ANÁLISE DOS PARÂMETROS PARA GERAÇÃO DE ENERGIA SOLAR FOTOVOLTAICA NO ACRE, BRASIL

ANALYSIS OF PARAMETERS FOR PHOTOVOLTAIC SOLAR ENERGY GENERATION IN ACRE, BRAZILANÁLISIS DE PARÁMETROS PARA LA GENERACIÓN DE ENERGÍA SOLAR FOTOVOLTAICA EN ACRE, BRASILRESUMOEnergia solar é obtida através de placas solares fotovoltaicas com a função de captar a energia do sol e transformar em energia elétrica, aumentando a geração de energia solar nas regiões com maior captação de energia luminosa. Assim, neste artigo analisou-se os parâmetros para geração de energia solar fotovoltaica no Acre, Brasil. Coletou-se dados referentes a insolação, temperaturas máximas e mínimas, precipitação e umidade relativa no Instituto Nacional de Meteorologia, irradiação solar, no Centro de Referências para Energias Solar e Eólica Sérgio de S. Brito, regionais do Vale do Juruá e Vale do Acre, no período de 2015-2020. As análises foram quantitativas, utilizando o cálculo da média e cálculo do plano inclinado. Na comparação das regionais, o Vale do Acre apresentou melhores resultados para geração de energia solar e com um ângulo com a maior média diária anual de irradiação solar, considerando-se projetar-se células fotovoltaicas na regional. O trabalho apresenta que o Acre possui bastante insolação e irradiação solar, indicando alto potencial de geração de energia solar para as regionais do estado.Palavras-chave: Eficiência Fotovoltaica; Radiação Solar; Temperatura da Célula Fotovoltaica; Irradiação.ABSTRACTSolar energy is obtained through photovoltaic solar panels with the function of capturing the sun's energy and transforming it into electrical energy, increasing the generation of solar energy in regions with greater capture of light energy. Thus, the parameters for the generation of photovoltaic solar energy in Acre, Brazil were analyzed. Data on insolation, maximum and minimum temperatures, precipitation and relative humidity were collected at the National Institute of Meteorology, solar irradiation, at the Reference Center for Solar and Wind Energy Sérgio de S. Brito, regions of Vale do Juruá and Vale do Acre, in the period 2015-2020. Analyzes were quantitative, using mean calculation and inclined plane calculation. When comparing the regions, Vale do Acre presented better results for solar energy generation and with an angle with the highest annual daily average of solar irradiation, considering the project of photovoltaic cells in the region. The work shows that Acre has a lot of insolation and solar irradiation, indicating a high potential for generating solar energy for the regional regions of the state.Keywords: Photovoltaic Efficiency; Solar Radiation; Photovoltaic Cell Temperature; Irradiation.RESUMENLa energía solar se obtiene a través de paneles solares fotovoltaicos con la función de captar la energía del sol y transformarla en energía eléctrica, aumentando la generación de energía solar en las regiones con mayor captación de energía luminosa. Así, se analizaron los parámetros para la generación de energía solar fotovoltaica en Acre, Brasil. Los datos sobre insolación, temperaturas máximas y mínimas, precipitación y humedad relativa fueron recolectados en el Instituto Nacional de Meteorología, irradiación solar, en el Centro de Referencia de Energía Solar y Eólica Sérgio de S. Brito, regiones de Vale do Juruá y Vale do Acre, en el período 2015-2020. Los análisis fueron cuantitativos, utilizando cálculo de medias y cálculo de plano inclinado. Al comparar las regiones, Vale do Acre presentó mejores resultados para la generación de energía solar y con un ángulo con el promedio diario anual más alto de irradiación solar, considerando el diseño de células fotovoltaicas en la región. El trabajo muestra que Acre tiene mucha insolación e irradiación solar, lo que indica un alto potencial de generación de energía solar para las regiones regionales del estado.Palabras clave: Eficiencia Fotovoltaica; Radiación Solar; Temperatura de la Celda Fotovoltaica; Irradiación.

