Search Results

You are looking at 91 - 100 of 17,321 items for :

  • All content x
Clear All
Natalia Hasler, David Werth, and Roni Avissar

Gornitz 1984 ; Henderson-Sellers et al. 1993 ) and the Rossby waves, which propagate from the tropics into the midlatitudes ( Gedney and Valdes 2000 ). These changes in circulation can ultimately modify the remote climate, a mechanism known as “teleconnection.” While studies of the local impact of large-scale deforestation have produced fairly consistent results ( Henderson-Sellers et al. 1993 ), possible teleconnections are still controversial ( Findell and Knutson 2006 ). Earlier studies indicate

Full access
V. Sivakumar, H. Bencherif, N. Bègue, and A. M. Thompson

a decrease in the global tropopause pressure of ~1.82 hPa (10 yr) −1 based on the NCEP–National Center for Atmospheric Research analysis data from 1979 to 1997 and of ~2.16 hPa from 1979 to 2000. Schmidt et al. (2004) derived tropical tropopause parameters from the global positioning system and found that the tropopause had a strong meridional variability in structure on the basis of 3 yr (2001–03) of data. Over the tropics (30°S–30°N), they found that the tropopause and the associated

Full access
Guido Vettoretti, Marc d’Orgeville, William R. Peltier, and Marek Stastna

may be transmitted meridionally into the tropics and zonally to other midlatitude locations. In particular, we will focus upon the impact of changes in AMOC on one of the main modes of interannual global climate variability, the El Niño–Southern Oscillation (ENSO) phenomenon. ENSO, a coupled ocean–atmosphere dynamical process, is characterized by enhanced spectral variability of Pacific sea surface temperatures (SSTs) with a time scale of 2–7 yr (for a recent review of the phenomenon itself, see

Full access
Chris Kent, Robin Chadwick, and David P. Rowell

1. Introduction The tropical regions, home to approximately 40% of the world’s population ( State of the Tropics 2014 ), a large proportion of developing countries, and some of the most biodiverse areas in the world, are highly reliant on precipitation. The timing, intensity, and frequency of precipitation in the tropics can have a significant impact on livelihoods, particularly impacting freshwater availability and agriculture. For example, agriculture in Africa is almost entirely rain

Full access
Steven W. Lyons

AUaVST 1981 STEVEN W. LYONS 1773Planetary-Scale Aspects of Outgoing Longwave Radiation and Vorticity over the Global Tropics during Winter~ STEVEN W. LYONSDepartment of Meteorology, University of Hawaii, Honolulu 96822(Manuscript received 27 May 1980, in final form 8 April 1981) ABSTRACT Fourier analysis was applied to outgoing

Full access
Muthuvel Chelliah and Phillip Arkin

371APRIL 1992CHELLIAH AND ARKINMUTHUVEL CHELLIAH *Climate Analysis Center, NMC/NWS/NOAA, Washington, D.C.PHILLIP ARKINOf/ice of Climate and Atmospheric Research, NOAA, Rockville, Maryland(Manuscript received 23 March 1990, in final form 7 January 1991)ABSTRACTThe objective of this study is to examine the broad aspects of large-scale interannual and long-term variabilityin the monthly mean outgoing longwave radiation (OLR) data over the global tropics. These data, denvedfrom NOAA's polar

Full access
Christian Jakob and Courtney Schumacher

1. Introduction The weather and climate of the tropics are driven by the interaction of large-scale circulation features and convection. The mean tropical climate and its seasonal variation are characterized by easily distinguishable migrating bands of high values of precipitation in the intertropical convergence zone (ITCZ). The largest interannual tropical variation, the El Niño–Southern Oscillation (ENSO) phenomenon, is associated with the movement of regions of active convection between the

Full access
Tsing-Chang Chen

JULY 1983 TSING-CHANG CHEN 1389The Energy Exchange between the Baroclinic and Barotropic Components of Atmospheric Flow in the Tropics during the FGGE Summer TSING-CH^NG CHENDepartment of Earth Sciences, Iowa State University, Ames, 50011(Manuscript received 15 November 1982, in final form 11 April 1983)ABSTRACT The wind fields in

Full access
Lorenzo Tomassini

Convection–circulation interaction sets the tone in the tropics The interaction between moist convection and the atmospheric circulation in the tropics takes place on a large range of scales, from the mesoscale dynamics of organized convective systems ( Houze 1977 ; Houze and Betts 1981 ; Hartmann et al. 1984 ; Houze 1989 , 2004 ), to synoptic-scale tropical disturbances like convectively coupled waves ( Riehl 1945 ; Reed and Recker 1971 ; Lau and Lau 1990 ), and large-scale overturning

Full access
Ángel F. Adames

related to the amplitude of the low-frequency background precipitation. Furthermore, the importance of the precipitation sensitivity parameter a becomes clearer, as it determines the magnitude of precipitation variability. This relation shows that moisture-driven precipitation perturbations are more relevant over the climatologically rainy regions of the tropics. Figure 3 shows the relationship between annual-mean precipitation and the standard deviation of 20–100-day-filtered precipitation

Full access