Atmospheric Research 145–146 (2014) 12–26
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Atmospheric Research
journal homepage: www.elsevier.com/locate/atmos
Long-term trends and extremes in observed daily precipitation
and near surface air temperature in the Philippines for the
period 1951–2010
Thelma A. Cinco a, Rosalina G. de Guzman a, Flaviana D. Hilario a, David M. Wilson b,c,d,⁎
a
b
c
d
Philippine Atmospheric, Geophysical & Astronomical Services Administration (PAGASA), Quezon City, Manila, Philippines
University of the Philippines, Los Baños, Laguna, Philippines
International Centre for Research in Agroforestry, Los Baños, Laguna, Philippines
Oscar M. Lopez Center for Climate Change Adaptation and Disaster Risk Management Foundation, Philippines
a r t i c l e
i n f o
Article history:
Received 9 September 2013
Received in revised form 14 March 2014
Accepted 24 March 2014
Available online 5 April 2014
Keywords:
Climate change
Trend analysis
Climate extremes
Precipitation
Air temperature
a b s t r a c t
Observed daily precipitation and near surface air temperature data from 34 synoptic weather
stations in the Philippines for the period 1951–2010 were subjected to trend analysis which
revealed an overall warming tendency compared to the normal mean values for the period
1961–1990. This warming trend can be observed in the annual mean temperatures, daily
minimum mean temperatures and to a lesser extent, daily maximum mean temperatures.
Precipitation and temperature extremes for the period 1951–2010 were also analysed relative
to the mean 1961–1990 baseline values. Some stations (Cotabato, Iloilo, Laoag and Tacloban,)
show increases in both frequency and intensity of extreme daily rainfall events which are
significant at the 95% level with none of the stations showing decreasing trends. The frequency
of daily temperature maximum above the 99th percentile (hot days) and nights at the 1st
percentile (cold nights) suggests that both days and nights in particular are becoming warmer.
Such indicators of a warming trend and increase in extreme events in the Philippines are
discussed in the context of similar national, regional (Asia Pacific) and global studies. The
relevance of such empirically based climatology studies, particularly for nations such as the
Philippines which are increasingly vulnerable to the multiple impacts of global climate change,
is also considered.
© 2014 Published by Elsevier B.V.
1. Introduction
Climate trends and climatic extreme indices derived from
empirical, observed data indicate that global average surface
temperatures have been increasing since the mid-19th
century with the greatest rate of change observable since
the mid-1970s (Alexander et al., 2006; Frich et al., 2002;
IPCC, 2007, 2013a; Quirk, 2012). Correspondingly, in East
⁎ Corresponding author at: OML Partnership Office, World Agroforestry Center
(ICRAF), Philippines Country Office, 2nd Floor, Khush Hall Building, International
Rice Research Institute, PO Box 35024, UPLB College, Los Baños, Laguna 4031,
Philippines. Tel.: +63 49 536 2925, +63 49 536 7645.
http://dx.doi.org/10.1016/j.atmosres.2014.03.025
0169-8095/© 2014 Published by Elsevier B.V.
and Southeast Asia, a number of studies reveal a warming
trend with increased mean surface temperatures for both
inter-seasonal and inter-annual means at the national and
regional scale (Cruz et al., 2007; Su et al., 2005; Yue and
Hashino, 2003). The most recent Intergovernmental Panel on
Climate Change Fifth Assessment Report (IPCC AR5) provides
the strongest indication to date that climate change is
“unequivocal”, that changes since the mid-20th century are
“unprecedented” and that this is very likely due to an
increase in the atmospheric concentration of anthropogenic
greenhouse gases (IPCC, 2013a). Continued increases in
greenhouse gas (GHG) emissions and atmospheric concentrations may see global average surface warming reach as