Discussion of the Opinion Paper “Hydrology and change” by Demetris Koutsoyiannis     

Arie Ben-Zvi 《水文科学杂志》2013,58(8)

  相似文献   

#Earthquake: Twitter as a Distributed Sensor System   总被引：10，自引：1，他引：9  

Andrew Crooks  Arie Croitoru  Anthony Stefanidis  Jacek Radzikowski 《Transactions in GIS》2013,17(1):124-147

Social media feeds are rapidly emerging as a novel avenue for the contribution and dissemination of information that is often geographic. Their content often includes references to events occurring at, or affecting specific locations. Within this article we analyze the spatial and temporal characteristics of the twitter feed activity responding to a 5.8 magnitude earthquake which occurred on the East Coast of the United States (US) on August 23, 2011. We argue that these feeds represent a hybrid form of a sensor system that allows for the identification and localization of the impact area of the event. By contrasting this with comparable content collected through the dedicated crowdsourcing ‘Did You Feel It?’ (DYFI) website of the U.S. Geological Survey we assess the potential of the use of harvested social media content for event monitoring. The experiments support the notion that people act as sensors to give us comparable results in a timely manner, and can complement other sources of data to enhance our situational awareness and improve our understanding and response to such events.  相似文献   

From the dawn of organic geochemistry (1933, 1938): Estrogenic substances in bituminous deposits and in the Dead Sea     

Arie Nissenbaum  Jürgen Rullkötter 《Organic Geochemistry》2011,42(5):498-501

We describe several pioneering organic geochemical studies from the 1930s on estrogenic substances isolated from various fossil fuels and bituminous materials and from water and sediments of the Dead Sea. The techniques employed were bioanalytical and not chemical. One of the studies, although not done on the same molecular level as his, precedes the work of Alfred Treibs, who is considered the father of organic geochemistry. By shedding light on a relatively unknown chapter of organic geochemistry, the roots of this discipline are shown to extend wider than usually recognized.  相似文献   

Comment on “Reassessment of rain experiments and operations in Israel including synoptic considerations” by Zev Levin,Noam Halfon and Pinhas Alpert [Atmos. Res. 97 (2010) 513–525]     

Arie Ben-Zvi  Daniel Rosenfeld  Amir Givati 《Atmospheric Research》2011,99(3-4):590-592

Levin et al. (referred here as LHA) made a sweeping conclusion that cloud seeding has been ineffective in Israel. They claimed that the results of the Israel-2 experiment could be fully ascribed to synoptic bias. However, the cross over analysis of Israel-2 has shown the same already in 1990 by Gabriel and Rosenfeld. While LHA only showed differences in the 850 hPa winds being stronger in the north seeded days of Israeli-2, Rosenfeld and Farbstein had already shown quantitatively in 1992 that this synoptic bias explains less than half of the indicated seeding effect in the north. Furthermore, accepting that a cross over design protects against synoptic bias means that the highly positive and statistically significant indicated seeding effect in Israeli-1, which was based on a cross-over design, cannot be explained by such synoptic bias. Instead, LHA completely ignored the Israeli-1 experiment.LHA's evaluation of the operational seeding used implied assumption that amounted to historical comparisons that have already been shown to be invalid, especially for the Israeli situation due to the decreasing trend of target–control ratio, especially over the eastern upper Galilee. For all of the above reasons, the conclusion of LHA that cloud seeding is ineffective in Israel is not supported by the data.Given the uncertainties, both physical and statistical, the Israeli water authority has embarked on the Israeli-4 randomized cloud seeding experiment, which is aimed at testing the hypothesis that cloud seeding might be affecting mainly the precipitation in the orographic clouds developing over the hills in the catchment of the Jordan River.  相似文献   

Letter to the Editor     

Arie Ben-Zvi 《水文科学杂志》2013,58(3)

  相似文献   

Stratigraphic and Ecophysical Characterizations of Salt Pools: Dynamic Landforms of the Webhannet Salt Marsh,Wells, ME,USA     

