Impacts of temperature anomalies on mortality of benthic organisms in the Adriatic Sea          下载免费PDF全文

Petar Kružić  Petra Rodić  Aleksandar Popijač  Maya Sertić 《Marine Ecology》2016,37(6):1190-1209

Recurrent climate‐induced mass mortality episodes have been recorded in the Mediterranean Sea over the past 15 years, affecting rocky benthic communities. In this study, we provide for the first time a report on the annual mortality events of benthic sessile invertebrates occurring in the eastern part of the Adriatic Sea. Over the course of 14 consecutive years, we studied the sea temperature gradient to a depth of 40 m and found an abnormal summer warming trend and an increased frequency of above‐average temperatures. Mortality events were recorded in the summers of 10 observed years, in particular in 2009, when the highest mortality rates were recorded. Late in summer 2009, extensive mass mortality of sessile invertebrates was observed in the entire Eastern Adriatic Sea. We performed an analysis of selected target benthic species associated with mass mortality events with inter‐regional differences in hydrological and temperature conditions. We were able to characterize the mortality event by studying five areas covering the northern, central and southern regions of the Eastern Adriatic Sea. The degree of impact on each study area was quantified at 28 sites by estimating the proportion of affected target species. According to the obtained data, the northern sites (Cres area) were the least affected, whereas sites in the Central and Southern Adriatic [Tela??ica and Lastovo Nature Parks, Mljet National Park (NP)] displayed the highest impact. In summer 2009, sea surface temperatures reached values of 28 °C in the Cres area and 30 °C in Mljet NP. These thermal conditions were concomitant with moderate to severe mass mortalities of benthic populations. Mass mortality events reached depths of 45 m in most parts of the affected areas. Amongst studied species, the scleractinian coral and gorgonian populations suffered the most extensive damage during the mass mortality events.  相似文献   

Opening a new window to other worlds with spectropolarimetry     

Maren Mohler  Johannes Bühl  Stephen Doherty  Siegfried Eggl  Vera Theresa Eybl  François Farago  Aleksandar Jaćimović  Lars Hunger  Nynne L. B. Lauritsen  David Ludena  Martina Meisnar  Alexander Reissner  Nicolas Sarda  Benjamin Toullec  Meritxell Viñas Tió 《Experimental Astronomy》2010,28(2-3):101-135

A high level of diversity has already been observed among the planets of our own Solar System. As such, one expects extrasolar planets to present a wide range of distinctive features, therefore the characterisation of Earth- and super Earth-like planets is becoming of key importance in scientific research. The Search (Spectropolarimetric Exoplanet AtmospheRe CHaracerisation) mission proposal of this paper represents one possible approach to realising these objectives. The mission goals of Search include the detailed characterisation of a wide variety of exoplanets, ranging from terrestrial planets to gas giants. More specifically, Search will determine atmospheric properties such as cloud coverage, surface pressure and atmospheric composition, and may also be capable of identifying basic surface features. To resolve a planet with a semi major axis of down to 1.4 AU and 30 pc distant Search will have a mirror system consisting of two segments, with elliptical rim, cut out of a parabolic mirror. This will yield an effective diameter of 9 m along one axis. A phase mask coronagraph along with an integral spectrograph will be used to overcome the contrast ratio of star to planet light. Such a mission would provide invaluable data on the diversity present in extrasolar planetary systems and much more could be learned from the similarities and differences compared to our own Solar System. This would allow our theories of planetary formation, atmospheric accretion and evolution to be tested, and our understanding of regions such as the outer limit of the Habitable Zone to be further improved.  相似文献   

Inter-decadal Variability in Phytoplankton Community in the Middle Adriatic (Kaštela Bay) in Relation to the North Atlantic Oscillation     

Živana Ninčević Gladan  Ivona Marasović  Branka Grbec  Sanda Skejić  Mia Bužančić  Grozdan Kušpilić  Slavica Matijević  Frano Matić 《Estuaries and Coasts》2010,33(2):376-383

