نتایج جستجو برای: wildfires
تعداد نتایج: 2637 فیلتر نتایج به سال:
Ecosystems change in response to factors such as climate variability, invasions, and wildfires. Most records used to assess such change are based on short-term ecological data or satellite imagery spanning only a few decades. In many instances it is impossible to disentangle natural variability from other, potentially significant trends in these records, partly because of their short time scale...
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Characterization of aerosol particle episodes in Finland caused by wildfires in Eastern Europe J. V. Niemi, H. Tervahattu, H. Vehkamäki, J. Martikainen, L. Laakso, M. Kulmala, P. Aarnio, T. Koskentalo, M. Sillanpää, and U. Makkonen Department of Biological and Environmental Sciences, University of Helsinki, P.O. Box 27, FIN-00014 Helsinki, Finland Nordic Envicon Ltd., Koetilantie 3, FIN-00790 H...
[1] Concentrations of mercury (Hg) in soil profiles and vegetation were examined in unburned areas and in areas recently burned by wildfires of low, medium, and high fire severities in western Wyoming. Paired unburned and burned sampling sites with similar tree species composition, forest stand age, climate, and geological substrate were studied. Results indicate that Hg release from forest fir...
Several highly effective fire-adaptive traits first evolved among modern plants during the mid-Cretaceous, in response to the widespread wildfires promoted by anomalously high atmospheric oxygen (O2) and extreme temperatures. Serotiny, or long-term canopy seed storage, is a fire-adaptive strategy common among plants living in fire-prone areas today, but evidence of this strategy has been lackin...
This paper presents the results of an operational nationwide burnt area mapping service realized over Greece for the years 2007-2011, through the implementation of the so-called BSM_NOA dedicated method developed at the National Observatory of Athens for post-fire recovery management. The method exploits multispectral satellite imagery, such as Landsat-TM, SPOT, FORMOSAT-2, WorldView and IKONOS...
2Research Hydrologists and Computer Specialist, respectively, Pacific Southwest Forest and Range Experiment Station, Forest Service, U.S. Department of Agriculture, Arcata, California. Abstract: A simple Monte Carlo simulation evaluated the effect of several fire management strategies on soil slip erosion and wildfires. The current condition was compared to (1) a very intensive fuelbreak system...
[1] With climate change rapidly affecting northern forests and wetlands, mercury reserves once protected in cold, wet soils are being exposed to burning, likely triggering large releases of mercury to the atmosphere. We quantify organic soil mercury stocks and burn areas across western, boreal Canada for use in fire emission models that explore controls of burn area, consumption severity, and f...
The Burning Index (BI) is commonly used as a predictor of wildfire activity. An examination of data on the BI and wildfires in Los Angeles County, California from January 1976 to December 2000 reveals that although the BI is positively associated with wildfire occurrence, its predictive value is quite limited. Wind speed alone has a higher correlation with burn area than BI, for instance, and a...
Introduction Wildfires occur annually in Oregon, and the health risks of wildfire smoke are well documented1. Before implementing syndromic surveillance through Oregon ESSENCE, assessing the health effects of wildfires in real time was very challenging. Summer 2015 marked the first wildfire season with 60 of 60 eligible Oregon emergency departments (EDs) reporting to ESSENCE. The Oregon ESSENCE...
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