CLIMATE INDICES IN WEST SUMATERA Sugeng Nugroho Global Atmosphere Watch (GAW) Bukit Kototabang Station Jln. Raya Bukittinggi-Medan Km.17, Palupuh, Kab. Agam, Prop. Sumatera Barat Telp.: , Fax.: International Workshop on The Digitization of Historical Climate Data, The New SACA&D Database and Climate Analysis in The Asean Region April 2012, Citeko, Bogor, Indonesia

OUTLINE INTRODUCTION Background Aim of study METHODOLOGY Site of study Data Data analysis Climate extreme indices RESULTS SUMMARY

INTRODUCTION One of the most significant consequences of global warming due to increase in greenhouse gases would be an increase in magnitude and frequency of climate extreme events (temperature & precipitation ). Background Monitoring CO 2 concentration in Bukit Kototabang GAW Station CO 2 annual average concentration in Bukit Kototabang GAW Station has been increasing from ppm in 2004 to ppm in 2009 The main aim of this study is to determine the annual air temperature variations and extreme rainfall event in West Sumatra by using ETCCDMI extreme indices. Aim of study

METHODOLOGY Study was carried out in Teluk Bayur, Padang and Sicincin as representation of lowland areas, Padang Panjang and Bukit Kototabang for highland areas. Site of study Mentawai Strait

METHODOLOGY This study using daily observation data for the last 20 years at BMKG West Sumatera Stations Data

METHODOLOGY Data were analyzed by using RClimDex 1.0 and nonparametric statistic method (Mann-Kendal test) to analyze the trend variation Data Analysis

METHODOLOGY Using 18 extreme indices from ETCCDMI (Expert Team for Climate Change Detection Monitoring and Indices). Climate Extreme Indices 9 indices for extreme air temperature (TXx, TNx, TXn, TNn, TN10p, TX10p, TN90p, TX90p and DTR) 9 indices were used for extreme rainfall event (RX1D, RX5D, SDII, R125,CDD, CWD, R95p, R99p and PrcpTOT)

Extreme Temperature Indices RESULTS All site show negative trend for TX10p (cool days) index All site show positive trend for TX90p (warm days) index

RESULTS Extreme Rainfall Event Indices All site show positive trend for RX1D (max 1-day prec amount) All site show positive trend for RX5D (max 5-day prec amount) All site show positive trend for R99p (extremely wet days) All site show positive trend for SDII (simple daily intensity index)

1.Result showed that generally the observed areas indicated positive trends for extreme rainfall event indices SUMMARY 2.Extreme air temperature index, positive trends were mostly observed on TXx, TNx, TXn, TNn, TN90p and TX90p indices, whereas negative trends were found on TN10p and TX10p indices 3.Statistical analysis showed not all of trend variations were significant at 95% of convidence level 4.Result suggested that there is no difference between lowlands and highlands in terms of extreme climate condition in West Sumatra.

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