Evaluation of a 45-year data set of primary production (PP), a 30-year data set of phytoplankton biomass, and a 51-year data set of species composition shows an increase of phytoplankton biomass and abundance in the period from the mid-1980s to the mid-1990s. Phytoplankton biomass showed bimodal seasonal cycles, with winter and spring maxima, which did not change over the past 30 years. Diatoms were the most abundant functional group and they prevailed during the colder part of the year while the dinoflagellate contribution to the phytoplankton community increased in the warmer period from May to August. Diatoms showed a significant negative correlation with sea surface temperature (SST), while dinoflagellates were positively correlated with SST. An increase of phytoplankton abundance, particularly dinoflagellate, in the period from the mid-1980s to the mid-1990s coincided with years characterized by a high North Atlantic Oscillation (NAO) index. Primary production and chlorophyll a concentration in the spring period were negatively correlated with the NAO winter (DJFM) index, probably caused by increased precipitation associated with a low or negative NAO index. PP in winter during the mixing period was positively related to the NAO winter index associated with higher temperatures and dry conditions which brought more clear days and increased input of solar radiation.  相似文献   

An analysis of the FIR/RADIO continuum correlation in the small Magellanic cloud     

Howard Leverenz  Miroslav D. Filipović 《Astrophysics and Space Science》2013,343(1):301-317

The local correlation between far-infrared (FIR) emission and radio-continuum (RC) emission for the Small Magellanic Cloud (SMC) is investigated over scales from 3 kpc to 0.01 kpc. Here, we report good FIR/RC correlation down to ～15 pc. The reciprocal slope of the FIR/RC emission correlation (RC/FIR) in the SMC is shown to be greatest in the most active star forming regions with a power law slope of ～1.14 indicating that the RC emission increases faster than the FIR emission. The slope of the other regions and the SMC are much flatter and in the range of 0.63–0.85. The slopes tend to follow the thermal fractions of the regions which range from 0.5 to 0.95. The thermal fraction of the RC emission alone can provide the expected FIR/RC correlation. The results are consistent with a common source for ultraviolet (UV) photons heating dust and Cosmic Ray electrons (CRe^?s) diffusing away from the star forming regions. Since the CRe^?s appear to escape the SMC so readily, the results here may not provide support for coupling between the local gas density and the magnetic field intensity.  相似文献   

Spatial and temporal analysis of dry spells in Croatia   总被引：3，自引：1，他引：2  

K. Cindrić  Z. Pasarić  M. Gajić-Čapka 《Theoretical and Applied Climatology》2010,102(1-2):171-184

Systematic statistical analysis of dry day sequences, which are defined according to 0.1, 1, 5 and 10 mm of precipitation-per-day thresholds, is performed on seasonal and yearly basis. The data analysed come from 25 Croatian meteorological stations and cover the period 1961–2000. Climatological features of the mean and maximum dry spell durations, as well as the frequency of long dry spells (>20 days) are discussed. The results affirm the three main climatological regions in Croatia, with the highlands exhibiting shorter dry spells than the mainland, and the coastal region exhibiting longer dry spells. The prevailing positive trend of both mean and maximal durations is detected during winter and spring seasons, while negative trend dominate in autumn for all thresholds. Positive field significant trends of mean dry spell duration with 5 and 10 mm thresholds are found during spring and the same is valid for annual maximum dry spell duration with a 10 mm threshold. It is found that the Discrete Autoregressive Moving Average (DARMA(1,1)) model can be used to estimate the probabilities of dry spells in Croatia that are up to 20–30 days long.  相似文献   

Dependence of accumulated precipitation on cloud drop size distribution     

Mladjen Ćurić  Dejan Janc  Katarina Veljović 《Theoretical and Applied Climatology》2010,102(3-4):471-481

