跳至主要内容

Convective Rainfall Systems in the La Plata Basin

Read full paper at:
http://www.scirp.org/journal/PaperInformation.aspx?PaperID=51127#.VFbQcWfHRK0

Hourly rainfall estimates from integrated satellite data are used to build a dynamically based climatology of convectively generated rainfall across the La Plata Basin in South America and adjacent oceans. Herein, the focus of this manuscript is on 20S to 35S, including the Andes cordillera. Emphasis is placed on rainfall resulting from organized convective regimes which are known to produce the majority of seasonal rainfall in Southern South America and other continents. The statistical characteristics of individual events are quantified and examined with respect to regional atmospheric conditions. Among the factors considered are steering winds and wind shear, convective available potential energy (CAPE), localized sensible and latent heat sources over mountains and wetlands (Chaco), and the occurrence of baroclinic waves such as mid-latitude jet stream transient disturbances. Forcing and convective triggering mechanisms are inferred from the diagnosis of systematic patterns as evidenced in the continental diurnal cycle and longer periods of natural variability. The diurnal cycle of rainfall is especially informative with respect to the frequency and phase of rainfall associated with long-lived propagating rainfall “episodes”. Similar to findings in tropical northern Africa and tropical northern Australia, there is a strong presence of organized convection, which can propagate zonally hundreds to thousands of km as a coherent sequence of mesoscale convective systems. Convective triggering is often associated with elevated terrain, the Andes, and the La Plata basin region, which is especially rich in moist static energy. The passage of baroclinic waves over the Andes is consistent with eastward propagating clusters of convection, within which westward-propagating systems also reside. These organized convective systems over the La Plata Basin are analyzed with hourly rainfall estimates with CMOPRH method. Rainfall estimates at 8-km spatial resolution were obtained between December 2002 and June 2008. Very few data are missing so it is one of the most complete, longest and highest resolution data sets available to date that allows a comprehensive description of spatial and temporal distribution of convection from its hourly to interannual variability over the region. In this work, diurnal, intra and inter seasonal and interannual cycles are obtained and examined in the light of episodes of organized convection. Daily, monthly and yearly spatial patterns of rainfall accumulation over the La Plata Basin region vary both inter- and intra-seasonally and are forced by underlying dynamic and thermodynamics mechanisms. Time-longitude diagrams of CMORPH hourly rainfall are used to describe the genesis, structure, longevity, phase speed and inferences of the underlying dynamics and thermodynamics of episodes of organized convection. The episodes of organized convection are analyzed in terms of their duration, span, phase speed, starting and ending time, starting and ending longitude, month and year through frequency distribution analysis. Most episodes of organized convection move eastward across the La Plata Basin with variable phase speeds. Basic descriptive statistics indicate that the La Plata eastward propagating average phase speed is 13.0 m·s-1.
Cite this paper
Filho, A. , Carbone, R. and Tuttle, J. (2014) Convective Rainfall Systems in the La Plata Basin. Atmospheric and Climate Sciences, 4, 757-778. doi: 10.4236/acs.2014.44068. 
 

