Precipitation variability associated with the North American Monsoon in the 20th century

Abstract. A 2-year data set of measured CCN (cloud condensation nuclei) concentrations at 0.2 % supersaturation is combined with aerosol size distribution and aerosol composition data to probe the effects of aerosol number concentrations, size distribution and composition on CCN patterns. Data were collected over a period of 2 years (2012–2014) in central Tucson, Arizona: a significant urban area surrounded by a sparsely populated desert. Average CCN concentrations are typically lowest in spring (233 cm−3), highest in winter (430 cm−3) and have a secondary peak during the North American monsoon season (July to September; 372 cm−3). There is significant variability outside of seasonal patterns, with extreme concentrations (1 and 99 % levels) ranging from 56 to 1945 cm−3 as measured during the winter, the season with highest variability. Modeled CCN concentrations based on fixed chemical composition achieve better closure in winter, with size and number alone able to predict 82 % of the variance in CCN concentration. Changes in aerosol chemical composition are typically aligned with changes in size and aerosol number, such that hygroscopicity can be parameterized even though it is still variable. In summer, models based on fixed chemical composition explain at best only 41 % (pre-monsoon) and 36 % (monsoon) of the variance. This is attributed to the effects of secondary organic aerosol (SOA) production, the competition between new particle formation and condensational growth, the complex interaction of meteorology, regional and local emissions and multi-phase chemistry during the North American monsoon. Chemical composition is found to be an important factor for improving predictability in spring and on longer timescales in winter. Parameterized models typically exhibit improved predictive skill when there are strong relationships between CCN concentrations and the prevailing meteorology and dominant aerosol physicochemical processes, suggesting that similar findings could be possible in other locations with comparable climates and geography.

Download Full-text

Observed relation between evapotranspiration and soil moisture in the North American monsoon region

Geophysical Research Letters ◽

10.1029/2008gl036001 ◽

2008 ◽

Vol 35 (22) ◽

Cited By ~ 102

Author(s):

Enrique R. Vivoni ◽

Hernan A. Moreno ◽

Giuseppe Mascaro ◽

Julio C. Rodriguez ◽

Christopher J. Watts ◽

...

Keyword(s):

Soil Moisture ◽

North American ◽

North American Monsoon ◽

Monsoon Region ◽

The North

Download Full-text

Board to Page to Board

Board Game Studies Journal ◽

10.1515/bgs-2016-0002 ◽

2016 ◽

Vol 10 (1) ◽

pp. 17-31 ◽

Cited By ~ 1

Author(s):

Philip M. Winkelman

Keyword(s):

Native American ◽

20Th Century ◽

American Indians ◽

North American ◽

Intelligent Design ◽

Typically Develop ◽

North American Indians ◽

The North ◽

Gradual Evolution

Abstract The ways new games typically develop might be viewed as a continuum ranging from very gradual “evolution” based on mutations introduced to a single progenitor during play or recall, to sudden “intelligent design” based on a purposeful and original combination — or even invention — of ludemes independent of any particular lines of transmission. This paper argues that two proprietary 20th-century games, C.A. Neves’s Fang den Hut! and Lizzie Magie’s The Landlord’s Game, were developed in a different way, a bit outside the typical continuum. It analyzes the games’ general typologies, and specific ludemes, concluding that both games are modern adaptations of traditional Native American games encountered, not through play or even contact with players, but through the seminal ethnographic publications of Stewart Culin. Specifically, Fang den Hut! derives from Boolik via Games of the North American Indians, and The Landlord’s Game derives from Zohn Ahl via Chess and Playing-Cards.

Download Full-text