Search results for "Summer"

Variability of the African convection centre as viewed by outgoing longwave radiation records and relationships with sea-surface temperature patterns

1995

International audience; The main African convection centre (ACC) is delimited by the 5"-square areas with outgoing longwave radiation less than 235 W m-' in the domain 17.5°N-17.5"S and 18"W-46"E. Four parameters (latitude and longitude of the centre of gravity, mean intensity, and extension) were analysed during the period June 1974 to December 1991. The relationships between the variability of the ACC and the main sea-surface temperature (SST) patterns were then studied. Correlation and composite analyses demonstrate that the first principal component of SST, representing mainly the variability of the eastern and the central tropical Pacific, is associated strongly with the extension and …

CISV-kesäkylä kulttuurienvälisenä kasvattajana ja kokemuksellisen oppimisen mahdollistajana : kesäkylän vaikutukset 12-13-vuotiaiden oppilaiden koulu…

2009

CH4 oxidation in a boreal lake during the development of hypolimnetic hypoxia

2020

AbstractFreshwater ecosystems represent a significant natural source of methane (CH4). CH4 produced through anaerobic decomposition of organic matter (OM) in lake sediment and water column can be either oxidized to carbon dioxide (CO2) by methanotrophic microbes or emitted to the atmosphere. While the role of CH4 oxidation as a CH4 sink is widely accepted, neither the magnitude nor the drivers behind CH4 oxidation are well constrained. In this study, we aimed to gain more specific insight into CH4 oxidation in the water column of a seasonally stratified, typical boreal lake, particularly under hypoxic conditions. We used 13CH4 incubations to determine the active CH4 oxidation sites and the …

Pasākuma tīmekļa vietnes izstrāde

2015

Kvalifikācijas darba ietvaros tika izstrādāta pasākuma tīmekļa vietne. Tā ir tīmekļa vietne, kas ļauj lietotājiem uzzināt informāciju par “Summer Lab 2015” pasākumu, pieteikties tam un apskatīt pasākuma emuāru, kā arī lapas administratoriem pārskatīt pieteikušos potenciālos pasākuma apmeklētājus un pārvaldīt emuāra saturu. Lai pieteiktos pasākumam nav nepieciešama reģistrācija, bet lai pārvaldītu tīmekļa vietnes saturu, tā ir nepieciešama. Pieteikšanās pasākumam ir vienkāršota līdz nepieciešamās informācijas ievadei. Darbā izmantotas tādas tehnoloģijas kā Laravel 4.2 (PHP ietvars), PHP, MySQL, HTML5, Mailigen API, CSS, JavaScript un Jquery. Atslēgas vārdi: Summer Lab, pasākums, emuārs, tīme…

Influence of the Madden-Julian Oscillation on Southern African summer rainfall

2007

Rain-causing mechanisms over Southern Africa (south of 15˚S) involve both tropical and temperate dynamics. Most studies focused on the synoptical timescale, while the intraseasonal (20-120 days) variability has more been neglected to date. This study aims at determining whether the dominant mode of intraseasonal variability in the Tropics, namely the Madden-Julian Oscillation (MJO), has a significant impact on Southern African rainfall and associated atmospheric dynamics. The examination of outgoing longwave radiation (OLR) over Southern Africa shows indeed significant intraseasonal fluctuations at the 30-60 day timescale, i.e. in the pe- riods that are typically reminiscent of the MJO. In ord…

Trace gas composition in the Asian summer monsoon anticyclone: a case study based on aircraft observations and model simulations

2017

We present in situ measurements of the trace gas composition of the upper tropospheric (UT) Asian summer monsoon anticyclone (ASMA) performed with the High Altitude and Long Range Research Aircraft (HALO) in the frame of the Earth System Model Validation (ESMVal) campaign. Air masses with enhanced O3 mixing ratios were encountered after entering the ASMA at its southern edge at about 150 hPa on 18 September 2012. This is in contrast to the presumption that the anticyclone's interior is dominated by recently uplifted air with low O3 in the monsoon season. We also observed enhanced CO and HCl in the ASMA, which are tracers for boundary layer pollution and tropopause layer (TL) air or stratosp…

Design, Building up and First Results of Three Monitored Green Coverings Over a University Department Building

2015

Abstract A viable solution to reducing the buildings’ energy demand is the implementation of green coverings that have been demonstrated to improve the envelope performance, especially in summer season. Anyway, to apply computer models analyzing the energy performance of buildings equipped with such components, the knowledge of specific parameters is needed. Among these, the fractional vegetation coverage and leaf area index are of great importance. By means of an experimental facility, first results of the evaluation of these foliage-related parameters for five types of vegetation are presented.

Low-altitude outbreaks of human fascioliasis related with summer rainfall in Gilan province, Iran

2011

Following human fascioliasis outbreaks in 1988 and 1999 in Gilan province, northern Iran, efforts are now made to shed light on the seasonal pattern of fascioliasis transmission in this endemic area, taking into account snail host populations, climatic conditions and human cases. Populations of the intermediate host snail (Lymnaea spp.) peak in May and November, while there is a fourfold increase in the rate of human fascioliasis in February compared to that of September. Transmission is likely to occur mainly in late autumn and sporadically in late spring. Rainfall, seasonally analysed in periods of 3 years, indicates that accumulated summer rainfall may be related with the 1988 and 1999 h…

Insensitivity of Tree-Ring Growth to Temperature and Precipitation Sharpens the Puzzle of Enhanced Pre-Eruption NDVI on Mt. Etna (Italy)

2017

On Mt. Etna (Italy), an enhanced Normalized Difference in Vegetation Index (NDVI) signature was detected in the summers of 2001 and 2002 along a distinct line where, in November 2002, a flank eruption subsequently occurred. These observations suggest that pre-eruptive volcanic activity may have enhanced photosynthesis along the future eruptive fissure. If a direct relation between NDVI and future volcanic eruptions could be established, it would provide a straightforward and low-cost method for early detection of upcoming eruptions. However, it is unclear if, or to what extent, the observed enhancement of NDVI can be attributed to volcanic activity prior to the subsequent eruption. We conse…

Intraseasonal rainfall variability over Madagascar

2016

International audience; Using daily rain-gauge records for Madagascar and nearby islands, this paper investigates rainfall intraseasonal variability at local and regional scales during the austral summer season (November–February), as well as the respective influences of recurrent convective regimes over the South-West Indian Ocean (SWIO) and the Madden-Julian Oscillation (MJO). Our results show a general consistency between local-scale rainfall variability in Madagascar and regional-scale features of climate variability. The influence of Tropical-Temperate Troughs in their mature phase and/or their easternmost locations is first underlined. The development of such systems over Southern Afr…