Climate prediction Ding Yihui, Liu Yanju, Liu Yiming, Shi Xueli National Climate Center, CMA

1. 9-yr seasonal prediction for flooding period NCC-CGCM

1998 summer, heavy floods occurred in whole Yangtze basins, predictions for range and intensity are quite successful Seasonal precipitation prediction (left) and observation (right) for 1998 summer (Anomaly percentage:%)

1999 年夏季，预报为中等旱涝年景，多雨范围比前一年小 ，少 雨范围比前一年大，与实况一致。但预报主要雨带偏北 ，位于 江淮、黄淮、华北中南部到东北东部一带；实况是主要雨带偏南， 位于长江以南地区；出入较大。 1999 年夏季（ 6 ～ 8 月）降水量距平百分率图 1999 年夏季（ 6 ～ 8 月）降水量距平百分率预报图 Seasonal precipitation prediction (left) and observation (right) for 1999 summer (Anomaly percentage:%)

2000 summer, predictions are right for flood over Huanghe and Huaihe valleys and drought over some regions in North of China, The prediction evaluation highly reached 76%, with 11% increase compared to which in “9th 5-yr plan” and being the third since Seasonal precipitation prediction (left) and observation (right) for 2000 summer (Anomaly percentage:%)

2001 summer, the prediction is consistent to observation, there are flood over East of Huanghe and Huaihe valleys, lower of Yangtze basin, most regions in South of China, east of Southwest China, northwest of Sinkiang, with drought over most regions in North China and Yangtze basins. But raininess belts in prediction is weaker than observation in South of China and stronger in north of China. Seasonal precipitation prediction (left) and observation (right) for 2001 summer (Anomaly percentage:%)

2002 年夏季（ 6 ～ 8 月）降水量距平百分率图 2002 年夏季（ 6 ～ 8 月）降水量距平百分率预报图 预报 2002 年夏季，我国多雨的范围比前一年增大，江淮、长江中 下游、江南东部、华南大部、云贵高原南部等地降水偏多，部分地 区洪涝灾害比前一年加重。北方大部地区以少雨为主，华北、西北 东部和东北的部分地区要多年连续干旱。上述预报意见基本正确。 但部分地区预报与实况有出入。 Seasonal precipitation prediction (left) and observation (right) for 2002 summer (Anomaly percentage:%)

预报总体上正确：北方降水比前四年增多，可能出 现南北两支多雨带。江淮地区少雨，有夏旱（高温 少雨）。长江流域不会出现严重洪涝。登陆台风个 数偏少。但淮河流域突发性暴雨未报出。 Seasonal precipitation prediction (left) and observation (right) for 2003 summer (Anomaly percentage:%)

2004 Prediction OBS

2005 Prediction OBS

2006 Prediction OBS

2. Regional climate model to predict flooding seasons

LPM Land-surface 1. BATS 2. LPM Cumulus 1. Kuo － Anthes 3. MFS Convective 2. Grell 4. Betts － Miller Rad. Trans. 1. CCM2 2. CCM3 1. Non-Holtslag 3-6. TKE 2. Holtslag (various formula) Physical Process Parameterization Schemes of RegCM_NCC PBL

Model Domain of operational hindcasts & predictions

Precipitation Anomaly over 160 station (upper) and North China (below) in summer simulation

ACC distribution of summer precipitation Simulation Hindcast

Assessment of RegCM_NCC hindcast (1) yearPcSS1SS2ACCTs ave Ave in NCC

Precipitation Anomaly of summer 2002 (%) Prediction OBS Above normal: the mid-low reach of the Yangtze River valley, most part of the South china; Below normal: most regions to the north of the Yangtze River valley

Precipitation Anomaly of summer 2003 (%) Above normal: regions between the Yellow river and Huaihe river valley; Below normal:Regions to the south of the Yangtze river valley, and Inner-Mongolia Prediction in March Observation Prediction in May

Precipitation Anomaly of summer 2004 (%)

新疆西北部、河套地区、华北大部、东北西部以及华南部分地区降水较常年同期 偏少；西南地区大部、黄淮、江淮、江南部分地区降水较常年同期偏多，其余地 区接近常年同期。 Precipitation Anomaly of summer 2006 (%)

3. Monsoon onset simulation by using high-resolution regional climate model

4. Prediction of South China Sea summer monsoon onset with POAMA

POAMA Newest operational model: 9 months AGCM: BAM, T47,17 layers OGCM: ACOM2 （ Version 2 ）,25 layers, 196*182 grids

U850 OLR 2003 OLR （ ） NCEP Forecast (right) Observation (left) Ensemble forecast 16 members( April15 _30, 2003)

Precipitation Ensemble forecast 16 members( April15 _30, 2003) Observation (left) Forecast (right)

accepted onset index:Wang.et.al(2004) Actual onset date （ 4 th pentad of May ） accepted （ 17/30=57% ） Actual onset date （ 4 th pentad of May ）

(a) (b) 850 hPa Zonal wind hPa Zonal wind March April Taylor diagram Taylor diagram summary of POAMA predictions for Diagrams on up (bottom) are for ensemble members with lead times of (30-1) days. The number on each of the diagram signifies the starting date for the ensemble member and CLM the Climatological prediction Cor=0.625 Rmse=4.6

(c) (d) OLR March April 2003 Taylor diagram Cor=0.51 Rmse=36

(e) (f) precipitation Taylor diagram 2003 March April Cor=0.73 Rmse=7

Case Observation

（a）（a） March 850 hPa Zonal wind （b）（b） April 泰勒图的分析 2004 Taylor diagram Cor=0.47

OLR (a) (b) 泰勒图的分析 2004 March April Taylor diagram Cor=0.35

accepted （ 18/30=60% ） Actual onset date （ 4 th pentad of May ） Actual onset date （ 4 th pentad of May ）

U850 OLR Observation (left) Forecast (right) Ensemble forecast 16 members( April15 _30, 2004)