Glacier motion estimation using SAR offset-tracking procedures

Two image-to-image patch offset techniques for estimating feature motion between satellite synthetic aperture radar (SAR) images are discussed. Intensity tracking, based on patch intensity cross-correlation optimization, and coherence tracking, based on patch coherence optimization, are used to estimate the movement of glacier surfaces between two SAR images in both slant-range and azimuth direction. The accuracy and application range of the two methods are examined in the case of the surge of Monacobreen in Northern Svalbard between 1992 and 1996. Offset-tracking procedures of SAR images are an alternative to differential SAR interferometry for the estimation of glacier motion when differential SAR interferometry is limited by loss of coherence, i.e., in the case of rapid and incoherent flow and of large acquisition time intervals between the two SAR images. In addition, an offset-tracking procedure in the azimuth direction may be combined with differential SAR interferometry in the slant-range direction in order to retrieve a two-dimensional displacement map when SAR data of only one orbit configuration are available

Gender inequalities in college major choices. The role of explicit and implicit stereotypes

College major choices are highly segmented by gender and generate persistent inequalities in the labour market at the disadvantage of women. The literature has underlined the role of gender stereotypes on college major choices and the costs both at individual and society level of the resulting mismatch of talents and wrong fields of education choices. Determinants of college major choices from a gender perspective are at the core of this paper which has also a special focus on the impact of gender stereotypes (implicit and explicit) and on the choice of economics as a college major. Microdata are generated by a field experiment involving different high schools in the last year of attendance when students are close to the college major choice. The schools are located in two Northern districts of Italy a country characterized by a very high gender gap in the labour market at the disadvantage of women. Activities include role models, board game addressing gender stereotypes in professional choices and documentaries highlighting the impact of gender stereotypes in the labour market. A questionnaire including Implicit association tests has been submitted to the sample exposed to the treatment and to the control groups to measure gender stereotypes, individual and household characteristics and the impact of the treatment on college major choices and their determinants. We find evidence of gender stereotypes among students, and – differentiating by gender –female students appear to have a higher level of implicit stereotypes than males. Female students participating in the experiment appear to increase their awareness concerning college major choice and their propensity for STEM and for finance over marketing within the economics courses whereas male students taking part in the activities appear to be more interested in pursuing higher education instead of looking for a job, are more uncertain about their future field of studies and increase their interest in humanities while showing a higher propensity for marketing instead than finance when compared to the male students’ control group

Regional and local land subsidence at the Venice coastland by TerraSAR-X PSI

Abstract. Land subsidence occurred at the Venice coastland over the 2008–2011 period has been investigated by Persistent Scatterer Interferometry (PSI) using a stack of 90 TerraSAR-X stripmap images with a 3 m resolution and a 11-day revisiting time. The regular X-band SAR acquisitions over more than three years coupled with the very-high image resolution has significantly improved the monitoring of ground displacements at regional and local scales, e.g., the entire lagoon, especially the historical palaces, the MoSE large structures under construction at the lagoon inlets to disconnect the lagoon from the Adriatic Sea during high tides, and single small structures scattered within the lagoon environments. Our results show that subsidence is characterized by a certain variability at the regional scale with superimposed important local displacements. The movements range from a gentle uplift to subsidence rates of up to 35 mm yr−1. For instance, settlements of 30–35 mm yr−1 have been detected at the three lagoon inlets in correspondence of the MoSE works, and local sinking bowls up to 10 mm yr−1 connected with the construction of new large buildings or restoration works have been measured in the Venice and Chioggia historical centers. Focusing on the city of Venice, the mean subsidence of 1.1 ± 1.0 mm yr−1 confirms the general stability of the historical center

Inventory and changes of rock glacier creep speeds in Ile Alatau and Kungöy Ala-Too, northern Tien Shan, since the 1950s

This research has been supported by the European Research Council (ICEMASS (grant no. 320816)) and the European Space Agency (grant nos. 40001161196/15/I-NB, 4000123681/18/I-NB, 4000109873/14/I-NB, 4000127593/19/I-NS, and 4000127656/19/NL/FF/gp). This work was funded by the ESA projects GlobPermafrost (40001161196/15/I-NB), Permafrost_CCI (4000123681/18/I-NB), and Glaciers_CCI (4000109873/14/I-NB, 4000127593/19/I-NS) and the ESA EarthExplorer10 Mission Advisory Group (4000127656/19/NL/FF/gp) as well as by the European Research Council under the European Union's Seventh Framework Programme (FP/2007-2013)/ERC grant agreement no. 320816.Spatio-temporal patterns related to the viscous creep in perennially frozen sediments of rock glaciers in cold mountains have rarely been studied outside the densely populated European Alps. This study investigates the spatial and temporal variability of rock glacier movement in the Ile Alatau and Kungöy Ala-Too mountain ranges, northern Tien Shan, a region with particularly large and fast rock glaciers. Over the study region of more than 3000 km2, an inventory of slope movements was constructed using a large number of radar interferograms and high-resolution optical imagery. The inventory includes more than 900 landforms, of which around 550 were interpreted as rock glaciers. Out of the active rock glaciers inventoried, 45 are characterized by a rate of motion exceeding 100 cm/a. From these fast rock glaciers we selected six (Gorodetzky, Morenny, Archaly, Ordzhonikidze, Karakoram, and Kugalan Tash) and studied them in more detail using offset tracking between repeat aerial images and historical and modern high-resolution optical satellite data. Two of these rock glaciers showed a steady increase in decadal surface velocities from the 1950s onwards, with speeds being roughly 2 to 4 times higher in recent years compared to the 1950s and 1960s. Three rock glaciers showed similar accelerations over the last 1 to 2 decades but also phases of increased speeds in the 1960s. This development indicates a possible significant increase in current sediment and ice fluxes through rock glaciers and implies that their material transport in the region might gain geomorphodynamic importance relative to material transport by glaciers, assuming the latter decreases together with the regional glacier shrinkage. The study demonstrates how air and satellite image archives are exploited to construct one of the longest decennial times series of rock glacier speeds currently available. Our results are in line with findings from Europe about rock glacier speeds increasing with atmospheric warming and underline local variability of such an overall response.Publisher PDFPeer reviewe