1,041 research outputs found
The AWI Network Antarctica - Alfred-Wegener Institute, Germany
Tanja Fromm, Alfons Eckstaller and Jölund Asseng report on the AWI network in Antarctica for the Summary of the Bulletin of the International Seismological Centre
Towards a self-sufficient mobile broadband seismological recording system for year-round operation in Antarctica
Passive seismic measurements allow the study of the deeper Earth beneath the thick Antarctic ice sheet cover. Due to logistical and weather constraints, only a fraction of the area of the Antarctic ice sheet can be surveyed with long-term or temporary sensors. A fundamental limitation is the power supply and operation of the instruments during the polar winter. In addition, there is only a limited time window during the field seasons to deploy the stations over the year. Here we present a rapidly and simple deployable self-sufficient mobile seismic station concept. The station consists of different energy supply modules aligned according to the survey needs, measuring duration, and survey aim. Parts of the concept are integrated into an already existing pool of mobile stations and in the seismological network of the geophysical observatory at Neumayer III Station. Other concepts and features are still under development. The overall goal is to use these temporary mobile arrays in regions where little is known about local and regional tectonic earthquake activity
Optimal Control for Indoor Vertical Farms Based on Crop Growth
Vertical farming allows for year-round cultivation of a variety of crops,
overcoming environmental limitations and ensuring food security. This closed
and highly controlled system allows the plants to grow in optimal conditions,
so that they reach maturity faster and yield more than on a conventional
outdoor farm. However, one of the challenges of vertical farming is the high
energy consumption. In this work, we optimize wheat growth using an optimal
control approach with two objectives: first, we optimize inputs such as water,
radiation, and temperature for each day of the growth cycle, and second, we
optimize the duration of the plant's growth period to achieve the highest
possible yield over a whole year. For this, we use a nonlinear, discrete-time
hybrid model based on a simple universal crop model that we adapt to make the
optimization more efficient. Using our approach, we find an optimal trade-off
between used resources, net profit of the yield, and duration of a cropping
period, thus increasing the annual yield of crops significantly while keeping
input costs as low as possible. This work demonstrates the high potential of
control theory in the discipline of vertical farming.Comment: This work has been accepted for presentation at IFAC World Congress
202
Influences of increasing temperature on Indian wheat: quantifying limits to predictability
As climate changes, temperatures will play an increasing role in determining crop yield. Both
climate model error and lack of constrained physiological thresholds limit the predictability of
yield. We used a perturbed-parameter climate model ensemble with two methods of
bias-correction as input to a regional-scale wheat simulation model over India to examine
future yields. This model configuration accounted for uncertainty in climate, planting date,
optimization, temperature-induced changes in development rate and reproduction. It also
accounts for lethal temperatures, which have been somewhat neglected to date. Using
uncertainty decomposition, we found that fractional uncertainty due to temperature-driven
processes in the crop model was on average larger than climate model uncertainty (0.56 versus
0.44), and that the crop model uncertainty is dominated by crop development. Simulations
with the raw compared to the bias-corrected climate data did not agree on the impact on future
wheat yield, nor its geographical distribution. However the method of bias-correction was not
an important source of uncertainty. We conclude that bias-correction of climate model data
and improved constraints on especially crop development are critical for robust impact
predictions
The role of Antarctic overwintering teams and their significance for German polar research
Germany has been operating permanently crewed research stations in Antarctica for more than 45 years. The opening of the Georg Forster Station (1976) and Georg von Neumayer Station (1981) initiated a period of continuous environmental monitoring that allowed both the former East Germany and West Germany to become contracting parties in, and achieve consultative status with, the framework of the Antarctic Treaty. This marked a milestone in German polar research. Continuous research at the Neumayer Station III, its two predecessors, and the now-dismantled former German Democratic Republic (GDR) Georg Forster Station is undertaken by teams of so-called "overwinterers", presently with nine members, who stay at the base for longer than an entire Antarctic winter. Their long-Term stay in Antarctica is defined by isolation, separation from civilization, routine work to sustain long-Term scientific observations, and unique personal experiences. This article is dedicated to them and outlines their part and role in the German Antarctic research landscape
The role of Antarctic overwintering teams and their significance for German polar research
Germany has been operating permanently crewed research stations in Antarctica for more than 45 years. The opening of the Georg Forster Station (1976) and Georg von Neumayer Station (1981) initiated a period of continuous environmental monitoring that allowed both the former East Germany and West Germany to become contracting parties in, and achieve consultative status with, the framework of the Antarctic Treaty. This marked a milestone in German polar research. Continuous research at the Neumayer Station III, its two predecessors, and the now-dismantled former German Democratic Republic (GDR) Georg Forster Station is undertaken by teams of so-called “overwinterers”, presently with nine members, who stay at the base for longer than an entire Antarctic winter. Their long-term stay in Antarctica is defined by isolation, separation from civilization, routine work to sustain long-term scientific observations, and unique personal experiences. This article is dedicated to them and outlines their part and role in the German Antarctic research landscape
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