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Title: Principal component analysis of vertical profiles of Q[sub 1] and Q[sub 2] in the tropics

Abstract

Rotated principal component analysis (PCA) is applied to the combined vertical profiles of apparent heat source Q[sub 1] and apparent moisture sink Q[sub 2] from both disturbed and undisturbed periods of the Australian summer monsoon season. The data represent the heating and drying within two radiosonde arrays afforded by the Australian Monsoon Experiment (AMEX). The aim here is to identify dominant modes of variability in combined vertical profiles of Q[sub 1] and Q[sub 2]. Rotation of the principal components (PCs) - done to assure stable, physically meaningful components - yields several PCs, deemed here to be statistically significant. The variation of individual Q[sub 1] and Q[sub 2] profiles from the mean profile can be expressed as linear combinations of the PCs; therefore, determination of the relative importance of each PC (through examination of its score) during differing convective conditions provides insight into their physical meaning. For instance, the contribution of PC 1 (that mode of variability that explains the maximum amount of variance between the profiles) is largest when mature cloud-cluster coverage is most expansive. Therefore, this PC is attributable to that combination of deep convection and associated stratiform anvil typical of mature cloud clusters. The remaining PCs fall intomore » two categories: those whose contributions vary with the evolution of a convective system and those whose contributions vary diurnally. Principal components of the former group represent the effects of convection from shallow cumulus to stratiform anvil precipitation. Principal components of the latter group, those that show heating and drying patterns confined to the extremities of the troposphere, are attributable to diabatic boundary-layer fluxes and radiative processes at the top of the troposphere. 64 refs., 10 figs., 2 tabs.« less

Authors:
; ;  [1]
  1. Pennsylvania State Univ., University Park (United States)
Publication Date:
OSTI Identifier:
6721370
Resource Type:
Journal Article
Journal Name:
Monthly Weather Review; (United States)
Additional Journal Information:
Journal Volume: 121:2; Journal ID: ISSN 0027-0644
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; MONSOONS; ATMOSPHERIC PRECIPITATIONS; CONVECTION; TROPOSPHERE; DRYING; HEATING; AUSTRALIA; CLOUDS; METEOROLOGY; ROTATION; TROPICAL REGIONS; AUSTRALASIA; DEVELOPED COUNTRIES; DISASTERS; EARTH ATMOSPHERE; ENERGY TRANSFER; HEAT TRANSFER; MASS TRANSFER; MOTION; STORMS; 540110*

Citation Formats

Alexander, G D, Young, G S, and Ledvina, D V. Principal component analysis of vertical profiles of Q[sub 1] and Q[sub 2] in the tropics. United States: N. p., 1993. Web. doi:10.1175/1520-0493(1993)121<0535:PCAOVP>2.0.CO;2.
Alexander, G D, Young, G S, & Ledvina, D V. Principal component analysis of vertical profiles of Q[sub 1] and Q[sub 2] in the tropics. United States. https://doi.org/10.1175/1520-0493(1993)121<0535:PCAOVP>2.0.CO;2
Alexander, G D, Young, G S, and Ledvina, D V. 1993. "Principal component analysis of vertical profiles of Q[sub 1] and Q[sub 2] in the tropics". United States. https://doi.org/10.1175/1520-0493(1993)121<0535:PCAOVP>2.0.CO;2.
@article{osti_6721370,
title = {Principal component analysis of vertical profiles of Q[sub 1] and Q[sub 2] in the tropics},
author = {Alexander, G D and Young, G S and Ledvina, D V},
abstractNote = {Rotated principal component analysis (PCA) is applied to the combined vertical profiles of apparent heat source Q[sub 1] and apparent moisture sink Q[sub 2] from both disturbed and undisturbed periods of the Australian summer monsoon season. The data represent the heating and drying within two radiosonde arrays afforded by the Australian Monsoon Experiment (AMEX). The aim here is to identify dominant modes of variability in combined vertical profiles of Q[sub 1] and Q[sub 2]. Rotation of the principal components (PCs) - done to assure stable, physically meaningful components - yields several PCs, deemed here to be statistically significant. The variation of individual Q[sub 1] and Q[sub 2] profiles from the mean profile can be expressed as linear combinations of the PCs; therefore, determination of the relative importance of each PC (through examination of its score) during differing convective conditions provides insight into their physical meaning. For instance, the contribution of PC 1 (that mode of variability that explains the maximum amount of variance between the profiles) is largest when mature cloud-cluster coverage is most expansive. Therefore, this PC is attributable to that combination of deep convection and associated stratiform anvil typical of mature cloud clusters. The remaining PCs fall into two categories: those whose contributions vary with the evolution of a convective system and those whose contributions vary diurnally. Principal components of the former group represent the effects of convection from shallow cumulus to stratiform anvil precipitation. Principal components of the latter group, those that show heating and drying patterns confined to the extremities of the troposphere, are attributable to diabatic boundary-layer fluxes and radiative processes at the top of the troposphere. 64 refs., 10 figs., 2 tabs.},
doi = {10.1175/1520-0493(1993)121<0535:PCAOVP>2.0.CO;2},
url = {https://www.osti.gov/biblio/6721370}, journal = {Monthly Weather Review; (United States)},
issn = {0027-0644},
number = ,
volume = 121:2,
place = {United States},
year = {Mon Feb 01 00:00:00 EST 1993},
month = {Mon Feb 01 00:00:00 EST 1993}
}