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Heat waves over Central Europe in ALADIN-Climate/CZ regional climate model: evaluation and future projections
Lhotka, Ondřej; Farda, A.; Kyselý, Jan
2015 - anglický
We evaluated a simulation of Central European heat waves and analysed possible changes of their characteristics in the future climate using the ALADIN-Climate/CZ regional climate model with 25km horizontal grid spacing. Lateral boundary conditions were provided by the ARPEGE global climate model, using historical forcing and the SRES A1B scenario. Observed data were taken from the E-OBS gridded data set. Heat waves were evaluated over 1970−1999 and changes in their characteristics were assessed for 2020−2049. Their definition is based on exceedance of the 90th percentile of summer daily maximum temperature calculated separately for modelled and observed data. ALADIN-Climate/CZ simulates characteristics for the recent climate quite well, especially the overall severity of heat waves. In contrast, temperature amplitude was considerably overestimated. This model projects an increase in overall heat wave severity by a factor of 2 to 3 in the future climate, primarily driven by an increasing number of events. The study shows that ALADIN-Climate/CZ is generally capable of simulating Central European heat waves, which gives more credibility to model projections of future heat waves.
Klíčová slova:
heat waves; regional climate models; ALADIN-Climate/CZ
Dokument je dostupný na externích webových stránkách.
Heat waves over Central Europe in ALADIN-Climate/CZ regional climate model: evaluation and future projections
We evaluated a simulation of Central European heat waves and analysed possible changes of their characteristics in the future climate using the ALADIN-Climate/CZ regional climate model with 25km ...
Multi-band Whistler-mode Chorus Emissions Observed by the Cluster Spacecraft
Macúšová, Eva; Santolík, Ondřej
2011 - anglický
Whistler-mode chorus emissions are one of the most significant mechanisms causing the acceleration of electrons in the outer Van Allen radiation belt to relativistic energies. They consist of individual wave packets divided into two frequency bands separated close to the source region by a gap at 1/2 of the electron cyclotron frequency (fce). This configuration is called banded chorus and it is correlated with magnetic activity. Landau damping is one of the possible explanations describing the existence of the gap. On the other hand, the role of ducts in its formation was also discussed. We present several events of chorus combined with noisy or shapeless chorus-like emissions that are arranged in three or more frequency bands with two or more gaps and are observed mostly in a magnetic latitude range from 3 to 10 degrees on the both sides of the equator. We investigate possible influences of the magnetic local time (MLT), the Kp index, the McIlwain parameter and the plasma density on the formation of these multi-band emissions.
Klíčová slova:
Cluster spacecraft; Whistler-mode chorus emissions
Dokument je dostupný na externích webových stránkách.
Multi-band Whistler-mode Chorus Emissions Observed by the Cluster Spacecraft
Whistler-mode chorus emissions are one of the most significant mechanisms causing the acceleration of electrons in the outer Van Allen radiation belt to relativistic energies. They consist of ...
Pollutant concentration in cloud water in relation to the air flow direction at 850 hPa level
Fišák, Jaroslav; Řezáčová, Daniela; Fottová, D.; Potužníková, Kateřina
2004 - anglický
The negative impact of pollutant concentration in fog water on the environment and consequently on the health of population was proved by numerous studies. Recently, the investigation has been focused on the pollutant concentration in fog water from several points of view. In this paper we briefly summarizethe results of clustering the fog water samples according to the enrichment factor and establishing the link of clusters and the air flow at 850 hPa level Negativní dopad koncentrací polutantů v mlžné vodě na přírodní prostředí a následně na zdravotní stav populace byly ukázány v řadě studií. Výzkum koncentací polutantů v mlžné vodě byl prováděn s různým zaměřením. V tomto příspěvku jsou stručně shrnuty výsledky shlukování vzorků mlžné vody v závislosti na faktoru obohacení a stanovení závislosti shluků na proudění vzduchu v hladině 850 hPa
Klíčová slova:
pollutant concentration; fog water; environment
Dokument je dostupný na externích webových stránkách.
Pollutant concentration in cloud water in relation to the air flow direction at 850 hPa level
The negative impact of pollutant concentration in fog water on the environment and consequently on the health of population was proved by numerous studies. Recently, the investigation has been focused ...
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