Pacific warm pool subsurface heat sequestration modulated Walker circulation and ENSO activity during the Holocene

Dynamics driving the El Niño–Southern Oscillation (ENSO) over longer-than-interannual time scales are poorly understood. Here, we compile thermocline temperature records of the Indo-Pacific warm pool over the past 25,000 years, which reveal a major warming in the Early Holocene and a secondary warming in the Middle Holocene. We suggest that the first thermocline warming corresponds to heat transport of southern Pacific shallow overturning circulation driven by June (austral winter) insolation maximum. The second thermocline warming follows equatorial September insolation maximum, which may have caused a steeper west-east upper-ocean thermal gradient and an intensified Walker circulation in the equatorial Pacific. We propose that the warm pool thermocline warming ultimately reduced the interannual ENSO activity in the Early to Middle Holocene. Thus, a substantially increased oceanic heat content of the warm pool, acting as a negative feedback for ENSO in the past, may play its role in the ongoing global warming.

Decadal resolution record of Oman margin upwelling indicates persistent solar forcing of the Indian summer monsoon after the early Holocene summer insolation maximum

The Indian summer monsoon (ISM) brings most of the annual precipitation to the densely populated region in southern Asia. For the agricultural development and economic prosperity of the region, it is therefore vital to assess the variability of the monsoon system on societal relevant decadal- to centennial time scales. This might help to better understand how potential driving forces might be controlling ISM variability and how it might develop under future climate scenarios. Here we present a study of a sediment core from the northern Oman margin, revealing early- to mid Holocene ISM conditions on a near 20-year resolution. We assess multiple independent proxies indicative of sea surface temperatures (SST) during the upwelling season together with bottom water conditions. We use geochemical parameters, transfer functions of planktic foraminiferal assemblages and Mg/Ca paleothermometry and find evidence corroborating previous studies that upwelling intensity varies significantly in coherence to solar sunspot cycles. The dominant ~80–90-year Gleissberg cycle was apparently also affecting bottom water oxygen conditions. Although the interval from 8.4 to 5.8 ka B.P. is relatively short, the gradually decreasing trend of summer monsoon conditions was interrupted by short events of intensified ISM conditions. Results from both independent SST proxies are linked to phases of weaker OMZ conditions and enhanced carbonate preservation. This indicates that atmospheric forcing was intimately linked to bottom water properties and state of the OMZ on decadal time scales.

Simulating last interglacial climate with NorESM: role of insolation and greenhouse gases in the timing of peak warmth

The last interglacial (LIG) is characterized by high latitude warming and is therefore often considered as a possible analogue for future warming. However, in contrast to predicted future greenhouse warming, the last interglacial climate is largely governed by variations in insolation. Greenhouse gas (GHG) concentrations were relatively stable and similar to pre-industrial values, with the exception of the early last interglacial where GHGs were slightly lower. We performed six time-slice simulations with the low resolution version of the Norwegian Earth System Model covering the last interglacial. In four simulations only orbital forcing was changed, and in two simulations additionally GHG forcing was reduced to values appropriate for the early last interglacial. Our simulations show that insolation forcing results in seasonal and hemispheric differences in temperature. In contrast, a reduction in greenhouse gas forcing causes a global and seasonal-independent cooling. We also compare our modelled results to proxy data extracted from four marine sediment cores covering the entire last interglacial along a northeast-southwest transect in the North Atlantic. Our modelled North Atlantic summer sea surface temperatures capture the general trend of the proxy summer temperatures, with low values in the early last interglacial, a peak around 125 ka, and a steady decrease towards the end of the last interglacial. Temperatures computed by the simulations with reduced GHG forcing improve the fit as they show lower temperatures in the early last interglacial. Furthermore we show that the timing of maximum surface temperatures follows the local insolation maximum. Two exceptions are the temperatures on Antarctica that show maxima at both ~ 130 ka and ~ 115 ka, and the Southern Ocean austral summer temperatures that peak early at ~ 130 ka. This is probably due to the integrating effect of the ocean, storing summer heat and resulting in relatively warm winter temperatures.

