Climate Simulations of the 20 th Century by using NCC/IAPT63 Model

1. Climate Simulations of the 20th Century by using NCC/IAPT63 Model Ying XU, Xuejie GAO, Yong LUO , Panmao ZHAI and Yihui DING (National Climate Center, China Meteorological Administration, Beijing)

2. Outline • Model Description • Experiment design • Result analysis • Summary • Future plan

3. Model Description

4. Model Description • The atmospheric component of the model (AGCM) : 16 levels with a horizontal resolution of 1.875 degree of latitude by 1.875 degree of longitude, which produces a global grid of 192×96 grid cells; • The reference pressure is 1013.25hPa, time integration step is 22.5 minutes

5. Model Description • The oceanic component of the model (OGCM) was developed by IAP (Institute of Atmospheric Physics, CAS). It uses a triangular-truncated spectral horizontal grid system, with same horizontal resolution as the AGCM. • Altogether 30 vertical levels, of which 20 levels for the upper ocean 1000m.

6. Model Description • Following parameterization schemes of physicalprocesses are included: • radiation scheme: cloud and radiation processes and the scatter process ofcloud were considered. • The GHG absorbers includeH2O, CO2 and O3 and direct influence of aerosols is prescribed • vertical diffusion:turbulent vertical fluxes were simulated through the process of vertical diffusion

7. Model Description • gravity wave drag • convection: mass flux scheme for deep, shallow and mid-level convection clouds were represented by a bulk model and include updraft and downdraft mass fluxes • land-surface processes • sea-ice: thermodynamic sea-ice

8. Experiments Part I:Two simulations for climate variation from 1900~2000 year using the NCC/IAPT63 coupled model based on two different radiation schemes Part II: Four simulations from 1948~2003 forced by HADISST and Sea Ice data. Two simulations have been completed, and another two are undergoing. Simulations were based on forcing from change in CO2, ozone, but not including that of aerosols, volcano and solar radiation. Reference period: 1971~2000

9. Result Analysis

10. Part I Simulation of climate variation from 1900~2000 year using NCC/IAPT63 coupled model

11. Change of temperature and precipitation over Globe in 20th century (unit:℃) (w.r.t.1961~1990)

12. Change of temperature and precipitation over China in 20th century (unit:℃) (w.r.t.1961~1990)

13. Long-term trend of annual mean T and Pr(%/100a)(1901~2000)

14. Correlation between simulation and observation in last 100 years

15. Part I summary • NCC/IAPT63 model was applied for transient climate change experiments on the 20th century. Experiments include anthropogenic forcing, but do not include natural forcing and troposphere aerosols. • In these preliminary experiments, variation in global annual mean surface temperature seems to be generally agreed with observations. .

16. Part II Experiments forced by HADISST1.1 for the 1948~2003

17. MSLP (Jan)

18. MSLP (Jul)

19. MSLP (annual mean)

20. 1月份30年平均海平面气压场 低压位于高纬的海洋区，沿海岸线等压线密集。在欧亚大陆和北美大陆以及副热带大西洋地区是地面高压带。在数值实验中，只在下边界是加热里作用时，也能模拟出和真实情况相似的场，说明热力在维持高纬海洋区地面地压时很重要。 高 高 低 低 高 高 高 低 7月份30年平均海平面气压场 海平面气压于1月份近于相反，在欧亚大陆上是庞大的热低压，而在两大洋上为强大的副热带高压，这反映了热力强迫的显著差异。地形强迫主要反映在山脉两侧海平面气压梯度的差异上。在高空西风带地区，通过山脉海平面气压从西向东减小。 低

21. Distribution of 850hPa height field (1971~2000 mean) in Jan. Simulation observation

22. Distribution of 850hPa height field (1971~2000 mean) in Jul. Simulation observation

23. Distribution of annual mean heights at 850hPa Simulation observation

24. Distribution of 500hPa height in Jan(1971~2000 ) Simulation observation

25. Distribution of 500hPa heights in Jul(1971~2000) Simulation observation

26. Distribution of annual mean 500hPa heights (1971~2000 ) Simulation observation

27. Mean Jan 850hPa wind fields (1971~2000 ) Simulation observation

28. Mean Jul 850hPa wind fields (1971~2000) Simulation observation

29. Annual mean 850hPa wind field (1971~2000) Simulation observation

30. Mean Jan 200hPa wind field (1971~2000) Simulation observation

31. Mean Jul. 200hPa wind field from (1971~2000) Simulation observation

32. 30 year mean U lat.-P cross section in January Simulation observation

33. 30year mean U lat.-P section plane in July Simulation observation

34. 30year mean Temperature lat.-P cross section for January Simulation observation

35. 30year mean Temperature lat.-P cross section for July Simulation observation

36. Annual mean 30year mean Temperature Lat.-P cross section Simulation observation

37. Surface air temperature in January Simulation observation

38. Surface air temperature in July Simulation observation

39. Annual mean surface air temperature(1971~2000) Simulation observation

40. Mean State of January Precipitation

41. Mean State of July Precipitation

42. Mean State of Annual Precipitation

43. Month mean time-series of global surface temperature from 1948~2003

44. Annual mean global surface temperature during 1948~2003

46. Part II summary • HADISST1.1 dataset is being used in some simulations of climate change of 20th Century • Results of simulation for mean state seems to be encouraging • Simulations for climate variations need to be greatly improved

47. Future plan • Further simulations • To improve the simulation results • More thorough and robust analysis