 2011 Elsevier B.V.
Lauknes T.R.,Northern Research Institute Norut
IEEE Geoscience and Remote Sensing Letters | Year: 2011
Interferometric synthetic aperture radar (SAR) (InSAR) phase is affected by atmospheric path delay. It is common to separate the path delay into one component related to turbulent mixing processes and one component related to tropospheric stratification. Tropospheric stratification introduces phase delays correlating with topography, limiting interpretation of InSAR data in areas with steep topography. Improved access to SAR time series has led to the development of several innovative multitemporal InSAR algorithms. Small baseline (SB) is one such time-series method, based on combining and inverting a set of unwrapped interferograms to estimate surface displacement. In this letter, we present a method for estimating and correcting the effects of tropospheric stratification observed in an SB stack of interferograms. We demonstrate the value of this approach using InSAR data from the Envisat spacecraft and compare the InSAR estimated delays with results from a Global Positioning System network. © 2011 IEEE.
Natalia K.,Northern Research Institute NORUT
Global health action | Year: 2011
Climate change and environmental pollution have become pressing concerns for the peoples in the Arctic region. Some researchers link climate change, transformations of living conditions and human health. A number of studies have also provided data on differentiating effects of climate change on women's and men's well-being and health. To show how the issues of climate and environment change, human health and gender are addressed in current research in the Arctic. The main purpose of this article is not to give a full review but to draw attention to the gaps in knowledge and challenges in the Arctic research trends on climate change, human health and gender. A broad literature search was undertaken using a variety of sources from natural, medical, social science and humanities. The focus was on the keywords. Despite the evidence provided by many researchers on differentiating effects of climate change on well-being and health of women and men, gender perspective remains of marginal interest in climate change, environmental and health studies. At the same time, social sciences and humanities, and gender studies in particular, show little interest towards climate change impacts on human health in the Arctic. As a result, we still observe the division of labour between disciplines, the disciplinary-bound pictures of human development in the Arctic and terminology confusion. Efforts to bring in a gender perspective in the Arctic research will be successful only when different disciplines would work together. Multidisciplinary research is a way to challenge academic/disciplinary homogeneity and their boundaries, to take advantage of the diversity of approaches and methods in production of new integrated knowledge. Cooperation and dialogue across disciplines will help to develop adequate indicators for monitoring human health and elaborating efficient policies and strategies to the benefit of both women and men in the Arctic. Global Health Action 2011. © 2011 Kukarenko Natalia.
Solbo S.,Northern Research Institute Norut |
Storvold R.,Northern Research Institute Norut
International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences - ISPRS Archives | Year: 2013
The remoteness of most Svalbard glaciers makes it difficult to perform regular in situ monitoring, especially in the melting season. Terminus areas (into the sea) and crevassed areas are in practice only accessible from the air. In this paper, first investigations on the feasibility of UAS based 3D measurements of glacier elevation is performed. The results show that UAS can be a valuable tool for glacier measurements in remote areas like Svalbard, where the only real alternative to measure glacier elevation in the ablation zone during the melt season is by manned aircraft. Imagery from repeated observations within a few days can be used to estimate dynamic mass loss rates when coupled to 3D modeling and feature tracking. Retrieval of these data is valuable, especially for glaciers terminating in the sea and surging glaciers.
Nilsen T.,Northern Research Institute NORUT
Energy Research and Social Science | Year: 2016
Recent explanations of regional path development tend to neglect public policy interventions into the analysis of new path creation in non-core regions. I argue that the evolutionary approach in economic geography effort in highlighting endogenous theories to explain industrial renewal in the periphery, should be more aware of theories of exogenous inflows from outside in order to explain innovation and growth in regions. I suggest that the concept of local content policies in the global petroleum industry is pivotal in understanding regions ability to break out of trajectories seen as path dependent in theories of regional development. Drawing on a combination of studies of three petroleum projects in the region of Finnmark and one in Nordland in Northern Norway, this paper explores recent local content initiatives, and evaluate their potential benefit for companies and regions. I argue that the role of policy actions should be a pivotal issue in explaining growth and innovation in peripheral areas, and that a combination of endogenous and exogenous factors gives a more balanced picture of the situation rather than leaning on endogenous factors alone. © 2016 Elsevier Ltd.
Aure M.,Northern Research Institute Norut
Norsk Geografisk Tidsskrift | Year: 2013
The relationship between migration, labour market access, and emotions has not been widely analysed despite ample evidence suggesting that difficulties with labour market entry evoke diverse feelings among migrants. The article analyses migrants' narratives of their feelings toward mobility and subsequent labour market participation based on research material relating to skilled migrants entering Norway. The author examines how understanding migrants' emotions associated with place-specific labour market entry, namely low self-esteem, shame, loss of individuality, and infantilisation, but also pleasure and content, can contribute to studies of the relationship between emotion and migration. Work-related and family-related mobility are often considered the least controversial forms of mobility. However, the article shows how they may have gendered emotional costs for the individuals involved. The author concludes that studies of migration and emotion should include these issues in order to tie migration, place, labour market participation, and gender together. © 2013 © 2013 Norwegian Geographical Society.
Nygaard V.,Northern Research Institute NORUT
Extractive Industries and Society | Year: 2015
The exploitation of mineral resources in the resource rich north is high up on the Norwegian political agenda. Northern parts are also the home of the Sami indigenous people using these territories for practicing traditional and modern livelihoods. This holds implications for future sustainable mining as well as indigenous wellbeing.This article addresses the role of the Sami indigenous people in the planning processes of new mining developments in the northernmost Norwegian region of Finnmark, and the degree to which different Sami stakeholders can influence these processes.Using planning documents and media articles collected during the planning processes of two new mining projects in the region, Nussir and Arctic Gold, the article examines the formal role of the Sami interests in mining licensing processes; the ways in which different Sami stakeholders take part in environmental impact assessment (EIA)-processes; and the extent to which Sami views are taken into account when it comes to important project decisions. The article operates from a local community perspective, applying the concept of social sustainability with theories of indigenous and local community participation in planning processes. © 2015 Elsevier Ltd.