The weather and climate of Malaysia Ahmad Fairudz Jamaluddin Malaysian Meteorological Department Ministry of Science, Technology and Innovation

Outline General Climate of Malaysia Climate Long Term Mean of Malaysia Observed Trend of Climate Extremes in Malaysia How Regional Climate Model can enhance MMD’s services Seasonal / Monthly Weather Outlook Drought Monitoring Fire Danger Rating Summary

GENERAL CLIMATE OF MALAYSIA Tropical maritime climate with: - uniform temperature - high humidity - rainfall throughout the year The seasons:- - Northeast Monsoon (Nov – Mar) - Southwest Monsoon (June – August) - Two Inter-Monsoon (Apr-May & Sept-Oct)

Flood Flash Flood Haze Severe Weather in Malaysia Inter-Monsoon (Apr-May & Sep-Oct) Northeast Monsoon (Nov – Mac) Flood Flash Flood Southwest Monsoon (Jun – Aug) Haze Strong Wind and Rough Sea

Monsoon & Dominant Modes of Climate Variability SWM (Late May to Sept) NEM (Nov to March) PACIFC OCEAN MJO ENSO INDIAN OCEAN IOD Indian Ocean Dipole (IOD), El Nino-Southern Oscillation (ENSO) ---- Interannual oscillation (2-7 years) Madden-Julian Oscillation (MJO) – intra-seasonal oscillation (20-60 days)

Climate Long Term Mean in Malaysia

Monthly Rainfall Over PM Long Term Mean Monthly Rainfall Over PM Northeast Monsoon JANUARY DECEMBER NOVEMBER > 500 Southwest Monsoon JUNE JULY AUGUST

Mean Monthly Average Temperature Over PM Northeast Monsoon Southwest Monsoon

Mean Monthly Average RH Over PM NOVEMBER DECEMBER JANUARY Northeast Monsoon JULY AUGUST SEPTEMBER Southwest Monsoon

Monthly Rainfall Over EM Long Term Mean Monthly Rainfall Over EM DECEMBER JANUARY FEBRUARY Northeast Monsoon 0 – 50 50 – 100 100 – 150 150 – 200 200 – 250 250 – 300 300 – 400 400 – 500 > 500 Southwest Monsoon JULY AUGUST JUNE

Mean Monthly Average Temperature Over EM Northeast Monsoon Southwest Monsoon

Observed Trends of Climate Extremes in Malaysia

CONVECTIVE TIME SCALE Trends in 2 hour maximum rainfall Frequency of Heavy Rainfall (blue) (>20mm) & Intensity (red) for 2 Hour Maximum Rainfall. Number in box indicates trends in PRCPTOT. (Diong et al.; MMD)

SEASONAL TIME SCALE Trends in heavy rainfall Frequency of Heavy Rainfall (blue) (>20mm) & Intensity (red) during Southwest Monsoon (JJA). Number in box indicates trends in PRCPTOT. (Diong et al.; MMD)

SEASONAL TIME SCALE Trends in heavy rainfall Frequency of Heavy Rainfall (blue) (>20mm) & Intensity (red) during Northeast Monsoon (DJF). Number in box indicates trends in PRCPTOT. (Diong et al.; MMD)

ANNUAL TIME SCALE Trends in heavy rainfall Frequency of Heavy Rainfall (blue) (>20mm) & Intensity (red) for annual rainfall. Number in box indicates trends in PRCPTOT. (Diong et al.; MMD)

In general the intensity and frequency of extreme rainfall events are on the rise. The SW monsoon season is becoming wetter but at the same time prolonged dry spells are more frequent. During the NE monsoon season the extreme rainfall events associated with the monsoon surges and other synoptic features are on the rise. Notable increasing trend in the annual precipitation is observed in EM with both the monsoon seasons possibly contributing to this trend.

How Regional Climate Model can enhance MMD’s services

Seasonal / Monthly Weather Outlook

Moisture convergence (mm/day) Moisture flux during JJA (1979-2000) Climate Variability Moisture convergence (mm/day) Moisture flux during JJA (1979-2000) Tangang et. al. (2007) Indian Ocean experience warming SST relatively faster than other oceans including Pacific Ocean Indian Ocean as source of moisture for PM during JJA. South China Sea / Pacific Ocean as source of moisture for Malaysian region during DJF How this SST warming over Indian and Pacific Ocean modulate/change rainfall distribution and extreme weather event over the Malaysian region?

