The end of the last interglacial period, ~118 kyr ago, was characterized by substantial ocean circulation and climate perturbations resulting from instabilities of polar ice sheets. These perturbations are crucial for a better understanding of future climate change. The seasonal temperature changes of the tropical ocean, however, which play an important role in seasonal climate extremes such as...

We used 5704 14C, 10Be, and 3He ages that span the interval from 10,000 to 50,000 years ago (10 to 50 ka) to constrain the timing of the Last Glacial Maximum (LGM) in terms of global ice-sheet and mountain-glacier extent. Growth of the ice sheets to their maximum positions occurred between 33.0 and 26.5 ka in response to climate forcing from decreases in northern summer insolation, tropical Pac...

[1] The last glacial inception ( 116 ky ago) has long been used to test the sensitivity of climate models to insolation. From these simulations, atmospheric, oceanic and vegetation feedbacks have been shown to amplify the initial insolation signal into a rapid growth of ice-sheets over the northern hemisphere. However, due to the lack of comprehensive atmosphere-ocean-vegetation-northern hemisp...

Holocene variations of tropical moisture balance have been ascribed to orbitally forced changes in solar insolation. If this model is correct, millennial-scale climate evolution should be antiphased between the northern and southern hemispheres, producing humid intervals in one hemisphere matched to aridity in the other. Here we show that Holocene climate trends were largely synchronous and in ...

This paper introduces a new tool for analysing annual solar insolation potentials for façades and roofs at an urban scale using Trimble SketchUp and the dynamic simulation model HTB2. The tool is in the form of a plugin which 1) generates shading masks for every façade and roof in a model, 2) exports geometries to HTB2 for analysis, 3) invokes HTB2 from within SketchUp, and 4) returns outputs i...

In a conceptual model of global atmospheric circulation, the effects of annually periodic driving are investigated. The driven system is represented in terms of snapshot attractors, which may remain fractal at all times. This is due to the transiently chaotic behavior in the regular parameter regimes of the undriven system. The driving with annual periodicity is found to be relatively fast: The...

During the last deglaciation, wetter conditions developed abruptly ~14,700 years ago in southeastern equatorial and northern Africa and continued into the Holocene. Explaining the abrupt onset and hemispheric coherence of this early African Humid Period is challenging due to opposing seasonal insolation patterns. In this work, we use a transient simulation with a climate model that provides a m...

C, Ca Filter, array capacitance d1, d2 Duty ratios of switch S1,S2 DP1, DP2 Diodes of individual boost cells IA SCA current IAb SCA current with boost converter IAd SCA current with IDB converter Im SCA current at maximum power operation Iab Average load current with boost converter Iaid Average load current with IDB converter Iph Insolation dependent photo current I0 Cell reverse saturation cu...

The performance of solar photovoltaic (PV) array is affected in conditions like Array tilt (optimum = latitude), Array tracking (1-axis, 2axis), Array azimuth/orientation (optimum = 180o or South), Array temperature, Array “soiling” (dust/dirt, snow, foreign matter etc.), Array shading (trees, clouds, buildings, chimneys, dormers, utility and telephone poles etc.), Array configuration, Array ag...

[1] Global upper ocean evolution in the Holocene is studied in two coupled ocean-atmosphere models under orbital forcing conditions at 3, 6, 8, and 11 ka. The annual mean sea surface temperature (SST) changes in the early to mid-Holocene are found to be forced mainly by the annual mean insolation forcing with an overall symmetric response of colder equator (<0.5 C)/warmer high latitudes (<0.4 C...