503 research outputs found

    The Occurrence of Cold Spells in the Alps Related to ClimateChange

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    Author to whom correspondence should be addressed; E-Mail: [email protected];Tel.: +39-011-670-7891; Fax: +39-011-658-444.Received: 23 June 2010; in revised form: 27 July 2010 / Accepted: 27 July 2010 /Published: 2 August 2010Abstract: Climate change is not only a likely prospect for the end of this century, butit is already occurring. Part of the changes will include global warming and increasingtemperature variability, both at global and regional scales. This increased variability wasinvestigated in this paper from the point of view of the occurrence of cold spells in theAlps in the future climate (2071–2100), compared with the present climate (1961–1990).For this purpose, a regionalisation of the climate change effects was performed within theAlps. To avoid possible errors in the estimate of the 2m air temperature, the analysis wasperformed on the soil surface temperature. To get realistic values for this variable, a landsurface scheme, UTOPIA, has been run on the selected domain, using the output of theRegional Climate Model (RegCM3) simulations as the driving force. The results show that,in general, the number of cold breaks is decreasing over the Alps, due to the temperatureincrement. However, there are certain zones where the behaviour is more complicated. Theanalysis of the model output also allowed a relationship to be found between the numberof cold breaks and their duration. The significance of these results over the whole area wasassessed.Keywords: cold spells; climate change; LSPM; UTOPIA; climate extreme

    Benign metastasizing leiomyoma of the lung

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    Benign leiomyomas of the uterus are uncommonly found in association with benign smooth muscle tumors beyond the confines of the uterus. Benign metastasizing leiomyoma (BML) is a rare disease in which the lung is described to be the most afflicted extrauterine organ. We present a brief review of the literature, along with case reports for four patients who were followed up after resection of a pulmonary lesion or after pathological confirmation by biopsy. The clinical course of BML varies from chronic asymptomatic appearance to rapid progression, leading to respiratory failure and death. Our BML patients did not complain of pulmonary symptoms, such as cough, dyspnea, or chest tightness. Pathology revealed benign leiomyomas with no atypia and mitotic activity <5 per 10 high-power field. Immunohistochemical staining was positive for actin and desmin. A standard treatment for BML has not yet been established. Because of the hormone-sensitive characteristics of BML, treatments are based on hormonal manipulation along with either surgical or medical oophorectomy. Benign metastasizing leiomyoma can be observed in postmenopausal women. We observed four patients who did not receive adjuvant hormonal therapy because they were postmenopausal or perimenopausal. All patients are still healthy and show no evidence of recurrence or progression of the disease

    Inter- and Intra-Annual Variability of Vegetation in the Northern Hemisphere and Its Association with Precursory Meteorological Factors

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    Determination of phenological variation is one of the most critical challenges in dynamic vegetation modeling, given the lack of a strong theoretical framework. Previous studies generally focused on the timing of a phenological event (e.g., bud-burst or onset of growing season) and its atmospheric prompts, but not on the interactive variations across phenological stages. This study, therefore, investigated the inter- and intra-annual variability existing in all the phenological stages and the relations of the variability with four meteorological variables (surface temperature (Ts), shortwave radiation (SW ), vapor pressure deficit (VPD), and precipitation (PRCP)) using a 25-year (1982-2006) dataset of leaf area index (LAI) from the Advanced Very High Resolution Radiometer (AVHRR). Our six study sites of each 4 degree x 4 degree grids (mixed forest in China, deciduous needle-leaf forest in Siberia, evergreen needle-leaf forest in western Canada, grass in Gobi, and crops in the Central United States and southeastern Europe) include various vegetation types, local climates, and land-use types in the mid-latitudes of the northern hemisphere. Empirical orthogonal function (EOF) analysis with detrended LAI anomalies identified the two leading EOF modes that account for the amplitude and phase of the monthly LAI variations. The inter-annual correlation between the principle components (PCs) of the two modes and the meteorological variables for spring and summer showed that the amplitude and phase modes (AM and PM, respectively) were affected by different dominant meteorological factors. Over most of the study regions, AM was positively correlated with PRCP and negatively with Ts, SW, and VPD,while PMwas predominantly positively correlated with Ts. The contrasting responses of the two EOFmodes to Ts reflect environmental limitations on plant growth such as early start of growth, but with a reduced value of maximum LAI in a year with a warm spring. In addition, insignificant correlations between AMand PRCP, as well as negative correlations between PM and PRCP, in the crop regions suggest that human interventions such as advanced irrigation systems also play a key role in vegetative activity