[1] Velasco, I. and Fritsch, J.M. (1987) Mesoscale Convective Complexes in the Americas. Journal of Geophysical Research, 92, 9591-9613. http://dx.doi.org/10.1029/JD092iD08p09591
[2] Laing, A.G. and Fritsch, J.M. (1993) Mesoscale Convective Complexes over the Indian Monsoon Region. Journal of Climate, 6, 911-919.
http://dx.doi.org/10.1175/1520-0442(1993)006<0911:MCCOTI>2.0.CO;2
[3] Vera, C., Baez, J., Douglas, M., Emmanuel, C.B., Marengo, J., Meitin, J., Nicolini, M., Nogues-Paegle, J., Paegle, J., Penalba, O., Salio, P., Saulo, C., Silva Dias, M.A., Silva Dias, P. and Zipser, E. (2006) The South American Low-Level Jet Experiment (SALLJEX). Bulletin of the American Meteorological Society, 87, 63-77. http://dx.doi.org/10.1175/BAMS-87-1-63
[4] Joyce, R.J., Janowiak, J.E., Arkin, P.A. and Xie, P. (2004) CMORPH: A Method That Produces Global Precipitation Estimates from Passive Microwave and Infrared Data at High Spatial and Temporal Resolution. Journal of Hydrometeorology, 5, 487-503.
http://dx.doi.org/10.1175/1525-7541(2004)005<0487:CAMTPG>2.0.CO;2
[5] Huffman, G.J., Adler, R.F., Bolvin, D.T., Gu, G., Nelkin, E.J., Bowman, K.P., Hong, Y., Stocker, E.F. and Wolff, D.B. (2007) The TRMM Multi-Satellite Precipitation Analysis: Quasi-Global, Multi-Year, Combined-Sensor Precipitation Estimates at Fine Scale. Journal of Hydrometeorology, 8, 38-55.
http://dx.doi.org/10.1175/JHM560.1
[6] Hsu, K.-L., Gao, X., Sorooshian, S. and Gupta, V. (1997) Precipitation Estimation from Remotely Sensed Information Using Artificial Neural Networks. Journal of Applied Meteorology, 36, 1176-1190.
http://dx.doi.org/10.1175/1520-0450(1997)036<1176:PEFRSI>2.0.CO;2
http://dx.doi.org/10.1175/2009JHM1139.1
[7] Ebert, E.E., Janowiak, J.E. and Kidd, C. (2007) Comparison of Near Real Time Precipitation Estimates from Satellite Observations and Numerical Models. Bulletin of the American Meteorological Society, 88, 47-64http://dx.doi.org/10.1175/BAMS-88-1-47
[8] Pereira Filho, A.J., Carbone, R.E., Janowiak, J.E., Arkin, P., Joyce, R., Hallak, R. and Ramos, C.G.M. (2009) Satellite Rainfall Estimates over South America: Possible Applicability to the Water Management of Large Watersheds. Journal of the American Water Resources Association, 46, 344-360.
http://dx.doi.org/10.1111/j.1752-1688.2009.00406.x
[9] Peixoto, J.P. and Oort, A.H. (1992) Physics of Climate. American Institute of Physics, College Park, 520 p.
[10] Carbone, R.E., Tuttle, J.D., Ahijevych, D.A. and Trier, D.S.B. (2002) Inferences of Predictability Associated with Warm Season Precipitation Episodes. Journal of the Atmospheric Sciences, 59, 2033-2056. http://dx.doi.org/10.1175/1520-0469(2002)059<2033:IOPAWW>2.0.CO;2
[11] Liu, C. and Zipser, E.J. (2008) Diurnal Cycles of Precipitation, Clouds and Lightning in the Tropics from 9 Years of TRMM Observations. Geophysical Research Letters, 35, Article ID: L04819.
http://dx.doi.org/10.1029/2007GL032437
[12] Keenan, T.D. and Carbone, R.E. (2008) Propagation and Diurnal Evolution of Warm Season Cloudiness in the Australian and Maritime Continent Region. Monthly Weather Review, 136, 973-994.
http://dx.doi.org/10.1175/2007MWR2152.1
[13] Laing, A.G., Carbone, R., Levizzani, V. and Tuttle, J. (2008) The Propagation and Diurnal Cycles of Deep Convection in Northern Tropical Africa. Quarterly Journal of the Royal Meteorological Society, 134, 93-109. http://dx.doi.org/10.1002/qj.194
[14] Gan, M.A. and Rao, V.B. (1991) Surface Cyclogenesis over South America. Monthly Weather Review, 119, 1293-1302. http://dx.doi.org/10.1175/1520-0493(1991)119<1293:SCOSA>2.0.CO;2
[15] Silva, G.A.M., Ambrizzi, T. and Marengo, J.A. (2009) Observational Evidences on the Modulation of the South American Low Level Jet East of the Andes According the ENSO Variability. Annales Geophysicae, 27, 645-657.http://dx.doi.org/10.5194/angeo-27-645-2009       eww141103lx
标签：

评论

发表评论

此博客中的热门博文

Electron Spin and Proton Spin in the Hydrogen and Hydrogen-Like Atomic Systems

Read full paper at: http://www.scirp.org/journal/PaperInformation.aspx?PaperID=52202#.VIj7tMnQrzE Author(s) Stanisław Olszewski * Affiliation(s) Institute of Physical Chemistry, Polish Academy of Sciences, Warsaw, Poland . ABSTRACT The mechanical angular momentum and magnetic moment of the electron and proton spin have been calculated semiclassically with the aid of the uncertainty principle for energy and time. The spin effects of both kinds of the elementary particles can be expressed in terms of similar formulae. The quantization of the spin motion has been done on the basis of the old quantum theory. It gives a quantum number n = 1/2 as the index of the spin state acceptable for both the electron and proton ...
发表评论
阅读全文

A Study on the Seismic Isolation Systems of Bridges with Lead Rubber Bearings

Read full paper at: http://www.scirp.org/journal/PaperInformation.aspx?PaperID=52566#.VJt06cCAM4 Author(s)   Woo-Suk Kim , Dong-Joon Ahn , Jong-Kook Lee Affiliation(s) School of Architecture, Kumoh National Institute of Technology, Gumi, Republic of Korea . ABSTRACT This study consists of the development and presentation of example of seismic isolation system analysis and design for a continuous, 3-span, cast-in-place concrete box girder bridge. It is expected that example is developed for all Lead-Rubber Bearing (LRB) seismic isolation system on piers and abutments which placed in between super-structure and sub-structure. Design forces, displacements, and drifts are given distinctive consideration in...
发表评论
阅读全文

Effects of Karate Training on Basic Motor Abilities of Primary School Children

“You never attack first in karate” might be the best conclusion of karate, which is a martial art practiced typically without weapons. It’s reported that karate has a long history for several hundred years, but the modern karate was spread to the whole Japan from Okinawa in the early part of 20th century. Now it has become one of the most widely practiced martial art forms in the world. Usually, it’s divided into Kihon, Kata and Kumite. As for the beginners, Kihon is more suitable for them because it involves basic techniques. Due to karate consists of dynamic offensive and defensive techniques using all parts of the body to their maximum advantage, the best understanding of true karate practice is the perfection of oneself through the perfection of the art. It not only develops coordination, quickens reflexes, and builds stamina, but also develops composure, a clearer thought process, deeper insight into one’s mental capabilities, and more self-confidence. So many researchers stu...
发表评论
阅读全文