Numerical modelling of possible catastrophic climate changes E

Numerical modelling of possible catastrophic climate changes E. V. Volodin, N. A. Diansky, V. Ya. Galin, V. P. Dymnikov, V. N. Lykossov Institute of Numerical Mathematics (INM) Russian Academy of Sciences, Moscow Corresponding e-mail: dinar@inm. ras. ru

Global ocean general circulation model as ocean component of the climate system model: characteristics of global ocean circulation simulated in experiments under IPCC scenarios. COUPLED ATMOSPHERE-OCEAN GSM (INMCM 3. 0) AGCM Finite difference model has spatial resolution of 5° in longitude and 4° in latitude and 21 levels in sigma-coordinates from the surface up to 10 h. Pa. In radiation absorption of water vapour, clouds, CO 2, O 3, CH 4, N 2 O, O 2 and aerosol are taken into account. Solar spectrum is divided by 18 intervals, while infrared spectrum is divided by 10 intervals. Deep convection, orographic and non-orographic gravity wave drag are considered in the model. Soil and vegetation processes are taken into account. Non-flux-adjusted coupling OGCM: Global ocean σ-model with resolution is 2. 5°x 2°x 33 including sea ice thermodynamics. Coupling includes interactive river runoff.

The results of the experiments carried out according to IPCC scenario. (Also presented in the IPCC Fourth Assessment Report) IPCC scenario of time evolution of CO 2, CH 4, N 2 O, SOL, VLC

Model climate in 20 th century. Global temperature anomaly in 1871 -2000, 10 -yr moving average (thick line is observations, thin line is model) Meridional heat transport averaged for 1980 -1999. Mean sea level evolution

Model climate in 20 th century. The first SVD modes of SLP (top) and SST (bottom) in the North Atlantic region in winter for the model (left) and observations (right) for 1950 -1999.

Model climate in 20 th century: El-Nino reproducing. Root mean square (RMS) of SST anomaly for 1950 -1999. INMCM 3. 0. Power spectra of SST anomaly in Nino 3 region (5°N– 5°S, 150°W– 90°W)

Climate changes according IPCC scenario A 1 B: INMCM 3. 0 annual mean surface warming (surface air temperature, in °C) for the A 1 B scenario 2080– 2099. Multi-model mean of annual mean surface warming (surface air temperature, in °C) for the A 1 B scenario 2080– 2099. Stippling denotes where the multi-model ensemble mean exceeds the intermodel standard deviation.

ΔT (2081 -2100)– (1981 -2000) DEC-FEB JUN-AUG

Climate changes according IPCC scenarios: Time series of globally averaged (left) surface warming (surface air temperature, in °C) and (right) precipitation (in %) from the various IPCC models for the scenarios (top) A 2, (middle) A 1 B and (bottom) B 1 scenario. Values are annual means, relative to the 1980– 1999 average from the corresponding 20 th century simulations, with any linear trends in the corresponding control run simulations removed. Shown in black are the multi-model (ensemble) mean series.

Climate changes according IPCC scenarios: Projected global average sea level rise (m) due to thermal expansion during the 21 st century relative to 2000 under SRES scenarios a) A 1 B, b) A 2 and c) B 1.

September arctic sea ice area (106 km 2) in control run (blue), 20 c 3 m(green), B 1 (yellow), A 1 B (orange) and A 2 (red)

ΔT DJF (2101 -2200)(1901 -2000) ALL MONTHS WARM MONTHS COLD MONTHS

ΔT JJA ALL MONTHS WARM MONTHS COLD MONTHS

ΔP/P MAY-SEP ALL MONTHS WET MONTHS DRY MONTHS

Change of vegetation period length (top) and number of frost days (bottom) (2081 -2100) – (1981 -2000) A 1 B

Change of maximum dry period, days (top) and number of days with P>10 mm (2081 -2100) – (1981 -2000) A 1 B.

PERMAFROST 1981 -2000 2081 -2100 B 1 2081 -2100 A 2