Search Results

You are looking at 71 - 80 of 154 items for :

  • Anthropogenic effects x
  • Journal of Atmospheric and Oceanic Technology x
  • User-accessible content x
Clear All
J. Heintzenberg, A. Wiedensohler, T. M. Tuch, D. S. Covert, P. Sheridan, J. A. Ogren, J. Gras, R. Nessler, C. Kleefeld, N. Kalivitis, V. Aaltonen, R-T. Wilhelm, and M. Havlicek

research since the 1950s ( Ruppersberg 1959 ). Many modifications and a large number of applications of this type of instrument emerged over the past 50 yr. Relevant for the present investigation is the addition of a backscatter shutter to measure hemispheric backscatter coefficients ( Waggoner et al. 1972 ). A review of this type of instrument was prepared by Heintzenberg and Charlson (1996) . With increasing attention to possible radiative forcing of climate by anthropogenic aerosols ( Charlson et

Full access
T. Machida, H. Matsueda, Y. Sawa, Y. Nakagawa, K. Hirotani, N. Kondo, K. Goto, T. Nakazawa, K. Ishikawa, and T. Ogawa

1. Introduction Atmospheric greenhouse gases have been increasing exponentially because of anthropogenic activities, such as large deforestation and fossil fuel combustion. The growth rate of atmospheric carbon dioxide (CO 2 ) for the 1995–2005 period was 1.9 ppm yr −1 , the largest in any decade over the last 200 yr ( Forster et al. 2007 ). To predict the future CO 2 level with a sufficient degree of reliability, a quantitative understanding of the global carbon cycle is necessary. Top

Full access
Jost Heintzenberg and Robert J. Charlson

. However, the lack of analyses of theother chemical species that had to be present, notablythe cation associated with the SO 42-, prevented a properdetermination of the partial derivative in Eq. (8.1).Much more thorough chemical analyses became possible in the early 1980s with the advent of ion chromatography, leading to more extensive efforts to attribute scattering to individual chemical compounds and,thence, to sources (White 1986).9. Studies of effects of relative humidity, ammonia, and

Full access
Zheng Ki Yip and M. K. Yau

1. Introduction Intense tropical cyclones represent one of the most violent atmospheric phenomena. The possible change in tropical cyclone (TC) frequency and intensity in a future warming climate therefore has severe socioeconomic implications. In addition, the problem is of significant scientific concern in terms of the effects of TCs on other components of the climate system through direct or indirect feedbacks. However, the accurate projection of TC frequency and intensity in the future is

Full access
Lynn M. Russell, Shou-Hua Zhang, Richard C. Flagan, John H. Seinfeld, Mark R. Stolzenburg, and Robert Caldow

theimpact of anthropogenic emissions on cloud properties. Theoretical studies have predicted that both marineand anthropogenically influenced tropospheric aerosols Corresponding author address: Prof. John H. Seinfeld, Divisionof Engineering and Applied Science, California Institute of Technology, 104-44, Pasadena, CA 91125.should vary diurnally as a result of photochemical reactions resulting in secondary new particle formationand aerosol growth (Russell et al. 1994). Such worksuggests that the

Full access
Dietrich Althausen, Detlef Müller, Albert Ansmann, Ulla Wandinger, Helgard Hube, Ernst Clauder, and Steffen Zörner

effects and signal-induced noise. If necessary, signals are reduced with neutral-density filters in front of the interference filters. Simultaneous to signal acquisition the raw data are transferred to a personal computer and displayed online as a color-coded plot. This quick-look feature serves as a fast way of monitoring the measurement in terms of instrument performance, atmospheric conditions, and present particle layers. c. Stability and alignment The entire system is mounted in a framework

Full access
Peiyang Cheng, Arastoo Pour-Biazar, Richard T. McNider, and John R. Mecikalski

-scale coverage over contiguous United States (CONUS) and physically describes cloud radiative effects ( Gautier et al. 1980 ; Habte et al. 2012 ; Schmetz 1989 ). Previous studies have shown that, compared to surface measurements, standard errors for satellite-estimated insolation are typically 15%–20% on an hourly basis and about 10% for daily estimates ( Jacobs et al. 2002 ; Schmetz 1989 ; Pinker et al. 1995 ). However, the accuracy of these retrievals decreases as the variability of cloud fields

Free access
E. J. Hintsa, G. P. Allsup, C. F. Eck, D. S. Hosom, M. J. Purcell, A. A. Roberts, D. R. Scott, E. R. Sholkovitz, W. T. Rawlins, P. A. Mulhall, K. Lightner, W. W. McMillan, J. Song, and M. J. Newchurch

regional and intercontinental) of anthropogenic emissions, including ozone and ozone precursors (e.g., National Academy of Sciences 2001 ). Intercontinental transport occurs almost by definition across oceans, with the principal pathways being export from North America to Europe over the Atlantic Ocean (e.g., Stohl and Trickl 1999 ; Li et al. 2002 ) and transport from Asia to North America across the Pacific ( Jaffe et al. 1999 ). To address this, air and ground-based studies have been conducted

Full access
Ji Yeon Park, Sungil Lim, and Kihong Park

than 0.45 μm, and were homogeneously mixed using a magnetic stirrer. Natural seawater samples were obtained from coastal areas near Pohang (latitude: 36°05′05″, longitude: 129°38′26″) (East Sea of Korea), Taean (latitude: 36°74′22″, longitude: 126°07′43″) (West Sea of Korea), and Yeosu (latitude: 34°57′36″, longitude: 127°79′88″) (South Sea of Korea) in July 2010; the selected sampling sites had nearby few anthropogenic sources. Seawater sampled at the Taean site is known to have the strongest

Full access
Kenneth E. Kunkel, Michael A. Palecki, Kenneth G. Hubbard, David A. Robinson, Kelly T. Redmond, and David R. Easterling

effects. Snow is an important component of annual runoff, recharge, and water supplies, and greatly affects water management in the northern and western United States. Rapid melt of snowpack is a major cause of floods in the northern United States. Recent studies have examined historical variability in snow cover ( Hughes and Robinson 1996 ; Frei et al. 1999 ). However, studies of trends in other aspects of snow climatology, such as snowfall and snow depth, have generally examined records from the

Full access