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Cristina?Florina?Ro?caEmail author Gabriela?Victoria?Harpa Adina-Eliza?Croitoru Ioana?Herbel Alexandru?Mircea?Imbroane Doina?Cristina?Burada 《Theoretical and Applied Climatology》2017,130(3-4):775-790
Land surface temperature is one of the most important parameters related to global warming. It depends mainly on soil type, discontinuous vegetation cover, or lack of precipitation. The main purpose of this paper is to investigate the relationship between high LST, synoptic conditions and air masses trajectories, vegetation cover, and soil type in one of the driest region in Romania. In order to calculate the land surface temperature and normalized difference vegetation index, five satellite images of LANDSAT missions 5 and 7, covering a period of 26 years (1986–2011), were selected, all of them collected in the month of June. The areas with low vegetation density were derived from normalized difference vegetation index, while soil types have been extracted from Corine Land Cover database. HYSPLIT application was employed to identify the air masses origin based on their backward trajectories for each of the five study cases. Pearson, logarithmic, and quadratic correlations were used to detect the relationships between land surface temperature and observed ground temperatures, as well as between land surface temperature and normalized difference vegetation index. The most important findings are: strong correlation between land surface temperature derived from satellite images and maximum ground temperature recorded in a weather station located in the area, as well as between areas with land surface temperature equal to or higher than 40.0 °C and those with lack of vegetation; the sandy soils are the most prone to high land surface temperature and lack of vegetation, followed by the chernozems and brown soils; extremely severe drought events may occur in the region. 相似文献
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George Panteras Sarah Wise Xu Lu Arie Croitoru Andrew Crooks Anthony Stefanidis 《Transactions in GIS》2015,19(5):694-715
The analysis of social media content for the extraction of geospatial information and event‐related knowledge has recently received substantial attention. In this article we present an approach that leverages the complementary nature of social multimedia content by utilizing heterogeneous sources of social media feeds to assess the impact area of a natural disaster. More specifically, we introduce a novel social multimedia triangulation process that uses both Twitter and Flickr content in an integrated two‐step process: Twitter content is used to identify toponym references associated with a disaster; this information is then used to provide approximate orientation for the associated Flickr imagery, allowing us to delineate the impact area as the overlap of multiple view footprints. In this approach, we practically crowdsource approximate orientations from Twitter content and use this information to orient Flickr imagery accordingly and identify the impact area through viewshed analysis and viewpoint integration. This approach enables us to avoid computationally intensive image analysis tasks associated with traditional image orientation, while allowing us to triangulate numerous images by having them pointed towards the crowdsourced toponym location. The article presents our approach and demonstrates its performance using a real‐world wildfire event as a representative application case study. 相似文献
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Cheval Sorin Bulai Ana Croitoru Adina-Eliza Dorondel Ștefan Micu Dana Mihăilă Dumitru Sfîcă Lucian Tișcovschi Adrian 《Theoretical and Applied Climatology》2022,149(1-2):253-272
Theoretical and Applied Climatology - In the last decades, anthropogenic drivers have significantly influenced the natural climate variability of Earth’s atmosphere. Climate change has become... 相似文献
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Arie Croitoru Andrew Crooks Jacek Radzikowski Anthony Stefanidis 《International journal of geographical information science》2013,27(12):2483-2508
The remarkable success of online social media sites marks a shift in the way people connect and share information. Much of this information now contains some form of geographical content because of the proliferation of location-aware devices, thus fostering the emergence of geosocial media – a new type of user-generated geospatial information. Through geosocial media we are able, for the first time, to observe human activities in scales and resolutions that were so far unavailable. Furthermore, the wide spectrum of social media data and service types provides a multitude of perspectives on real-world activities and happenings, thus opening new frontiers in geosocial knowledge discovery. However, gleaning knowledge from geosocial media is a challenging task, as they tend to be unstructured and thematically diverse. To address these challenges, this article presents a system prototype for harvesting, processing, modeling, and integrating heterogeneous social media feeds towards the generation of geosocial knowledge. Our article addresses primarily two key components of this system prototype: a novel data model for heterogeneous social media feeds and a corresponding general system architecture. We present these key components and demonstrate their implementation in our system prototype, GeoSocial Gauge. 相似文献