Can we predict the duration of an interglacial?

Differences in the duration of interglacials have long been apparent in palaeoclimate records of the Late and Middle Pleistocene. However, a systematic evaluation of such differences has been hampered by the lack of a metric that can be applied consistently through time and by difficulties in separating the local from the global component in various proxies. This, in turn, means that a theoretical framework with predictive power for interglacial duration has remained elusive. Here we propose that the interval between the terminal oscillation of the bipolar seesaw and three thousand years (kyr) before its first major reactivation provides an estimate that approximates the length of the sea-level highstand, a measure of interglacial duration. We apply this concept to interglacials of the last 800 kyr by using a recently-constructed record of interhemispheric variability. The onset of interglacials occurs within 2 kyr of the boreal summer insolation maximum/precession minimum and is consistent with the canonical view of Milankovitch forcing pacing the broad timing of interglacials. Glacial inception always takes place when obliquity is decreasing and never after the obliquity minimum. The phasing of precession and obliquity appears to influence the persistence of interglacial conditions over one or two insolation peaks, leading to shorter (~ 13 kyr) and longer (~ 28 kyr) interglacials. Glacial inception occurs approximately 10 kyr after peak interglacial conditions in temperature and CO2, representing a characteristic timescale of interglacial decline. Second-order differences in duration may be a function of stochasticity in the climate system, or small variations in background climate state and the magnitude of feedbacks and mechanisms contributing to glacial inception, and as such, difficult to predict. On the other hand, the broad duration of an interglacial may be determined by the phasing of astronomical parameters and the history of insolation, rather than the instantaneous forcing strength at inception.

Holocene palaeohydrological changes in the northern Mediterranean borderlands as reflected by the lake-level record of lake ledro, northeastern Italy

A lake-level record of Lake Ledro (northern Italy) spans the entire Holocene with a chronology derived from 51 radiocarbon dates. It is based on a specific sedimentological approach that combines data from five sediment profiles sampled in distinct locations in the littoral zone. On a millennial scale, the lake-level record shows two successive periods from 11,700 to 4500 cal yr BP and from 4500 cal yr BP to the present, characterized by lower and higher average lake levels, respectively. In addition to key seasonal and inter-hemispherical changes in insolation, the major hydrological change around 4500 cal yr BP may be related to a non-linear response of the climate system to orbitally-driven gradual decrease in insolation. The Ledro record questions the notion of an accentuated summer rain regime in the northern Mediterranean borderlands during the boreal insolation maximum. Moreover, the Ledro record highlights that the Holocene was punctuated by successive centennial-scale highstands. Correlations with the Preboreal oscillation and the 8.2 ka event, and comparison with the atmospheric 14C residual record, suggest that short-lived lake-level fluctuations developed at Ledro in response to (1) final steps of the deglaciation in the North Atlantic area and (2) variations in solar activity.

Corrigendum to "Upper ocean climate of the Eastern Mediterranean Sea during the Holocene Insolation Maximum – a model study" published in Clim. Past, 7, 1103–1122, 2011

