The Simulation And Scenario Analysis On East Asia Climate Using PRECIS

The climate is changing with the main feature of climate warming. In the background of climate warming, the frequency of the weather and climate extremes has increased. The global precipitation will have a tendency that the dry will become drier and the wet will become wetter. Climate model is the essential tool to simulate and predict climate change. Nowadays, many researchers have simulated and predicted climate mean sate and climate extremes with the global climate model and regional climate model. The climate model has been quite reliable as an effective tool for quantitative estimates of future climate change. Even though, there are many uncertainties using climate model to predict future climate. Predict climate change using global climate model not only with single model but also with the multi-model ensemble. But most regional climate models are downscaled by a single GCM. The simulation results of multi-ensemble RCM downscaling analysis will undoubtedly enrich our scientific understanding of the simulation uncertainty.Using the PRECIS regional climate modeling system driven by five members of QUMP(Quantifying Uncertainties in Model Projections) model ensembles developed by Hadley Center/Met Office, this study simulates the surface air temperature, precipitation and climate extremes over 1961~2050 under the IPCC SRES A1 B emission scenario over China.(1) The result shows reasonable capabilities of PRECIS-downscaled QUMP members in simulating the Baseline(1961~1990) climatology of surface temperature over China, though general overestimations of temperature values compared with observation were found over several regions. The projection shows increases in surface temperature simulated by all of the ensemble members, but differences of the warming tendency were also found among these members. The simulated annual mean daily minimum temperature show the most significant warming compared with the annual mean daily mean temperature and the daily maximum temperature. Besides Q10, the warming simulated by each member is corresponding with the climate sensitivity of the driven GCM. Overall, the most significant projected warming was shown over Northwest China with the range 2.08~2.61 ℃, while the lowest range 1.33~1.84 ℃ was located over the South China. However, differences of projected regional scale warming were also shown among each member.(2) QUMP members show reasonable capabilities in simulating the Baseline climatology of precipitation over china, and the zonal simulation is better than longitudinal simulation. It is not a good simulation of the southeast high value precipitation for lack of simulating East Asian monsoon. QUMP members have capability in simulating monthly trend but there is a certain bias especially in spring. There is a gap of time trends simulation between simulations and observation. The simulation of temperature is better than precipitation. The projection shows increases in precipitation simulated by all of the ensemble members. The change of precipitation and time trends simulated by each member is corresponding with the climate sensitivity of the driven GCM. Overall, the most significant projected wetting was shown over North China with the range 0.2~0.4mm/d, while the lowest range-0.02~0.13 mm/d was located over the Southwest China. However, differences of projected regional scale wetting were also shown among each member.(3) QUMP members show reasonable capabilities in simulating the Baseline climatology of climate extremes over china except ECE, though general bias of temperature values compared with observation were found over several regions. The time series of simulated temperature extremes are similar with the observation while the liner trends are quite different compared with observation. The time series of simulate extreme precipitation index have difference with the observation. In the middle of 21 st century, the extreme warm events including HTD and HTE have an increasing tendency while the extreme cold events including FD and ECE have a decreasing tendency. The extreme precipitation events including FEPE, WD, R5 D and SPI will increase while CDD will decrease. Among the QUMP members, there is significant change of high sensitivity Q13 and middle sensitivity Q0、Q7.