Indian Ocean Dipole (IOD) Composite Anomalous OLR, Mode -ve IOD years, Mode +ve IOD years during JJA Anomalous OLR (W/m2) During Mode –ve IOD, Malaysian region experience neutral condition compare to wetter condition over the South of Sumatra during JJA During Mode +ve IOD, Malaysian region experience dry condition over the south of PM and Sarawak during JJA. However, south of Sumatra and Borneo experience driest condition during the period.

El-Nino Southern Oscillation Index (ENSO) Composite Anomalous OLR & La-Nina years during JJA Anomalous OLR (W/m2) El-Nino years during JJA Wet condition over south of PM and Sarawak during La-Nina. Dry condition over south of PM, Sarawak and south of Sabah during El-Nino (JJA)

Conventional ENSO vs ENSO-Modoki Composites of Anomalous DJF Precipitation Conventional El Nino El Nino Modoki Composites of Anomalous DJF Precipitation, Anomalous wind at 850hPa (Ester Salimun, UKM)

Composites of MJO Phases, Anomalous Precipitation & wind at 925hPa during JJA (Fairudz et. al., MMD)

Diurnal Rainfall and MJO during JJA Phase 1 + 2 Phase 3 + 4 Phase 5 + 6 Phase 7 + 8 Afternoon (15 – 20 MST) Evening (21 – 02 MST) Composites of MJO Phases, standardized anomalous precipitation during afternoon and evening over PM (Fairudz et. al., MMD)

LOCAL ATMOSPERIC CIRCULATION CIN (J/kg) at 20 MST Phase 1 + 2 Afternoon (15 – 20 MST) Stesen Phase 1+2 Phase 3+4 Phase 5+6 Bayan Lepas 75.12 91.56 86.12 KLIA 75.83 59.51 106.5 H CAPE (J/kg) at 20 MST Stesen Phase 1+2 Phase 3+4 Phase 5+6 Kuantan 1972.3 2784.1 2523.6 Relatively low CIN over the west cost of PM during phase 1+2 MJO. Relatively high CAPE over east coast of PM during phase 3+4 MJO. Now we turning to the composite of the MJO and surface circulation during the afternoon period. In upper panel, we see that the sea breeze respond differently to the propagation of MJO. During earlier phases of MJO, the MJO played the main role in allowing the moisture to come into the region. The moisture mostly come from the South China Sea and Indian Ocean. On the other hand, narrow straits of Malacca brings relatively drier air to the region. In lower panel, we see the divergence mostly concentrate over the coastal area. This is due to the interaction of local sea breeze and dominant monsoon wind. To understanding better about the impacts of the MJO, the convective indices were analyze. In upper table, generally peninsular Malaysia experiences relatively weaker CIN in earlier phases of the MJO. As example KLIA, weaker CIN can be observed in earlier phases compared to later, and this is associated with relatively wetter conditions during afternoon period over the region. In lower panel, higher CAPE were observed during the wet phases of the MJO. As example over the Kuantan region, highest CAPE with 2784.18 J/kg observed, these associated with the wetter conditions during late evening period over the region. L Left panel: Composite of MJO’s phase, anomalous mslp (contour), anomalous RH (value) and direction of surface wind (vector). Right panel: Composite of MJO’s phase, anomalous surface divergence, anomalous surface temperature.

Composites of MJO Phases, Anomalous Precipitation & wind at 925hPa during DJF

STATISTICAL DOWNSCALING Probabilistic forecast Statistical downscaling from JMA CGCM (three month lead time and 51 members) Method of “double leave one-out cross-validation” with multiple size of optimal window is used to validate the model at each meteorological station. The highest correlation coefficient with station's precipitation was selected as predictor. SON 2011 Probabilistic forecast for SON 2011 (Yip et. al., MMD)

GCM’S SEASONAL PRODUCTS NDJ NDJ ECMWF JAMSTEC

Rainfall Outlook for November 2012

Meteorology Drought Monitoring

Meteorology Drought Event in Malaysia based on SPI Index Category Number of Events Percentage Drought Event 14 46.6% No Drought Event 16 53.3% Event Number of Events Percentage El-Nino 10 71.4% La-Nina 2 14.2% Others Year (Fatin Nurashikin, UKM) Latest 3-month SPI Index less than -1.0

