Fifth Session of the South Asian Climate Outlook Forum (SASCOF-5) JMA Seasonal Prediction of South Asian Climate for Summer 2014 Hitoshi Sato Climate Prediction Division Japan Meteorological Agency

Fifth Session of the South Asian Climate Outlook Forum (SASCOF-5) Contents Outline of JMA Seasonal Ensemble Prediction System Current oceanic condition JMA’s seasonal numerical ensemble prediction Summary

Fifth Session of the South Asian Climate Outlook Forum (SASCOF-5) Contents Outline of JMA Seasonal Ensemble Prediction System Current oceanic condition JMA’s seasonal numerical ensemble prediction Summary

Fifth Session of the South Asian Climate Outlook Forum (SASCOF-5) Specification of Seasonal EPS ModelCGCM (Last upgrade: February 2010) Resolution[Atmosphere] H: TL95 (~180 km), V: L40 (up to 0.4 hPa) [Ocean] H:1.0 º lon.,0.3–1.0 º lat.(75 º S – 75 º N), V: L50 Forecast range7 months Initial conditions[Atmosphere] JCDAS (JMA Climate Data Assimilation System) [Ocean] MOVE/MRI.COM-G (Ocean Data Assimilation) [Land] Climatology Boundary conditionsSST: Predicted, Sea ice: Climatology Ensemble methodCombination of Breeding of Growing Modes (BGM) and Lagged Average Forecast (LAF) Ensemble size51 (9 BGMs & 6 initial days with 5-day LAF) Freq. of model product creation Once a month (around 20th of every month) In this presentation, Initial date: 11 April 2014 Forecast period: JJA (JJAS) 2014

Fifth Session of the South Asian Climate Outlook Forum (SASCOF-5) Prediction Skill of Seasonal EPS 5% significant level SST Precipitation Anomaly Correlation of SST and Precipitation for JJA (Initial month: April) Hindcast experiments for 30 years (1979 – 2008)

Fifth Session of the South Asian Climate Outlook Forum (SASCOF-5) Prediction Skill of Seasonal EPS Area-averaged precipitation for JJA (Initial month: April) South Asia CI2 DL 60E90E115E140E170E170W 5N 5S 10N 20N 30N South Asia CI2DL Precipitation Anomaly Hindcast experiments for 32 years (1979 – 2010) r=0.43 [mm/day] r=0.62r=0.72 South Asia

Fifth Session of the South Asian Climate Outlook Forum (SASCOF-5) Prediction Skill of Seasonal EPS ROC Area of Precipitation for JJA (Initial month : April) Below-normal Near-normal Above-normal Hindcast experiments for 30 years (1979 – 2008)

Fifth Session of the South Asian Climate Outlook Forum (SASCOF-5) Contents Outline of JMA Seasonal Ensemble Prediction System Current oceanic condition JMA’s seasonal numerical ensemble prediction Summary

Fifth Session of the South Asian Climate Outlook Forum (SASCOF-5) Monthly Mean SST Anomalies (March 2014) Pacific –ENSO neutral conditions continued in March –Above normal in the western equatorial Pacific. Indian Ocean –Below normal in the northern part and above normal in the southern part. –Area-averaged SST in the tropical Indian Ocean (IOBW) region was near normal. 60N 30N EQ 30S [℃][℃]

Fifth Session of the South Asian Climate Outlook Forum (SASCOF-5) SST Indices NINO ℃ ℃ SST indices are defined as deviations from the climatological mean based on a sliding 30-year period, removing long-term trend. NINO.3 IOBW 20N 20S 40E100E 130E 15N 5N 5S 150E NINO.WEST EQ March 2014 Neutral EL Niño La Nina IOBW （ Tropical Indian Ocean) ℃ NINO.WEST

Fifth Session of the South Asian Climate Outlook Forum (SASCOF-5) Contents Outline of JMA Seasonal Ensemble Prediction System Current oceanic condition JMA’s seasonal numerical ensemble prediction Summary

Fifth Session of the South Asian Climate Outlook Forum (SASCOF-5) Predicted SST and OHC for JJA 2014 (Initial date: 11 April 201 ４ ) [℃][℃] Indian OceanPacificAtlantic Subsurface warm waters are predicted to migrate eastward in spring. In summer, it is likely that El Niño conditions will develop. In the Indian Ocean, it is likely that SST will be near normal or above normal in summer. Time-longitude cross section along the EQ (April-September) Indian OceanPacificAtlantic [℃][℃] [℃][℃] Ensemble mean SST anomaliesOcean Heat Content anomalies SST for JJA 2014 anomaly

Fifth Session of the South Asian Climate Outlook Forum (SASCOF-5) Predicted Area-averaged SST Anomalies for JJA 2014 (Initial date: 11 April 2014) Above normal Near normalAbove or near normal [℃] [℃] [℃] [℃] [℃] [℃] 51 ensemble members IOBW - SSTNINO.WEST - SSTNINO.3 - SST

Fifth Session of the South Asian Climate Outlook Forum (SASCOF-5) Velocity potential in the upper troposphere is predicted to be positive (convergence) anomaly over the Indian Ocean negative (divergence) anomaly over the central and eastern Pacific. Predicted Atmospheric Fields in the Tropics for JJA 2014 (Initial date: 11 April 2014) [mm/day] [10 6 m 2 /s] CD Precipitation is predicted to be below normal over South Asia and Maritime Continent above normal from tropical northwestern Pacific to the eastern equatorial Pacific. Precipitation Velocity potential at 200 hPa Anomaly (shaded)