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   

The Dead Sea monster     

Arie Nissenbaum 《International Journal of Salt Lake Research》1992,1(2):1-8

  相似文献   

Detecting and mapping slums using open data: a case study in Kenya     

Ron Mahabir  Peggy Agouris  Anthony Stefanidis  Arie Croitoru  Andrew T. Crooks 《International Journal of Digital Earth》2020,13(6):683-707

ABSTRACT

The worldwide slum population currently stands at over one billion, with substantial growth expected in the coming decades. Traditionally, slums have been mapped using information derived mainly from either physical indicators using remote sensing data, or socio-economic indicators using census data. Each data source on its own provides only a partial view of slums, an issue further compounded by data poverty in less-developed countries. To overcome such issues, this paper explores the fusion of traditional with emerging open data sources and data mining tools to identify additional indicators that can be used to detect and map the presence of slums, map their footprint, and map their evolution. Towards this goal, we develop an indicator database for slums using open sources of physical and socio-economic data that can be used to characterize slum settlements. Using this database, we then leverage data mining techniques to identify the most suitable combination of these indicators for mapping slums. Using three cities in Kenya as test cases, results show that the fusion of these data can improve the mapping accuracy of slums. These results suggest that the proposed approach can provide a viable solution to the emerging challenge of monitoring the growth of slums.  相似文献   

Phosphorus in marine and non-marine humic substances     

Arie Nissenbaum 《Geochimica et cosmochimica acta》1979,43(12):1973-1978

The phosphorus content of marine humic acids (HA) is in the range of 0.1–0.2%. The C/P ratios of the HA are 300 to 400. Marine fulvic acids (FA) contain 0.4–0.8% P and have C/P ratios of 80 to 100. High molecular weight organic matter dissolved in pore waters (DOM) contains 0.5% P and has C/P of 90. The data suggest that during the formation sequence: Plankton → DOM → FA → HA → Kerogen, phosphorus is lost, mainly in the FA → HA (and possibly also in the HA → Kerogen) step. Diagenesis of sedimentary humic acids is accompanied by loss of phosphorus (as well as of nitrogen) to form HA with C/P ratios of 1000.Soil humic substances resemble marine humates in P content (0.3%) and soil FA's are about three to fivefold enriched in P relative to HA. C/P ratios are lower in soil HA (ca. 200) as compared with marine HA. Humic acids from diagenetic products such as peat and lignite are highly depleted in P. Rough calculations indicate that humate bound P may account for 20–50% of the organic phosphorus reservoir in sediments. The chemical speciation of this P is unknown, but lack of correlation with ash, Fe, Ca or Al content (in marine humates, at least) indicates that it is organically bound.  相似文献   

Asphalts, heavy oils, ozocerite and gases in the Dead Sea Basin     

A. Nissenbaum  M. Goldberg 《Organic Geochemistry》1980,2(3-4)

Solid, liquid and gaseous hydrocarbons occur throughout the Dead Sea Basin (Israel and Jordan) both in surface exposures and in drillings. The unaltered asphalts and heavy oils are characterized by very high sulfur content (ca. 11%) with δ³⁴S = +5% and δ¹³C = −28% to −29%, low content of n-paraffins, pristane to phytane ratio of 0.5 and by containing almost exclusively VO-porphyrins. The distribution of n-paraffins in samples from deep sources shows a smooth enveloped miximizing at C_15–20. Surface and shallow samples show clear evidence of biodegradation. The ozokerite, known only from the east side of the basin, is composed primarily of long chain n-paraffins with a maximum at C₃₉. The gases known from the southern margin of the basin are composed mostly of methane.The source for the bitumens is unknown. Two hypotheses are discussed. The first is that the asphalts and heavy oils represent an alteration products of crude oil which migrated into the basin or which might have been generated in the basin itself. The second hypothesis favors an origin from low temperature alteration of organic matter from a thermally immature source.  相似文献