Recent observations of z ∼ 6 quasars and the cosmic microwave background imply a complex history to cosmic reionization. Such a history requires some form of feedback to extend reionization over a long time interval, but the nature of the feedback and how rapidly it operates remain highly uncertain. Here we focus on one aspect of this complexity: which physical processes can cause the global io...

Although numerical models are essential to hurricane forecasting, many other applications require only statistical depiction of the wind distribution. In Holland’s 1980 parametric profile, radius of maximum wind, maximum wind, and a measure of the profile width describe the radial variation of the axisymmetric wind. Variants of the Holland profile are used to predict insurance underwriting risk...

Conditions for stagnation, recirculation and ventilation potential of the atmosphere were studied in five argentine cities: Resistencia, Cordoba, Buenos Aires, Mar del Plata and Comodoro ́ Rivadavia, located in different regions of the country. Wind run and recirculation factors were calculated for a 24-h transport time using 2 years of hourly surface measurements of wind speed Ž . and direction...

During night-time, with clear-skies and weak-synoptic pressure gradients, the organization of the flow at lower levels is mainly controlled by the local effects, such as terrain or surface heterogeneities. This is the case of the thermal differences between the air adjacent to the slopes and over the nearby plains that generate downslope winds. The foothills of the north Pyrenees are selected t...

Over the last century the Northern Hemisphere has experienced rapid climate warming, but this warming has not been evenly distributed seasonally, as well as diurnally. The implications of such seasonal and diurnal heterogeneous warming on regional and global vegetation photosynthetic activity, however, are still poorly understood. Here, we investigated for different seasons how photosynthetic a...

in order to determine the source and critical areas of wind erosion, sistan plain, irifr-e.a method was applied. according to geomorphological investigations, the studied area consists of the following two main units namely: pediment with 1 type and 8 geomorphological facies, and playa with 2 types of flatland and desert type that includes 9 geomorphological facies. on the basis of sediment, th...

The location of the Niwot Ridge Ameriflux site within the rocky mountains subjects it to airflows which are common in mountainous terrain. In this study, we examine the effects of some of these mesoscale features on local turbulent flux measurements; most notably, the formation of valley/mountain flows and mountain lee-side waves. The valley/mountain flows created local non-stationarities in th...

BAJWA, KANWARDEEP SINGH. Measurements and Modeling of Emissions, Dispersion and Dry Deposition of Ammonia from Swine Facilities. (Under the direction of Dr. Viney P. Aneja and Dr. S. Pal Arya). Ammonia has recently gained importance for its increasing atmospheric concentrations and its role in the formation of aerosols. Studies have shown increasing atmospheric concentration levels of NH3 and N...