Fifth Session of the South Asian Climate Outlook Forum (SASCOF-5) In the lower troposphere, cyclonic circulation anomalies centered to the northeast of the Philippines are predicted, suggesting active western north Pacific monsoon. Anticyclonic circulation anomalies over the northwestern part of south Asia and easterly wind anomalies over the western North Indian Ocean are predicted with moderate prediction skill, indicating the possibility of weaker-than-normal monsoon circulation. Predicted Atmospheric Fields in the Tropics for JJA 2014 (Initial date: 11 April 2014) [10 6 m 2 /s] C A Anomaly (shaded) Stream function at 850 hPa Wind anomaly (vector) and Stream function anomaly (shaded) at 850 hPa

Fifth Session of the South Asian Climate Outlook Forum (SASCOF-5) Predicted Precipitation (Initial date: 11 April 2014) JJA 2014 [mm/day] In general, precipitation over south Asia is predicted to be below normal or near normal. –Below normal over northwestern and southern parts of south Asia. –Near normal over the remaining parts of south Asia. JJAS 2014 Anomaly (shaded)

Fifth Session of the South Asian Climate Outlook Forum (SASCOF-5) Below or near normal (Large ensemble spread) Near or above normalAbove normal Histograms of Area-averaged Precipitation Anomaly for JJA 2014 Initial date: 11 April 2014 Prediction Skill (Anomaly Correlation, hindcast) ACC=0.43ACC=0.62ACC=0.72 Dry WetDryWet DryWet [σ] 51 ensemble members

Fifth Session of the South Asian Climate Outlook Forum (SASCOF-5) Model Output Statistics (MOS) technique based on the 30 years hindcast is used. Masked grids denote insufficient prediction skill (ROC area score < 0.5). Most likely category of precipitation is below normal over northwestern and southern parts of south Asia. Uncertainty should be considered. Probability (most likely category of precipitation for JJA 2014) Initial date: 11 April 2014

Fifth Session of the South Asian Climate Outlook Forum (SASCOF-5) Summary JMA Seasonal Ensemble Prediction System predicts as follows: (Outlook for Oceanic conditions) El Niño conditions will develop in summer. Over the Indian Ocean, SSTs are predicted to be slightly above normal. (Outlook for Summer Monsoon Rainfall over South Asia) Area-averaged precipitation over south Asia is expected to be below normal or near normal. Below normal precipitation is expected over northwestern and southern parts of south Asia.

Fifth Session of the South Asian Climate Outlook Forum (SASCOF-5) References Tokyo Climate Center JMA El Niño outlook Numerical model prediction Ensemble mean forecast maps 3-month prediction Warm/cold season prediction Probabilistic forecast with the numerical guidance 3-month prediction Warm/cold season prediction Climate monitoring

Fifth Session of the South Asian Climate Outlook Forum (SASCOF-5) Backup slides

Fifth Session of the South Asian Climate Outlook Forum (SASCOF-5) Predicted area-averaged SST anomalies NINO.3 NINO.WEST IOBW

Fifth Session of the South Asian Climate Outlook Forum (SASCOF-5) Correlation between Area-averaged Precipitation and NINO.3-SST (Ensemble members for JJA 2014 starting in April 2014) South Asia CI2 DL 60E90E115E140E170E170W 5N 5S 10N 20N 30N Negative correlation between precipitation over the South Asia and NINO.3-SST La Niña El Niño La Niña El Niño La Niña El Niño Ensemble member

Fifth Session of the South Asian Climate Outlook Forum (SASCOF-5) Precipitation anomaly for JJA of drought year (Initial month: March, Hindcast: ) [mm/day] ForecastAnalysis (GPCP v2.2) Forecast Analysis (GPCP v2.2) South Asia: -0.89South Asia: South Asia: -0.61South Asia: South Asia: -0.85South Asia: South Asia: -0.88South Asia: South Asia: +0.01South Asia: -0.61

Fifth Session of the South Asian Climate Outlook Forum (SASCOF-5) Precipitation over South Asia for JJA vs. NINO.3-SST ( , Analysis) Precipitation over South Asia for JJA has –Positive correlation with NINO.3-SST for last DJF –Negative correlation with NINO.3-SST for JJA South Asia NINO.3-SST (JJA) NINO.3-SST (last DJF) CI2 DL

Fifth Session of the South Asian Climate Outlook Forum (SASCOF-5) Composite maps for JJA El Niño years (1982, 1983, 1987, 1991, 1992, 1993, 1997, 2002) SST Precipitation 200 hPa velocity potential 850 hPa stream function

Fifth Session of the South Asian Climate Outlook Forum (SASCOF-5) IOBW / NINO.WEST NINO.3 IOBW / NINO.WEST NINO.3 El Niño El Niño years La Niña years La Niña Composite time series of SST indices

Fifth Session of the South Asian Climate Outlook Forum (SASCOF-5) Plan to upgrade JMA’s Seasonal EPS JMA plans to upgrade its seasonal EPS in 2015 AGCM –Increasing resolution (TL95L40 -> TL159L60) –Improvement model physics –introducing stochastic parameterization OGCM –Expansion of target area –to whole globe –Improvement of model physics –Introduction of sea-ice model Improvement of atmospheric analysis for initial condition and creating perturbation