AIR SURFACE TEMPERATURE CORRELATION WITH GREENHOUSE GASES USING AIRS DATA OVER PENINSULAR MALAYSIA
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Date
2011-08
Authors
RAJAB HUSSAIN, JASIM MOHAMMED
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Abstract
The main objective of this study is to develop four regression equationsdenoted
ASTl, AST2, PCAl (03 NEM season), and PCA2 (03 SWM season)-that
will then be used to calculate the air surface temperature (AST) and total column
ozone (OJ). In addition, this study seeks to analyse and investigate the impacts of
greenhouse gases (GHGs) on the AST value and several atmospheric parameters on
0 3 values in Peninsular Malaysia. Multiple linear and principal component
regression methods have been used to achieve the objectives of the study.
The predicted ASTl (R= 0.821} and AST2 (R= 0.783) were highly correlated
with GHGs for the six-year (2003-2008) data. Comparisons among five stations in
2009 showed close agreement between the predicted ASTl and AST2 and the
observed AST from AIRS, especially in the SWM season, within 1.3 K, and for in
situ data, within 1-2 K. The validation results of both ASTl and AST2 with AST
from AIRS showed high correlation coefficient (R= 0.845 - 0.918) and (R= 0.808 -
0.878), respectively, providing indication of both equations efficiency and accuracy.
Statistical analysis in term of P showed that H20vapour (0.565-1. 7 46) tended to
contribute significantly to high AST values during the NEM season. H20vapour
(1.042-2.036) and 0 3 during the SWM season were indicated by the strongly
positive P (0.421-0.864). CO has a moderately positive P (0.125-0.96) associated
with AST values, and CH4 (-0.525-0.426) is also an important parameter in
determining the variability of the AST value. C02 yields a reasonable relationship
with AST by low to moderate p values (between -0.065 and 0.238).
The result of fitting the best regression equations for the 0 3 data gave close to
the same values ofR (~ 0.93) and R2 (~ 0.86) for both the NEM and SWM seasons.
The common variables that appeared in both equations PCAI and PCA2 were the
SSKT, CH4 and RH, and the principal precursor of the 0 3 value in both NEM and
SWM seasons was SSKT. The obtained validation results between the predicted and
observed 03 showed high R (0.845-0.942) is evidence of the 0 3 regression equations
efficiency. Generally, these results clearly indicate the advantage of using the satellite
AIRS data and a correlation analysis study to investigate the impact of atmospheric
GHGs on AST over peninsular Malaysia. Regression equations developed capable of
retrieving Peninsular Malaysian AST in all weather conditions with total
uncertainties ranging betweenl-2 K.
Description
Keywords
AIR SURFACE TEMPERATURE , GREENHOUSE GASES USING