Solar and thermal radiative effects during the 2011 extreme desert dust episode over Portugal

This paper analyses the influence of the extreme Saharan desert dust (DD) event on shortwave (SW) and longwave (LW) radiation at the EARLINET/AERONET Évora station (Southern Portugal) from 4 up to 7 April 2011. There was also some cloud occurrence in the period. In this context, it is essential to quantify the effect of cloud presence on aerosol radiative forcing. A radiative transfer model was initialized with aerosol optical properties, cloud vertical properties and meteorological atmospheric vertical profiles. The intercomparison between the instantaneous TOA shortwave and longwave fluxes derived using CERES and those calculated using SBDART, which was fed with aerosol extinction coefficients derived from the CALIPSO and lidar-PAOLI observations, varying OPAC dataset parameters, was reasonably acceptable within the standard deviations. The dust aerosol type that yields the best fit was found to be the mineral accumulation mode. Therefore, SBDART model constrained with the CERES observations can be used to reliably determine aerosol radiative forcing and heating rates. Aerosol radiative forcings and heating rates were derived in the SW (ARFSw, AHRSw) and LW (ARFLw, AHRLw) spectral ranges, considering a cloud-aerosol free reference atmosphere. We found that AOD at 440 nm increased by a factor of 5 on 6 April with respect to the lower dust load on 4 April. It was responsible by a strong cooling radiative effect pointed out by the ARFSw value (−99 W/m2 for a solar zenith angle of 60°) offset by a warming radiative effect according to ARFLw value (+21.9 W/m2) at the surface. Overall, about 24% and 12% of the dust solar radiative cooling effect is compensated by its longwave warming effect at the surface and at the top of the atmosphere, respectively. Hence, larger aerosol loads could enhance the response between the absorption and re-emission processes increasing the ARFLw with respect to those associated with moderate and low aerosol loads. The unprecedented results derived from this work complement the findings in other regions on the modifications of radiative energy budget by the dust aerosols, which could have relevant influences on the regional climate and will be topics for future investigations.

Territorialisation and power in Portuguese America. The creation of comarcas (16th-18th centuries)

The general aim of this article is to analyse the political organisation of the territory in Portuguese America from the start of the building up of the Crown judiciary system from in the 16th to the 18th centuries and to look into the causes of its belatedness in comparison to what happened in Spanish America. The focus will however be on the comarcas through the reconstitution of the process leading to the setting up of these judiciary divisions. Four stages of this process will be identified and discussion will ensue over the social and political contexts in which these political and administrative novelties came to happen. It is claimed that the delay in the structuring of the judicial network in the States of Brazil and Maranhão stems from the fact that the Portuguese advance into the territories took place at a later stage. The comparisons between the two systems will also bring other differences to the fore, not least the greater rigidity of the Spanish model in contrast to the more experimental character of the Portuguese one, and the resilience found to exist in the donatarial system. It is also worth to point out that given solutions were the result of the will of central power as much as of local initiative, and it is suggested that the building up of the crown’s political apparatus (in which the judiciary network is included) brought about the connivance,albeit ephemeral, of social interests which are considered contradictory or irreconcilable by some authors.

Early Modern Trading Networks in Europe. Cooperation and the case of Simon Ruiz.

In the early modern period, trade became a truly global phenomenon. The logistics, financial and organizational complexity associated with it increased in order to connect distant geographies and merchants from different backgrounds. How did these merchants prevent their partners from dishonesty in a time where formal institutions and legislation did not traverse these different worlds? This book studies the mechanisms and criteria of cooperation in early modern trading networks. It uses an interdisciplinary approach, through the case study of a Castilian long-distance merchant of the sixteenth century, Simon Ruiz, who traded within the limits of the Portuguese and Spanish overseas empires. Early Modern Trading Networks in Europe discusses the importance of reciprocity mechanisms, trust and reputation in the context of early modern business relations, using network analysis methodology, combining quantitative data with qualitative information. It considers how cooperation and prevention could simultaneously create a business relationship, and describes the mechanisms of control, policing and punishment used to avoid opportunism and deception among a group of business partners. Using bills of exchange and correspondence from Simon Ruiz’s private archive, it charts the evolution of this business network through time, debating which criteria should be included or excluded from business networks, as well as the emergence of standards. This book intends to put forward a new approach to early modern trade which focuses on individuals interacting in self-organized structures, rather than on states or empires. It shows how indirect reciprocity was much more frequent than direct reciprocity among early modern merchants and how informal norms, like ostracism or signaling, helped to prevent defection and deception in an effective way.