Upper ocean manifestations of a reducing meridional overturning circulation

Most climate models predict a slowing down of the Atlantic Meridional Overturning Circulation during the 21st century. Using a 100year climate change integration of a high resolution coupled climate model, we show that a 5.3Sv reduction in the deep southward transport in the subtropical North Atlantic is balanced solely by a weakening of the northward surface western boundary current, and not by an increase in the southward transport integrated across the interior ocean away from the western boundary. This is consistent with Sverdrup balance holding to a good approximation outside of the western boundary region on decadal time scales, and may help to spatially constrain past and future change in the overturning circulation. The subtropical gyre weakens by 3.4Sv over the same period due to a weakened wind stress curl. These changes combine to give a net 8.7Sv reduction in upper western boundary transport. © 2012. American Geophysical Union. All Rights Reserved

Production Technology and Competitiveness In the Hungarian Manufacturing Industry

Following the big transformations of the 1990s, enterprise structure and technological level seem to have become stabilised in Hungary. Under these circumstances it is especially interesting to identify the elements responsible for competitiveness in general, and the role technology plays in development in particular, according to managers experienced in production and marketing. This empirical study – based on in-depth interviews and field research – summarises characteristics of the technological level in the sectors examined, role of technology and labour in production, effects of foreign direct investment, relations between competition and firm-level factors determining competitiveness, and concludes by summing up those most frequently mentioned proposals that should be incorporated into economic policy according to managers. Main findings indicate that more qualified, more intensive and cheaper labour can be substituted for high technology. The competitiveness of an enterprise is not determined by technology alone, but rather by a combination of technology, the parameters of available labour and the costs of investment increasing productivity. The insufficiency of inter-company relations, together with a shortage of available assets necessary for investment constitute the major threat undermining the competitiveness of enterprises in present-day Hungary

The present and future system for measuring the Atlantic meridional overturning circulation and heat transport

of the global combined atmosphere-ocean heat flux and so is important for the mean climate of the Atlantic sector of the Northern Hemisphere. This meridional heat flux is accomplished by both the Atlantic Meridional Overturning Circulation (AMOC) and by basin-wide horizontal gyre circulations. In the North Atlantic subtropical latitudes the AMOC dominates the meridional heat flux, while in subpolar latitudes and in the subtropical South Atlantic the gyre circulations are also important. Climate models suggest the AMOC will slow over the coming decades as the earth warms, causing widespread cooling in the Northern hemisphere and additional sea-level rise. Monitoring systems for selected components of the AMOC have been in place in some areas for decades, nevertheless the present observational network provides only a partial view of the AMOC, and does not unambiguously resolve the full variability of the circulation. Additional observations, building on existing measurements, are required to more completely quantify the Atlantic meridional heat transport. A basin-wide monitoring array along 26.5°N has been continuously measuring the strength and vertical structure of the AMOC and meridional heat transport since March 31, 2004. The array has demonstrated its ability to observe the AMOC variability at that latitude and also a variety of surprising variability that will require substantially longer time series to understand fully. Here we propose monitoring the Atlantic meridional heat transport throughout the Atlantic at selected critical latitudes that have already been identified as regions of interest for the study of deep water formation and the strength of the subpolar gyre, transport variability of the Deep Western Boundary Current (DWBC) as well as the upper limb of the AMOC, and inter-ocean and intrabasin exchanges with the ultimate goal of determining regional and global controls for the AMOC in the North and South Atlantic Oceans. These new arrays will continuously measure the full depth, basin-wide or choke-point circulation and heat transport at a number of latitudes, to establish the dynamics and variability at each latitude and then their meridional connectivity. Modeling studies indicate that adaptations of the 26.5°N type of array may provide successful AMOC monitoring at other latitudes. However, further analysis and the development of new technologies will be needed to optimize cost effective systems for providing long term monitoring and data recovery at climate time scales. These arrays will provide benchmark observations of the AMOC that are fundamental for assimilation, initialization, and the verification of coupled hindcast/forecast climate models