Nine thousand years ago (9 ka BP), the Northern Hemisphere experienced enhanced seasonality caused by an orbital configuration close to the minimum of the precession index. To assess the impact of this "Holocene Insolation Maximum" (HIM) on the Mediterranean Sea, we use a regional ocean general circulation model forced by atmospheric input derived from global simulations. A stronger seasonal cycle is simulated by the model, which shows a relatively homogeneous winter cooling and a summer warming with well-defined spatial patterns, in particular, a subsurface warming in the Cretan and western Levantine areas. The comparison between the SST simulated for the HIM and a reconstruction from planktonic foraminifera transfer functions shows a poor agreement, especially for summer, when the vertical temperature gradient is strong. As a novel approach, we propose a reinterpretation of the reconstruction, to consider the conditions throughout the upper water column rather than at a single depth. We claim that such a depth-integrated approach is more adequate for surface temperature comparison purposes in a situation where the upper ocean structure in the past was different from the present-day. In this case, the depth-integrated interpretation of the proxy data strongly improves the agreement between modelled and reconstructed temperature signal with the subsurface summer warming being recorded by both model and proxies, with a small shift to the south in the model results. The mechanisms responsible for the peculiar subsurface pattern are found to be a combination of enhanced downwelling and wind mixing due to strengthened Etesian winds, and enhanced thermal forcing due to the stronger summer insolation in the Northern Hemisphere. Together, these processes induce a stronger heat transfer from the surface to the subsurface during late summer in the western Levantine; this leads to an enhanced heat piracy in this region, a process never identified before, but potentially characteristic of time slices with enhanced insolation.

Upper ocean climate of the Eastern Mediterranean Sea during the Holocene Insolation Maximum – a model study

Nine thousand years ago (9 ka BP), the Northern Hemisphere experienced enhanced seasonality caused by an orbital configuration close to the minimum of the precession index. To assess the impact of this "Holocene Insolation Maximum" (HIM) on the Mediterranean Sea, we use a regional ocean general circulation model forced by atmospheric input derived from global simulations. A stronger seasonal cycle is simulated by the model, which shows a relatively homogeneous winter cooling and a summer warming with well-defined spatial patterns, in particular, a subsurface warming in the Cretan and western Levantine areas. The comparison between the SST simulated for the HIM and a reconstruction from planktonic foraminifera transfer functions shows a poor agreement, especially for summer, when the vertical temperature gradient is strong. As a novel approach, we propose a reinterpretation of the reconstruction, to consider the conditions throughout the upper water column rather than at a single depth. We claim that such a depth-integrated approach is more adequate for surface temperature comparison purposes in a situation where the upper ocean structure in the past was different from the present-day. In this case, the depth-integrated interpretation of the proxy data strongly improves the agreement between modelled and reconstructed temperature signal with the subsurface summer warming being recorded by both model and proxies, with a small shift to the south in the model results. The mechanisms responsible for the peculiar subsurface pattern are found to be a combination of enhanced downwelling and wind mixing due to strengthened Etesian winds, and enhanced thermal forcing due to the stronger summer insolation in the Northern Hemisphere. Together, these processes induce a stronger heat transfer from the surface to the subsurface during late summer in the western Levantine; this leads to an enhanced heat piracy in this region, a process never identified before, but potentially characteristic of time slices with enhanced insolation.

Holocene evolution of summer winds and marine productivity in the tropical Indian Ocean in response to insolation forcing: data-model comparison

The relative abundance of Globigerinoides bulloides was used to infer Holocene paleo-productivity changes on the Oman margin and at the southern tip of India. Today, the primary productivity at both sites reaches its maximum during the summer season, when monsoon winds result in local Eckman pumping, which brings more nutrients to the surface. On a millennium time-scale, however, the % G. bulloides records indicate an opposite evolution of paleo-productivity at these sites through the Holocene. The Oman Margin productivity was maximal at ~9 ka (boreal summer insolation maximum) and has decreased since then, suggesting a direct response to insolation forcing. On the contrary, the productivity at the southern tip of India was minimum at ~9 ka, and strengthened towards the present. Paleo-reconstructions of wind patterns, marine productivity and foraminifera assemblages were obtained using the IPSL-CM4 climate model coupled to the PISCES marine biogeochemical model and the FORAMCLIM ecophysiological model. These reconstructions are fully coherent with the marine core data. They confirm that the evolution of particulate export production and foraminifera assemblages at our two sites were directly linked with the strength of the upwelling. Model simulations at 9 ka and 6 ka BP show that the relative evolution between the two sites since the early Holocene can be explained by the weakening but also the southward shift of monsoon winds over the Arabian Sea during boreal summer.