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Relative orientation is one of the fundamental steps in forming a photogrammetric model. Whilst relative orientation is straightforward in most cases of aerial photogrammetry this may not be the case in close range photogrammetry where the nature of the photographs and the cameras being used often raise unfamiliar problems. This paper addresses the problem of performing relative orientation of non-metric photographs under unstable conditions where there are no ground control points and the ray intersection geometry is poor. The relative orientation problem is approached from several viewpoints, including a method that relies on little information about the exterior or relative orientation parameters. The solution is based on an iterative process, in which a set of three virtual control points (VCPs) is created, using photo coordinates and range ratios. The validity of the VCPs is checked during every iteration by an estimation of the coplanarity condition using two or more conjugate checkpoints. During the iteration a database is formed, which is then used to obtain a net of VCPs that fulfil the coplanarity condition for the checkpoints. The VCPs are then used to compute the "relative" exterior orientation by space resection. The proposed method was tested on both simulated and real photographs and was found to have some advantages over more commonly used techniques. 相似文献
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Adina-Eliza Croitoru Iulian-Horia Holobaca Catalin Lazar Florin Moldovan Alexandru Imbroane 《Climatic change》2012,111(2):393-410
Air temperature variability and trends in Romania were analysed using monthly, seasonal, and annual datasets. Temperature
data of winter wheat season were also analysed. The Mann-Kendall test, Sen’s slope estimate, the sequential version of the
Mann-Kendall test, the Pettitt test and spatial and temporal hierarchical cluster analyses were used. First, the datasets
were checked for changing points. The 106-year period was divided into two long periods of 100 years each to verify the importance
of a very short interval in changing of general trends; after that it was divided into three shorter periods of 35–36 years
each. The main conclusions are as follows: the 6 years making up the difference between the two long periods are very important
in the context of the recent global warming; the three shorter periods analysis indicate some fluctuations rather than continuous
warming. The latest short period is the most relevant for global warming. Spatial hierarchical cluster analysis indicated
the existence of two distinctive groups. One of them, which includes stations in the south-east part of the country, seems
to be influenced by the Black Sea surface temperature. Temporal hierarchical cluster analysis reveals that annual data series
have the closest relation with the summer data series. Further, the impact of temperature changes on winter wheat phenology
was determined using a phenology simulation performed with the model from the Decision Support System for Agrotechnology Transfer
v. 4.0.2.0 platform. Earlier occurrences of anthesis and maturity were noticed for several regions in the country. 相似文献
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Adina-Eliza Croitoru Dorin Drignei Iulian-Horia Holobaca Carmen Sofia Dragota 《Theoretical and Applied Climatology》2012,108(1-2):9-18
Characterizing climatic changes in the high-altitude mountain regions helps scientists and policy makers understand the effects of such changes on water resources, economic development, and the health of ecosystems. This paper proposes a change-point analysis to determine the time and magnitude of summer temperature changes in the summit areas of Romanian Carpathians between 1961 and 2007. Due to their altitude, massiveness, and position, Romanian Carpathians are an important barrier for different types of air masses between Western and Southeastern Europe. The results show that the change in summer temperatures occurred shortly after 1980. The average magnitude of this change is consistent with changes occurring in other parts of Southern Europe in the same time period although the magnitude of changes at individual weather stations may differ substantially. We aided our analysis by a statistical method based on regression models with serially correlated ARMA errors. 相似文献
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Kristin R. Wilson Joseph T. Kelley Arie Croitoru Michele Dionne Daniel F. Belknap Robert Steneck 《Estuaries and Coasts》2009,32(5):855-870
Salt pools are water-filled depressions common to north-temperate salt marshes. In Wells, ME, USA, cores reveal a unique salt
pool signature consisting of water-saturated dark-gray mud often containing fragments of Ruppia maritima. Cores through pool sediment reenter salt marsh peat, not tidal flat sediment, demonstrating that most pools are of secondary
origin. A principal component analysis of attribute data collected from 119 pools defines three distinct pool types: those
with (1) surrounding high-marsh vegetation and thick heavily undercut banks (40% of the variance), (2) surrounding low-marsh
vegetation and thicker slightly undercut banks (18% of the variance), and (3) surrounding low-marsh vegetation and less thick
moderately undercut banks, containing R. maritima and a surficial drainage (15% of the variance). Cores and spatiotemporal analyses of aerial photographs between 1962 and
2003 reveal dramatic salt marsh surface dynamism suggesting that salt pools influence the geomorphological evolution of coastal
marshes. 相似文献