Meteorology Drought Monitoring & Latest 3-month SPI less than -1.5 LEVEL CONDITIONS WARNING Latest 3-month and 6-monthly cumulative rainfall amount exceed 35% deficit from normal with latest 3-month SPI Indexs less than - 1.5 and the previous drought level was catogorized as ALERT. DANGER Latest 3-month and 6-monthly cumulative rainfall amount exceed 35% deficit from normal with latest 3-month SPI Indexs less than – 2.0 and the previous drought level was catogorized as WARNING. Defisit jumlah hujan kumulatif 3 bulan dan 6 bulan semasa melebihi 35% dari normal dan indeks SPI 3 bulan terkini kurang dari -1.5 serta tahap kemarau sebelumnya telah pun dikategorikan WASPADA. Defisit jumlah hujan kumulatif 3 bulan dan 6 bulan semasa melebihi 35% dari normal dan indeks SPI 3 bulan terkini kurang dari -2.0 serta tahap kemarau sebelumnya telahpun dikategorikan AMARAN.

National & ASEAN Country Fire Danger Rating National & ASEAN Country (currently 3 days forecast (WRF) with 4km resolution for Malaysia & 36km for SEA region

Normal peatswamp (Neutral ENSO - August 2012) Situation of sudden mortality of peatswamp trees (too much water over the area – La-Nina 2011)

North Selangor PSF Sungai Karang FR Raja Musa FR Selangor

Pandangan daripada kompartmen 89 kiri terusan Forest fires at RMFR – August 2012 ( 407 ha)

Pandangan daripada kompartmen 89

Forest fires at RMFR – 2012 ( 407 ha)

FFMC code during 18 – 29 August 2012 19 20 21 22 23 24 25 26 27 28 29

DMC code during 18 – 29 August 2012 19 20 21 22 23 24 25 27 28 26 29

Fire spreading underground (Paya Indah Wetland)

Fire spreading underground (Paya Indah Wetland)

ISI code during 1 – 10 June 2012 ISI : 1 – 10 Jun 2012 1 2 3 4 5 ISI extreme on 4 June 2012, same day burning start (rain on 9 June 2012) ISI : 1 – 10 Jun 2012 6 7 8 9 10

ISI code during 21 – 30 June 2012 ISI : 21 – 30 June 2012 21 22 23 24 25 ISI extreme throughout the burning period except on a few days due to rain (drastic change) ISI : 21 – 30 June 2012 26 27 28 29 30

Summary In general, the intensity and frequency of extreme rainfall events are on rise Climate variability over the Malaysian region is strongly influence by monsoon, ENSO, IOD and MJO Malaysian forestry and water resources are too sensitive to any changes/shifting of the climate Reliable RCMs are crucial and important to enhance MMD’s services such as accurate seasonal/monthly weather outlook, drought monitoring and fire danger rating

15/04/2017 Terima Kasih Dr. Tam Weng Wah

Agriculture; Agro-Climatological Zonation

Suitable not being Planted States State Areas (ha) Actual Planted (A) % Planted Suitable (S) % Suitable Suitable not being Planted Johor 1,891,510 829,036 43.8 41,761 2.2 22,578 Oil Palm Cultivation Areas for Johore Suitability Areas (Marginal) for Oil Palm Cultivation in Johore Oil Palm Planted on Suitability (Marginal) land in Johor Annual Average Rainfall Annual Average Temperatures Soil Suitability Sub-Classes Classification by Terrain Limits: (Class 3 or less) where; 2000-3000mm 24°C to 28° Suitable : 1n, 2d and 2dt Class 1 Class 2 Class 3 0-2° >2-6° >6-12° Marginal: 2DGn, 2Gn, 2Dt(G), 2Gnt, 2cGnt, 2cd, 2cdGnt, 2dnT, 2dnt, 2nT, 2nT(G), 3D(nt), 3G, 3G(cn), 3G(cnT), 3G(n),3G(nt), 3G(t), 3R(n), 3d, 3d(n), 3d(t), 3dt, 3t(G), 4dt, 4dt(n)

Composites of MJO Phases, Anomalous OLR, Anomalous Geopotential Height at 500hPa & wind at 850hPa during JJA