    Impact of Vegetation on Land-Atmosphere Coupling Strength and Its Implication for Desertification Mitigation over East Asia

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    Desertification of the East Asian drylands and the consequent dust transport have been serious concerns for adjacent Asian countries as well as the western United States. Tree planting has been considered one applicable strategy to mitigate the desertification. However, the desired effect of the tree planting would not be brought to fruition unless the newly planted trees change the coupling characteristics between the land and the atmosphere. Based on this perception, we attempt to clarify the effects of vegetation on the coupling strength between the atmosphere and land surface, and we suggest the most efficient areas of tree planting for desertification mitigation in East Asia. Using regional vegetation-atmosphere coupled model simulations, coupling strength with and without vegetation was computed and compared with each other. An increased vegetation fraction reduces the coupling strength in June, July, and August (JJA), primarily due to decreased evapotranspiration variability. This effect is pronounced over the Manchurian Plains and the highly populated areas of Beijing and Tianjin. The reduced coupling strength tends to weaken feedback between soil moisture and precipitation as a maintenance mechanism of warm season droughts in the midlatitudes and subsequently decrease the probability of droughts, a finding that is reflected in the enhanced JJA mean soil moisture. However, some drylands like the eastern edges of the Gobi desert present marginal or even opposite changes in coupling strength, meaning a limited effect of vegetation on relieving droughts. Therefore, given limited financial and human resources, acupuncture-like afforestation, i.e., concentrated tree planting in a particular region where the coupling strength can be substantially reduced by vegetation, is an effective strategy to secure long-standing desertification mitigation

    Assessment of satellite rainfall nowcasting based on extrapolation technique

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    Póster presentado en: 3rd European Nowcasting Conference, celebrada en la sede central de AEMET en Madrid del 24 al 26 de abril de 2019

    Soil Surface Energy and Water Budgets during a Monsoon Season in Korea

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    Abstract In this study, attention has been focused on the climatology of some variables linked to the turbulent exchanges of heat and water vapor in the surface layer during a summer monsoon in Korea. In particular, the turbulent fluxes of sensible and latent heat, the hydrologic budget, and the soil temperatures and moistures have been analyzed. At large scale, because the measurements of those data are not only fragmentary and exiguously available but also infeasible for the execution of climatologic analyses, the outputs of a land surface scheme have been used as surrogate of observations to analyze surface layer processes [this idea is based on the methodology Climatology of Parameters at the Surface (CLIPS)] in the Korean monsoonal climate. Analyses have been made for the summer of 2005. As a land surface scheme, the land surface process model (LSPM) developed at the University of Torino, Italy, has been employed, along with the data collected from 635 Korean meteorological stations. The LSPM predictions showed good agreement with selected observations of soil temperature. Major results show that, during the rainfall season, soil moisture in the first tenths of centimeters frequently exceeds the field capacity, whereas most of the rainfall is "lost" as surface runoff. Evapotranspiration is the dominant component of the energy budget, sometimes even exceeding net radiation, especially during the short periods between the precipitation events; in these periods, daily mean soil temperatures are about 28°C or even more. The Gyeonggi-do region, the metropolitan area surrounding Seoul, shows some particularities when compared with the neighboring regions: solar radiation and precipitations are lower, causing high values of sensible heat flux and soil temperatures, and lower values of latent heat flux and soil moistures

    Attribution of the 2015 record high sea surface temperatures over the central equatorial Pacific and tropical Indian Ocean

