Research Article The Influence of the Intermittent Behavior of the Nocturnal Atmospheric Flow on the Prediction of the Diurnal Temperature Range: A Simplified Model Analysis Leandro L. Gonzales, 1,2 Felipe D. Costa, 2 Otávio C. Acevedo, 3 Daniel M. dos Santos, 2 Luiz E. Medeiros, 2 Arlindo D. Carvalho Junior, 2 Franciano S. Puhales, 3 Vagner Anabor, 3 Luis G. N. Martins, 3 Giuliano Demarco, 4 and Gervásio A. Degrazia 3 1 Instituto Federal Sul-Rio-Grandense, Campus Pelotas, Pelotas, RS, Brazil 2 Programa de P´ os-Graduac ¸˜ ao em Engenharia, Universidade Federal do Pampa, Campus Alegrete, Alegrete, RS, Brazil 3 Departamento de F´ ısica, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil 4 Departamento de Engenharia Mecˆ anica, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil Correspondence should be addressed to Felipe D. Costa; fdenardin@unipampa.edu.br Received 1 February 2017; Revised 17 April 2017; Accepted 2 May 2017; Published 8 June 2017 Academic Editor: Enrico Ferrero Copyright © 2017 Leandro L. Gonzales et al. Tis is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Te variation of the atmospheric temperature near the surface associated with anthropogenic efects is analyzed using a simplifed atmospheric model. Local changes in cloud cover and four diferent scenarios of atmospheric concentration of carbon dioxide are considered. Te results show that the highest temperature variability occurs in the weak wind and decoupled state and in the transition between fow regimes. In agreement with previous eforts, the results indicate that the reduction of diurnal temperature range is related to the existence of two distinct fow regimes in the stable boundary layer. However, in the decoupled state, the occurrence of intermittent bursts of turbulence may cause temperature variations among the diferent scenarios to become unpredictable. It implies that it is difcult to predict the diurnal temperature range in places where low winds are common. 1. Introduction Te increase of the concentration of greenhouse gases, such as methane and CO 2 , in the atmosphere, has been causing anomalous elevations in the temperature in the last two centuries [1]. Furthermore, the temperature elevation is not homogenous throughout the diurnal cycle. It has been sug- gested that the daily minimum temperatures may have risen twice as fast as the corresponding maxima since 1950 [2, 3]. Tose observations, however, are not generally reproduced by atmospheric models [4, 5]. Reference [4] observed that doubling the concentration of the carbon dioxide was not enough to signifcantly afect the diurnal temperature range (DTR). Reference [5] found similar results and suggested that the problem resides in the turbulence boundary layer schemes that are used in the atmospheric models, mainly because of their bad performance during nighttime. In this period, the only source of turbulence is the wind shear, as the stable stratifcation causes buoyant forces to destroy turbulence. Te relative magnitude of those two terms from the turbulent kinetic energy budget equation ultimately leads to two distinct regimes in stable boundary layer (SBL) [6–9]. A decoupled regime is characterized by light winds and weak turbulence that can alternate with periods with more intense turbulence, in a phenomena known as global intermittency, or just intermittency [6]. On the other hand, the coupled state happens for moderate to strong winds, and the turbulence is always well developed and self-sustained [10]. During the same night, the fow can switch regimes, and those changes can occur intermittently or in an organized way and can lead to temperature variability as large as 10 K [11]. Recent studies [8–10] have identifed that to a large extent the SBL regime is solely determined by mean wind speed. Anyhow, atmospheric models do not usually represent well Hindawi Advances in Meteorology Volume 2017, Article ID 1432672, 8 pages https://doi.org/10.1155/2017/1432672