The aim of this initiative is to evaluate the impact of realistic snow initialisation on skill of subseasonal-to-seasonal forecasts by state-of-the-art dynamical forecast systems. The modeling strategy follows the one developed during the GLACE2 initiative, which was aimed at assessing the impact of soil moisture on seasonal forecast (e.g. Koster et al., 2011). These forecast experiments would be relevant for the assessment of forecasting skill, for the attribution of climate pattern variability and extreme weather/climate events to snow forcing, and for subseasonal-to-seasonal predictions during the Year of Polar Prediction (YOPP).

Participating members (so far) : ECMWF (UK), BSC (Spain), NILU (Norway), Chonnam National University - UNIST (South Korea), KOPRI (South Korea), IAP (China), Gøteborg University (Sweden)

Planned experiments : multi-model seasonal (about 3-month) simulations covering at least a decade (2004 à…), with either realistic or else climatological snow conditions, and start dates throughout fall to spring.

  • Completed experiments : ECMWF
  • Analysis : deterministic and probabilistic forecast (skill score, reliability diagrams,…)

Data Center: to be established in Korea (KOPRI), with support of 1 person

Expected outcome:

  • estimate the impact of snow on surface air temperature and circulation at subseasonal time-scale
  • improved and more reliable snow prediction


Koster R.D. et al. (2011), GLACE2: the second phase of the global land atmosphere coupling experiment: soil moisture contributrion to subseasonal forecast skill. J Hydrometeorol 12:805–822.

Orsolini, Y.J., Senan, R., Balsamo, G., Doblas-Reyes, F., Vitart, D., Weisheimer, A., Carrasco, A., Benestad, R. (2013), Impact of snow initialization on sub-seasonal forecasts , Clim. Dyn., DOI: 10.1007/s00382-013-1782-0

Jeong, J.H., H.W. Linderholm, S.-H. Woo, C. Folland, B.-M. Kim, S.-J. Kim and D. Chen (2013), Impact of snow initialization on subseasonal forecasts of surface air temperature for the cold season, J. Clim., 26, 1956-1972, doi:10.1175/JCLI-D-12-001.59.1