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Michael Ghil and Kingtse Mo

752 JOURNAL OF THE ATMOSPHERIC SCIENCES VOL. 48, No. 5Intraseasonal Oscillations in the Global Atmosphere.Part I: Northern Hemisphere and Tropics MICHAEL GHILClimate Dynamics Center, Department of Atmospheric Sciences, and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, California KINGTSE MOClimate Analysis Center

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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

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Anne K. Smith, Rolando R. Garcia, Andrew C. Moss, and Nicholas J. Mitchell

at 20 hPa. This may be due to the coarser latitudinal resolution of the SABER data since the westerly phase of the QBO is narrowly confined to the deep tropics. The month-to-month variability does not always agree. The satellite winds show more month-to-month variability during periods of strong westerly wind; both the satellite and Singapore winds are variable during periods of strong easterly wind. There could also be a systematic discrepancy between zonally averaged satellite winds and single

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Paul R. Field, Andrew J. Heymsfield, and Aaron Bansemer

. Therefore, if any systematic errors are introduced by the probe analysis, they will be present in both datasets. For the development of the parameterization and subsequent testing the two new datasets were formed by combining the tropical and midlatitude “a” and the tropical and midlatitude “b” sets to form two new independent sets: “a” and “b.” The parameterization that will be presented later has been derived from set “a” and then tested using set “b.” 3. Tropics versus midlatitude It is instructive

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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

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Valentin Louf, Alain Protat, Robert A. Warren, Scott M. Collis, David B. Wolff, Surendra Raunyiar, Christian Jakob, and Walter A. Petersen

and 2007, to reduce the data size and to allow real-time transmission to the regional forecasting office, the radar gate range was changed to 300 m, and data were sampled with an azimuthal resolution of 1.5°. Before 2007, the azimuthal indexing had to be corrected while, after 2007, the data are generated with the data synced to the azimuthal sampling. CPOL has produced more than 350 000 plan position indicator scans over 17 wet seasons (November–May). Because of its location in the tropics and

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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

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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

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Hai Lin, Jacques Derome, and Gilbert Brunet

1. Introduction One of the most important climate signals that has ever been observed is El Niño–Southern Oscillation (ENSO). It has a considerable impact on the atmospheric circulation not only in the Tropics, but also in the middle and high latitudes. ENSO is believed to be responsible for a dominant part of the skill in seasonal weather predictions (e.g., Kumar and Hoerling 1995 ; Shukla et al. 2000 ; Derome et al. 2001 ). Studies aimed at understanding the atmospheric response to ENSO

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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

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