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    This study assessed the anthropogenic contribution to the 2015 record-breaking high sea surface temperatures (SSTs) observed in the central equatorial Pacific and tropical Indian Ocean. Considering a close link between extreme warm events in these regions, we conducted a joint attribution analysis using a fraction of attributable risk approach. Probability of occurrence of such extreme anomalies and long-term trends for the two oceanic regions were compared between CMIP5 multi-model simulations with and without anthropogenic forcing. Results show that the excessive warming in both regions is well beyond the range of natural variability and robustly attributable to human activities due to greenhouse gas increase. We further explored associated mechanisms including the Bjerknes feedback and background anthropogenic warming. It is concluded that background warming was the main contribution to the 2015 extreme SST event over the central equatorial Pacific Ocean on a developing El Niño condition, which in turn induced the extreme SST event over the tropical Indian Ocean through the atmospheric bridge effect.113Ysciescopu

    Influence of non-feedback variations of radiation on the determination of climate feedback

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    Recent studies have estimated the magnitude of climate feedback based on the correlation between time variations in outgoing radiation flux and sea surface temperature (SST). This study investigates the influence of the natural non-feedback variation (noise) of the flux occurring independently of SST on the determination of climate feedback. The observed global monthly radiation flux is used from the Clouds and the Earth's Radiant Energy System (CERES) for the period 2000–2008. In the observations, the time lag correlation of radiation and SST shows a distorted curve with low statistical significance for shortwave radiation while a significant maximum at zero lag for longwave radiation over the tropics. This observational feature is explained by simulations with an idealized energy balance model where we see that the non-feedback variation plays the most significant role in distorting the curve in the lagged correlation graph, thus obscuring the exact value of climate feedback. We also demonstrate that the climate feedback from the tropical longwave radiation in the CERES data is not significantly affected by the noise. We further estimate the standard deviation of radiative forcings (mainly from the noise) relative to that of the non-radiative forcings, i.e., the noise level from the observations and atmosphere–ocean coupled climate model simulations in the framework of the simple model. The estimated noise levels in both CERES (>13 %) and climate models (11–28 %) are found to be far above the critical level (~5 %) that begins to misrepresent climate feedback.Korea. Meteorological Administration. Research and Development Program (grant CATER 2012–3064)National Research Foundation of Korea (MSIP) (2009-83527

    Comparison between a reanalyzed product by 3-dimensional variational assimilation technique and observations in the Ulleung Basin of the East/Japan Sea

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    Author Posting. © Elsevier B.V., 2009. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Journal of Marine Systems 78 (2009): 249-264, doi:10.1016/j.jmarsys.2009.02.017.Reanalyzed products from a MOM3-based East Sea Regional Ocean Model with a 3- dimentional variational data assimilation module (DA-ESROM), have been compared with the observed hydrographic and current datasets in the Ulleung Basin (UB) of the East/Japan Sea (EJS). Satellite-borne sea surface temperature and sea surface height data, and in-situ temperature profiles have been assimilated into the DA-ESROM. The performance of the DA-ESROM appears to be efficient enough to be used in an operational ocean forecast system. Comparing with the results from Mitchell et al. (2005a), the DA-ESROM fairly well simulates the high variability of the Ulleung Warm Eddy and Dok Cold Eddy as well as the branching of the Tsushima Warm Current in the UB. The overall root-mean-square error between 100m temperature field reproduced by the DA-ESROM and the observed 100-dbar temperature field is 2.1°C, and the spatially averaged grid-to-grid correlation between the two temperature fields is high with a mean value of 0.79 for the intercomparison period. The DA-ESROM reproduces the development of strong southward North Korean Cold Current (NKCC) in summer consistent with the observational results, which is thought to be an improvement of the previous numerical models in the EJS. The reanalyzed products show that the NKCC is about 35 km wide, and flows southward along the Korean coast from spring to summer with maximum monthly mean volume transport of about 0.8 Sv in August-September.The major part of this works was conducted with financial support by Agency for Defense Development under the contract UD031003AD. The first and seventh authors were supported at the final stage of this work by KORDI’s research projects (PE9830Q and PG47100). The second author was supported by EAST-I Program of the Ministry of Maritime Affairs and Fisheries
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