Energiebesparing mobiele belichting roos

Over mobiele belichting wordt al jarenlang op verschillende manieren gedacht: enerzijds zou het een manier zijn om lage lichtintensiteiten goed te verdelen over het gewas, anderzijds zou het een manier zijn om energie te besparen, doordat met minder lampen hetzelfde groei-effect werd verwacht. De ‘bewijzen’ van meerproductie onder mobiel licht, vergeleken met dezelfde of een hogere lichtsom waren alleen afkomstig uit praktijkproeven. Een echte fysiologische verklaring voor de vermeende effecten van mobiel licht is nooit gegeven en getoetst. Eén van de theorieën veronderstelt een beter gebruik van het licht (daglicht én assimilatielicht) doordat er af en toe een lichtpuls van hogere intensiteit de planten raakt. Ook zou het op gang komen van de fotosynthese tijdens de lichtpuls beter zijn dan bij continue belichting, zodat wanneer het daglicht fluctueert, de fotosynthese sneller op gang komt in de lichte perioden. Een eventuele betere regulatie van de opening van de huidmondjes (waar de CO2 door naar binnen moet) is ook genoemd. Om te bepalen of er positieven effecten van mobiele belichting zijn en of ze te verklaren zijn uit de eigenschappen van de fotosynthese is een proef met roos uitgevoerd. In deze proef is gekozen voor de zogenaamde ‘lange slag’ mobiele belichting. Dat wil zeggen dat de lampen een lange weg afleggen boven het gewas (in dit project ca 10 meter) en dat de lichtintensiteit tussen twee lichtpulsen in heel laag of nihil is. Ook is er geen achtergrondbelichting van vaste assimilatiebelichting bij de mobiele belichting. De lichtintensiteit voor de planten onder mobiele lampen varieert ‘s nachts daardoor van heel hoog tot nul. In de rozenpraktijk wordt ondertussen vooral belicht met ‘korte slag’ belichting, waar de weg van de lampen meestal van poot tot poot is, dus 4 à 5 meter, en waarbij er wél achtergrondbelichting is van vaste lampen. Deze planten ondervinden dus wel een wisselende lichtintensiteit, maar ‘s nachts wordt de lichtintensiteit nooit nul. Te verwachten is dat de fysiologische verschillen tussen mobiele en vaste belichting bij een lange-slag belichting groter zijn dan bij een korte-slag belichting

Tomaten belichten met minder elektriciteit

Over the last 10 years, the use of electricity for assimilation lighting has increased considerably. It is now an important part of the energy use of the horticultural sector. To reverse this trend, in the lighting season 2013/2014, we conducted a trial with the aim to reduce the electricity use in a lighted tomato crop by 35% while maintaining production levels. Two treatments were applied: (1) Reference cultivation: clear glass and lighting by 50% HPS lamps and 50% LED intermittent lighting (210 µmol/m2/s), (2) energy efficient cultivation: diffuse greenhouse cover and lighting by 50% LED top lighting and 50% intermittent LED lighting (210 µmol/m2/s). In the energy efficient cultivation, 37% less electricity was used in the period October - May. However, energy use for heating in this treatment was higher to compensate for the lack of radiative heat. The light sum the plants received (sunlight + artificial lighting) was 6% lower in the energy efficient cultivation compared to the reference cultivation due to the lower number of lighting hours. However, the production difference was only 0.3 kg/m2, less than 1%! Detailed plant measurements showed hardly any differences between the treatments in light interception, light absorption by the leaves, photosynthesis and the production and distribution of assimilates. The analysis of the crop growth model showed that the effect of the lower number of lighting hours in the energy efficient cultivation was fully compensated by the positive effects of the diffuse greenhouse cover which has a higher light transmission

Ocean impact on decadal Atlantic climate variability revealed by sea-level observations

Decadal variability is a notable feature of the Atlantic Ocean and the climate of the regions it influences. Prominently, this is manifested in the Atlantic Multidecadal Oscillation (AMO) in sea surface temperatures. Positive (negative) phases of the AMO coincide with warmer (colder) North Atlantic sea surface temperatures. The AMO is linked with decadal climate fluctuations, such as Indian and Sahel rainfall1, European summer precipitation2, Atlantic hurricanes3 and variations in global temperatures4. It is widely believed that ocean circulation drives the phase changes of the AMO by controlling ocean heat content5. However, there are no direct observations of ocean circulation of sufficient length to support this, leading to questions about whether the AMO is controlled from another source6. Here we provide observational evidence of the widely hypothesized link between ocean circulation and the AMO. We take a new approach, using sea level along the east coast of the United States to estimate ocean circulation on decadal timescales. We show that ocean circulation responds to the first mode of Atlantic atmospheric forcing, the North Atlantic Oscillation, through circulation changes between the subtropical and subpolar gyres—the intergyre region7. These circulation changes affect the decadal evolution of North Atlantic heat content and, consequently, the phases of the AMO. The Atlantic overturning circulation is declining8 and the AMO is moving to a negative phase. This may offer a brief respite from the persistent rise of global temperatures4, but in the coupled system we describe, there are compensating effects. In this case, the negative AMO is associated with a continued acceleration of sea-level rise along the northeast coast of the United States9, 10