Convective precipitation is the main cause of extreme rainfall events in small areas. Its primary characteristics are both large spatial and temporal variability. For this reason, the monitoring of accumulated precipitation fields (liquid and solid components) at the surface is difficult to carry out through the use of rain gauge networks or remote-sensing observations. Alternatively, numerical models seem to be the most powerful tool in simulating convective precipitation for various analyses and predictions. Due to a lack of comparisons between modelled and observed precipitation characteristics over a long period of time, we focus our research on comparisons between observations and three model samples of accumulated convective precipitation over a particular study area. We use a numerical cloud model with two model schemes involving the unified Khrgian–Mazin size distribution of cloud drops and a model scheme involving a monodisperse cloud droplet spectrum and the Marshall–Palmer size distribution for raindrops, respectively. For comparison, we have selected a study area with a sounding site. Our analysis shows that the model version with the Khrgian–Mazin size distribution exhibits a better agreement with the observed mean, median and range of extreme values of accumulated convective precipitation. Model simulations with the Khrgian–Mazin size distribution most closely match observations, with a correlation coefficient of 0.91. Use of the Marshall–Palmer size distribution, on the other hand, systemically underestimates the observed precipitation and has the lowest correlation coefficient among the methods, 0.83. Such an investigation is crucial to improve predictions of accumulated convective precipitation for various climatological and hydrological analyses and predictions.  相似文献   

ERA-40-aided assessment of the atmospheric influence on satellite retrieval of Adriatic Sea surface temperature     

Igor Tomažić  Milivoj Kuzmić 《Meteorology and Atmospheric Physics》2009,104(1-2):37-51

The aim of this work is assessment of regional atmospheric influence on satellite derivation of Adriatic Sea surface temperature (SST). To this end the European Centre for Medium-Range Weather Forecast (ECMWF) ERA-40 reanalysis dataset has been employed to provide the temperature and humidity profiles and surface data, while the RTTOV 8.7 radiative transfer model was used to calculate the top-of-atmosphere brightness temperatures for the advanced very high-resolution radiometer (AVHRR) channels. Ten ERA-40 grid points over the Adriatic Sea were used in the analysis, providing 29,590, 00 UTC and 12 UTC, clear-sky profiles. Climatological analysis of the ERA-40 profiles demonstrated distinct seasonal variability over the Adriatic Sea. Seasonality noted in the temperature and specific humidity profiles also evinced in the atmospheric transmittance, thermal channels temperature deficit, and derived γ and ρ parameters. A multivariate analysis was applied to relate the simulated top-of-atmosphere brightness temperatures to the Adriatic SSTs in order to generate exploratory sets of SST retrieval coefficients. All derived coefficient sets exhibited smaller noise amplification factor than the global counterpart. A test comparison of satellite-derived SST with an 11-month in situ SST series showed than locally derived coefficients provide smaller scatter (improved precision), and skin-centred bias that requires additional adjustment. Almost identical SST residual and error metric was obtained with seasonally adjusted classical split-window coefficients and with coefficients explicitly accommodating water-vapor dependence. Comparison with data reinforces the notion that the atmosphere over the Adriatic may exhibit variability that cannot be fully accommodated by globally adjusted correction.  相似文献   

Changes in extreme daily winter and summer temperatures in Belgrade   总被引：1，自引：1，他引：0  

M. Unkašević  I. Tošić 《Theoretical and Applied Climatology》2009,95(1-2):27-38

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An analytical representation of ephemeris data     

B. Javanović 《Celestial Mechanics and Dynamical Astronomy》1988,45(1-3):317-320

An algebraic method for the resolution of tabulated function into a class of elementary functions is examined on the high precision ephemeris data from the JPL DE 200.  相似文献   

Croatia in the continental traffic network of Europe     

Adolf Malić  Damir Bozičević 《GeoJournal》1996,38(4):463-468

Croatia is located on the southeastern edge of Central Europe (Ruppert 1995), between the navigable Danube River and the Adriatic Sea, so that participates not only in continental traffic, but in the maritime and river traffic of Europe as well.Although the transit position of Croatia is very favorable, transportation itself has unfortunately not been developed in accordance with these advantages. This is a result of the social-economic, especially political, development of the region in the course of its history. Unfortunately, politics also influences the selection of transit routes in this part of Europe today. With the break-up of socialist states, particularly the former Yugoslavia, new states have appeared which are seeking their place in the European traffic network. Because of the momentarily uncertain political circumstances, the construction of some transit routes in Croatia have not been foreseen in international developmental plans for continental transit, despite the fact that they would be logically expected given the advantages of their position.  相似文献