Proyecto MeCIN: Alto Valle de Río Negro, Argentina

this paper presents the results of field experience mecin (measurements of the nocturnal inversion layer). the project was performed to study the characteristics of wind, air temperature and the evolution of nocturnal cooling in the neuquén, limay, and negro river valleys during nighttime with thermal inversion in the layer near ground, between 1992 and 1997 spring seasons. the mean synoptic situations that favored the nocturnal radiative effects were associated with migratory postfrontal 1000 hpa anticyclones and a though axis in 500 hpa. the mean vertical gradient of air temperature was 0,26 °c/m in the neuquén river valley and 0,14 °c/m in the negro river valley. the top of the thermal inversion, on the average, was located above 30 m. the wind speed profile presented two layers: a lower one with calm and an upper layer with mean wind speed between 2,9 m/s and 4,0 m/s. the cooling of air during night was greater in the zone of small farms and smaller in the neighborhood of the river and on the plateau. the nighttime air temperature was smaller in the valley that in the plateau, and varied with height.